Endocrine System BIOL244 Exam 1

What is the structure of adrenal glands?

the adrenal medulla and adrenal cortex make up one adrenal gland

What are the layers of the adrenal cortex?

Zona glomerulosa, Zona fasciculata, and Zona reticularis

What does the zona glomerulosa produce?

mineralocorticoids (hormones that help control the balance of minerals and water in the blood)

What does the zona fasciculata produce?

glucocorticoids (these play a role in stress response)

What does the zona reticularis produce?

gonadocorticoids (adrenal sex hormones)

The ________ produces over 24 steroid hormones called corticosteroids that are derived from cholesterol.

adrenal cortex

What corticosteroid matches this description:

the main function is the regulation of electrolyte concentrations in extracellular fluids; primary one is Aldosterone

mineralocorticoid

What corticosteroid matches this description:

ex (cortisol, corticosterone, and cortisone), keep blood glucose levels fairly constant, maintain blood pressure by affecting the diameter of blood vessels

glucocorticoids

What corticosteroid matches this description:

mostly weak androgens that are converted to estrogen and testosterone

gonadocorticoids

What activates the release of mineralocorticoids?

decreasing blood volume or pressure

elevated blood potassium levels

ACTH

What inhibits the release of mineralocorticoids?

increased blood volume or pressure

decreased blood potassium levels

What is the target organ of mineralocorticoids?

kidneys

What are the major effects of mineralocorticoids?

aldosteronism (hypersecretion) and addison’s disease (hyposecretion), increase blood levels of sodium and decrease blood levels of potassium (causing blood volume and pressure to rise)

What is the target organ for glucocorticoids?

body cells

What are the major effects of glucocorticoids?

Cushing’s syndrome (hypersecretion), Addison’s disease (hyposecretion)

What are the major effects for gonadocorticoids?

virilization of females (adrenogenital syndrome) (hypersecretion)

What type of stimuli is being described:

changing blood levels of certain critical ions and nutrients

humoral

What type of stimuli is being described:

occur when nerve fibers stimulate hormone release

neural

What type of stimuli is being described:

hormones from other endocrine glands that cause hormone release

hormonal

This is an example of what stimuli:

Neural, Hormonal, Humoral?

capillary blood contains low concentration of calcium which stimulates secretion of parathyroid glands

humoral

This is an example of what stimuli:

Neural, Hormonal, Humoral?

preganglionic sympathetic fibers stimulate adrenal medulla cells to secrete catecholamines (epinephrine and norepinephrine)

neural

This is an example of what stimuli:

Neural, Hormonal, Humoral?

the hypothalamus secretes hormones that stimulate other endocrine glands to secrete hormones

hormonal

These glands produce hormones and lack ducts; they release hormones via diffusion into surrounding tissue fluids (such as blood and lymph.

endocrine glands

The anterior pituitary, thyroid, parathyroid, adrenal, and pineal glands are what type of gland?

endocrine gland

It has neural functions and also produces and releases hormones, so it is considered a …

neuroendocrine organ

The hypothalamus is considered a …..

neuroendocrine organ

What organs contain endocrine tissue?

pancreas, gonads (ovaries and testes), and placenta

What organs and tissues contain endocrine cells?

adipose cells, and the thymus, small intestine, stomach, kidneys, and heart

What kind of gonads are located in the abdominopelvic cavity?

ovaries

What kind of gonads produce eggs and female sex hormone?

ovaries

What hormones do the ovaries produce?

estrogen and progestrone

What hormones does the placenta produce?

estrogen, progesterone, and human chorionic gonadotropin (hCG)

_______ are chemicals with local effects that exert their effects on the same cells that secrete them.

autocrine

________ also act locally but they affect cell types other than those releasing them.

paracrine

________ are long-distance chemical signals secreted by cells into extracellular fluids, and they regulate the metabolic function of other cells in the body.

hormones

How do hormones affect target cells?

1) alter plasma membrane permeability or potential

2) stimulating synthesis of proteins or regulatory molecules such as enzymes within the cell

3) activating or deactivating enzymes

4) inducing secretory activity or stimulating mitosis

What is the role of the posterior pituitary gland with respect to the hypothalamic hormones?

the posterior pituitary stores and releases the hypothalamic hormones

______ glands produce non-hormonal substances and have ducts that carry them to a membrane surface.

exocrine

_____ glands produce hormonal substances and lack ducts and release hormones via **diffusion** into blood and lymph.

endocrine

What organ produces atrial natriuretic peptide (ANP)?

the heart

What is the function of atrial natriuretic peptide?

stimulates the kidneys to increase their production of urine; reduces blood volume and blood pressure (this decreases Na in extracellular fluid)

Within the __________ , there are enteroendocrine cells in mucosa that release hormones that regulate digestion

gastrointestinal tract

What are the enteroendocrine cells?

gastrin, secretin, cholecystokinin (CCK), and incretins

What is the function of gastrin?

stimulates the release of hydrochloric acid in the stomach

What is the function of secretin?

stimulates the release of digestive substances by the liver and pancreas in response to food (but inhibits secretory activity in the stomach)

What is the function of cholecystokinin?

stimulates digestive activity

What is the function of Incretins?

enhance insulin release and inhibit glucagon release

What hormones do the kidneys secrete?

erythropoietin and renin

What is the function of erythropoietin?

signals bone marrow to increase its production of red blood cells

What is the function of renin?

