Question 1

Which hormone is primarily responsible for increasing blood calcium levels when they fall below $$8.5\ \mathrm{mg/dL}$$, and what is one of its main actions?

Accepted Answer

Parathyroid hormone (PTH); it increases calcium reabsorption in the kidneys

Question 2

A patient presents with a blood calcium level of $$12\ \mathrm{mg/dL}. $$Which physiological response is most likely to occur?

Accepted Answer

Calcitonin secretion from the thyroid gland increases

Question 3

Which of the following best describes the role of calcitriol in calcium homeostasis?

Accepted Answer

It increases calcium reabsorption in the kidneys and absorption in the intestines

Question 4

A compound (open) fracture is characterized by which of the following?

Accepted Answer

The bone punctures the skin, increasing the risk of infection

Question 5

During fracture repair, what is the correct sequence of events following the initial break?

Accepted Answer

Hematoma forms, osteoblasts invade, cartilage callus forms, bony callus forms

Question 6

Which of the following is NOT a function of calcium in the human body?

Accepted Answer

Synthesis of hemoglobin

Question 7

If a patient has a disease that causes excessive bone resorption, which hormone is most likely deficient or not functioning properly?

Accepted Answer

Calcitonin

Question 8

Which of the following minerals is NOT stored in significant amounts in bone?

Accepted Answer

Iron

Question 9

A pathological fracture is best described as:

Accepted Answer

A fracture that occurs due to underlying disease or spontaneous bone weakness

Question 10

Which process is responsible for replacing the cartilage callus with bone during fracture repair?

Accepted Answer

Endochondral ossification

Question 11

If blood calcium levels fluctuate by more than $$30	ext{–}35\%$$, what is the likely consequence?

Accepted Answer

It can be lethal

Question 12

Which of the following best explains why bone is considered a dynamic tissue in relation to calcium homeostasis?

Accepted Answer

Bone constantly exchanges calcium with the blood in response to hormonal signals

Question 13

A patient with chronic kidney disease is likely to have problems with which aspect of calcium regulation?

Accepted Answer

Decreased production of calcitriol, leading to reduced calcium absorption in the intestines

Question 14

Which of the following statements about the hormonal regulation of blood calcium is correct?

Accepted Answer

Parathyroid hormone (PTH) increases blood calcium by stimulating osteoclasts and increasing kidney reabsorption

Question 15

During the repair of a bone fracture, which cell type is primarily responsible for cleaning up debris at the fracture site?

Accepted Answer

Phagocytes and osteoclasts

Question 16

Which of the following best describes the effect of calcitonin on the kidneys?

Accepted Answer

It suppresses calcium reabsorption, leading to increased calcium excretion

Question 17

A patient with a closed fracture would most likely present with which of the following?

Accepted Answer

No break in the skin at the fracture site

Question 18

Which of the following is a correct multi-step sequence for increasing blood calcium levels in response to hypocalcemia?

Accepted Answer

Parathyroid glands release PTH → increased osteoclast activity → increased kidney reabsorption of calcium → increased calcitriol production → increased intestinal absorption of calcium

Question 19

Which of the following would most likely occur if the parathyroid glands were surgically removed?

Accepted Answer

Blood calcium levels would decrease due to lack of PTH

Question 20

Which of the following best explains why a compound fracture has a higher risk of infection than a closed fracture?

Accepted Answer

The bone is exposed to the external environment through the skin

Bone Mineral Homeostasis, Hormonal Regulation, and Fracture Repair

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