Endo Lec 1 Flashcards
endocrinology (def.)
the study of hormones, their receptors, the signaling pathways they invoke, and the disease and condition associated with them
endocrinology involves the study of the (4)
- biosynthesis
- storage
- chemistry
- physiological function of hormones secreted from endocrine glands or other tissues
endocrine gland (def. + example)
lacks the duct system (ex. thyroid gland)
exocrine gland (def. + example)
has a duct system (ex. salivary gland)
gland that are both endocrine + exocrine
pancreas
communication differences in endocrine vs nervous system (4)
- secreted into blood system vs neurotransmitter released by diffusion
- travels over long distance vs acts locally (short distance)
- slow response vs fast action
- multiple target cells vs more target specific
hormone classification based on
structure (solubility in plasma)
structure of hormone dictates
site of receptor + mechanism of action
two types of hormones (general)
- water soluble
- lipid soluble
list of water soluble hormones (2)
- protein hormones
- catecholamines
list of lipid soluble hormones(3)
- steroids
- thyroid hormones
- eicosanoids
lipid soluble bound to … in…
carrier proteins in aqueous environment
3 types of hormones based on structure
- proteins
- lipids
- monoamines
3 types of protein hormones
- small peptides
- polypeptides
- glycoproteins
small peptides hormone examples (3)
- TRH (Thyrotropin-releasing hormone)
- oxytocin
- ADH (Antidiuretic hormone/vasopressin)
polypeptides hormones examples (3)
- insulin
- glucagon
- GH (growth hormone)
glycoproteins hormones examples (3)
- FSH (follicle stimulating hormone)
- LH (luteinizing hormone)
- TSH (thyroid-stimulating hormone)
2 types of lipids hormones (+ made from..)
- steroids (made from cholesterol)
2. eicosanoids (made from arachidonic acid)
steroids hormones examples (3)
- cortisol
- aldosterone
- “sex hormones”
eicosanoids hormones examples (2)
- prostaglandins
- leukotrienes
2 types of monoamines hormones (+ made from..)
- catecholamines (made from tyrosine)
2. thyroid hormones (made from tyrosine)
catecholamines hormones examples (3)
- dopamine
- noradrenaline
- adrenaline
thyroid hormones examples
- T3
- T4
protein hormones is…after synthesis
stored
steroid hormones is…and made
not stored and made on demand
3 factors affecting hormone activity
- amount of hormone freely available
- storage vs. synthesis
- metabolism of hormone (active/inactive form of hormones)
two types of receptors (+ hormone types)
- cell surface receptors (proteins+ catecholamines)
2. intracellular receptors that bind to steroid and thyroid hormones
type of cell surface receptors
- G-protein linked receptors
- Catalytic receptors
G-protein linked receptor- example (for adrenaline, glucagon)
- primary messenger
- secondary messenger
- protein kinase
- protein phosphorylation
- response of target cells
examples of secondary messengers (4)
- cAMP
- DAG
- IP3
- Ca2+
examples of protein kinases (3)
- PKA
- PKC
- Ca+/calmodulin dep. kinase
catalytic receptors - example (for insulin, GH)
- receptor has tyrosine kinase activity/receptor recruits tyrosine kinase activity after binding with hormone
- protein phosphorylation
- response of target cells
protein kinase + phosphatase are important in
cell signaling
protein kinase/phosphatase can
activate or deactivate proteins depending on the situation
substrate for kinase-mediated phosphorylation (3)
amino acids with -OH (serine, theonine, tyrosine)
receptors for steroid hormones of adrenal cortex (location)
mainly in cytoplasm
receptors for sex hormones (location)
mainly in nucleus
receptors for thyroid hormones (location)
bound to DNA in nucleus
receptors for lipid soluble hormones) end up
in the nucleus and act as transcription factors
speed of steroid + thyroid hormones
slow (hours to days)
speed of peptides + catecholamines hormones
-fast (minutes)
the ability of a cell to respond to a hormone depends upon
the presence of receptors for that hormone on or in the target cell
up-regulation (def.)
-increase in the number of receptors for hormone
down-regulation (def.)
-decrease in the number of receptors for hormone
permissive action of horomones
-the presence of one hormone is required in order for another hormone to exert its full effects on a target cell.
example of permissive actions of hormone
epinephrine + thyroid hormone= large amount of fatty acids released
permissive hormone (+ example)
the one that encourage the action, doesn’t cause action by itself
(ex. thyroid hormones (notes)+ glucocorticoids)
- upregulate receptors for other hormone on target cell
negative feedback … response
dampen
positive feedback … response
amplify
which feedback control is more common in body system
-negative
negative feedback (example)
PTH secretion and blood Ca++ (maintains homeostatic range)
positive feedback (example)
-cervical stretch and oxytocin secretion from posterior pituitary (amplify uterine contraction)
tropic hormone (def.)
increase secretion of hormone B from target gland
trophic hormone (def.)
increase secretion of hormone B and stimulate growth of the target gland
hyposecretion (def.)
secretion of too little hormone
hypersecretion (def.)
secretion of too much hormone
hyporesponsiveness (def. + example)
- reduced responsiveness of target cells
- ex. abnormal receptors (Laron Dwarfism)
hyperresponsiveness (def.)
-increased responsiveness of target cells
