Lecture 7: Metabloism 5 (endocrine system 2) Flashcards
what type of cells is the th gland composed of?
follicular and parafollicular cells
follicular cells are stimulated by ___ to produce what? what are they known as? what is their function
TSH
thyroxine and triiodine - thryroid hormones
- to increase BMR
- help maintain normal body temp
- stimulate protein synthesis
- incr the use of glucose and fattty acids for ATP production
- upregulate beta receptors that attach to catecholamines
- work with hGh and insulin to accelerate body growth
parafollicular cells produce ____. what does this hormone do?
calcitonin
- helps regulate Ca++ homeostasis by stimulating osteoblasts (bone formation) and inhibiting osteoclast (breakdown of bones) activity, which lowers the level of calcium in the blood
what are some other functions of calcitonin?
- inhibits Ca++ reabsorption in the kidney (excreted in urine)
- lowers Ca levels in blood
- inhibits Ca++ absorption by intestines
how many lobes does the parathyroid have? how many glands?
4
2 - inferor and superior
the parathyroid gland contains which type of cells? what are they responsible for?
chief/principal cells
producing pth
the parathyroid acts to?
- inc the # and activity of osteoclasts (breakdown of bone)
- increases the rate of calcium and mg rabsopriotn in kidneys
- printers formation of calcitriol in kidneys (inc the absorption of Ca and Mg from GI tract
what are the three main types of hormones secreted by the adrenal cortex?
- glucocorticoid (regulate mineral homeostasis)
- mineralocorticoids (affect glucose homeostasis)
- androgens (masculinities effects)
which hormone is the major mineralocorticoid? what pathway helps regulate aldosterone secretion
aldosterone, helps regulate Na and K homeostasis
the RAA
what are glucocorticoids (cortisol) regulated by? what does it help to control
release of corticotropin releasing hormone
- protine breakdown
- glucose formation
- lipolysis
- resistance to stress
- inflammation
- immune responses
cortisol (glucocorticoid) is aka. ____? what does this mean
stress hormone
body is in constant flight/fight, this doesn’t allow the body to repair, slow down, and rebuild
- break everything (muscles) down to get away
- this constantly impacts bone formation, muscles, and fat
what does cortisol do in certain parts of your body?
muscle - decrease amino acid uptake by muscle
liver - glucose gen
bone - reduces bone formation
adipose tissue - promote breakdown of fat
pancreas - cortisol counteracts insulin
what is the adrenal medulla stimulated by?
sympathetic NS to secrete catecholamines such as epi/norepi both of which are involved in fight/flight response
what is the difference between epi and norepi
norepi is directly released by sympathetic neurons, therefore its produces a quicker response than epi (released by the medulla)
explain which pathway (epi/norepi) work best for an individual with a heart transplant
can’t reattach neurons but can attach blood vessels
- completely reliant on epi, so it takes longer for HR to increase during exercise
what are the catecholemines
epi and norepi
the pancreas can be classified as both?
an endocrine and exocrine gland
what doe the exocrine glands of the panc produce? how are they delivered
digestive enzymes that are delivered to the GI tract though ducts
what are pancreatic islets? what do they do?
clusters of endocrine tissues among the exocrine cells
produce insulin and glucagon
The islets of Langerhans include which type of cells?
A cells - glucagon; incr blood glucose levels
and B cells - insulin; dec blood glucose levels
what does the pineal gland secrete? how is this hormone released
melatonin
released in a diurnal rhythm linked to the dark/light cycle which helps to regulate the body’s biological clock (circadian rhythm)
what is SAD thought to be associated with?
an overproduction of melatonin
what are anabolic hormones required for? what are these hormones?
synthesis of molecules
include:
- gh
- insulin like growth factor
- insulin
- test/estrogen
what do catabolic hormones do? what are the hormones?
stimulate breakdown of molecules and the production of energy
include:
- cortisol
- glucagon
- adrenaline/epi
- cytokines
which hormones are the main ones that aid in the regulation of metabolism?
insulin and glucagon
what happens when the body is in a fed state?
blood glucose levels are high. this promotes the release of insulin which then:
- increases glucose uptake
- inc glucose metabolism
- energy storage as glycogen and fat
- inc the use of AA
what happens in a fasting state?
blood glucose levels are low. this increase glucagon release which causes:
- breakdown of glycogen
- formation of new glucose
- release of glucose from liver
- formation of ketones
what is the most effective way for the liver to convert glycogen into glucose? why?
glycogenolysis (breakdown of glucose in muscles)
cuz you get the most glucose
glycogenolysis is the most efficient pathway but at is the trade-off?
glycogen stores are limited - it depletes glycogen stores which eventually leads to bonking (hitting the wall)
what is bonking?
when you’ve used up all your muscle and essentially your liver glycogen
- blood sugars start falling (muscles aren’t able to have an easy energy source so they start to slow down)
