ENDO Flashcards
Portal system structure
portal system-capillaries->vein->enter another capillary bed provides rapid delivery of controlling hormones from hypothalamus to anterior pituitary
GnRH does
controls release of LH and FSH from gonadotroph cells.
GnRH
Gonadotropin releasing hormone
GnRH purpose and target organ
stimulates LH+FSH in ant pituitary
GnRH->ant. Pituitary gonadotrophs->LH+FSH->gonadotropin->ovaries/testes
GnRH and FSH inhibited by
GnRH and FSH are inhibited with negative feedback loop @hypothalmus/gonadotrophs by increased levels of estrogen in women/testosterone in men
PRH purpose and target organ
Prolactin releasing hormone->ant. Pituitary lactotrophs->prolactin releasing hormones go to mammary glands.
PRH
Prolactin releasing hormone
PRH inhibited by
inhibited by Prolactin inhibiting hormone/PIH. PIH structurally a dopamine and regulated by estrogen
CRH
corticotropin releasing hormone
CRH purpose and target organ
stimulates ACTH to be released.
Hypothalamus->CRH->ant. Pituitary corticotrophs->ACTH/corticotropin->adrenal cortex(zone fasciculata)->cortisol
CRH inhibited by
Cortisol negative feedback to corticotrophs and hypothalamus to inhibit CRH and ACTH
TRH stimulates
Production of TSH
TRH:
Thyrotropin releasing hormone
TRH purpose and pathway
stimulate production of TSH
Hypothalamus->TRH->ant. Pituitary thyrotrophs->TSH/thyrotropin->thyroid(target)->T3+T4
TSH purpose
TSH stimulates thyroid to produce T3+t4
TSH
Thyrotropin
TRH inhibitor/regulator
T3+T4
GHRH
growth hormone releasing hormone
GHRH
growth hormone releasing hormones:
GHRH purpose
stimulates somatotrophs to release GH(growth hormone.
GHRH pathway
Hypothalamus->GHRH->ant. Pituitary somatotrophs->GH/growth hormone->liver-> IGF/insulin like growth factor-> blood sugar increases
IGF
Insulin-like growth factor
IGF produced in
the liver
GHRH inhibited
by GHIH/growth hormone inhibiting hormone and affected by blood glucose levels
GHIH
Growth hormone inhibiting hormone
Anterior pituitary made of
Secretory tissue
2 parts of anterior pituitary
Pars distalis-bigger part
Pars tuberalis-part around the infudibulum
Anterior pituitary cell types
somatotroph
thyrotroph
gonadotroph
corticotroph
lactotroph
Anterior pituitary controlled by
hypothalamus secreting neurosecretory cells-> neurons that secrete hormones
negative feedback loops
Anterior pituitary major hormones and organ targets
Thyroid gland: thyroid stimulating hormone/TSH/thyrotropin
Liver: Human growth hormone/hGH/somatotropin (insulin like growth factor
Adrenal cortex: adrenocorticotropic hormone/ACTH/corticotropin
Ovaries/testes: Follicle stimulating hormone/FSH
Ovaries/testes: luteinizing hormone/LH
Thyrotroph cell purpose
: makes thyroid stimulating hormone/TSH/thyrotropin (tropic hormone) helps control thyroid (stimulate)
Gonadotroph cell purpose
Gonadotrophs make 2 different hormones: LH/luteinizing hormone + FSH follicle stimulating hormone known as gonadotropins stimulates gonad secretion of estrogen, testosterone
Lactotroph cell purpose
Lactotrophs make prolactin/PRL: in mammary glands promotes milk production
Corticotroph cell purpose
Corticotrophs make ACTH/adrenocorticotropic hormone/corticotropin. Target is Adrenal gland: adrenal cortex (zone fasciculata) stipulates secrete glucocorticoid hormones
Posterior pituitary made of
Neural tissue
Posterior pituitary purpose
Store and release hormones made in the hypothalamus that it received via the hypothalamohypophyseal tract
Oxytocin
Stored in posterior pituitary. produced by paraventricular nucleus of the hypothalamus
ADH
Antidiaretic hormone/vasopressin
Vassopressin
ADH/antidiuretic hormone
ADH/Vassopressin
stored in posterior pituitary. made by the supraoptic nucleus in the hypothalamus.
