EXAM 5: The Endocrine System Flashcards
Which has quicker and more precise communication, endocrine or nervous system?
Nervous, endocrine is slower and more widespread.
What gland has both endocrine and exocrine functions? What system is this important to?
Pancreas; Digestive
What glands are among the key sites for hormone production and release?
Endocrine
What glands secrete their products into ducts?
Exocrine
Where does the endocrine system secrete hormones?
Into the interstitial fluid that surrounds each cell, then they diffuse into the blood stream
What are the two classes of hormones?
Lipid soluble and Water soluble
Describe Lipid soluble (hydrophobic) Hormones
Can’t freely move through bloodstream, needs a chaperone
Target cell: can DIFFUSE into target cell
steroid
Describe water soluble hormones
Can dissolve in blood on their own
Target cell: Needs transport protein
Amino acid hormone
What is the “Golden Rule of Hormones”?
Any cell with a receptor for the hormone will be sensitive to that hormone.
Why will the number of hormone receptors on the cell membrane’s surface change?
Depending on need
What happens in Down-Regulation?
- Number of receptors decreases
- Makes the target tissues LESS sensitive
When does Down-Regulation occur?
When there are TOO MANY hormones in the blood stream
When does Up-Regulation occur?
When there is NOT ENOUGH hormones in the bloodstream
What happens in Up-Regulation?
-Number of receptors increase
- Makes the target tissue more sensitive
What are some responses that can occur when a hormone binds to a receptor on its target cell:
Increase or decrease in gene expression
Increase or decrease in metabolism
Increase or decrease in secretion
What gland sits on top of the kidney?
Adrenal (Suprarenal) glands
What does the adrenal medulla contain?
the inner core of gland tissue, which is 10-20% of the total gland volume
Two main functions of the inner core of adrenal?
1.) Endocrine Gland
2.) Sympathetic Nervous System Ganglion
What do chromaffin cells release when stimulated?
Catecholamines
What are 4 effects of catecholamines?
- Increased heart rate
- Dilated blood vessels
- Increased blood pressure
- Increased breathing rate
What is another name for epinephrine?
Adrenaline
What is the adrenal cortex?
The cortex that surrounds the medulla and secretes several hormones from three layers of glandular tissue.
Name the 3 zones of the adrenal cortex
1.) Zona Glomerulosa
2.) Zona Fasciculata
3.) Zona Reticularis
What hormone is secreted in the Zona Glomerulosa?
Aldosterone
What hormone is secreted in the Zona Fasciculata?
Cortisol
What hormone is secreted in the Zona Reticularis?
Androgens
What is cortisol?
The stress hormone
Cortisol is secreted in response to the release of what hormone?
ACTH
What are the metabolic effects of cortisol?
Repair of tissues
Aldosterone is secreted as a response to what?
Hormonal signals from the kidneys
What is the purpose of aldosterone?
Helps retain water
Causes the retention of Na+
What is the largest gland that is all the way endocrine?
Thyroid Gland
Name the hormones secreted by the thyroid gland:
- Thyroxine
- Triiodothyronine
- Calcitonin
How many iodine atoms does thyroxine have?
4
How many iodine atoms does triiodothyronine have?
3
What hormone do the parathyroid glands secrete?
Parathyroid hormone (PTH)
What are the two ways that PTH works to raise blood Ca2+?
Calcitriol Synthesis
Bone resorption
What is Calcitriol synthesis?
Increased absorption of Calcium from food
What does bone resorption do?
Increase osteoclasts
What is the largest gland in the body?
Endocrine Pancreas
What does endocrine pancreas do?
Blood Glucose Regulation
What does exocrine pancreas do?
Digestive Enzyme Production
What do Beta cells secrete?
Insulin
What do Delta cells secrete?
Somatostatin
What do Alpha cells secrete?
Glucagon
What causes insulin to be secreted by beta cells?
Increased blood glucose levels
What does insulin stimulate cells to do?
Use or store glucose
What is insulins job?
LOWER blood glucose levels after a meal
What are the 3 ways that insulin lowers our blood glucose levels?
- Metabolizing glucose to create ATP (Glycolysis)
- Converting the excess into fat (Adipose)
- Traffic to liver or muscle to create glycogen (glycogenesis)
What disease is associated with an insufficiency of insulin production?
