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Complete Shoulder and Hip Blueprint Review

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Juicing for Your Manhood: Increase Testosterone Review

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Smoke Free In One Hour Review

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Low Carb Weekly Meal Plans Review

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Face Engineering Exercises Review

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Big Natural Testicles Program Review

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The Parkinson's-Reversing Breakthrough Review

Articles

Slow and Fast Twitch Fibers

Skeletal muscle fibers can be divided on the basis of their contraction speed time required to reach maximum tension into slow-twitch, or type I, fibers, and fast-twitch, or type II, fibers. These differences are associated with different myosin ATPase isoenzymes, which can also be designated as slow and fast. The two fiber types can be distinguished by their ATPase isoenzyme when they are appropriately stained fig. 12.23 . The extraocular muscles that position the eyes, for example, have a...

Twitch Summation and Tetanus

When the muscle is stimulated with a single electric shock of sufficient voltage, it quickly contracts and relaxes. This response is called a twitch. Increasing the stimulus voltage increases the strength of the twitch, up to a maximum. The strength of a muscle contraction can thus be graded, or varied an obvious requirement for the proper control of skeletal movements. If a second electric shock is delivered immediately after the first, it will produce a second twitch that may partially ride...

The Internal Environment and Homeostasis

An amoeba and a human liver cell both obtain their energy by breaking down certain organic nutrients. The chemical reactions involved in this intracellular process are remarkably similar in the two types of cells and involve the utilization of oxygen and the production of carbon dioxide. The amoeba picks up oxygen directly from the fluid surrounding it its external environment and eliminates carbon dioxide into the same fluid. But how can the liver cell and all other internal parts of the body...

Refractory Period of the Heart

Ventricular muscle, unlike skeletal muscle, is incapable of any significant degree of summation of contractions, and this is a very good thing. Imagine that cardiac muscle were able to undergo a prolonged tetanic contraction. During this period, no ventricular filling could occur since filling can occur only when the ventricular muscle is relaxed, and the heart would therefore cease to function as a pump. The inability of the heart to generate tetanic contractions is the result of the long...

Effects of Blood PO2 on Ventilation

Under normal conditions, blood Po2 affects breathing only indirectly, by influencing the chemoreceptor sensitivity to changes in PcO2- Chemoreceptor sensitivity to PCO gt 2 is augmented by a low PO2 so ventilation is increased at a high altitude, for example and is decreased by a high PO2. If the blood PO2 is raised by breathing 100 oxygen, therefore, the breath can be held longer because the response to increased PCO2 is blunted. When the blood PCO2 is held constant by experimental techniques,...

Lung Volumes and Capacities

An example of a spirogram is shown in figure 16.16, and the various lung volumes and capacities are defined in table 16.3. A lung capacity is equal to the sum of two or more lung volumes. During quiet breathing, for example, the amount of air expired in each breath is the tidal volume. The maximum amount of air that can be forcefully exhaled after a maximum inhalation is called the vital capacity, which is equal to the sum of the inspiratory reserve volume, tidal volume, and expiratory reserve...

Inspection And Palpation Of The Precordium

Inspection and palpation of the cardiac pulsations of the anterior chest have been practiced by physicians since ancient times and have a solid scientific basis. The results of precordial inspection and palpation have been correlated with noninvasive studies, hemodynamic data, and surgical and autopsy studies202,203 and remain an important part of the cardiovascular examination. Their usefulness depends on an understanding of cardiovascular physiology, the proficiency of the examiner, and his...

Digestion and Absorption in the Stomach

Proteins are only partially digested in the stomach by the action of pepsin, while carbohydrates and fats are not digested at all by pepsin. Digestion of starch begins in the mouth with the action of salivary amylase and continues for a time when the food enters the stomach, but amylase soon becomes inactivated by the strong acidity of gastric juice. The complete digestion of food molecules occurs later, when chyme enters the small intestine. Therefore, people who have had partial gastric...

Ankle Jerk Reflex

A neurological reflex depends on an arc which consists of an afferent pathway, which is activated by a specific receptor, an efferent system, which activates a stereotyped response, and a simple or complex pathway that interconnects the afferent and efferent systems. Since the reflex response to an appropriate stimulus is involuntary, disturbances of reflexes afford objective signs of neural dysfunction. The deep tendon reflexes of the limbs provide essential information about Lhe status of the...

Regulation of Blood Volume by the Kidneys

The formation of urine begins in the same manner as the formation of tissue fluid by filtration of plasma through capillary pores. These capillaries are known as glomeruli, and the filtrate they produce enters a system of tubules that transports and modifies the filtrate by mechanisms discussed in chapter 17 . The kidneys produce about 180 L per day of blood filtrate, but since there is only 5.5 L of blood in the body, it is clear that most of this filtrate must be returned to the vascular...

Tonic and Phasic Receptors Sensory Adaptation

Some receptors respond with a burst of activity when a stimulus is first applied, but then quickly decrease their firing rate adapt to the stimulus if the stimulus is maintained. Receptors with this response pattern are called phasic receptors. Receptors that produce a relatively constant rate of firing as long as the stimulus is maintained are known as tonic receptors fig. 10.1 . Phasic receptors alert us to changes in sensory stimuli and are in part responsible for the fact that we can cease...

Female Reproductive System

1. any disease that affects women 7. gynecologist gi-ne-KOL-o-jist 8. anovulatory an-OV-u-1a-1o-re 11. dysmenorrhea DIS-men-o-re-a 12. oligomenorrhea ol-i-go-men-o-RE-a 14. ovariopexy o-var-e-o-PEK-se also oophoropexy o-of-o-ro-PEK-s e 15. ovariocentesis o-var-e-o-sen-TE-sis 16. oophorectomy o-of-o-REK-to-me 1. plastic repair of an oviduct 2. surgical removal of the uterus 4. pertaining to the uterus and bladder 5. instrument for measuring the vagina 7. salpingopexy sal-PING-go-pek-se 8....

