Endocrinology- lecture 4 Flashcards
which 2 systems are intimately connected to maintain homeostasis
endocrine and nervous (neuroendocrine)
differences between nervous and endocrine
nervous–> each nerve cell terminates on a specific target ( wired)
- rapid and short lived effects
- can only stimulate muscles and glands across a synapse
endocrine–> wireless
- can access most tissues and cells ( not just muscle and glands)
- slower and longer lived
Neural specificity is due to ____ proximity
anatomic
endocrine glands are ______ glands, made of __________ white cells manufacture and secrete hormones
Ductless glands,
Glandular epithelium
endocrine vs exocrine
endocrine secrete hormones into the blood and have no ducts; whereas exocrine secrete products from ducts such as tear ducts and sweat glands
there are a few endocrine glands that secrete chemical messengers into the bloodstream that are made from?
neurosecretory tissue
Hypothalamus
master gland
- receives input and acts accordingly
- it controls the release of hormones in the anterior pituitary through releasing and inhibiting factors
what does TSH do?
what gland releases it?
Thyroid stimulating hormone tells the thyroid cells to produce thyroxine (T4) and T3
- Anterior pituitary gland
ACTH- adrenocorticotropic hormones ? from where?
stimulates cortisol secretion from adrenal cortex and comes from the AP gland
Growth hormone ? and from where?
anterior pituitary gland
FSH- follicle-stimulating hormone and LH- luteinizing hormone, from what gland?
act on gonads, growth of follicles, ovulation - from AP
Prolactin (PRL)
from AP gland and used form milk synthesis
MSH- melanocyte stimulating hormone is from what gland?
from AP gland
what hormones does the posterior pituitary release?
Vasopressin ( anti-diuretic) and Oxytocin ( milk let down)
what does the pineal gland produce?
Melatonin
what does thyroid gland produce?
T3 and T4 (thyroxine), calcitonin
Adrenal cortex gland produces?
- mineralocorticoids ex. aldosterone ( acts on kidneys to conserve salt, to retain water)
- corticosteroids such as cortisol
- androgens ex. DHEA (sex steroids)
Adrenal medulla gland produces?
epinephrine and norepinephrine- stress adaptation
Pancreas gland produces?
insulin, glucagon and somatostatin
Gonads gland produces?
testosterone and estrogen and progesterone
what is graves disease?
most common form of hyperthyroidism
- an immune system protein mimics TSH (autoimmune disease- meaning that the body thinks it is under attack by itself)
-
2 hydrophilic hormones are?
insulin and catecholamine ( adrenal hormones) epinephrine
which hormones are lipophilic?
thyroid hormones and steroids ( cortisol and sex hormones)
Tropic hormones are hormones that _________
target other endocrine glands and stimulate their growth and secretion of other hormones. for example ACTH ( which comes from the AP gland) and targets the adrenal cortex to release cortisol
Anabolic hormones stimulate?
anabolism ( to build) in target cells such as testosterone stimulating protein synthesis and the building of muscle
all hormones are transported in the blood however they are not ______ the same way
transported
Hydrophilic hormones are dissolved in the ____, lipophilic hormones are bound reversibly to _________,
plamsa, plasma proteins ( these hormones get release by the plasma proteins when they actively signal target cells)
difference between hydrophilic hormones and lipophilic hormones and receptors?
receptors on surface vs inside membrane
Hydrophilic hormone synthesis vs lipophilic synthesis?
hydro- preproxhormones are made on ribosomes on the ER, Golgi convert to pro hormones and then finally become hormones ( they are peptide chains bc proteins)- released by exocytosis
lipo- enzymatic steps in modifying cholesterol in a specific cell. Only cholesterol is stored, not the lipophilic hormones ( excreted or metabolized)
examples of non-steroids hormones
glycoprotein hormones,
protein hormones,
peptide hormones,
AA derivitive hormones- each derived from a single AA–> thyroid amine hormones which are made from tyrosine
how to make tyrosine?
from a single tyrosine AA, add 4 molecules of iodine!
How do hormones work?
they signal a cell by binding to the target cells specific receptor
3 combined hormone actions?
synergism, permissiveness and antagonism
permissiveness
when one hormone enables a second one to have its full effect
antagonism hormone
one produces the opposite effect o the other ( ex. parathyroid to increase blood Ca2+ and calcitonin to decrease)
how are hormones terminated?
they have a half life and are degraded into inactive metabolites in the liver and then excreted
Steroid hormones regulate cells by?
regulating the production of certain critical proteins that will illicit the cellular response
–> this is bc they go into the cytosol, bind to receptor molecule to form hormone-receptor complex and then more to the nucleus and activates a certain gene!
up-regulation means?
increased number of hormone receptors which increases the sensitivity to hormones
down-regulation
decreased number of hormone receptors
non steroid hormones usually trigger?
second messenger responses
control of hormonal secretion is usually part of a ______ loop?
negative feedback ( either by the changes produced by its target cell or by another glands target cell rresponse
infundibulum
stemlike stalk that connects pituitary to hypothalamus
anterior pituitary (adenohypophysis) targets?
bone/musculoskeletal (GH) adrenal cortex (ACTH) Thyroid ( TSH) Gonads-estes and ovaries (Gonadotrophic hormones) Mammary glands (prolactin-PRL)
posterior pituitary (also called the neurohypophysis) releases
oxytocin and vasopressin (ADH)
neuro-secretory cells have their bodies directly in the ____ and their axon terminals in the _______-.
hypothalamus
posterior pituitary
what are the five functional types of secretory cells that exist in the adenohypophysis and what do they secrete?
1) somatotrophs- GH (act on musculoskeletal )
2) Corticotrophs- ACTH and MSH ( act on adrenal cortex)
3) Thyrotrophs- TSH
4) Lactotrophs- PRL
5) Gonadotrophs- LH and FSH
Growth hormones ( what gland secretes them and what secretory cells secrete them) and what is their role?
secreted by somatotrophs in the adenohypophysis
- protein anabolism to promote growth in muscle
- lipid catabolism - which has a hyperglycaemic affect
hyperglycemic affect of GH
GH and insulin have opposite effects. GH affects metabolism in 3 ways
- promotes protein anabolism
- lipid mobilization and catabolization
- indirectly inhibits glucose metabolism by shifting energy use to lipid catabolism
- this indirectly increases blood glucose
Prolactin ( what gland secretes them and what secretory cells secrete them) and what is their role?
produced by lactotrophs in the anterior pituitary
- promotes development of milk
Tropic Hormones (what gland secretes them and what secretory cells secrete them) and what is their role?
tropic hormones are hormones that have a stimulating effect on other endocrine glands and tend to stimulate the synthesis ad secretion of the target hormone
What are the 4 tropic hormones produced by the adenohypophysis?
1) TSH
2) ACTH
3) FSH
4) LH
FSH role?
in females–> acts on ovary, secretion of estrogen
in males–> maintains spermatogenesis
LH roles?
in females- stimulates formation and activity of corpus luted of ovary
in males- stimulates cells in testes to develop and secrete testosterone
Cushing disease
hyper secretion of cortisol
hypo thyroid secretion
puffiness, slow heart rate, low bod temp, dry hair and skin
causes- iodine def, stress
type 2 diabetes
loss of tissue sensitivity to insulin
