Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
133 Cards in this Set
- Front
- Back
- 3rd side (hint)
Why is communication vital for any multicellular oranism? (4 reasons)
|
Maintain homeostasis; coordinate growth and development; adapt to internal and external stresses; contribute to the processes of sexual reproduction
|
|
|
Two communication systems
|
nervous and endocrine
|
|
|
Where is interaction between the nervous and endocrine system coordinated?
|
hypothalamus
|
|
|
Neuroendocrine signaling mechanism
|
neuron releases a chemical mediator not into a synapse but into one or both of the vascular systems. The mediator then affects a cell at some distance.
|
|
|
What type of vasculature is typical for the endocrine system?
|
fenestrated and sinusoidal blood capillaries
|
|
|
CT of fibrous capsule around endocrine glands
|
dense irregular connective tissue (type I collagen)
|
|
|
4 parenchymal arrangements of endocrine system
|
unicellular, cords, follicular pattern, multipolar neurons
|
|
|
what do steroid secreting glands store?
|
the hormone precursor cholesterol
|
|
|
pro-opiomelanocortin (POMC)
|
a prohormone made in several tissues in the body including the brain and pituitary that is broken down into ACTH
|
|
|
positive feedback system (loop)
|
the response enhances or intensifies the original stimulus
|
|
|
Are most feedback systems in the body positive or negative?
|
negative
|
|
|
examples of negative feedback loops
|
blood pressure, body temperature and blood glucose level
|
|
|
examples of positive feedback loops
|
blood clotting, labor contractions during childbirth and immune response that provide defence against pathogens
|
|
|
What is the source of hormones that are derivatives of tyrosine?
|
adrenal medulla, thyroid gland, and pineal gland
|
|
|
What is the source of small peptide hormones?
|
posterior pituitary, heart atria
|
|
|
What is the source of small protein hormones?
|
pancreas, anterior pituitary and parathyroid glands
|
|
|
What is the source of steroid hormones
|
adrenal cortex, ovaries and testes
|
|
|
What are examples of Eicosanoid hormones? And what is the source of them?
|
prostaglandins and leukotrienes; all cells except red blood cells
|
|
|
What does binding to plasma proteins do to circulating hormones?
|
makes them inactive
|
|
|
Endocrine organs
|
pineal, brain, ituitary, thyroid, parathyroid, thymus, adrenal gland, islets of langerhans of pancreas, parts of the ovary, testis, kidney, placenta, and heart
|
|
|
2 parts of the pituitary gland
|
neurohypophysis and adenohypophysis
|
|
|
2 parts of the neurohypophysis
|
pars nervosa and infundibulum (w/ infundibular stem and median eminence)
|
|
|
3 parts of the adenohypophysis
|
pars distalis, pars intermedia, and pars tuberalis
|
|
|
What is the embryological origin of the pituitary gland?
|
neural ectoderm (neurohypophysis) and ectoderm lining the oral cavity (adenohypophysis)
|
|
|
Two main parencymal cell types of the pars distalis of the pituitary gland
|
chromophobes and cormophils
|
|
|
Chromophobes
|
degranulated chromophil that is a parenchymal cell of the pars distalis of the pituitary gland (adenohypophysis) that is found in clusters away from the capillaries
|
|
|
chromophils
|
granulated hormone secreting cells of the adenohypophysis that are either acidophils or basophils
|
|
|
What do the acidophil type of chromophils secrete?
|
growth hormone and prolactin
|
|
|
What do the basophil type of chromophils secrete?