Effects of Blood PCO2 and pH on Ventilation

Chemoreceptor input to the brain stem modifies the rate and depth of breathing so that, under normal conditions, arterial PCo2, pH, and Po2 remain relatively constant. If hypoventilation inadequate ventilation occurs, PCO2 quickly rises and pH falls. The fall in pH is due to the fact that carbon dioxide can combine Sensory nerve fibers in vagus nerve Sensory nerve fibers in vagus nerve Figure 16.26 Sensory input from the aortic and carotid bodies. The peripheral chemoreceptors aortic and...

Extracellular Osmolarity and Cell Volume

We can now apply the principles learned about osmosis to cells, which meet all the criteria necessary to produce an osmotic flow of water across a membrane. Both the intracellular and extracellular fluids contain water, and cells are surrounded by a membrane that is very permeable to water but impermeable to many substances nonpenetrating solutes . About 85 percent of the extracellular solute particles are sodium and chloride ions, which can diffuse into the cell through protein channels in the...

Circulatory Changes During Exercise

While the vascular resistance in skeletal muscles decreases during exercise, the resistance to flow through the visceral organs and skin increases. This increased resistance occurs because of vasoconstriction stimulated by adrenergic sympathetic fibers, and it results in decreased rates of blood flow through these organs. During exercise, therefore, the blood flow to skeletal muscles increases because of three simultaneous changes 1 increased total blood flow cardiac output 2 metabolic...

Treatment For Intasubstance Tear Of The Extensor Carpi Ulnaris Tendon

Scapholunate instability is the most common carpal instability. It may occur after a traumatic extension injury to the wrist or result from repetitive stress, as in chronic crutch walking 65 . Weakness and pain about the dorsal radial aspect of the wrist are frequent complaints. On clinical examination, a positive scaphoid shift test may be found 66 . This result consists of a click elicited when bringing the wrist from ulnar to radial deviation while the scaphoid tuberosity is stabilized by...

Transport of Oxygen in Blood

Table 15-7 summarizes the oxygen content of systemic arterial blood we shall henceforth refer to systemic arterial blood simply as arterial blood . Each liter normally contains the number of oxygen molecules equivalent to 200 ml of pure gaseous oxygen at atmospheric pressure. The oxygen is present in two forms 1 dissolved in the plasma and erythrocyte water and 2 re-versibly combined with hemoglobin molecules in the erythrocytes. As predicted by Henry's law, the amount of oxygen dissolved in...

The Primary Neurotransmitters of the ANS Are Acetylcholine and Norepinephrine

In the somatic nervous system, neurotransmitter is released from specialized nerve endings that make intimate contact with the target structure. The mammalian motor endplate, with one nerve terminal to one skeletal muscle fiber, illustrates this principle. This arrangement contrasts with the ANS, where postganglionic axons terminate in varicosities, swellings enriched in synaptic vesicles, which release the transmitter into the extracellular space surrounding the effector cells see Fig. 6.1 ....

Organization of the Respiratory System

There are two lungs, the right and left, each divided into several lobes. Pulmonary is the adjective referring to lungs. The lungs consist mainly of tiny air-containing sacs called alveoli singular, alveolus , which number approximately 300 million in the adult. The alveoli are the sites of gas exchange with the blood. The airways are all the tubes through which air flows between the external environment and the alveoli. Inspiration inhalation is the movement of air from the external...

The Formed Elements of Blood

The formed elements of blood include two types of blood cells erythrocytes, or red blood cells, and leukocytes, or white blood cells. Erythrocytes are by far the more numerous of the two. A cubic millimeter of blood contains 5.1 million to 5.8 million erythrocytes in males and 4.3 million to 5.2 million erythrocytes in females. The same volume of blood, by contrast, contains only 5,000 to 9,000 leukocytes. Erythrocytes are flattened, biconcave discs, about 7 im in diameter and 2.2 im thick....

Pepsin and Hydrochloric Acid Secretion

The parietal cells secrete H , at a pH as low as 0.8, into the gastric lumen by primary active transport involving carriers that function as an ATPase . These carriers, known as H K ATPase pumps, transport H uphill against a million-to-one concentration gradient into the lumen of the stomach while they transport K in the opposite direction fig. 18.8 . At the same time, the parietal cell's basolateral membrane facing the blood in capillaries of the lamina propria take in Cl-against its...

Bone Deposition and Resorption

The skeleton, in addition to providing support for the body, serves as a large store of calcium and phosphate in the form of crystals called hydroxyapatite, which has the formula Cajo PO4 6 OH 2. The calcium phosphate in these hydroxyap-atite crystals is derived from the blood by the action of bone-forming cells, or osteoblasts. The osteoblasts secrete an organic matrix composed largely of collagen protein, which becomes hardened by deposits of hydroxyapatite. This process is called bone...

Explain How Valves In Veins Breathing And Skeletal Muscle Contractions Help Venous Blood Return To The Heart

Most of the total blood volume is contained in the venous system. Unlike arteries, which provide resistance to the flow of blood from the heart, veins are able to expand as they accumulate additional amounts of blood. The average pressure in the veins is only 2 mmHg, compared to a much higher average arterial pressure of about 100 mmHg. These values, expressed in millimeters of mercury, represent the hydrostatic pressure that the blood exerts on the walls of the vessels. The low venous pressure...

Indications for a vaginal examination

Surveillance for cervical carcinoma Symptoms of uterine prolapse Unexplained urinary tract obstruction P Ask the patient to empty Ihe bladder. Position the patient comfortably either on her back or in the left lateral position with her head on a pillow, hips and knees flexed and thighs abducted. P Use a lamp to illuminate the vulva adequately. P Use suitable gloves and lubricate the examining fingers. P Separate the labia minora with the forefinger and thumb of the left hand, bringing into...

