Introduction to Cell Physiology

1.

A researcher is studying chromosomal disorders. What part of the human cell would the researcher be interested in studying?
A)
Cytoplasm
B)
Membrane
C)
Nucleus
D)
Organelles
Ans:
C

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The nucleus of a cell contains all of the genetic material that is necessary for cell reproduction. The nucleus also contains genes or sequences of deoxyribonucleic acid (DNA). Genes are responsible for the formation of messenger ribonucleic acid (mRNA) and transcription RNA, which are involved in production of proteins unique to the cells. This is the area where chromosomal disorders originate. The cell cytoplasm lies within the cell membrane and is the site of activities of cellular metabolism and special cellular functions. The organelles are contained within the cytoplasm and are structures with specific functions. They include the mitochondria, endoplasmic reticulum, free ribosomes, Golgi apparatus, and lysosomes. The membrane is a thin barrier, which separates the intracellular fluid from the extracellular fluid and is essential for cellular integrity; it also maintains cell homeostasis.

2.

Which of these body cells has the greatest number of mitochondria?
A)
Tibia bone cells
B)
Breast tissue
C)
Cardiac muscle
D)
Subcutaneous skin
Ans:
C

Feedback:

Mitochondria are very abundant in cells that consume energy. The cardiac muscle cells, which must work continually to keep the heart contracting, contain a great number of mitochondria. Milk-producing cells in breast tissue, which are normally dormant, contain very few. Cells of bone and of subcutaneous tissue do not consume a great deal of energy; therefore, they have smaller numbers of mitochondria than cardiac muscle.

3.

When hormones, formed within the cell, move across the cell membrane, the process is called what?
A)
Endocytosis
B)
Exocytosis
C)
Phagocytosis
D)
Pinocytosis
Ans:
B

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Exocytosis is the movement of substances such as waste products, hormones, and neurotransmitters out of the cell. Pinocytosis is the movement of nutrients and needed substances into the cell through specific receptors on the cell surface. Phagocytosis involves the destruction of engulfed proteins or bacteria. Endocytosis involves incorporation of material into the cell.

4.

What substances move freely in and out of a cell by diffusion?
A)
Electrolytes
B)
Enzymes
C)
Hormones
D)
Proteins
Ans:
A

Feedback:

Sodium, potassium, calcium, carbonate, oxygen, bicarbonate, and water move freely in and out of cells. These substances move through channels or pores in the cell membrane through movement from a region of higher concentration to a region of lower concentration. Hormones, enzymes, and proteins are considered carriers. If a substance cannot move freely on its own, it may attach itself to another carrier to be diffused.

5.

There can be interference with cancer chemotherapy in what phase of the cell cycle?
A)
G0 phase
B)
G1 phase
C)
G2 phase
D)
S phase
Ans:
A

Feedback:

During the G0 phase, the cell is stable. Cells in this phase can interfere with cancer chemotherapy because these drugs usually work on actively dividing cells, leaving resting cells mostly untouched. When the resting cells are stimulated to become active and regenerate, the cancer can return. This is the reason that cancer chemotherapy regimens are complicated and extended over a period of time. In the G1 phase, a cell is stimulated to emerge from its resting phase. During this time, the cell synthesizes the substances needed for DNA formation. The S phase involves the actual synthesis of DNA, and during the G2 phase, the cell produces all the substances that are required for the manufacture of the mitotic spindles.

6.

The pharmacology instructor is discussing the histocompatibility of the cell. What is the importance of a cell’s histocompatibility antigen?
A)
It reproduces cells when other cells die.
B)
It recognizes cells as self-cells that belong in the body.
C)
The antigen produces antibodies to viral invaders.
D)
The antigen stimulates the production of white blood cells.
Ans:
B

Feedback:

The histocompatibility antigens are proteins that are seen on the top of the cell membrane. T cells use these antigens as the identifying proteins that identify a cell as a self-cell. If these antigens are not present on a cell membrane, the T cells will destroy that cell, determining that it is foreign. The histocompatibility antigens are not involved in reproduction. They do not produce antibodies nor do they stimulate white blood cell production.

7.

A patient on the unit has a deep decubitus ulcer. The family asks why the nurse debrides the ulcer and removes the dead cells. What is the nurse’s best response to explain to the family why debridement is performed?
A)
The lysosomes released by the dead cells in the area continue to kill other cells, destroying more tissue.
B)
The dead cells no longer contain histocompatible antigens causing a greater inflammatory response.
C)
Removing dead tissue forces oxygen to enter the damaged cells to regenerate them and to promote healing.
D)
The doctor ordered the procedure to be performed so it is done the way it is ordered because orders are always followed.
Ans:
A

Feedback:

When a cell dies, its cell membrane ruptures and the lysosomes release lysozymes, which dissolve protein. When many cells die, lysozymes accumulate and dissolve the proteins that the dead cells leave behind, but the lysozymes also destroy the cell membrane of healthy cells in the area. Those cells then die, releasing lysozymes, which destroy more cells, and a vicious cycle occurs. A decubitus ulcer is an area of many dead cells, which are killing healthy cells. The area needs to be scraped clean to remove the dead cells so that the lysozymes will stop destroying healthy cells and allow oxygen to return to the area through the capillary bed, which allows healing to occur. Many treatments exist for decubitus ulcers, all of which depend on the return of blood flow to the area and removal of the dead tissue. No procedure should ever be performed only because it was ordered. The nurse should understand why each procedure is needed.

8.