Type 1 Diabetes
What disease is associated with an insufficiency of insulin reaction?
Type 2 Diabetes
Name the steps used as insulin works in the body:
1.) You eat a meal
2.) Insulin is released from beta cells in pancreas
3.) Insulin binds to insulin receptor
4.) Opens glucose/Na+ symporter
5.) Sodium carries glucose into cell
What step is inflicted by Type 1 Diabetes?
Release of insulin from beta cells in pancreas
What step is inflicted by Type 2 Diabetes?
Insulin binding to insulin receptors
Glucagon is released by alpha cells in response to what?
LOW blood glucose levels
What does glucagon stimulate cells to do?
Recycle or produce glucose
What is the job of glucagon?
RASIE our blood glucose levels during fasting
What are the 3 ways that glucagon raises blood glucose levels?
- Increase production of glucose (New glucose- Gluconeogenesis)
- Break apart glycogen (glycogenolysis)
- Increase release of stored glucose
What does glucagon turn to when it raises blood glucose levels during fasting?
Fats, lipids, and proteins
Where is the pituitary gland suspended from?
The floor of the hypothalamus by a stalk called the infundibulum/hypophysis and is housed on a bony depression called the sella turcica.
What are the two structures of the pituitary?
Anterior and Posterior
What does the anterior pituitary use to communicate with the hypothalamus?
Hypophyseal Portal System
What does the posterior pituitary use to communicate?
Axons (nerve fibers)
The anterior pituitary gland (adenohypophysis) arises from what?
Primordial Pharynx, ,making it epithelial tissue
The posterior pituitary gland (neurohypophysis) is what kind of tissue?
Nervous
Anterior Pituitary Embryonic Origin?
Oral Epithelial
Posterior Pituitary Embryonic Origin?
Nervous tissue
Adrenocorticotropic Hormone (ACTH) targets what?
Adrenal gland
ACTH releases what?
CRH
Human Growth Hormone (hGH) targets what?
Liver and muscles
hGH releases what?
GHRH, GHIH
Thyroid-stimulating hormone (TSH) releases what?
TRH
Follicle-stimulating hormone (FSH) and Luteinizing Hormone (LH) release what?
GnRH
Prolactin (PRL) targets and does what?
Breast Milk Production
PRL releases what?
PRH and PIH
How does the hypothalamus control its release of hormones?
Tells anterior pituitary to release SPECIFIC hormones
How does the hypothalamus control its inhibition of hormones?
Tells anterior pituitary NOT to release specific hormones
What kind of feedback does the hypothalamus use to closely control the secretion of anterior pituitary hormones?
Negative feedback from target glands
What does HPO axis stand for?
H- Hypothalamus
P- Anterior Pituitary
O- Organ ( thyroid, adrenal gland, gonads)
The secretion of ACTH is controlled by what?
Corticotropin releasing hormone (CRH)
The secretion of hGH is stimulated by what?
Growth Hormone Releasing Hormone (GHRH)
Growth Hormone Inhibiting Hormone (GHIH)
What does hGH signal the liver to secrete?
Insulin-like Growth Factor 1 (IGF-1) which promotes cell division
The secretion of Thyroid Stimulating Hormone (TSH) is stimulated by what?
Thyrotropin- releasing hormone (TRH)
TSH signal the thyroid gland to secrete what?
Triiodothyronine (T3) and Thyroxin (T4)
TSH and TRH are inhibited by rising levels of what?
T3 and T4
Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) are stimulated by what and act on what?
Gonadotropin Releasing Hormone (GnRH), act on gonads
Prolactin release is stimulated by what?
Prolactin releasing hormone (PRH) and Prolactin Inhibiting Hormone (PIH)
PRL is LOW unless what?
A mother is breastfeeding
Nuclei of Antidiuretic Hormone (ADH)?
Supraoptic Nucleus
Nuclei of Oxytocin (OT)?
Paraventricular Nucleus
What is the bonding hormone?
Oxytocin
What is the ONLY positive feedback hormone?
Oxytocin
Oxytocin does what?
- Enhances smooth muscle contractions and facilitates labor and delivery
- Stimulates milk ejection from the mammary glands after delivery
Antidiuretic hormone (ADH) does what?
Increase blood pressure by minimizing the amount of water excreted in the kidneys.