Inspiration and Expiration

Between the bony portions of the rib cage are two layers of intercostal muscles the external intercostal muscles and the internal intercostal muscles fig. 16.14 . Between the costal cartilages, however, there is only one muscle layer, and its fibers are oriented in a manner similar to those of the internal inter-costals. These muscles are therefore called the interchondral part of the internal intercostals. Another name for them is the parasternal intercostals. An unforced, or quiet,...

Length Tension Relationship

The strength of a muscle's contraction is influenced by a variety of factors. These include the number of fibers within the muscle that are stimulated to contract, the frequency of stimulation, the thickness of each muscle fiber thicker fibers have more myofibrils and thus can exert more power , and the initial length of the muscle fibers when they are at rest. There is an ideal resting length for striated muscle fibers. This is the length at which they can generate maximum force. When the...

Body Temperatures And Heat Transfer In The Body

The body is divided into a warm internal core and a cooler outer shell Fig. 29.2 . Because the temperature of the shell is strongly influenced by the environment, its temperature is not regulated within narrow limits as the internal body temperature is, even though thermoregulatory responses strongly affect the temperature of the shell, especially its outermost layer, the skin. The thickness of the shell depends on the environment and the body's need to conserve heat. In a warm environment, the...

Visual Acuity and Sensitivity

While reading or similarly viewing objects in daylight, each eye is oriented so that the image falls within a tiny area of the retina called the fovea centralis. The fovea is a pinhead-sized pit fovea pit within a yellow area of the retina called the macula lutea. The pit is formed as a result of the displacement of neural layers around the periphery therefore, light falls directly on photoreceptors in the center fig. 10.41 . Light falling on other areas, by contrast, must pass through several...

Pulse Pressure and Mean Arterial Pressure

When someone takes a pulse, he or she palpates an artery for example, the radial artery and feels the expansion of the artery occur in response to the beating of the heart the pulse rate is thus a measure of the cardiac rate. The expansion of the artery with each pulse occurs as a result of the rise in blood pressure within the artery as the artery receives the volume of blood ejected by a stroke of the left ventricle. Since the pulse is produced by the rise in pressure from dia-stolic to...

Ventilation and Acid Base Balance

The basic concepts and terminology relating to the acid-base balance of the blood were introduced in chapter 13. In brief review, acidosis refers to an arterial pH below 7.35, and alkalosis refers to an arterial pH above 7.45. There are two components of each respiratory and metabolic. The respiratory component refers to the carbon dioxide concentration of the blood, as measured by the PCO2. As implied by its name, the respiratory component is regulated by the respiratory system. The metabolic...

Carrier Mediated Transport

Molecules such as glucose are transported across plasma membranes by special protein carriers. Carrier-mediated transport in which the net movement is down a concentration gradient, and which is therefore passive, is called facilitated diffusion. Carrier-mediated transport that occurs against a concentration gradient, and which therefore requires metabolic energy, is called active transport. In order to sustain metabolism, cells must take up glucose, amino acids, and other organic molecules...

Spiral Organ Organ of Corti

The sensory hair cells are located on the basilar membrane, with their hairs actually stereocilia projecting into the endolymph of the cochlear duct. These hair cells are arranged to form one row of inner cells, which extends the length of the basilar membrane, and multiple rows of outer hair cells three rows in the basal turn, four in the middle turn, and five in the apical turn of the cochlea fig. 10.21 . The stereocilia of the outer hair cells are embedded in a gelatinous tectorial membrane...

Pressure Changes During the Cardiac Cycle

When the heart is in diastole, pressure in the systemic arteries averages about 80 mmHg millimeters of mercury . These events in the cardiac cycle then occur 1. As the ventricles begin their contraction, the intraventricular pressure rises, causing the AV valves to snap shut. At this time, the ventricles are neither being filled with blood because the AV valves are closed nor ejecting blood because the intraventricular pressure has not risen sufficiently to open the semilunar valves . This is...

Fruit And Seed Dispersal

Why are so many species of orchids rare, while dandelions, shepherd's purse, and other weeds occur all over the world Why are some plants confined to single continents, mountain ranges, or small niches occupying less than a hectare 2.47 acres of land The answers to these questions involve many different factors, including climate, soil, the adaptability of the plant, and its means of seed dispersal. How fruits and seeds are transported from one place to another is the subject of the following...

Stress Reaction Femur

Stress fractures of the femur in runners may occur in the femoral neck, trochan-teric and subtrochanteric region, and femoral shaft. These injuries are often not considered in the initial presentation, and a high index of suspicion must be maintained. Patients commonly present with hip, groin, gluteal, thigh, or knee pain, depending on the location of the injury 18,72,73 . In a study by Clement and colleagues 72 , 71 patients who had 74 stress fractures of the femur were studied. Nearly 95 were...

The Ultimate Keto Diet Questions and Answers

Common questions about the Keto Diet, by Sherene Kershner, owner of Evolve 180 Weight Loss Diets seem to go through a lot of fads. Why is the Keto diet better than others I hesitate to use the term &lsquo The Keto Diet&rsquo since there isn&rsquo t really any such thing. That&rsquo s shorthand for a diet that relies on the biological state of ketosis to induce the body to burn fat. With that said, I think diets that focus on ketosis keep coming around because of the many proven health benefits...

The Victim S Injured Extremities Were Immobilized Before Transport. Immobilized Means

During a triathlon, paramedics responded to a scene with multiple patients involved in a serious bicycle accident. B.R., a 20-year-old woman, lost control of her bike while descending a hill at approximately 40 mph. As she fell, two other cyclists collided with her, sending all three crashing to the ground. At the scene, B.R. complained of pain in her head, back, chest, and leg. She also had numbness and tingling in her legs and feet. Other injuries included a cut on her face and on her right...