how do hormones enter blood stream from pituitary gland
pituitary hormones are secreted and the capillaries in the infundibular process absorb the into the boodstream
how do hormones enter blood stream from pituitary gland
pituitary hormones are secreted and the capillaries in the infundibular process absorb the into the boodstream
Oxytocin target
uterus (increase contractions)
mammary glands (release milk)
Males contraction of prostate gland
ADH target
kidneys: decrease urine production. triggers kidneys to reabsorb water,
sudoriferous/sweat glands (reduce sweating)
Arterioles (constrict to help maintain BP if blood volume is low due to dehydration/blood loss)
Pituitary dwarfism
Hyposecretion of HGH during childhood
Pituitary giganitism
hyperseretion of HGH in childhood
Acromegaly disorder
excess hGH during adult hood. large feet hands and face
Acromegaly disorder
excess hGH during adult hood. large feet hands and face
diabetes insipidus
Causes dilute urine due to ack of antidiuretic hormone usually caused by damage to pituitary. usually perpetually thirsty and prone to dehydration
Pineal gland
Tiny gland in epithalamus: secretes melatonin with decreased light
Thyroid composition
Hollow spheres=thyroid follicles
Cuboidal cells=follicle cells->line thyroid follicles
Thyroglobulin/TGB/colloid=In the middle is a gelatinous, iodine rich substance
C-cells/parafollicle cells=between follicles->produce calcitonin
Calcitonin
Secreted by C-cells/parafollicle cells in the thyroid. calcitonin is secreted when calcium levels in blood rises->triggers bone osteblasts and bone deposition(uses Ca to make bone)
PTH
Parathyroid hormone
PTH purpose
maintain Ca homeostasis. PTH secreted if there is low Ca in blood. Triggers bone break down by increasing osteoclast activity and resorption of bone tissue, increased Ca absortion from the gut and increased Ca reabsorbtion from the kidneys.
PTH antagonist
Calcitonin. Released in thyroid by c-cells
parathyroid
Secretes PTH to increase Ca in blood. posterior of thyroid. small round glands on the thyroid
Thymus
During infancy/early childhood secrets thymosin and thymopeitin, stimulates growth of T lymphocytes. gradually replaced by fat and other CT in adults
Adrenal gland zones
zona glomerulosa-outer
zona fasciculata-middle
zona reticularus-inner
Adrenal medulla-deep region
adrenal cortex
Most superficial region of adrenal gland made of glandular tissue
zona glomerulosa
outermost layer of adrenal gland. thin layer where cells are arranged in clusters.
Secretes steroids: mineralocorticoids such as aldosterone
what secretes aldosterone
secretes from zona glomerulosa of the adrenal gland.
zona fasciculata
middle zone of the adrenal gland. cells stacked on top of each other, appears columnar
secretes glucocorticoids such as cortisol
Cortisol
regulates stress response, blood glucose, gluid homeostasis and inflammation. secreted by zona fasciculata(middle) of the adrenal gland
Aldosterone
Regulates fluid and electrolyte homeostasis
secreted by the outer zona glomerulosa of the adrenal gland
Zona reticularis
innermost zone of the adrenal gland. stains darker and tightly packed.
secretes glucocorticoids and steroids called gonadocorticoids that affect gonads and other tissues
gonadocorticoids
affect gonads and other tissues.
secreted by Innermost zone: zona reticularis of the adrenal land
Adrenal medulla
Deep region of the adrenal gland. made of post synaptic sympathetic neurons that secrete epinephrine and norepinephrine in response to sympathetic stimulation
Epinephrine/norepinephrine secreted
Adrenal Medulla/deep region of the adrenal cortex. (adrenalin)
Pancreas recognition
Pancreatic islets surrounded by acinar/exocrine cells
pancreas secretes
insulin and glucagon: regulates blood glucose levels
Insulin
triggers the uptake of glucose by cells->blood glucose goes down. secreted by the pancreas
Glucagon
triggers release of stored glucose in the liver->blood glucose goes up
Leydig cells
interstitial cells in testes produce testosterone hormone (steroid) promotes sperm cells and male sex characteristics
Testes produce
Sperm cells/male gametes produce steroid hormone testosterone
Ovaries produce
Oocytes/female gametes produce estrogen and progesterone
Estrogen
oocyte development and female sex characteristics
progesterone
prepares body for pregnancy
Hormone definition
Mediator molecule which is release by one part of the body that regulates activity of cells in another part of the body
How do hormones interact with target cells
By binding to receptors in the cell membrane (proteins and amino hormones)
Or inside the cell (longest protein and steroids/cholesterol based hormone)
endocrine gland purpose
to secrete hormones into the bloodstream to target cells with the proper hormone receptors
Paracrine diffusion
hormones released from the cell target nearby cells
Autocrine diffusion
autocrine cell releases a hormone that it also has a receptor for
Types of hormones
Amine
Peptide
protein
steroid
amine based hormone
amino acids with modified groups
water soluble
epinephrine
norepinephrine
histamine
Peptide based hormone
Short chains of linked amino acids
water soluble
oxytocin
ADH-Antidiuretic hormone
insulin
GH-growth hormone
Eicosanoids: leukotrienes
protein based hormone
long chains of linked amino acids
water soluble
cholesterol based hormone
Steroid made from lipid cholesterol
Lipid soluble (can go through cell membrane)
90% utilize a transport protein to make it water soluble to ride through the blood to the target cell
Transport protein for hormones usually produce d in
liver
Steroid hormones, typically synthesized or stored?
