Principles of Homeostasis Flashcards
what is homeostasis?
the relative constancy of the body and the maintenance of constant conditions in the body’s environment
it is how an organism regulates it’s internal environment to maintain stability
what is compensation?
the return to homeostasis after being challenged (something deviating from the norm)
what is decompensation?
the failure to compensate, adapt, heal (can’t bring it back to stability)
efferent?
travelling outwards
what nervous system does homeostasis involve?
autonomic nervous system
what does the autonomic nervous system innervate?
it innervates smooth muscle, cardiac muscle and glands
what are two nerve fibres connected by?
a synapse
positive feedback example - during labour:
oxytocin during parturition triggering contractions - oxytocin triggers more muscle contractions which triggers more oxytocin to be release etc.
positive feedback example - during protein digestion:
AAs sensed, CCK produced, proteins broken down to produce more AAs so more CCK then produced
examples of negative feedback:
temp control
water balance
pH of the blood (acid-base balance)
what does the Juxta-glomerular apparatus stimulate?
the RAAS pathway
what does the RAAS pathway result in?
sodium retention
parathyroid gland?
releases parathyroid gland hormone
what does the release of the parathyroid gland hormone result in?
increases calcium ion uptake in intestines and in kidneys and stimulates Ca2+ release from bones
two ways a cell can die?
necrosis and apoptosis
apoptosis?
controlled cell death, in control of what is happening, cellular suicide, DNA/proteins damaged
steps of apoptosis?
normal cell –> condensation –> fragmentation –> apoptic bodies
stages of necrosis?
normal cell, swelling, irreversible swelling and then disintegration
morphology of necrosis?
random
morphology of apoptosis?
typical
what cells are found in the crypts of the gut?
stem cells
what are the stem cells found in the crypts of the gut producing?
intestinal epithelium - crypt base columnar cells
coeliac disease destroys?
crypt base columnar cells, the folds flatten out and it is harder for the body to absorb nutrients
misfolded protein results in?
it forms an enzyme which causes more proteins to misfold just like it