External Form Of A Woody Twig

A woody twig consists of an axis with attached leaves Fig. 6.1 . If the leaves are attached to the twig alternately or in a spiral around the stem, they are said to be alternate, or alternately arranged. If the leaves are attached in pairs, they are said to be opposite, or oppositely arranged, or if they are in whorls groups of three or more , their arrangement is whorled. The area, or region not structure , of a stem where a leaf or leaves are attached is called a node, and a stem region...

Bowel Obstruction In The Elderly

Causes of bowel obstruction usually specific to the elderly include sigmoid volvulus, Ogilvie's Syndrome, colon carcinoma, and gallstone ileus. These conditions in the elderly patient can lead to gangrene with resulting perforation. Sigmoid volvulus is 20 times more likely in the patient age 60 yr and greater 19 . This age association may be due to acquired redundancy of the sigmoid colon. High-residue diets are believed to be the causative factor in developing a redundant sigmoid 20 . Other...

Methods of Evaluation

Given the poor correlation between symptoms and anatomic failure, a careful and thorough evaluation is warranted. A complete history and physical should be performed with particular attention to the patient's current symptoms. Are the symptoms similar to those experienced before the original surgery Do symptoms of reflux or dysphagia predominate Was there a precipitating event Do antacid medications ameliorate the symptoms The patient's original operative report should be obtained to clarify...

Clinical Features of Infections

Infections in the elderly often present in an atypical, nonclassical fashion. Furthermore, the differential diagnosis of infectious diseases in the elderly differs from the young because it is dependent on both the clinical setting and the patient's underlying functional status. For example, free living, independent, healthy elderly are prone to respiratory infections, such as bacterial pneumonia, genitourinary infections and intraabdominal infections including cholecystitis, diverticulitis,...

Rupture Of The Patellar Tendon

Rupture of the patellar tendon after total knee replacement is a rare and typically devastating problem Fig. 13.1 . Unfortunately, the results of several methods of acute repair are almost uniformly Numerous theories have been postulated to explain the etiology of late rupture of the patellar tendon following TKA. As mentioned previously, improper surgical technique that malaligns the knee or the position of any single component can play a contributory role. Some authors have found its...

Considerations for Esophageal Lengthening Procedures

It is essential that the gastroesophageal junction lie tension free in the abdomen before creating a fundic wrap. The length of tension-free intraabdominal esophagus should be measured after closing the crural defect. When the crura are closed from the caudal condensation of the crural fibers toward the anterior margin of the hiatus, the hiatal orifice is effectively displaced cephalad. This transposition of the hiatal orifice lengthens the intraabdominal segment of esophagus because the...

Hormone Metabolism and Excretion

A hormone's concentration in the plasma depends not only upon its rate of secretion by the endocrine gland but also upon its rate of removal from the blood, either by excretion or by metabolic transformation. The liver and the kidneys are the major organs that excrete or metabolize hormones. The liver and kidneys, however, are not the only routes for eliminating hormones. Sometimes the hormone is metabolized by the cells upon which it acts. Very importantly, in the case of peptide hormones,...

Organs with Dual Innervation

Most visceral organs receive dual innervation they are innervated by both sympathetic and parasympathetic fibers. In this condition, the effects of the two divisions of the autonomic system may be antagonistic, complementary, or cooperative table 9.7 . The effects of sympathetic and parasympathetic innervation of the pacemaker region of the heart is the best example of the antagonism of these two systems. In this case, sympathetic and parasympathetic fibers innervate the same cells. Adrenergic...

Synergistic and Permissive Effects

When two or more hormones work together to produce a particular result, their effects are said to be synergistic. These effects may be additive or complementary. The action of epinephrine and norepinephrine on the heart is a good example of an additive effect. Each of these hormones separately produces an increase in cardiac rate acting together in the same concentrations, they stimulate an even greater increase in car- diac rate. The synergistic action of FSH and testosterone is an example of...

Endocrine Functions of the Placenta

The placenta secretes both steroid hormones and protein hormones. The protein hormones include chorionic gonadotropin hCG and chorionic somatomammotropin hCS , both of which have actions similar to those of some anterior pituitary hormones table 20.7 . Chorionic gonadotropin has LH-like effects, as previously described it also has thyroid-stimulating ability, like pituitary TSH. Chorionic somatomammotropin likewise has actions that are similar to two pituitary hormones growth hormone and...

The Complement System Clears Immune Complexes from Circulation

The importance of the complement system in clearing immune complexes is seen in patients with the autoimmune disease systemic lupus erythematosus SLE . These individuals produce large quantities of immune complexes and suffer tissue damage as a result of complement-mediated lysis and the induction of type II or type III hypersensitivity see Chapter 16 . Although complement plays a significant role in the development of tissue damage in SLE, the paradoxical finding is that deficiencies in C1,...

Chemical Classification of Hormones

Hormones secreted by different endocrine glands vary widely in chemical structure. All hormones, however, can be divided into a few chemical classes. 1. Amines. These are hormones derived from the amino acids tyrosine and tryptophan. They include the hormones secreted by the adrenal medulla, thyroid, and pineal glands. 2. Polypeptides and proteins. Polypeptide hormones generally contain less than 100 amino acids an example is antidiuretic hormone table 11.2 . Protein hormones are polypeptides...

Hormones That Use Second Messengers

Hormones that are catecholamines epinephrine and norepineph-rine , polypeptides, and glycoproteins cannot pass through the lipid barrier of the target cell's plasma membrane. Although some of these hormones may enter the cell by pinocytosis, most of their effects result from their binding to receptor proteins on the outer surface of the target cell membrane. Since they exert their effects without entering the target cells, the actions of these hormones must be mediated by other molecules within...

