Week 4 endocrine system Flashcards
What are the master endocrine glands?
hypothalamus and pituitary glands(Anterior/Posterior)
How is the hypothalamus connected to the anterior pituitary?
blood vessels
How is the hypothalamus connected to the posterior pituitary?
Infundibulum / Stak, (special tissue that runs from hypothalamus to posterior pituitary
What are the specialized cells called that run from the hypothalamus to the posterior pituitary?
neuroendocrine cells
The dendrites and cell body of the neuroendocrine cells are found in the _________.
hypothalamus
The axon body of the the neuroendocrine cells are found in the __________.
infundibulum
The axon terminal of the neuroendocrine cells are found in the _______ _______.
posterior pituitary
Neuroendocrine cells release ______ rather than ________.
hormones , neurotransmitters
Neuroendocrine cells look like ____ but function as ____ cells.
neurons, endocrine
What are the two different types of neuroendocrine cells ?
Supraoptic and paraventricular
Supraoptic produces and secretes:
ADH
Paraventricular cell produces and secretes:
Oxytocin
ADH and Oxytocin are _______ in the hypothalamus and are _____ /_____ by the posterior pituitary.
produced, stored/secreted
ADH stands for
anti-diuretic hormone
ADH prevents you from _______ and causes you to _____ water.
urinating, retain
Wha are the signals for ADH release?
Dehydration: increased solute(NOT WATER) concentration (osmolarity) & decreased BP
Describe the release of ADH
ADH produced in hypothalamus->stored/released by post.pituitary-> ADH travels to kidney collecting ducts-> enters water channels and causes reobsorption
What causes oxytocin to be released?
cervical/uterine contraction and breast sucking
What happens when oxytocin reaches the uterus?
the myometrium contracts causing labor
What does oxytocin do after labor?
causes the cervix/uterus to revert back to its normal shape
What happens when oxytocin reaches the breast?
milk ejection
Growth hormones are produced by _________.
Somatotrophs
Somatotrophs are located in the
anterior pituitary
what causes growth hormone to be released ?
GhRH (growth hormone releasing hormone)
In childhood/adolescence the growth hormone causes an increase in _____&_____ by releasing ______ _____ _____ _______ from the _____.
mass & length, insulin like growth factors (IGFs), liver
In adults the growth hormone causes :
gluconeogenesis: glycogen and fats to be converted into glucose
The zona glomerulosa layer of the adrenal cortex releases
ALDOSTERONE (mineralocorticoid)
The zona fasciculata layer of the adrenal cortex releases
CORTISOL (Glucocorticoid / Corticosterone)
The zona reticular layer of the adrenal cortex releases
SEX HORMONES
Androgens
The adrenal medulla layer of AC (adrenal cortex) releases
EPINEPHRINE &
NOREPINEPHRINE
(Catecholamines)
Epinephrine & norephinephrine activate the
sympathetic nervous system (fight/flight)
What causes CRH (Corticotrophin releasing hormone) to be released?
Morning peaks, fever, and hypoglycemia
What causes anterior pituitary to release ACTH
CRH (Corticotrophin releasing hormone)
What cells cause ACTH to release its hormones
Corticotrophs
What does ACTH cause the adrenal gland to release?
cortisol, sex hormones, and aldosterone
What does cortisol do?
controls sacadian rhythm (sleep wake cycle), maintains BS lvls (fat/protein/carbohydrate metabolism), suppresses immune system, anti-inflammatory actions, maintains BP/blood vessel tone/proper cardiac contraction, CNS activation
What are the sex hormones that are released also known as ?
weak androgens
What are the three sex hormones(weak androgens) that are released?
Androstenedione & Dehydroepiandrosterone (DHEA) -> (T & E) , &
Estradiol
When Dehydroepiandrosterone (DHEA) reaches the gonads it turns into either
estrogen or testosterone
Weak androgens are presents during:
puberty, sex drive, and after menopause (estradiol)
Renin-angiotensin aldosterone-system (RAAS) is a
complex multi organ endocrine (hormone) system involved in the regulation of blood pressure.