A patient is extremely dehydrated from vomiting and diarrhea causing his or her blood to become hypertonic. What effect does the nurse expect this will have on the red blood cells?
A)
They will swell and eventually rupture.
B)
Red blood cells will migrate to the bone narrow.
C)
The cells will shrink and shrivel, decreasing their oxygen-carrying ability.
D)
The red cells will precipitate out of circulation.
Ans:
C

Feedback:

A hypertonic solution will draw the water out of the red blood cell, causing it to shrink and shrivel, decreasing the oxygen carrying ability of the red blood cell. A hypotonic solution would result in water moving into the red blood cell, causing it to swell and burst. Red blood cells will not migrate back to the bone marrow or precipitate out of circulation.

9.

The nurse is caring for four patients. Which patient would the nurse expect to have a faster recovery period based only on the process of mitosis?
A)
A 32-year-old female patient who had surgery for ulcerated colitis
B)
A 72-year-old man who had surgery for colon cancer
C)
A 28-year-old woman who had breast reduction surgery
D)
A 65-year-old man who had surgery for breast cancer
Ans:
A

Feedback:

Cells lining the GI tract reproduce very quickly (72 hours) compared with breast tissue, which takes 2 to 3 months to reproduce. The older the person is, the longer it will take for recovery due to the aging process that reduces rate of circulation of blood cells carrying oxygen to and from cells.

10.

When chemotherapeutic agents interfere with cellular physiology, it results in what?
A)
Cellular death or alterations
B)
Diffusion
C)
Endocytosis
D)
Homeostasis
Ans:
A

Feedback:

Drugs may alter the cell membrane, causing the cell to rupture and die or they may deprive the cell of certain nutrients, altering the proteins that the cell produces. This could interfere with normal cell functioning and cell division. Diffusion is the movement of a substance from a region of higher concentration to a region of lower concentration. Endocytosis involves gathering of material into a cell. Homeostasis refers to keeping the cytoplasm stable within the cell membrane. Diffusion, endocytosis, and homeostasis are not the result of chemotherapeutic agents but may be impacted by the agent.

11.

When learning about the physiology of the human body, a student would learn that cellular metabolism takes place where?
A)
Organelles
B)
Mitochondria
C)
Endoplasmic reticulum
D)
Cytoplasm
Ans:
D

Feedback:

The cell cytoplasm lies within the cell membrane and outside the nucleus and is the site of activities of cellular metabolism and special cellular functions. Organelles, mitochondria, and endoplasmic reticulum are all part of the cytoplasm of the cell and each has a specific function that contributes to cellular function.

12.

What is the function of the rough endoplasmic reticulum (ER) within a cell?
A)
Produces proteins
B)
Combines protein with other components of the cytoplasm
C)
Exports protein from the cell
D)
Destroys ribosomes
Ans:
A

Feedback:

Many granules that contain enzymes and ribosomes, which produce protein, are scattered over the surface of the rough endoplasmic reticulum. Production of proteins, phospholipids, and cholesterol takes place in the rough endoplasmic reticulum. The rough ER segregates (rather than combines) these proteins from other components of the cytoplasm and modifies their structure for a specific function. Rough ER does not transport anything through the cell membrane. Rough ER is studded with ribosomes; it does not destroy them.

13.

What is one purpose of the Golgi apparatus?
A)
Produces bile
B)
Prepares hormones or other substances for secretion-producing excretory granules
C)
Stimulates production of new red blood cells
D)
Produces small carbohydrate molecules
Ans:
B

Feedback:

The Golgi apparatus is a series of flattened sacs that may be part of the endoplasmic reticulum. These structures prepare hormones or other substances for secretion by processing them and packaging them in vesicles to be moved to the cell membrane for excretion from the cell. Golgi bodies do not produce bile. They produce secretory, not excretory, granules and they produce large carbohydrate molecules rather than small ones.

14.

Mitochondria produce energy in the form of what?
A)
Deoxyribonucleic acid (DNA)
B)
Red blood cells
C)
Lactic acid
D)
Adenosine triphosphate (ATP)
Ans:
D

Feedback:

Mitochondria are rod-shaped “power plants” within each cell that produce energy in the form of ATP, which allows the cell to function. Red blood cells and DNA are not formed in the mitochondria. If oxygen is not available, lactic acid builds up as a by-product of cellular respiration. Lactic acid leaves the cell and is transported to the liver for conversion to glycogen and carbon dioxide.

15.

The physiology instructor is explaining cell death to the nursing students. The instructor explains that what organelle digests worn or damaged sections of a cell when the cell dies?
A)
Golgi apparatus
B)
Lysosomes
C)
Endoplasmic reticulum
D)
Mitochondria
Ans:
B

Feedback:

Lysosomes are membrane-covered organelles that contain specific digestive enzymes that can break down proteins, nucleic acids, carbohydrates, and lipids. They are responsible for digesting worn or damaged sections of a cell when the membrane ruptures and the cell dies. The Golgi apparatus prepares substances for secretion by processing and packaging them in vehicles to move through the cell membrane. The endoplasmic reticulum provides a large surface for chemical reactions within the cell. Mitochondria are the power plants of the cell.

16.

What is the function of the mitochondria within the cell?
A)
Convert small substances into energy
B)
Convert hormones into secretory substances
C)
Produce energy in the form of adenosine triphosphate (ATP)
D)
Move electrolytes into and out of a cell
Ans:
C

Feedback:

Mitochondria are rod-shaped organelles that produce energy in the form of ATP for use by cells. They do not convert small substances into energy; they do not convert hormones into secretory substances; and they do not move electrolytes into and out of a cell.

17.

Two types of ribosomes exist within a cell. Ribosomes that are not bound to the endoplasmic reticulum exist throughout the cytoplasm of the cell and produce proteins with what purpose?