Chemoreceptors in the Medulla

The chemoreceptors most sensitive to changes in the arterial PCO2 are located in the ventral area of the medulla oblongata, near the exit of the ninth and tenth cranial nerves. These chemoreceptor neurons are anatomically separate from, but synaptically communicate with, the neurons of the respiratory control center in the medulla. An increase in arterial PCO2 causes a rise in the H concentration of the blood as a result of increased carbonic acid concentrations. The H in the blood, however,...

Hormone Transport in the Blood

Peptide and catecholamine hormones are water-soluble. Therefore, with the exception of a few peptides, these hormones are transported simply dissolved in plasma Table 10-2 . In contrast, the steroid hormones and the thyroid hormones circulate in the blood largely bound to plasma proteins. Even though the steroid and thyroid hormones exist in plasma mainly bound to large proteins, small concentrations of these hormones do exist dissolved in the plasma. The dissolved, or free, hormone is in...

Transition Point Between Distended And Collapsed Veins

There are no valves between the right atrium and the internal jugular vein. It follows that the degree of distension in the vein equates to the pressure in the right atrium and the venous waveform provides information about cardiac function. The internal jugular vein enters the neck behind the mastoid process. Il runs deep to the sternomastoid muscle before entering the thorax between its sternal and clavicular heads. Because of its deep position the internal jugular vein can only be examined...

How To Prepare A Wet Mount

Using a pipette bulb, aspirate a small amount of the Proteus culture with a capillary pipette and place a small drop on a clean microscope slide fig. 3.2, step 1 . 2. Carefully place a clean cover glass see Experiment 3.1, procedure 1 over the drop, trying to avoid bubble formation fig. 3.2, step 2 . The fluid should not leak out from under the edges of the cover glass. If it does, wait until it dries before sealing. 3. If you examine the slide immediately, you need not seal the coverslip....

Red Blood Cell Antigens and Blood Typing

There are certain molecules on the surfaces of all cells in the body that can be recognized as foreign by the immune system of another individual. These molecules are known as antigens. As part of the immune response, particular lymphocytes secrete a class of proteins called antibodies that bond in a specific fashion with antigens. The specificity of antibodies for antigens is analogous to the specificity of enzymes for their substrates, and of receptor proteins for neurotransmitters and...

Cubital Tunnel Syndrome

Physiologic and compressive cubital tunnel syndromes have been described. Compressive cubital syndrome may have acute, subacute, or chronic presentation. Normal loss in volume and increased pressure within the tunnel during elbow flexion result in physiologic cubital tunnel syndrome. This can be seen in ''sleep palsy,'' as the arm is held in flexion for prolonged periods of time. Blunt trauma to the cubital tunnel is a typical cause of acute external compression syndrome of the ulnar nerve....

Exchange of Fluid Between Capillaries and Tissues

The distribution of extracellular fluid between the plasma and interstitial compartments is in a state of dynamic equilibrium. Tissue fluid is not normally a stagnant pond rather, it is a continuously circulating medium, formed from and returning to the vascular system. In this way, the tissue cells receive a continuously fresh supply of glucose and other plasma solutes that are filtered through tiny endothelial channels in the capillary walls. Filtration results from blood pressure within the...

Effects of Temperature and pH

An increase in temperature will increase the rate of non-enzyme-catalyzed reactions. A similar relationship between temperature and reaction rate occurs in enzyme-catalyzed reactions. At a temperature of 0 C the reaction rate is immeasurably slow. As the temperature is raised above 0 C the reaction rate increases, but only up to a point. At a few degrees above body temperature which is 37 C the reaction rate reaches a plateau further increases in temperature actually decrease the rate of the...

Reciprocal Innervation and the Crossed Extensor Reflex

In the knee-jerk and other stretch reflexes, the sensory neuron that stimulates the motor neuron of a muscle also stimulates interneu-rons within the spinal cord via collateral branches. These interneu-rons inhibit the motor neurons of antagonist muscles via inhibitory postsynaptic potentials IPSPs . This dual stimulatory and inhibitory activity is called reciprocal innervation fig. 12.29 . When a limb is flexed, for example, the antagonistic extensor muscles are passively stretched. Extension...

Dissociative Identity Disorder

The treatment of dissociative identity disorder is the subject of a voluminous literature, most of which addresses the role of hypnosis to some extent. Numerous articles by the author, summarized in Kluft 1992a,b , and a more recent text by Phillips and Frederick 1995 focus on hypnotic approaches. Dissociative identity disorder involves lesions of identity, consciousness, and memory. Ideally, treatment should help the patient achieve a subjective sense of a unified identity by integrating the...

Transport of Lipids in the Blood

Once the chylomicrons are in the blood, their triglyceride content is removed by the enzyme lipoprotein lipase, which is attached to the endothelium of blood vessels. This enzyme hydrolyzes triglycerides and thus provides free fatty acids and Step 1 Emulsification of fat droplets by bile salts Step 2 Hydrolysis of triglycerides in emulsified fat droplets into fatty acid and monoglycerides Step 3 Dissolving of fatty acids and monoglycerides into micelles to produce mixed micelles Figure 18.35...

Female sex organs produce eggs receive sperm and nurture the embryo

When a mammalian egg matures, it is released from the ovary directly into the body cavity. But the egg does not go far. Each ovary is enveloped by the undulating, fringed opening of an oviduct also known as a Fallopian tube , which sweeps the egg into that tube Figure 43.11 . Fertilization takes place in the oviduct. Whether or not the egg is fertilized, cilia lining the oviduct propel it slowly toward the uterus, a muscular, thick-walled cavity shaped in humans like an upside-down pear. The...

