Endocrine System Pre-lab Flashcards

Questions and Answers

What is an endocrine organ (gland)?

A gland that is only active during childhood

A gland that produces digestive enzymes

A ductless gland that regulates body functions (correct)

A gland that secretes hormones into ducts

Define a hormone.

Chemical messengers secreted into the bloodstream by endocrine glands that initiate a change in a target cell.

What are target tissues?

Tissue that contains the cells with receptors for a particular hormone.

What is negative feedback?

A mechanism in which a deviation in a physiological variable triggers a response that restores the variable to its set point. Signup and view all the answers

What is the function of the hypothalamus?

Releases hormones that stimulate or inhibit the anterior pituitary and stores ADH and oxytocin in the posterior pituitary. Signup and view all the answers

What hormones does the anterior pituitary secrete?

Hormones that largely affect other glands. Signup and view all the answers

What hormones are stored in the posterior pituitary?

ADH and oxytocin. Signup and view all the answers

Where is the thyroid gland located?

In the anteroinferior neck. Signup and view all the answers

What do parathyroid glands secrete?

Parathyroid hormones that maintain calcium ion homeostasis. Signup and view all the answers

What does the pineal gland secrete?

Melatonin. Signup and view all the answers

What is the primary function of the thymus gland?

To secrete thymosin and thymopoietin. Signup and view all the answers

What does the pancreas produce?

Insulin and glucagon. Signup and view all the answers

What is the adrenal cortex responsible for?

Secreting steroid hormones. Signup and view all the answers

Which hormones does the adrenal medulla secrete?

Epinephrine and norepinephrine. Signup and view all the answers

Which of the following hormones are antagonists?

Insulin and glucagon Signup and view all the answers

The posterior pituitary produces no hormones of its own.

True Signup and view all the answers

Insulin triggers actions that _____ the concentration of glucose in the blood.

lower Signup and view all the answers

Interstitial cells within the testes produce __________.

testosterone Signup and view all the answers

_______ is the adrenal hormone responsible for the stress response.

Cortisol Signup and view all the answers

Parathyroid hormone triggers actions that ______ the concentration of calcium ions in the blood.

raise Signup and view all the answers

The hypothalamus communicates with the ________________________ via the hypothalamic-hypophyseal portal system.

Anterior pituitary gland Signup and view all the answers

Which of the following is true regarding endocrine organ histology?

The adrenal cortex has three zones of cells that secrete steroid hormones. Signup and view all the answers

In a negative feedback loop, you would expect secretion from an endocrine gland to ______________ after homeostasis has been restored.

decrease Signup and view all the answers

How does the hypothalamus communicate with the anterior and posterior pituitary glands?

The hypothalamus secretes releasing and inhibiting hormones into capillaries for the anterior pituitary, while axon terminals in the posterior pituitary store hormones. Signup and view all the answers

What are the effects of excess parathyroid hormone secretion?

Hypercalcemia and weakened bones, leading to bone fractures. Signup and view all the answers

What symptoms would be observed from a pheochromocytoma?

Elevated heart rate and blood pressure due to excessive sympathetic nervous system stimulation. Signup and view all the answers

How does diabetes mellitus affect blood glucose levels?

It increases the level of glucose in the blood, causing hyperglycemia. Signup and view all the answers

What effect does a glucagonoma have on blood glucose levels?

It increases blood glucose levels through excess glucagon secretion, leading to hyperglycemia. Signup and view all the answers

How does hyperthyroidism affect TSH levels?

It leads to a low level of TSH due to feedback inhibition. Signup and view all the answers

What symptoms arise from excess ADH secretion?

Abnormal water retention from the kidneys, leading to overhydration. Signup and view all the answers

Study Notes

Endocrine System Overview

Endocrine organs are ductless glands that maintain homeostasis through hormone secretion into the bloodstream.
Hormones act as chemical messengers, initiating changes in target cells containing specific receptors.

Key Components

Hypothalamus: Connects endocrine and nervous systems; regulates the anterior pituitary and synthesizes ADH and oxytocin.
Pituitary Gland:
- Anterior Pituitary: Secretes hormones that regulate other glands, significantly influenced by hypothalamic hormones.
- Posterior Pituitary: Stores and releases hormones (ADH and oxytocin) produced in the hypothalamus.
Thyroid Gland: Produces thyroid hormones (T3, T4) and calcitonin, crucial for metabolism and calcium homeostasis.
Parathyroid Glands: Release parathyroid hormone for calcium regulation in the blood.

Other Endocrine Glands

Pineal Gland: Produces melatonin in response to light, regulating circadian rhythms.
Thymus Gland: Produces thymosin, especially active in childhood, relevant for immune function.
Pancreas: Functions as both an endocrine (insulin and glucagon) and exocrine gland (digestive enzymes).
Adrenal Gland:
- Cortex: Produces steroid hormones (aldosterone, cortisol) involved in metabolism and stress response.
- Medulla: Releases epinephrine and norepinephrine, mediating fight-or-flight responses.
Ovaries & Testes: Responsible for producing sex hormones (estrogens, progesterone, testosterone) affecting reproduction.

Mechanisms of Hormonal Regulation

Negative Feedback: Restores physiological variables to set points; response diminishes once balance is achieved.
Hormonal interactions often involve antagonist pairs, like insulin and glucagon, which have opposing effects on blood glucose levels.

Pathologies & Hormonal Dysregulation

Diabetes Mellitus: Results from insufficient insulin or target cell insensitivity, raising blood glucose levels.
Hyperthyroidism: Characterized by high T3 and T4 levels leading to low TSH due to negative feedback failure.
Tumors:
- Pheochromocytoma: Causes excess catecholamines, resulting in elevated heart rate and blood pressure.
- Glucagonoma: Leads to excess glucagon secretion causing hyperglycemia, similar to diabetes.

Clinical Symptoms and Effects

Excess parathyroid hormone causes hypercalcemia, weakening bones.
Inappropriate ADH secretion results in water retention and dilutional hyponatremia (overhydration symptoms).

By understanding these key facts and mechanisms, one gains a clearer picture of the endocrine system's operations, its components, and the implications of its dysfunctions.

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Description

This quiz features flashcards on key concepts related to the endocrine system, including definitions of endocrine organs, hormones, and target tissues. It's a helpful resource for students preparing for labs or reviewing essential terminology surrounding endocrine functions.