|
FSH, LH, TSH and ACTH
|
|
|
what is the purpose of the hypophyseal portal system
|
transport hormones from the hypothalamus to the adenohypophysis
|
|
|
2 types of small peptide hormones synthesized in the neuron cell bodies of the hypothalamic nuclei:
|
Releasing hormones and inhibiting hormones
|
|
|
GnRH
|
small peptide releasing hormone of the hypothalamic nuclei that stimulates gonadotrophs to release FSH and LH
|
|
|
CRH
|
small peptide releasing hormone of the hypothalamic nuclei that stimulates corticotrophs to release ACTH
|
|
|
TRH
|
small peptide releasing hormone of the hypothalamic nuclei that stimulates thyrotrophs to release TSH
|
|
|
GHRH (somatotropin)
|
small peptide releasing hormone of the hypothalamic nuclei that stimulates somatotrophs to release GH
|
|
|
Somatostatin
|
small peptide inhibiting hormone of the hypothalamic nuclei that inhibits growth hormone release from somatotrophs; inhibits gastrin release and is produced by δ cells of the pancreatic islets
|
|
|
Dopamin
|
small peptide inhibiting hormone of the hypothalamic nuclei that inhibits prolactin release from mammotrophs
|
|
|
Pars intermedia
|
thin layer of cells and colloid cyts next to the neural lobe of the pituitary. This region atrophies in adults
|
|
|
Pars nervosa
|
nervous tissue down-growth of the hypothalamus that makes up the posterior lobe of the pituitary gland and connects to the infundibulum. Consists of modified multipolor neurons with unmyelinated axons
|
|
|
What do the unmyelinated axons of the hypothalamohypophyseal tract contain
|
large granule-filled dilations called herring bodis along their length
|
|
|
What do the granules of herring bodies contain?
|
either oxytocin or ADH, ATP and neurophisins
|
|
|
function of neurophysins
|
low-affinity carriers for the hormones as they travel down the axon to the nerve terminal
|
|
|
Pituitcytes
|
higly branched astrocytes whose processes surround and support the axons of the hypothalamo-hypophyseal tract
|
|
|
Oxytocin
|
small peptide hormone of the posterior pituitary that stimulates milk ejection by the mammary glands and stimulates uterine smooth muscle contraction during copulation and childbirth
|
|
|
arginine vasopressin (AVP) or antidiuretic hormone (ADH)
|
small peptide hormone of the posterior pituitary that stimulates water resorption by the renal medulalary collecting duct. Regulated by the supraoptic nucleus
|
|
|
APUD cells or the diffuse neuroendocrine system cells
|
unicellular glands scattered among epithelial cells derived from neural crest that are polypeptide secreting with concentrated bioactive amines in secretory granules in their bases
|
|
|
DNES polypeptides mechanism of signalling
|
paracrine and endocrine
|
|
|
gastrin
|
digestive hormone that promotes secretion of gastric juice, increases gastric motility and promotes growth of gastric mucosa
|
|
|
secretin
|
digestive hormone that stimulates secretion of pancreatic juice and bil
|
|
|
cholecystokinin
|
digestive hormone that stimulates secretion of pancreatic juice rich in digestive enzymes and causes opening of sphincter of oddi which ejects bile from the gall bladder
|
|
|
Embryological origin of thyroid gland
|
endoderm
|
|
|
2 cell types of thyroid gland
|
follicular cells and parafollicular cells
|
|
|
What fills the lumen of the follicle of the thyroid gland?
|
colloid (mainly consists of the glycoprotein thyroglobulin)
|
|
|
What is functional activity of follicular cells stimulated by?
|
TSH from the anterior pituitary and by sympathetic nerves
|
|
|
when is TSH increased?
|
low environmental temperatures, puberty and pregnancy
|
|
|
when is TSH decreased?
|
emotional stress and systemic stress
|
|
|
What stimulates iodide uptake by follicular cells?
|
TSH
|
|
|
When endosomes combine with lysosomes in follicular cells, what is iodothyroglobulin broken down into?
|
2 hormones, T3 and T4.
|
|
|
Function of T3 and T4
|
increase basal metabolic rate (the rate at which cells use glucose), promote cell growth, increase HR, raise body temp, and enhance all energy-requiring cell functions
|
|
|
parafollicular cells
|
APUD cells of the thyroid gland that are derived from neural crest and secrete the peptide hormone colcitonin in response to high blood Ca
|
|
|
Calcitonin
|
peptide hormone secreted by parafollicular cells of the thyroid gland that inhibits bne resoprption by inhibiting osteoclasts and threby lowering blood calcium.
|
|
|
What is the embryological origin of the parathyroid glands?
|
endoderm of the 3rd and 4th pharyngeal pouches
|
|
|
2 cell types of the parathyroid gland
|
chief cells and oxyphil cells
|
|
|
What is the vasculature of the parathyroid glands
|
broad, irregular fenestrated capillaries channel the parenchymal cells
|
|
|
Chif Cells
|
most abundant parenchymal cells of the parathyroid glands that secrete parathyroid hormone
|
|
|
parathyroid hormone
|
peptide hormone that increases blood calcium by acting on bone, in kidneys and in the intestines
|
|
|
What causes activation of a vitamin D precursor in the kidney?
