Animal Cell Parts

After study of this chapter you should be able to:

1. Describe the main parts of a cell.

2. Label a diagram of a typical cell.

3. Name and give the functions of the four basic types of tissues in the body.

4. Define basic terms pertaining to the structure and function of body tissues.

5. Recognize and use roots and suffixes pertaining to cells, tissues, and organs.

6. Analyze two case studies pertaining to cells and tissues.

The Cell

The body can be studied from its simplest to its most complex level, beginning with the cell, the basic unit of living organisms (Fig. 4-1). Cells carry out metabolism, the sum of all of the physical and chemical activities that occur in the body. Providing the energy for metabolic reactions is the chemical ATP (adenosine triphosphate), commonly described as the energy compound of the cell. The main categories of organic compounds in the body are:

• Proteins, which include the enzymes, some hormones, and structural materials.

• Carbohydrates, which include sugars and starches. The main carbohydrate is the sugar glucose, which circulates in the blood to provide energy for the cells.

• Lipids, which include fats. Some hormones are derived from lipids, and adipose (fat) tissue is designed to store lipids.

Within the cytoplasm that fills the cell are subunits called organelles, each with a specific function. The main cell structures are named and described in Display 4-1.

All body functions derive from the activities of billions of specialized cells. The nucleus is the control region of the cell. It contains the chromosomes, which carry genetic information (Fig. 4-2). Each human

Nucleus

Animal Cell Medical Terminology
FIGURE 4-1. Diagram of a typical animal cell showing the main organelles. (Reprinted with permission from Cohen BJ, Wood DL. Memmler's The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.)

DISPLAY 4-1 Cell Structures

NAME

DESCRIPTION

FUNCTION

plasma membrane

outer layer of the cell; composed mainly of lipids and proteins

limits the cell; regulates what enters and leaves the cell

cytoplasm

colloidal suspension that fills cell

holds cell contents

nucleus

large, dark-staining body near the center of the cell; composed of DNA and proteins

contains the chromosomes with the genes (the hereditary material that directs all cell activities)

nucleolus

small body in the nucleus; composed of RNA, DNA, and protein

needed for protein manufacture

endoplasmic reticulum (ER)

network of membranes in the cytoplasm

used for storage and transport; holds ribosomes

ribosomes

small bodies attached to the ER; composed of RNA and protein

manufacture proteins

mitochondria

large organelles with folded membranes inside

convert energy from nutrients into ATP

Golgi apparatus

layers of membranes

put together special substances such as mucus

lysosomes

small sacs of digestive enzymes

digest substances within the cell

centrioles

rod-shaped bodies (usually two) near the nucleus

help separate the chromosomes in cell division

cilia

short, hairlike projections from the cell

create movement around the cell

flagellum

long, whiplike extension from the cell

moves the cell

FIGURE 4-2. Human chromosomes. (Reprinted with permission from Cohen BJ, Wood DL. Memmler's The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.)

Medical Terminology Body Parts Animal

FIGURE 4-2. Human chromosomes. (Reprinted with permission from Cohen BJ, Wood DL. Memmler's The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.)

Meiosis Memmler
FIGURE 4-3. The stages in cell division (mitosis). (Reprinted with permission from Cohen BJ, Wood DL. Memmler's The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.)

cell, except for the sex cells, contains 46 chromosomes. The chromosomes are composed of a complex organic substance, DNA (deoxyribonucleic acid), which is organized into separate units called genes. Genes control the formation of enzymes, the catalysts needed for metabolic reactions. To help manufacture enzymes, the cells use a compound called RNA (ribonucleic acid), which is chemically related to DNA.

When a body cell divides, by the process of mitosis, the chromosomes are doubled and then equally distributed to the two daughter cells (Fig. 4-3). Sex cells (egg and sperm) divide by another process (meiosis) that halves the chromosomes in preparation for fertilization.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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Responses

  • Stephanie
    Which structure in a cell contains the cell's genetic information with the diagram?
    6 years ago
  • lavinia
    What are the parts of animal cell?
    6 years ago
  • SAM
    What is the parts of animal cells in a sentences?
    6 years ago
  • mirin
    Where is the chromosomes in the animal cell?
    6 years ago
  • gilly brandagamba
    What are the parts of an animal cell called?
    6 years ago
  • togo
    What are the four structures of a typical animal cell?
    3 months ago

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