Intrapulmonary and Intrapleural Pressures

The visceral and parietal pleurae are normally flush against each other, so that the lungs are stuck to the chest wall in the same manner as two wet pieces of glass sticking to each other. The intrapleural space contains only a film of fluid secreted by the two membranes. The pleural cavity in a healthy person is thus potential rather than real it can become real only in abnormal situations when air enters the intrapleural space. Since the lungs normally remain in contact with the chest wall,...

Diseases Of Hoffas Fat

A variety of disease entities can affect this structure and cause AKP, including impingement syndromes, postarthroscopy changes, plica syndromes, and mass lesions 27-30 . Acute or repetitive trauma to Hoffa's fat pad can result in edema and hemorrhage. The resultant changes of enlargement put the fat pad at risk for impingement between the femur and tibia. Fibrosis and anterior knee pain can result 27 . This is called Hoffa's disease or syndrome. Acutely, there is high T2 signal and mass effect...

Tissue Patterns In Stems

Primary xylem, primary phloem, and the pith, if present, make up a central cylinder called the stele in most younger and a few older stems and roots. The simplest form of stele, called a protostele, consists of a solid core of conducting tissues in which the phloem usually surrounds the xylem. Protosteles were common in primitive seed plants that are now extinct and are also found in whisk ferns, club mosses see Chapter 21 , and other relatives of ferns. Siphonosteles, which are tubular with...

Anterior Tibial Artery Palpation

The anatomy of he radial, brachial and carotid pulses have been described I p. 83 . Femoral artery. The I'emoral artery is situated just below the inguinal ligament, midway between the anterior superior iliac spine and the pubic symphysis mid-inguinal point . It is immediately lateral to the femoral vein and medial to the femoral nerve. In the obese it can be difficult to feel. Popliteal artery. At the level of the knee crease, the artery lies deep in the popliteal fossa and the pulse is...

Generator Receptor Potential

The electrical behavior of sensory nerve endings is similar to that of the dendrites of other neurons. In response to an environmental stimulus, the sensory endings produce local graded changes in the membrane potential. In most cases, these potential changes are depolarizations that are analogous to the excitatory postsynaptic potentials EPSPs described in chapter 7. In the sensory endings, however, these potential changes in response to environmental stimulation are called receptor, or...

Memory and Learning Require the Cerebral Cortex and Limbic System

Memory and learning are inextricably linked because part of the learning process involves the assimilation of new information and its commitment to memory. The most likely sites of learning in the human brain are the large association areas of the cerebral cortex, in coordination with subcortical structures deep in the temporal lobe, including the hippocampus and amygdala. The association areas draw on sensory information received from the primary visual, auditory, somatic sensory, and...

Significance of Blood PO and PCO2 Measurements

Since blood PO2 measurements are not directly affected by the oxygen in red blood cells, the PO2 does not provide a measurement of the total oxygen content of whole blood. It does, however, provide a good index of lung function. If the inspired air had a normal PO2 but the arterial PO2 was below normal, for example, you could conclude that gas exchange in the lungs was impaired. Measurements of arterial PO2 thus provide valuable information in treating people with pulmonary diseases, in...

Ear Medical Terminology

The ear has the receptors for both hearing and equilibrium. For study purposes, it may be divided into three parts the outer, middle, and inner ear Fig. 18-1 . The outer ear consists of the projecting pinna auricle and the external auditory canal meatus . This canal ends at the tympanic membrane or eardrum, which transmits sound waves to the middle ear. Glands in the external canal produce a waxy material, cerumen, which protects the ear and helps to prevent infection. Spanning the middle ear...

Nitric Oxide and Carbon Monoxide as Neurotransmitters

Nitric oxide NO was the first gas to be identified as a neuro-transmitter. Produced by nitric oxide synthetase in the cells of many organs from the amino acid L-arginine, nitric oxide's actions are very different from those of the more familiar nitrous oxide N2O , or laughing gas, sometimes used as a mild anesthetic in dentistry. Nitric oxide has a number of different roles in the body. Within blood vessels, it acts as a local tissue regulator that causes the smooth muscles of those vessels to...

Control of the Autonomic Nervous System by Higher Brain Centers

Visceral functions are largely regulated by autonomic reflexes. In most autonomic reflexes, sensory input is transmitted to brain centers that integrate this information and respond by modifying the activity of preganglionic autonomic neurons. The neural centers that directly control the activity of autonomic nerves are influenced by higher brain areas, as well as by sensory input. The medulla oblongata of the brain stem is the area that most directly controls the activity of the autonomic...

Skeletal Muscle Action Potential

Brane potential to change after a stimulus is applied is called the time constant or t, and its relationship to capacitance C and resistance R is defined by the following equation In the absence of an action potential, a stimulus applied to the neuronal membrane results in a local potential change that decreases with distance away from the point of stimulation. The voltage change at any point is a function of current and resistance as defined by Ohm's law. If a lig-and-gated channel opens...

Negative Feedback Control of Calcium and Phosphate Balance

The secretion of parathyroid hormone is controlled by the plasma calcium concentrations. Its secretion is stimulated by low calcium concentrations and inhibited by high calcium concentrations. Since parathyroid hormone stimulates the final hy-droxylation step in the formation of 1,25-dihydroxyvitamin D3, a rise in parathyroid hormone results in an increase in production of 1,25-dihydroxyvitamin D3. Low blood calcium can thus be corrected by the effects of increased parathyroid hormone and...

Late Phase Reactions Induce Localized Inflammatory Reactions

As a type I hypersensitive reaction begins to subside, mediators released during the course of the reaction often induce localized inflammation called the late-phase reaction. Distinct from the late response seen in asthma, the late-phase reaction begins to develop 4-6 h after the initial type I reaction and persists for 1-2 days. The reaction is characterized by infiltration of neutrophils, eosinophils, macrophages, lymphocytes, and basophils. The localized late-phase response also may be...