|
parathyroid hormone
|
|
|
Oxyphil cells
|
large parencymal cells of the parathyroid gland with many mitochondria and an unknown function
|
|
|
What shape are the adrenal glands?
|
Right: pyramid; Left: crescent shaped
|
|
|
Embryological origin of cortex of the adrenal gland
|
mesoderm
|
|
|
what does the cortex of the adrenal gland secrete?
|
3 classes of ssteroid hormones: mineralocorticoids, glucocorticoids and androgens
|
|
|
What are the 3 zones of the cortex and their primary secretion?
|
zona glomerulosa (mineralocorticoid: aldosterone); fasciculata (glucocorticoids); zona reticularis (androgens and glucocorticoids)
|
|
|
function of mineralocorticoids
|
osmotic balance and blood pressure regulation by affecting the function of renal tubules
|
|
|
Atrial natriuretic peptide
|
hormone released by the atrial cells of the heart in response to high BP and inhibits aldosterone release from the zona glomerulosa.
|
|
|
what is the vasculature of the zona fasciculata of the adrenal glands?
|
sinusoidal capillaries run between cords
|
|
|
Spongiocytes
|
cells in the zona fasciculata arranged in cords with large lipid droplets in their cytoplasm
|
|
|
What stimulates the secretion of glucocorticoids to raise BP?
|
ACTH from the anterior pituitary stimulates the zona fasciculata and zona reticularis
|
|
|
2 types of cells in the medulla of the adrenal glands
|
chromaffin and ganglion cells
|
|
|
Chromaffin cells
|
parenchymal cells of the medulla of the adrenal glands that are modified postganglionic sympathetic neurons that release epinephrine and norepinephrine
|
|
|
function of epinephrine
|
increases blood glucose, alertness, cardiac output and HR
|
|
|
function of norepinephrine
|
increases blood pressure by vasoconstriction
|
|
|
What is the physiological role of the fetal adrenal in the fetal life?
|
oto synthesize estrogen precursors which are converted in the placenta to estrogens.
|
|
|
What is the endocrine component of the pancreas called
|
islets of Langerhans
|
|
|
What is the embryological origin of the islets of langerhans?
|
endoderm and part of the DNES
|
|
|
β cells
|
parenchymal cells of the islets of langerhans that are concentrated in the center. They produce insulin in response to high blood glucose
|
|
|
α cells
|
parencymal cells that are in the periphery of the islets of langerhans and produce glucagon in response to low blood glucose
|
|
|
δ cells
|
parenchymal cells in the islets of langerhans that produce somatostatin to inhibit α cells and β cells.
|
|
|
F cells (or PP cells)
|
parenchymal cells located in the periphery of the islets of langerhan that produces pancreatic polypeptide that inhibit pancreatic exocrine secretion of enzymes and bicarbonate
|
|
|
What is the embryological origin of the pineal gland?
|
ectoderm
|
|
|
2 cell types of pineal gland
|
pinealocytes and astrocytes
|
|
|
What is the secretion of pinealocytes?
|
serotonin during the day and melatonin at night
|
|
|
What are circadian rhythms controlled by?
|
periodic release of NE by postganglionic sympathetic fibers which in turn is controlled by light perceived by the retina.
|
|
|
What is the primary site of action for melatonin?
|
hypothalamus
|
|
|
Melatonin's functions:
|
immune response, tep regulation, and possibly aging and senescence
|
|
|
What is the primary target for FSH?
|
testes
|
|
|
What does diabetes insipidus result from?
|
hyposecretion of ADH
|
|
|
What is responsible for regulating hormone release and function throughout the body?
|
the neuroendocrine system (hypothalamus, pituitary and adrenal gland)
|
|
|
Two mechanisms for inactivating hormones
|
removal of receptor area, inactivate hormone by enzyme
|
|
|
3 types of dysfunction that diseasaes associated with hormone defects cause:
|
overproduction (from tumor formation?), underproduction, or target cell insensitivity
|
None
|
|
Which glands produce peptide hormones?
