Endocrine System Quiz: Parathyroid and Thyroid

Questions and Answers

What primary function does parathormone (PTH) serve in calcium regulation?

Increases bone mass

Decreases intestinal calcium absorption

Stimulates osteoclast activity to release calcium (correct)

Inhibits renal calciuresis

Which cell type in the parathyroid gland is primarily responsible for the secretion of parathormone?

Follicular cells

Clear cells

Chief cells (correct)

C cells

In terms of the histology of the thyroid gland, which of the following characteristics is associated with 'more active' thyroid follicles?

Paler staining with numerous vacuoles

Larger size and darker staining (correct)

Smaller size with fewer vacuoles

Presence of parafollicular cells

Which zone of the adrenal cortex is primarily involved in the production of mineralocorticoids?

Zona glomerulosa Signup and view all the answers

How does parathormone (PTH) affect renal function?

Enhances renal reabsorption of calcium Signup and view all the answers

Which of the following best describes the adrenal medulla?

Primarily produces catecholamines Signup and view all the answers

Which hormone opposes the action of parathyroid hormone in regulating calcium levels?

Calcitonin Signup and view all the answers

Which mechanism explains the action of calcitonin in the regulation of calcium levels in the body?

Decreases the activity of osteoclasts Signup and view all the answers

Which of the following statements about follicular cells in the thyroid gland is accurate?

They are responsible for the conversion of iodinated thyroglobulin to active thyroxine. Signup and view all the answers

What role does T3 play in the body's metabolic processes?

Increases protein synthesis and glycogen breakdown Signup and view all the answers

Which cell type is responsible for the secretion of thyroid hormones in the thyroid gland?

Cuboidal follicular cells Signup and view all the answers

How does T3 influence cardiovascular function?

Increases heart rate and myocardial contraction force Signup and view all the answers

What is the primary secretory product of parafollicular 'C' cells in the thyroid gland?

Calcitonin Signup and view all the answers

What is the effect of elevated TSH secretion on thyroid gland function?

It stimulates thyroid follicular cells to produce more thyroid hormones. Signup and view all the answers

What primary function does glucagon serve in the body's glucose regulation?

Stimulates glycogen breakdown Signup and view all the answers

Which cells in the digestive system are associated with secreting hormones like gastrin and ghrelin?

Enteroendocrine cells Signup and view all the answers

What is the role of leptin secreted by unilocular adipocytes?

Signals to the hypothalamus to regulate energy homeostasis Signup and view all the answers

Which of the following hormones stimulates the secretion of gastric juice?

Gastrin Signup and view all the answers

What is a key feature of unilocular adipocytes in their endocrine function?

They produce leptin to influence feeding behavior Signup and view all the answers

The enteroendocrine cell's function can be categorized under which of the following terms?

Diffuse neuroendocrine cells Signup and view all the answers

What is the primary mechanism by which the body regulates calcium levels?

Through parathyroid hormone function Signup and view all the answers

What is the primary function of glucocorticoids produced by the zona fasciculata?

Decrease pain sensitivity Signup and view all the answers

Which of the following cell types is found in the zona reticularis?

Polyhedral cells Signup and view all the answers

Which of the following best describes the arrangement of cells in the zona fasciculata?

Radiating columns bundled as fascicles Signup and view all the answers

What is a key effect of angiotensin II triggered by low blood pressure?

Na/K ATPase expression in the distal tubule Signup and view all the answers

What is the primary hormone synthesized in the zona fasciculata?

Cortisol Signup and view all the answers

What hormonal action relates to increased gluconeogenesis in response to stress?

Increased cortisol release Signup and view all the answers

Which condition is NOT typically associated with the effects of glucocorticoids?

Increased sensitivity to pain Signup and view all the answers

What is the effect of glucocorticoids on muscle tissue?

Inhibits protein synthesis Signup and view all the answers

Which of the following are considered functions of small amounts of androgens produced in the zona reticularis?

Support of secondary sexual characteristics Signup and view all the answers

Study Notes

Parafollicular Cells and Parathyroid Gland

Parafollicular cells (C cells) are located in the thyroid gland and secrete calcitonin.
Calcitonin lowers plasma calcium levels by decreasing osteoclast activity, leading to increased calcium storage in bones and enhanced renal excretion.
Chief cells in the parathyroid gland produce parathormone (PTH) in response to low blood calcium levels.
PTH increases blood calcium by stimulating osteoclasts, enhancing intestinal absorption, and promoting renal resorption of calcium.

Thyroid Gland Functions

The thyroid gland is regulated by thyroid-stimulating hormone (TSH).
Follicular cells in the thyroid secrete thyroglobulin, which combines with iodine to produce thyroid hormones (T3 and T4).
T3 increases basal metabolic rate, thermogenesis, gluconeogenesis, and the heart's force and rate of contraction.
T3 promotes protein synthesis, glycogen breakdown, and lipolysis through increased LDL receptors.

Adrenal Glands Structure and Hormones

Composed of an outer cortex (intermediate mesoderm) and inner medulla (neural crest ectoderm).
Zona fasciculata produces glucocorticoids (cortisol and cortisone) affecting stress response, metabolism, and immune function.
Zona reticularis synthesizes small amounts of androgens.

Other Hormones and Their Functions

Insulin is released in response to increased plasma glucose and regulates energy use and storage.
Glucagon counters insulin, raising blood glucose levels when they are low.
Enteroendocrine cells produce hormones like gastrin, cholecystokinin, and ghrelin, playing roles in digestive regulation.
Leptin, secreted by adipocytes, signals the hypothalamus to regulate energy balance.

Effects of Glucocorticoids

Glucocorticoids lead to decreased pain sensitivity, increased blood pressure, and elevated blood sugar levels.
They suppress the immune response and can cause digestive issues.

Hormonal Regulation of Blood Pressure

Renin system activated by low blood pressure increases blood volume.
Angiotensin II stimulates cortisol release, promoting gluconeogenesis and reduced glucose usage in muscles and fat.

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Description

Test your knowledge on the parathyroid and thyroid glands, focusing on the roles of parafollicular and chief cells. This quiz covers their activities, hormone secretion, and histological features. Prepare to enhance your understanding of these essential components of the endocrine system.