Single Unit and Multiunit Smooth Muscles

Smooth muscles are often grouped into two functional categories single-unit and multiunit fig. 12.35 . Single-unit smooth muscles have numerous gap junctions electrical synapses between adjacent cells that weld them together electrically they thus behave as a single unit, much like cardiac muscle. Most smooth muscles including those in the digestive tract and uterus are single-unit. Only some cells of single-unit smooth muscles receive autonomic innervation, but the ACh released by the axon can...

Problems with luminal stenosis

Although luminal stenosis percentage is the most commonly used clinical measure of plaque risk, it is not at all clear how to measure it in the first place, as evidenced by the two different systems adopted by the two major clinical trials in this area, ECST and NASCET. ECST determined the fractional stenosis by using the luminal diameter at the point of maximal stenosis at angiography as the numerator and the projected diameter of the artery at that same Fig. 1. Diagram showing the problems...

Palpation during inspiration

The liver, gallbladder, spleen and kidneys should be examined in turn during deep inspiration. The key to success is to keep the examining hand still and wait for the organ to descend. One common error is to begin palpation of the liver too close to the costal margin, thereby missing Place the hand flat on the abdomen with the lingers pointing upwards and position the sensing fingers index and middle lateral to the rectus muscle so that the fingertips lie on a line parallel to lhe expected...

Erection Emission and Ejaculation

Erection, accompanied by increases in the length and width of the penis, is achieved as a result of blood flow into the erectile tissues of the penis. These erectile tissues include two paired structures the corpora cavernosa located on the dorsal side of the penis, and one unpaired corpus spongiosum on the ventral Seminal vesicle Ejaculatory duct Prostate Figure 20.21 The organs of the male reproductive system. The male organs are seen here in a sagittal view. side fig. 20.22 . The urethra...

Tyrosine Kinase Second Messenger System

Insulin promotes glucose and amino acid transport and stimulates glycogen, fat, and protein synthesis in its target organs primarily the liver, skeletal muscles, and adipose tissue. These effects are achieved by means of a mechanism of action that is quite complex, and in some ways still incompletely understood. Nevertheless, it is known that insulin's mechanism of action bears similarities to the mechanism of action of other regulatory molecules known as growth factors. These growth factors,...

Neurilemma and Myelin Sheath

All axons in the PNS myelinated and unmyelinated are surrounded by a continuous, living sheath of Schwann cells, known as the neurilemma, or sheath of Schwann. The axons of the CNS, by contrast, lack a neurilemma Schwann cells are only found in the PNS . This is significant in terms of regeneration of damaged axons, as will be described shortly. Some axons in the PNS and CNS are surrounded by a myelin sheath. In the PNS, this insulating covering is formed by successive wrappings of the cell...

Maintenance of Upright Posture and Balance

The skeleton supporting the body is a system of long bones and a many-jointed spine that cannot stand erect against the forces of gravity without the support given by coordinated muscle activity. The muscles that maintain upright posture that is, support the body's weight against gravity are controlled by the brain and by reflex mechanisms that are wired into the neural networks of the brainstem and spinal cord. Many of the reflex pathways previously introduced for example, the stretch and...

Mechanism of Thyroid Hormone Action

As previously discussed, the major hormone secreted by the thyroid gland is thyroxine, or tetraiodothyronine T4 . Like steroid hormones, thyroxine travels in the blood attached to carrier proteins primarily to thyroxine-binding globulin, or TBG . The thyroid also secretes a small amount of triiodothyronine, or T3. The carrier proteins have a higher affinity for T4 than for T3, however, and, as a result, the amount of unbound or free T3 in the plasma is about ten times greater than the amount of...

Control Systems Involving the Hypothalamus and Pituitary

The pituitary gland, or hypophysis, lies in a pocket the sella turcica of the sphenoid bone at the base of the brain Figure 10-12 , just below the brain area called the hypothalamus. The pituitary is connected to the hypothalamus by the infundibulum, a stalk containing nerve fibers and small blood vessels. In adult human beings, the pituitary gland is composed of two adjacent lobes the anterior pituitary toward the front of the head and the posterior pituitary toward the back of the head each...

Varicellazoster Virus

Like the herpes simplex viruses, varicella-zoster virus VZV is an enveloped, dou-ble-standed, DNA virus of the herpesvirus family. VZV causes two distinct clinical syndromes. Primary exposure to VZV results in varicella chickenpox , a usually benign, highly contagious infection of children. Reactivation of latent VZV results in herpes zoster shingles , an illness most commonly seen in adults over the age of 45 yr. VZV is spread from person to person by direct contact, as an aerosol from skin...

Transport of Carbon Dioxide in Blood

In a resting person, metabolism generates about 200 ml of carbon dioxide per minute. When arterial blood flows through tissue capillaries, this volume of carbon dioxide diffuses from the tissues into the blood Figure 15-27 . Carbon dioxide is much more soluble in water than is oxygen, and so more dissolved carbon dioxide than dissolved oxygen is carried in blood. Even so, only a relatively small amount of blood carbon dioxide is transported in this way only 10 percent of the carbon dioxide...

Regulation of Insulin and Glucagon Secretion

Insulin and glucagon secretion is largely regulated by the plasma concentrations of glucose and, to a lesser degree, of amino acids. The alpha and beta cells, therefore, act as both the sensors and effectors in this control system. Since the plasma concentration of glucose and amino acids rises during the absorption of a meal and falls during fasting, the secretion of insulin and glucagon likewise fluctuates between the absorptive and postabsorptive states. These changes in insulin and...

