Question 1

Which of the following best describes the concept of homeostasis in the human body?

Accepted Answer

The maintenance of a stable internal environment despite external changes.

Question 2

A patient is found to have a higher concentration of potassium ($$K^+) $$inside their cells and a higher concentration of sodium ($$Na^+) $$outside their cells. This distribution is an example of which type of disequilibrium?

Accepted Answer

Chemical disequilibrium

Question 3

Which of the following best explains why water moves from an area of low solute concentration to an area of high solute concentration across a semipermeable membrane?

Accepted Answer

Osmosis, driven by the osmotic gradient

Question 4

Which of the following is a function of the buffer zone between the outside world and most of the cells of the body?

Accepted Answer

It helps maintain homeostasis by regulating the composition of extracellular fluid.

Question 5

A researcher is studying the movement of glucose across a cell membrane. She observes that glucose moves down its concentration gradient but requires a specific membrane protein to do so. Which type of transport is this?

Accepted Answer

Facilitated diffusion

Question 6

Which of the following best describes the difference between the intracellular fluid (ICF) and extracellular fluid (ECF) in terms of ion composition?

Accepted Answer

ICF has higher potassium ($$K^+) $$and lower sodium ($$Na^+) $$than ECF.

Question 7

A patient is given an intravenous solution that is hypertonic relative to their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

Water will leave the cells, causing them to shrink (crenate).

Question 8

Which of the following best describes the role of negative feedback in homeostasis?

Accepted Answer

It counteracts a change in a variable, returning the system to its set point.

Question 9

Which of the following is an example of a positive feedback mechanism in the human body?

Accepted Answer

Uterine contractions during childbirth

Question 10

A cell is placed in a solution and water moves into the cell, causing it to swell. Which term best describes the solution relative to the cell?

Accepted Answer

Hypotonic

Question 11

Which of the following best describes the function of the sodium-potassium pump ($$Na^+/K^+-$$ATPase) in maintaining cellular homeostasis?

Accepted Answer

It actively transports $$3$$ $$Na^+$$ ions out of the cell and $$2$$ $$K^+$$ ions into the cell, using ATP.

Question 12

Which of the following statements about signal transduction is correct?

Accepted Answer

A first messenger binds to a membrane receptor, which activates a second messenger inside the cell.

Question 13

A patient with low blood calcium is found to have increased secretion of parathyroid hormone (PTH). Which of the following best explains this response?

Accepted Answer

PTH increases blood calcium by stimulating bone resorption and increasing calcium reabsorption in the kidneys.

Question 14

Which of the following best describes the difference between a ligand and an antagonist in cell signaling?

Accepted Answer

A ligand binds to a receptor and triggers a response, while an antagonist binds but does not trigger a response.

Question 15

A patient is diagnosed with hypothyroidism. Which of the following symptoms is most likely to be observed?

Accepted Answer

Fatigue, weight gain, and sensitivity to cold

Question 16

Which of the following best explains why facilitated diffusion is faster than simple diffusion for certain molecules?

Accepted Answer

Facilitated diffusion uses specific protein channels or carriers that speed up the movement of molecules across the membrane.

Question 17

Which of the following is a correct example of a negative feedback loop in the human body?

Accepted Answer

Increased blood glucose stimulates insulin release, which lowers blood glucose.

Question 18

Which of the following best describes the function of the hypothalamic-pituitary-adrenal (HPA) axis?

Accepted Answer

It regulates the release of cortisol in response to stress.

Question 19

A patient is found to have a mutation in a gene encoding a membrane receptor. The receptor can still bind its ligand, but no cellular response occurs. Which of the following best explains this observation?

Accepted Answer

The receptor is likely bound by an antagonist, preventing signal transduction.

Question 20

Which of the following best describes the role of aquaporins in the cell membrane?

Accepted Answer

They facilitate the rapid movement of water across the membrane.

Anatomy & Physiology: Homeostasis, Cell Physiology, and Endocrine System Study Guide

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