|
anterior pituitary, posterior pituitary, hypothalamus and pancreas
|
|
|
Where is ACTH produced and what does it do?
|
anterior pituitary; stimulates synthesis and secretion of adrenal cortical hormones (cortisol, androgens, and aldosterone)
|
|
|
Where is prolactin produced and what does it do?
|
anterior pituitary; stimulates milk production and secretion in breast
|
|
|
Where is growth hormone produced and what does it do?
|
anterior pituitary; stimulates protein synthesis and overall growth
|
|
|
Where is Luteinizing hormone (LH) produced and what does it do?
|
anterior pituitary; stimulates testosterone synthesis, and ovulation, formation of corpus luteum, estrogen and progesterone synthesis in ovaries
|
|
|
Where is Follicle stimulating hormone (FSH) produced and what does it do?
|
anterior pituitary; stimulates sperm maturation of testes and follicular development and estrogen synthesis in ovaries
|
|
|
Where is thyroid stimulating hormone (TSH) produced and what does it do?
|
anterior pituitary; stimulates synthesis and secretion of thyroid hormones
|
|
|
Where is oxytocin produced and what does it do?
|
posterior pituitary; stimulates milk ejection from breasts and uterine contractions
|
|
|
Where is AVP or ADH produced and what does it do?
|
posterior pituitary; stimulates water reabsorption in principal cells of collecting ducts and constriction of arterioles
|
|
|
Where is calcitonin produced and what does it do?
|
thyroid (parafollicular cells); decreases serum Ca2+
|
|
|
What does PTH do?
|
parathyroid hormone increases serum Ca2+
|
|
|
Where is insulin produced and what does it do?
|
β cells of pancreas; decreases blood glucose
|
|
|
Where is glucagon produced and what does it do?
|
α cells of pancreas; increases blood glucose
|
|
|
Where is renin produced and what does it do?
|
kidney; catalyzes conversion of angionesinogen to angiotensin I
|
|
|
What does a pre-prohormone contain at it's N-terminus and why?
|
a 15-25 residue signal sequence of mostly hydrophobic aa that allows entry of the pre-prohormone into the ER
|
|
|
How are peptide hormones received by cells?
|
receptor mediated endocytosis and then hormone and receptor are degraded by lysosomal proteases
|
|
|
What does POMC become?
|
ACTH
|
|
|
How are peptide hormones released?
|
by the regulated secretory pathway; requires stimulus (releasing hormone that causes depolarization of PM, then an influx of Ca2+ for the release of hormone)
|
|
|
What are prohormones packaged in?
|
immature secretory granules (IMG)
|
|
|
How is ACTH inhibitted (and where)
|
feedback inhibition by cortisol (anterior pituitary, hypothalamus) and negative inhibition by dopamine (anterior pituitary)
|
|
|
Cushing's syndrome
|
a peptide hormone disease that is an adenoma of the adrenal cortex that releases excess cortisol
|
|
|
Cushing's disease
|
pituitary-acth secreting tumors, most common form of cushings syndrome
|
|
|
what are the 4 types of diabetes insipidus?
|
nephrogenic, gestational, dipsogenic, and neurogenic (most common)
|
|
|
what is diabetes insipidus characterized by?
|
polyuria and polydipsia,
|
|
|
What does iodination of tyrosine residues in thyroglobulin produce?
|
monoiodoyrosine (MIT) and diiodotyrosine (DIT)
|
|
|
Is T3 or T4 more active?
|
T3
|
|
|
Where are MIT and DIT synthesized? And by what?
|
the follicular cells of the thyroid gland, by the enzyme thyroidal peroxidase
|
|
|
How are MIT and DIT stored?
|
thyroglobulin
|
|
|
Where is thyroglobulin iodinated?
|
colloid space of follicular cells
|
|
|
What is the major site of degradation of T4 and T3?
|
liver
|
|
|
Exophthalmos
|
protruding eyes, caused by hyperthyroidism
|
None
|
|
What are the symptoms of hypothyroidism?
|
lowered basal metabolic rate, diastolic hypertension, and goiter
|
|
|
levothyroxine
|
treatment for hypothyroidism
|
|
|
what is the cause of hyperthyroidism
|
autoimmune. There are antibodies to TSH receptors
|
|