initiates the renin-angiotensin mechanism of aldosterone release

What hormone does skin produce?

cholecalciferol

What is the function of cholecalciferol?

stimulates active transport of dietary calcium across intestinal cell membranes

What hormone do adipose cells produce?

leptin

What is the function of leptin?

tells your body how much stored energy (fat) you have, and suppresses appetite and increases energy expenditure

In the skeleton what hormone do osteoblasts secrete?

osteocalcin

What is the function of osteocalcin?

stimulates pancreatic beta cells to divide and secrete more insulin

What peptide hormones does the thymus produce?

thymulin, thymopoietins, and thymosins

What is the function of thymulin, thymopoietins, and thymosins?

involved in the development of T lymphocytes and the immune response

What do acinar cells produce?

an enzyme-rich juice that is carried by ducts to the small intestine where it aids in digestion

What are the cells in the pancreatic islets?

alpha and beta cells

What do alpha cells produce?

glucagon

What do beta cells produce?

insulin

What is the function of glucagon?

promotes the breakdown of glycogen to glucose (glycogenolysis), gluconeogenesis, and promotes the release of glucose to the blood by liver cells (the liver makes glucose available to other tissues in the body)

What is gluconeogenesis?

synthesis of glucose from lactic acid and non-carbohydrate molecules in the liver

What is the target organ of glucagon?

the liver

What is glycogenesis?

the formation of glycogen from sugar

If blood glucose levels drop too low, the pancreas is stimulated to release ______.

glucagon

If blood glucose levels rise, the pancreas is stimulated to release ______.

insulin

What is the function of insulin?

lowers blood glucose levels, inhibits glycogenolysis and gluconeogenesis, stimulates glycogenesis

What is the target organ for insulin?

the liver

The parathyroid glands contain ____ cells and ____ cells. The chief cells secrete **parathyroid hormone** (PTH)

chief and oxyphil

What do chief cells secrete?

parathyroid hormone

What are the target organs for parathyroid hormone?

skeleton, kidneys, and intestine

What determines the release of parathyroid hormone?

falling blood calcium levels

What is the function/effect of parathyroid hormone?

controls the calcium balance of blood

How does PTH stimulate the skeleton?

stimulates osteoclasts, which release enzymes that dissolve bone matrix and thus leads to the release of calcium and phosphates to blood

How does PTH stimulate the kidneys?

enhances reabsorption of calcium

How does PTH stimulate the intestines?

promotes the activation of vitamin D (which is required for absorption of calcium from food)

Where is the pineal gland located?

hangs from the roof of the third ventricle in the diencephalon

What is the role of melatonin?

plays a role in sleep, stimulated by night time

What are the anterior pituitary hormones?

growth hormone (GH)

prolactin (PRL)

thyroid-stimulating hormone (TSH)

adrenocorticotropic hormone (ACTH)

follicle-stimulating hormone (FSH)

luteinizing hormone (LH)

What is the target organ and function of TSH?

* thyroid
* stimulates the normal development and secretory activity of 2 the thyroid gland

What is the target organ and function of ACTH?

* adrenal cortex
* stimulate the adrenal cortex to release corticosteroid hormones (glucocorticoids) that help the body resist stressors

What determines the release of TSH?

when stimulated by thyrotropin-releasing hormone

What determines the release of ACTH?

stimulated by corticotropin-releasing hormone (CRH)

What is the target organ and function of FSH?

* ovaries and testes
* stimulates gamete production

What determines the release of FSH and LH?

gonadotropin-releasing hormone (GnRH)

What is the target organ and function of LH?

* ovaries and testes
* promotes the production of gonadal hormones (testosterone, estrogen, progesterone)

What determines the release of GH?

growth hormone releasing hormone (GHRH) and growth hormone inhibiting hormone (GHIH, somatostatin)

What are the target organs and functions of GH?

* bones and skeletal muscles
* stimulates most body cells to increase in size and divide

What determines the release of prolactin (PRL)?

primarily the prolactin inhibiting hormone (PIH, dopamine)

What is the target organ and function of prolactin?

* mammary glands
* stimulates milk production in the breasts

Why do all of the amino-acid based hormones (except thyroid hormone) use **intracellular second messengers**?

the water-soluble hormones can’t cross the plasma membranes of cells

What is the general process of intracellular second messengers?

* hormones exert their effects on target cells via intracellular second messengers
* (these are activated when the hormones binds to receptors associated with the target cell membrane)
* G proteins couple the second messenger and hormone receptor

What are the steps for the cyclic AMP signaling mechanism?

1. First, the hormone binds to a receptor on the target cell plasma membrane (changing the shape of the receptor, activating a G protein)
2. The activated G protein stimulates adenylate cyclase. AC generates a second messenger called cyclic AMP (cAMP) from ATP
3. Cyclic AMP triggers a cascade of chemical reactions by activating protein kinases
4. Enzymes in the target cell are either activated or inactivated

What are amino acid based hormones made from?

peptides or complex proteins

What are steroid hormones made from?

cholesterol

Where is the thyroid gland located?

in the anterior neck, on the trachea

What cells can be found in the **follicles** of the thyroid gland and what do they produce?

follicle cells, thyrogloblin

colloid, produces thyroid hormone

parafollicular cells, calcitonin

What is the target organ and function of the thyroid hormone?

* all body cells
* regulate metabolism, body heat production, and regulating tissue growth and development