Q: Which equation best represents the negative feedback control of thyroid hormone secretion?

$\mathrm{TRH} \rightarrow \mathrm{TSH} \rightarrow \mathrm{Thyroid\ Hormone} \rightarrow \text{inhibition of TRH and TSH}$

Question 1

Which of the following best describes the difference between steroid and peptide hormones in terms of their mechanism of action?

Accepted Answer

Steroid hormones are lipid-soluble and pass through cell membranes to bind intracellular receptors, while peptide hormones are water-soluble and bind to membrane receptors.

Question 2

A patient presents with excessive urination and constant thirst. Lab results show low levels of antidiuretic hormone (ADH). Which condition is most likely?

Accepted Answer

Diabetes insipidus

Question 3

Which hormone is secreted by the adrenal cortex in response to ACTH and is associated with long-term stress?

Accepted Answer

Cortisol

Question 4

A person with untreated diabetes mellitus experiences polyuria and excessive hunger. Why do they feel hungry despite high blood glucose?

Accepted Answer

Their cells cannot use glucose due to lack of insulin, so energy is not available.

Question 5

Which hormone is released by the posterior pituitary in response to uterine stretching and is involved in labor and mate bonding?

Accepted Answer

Oxytocin

Question 6

If a patient has a pituitary tumor causing excess ACTH secretion, which adrenal hormone will be most elevated, and what is the likely disease?

Accepted Answer

Cortisol; Cushing's disease

Question 7

Which hormone is secreted by the pancreas in response to elevated blood glucose and promotes glucose uptake by cells?

Accepted Answer

Insulin

Question 8

A patient has low blood calcium levels. Which hormone will be secreted to restore calcium homeostasis, and what is its primary action?

Accepted Answer

Parathyroid hormone; stimulates release of Ca$^{2+}$ from bone

Question 9

Which of the following is an example of negative feedback in the endocrine system?

Accepted Answer

High blood glucose stimulates insulin release, which lowers blood glucose, reducing further insulin secretion.

Question 10

Which hormone is secreted by the anterior pituitary and stimulates the thyroid gland to release thyroid hormones?

Accepted Answer

Thyroid-stimulating hormone (TSH)

Question 11

A patient with Grave's disease produces antibodies that mimic TSH. What is the expected effect on thyroid hormone levels?

Accepted Answer

Thyroid hormone levels will increase, causing hyperthyroidism.

Question 12

Which hormone is secreted by the pineal gland and regulates sleep/wake cycles?

Accepted Answer

Melatonin

Question 13

Which hormone is secreted by the adrenal medulla in response to sympathetic nervous system activation and increases heart rate and blood pressure?

Accepted Answer

Epinephrine

Question 14

Which hormone is secreted by the anterior pituitary and stimulates ovarian follicle maturation and sperm production?

Accepted Answer

Follicle-stimulating hormone (FSH)

Question 15

Which hormone is secreted in response to low blood glucose and promotes glycogen breakdown and glucose release into the blood?

Accepted Answer

Glucagon

Question 16

A patient with Addison's disease has low levels of which adrenal cortex hormone, and what is a common symptom?

Accepted Answer

Aldosterone; dehydration and low blood pressure

Question 17

Which hormone is secreted by parafollicular cells of the thyroid gland and lowers blood calcium levels?

Accepted Answer

Calcitonin

Question 18

Which equation best represents the negative feedback control of thyroid hormone secretion?

Accepted Answer

$\mathrm{TRH} ightarrow \mathrm{TSH} ightarrow \mathrm{Thyroid\ Hormone} ightarrow 	ext{inhibition of TRH and TSH}$

Question 19

Which hormone is secreted by the anterior pituitary and promotes milk production in the mammary glands?

Accepted Answer

Prolactin

Question 20

Which of the following best explains why steroid hormones have longer-lasting effects than peptide hormones?

Accepted Answer

Steroid hormones alter gene expression, leading to sustained changes in protein synthesis.

Endocrine System: Structure, Function, and Hormonal Regulation

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