Ch 10 Endocrine Flashcards
What are hormones?
Chemicals that alter the metabolic activities of many different tissues and organs
Chemical messengers that are released in one tissue and transported by the bloodstream to target cells in other tissues.
Three groups hormones can be divided into based on chemical structure
amino acid derivatives
peptide hormones
lipid derivatives
What are amino acid derivatives
AA derivatives are structurally similar to amino acids, relatively small molecules.
Epi, norepinephrine, thyroid hormones, and melatonin
What are peptide hormones?
Chains of amino acids.
Range from short chain polypeptides such as antidiuretic hormone ADH and oxytocin
To small proteins such as growth hormone and prolactin..
Includes all hormones secreted by the hypothalamus, pituitary gland, heart, kidneys, thymus, digestive tract, and pancreas
Endocrine system
Includes all the endocrine cells and tissues of the body.
Endocrine cells
glandular secretory cells that release their secretions into the extracellular fluid.
Exocrine cells
Secrete onto epithelial surfaces.
Sweat glands
what are lipid derivatives
Two classes of lipid based hormones:
Steroid hormones:lipids that are structurally similar to cholesterol
eicosanoids: fatty acid based compounds derived from the 20 carbon fatty acid arachidonic acid. Affect blood clotting. they include prostaglandin.
What are target cells?
Each hormone has one, they are specific cells that have the receptors that bind and read the hormonal message when it arrives.
What is the first messenger hormone
Hormone that binds to a receptor on the plasma membrane surface.
What is the second messenger hormone?
Intermediary molecule that forms due to hormone-receptor interaction.
Hormones may circulate (blank) or be carried by transport (blank)
freely, Proteins
Free hormones are rapidly removed from the bloodstream.
What is endocrine activity or hormone secretion mainly controlled by
Negative feedback
What does the hypothalamus do?
It regulates the activities of the nervous site and endocrine system in 3 ways
- synthesizes and secretes two hormones into the bloodstream at the posterior lobe of the pituitary gland.
- Secretes regulatory hormones that control the activities of endocrine cells in the anterior lobe of the pituitary gland
- exerts direct neural control over the endocrine cells of the adrenal medullae
Pituitary gland (hypophysis)
Releases 9 important peptide hormones; all bind to membrane receptors, and most use cyclic-AMP as a second messenger
7 come from the anterior lobe and 2 from posterior.
Hypophyseal Portal system
Ensures that all the blood entering the portal vessels will reach target cells in the anterior lobe of the pituitary gland before returning to the general circulation.
7 hormones of the anterior lobe of the pituitary gland
- thyroid stimulating hormone-thyroid hormones
- adrenocorticotropic hormone-steroid hormones
- FSH-sperm production
- LH-ovulation/testosterone
- Prolactin-milk production
- GH-HGH
- Melanocyte-stim. hormone
2 hormones posterior lobe secrete
- ADH released when body is low on water.
2. Oxytocin- promotes labor and delivery, stimulates contractions
What are thyroid follicles and what do they release?
Spheres lined by a simple cuboidal epithelium
T4(thyroxine)
T3(triiodothyronine)
What are C cells and what do they produce?
C cells, or parafollicular cells, are endocrine cells sandwiched between the follicle cells and their basement membrane.
C cells produce the hormone calcitonin. Helps regulate calcium concentrations in body fluids.
Note*
The 4 parathyroid glands, embedded in the posterior surfaces of the thyroid gland, secrete parathyroid hormone to elevate blood calcium levels.
Adrenal glands
superficial to kidneys two parts with separate functions outer adrenal cortex inner adrenal medulla secrete epic and norepi
What does the adrenal cortex manufacture?
more than two dozen Steroid hormones collectively called corticosteroids.
In the blood stream, these hormones are bound to transport proteins.
What are mineralocorticoids?
They affect the electrolyte composition of body fluids.
What is aldosterone?
It is the principal MC (mineralocorticoids) of the adrenal cortex. It stimulates the conservation of sodium ions and the elimination of potassium ions by targeting cells that regulated the ionic composition of excreted fluids.
Specifically it causes the region of sodium by preventing the loss of sodium ions in urine, sweat, and saliva.
adrenal medulla
Produces epinephrine and norepinephrine
Increases cardiac activity, blood glucose levels; release of lipids by adipose tissue
What is the pineal gland?
The pineal gland lies in the posterior portion of the roof of the third ventricle. It contains neurons, glial cells, and secretory cells that synthesize the hormone melatonin.
The pancreas, its location, and its characteristics
Lies in the J shaped loop between the stomach and proximal portion of the small intestine.
It contains both exocrine and endocrine cells
Its primarily a digestive organ whose exocrine cells make the digestive enzymes.
Pancreatic islets
Cells of the endocrine pancreas form clusters called pancreatic islets, containing alpha cells and beta cells. Alpha cells produce glucagon, and beta produce insulin.
what is calcitriol?
Secreted by the kidneys
Stimulates the absorption of calcium and phosphate ions across the intestinal lining of the digestive tract.
What is erythropoietin (EPO)
released by the kidneys in response to low oxygen levels in kidney tissues.
EPO stimulates the red bone marrow to produce red blood cells.
What is renin
Released by specialized kidney cells
In response to decline in blood volume, blood pressure, or both.
Renin activity leads to a formation of angiotensin II (vasoconstrictor) which is the hormone that stimulated the production of aldosterone in the adrenal cortex.
The heart endocrine response
The endocrine cells in the heart are cardiac muscle cells in the walls of the right atrium; this chamber receives blood from the largest veins.
if blood volume becomes to great, these cardiac muscle cells are stretched, stimulating them to release the hormone atrial natriuretic peptide (ANP) which promotes the loss of sodium ions and water by the kidneys.
the thymus
Produces several hormones called thymosins which play a role in developing and maintaining normal immune defenses.
The testes
The interstitial cells of the testes produce the steroid hormones know as androgens. Testosterone is the most important androgen.
Events that could happen if hormones interact with each other
- antagonistic (opposite0
- synergistic (additive)
- permissive
- integrative