Responses to Adrenergic Stimulation

Adrenergic stimulation by epinephrine in the blood and by norepinephrine released from sympathetic nerve endings has both excitatory and inhibitory effects. The heart, dilatory muscles of the iris, and the smooth muscles of many blood vessels are stimulated to contract. The smooth muscles of the bronchioles and of some blood vessels, however, are inhibited from contracting adrenergic chemicals, therefore, cause these structures to dilate. Since excitatory and inhibitory effects can be produced...

Diagnostic evaluation

The evaluation of a patient with lower extremity arterial occlusive disease starts with a detailed history and a complete physical examination 1 . A thorough pulse exam of both upper and lower extremities is of outmost importance. Absence of palpable pulses at any level indicates hemodynamically significant lesion s to the main artery proximal to that level. Thus, absence of palpable femoral pulses is suggestive of severe stenosis or occlusion of the ipsilateral iliac artery 2 . Hemodynamic...

Feedback Control of the Anterior Pituitary

In view of its secretion of releasing and inhibiting hormones, the hypothalamus might be considered the master gland. The chain of command, however, is not linear the hypothalamus and anterior pituitary are controlled by the effects of their own actions. In the endocrine system, to use an analogy, the general takes orders from the private. The hypothalamus and anterior pituitary are not master glands because their secretions are controlled by the target glands they regulate. Anterior pituitary...

Juvenile Myelomonocytic Leukemia

Incidence 1.2 per million children per year Median age at diagnosis 1.8 years 35 below 1 year of age, and only 4 above 5 years of age Male female ratio of 2 1 Association with neurofibromatosis type 1 NF-1 Children with NF-1 have more than a 200-fold increased risk of JMML. Fifteen percent of children with JMML have NF-1. Children with Noonan syndrome or trisomy 8 mosaicism are at increased risk of developing JMML. Most cases of neonates with Noonan syndrome with JMML-like presentation resolve...

Review Activities

Test Your Knowledge ofTerms and Facts 1. Which of these statements is false 2. a. Most of the total blood volume is contained in veins. b. Capillaries have a greater total surface area than any other type of vessel. c. Exchanges between blood and 3. tissue fluid occur across the walls d. Small arteries and arterioles present great resistance to blood flow. All arteries in the body contain oxygen-rich blood with the exception of The lub, or first heart sound, is b. the pulmonary semilunar valve....

Localized Inflammatory Response

The hallmarks of a localized acute inflammatory response, first described almost 2000 years ago, are swelling tumor , redness rubor , heat calor , pain dolor , and loss of function. Within minutes after tissue injury, there is an increase in vascular diameter vasodilation , resulting in an increase in the volume of blood in the area and a reduction in the flow of blood. The increased blood volume heats the tissue and causes it to redden. Vascular permeability also increases, leading to leakage...

Hypnosis And Psychoneuroimmunology

In light of current interest in psychoneuroimmunology and mind-body connections, a somewhat neglected area of hypnotherapy research of major theoretical and practical interest is the underlying neurophysiological processes that might mediate hypnosis in its contribution to immunomodulation. Interpretation of earlier research is hindered by methodological shortcomings these shortcomings are now being addressed and overcome with the most recent wave of research. It is suggested that the reduction...

Atrial Stretch Reflexes

In addition to the baroreceptor reflex, several other reflexes help to regulate blood pressure. The reflex control of ADH release by osmoreceptors in the hypothalamus and the control of an-giotensin II production and aldosterone secretion by the juxta- glomerular apparatus of the kidneys have been previously discussed. Antidiuretic hormone and aldosterone increase blood pressure by increasing blood volume, and angiotensin II stimulates vasoconstriction to cause an increase in blood pressure....

Physiopathology of Hypogonadism

Acromegaly is a disease characterized by the excessive production of growth hormone GH . More than 99 of cases of acromegaly result from a tumor of the pituitary gland secreting either GH or both GH and PRL. Gangliocytomas of the hypothalamus or pituitary and ectopic neuroendocrine tumors secreting GH-releasing hormone GHRH account for less than 1 33 . Hypogonadism has been reported in 49 to 70 of patients with acromegaly 31,34 . Secretion of PRL by the tumor, together with GH or stalk...

Normal Mri Rotator Cuff

The superior and inferior labra are visualized best on coronal oblique images, whereas the anterior and posterior labra are seen best on axial images Figs. 14 and 15 . A labral tear is diagnosed when an irregular line of fluid or intra-artic-ular contrast tracks into the labral substance or between the labrum and the glenoid articular cartilage Fig. 16 . When a labral tear extends through the joint capsule, a paralabral cyst may develop in an extra-articular location. The cyst may be the most...

Velocity of Capillary Blood Flow

Figure 14-44 illustrates a simple mechanical model of a series of 1-cm-diameter balls being pushed down a single tube that branches into narrower tubes. Although each tributary tube has a smaller cross section than the wide tube, the sum of the tributary cross sections is three times greater than that of the wide tube. Let us assume that in the wide tube each ball moves 3 cm min. If the balls are 1 cm in diameter and they move two abreast, six balls leave the wide tube per minute and enter the...

Effect of Exercise and High Altitude on Respiratory Function

The arterial blood gases and pH do not significantly change during moderate exercise because ventilation increases during exercise to keep pace with the increased metabolism. Adjustments are also made at high altitude in both the control of ventilation and the oxygen transport ability of the blood to permit adequate delivery of oxygen to the tissues. Figure 16.41 The effect of exercise on arterial blood gases and pH. Notice that there are no consistent or significant changes in these...

Hormones That Bind to Nuclear Receptor Proteins

Unlike the water-soluble hormones, the lipophilic steroid and thyroid hormones do not travel dissolved in the aqueous portion of the plasma rather, they are transported to their target cells attached to plasma carrier proteins. These hormones must then dissociate from their carrier proteins in the blood in order to pass through the lipid component of the plasma membrane and enter the target cell, within which their receptor proteins are located fig 11.4 . The receptors for the lipophilic...