Endo Lec 2 Flashcards
anatomy from hypothalamus to pituitary
- hypothalamus
- median eminence
- pituitary stalk (connected directly to.. ppg)
- posterior pituitary gland
- anterior pituitary gland
anterior pituitary (other name)
adenohypophysis
posterior pituitary (other name)
neurohypophysis
pituitary stalk (other name)
infundibulum
adenohypophysis (type of tissue in embryonic development)
-from mouth upward
neurohypophysis (type of tissue in embryonic development)
-neural tissue downward
portal system (def.)
-two capillary beds connected by veins without first going through the heart
hypothalamic-hypophyseal portal system (def.) and has..plexus (type of blood entering/exiting)
- blood system that connects hypothalamus + anterior pituitary
- primary plexus (arterial blood enters) + secondary plexus (venous blood exits)
hypothalamic-hypophyseal portal system (main function)
-transport hormones between the hypothalamus and anterior pituitary gland
relationship between hypothalamus and anterior pituitary
- neurosecretory neurons send neurohormones in primary plexus (in hypophyseal system) into secondary plexus,
- neurohormones acts on endocrine cell in anterior pituitary which release hormones into the secondary plexus(vein)
secondary plexus of hypophyseal vein is located
in anterior pituitary gland
primary plexus of hypophyseal vein is located
top of pituitary stalk near hypothalamus
ADH is made in … and secreted from
- supraoptic nucleus (SON)
- posterior pituitary
oxytocin is made in … and secreted from
- paraventricular nucleus (PVN)
- posterior pituitary
SON stands for …
supraoptic nucleus
PVN stands for …
paraventricular nucleus
SON and PVN are
group of neurosecretory neurons
relationship between hypothalamus and posterior pituitary
- neurosecretory neurons send hormones to posterior pituitary through axon in hypothalamic-posterior pituitary stalk
- hormones released into blood system directly in posterior pituitary
6 hormones of the anterior pituitary gland
- follicle-stimulating hormone
- luteinizing hormone
- adrenocorticotropic hormone
- thyroid-stimulating hormone
- prolactin
- growth hormone
2 anterior pituitary hormones that are secreted from the same cell types
FSH
LH
FSH stands for
follicle-stimulating hormone
LH stands for
luteinizing hormone
ACTH stands for
adrenocorticotropic hormone
TSH stands for
thyroid-stimulating hormone
PRL stands for
prolactin
GH stands for
growth hormone
FSH main target(s)
ovaries + testes
LH main target(s)
ovaries + testes
ACTH main target(s)
adrenal cortex
TSH main target(s)
thyroid gland
PRL main target(s)
mammary gland
GH main target(s)
most tissues (eg. bone)
all 6 anterior pituitary hormones belong to … family and come from…
protein and come from different cell types
6 hormones of the hypothalamus
- gonadotropin releasing hormone
- corticotropin releasing hormone
- thyrotropin releasing hormone
- growth hormone releasing hormone
- growth hormone inhibiting hormone/somatostatin
- prolactin inhibiting hormone/dopamine
all hypothalamic hormones except … are …
except PIH are peptides
growth hormone inhibiting hormone (other name)
somatostatin
prolactin inhibiting hormone (other name)
dopamine
GnRH stands for
gonadotropin releasing hormone
CRH stands for
corticotropin releasing hormone
TRH stands for
thyrotropin releasing hormone
GHRH stands for
growth hormone releasing hormone
GHIH or SS stands for
growth hormone inhibiting hormone/somatostatin
PIH or DA stands for
prolactin inhibiting hormone/dopamine
GnRH effect on anterior pituitary hormone(s)
increases LH and FSH secretion
CRH effect on anterior pituitary hormone(s)
increases ACTH secretion
TRH effect on anterior pituitary hormone(s)
increases TSH secretion
GHRH effect on anterior pituitary hormone(s)
increases GH secretion
GHIH/SS effect on anterior pituitary hormone(s)
decreases GH secretion
PIH/DA effect on anterior pituitary hormone(s)
decreases PRL
hypothalamus-pituitary-target gland axis
-inputs (higher centres) –>hypothalamus –> hypothalamic hormones–> anterior pituitary–> ant. pit. hormones–> target gland–> tagret gland hormones
short-loop feedback system
-negative feedback in hypothalamus-pituitary-target gland axis where ant. pit. hormones affects release of hypothalamic hormones
long-long feedback system
-negative feedback in hypothalamus-pituitary-target gland axis where target gland hormones affects release of ant.pit + hypothalamic hormones
prolactin undergo which type of feedback system
-short-loop feedback system
growth hormone undergo which type of feedback system
-short-loop feedback system
most abundant anterior pituitary hormone
growth hormone
growth hormone is a (type of hormone)
protein hormone
GH acts on … and is associated with
cell surface receptors and it associated with protein kinase activity
GH secretion time frame
secreted throughout life
GH promotes growth mainly..
