homeostasis Flashcards
homiosis - similar, stasis - standing still
homeostasis name
internal and external balance for the body to maintain with homeostasis
dynamic equilibrium
state of the body where internal physical chemical conditions are tolerable range for biological processes
homeostasis
decrease in blood pH, <7.35
acidosis
increase in blood pH, >7.45
alkalosis
decrease in blood sugar
hypoglycemia
increase in blood sugar
hyperglycemia
extreme cold, dropping body temperature
hypothermia
fever, increase in body temp
hyperthermia
overactive thyroid
hyperthyroidism
underactive thyroid
hypothyroidism
receptor (monitor), control centre/CNS (integrator), effector (regulator)
homeostatic feedback loops
sensors/receptors that receive stimulus from environment and send a message
receptor (monitor)
control centre that relays the message from receptor to appropriate location in body for a response to occur
control centre/CNS (integrator)
effector responds to message, leading in body change that restores homeostasis, e.g. glands, muscles, blood vessels
effector (regulator)
receptor is thermostat sensor, stimulus is air temperature, control centre is thermostat, furnace is effector, desired temp is response
thermostat example
maintain normal body constants, sensory receptor, stimulus, control centre, effector reverses change to equilibrium
negative feedback loops
messages traveling from receptor to control centre along these
afferent nerves
messages travel from the control centre to effector along these
efferent nerves
don’t maintain homeostasis and used only when there is definite endpoint, intensify changes away from equilibrium
positive feedback loops impact
to filter blood in order to remove waste fluid from body through urine
function of kidneys
functional unit of kidneys, tubules, millions of them in each kidney
nephrons
filtration, reabsorption, secretion, extretion
functions of the nephron
begins in bowman’s capsule, urine formation begins by forming an ultrafiltrate that contains water, ions, glucose, amino acids, nitrogenous waste molecules, vitamins and minerals
filtration
first part of the nephron
bowmans capsule
blood vessels
glomerulus
filtrate enters the proximal convoluted tubule where nutrients are reabsorbed by active transport, water leaves filtrate by osmosis through aquaporins, some secretion happens in proximal convoluted tubule when H+ is actively secreted to maintain blood pH
reabsorption 1
filtrate moves into descending loop where additional water is reabsorbed, causing molecules + ions to become more concentrated, then ascending loop where high concentrations move out by passive transport and ions out of the tubule by active transport near the top, then enters distal convoluted loop where ions are reabsorbed, some secretion occurs in distal convoluted tubule where ions are secreted by active transport
reabsorption 2
impermeable to water
ascending loop of henle
filtrate enters collecting duct and H+ is secreted to maintain pH balance, secretion also occurs in proximal and distal convoluted tubes, reabsorption also occurs in the collecting duct
secretion