Synthesized on demand
How do water soluble hormones interact with the target cell
Usually binds to hormone receptors on cell membranes and trigger inner cell response: usually second messengers have kinase cascade
Factors that determine target cell response
Hormone concentration in the blood
Amount of target receptors for the hormone on the cell
Influence of other hormones: synergistic/antagonistic
3 ways hormone secretion is regulated
signals from the nervous system
changes in blood chemical composition
Tropic hormones: hormones that cause another hormone to be secreted in an endocrine gland
Hypothalamus location
Under the thalamus next to the pituitary gland
Hypothalamus purpose
Considered the master regulator: major link between the nervous system and endocrine system. Regulates the release of pituitary hormones
How does the hypothalamus regulate the anterior pituitary
Hypophyseal portal system connects the hypothalamus to the anterior pituitary
Hypophyseal portal system
capillaries in the hypothalamus secrete into a vein which enters the Ant. pituitary which has capillaries around the same vein. provides rapid delivery of controlling hormones
Hormones sent from the hypothalamus to the Ant. Pituitary
GnRH: gonadotropin releasing hormone
PRH: Prolactin releasing hormone
CRH: corticotropin releasing hormone
TRH: thyrotropin releasing hormone
GHRH: growth hormone releasing hormone
GnRH
Gonadotropin releasing hormone: controls the release of LH (luteinizing hormone) and FSH (follicle stimulating hormone) which target the testes/ovaries
secreted by the hypothalamus
LH
Luteinizing hormone: plays an important role in women sexual development triggers steroid production in ovaries
helps control menstrual cycles and triggers the release of the egg
Men: triggers leydig cells to produce testosterone in the testes.
FSH
Follicle stimulating hormone:
Women: helps regulate menstrual cycle. stimulates egg production in ovaries
MEN: help control the production of sperm in testes
PRH
Prolactin releasing hormone: stimulate prolactin release. prolactin target mammary glands to stimulate milk production
CRH
Corticotropin releasing hormone: stimulates ACTH (adrenocorticotropic hormone) release
ACTH target is zona fasciculata in the adrenal gland to produce cortisol
ACTH
adrenocorticotropic hormone secreted by -ant. pituitary
ACTH target is zona fasciculata in the adrenal gland to produce cortisol
TRH
Thyrotropin releasing hormone secreted by the hypothalamus to the ant. pituitary
TRH->stimulates TSH (thyrotropin) release from ant. pituitary thyrotrophs. target of TSH is thyroid to release T3 And T4
TSH
TSH=Thyrotropin-secreted by ant. pituitary: target is thyroid to release T3 and T4
GHRH
Growth hormone releasing Hormone secreted by the hypothalamus. stimulates somatotrophs to release GH-growth hormone
GH targets the liver to release IGF-1
GH
Growth hormone-secreted by the Ant. Pituitary somatotrophs
Target is the liver to release IGF-1 (insulin like growth factor) and increase blood sugar
IGF-1
Insulin like growth factor. secreted by the liver and increases blood sugar in response to GH
GHIH
Growth hormone inhibiting hormone inhibits GHRH. Both GHIH and GHRH are affected by blood glucose levels
Pituitary gland made of
secretory tissue makes it up
Pituitary gland is known as
The hypothesis about pH
Pituitary gland location
in the hypothesis fossa of the sphenoid bone attached to the hypothalamus by the infundibulum
Anterior pituitary known as
adeno hypothesis
Anterior pituitary is controlled by
the hypothalamus secreting tropins and negative feed back loops
Ant. pituitary Hormones that target the thyroid gland
TSH (thyroid secreting hormone) secreted by thyrotrophs
Thyroid gland secretes what on response to TSH
T3+T4
T3 +t-T4 affects
Acts on all cells in the body to increase metabolic rate, increase protein synthesis and regulate HR and BP
T4 is converted to T3 if blood volume drops
Ant. pituitary Hormones that target the Liver
GH(growth hormone) secreted from somatotrophs in the Ant. Pituitary targets the liver which secretes IGF-1 insulin like growth factor
Ant. pituitary Hormones that target the adrenal gland
ACTH (adrenocorticotropic hormone) secreted by corticotrophs in response to CRH (corticotropin releasing hormone) from the ant. pituitary
Liver secretes what in response to GH
IGF-1 insulin like growth factor
adrenal gland secretes what in response to ACTH
Adrenal cortex secretes different chemicals in different zones. zona glomerulosa->mineralcorticoids like aldosterone which regulate fluid and electrolyte homeostasis
zona fasciculata-> glucocoticoids like cortisol
zona reticularus->glucocorticoids and steroids called gonadocorticiods that affect gonads and other tissues
