Endocrine System Flashcards
Prolactin
From anterior pituitary, stimulates milk production and secretion
GH
From anterior pituitary, stimulates bone and muscle growth
ACTH
From anterior pituitary, stimulates the adrenal cortex to synthesize and secrete glucocorticoids
TSH
From anterior pituitary, stimulates the thyroid to produce thyroid hormones
LH
From anterior pituitary, stimulates ovulation in females and testosterone synthesis in males
FSH
From anterior pituitary, stimulates follicle maturation in females and spermatogenesis in males
Oxytocin
Synthesized in hypothalamus, secreted by posterior pituitary. Stimulates uterine contractions during labor and milk secretion during lactation
ADH vasopressin
Synthesized in hypothalamus and stored in posterior pituitary, stimulates ware absorption in the kidneys
Thyroid hormone
From thyroid, stimulates metabolic activity
Calcitonin
From thyroid, decreases the blood calcium level
Parathyroid hormone
From parathyroid, increases the blood calcium levels
Glucocorticoids
From adrenal cortex, increases blood glucose level and decrease protein synthesis
Mineralcorticoids
From adrenal cortex, increase water absorption in the kidneys
Epinephrine and norepinephrine
Adrenal medulla, increas blood glucose level and heart rate
Glucagon
Pancreas, stimulates conversion of glycogen to glucose in the liver, increases blood glucose
Insulin
Pancreas, stimulates conversion of glycogen to glucose in the liver, increases blood glucose
Somatostatin
Pancreas, suppresses secretion of glucagon and insulin
Testosterone
Testis, maintains male secondary sex characteristics
Progesterone
Ovary/placenta, promotes growth and maintenance of endometrium
Estrogen
Ovary placenta , maintains female secondary sex charactaristics
Melatonin
Pineal, unclear in humans
Erythropoietin
Kidney, stimulates bone marrow to increase production of erythrocytes.
Atrial natriuretic hormone
Heart, involved in osmoregulation
Thymosin
Thymus, stimulates T lymphocytes development
Autocrine
A cell stimulates itself
Endocrine glands in the brain
Pineal body, hypothalamus, pituitary gland.
Endocrine glands in the body
Parathyroid, thyroid, adrenal, pancreas, and ovaries
Hypothalamus controls the ____
Pituitary
Hypothalamic control pituitary is via ____ signaling
Paracrine hormones into the hypophyseal portal system (hypophysis is a name for the pituitary)
Posterior pituitary releases
Oxytocin, ADH
Anterior pituitary releases
GH, ACTH, TSH, FSH, LH, and prolactin
Pathway of releasing glucocorticoids
- Hypothalamus releases CRH
- Flows to anterior pituitary
- ACTH is released
- ACTH stimulates adrenal glands to secrete glucocorticoids
- In extreme situations the hypothalamus also secretes vasopressin to further activate adrenals.
- Negative feedback mechanism
Mnemonic to remember seven hormones of the anterior pituitary
FLAT PEG FSH LH ACTH TSH PROLACTIN ENDORPHINS GH
GnRH from hypothalamus releases ____ from anterior pituitary
FSH and LH
When the hypothalamus secretes PIF (prolactin inhibitory factor)
The anterior pituitary does not release prolactin
CRF from the hypothalamus
Stimulates ACTH from the anterior pituitary
Tumor in the pituitary often causes
Compression of the portal system from hypothalamus. Excessive prolactin
The hypothalamus is connected to the posterior pituitary via
Nerves
Hormones from the anterior pituitary that are trophic proteins and act by
Binding to the membrane and starting a cascade of secondary messengers
Excess of GH causes _____. Lack of GH causes _____.
