Question 1

Which of the following best describes the structural unit of compact bone, and what is its primary function?

Accepted Answer

The osteon; it provides strength and allows for the passage of blood vessels and nerves.

Question 2

During bone remodeling, which hormone increases blood calcium levels by stimulating osteoclast activity?

Accepted Answer

Parathyroid hormone (PTH)

Question 3

A patient is diagnosed with sickle-cell anemia. Which of the following best explains the underlying cause and a major consequence of this condition?

Accepted Answer

A genetic mutation in hemoglobin causes RBCs to become rigid and sickle-shaped, leading to impaired oxygen transport and increased risk of vessel blockage.

Question 4

Which of the following best describes the difference between compact and spongy bone?

Accepted Answer

Compact bone is dense and forms the outer layer of bones, while spongy bone is porous and found at the ends of long bones.

Question 5

Which of the following correctly matches the type of joint with its example?

Accepted Answer

Synovial joint – knee

Question 6

A muscle contraction is initiated when calcium ions bind to which protein, and what is the immediate effect?

Accepted Answer

Troponin; it causes tropomyosin to move, exposing binding sites on actin.

Question 7

Which of the following best describes the role of acetylcholine at the neuromuscular junction?

Accepted Answer

It transmits the nerve impulse from the motor neuron to the muscle fiber, triggering muscle contraction.

Question 8

Which of the following is a correct sequence of blood flow through the heart starting from the vena cava?

Accepted Answer

Vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta

Question 9

A patient with type A- blood receives a transfusion of AB+ blood. Which of the following best describes the likely outcome and the immunological basis?

Accepted Answer

Agglutination will occur because the recipient's anti-B and anti-Rh antibodies will attack the donor's B and Rh antigens.

Question 10

Which of the following best explains why veins have valves, but arteries generally do not?

Accepted Answer

Veins carry blood under lower pressure and against gravity, so valves prevent backflow.

Question 11

Which of the following best describes the function of the lymphatic system?

Accepted Answer

It returns excess tissue fluid to the bloodstream and provides immune defense.

Question 12

Which of the following is a correct description of the cardiac cycle?

Accepted Answer

Systole is the contraction phase when the ventricles pump blood, and diastole is the relaxation phase when the chambers fill with blood.

Question 13

Which of the following best describes the difference between active and passive immunity?

Accepted Answer

Active immunity involves the body producing its own antibodies, while passive immunity involves receiving antibodies from another source.

Question 14

A child is born to an Rh-negative mother and an Rh-positive father. The mother did not receive RhoGAM during her first pregnancy. Which of the following best explains the risk to the second child?

Accepted Answer

The mother's immune system may produce anti-Rh antibodies that cross the placenta and destroy the RBCs of an Rh-positive fetus, causing hemolytic disease of the newborn.

Question 15

Which of the following best describes the role of MHC (Major Histocompatibility Complex) molecules in the immune system?

Accepted Answer

They present antigens on the surface of cells for recognition by T lymphocytes.

Question 16

Which of the following is a correct sequence of events in blood clot formation?

Accepted Answer

$$	ext{Prothrombin activator} ightarrow 	ext{Prothrombin} ightarrow 	ext{Thrombin} ightarrow 	ext{Fibrinogen} ightarrow 	ext{Fibrin}$$

Question 17

Which of the following best describes the difference between an autoimmune disorder and an allergy?

Accepted Answer

An autoimmune disorder is when the immune system attacks the body's own cells, while an allergy is an overreaction to a harmless foreign substance.

Question 18

Which of the following best explains why capillaries are the primary site of exchange between blood and tissues?

Accepted Answer

Capillaries have thin walls (one cell thick) and a large surface area, allowing efficient diffusion of gases, nutrients, and wastes.

Question 19

A person is exposed to a pathogen for the first time and develops symptoms after several days. Upon a second exposure years later, they do not get sick. Which of the following best explains this phenomenon?

Accepted Answer

The secondary immune response is faster and stronger due to memory cells produced during the primary response.

Human Biology Study Guide: Skeleton, Muscles, Blood, Cardiovascular, and Immune Systems

Study Guide - Practice Questions

Study Guide - Flashcards