after birth (not in fetal stage)
GH- type of secretion?
pulsatile secretion (secreted in pulses)
GH does what? (2 things)
- increases growth of most tissues, especially bone
- affects metabolism
GH secretion follows .. rhythm
circadian
GH action in vitro
no growth
GH action in vivo
GH creates insulin-like growth factor (IGF-1) that mediates tissue growth
How does bone grow longer?
progenitor cells (fibroblasts) undergo differentiation into cartilage cells (chondrocytes) which proliferate and undergo ossification and turn into bone
effects of GH on metabolism
-increases protein synthesis and increases growth of most tissues
GH effects on fats (2)
- GH increase lipolysis
- increase free fatty acids for energy
GH effects on carbohydrates (2)
- GH decreases glucose uptake into muscles (anti-insulin like effects)- hyperglycemia
- increase gluconeogenesis by liver
GH effects on proteins (4)
- GH increases a.a uptake into cells
- increase protein synthesis
- increases cell size (hypertrophy)
- increases the number of cells in connective tissues (hyperplasia)
diabetogenic hormone causes
hyperglycemia
hyperplasia is
enlargement of an organ or tissue caused by increase in number of cells
hormonal factors that increase GH secretion
GHRH
hormonal factors that decrease GH secretion
- somatostatin
- GH
- IGF-1 (Insulin-like growth factor 1)
metabolic factors that increase GH secretion
- hypoglycemia
- increase in aa in blood
metabolic factors that decrease GH secretion
- hyperglycemia
- increase in fatty acids
other factors that increase GH secretion
- deep sleep
- acute stress (ex. exercise)
other factors that decrease GH secretion
-chronic stress (ex. prolonged malnutrition)
IGF-1 (Insulin-like growth factor 1) secreted by
liver
Too much GH (2 conditions)
- gigantism
- acromegaly
gigantism occurs in .. and growth occurs in…
- children
- whole body
acromegaly occurs in .. and growth occurs in…
- adults
- jaw, thickening of bone, feet, course features
Too little GH condition
-dwarfism
Dwarfism in children, stunted growth is due to
- decreased GHRH release
- decreased GH synthesis and secretion
Laron dwarfism is due to
mutation of GH receptors
metabolic effects of too much GH
-hyperglycemia
hormones of posterior pituitary gland (2)
- ADH (antidiuretic hormone) or vasopressin
- OXY (oxytocin)
increase in osmolarity of ECF (dehydration)- effect on ADH
-osmoreceptors in hypothalamus trigger SON, release ADH from posterior pituitary which acts on kidney and increases water reabsorption= decrease in osmolarity of ECF
decrease of ECF/BP (dehydration)- effect on ADH
-baroreceptors in cardiovascular system trigger SON, release ADH from posterior pituitary which acts on kidney and increases water reabsorption= increase in volume of ECF and BP
too much ADH symptoms
- increased water retention
- increased blood volume (syndrome of inappropriate antidiuretic hormone secretion)
SIADH stands for
syndrome of inappropriate antidiuretic hormone secretion
too little ADH symptoms
-central/nephrogenic diabetes insipidus (large volume of dilute urine)–> nephrogenic (abrononal ADH receptors- large amounts of ADH in system)
factors affecting oxytocin secretion
- parturition
- lactation
parturition- effect on oxytocin secretion
-cervical stretch send signals to posterior pituitary and causes uterine contractions (positive feedback)
suckling- effect on oxytocin secretion
-suckling send signals to posterior pitaya and oxytocin in released to cause lactation
source of ADH/vasopressin (in hypothalamus)
supraoptic nucleus (SON)
targets of ADH/vasopressin (2)
kidneys, blood vessels
source of oxytocin (in hypothalamus)
paraventricular nucleus (PVN)
targets of oxytocin (2)
uterus, mammary glands
