homeostasis Flashcards
homeostasis path
imbalance
detected by receptor
info sent along afferent pathway to control center
info sent along infferent pathway to effector
return to homeostasis
homeostasis definition
maintenance of relatively constant internal environment in response to change in internal and external environment. In response to stimuli
self adjusting, involves feedback mechanism (positive, accentuates original stimuli, or negative, diminishes stimulus)
glucose homeostasis
pancreas secretes insulin if high blood glucose, liver/tissues/fat stores glucose
pancreas secretes glucagon is low blood glucose, liver secretes glucose
important to cellular respiration
endocrine systeme (gland for hormones) and urinary system regulate blood glucose
endocrine systeme
produces hormones to regulate the activity of other cells
endrocine glands and organse have exclusively endocrine functions, but also endocrine cells locates in tissues and organs part of other systems
exocrine glands
secrete products into ducts that empty themselves onto the blody surfave, space within organs or into a body cavity ex sebaceous glands
endocrine glands
lack ducts, hormones secreted diffuse dirrectly into the blood
target cells
hormones only affect a limited number of cells called target cells because they bear receptors for the hormone
2 classes of hormones
steroid/ other non-polar hydrophobic hormones that are lipid solible
pass through cells membrane and bind to intracellular receptors in cytosol or nucleus
change gene expression
Polypeptide/amine hydrophilic hormones that are water soluble
bind tp cell surface receptors in the membrane
triggers a cascade of reactions called signal transduction pathway, lead to intracellular (in cell) responses
urinary system
function:
collect water and filter body fluids
remove waste and return necessary fluids
eliminate excretory
composed of:
kidney (filters plasma, produces urine, conserves water, regulates pH, stimulates production of red blood cells, transforms vitamin D into active form)
ureter (transport urine from kidneys to bladder)
urinary bladder (stores urine)
urethra (transport urine outside of body)
kidney filtrates many times plasma volume to selectively process and remove wate (toxins, nitrogenous waste) while retaining and returning indispensable molecules (glucose,) to blood
in doing so, it also regulates the body fluids, ion, blood pressure and pH homeostasis
Brain Produces ADH from pituitary gland to stop you from peing and returning water to the body. Kidney absors high volume of water, urine is less and concentrated, or opposite
specific gravity
ration of mass of the liquid to the mass or an equal volume of distilled water at same temperature. more concetrated the urine it weighs more, has a higher specific gravity
urine
urea: largest components or urine appart from water is breakdown of amino acids
Uric acid: an end product of nucleic acid metabolism
creatine: metabolite of creatine phosphate (stores energy for the regeneration of ATP , is in skeletal muscle tissue)
no glucose should be present in urine under homeostatic conditions, if present (called glycosuria) it indicates a high level of blood glucose (can be diabetes)
diabetes mellitus
insulin production by pancreas or insulin recepetors inadequate
pH
acidic: metabolic or systemic acidosis
basic: metabolic alkalosis
can cause protein denaturation
respiratory system regulates blood pH by increasing or decreasing respiratory rate
urinary systeme regulates buffering molecules (H+, HCO3-, etc) to modulate pH ( first line of defense in blood in resisting pH change)
CO2 on pH
CO2 produce of cellular respiration, not O2 usage
CO2 has impact on pH (combines with water in red blood cells and produces HCO3- and H+), needs to be illiminated (done by respiratory, cardiovasular and muscular systems)
Increase in ATP synthesis leads to more CO2 leads to more H+ leads to a decrease in pH) , and alternatively
Medulla detecs change in pH of cerebrospinal fluid
rythm of bretahing mainly governed by concentration of CO2 through detection using specific receptors, so respiratory system adjusts breathing (more breathing is CO2 level decreased)
Which brain region is responsible for maintaining homeostasis in many body systems?
Hypothalamus
