Lecture 8 Flashcards
In the polyphospho inositide system G protein exchanges
GDP for GTP and activates phospholipase C
Phospholipase C cleaves PIP2 into three molecules
Arachidonic acid, IP3, and Diaclyglcerol
IP3 gets broken down to
IP4
IP3 and IP4 promotes the release of
Calcium in different ways
In the PPI system ca in the cell favors the activation of
Guanylyl Cyclase, which convert GTP to cGMP
In the ppI system cGMP activates
Kinase G
Kinase G will activate
Some transcription factor which will lead to change in generic levels
IP3 goes to the —– and promote the release of —–
SER calicstome ….ca
IP4 opens……channels in the cell membrane
Ca
DAG activates
Protein kinase C by directing the protein to the cell’s membrane by trafficking protein. It is only activated when it is on the cells membrane
leptin receptor
it is pleiothropic, it can either activate other enzyme or it can activate or phosphorylate transcription factor directly. it also affect diet, BMI, and appetite control… it is produce by adipocytes
leptin receptor are directly linked to
the jak2 which autophosphorylate or trans phosphorylate when leptin is bind to the leptin receptor. then the JaK2 phosphorylate other protein.
receptor/ enzyme are in the ……. when it is not attached to it ligan
inactivated form
second messenger have 3 origins which are
it can be synthesized within the cell (cAMP or cGMP)
it can released within the cell by organelle(Ca from SER)
it can be imported from its external
environment ( ca though the ca channel)
second messengers
a sudden increase of a molecule in the cytoplasm after a substrate had bind to its receptor on the cell membrane or with in the cyctoplasm
divergent signaling pathway
one substrate that can affect two different receptor that hass different signaling cascades leading to two different responses
example divergent signaling pathway
salivary gland, the hormone can either bind to the beta or alpha cells of the gland. if it binds to alpha cells there will be a rise of ca in the cytoplasm which leads to secretion of fluid. if it binds to the beta cells there will be increase of the cAMp which cause release of more amylase
Convergent signaling pathway
one substate that can affect two different receptors signaling cascades leading to the same response.
example of convergent signaling pathway
Liver cells…. substrate can bind to different receptor, one which cause a rise in ca level in the cytoplasm and the other causes a rise cAMP in the the cytoplasm, which will lead to glycogenlysis
Neuro endocrine System
composed of specialized neuron that secrets Neuro hormone aka neuro-seretion. there are no synaptic connection between the neuron. the secretion goes into the blood stream in vesicles
neuro-secretion goes into the blood vessel mainly
capillaries and acts like a hormone
Neurohemal organ
is a collection of secretory neuron and its blood vessel, ADH, pituitary Gland (hypoPhysis ) and Hypothalamus found in the floor of the third ventricle
infundibulum
the stem that connects the pituitary gland to hypothalamus
the hypothalamus is located at
the base of the brain
infundibulum is formed by
the neural portion of the hypothalamus grows downward during development. some of these neuron will become the posterior lobe( neurohypophyseal) of the pituitary gland
the Rathke ‘s Pouch form
anterior lobe ( adenohypophyseal) . the rathke’s pouch is formed by the epithelial cells found on the found of the root the mouth durning development
the pituitary gland has
two region …. posterior lobe (neurohypophyseal) and anterior lobe (adenohypophysis) and a par intermedia
posterior lobe
is the neural portion of the pituitary gland. it is further divided to several part
pars nervosa
the base of the neurohypophyseal
Anterior lobe( Adenohypophysis)
aka pars distalis is the epithelial portion of the pituitary gland that is derived from the epithelial cells found on the roof of the mouth
pars intermedia
is also made of epithelial cells that secrets MSH( melanocytes stimulating hormone)
melanocytes stimulating hormone
is involved with pigmentation
the hypothalamus is made of
several aggregation of nuclei… nucleus are only i the brain. they are collection of nerve cell body in the central nervous system
SON supra optic nucleus
this is found in the hypothalamus, that is a secretory neuron that releases ADH. the neural secretion will then diffuses to the capillary found to the ends of the secretory neuron’s axon
Para ventricular nucleus (PVN)
a nuclei found in the hypothalamus that secrets oxytocin
Releasing Factors
are released by special neurons found in the hypothalamus that regulate neural secretion.
Median eminence
collection of capillaries found in the hypothalamus that picks up releasing factors release by the special neuron found around the nuclei.
hpothalamo-hypophyseal portal vein .
where the capillary give rise to a vein that brings the releasing factor from the median eminence down to a collection of capillaries found in the anterior lobe of the pituitary gland
A portal system
means when there are capillaries that bring the blood to a vein then back to capillaries
acidophils
cells that picks up acidic dye
basophils
cells that picks up basic dye
chromophobes
does not have acidic or basic dye
there are five cells identified in the adenohypophysis
somato trophs, cortico trophs, thyroid trophs, Gonado trophs , lactotrophs.
Somato Trophs
produce growth hormone called somatotrophin, and human growth hormone. it affects body growth, stimulates the secretion of somato medins and IGF( insulin-like growth factor 1), plays a role in glycolysis and break down of fats from tissue , and inhibits insulin.
Cortico Trophs
release ADTCH or adrenal tropin, it release glucocorticoids, the adrenal glands are mostly affected by these hormones, it stimulates glucocorticoids that maintain the adrenal corticoid
thyroid Trophs
produces a thyroid stimulating hormone (TSH). its function is to affect the thyroid to release T3 and T4
Gonado Trophs
produces a glycoprotein, FSH, LH also called gonado tropins . affects the physiology of gonads of bothe sexs, the reproductive tract, child birth, and development.
lacto trophs(mammal Troph)
produce a hormone called lactin, that stimulates the mammary gland and the development of milk secretion and production
releasing factor pathway
Neuro gasgular control mechanis, hypothalamus, media eminence, hypophysial portal vein, and into the capillary beds
there are four stimulating releasing factors
GHRH, TRH,GNRH, CRH
GHRH Growth hormone releasing Hormone
promotes the release of growth hormone release by the Somatotrophs causes the release of Gonadothropic hormones FSH and LH
TRH thyroid releasing hormone
affects the thyroid trophs to release TSH
GNRH gonado tropic releasing homones
stimulate FSH, LH releasing cells
CRH cortical releasing Hormone
stimulate the cortico trophs to release ACTH
Inhibitor releasing factor
growth hormone cells, prolatin cell
growth hormone cells
release somato stain that inhibit the release and synthesis of growth hormone
prolactin cell
inhibited by dopamine
GRH, prolactin,MSH affects
only the somatic tissue of the body
FSH, LH, ACTH, and TSH affect
specific endocrine glands
the pathway of hypothalamus to pituitary to releasing the hormone are controlled by
negative feed back
long loop feedback
if there is too much of the hormone, the hypothalamus cuts the stimulation of the pituitary gland which then stop the release of the different somatic tissue hormone
the short loop feedback
when the hormone directly affects he pituitary gland itself