Gigantism, dwarfism
Adults with excess GH have
Increased growth in small bones without epiphyseal plates
Direct hormones from anterior pituitary
GH, prolactin and endorphins
Lack of iodine results in improper ability for the ____ to function
Thyroid
Increased amounts of T3 and T4 will result in
Increased levels of cellular respiration
Hyper means ____
Hypo means _____
More
Less
Four important functions of calcium
- Principal component of bone
- Regulator of muscle contraction
- Cofactor for normal blood clotting
- Neurotransmitter release
The thyroid produces what hormones
T3, T4, and calcitonin
Calcitonin decreases blood calcium levels in three ways:
- Increased excretion from kidneys
- Decreased absorption from the gut
- Increased storage in the bone
Two hormones that are antagonistic in terms of calcium levels
Calcitonin and PTH
Adrenals are located
On top of the kidneys
Adrenal cortex releases
Corticosteroids ( glucocorticoids, mineralcorticoids, and cortical sex hormones) after stimulation by ACTH from anterior pituitary after stimulation from CRF from hypothalamus
Name two glucocorticoids
Cortisol and cortisone
Cortisol and cortisone increase
Increase gluconeogenesis and decrease protein synthesis. Also decrease inflammation and immunological responses
Example of a mineralcorticoid
Aldosterone
Pathway of aldosterone release
Decreased blood volume causes kidney to release renin which activates angiotensin which stimates adrenal cortex to secrete aldosterone
Two functions of angiotensin
- Increase blood pressure by vasodilation via ACE
2. Stimulate adrenal cortex to secrete aldosterone
Adrenal medulla produces
Ephinephrine and norepinephrine. These are peptide hormones called catecholamines.
Exocrine functions of pancreas
Secretes amylase, lipase, and trypsin (protein) into the duodenum
Three regions of the islets of Langerhans
Alpha beta and delta
Part of pancreas that secretes endocrine hormones
Islets of Langerhans
Alpha cells in pancreas secretes
Glucagon
Beta cells in pancreas secrete
Insulin
Delta cells in pancreas secrete
Somatostatin
Glucagon is released during
Times of famine
Glucose in the urine is a sign of
Diabetes or hyperglycemia
Type 1 diabetes is caused by
Autoimmune destruction of beta cells
Four hormones that can increase blood glucose
Glucagon, GH, glucocorticoids, an epinephrine
Somatostatin causes
Inhibition of insulin and glucagon
FSH in men causes
Stimulation of Sertoli cells necessary for sperm maturation
LH in men causes
Interstitial cells to produce testosterone
Ovaries produce which two hormones
Estrogens and progesterone
Estrogen (released by what and responsible for what)
High levels of FSH and LH. Responsible for secondary sex characteristics, thickening of endometrium, development of reproductive tract in embryo
Two places estrogens are released by
Ovarian follicles and corpus luteum
Progesterone in women is stimulated by
Increased LH stimulation
Three places progesterone is released by
Ovaries and corpus luteum (and eventually placenta when corpus luteum disintegrates)
Progesterone in women is responsible for
Maintenance of endometrium
Four phases of menstrual cycle
- Follicular
- Ovulation
- Luteal
- Menstration
Follicular phase
Flow stops. Increased GnRH cause higher levels of FSH and LH. Several ovarian follicles are developed. Follicles secrete estrogen, FSH and LH stop. Estrogen regrows endometrial lining
Ovulation is triggered by
LH surge at mid cycle caused by high levels of estrogen
The pill works by
Giving estrogen and progesterone which inhibits LH and FSH release inhibiting ovulation
The corpus luteum is formed when
After ovulation, LH causes the ruptured follicle to form corpus luteum
Purpose of corpus luteum
Secretes progesterone to maintain uterine lining. Progesterone levels rise (estrogen levels are already high). This inhibits LH and FSH
Without hCG to stimulate the corpus luteum
Progesterone levels decline an uterine lining is diminished
HCG is secreted by
Blastocyst and the developing placenta
HCG levels ____ after the first trimester but estrogen and progesterone _____ because ______
Drop, rise because the placenta starts secreting it
FSH peaks during
Ovulation
FSH and LH levels are usually _____ in postmenupausal women because _____
Increased because the feedback mechanism no longer exists
The pineal gland releases
Melatonin for sleep
Erythropoietin is released by the ____ in response to
Kidney, low oxygen levels in the blood. Patients with chronic kidney disease can become anemic because of improper red blood cell production
Protein hormones work by
Binding to receptors causing a secondary messenger cascade catalyzed by adenylate Cyclades.
Actions of cAMP are terminated by
Phosphodieterase
Do protein or peptide hormones work for a longer period of time
Steroid
All steroid hormones are derived from
Cholesterol
Steroid hormones act at the level of
DNA transcription
Three amino acid derivative hormones
Epinephrine, norepinephrine and thyroxine
Steroid hormones
Glucocorticoids mineralcorticoids and androgens
Thymus gland
Plays a part in T lymphocyte development and differentiation. Thymus is gone by adulthood