Chapter 44/45: Osmoregulation, Excretion, & the Endocrine System Flashcards
osmoregulation
maintenance of concentration of solutes in body fluids
osmosis
movement of water from low solute to high solute concentration across a selectively permeable membrane
osmolarity
measure of osmotic pressure
hyperosmotic
net flow of water into cell
isoosmotic
no net water movement, osmotic balance
hypoosmotic
net flow of water out of cell
osmoconformer
body fluid becomes isoosmotic with environment
osmoregulatory
body fluid is regulated
stenohaline
organisms that tolerate a narrow range of salinity
euryhaline
organisms that can tolerate a wide range of salinity
marine fish osmoregulation
water lost by osmosis to environment; must drink lots of sea water
freshwater fish osmoregulation
water gained by osmosis from environment; excretion of water from kidneys
terrestrial animals osmoregulation
dehydration is the main concern, adaptions to retain water
ammonia (NH3)
nitrogen waste from protein/nucleic acid that is highly toxic but highly soluble; aquatic organism can let it diffuse from body surface
urea
many vertebrates convert NH3 to urea; lower toxicity, can be concentrated to conserve water; costly to produce
uric acid
reptiles and terrestrial invertebrates can convert NH3 to uric acid; lower toxicity, insoluble- precipitates as a solid; very costly to produce
urine
fluid waste produced through 4 step process: filtration, reabsorption, secretion, excretion
filtration
body fluid forced thru semi-permeable membrane; water and ions pass, proteins do not
reabsorption
water and ions are selectively taken back
secretion
wastes, etc, actively added to filtrate
excretion
remaining filtrate (urine) leaves the body
protonephridia
beating cilia draw body fluid into tubules of flatworms
metanephridia
tube connects coelom to outside of annelids
malpighian tubules
blind tubes connected to gut of insects
path of fluid from blood to the outside
blood serves each kidney by renal artery and renal vein, fluid leaves by ureter which drains to common urinary bladder, urinary bladder empties via urethra (controlled by sphincter muscles)
renal cortex
outer part of kidney
renal medulla
inner part of kidney
nephron
functional unit of the kidney
bowman’s capsule
beginning part of nephron
glomerulus
cluster of capillaries surrounding bowman’s capsule
path of filtrate within nephron
bowman’s capsule→proximal tubule→loop of henle→distal tubule→collecting duct→renal pelvic→ureter
afferent and efferent arterioles
from renal artery to and from glomerulus
peritubular capillaries
capillaries around tubules
vasa recta
circulatory system associated with loop of henle
proximal tubule reabsorption
first stage of concentration of wastes; active reabsorption of Na+, Cl-, K+
descending loop of henle reabsorption
permeable to water but not salts, further concentration of filtrate
ascending loop of henle reabsorption
reabsorption of NaCl; permeable to NaCl but not water
distal tubule reabsorption
regulates NaCl out, K+ in
collecting duct reabsorption
further concentrates filtrate
antidiuretic hormone (ADH)
hormone released in response to high blood osmolarity to increase reabsorption
renin-angiotensin-aldosterone system (RAAS)
hormone that maintains blood flow
hormones
basic system for regulating the body; involved in growth, development, homeostasis, etc.
endocrine system
hormones circulate in blood/hemolymph and activate target cells
paracrine and autocrine regulators
secrete molecules that act over short distances, local regulators
nervous system
network of neurons transmit signals to other cells (neurotransmitters)
pheromones
chemicals released outside the body to affect another organism (communication using hormones)
polypeptide hormones
proteins, water soluble
steroid hormones
lipids derived from cholesterol; lipid-soluble
amine hormones
synthesized from amino acids; solubility varies
water-soluble hormones
receptors in the plasma membrane that initiate signal transduction and response
lipid-soluble hormone
receptors in the nucleus or cytoplasm; interacts directly with DNA
hormone effects
circulate widely but only affect target cells with receptors that can bind that hormone
antagonistic pairs
various stimuli lead to secretions that pair in negative feedback loops, ie. insulin and glucagon
neuroendocrine pathway
coordination of endocrine and nervous systems
hypothalamus
endocrine gland in the brain, important for nervous/endocrine coordination
pituitary gland
2 glands fused together that receive neurosecretory signals from hypothalamus
posterior pituitary
stores two hormones from hypothalamus, ADH and oxytocin
anterior pituitary
makes several hormones that are released upon stimulation from hypothalamus, some tropic hormones
adrenal cortex and medulla
adrenal glands on kidneys
epinephrine and norepinephrine
released from adrenal medulla in response to stress; prepare body for short term excitement
mineralocorticoids and glucocorticoids
main types of steroids for long term stress response