Angiotensinogen is produced by the _____ and is secreted in the ______ in its ______ form.
liver, plasma, inactive
In the RAAS, low blood pressure is detected by
baroreceptors
The baroreceptors are found within the
afferent arteriole
The afferent arterioles are found within the
kidneys
What are the steps of RAAS:
- Drop in BP is detected by baroreceptors in afferent arterioles which causes renin to be released into plasma 2. in the plasma, renin finds the angiotensinogen which is in its inactive form and converts it to angiotensin I 3. Angiotensin I then travels to the lungs where the angiotensin converting enzyme is waiting for it and converts it to angiotensin II 4. Angiotensin II then travels to the adrenal cortex causing it to release the hormone aldosterone (when traveling to cortex it causes vasoconstriction of blood vessels which causes increased BP) 5. Aldosterone then travels to the collecting duct in the kidneys causing sodium to be re-absorbed and potassium to be secreted (salt retention)thus causing BP to rise again
What causes hypothalamus to release TRH?
low T3 & T4
What hormone causes the anterior pituitary gland to release TSH?
TRH (thyrotropin releasing hormone)
What gland houses TSH?
anterior pituitary gland
What gland houses T3/T4?
Thyroid
What causes the thyroid gland to release T4/T3?
TSH
Where do T3/T4 go when released from thyroid gland?
to peripheral tissues
A majority of T3/T4 that is released is
T4
Which hormone cannot be utilized by the peripheral tissues ? T3 or T4
T4
When T4 reaches the peripheral tissues it is converted into ____ via an enzyme called _____.
T3, iodinase
What does t3/t4 do in the body?
involved in heart rate, digestion, brain function, hair/skin, bones, muscles, and metabolism
Exocrine part of pancreas affects
digestion
What is the endocrine portion of pancreas called
islets of langerhans
what are the three cells of the endocrine part of the pancreas
alpha , beta , delta
Alpha cells secrete
glucagon
What is the function of glucagon
to increase blood glucose
Beta cells secrete
insulin
what is the function of insulin
to decrease blood sugar
Delta cells secrete
somatostatin
What is the function of somatostatin
inhibits alpha and beta from releasing glucagon/insulin
How does the beta cell release insulin
high glucose levels in plasma->glucose goes into the cell->glucose converts to ATP-> ATP causes ATP sensitive K+ channel to close-> cell depolarizes-> causes voltage Ca2+ channels to open-> Ca2+ enters causing exocytosis of insulin
What two glands aid in the calcium balance:
thyroid gland and parathyroid gland
What are the two hormones that the thyroid gland produces
calcitonin and T3/T4
What is t3/t4 responsible for
metabolism
What is calcitonin responsible for ?
to decrease Ca levels
What is the hormone produced by the parathyroid gland?
PTH(parathyroid hormone)
What is the function of the parathyroid hormone?
Increase calcium levels
Calcium balance process
- Calcium lvl rises above set point 2. thyroid gland releases calcitonin 3. Blood calcium lvl falls 4. If calcium lvl falls below set point 5. Parathyroid glands release PTH 6. blood calcium lvl rises
PTH (parathyroid hormone) works on which organs and structures
kidneys, bones, and intestines
Calcitonin works on which organs and structures
kidneys & bones
In the bone, calcitonin causes
activates osteoblast activity which builds bone by taking calcium from blood and putting into bone, (increases bone calcium by decreasing blood calcium)
In the kidneys, calcitonin causes
increased calcium secretion in the urine
How does calcitonin cause calcium lvls to go down
by producing bone and by secreting the calcium through urine
In the bone, PTH causes
activates osteoclast activity which breaks bone down and thereby transferring calcium from the bone into the blood
In the kidneys, PTH causes
your kidneys to reabsorb calcium through urine, it also activates Vitamin D which causes calcium to be absorbed through the intestines from your diet
How does PTH cause your blood calcium lvls to increase?
by breaking bone down, causing your kidneys to reabsorb calcium through urine, and by causing your intestines to absorb calcium through intestines via vitamin D