Endocrinology Flashcards
What is a peptide hormone
Made from amino acids
Act on effector cell membrane receptors and initiate internal secondary messenger cascades
*water soluble in the blood
How are peptide hormones made
Synthesized in the RER as preprohormones which are cleaved into prohormones and move to Golgi apparatus for modification into peptide hormones
Packed in secretory vesicles for release via exocytosis
What are steroid hormones
Derived from cholesterol in the smooth ER and mitochondria
Insoluble in water so require proteins for transport in the blood
How do steroid hormones have an effect on gene expression
Bind to protein to move through blood stream then they cross the cell membrane of the effector cell and bind to a receptor in the cytosol
The cytosol is receptor and the steroid complex move into the nucleus and influence gene expression
Compare peptide to steroid hormones
Peptide are fast acting short lived, water soluble
Steroid are slow acting long lived, non water soluble
What are tyrosine derivative hormones
Lipid soluble hormones derived from the amino acid tyrosine
Hydrophobic and hydrophilic properties
How do tyrosine derivative hormones work
One type is like steroid hormones
The catecholamines epinephrine and norepinephrine are like peptide hormones
Tropic vs direct peptide hormone
Tropic has another gland as its target
Direct has an organ as its target
How do hormones go from the hypothalamus to the pituitary
To the anterior pituitary vis the blood stream - hypothalamic hypophyseal portal system
To the posterior pituitary via nerve axons
What are the 2 direct peptide hormones that neurosecretory cells of the hypothalamus synthesis
Vasopressin
Oxytocin
Which hormones does the posterior pituitary synthesize
It doesnt! It only stores hormones oxytocin and vasopressin
What does vasopressin (ADH) do
Increased water reabsorption in the kidney tubules
Makes you not pee
What inhibits ADH
Caffeine and alcohol
What does oxytocin do
Secreted during child birth for uterine contractions
Stimulates milk secretion
What is somatostatin
Tropic peptide hormone made in hypothalamus that inhibits the release of GH and TSH
Which hormones does the anterior pituitary synthesize and release
FLAT PEG FSH LH ACTH TSH PRL Endorphins GH
Describe how growth hormone works
GHRH growth hormone releasing hormone made in the hypothalamus stimulates GH release which stimulates all cells for growth
releasing = tropic
Describe how adrenocorticotropic hormone works
Stimulated by CRH from hypothalamus
It works as tropic peptide hormones to stimulate the adrenal cortex to synthesis and secrete glucocorticoids during stress
How does thyroid stimulating hormone work
Stimulated for release by TRH from hypothalamus
Acts as tropic peptide hormone and stimulates thyroid glad to increase in size, absorb iodine and synthesize thyroid hormone
How does a lack of iodine effect the thyroid feedback loop
If no iodine , insufficient T3 and T4 will be produced so there will be no inhibition of TRH and the thyroid will continue to grow resulting in goiter
How is the release of luteinizing hormone stimulated
Estrogen stimulates GnRH gonadotropin releasing hormone from the hypothalamus to release LH
Estrogen and progesterone of the corpus luteum inhibits the release of GnRH
What is the function of LH
Tropic peptide hormone
In females - stimulates ovulation and formation of corpus luteum
Males - stimulates testes to synthesize testosterone
How is FSH regulated
Stimulated by GnRH which is stimulated by estrogen
Inhibited by estrogen and progesterone of corpus luteum
What is the function of FSH
Tropic peptide
Females- maturation of the ovarian follicles
Males - maturation of the seminiferous tubules for sperm production
How does prolactin work
Stimulated by TRH or by inhibiting dopamine
Direct peptide hormone promotes lactation in the breasts ***not secretion that’s oxytocin
What do endorphins do
Direct peptide hormones that inhibit the perception of pain
Which hormones of the anterior pituitary are direct acting q
Growth hormone
Prolactin
Endorphins
PNS innervates every gland in the body but
Sweat glands
What does the adrenal cortex do
Responds to ACTH and synthesizes corticosteroids
What does the adrenal medulla do
Secretory cells secrete epinephrine and norepinephrine as part of the SNS
These are tyrosine derivative hormones
What are the 3 functions of corticosteroids of the adrenal cortex
Salt - mineralocorticoids - aldosterone (increase BP)
Sex - cortical sex hormones - androgens
Sugar - glucocorticoids - cortisol (increase blood glucose)
What is the effect of aldosterone in the RAAS
Increases NaCl reabsorption and K H secretion resulting in an increase in blood volume and pressure
How does the RAAS work
Blood volume decreases kidneys produce renin
Renin converts angiotensinogen to angiotensin 1 which is converted to angiotensin 2 by ACE
Angiotensin 2 stimulates adrenal cortex to secrete aldosterone
What does the thyroid gland produce
T4 T3 and calcitonin
What type of hormone are T3/4
Lipid soluble tyrosine derivatives that influence gene expression to increase basal metabolic rate
Describe calcitonin
Large peptide hormone released by the thyroid
Tones down blood calcium
Describe parathyroid hormone
Released by the parathyroid
Peptide hormone that increases blood calcium bu stimulating release from bone osteoclasts
The pancreas is an endocrine and exocrine gland what do they each do
Endocrine - secret their hormone products directly in the blood
Exocrine - secrete their products into ducts that lead into the external environment
Pancreas functions an endocrine gland by releasing peptide hormones into the blood, this function is performed by
Glandular structures called islets of langerhans which are composed of alpha beta and delta cells
What are the hormones of the pancreas and their functions
Glucagon - increases blood glucose
Insulin - decreases blood glucose
Pancreatic somatostatin - inhibitory , decreased insulin and glucagon secretion
Tool for remembering which islets of langerhan cells the pancreatic hormones come from
BAD PIGS
Beta - insulin
Alpha - glucagon
Delta - somatostatin
What is the pathway of sperm
Seminiferous tubules — epididymis — vas deferens — ejaculatory duct — urethra — penis
SEVEN UP
Describe the process of sperm cell formation
Spermatogonium 2n undergoes mitosis
Primary spermatocytes 2n undergo meiosis
Secondary spermatocytes n undergo meiosis
Spermatids n differ and mature into sperm cells
What happens during spermiogenesis
Phenotypic change from a round spermatid to a elongated sperm with a tail *no change in chromosomal complement
