Chapter 48: Regulating the Internal Environment Flashcards by Rachel Jones

What is osmoregulation?

regulation of water and ion balance

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What makes up the ECF?

ISF and blood plasma

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What is osmolarity?

The total solute concentration of a solution

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What is the osmolarity of body fluids in humans and other mammals?

about 300 mOsm/L

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What occurs at the proximal vs distal end of excretory tubules?

proximal where fluid goes in and distal end is where fluid flows to the exterior of the organism

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What are the 4 steps in tublue function?

filtration, tubular reabsorption, tubular secretion, and excretion

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Key points about ammonia?

NH3, 1N
soluble in water, highly toxic
must be excreted in dilute solutions—high water loss
fishes

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Key points about urea?

2N
all mammals, most amphibians, some reptiles, some marine fishes, and some terrestrial invertebrates
nontoxic
minimal water needed

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Key points about uric acid?

4N
birds and reptiles
nontoxic
paste
extremely low water loss

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What common osmoconformers? typically osmolarity?

marine invertebrates, about 1000 mOsm/L

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What common osmoregulators?

all freshwater invertebrates

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What are the 3 types of tubules and where are they found?

Protonephridia- flatworms and larval mollusks
METANEPHRIDIA- ANNELIDS AND MOST ADULT MOLLUSKS
MALPIGHIAN TUBULES- INSECTS AND OTHER ARTHROPODS

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What is a flame cell? located?

located in protonephridia, contain cilia that move fluid through the tubule

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What are peritubular capillaries?

reabsorb important molecules and ions from the filtrate

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Is the collecting duct part of the nephron?

nope

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What are the 4 major regions of the nephron?

renal corpuscle, proximal convoluted tubule, loop of henle, and distal convoluted tubule

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Which has a bigger diameter the afferent arteriole or efferent arteriole? purpose?

afferent arteriole to maintain a high level of glomerular capillary pressure

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What is the structure of the Bowman’s capsule and glomerulus?

glomerulus is a ball of arterial capillaries, Bowman’s capsule houses the glomerulus and is where filtration occurs

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What happens in the proximal convoluted tube?

bicarb, NaCL, H2), nutrients, K pumped out for reabsorption

H+ and NH3 pumped in for excretion

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What happens in the descending loop of henle?

H2O moves out and NaCl moves in. osmolarity increases

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What is the purpose of the distal tubule?

allows for more water reabsorption, allows for adaption to the environment

Are the collecting ducts permeable to water? salt?

yes to water, no to salt ions

What is the difference between the macula densa and juxtaglomerular cells? what do these two form?

macula densa focus on what is leaving
juxtaglomerular cells focus on what is entering

form juxtaglomerular complex

What is the raas regulatory mechanism?

renin-angiotensin-aldosterone system

regulates Na, fixes levels if juxtaglomerular complex fails to do so

How do ACE inhibitors work?

prevents the secretion of angiotensin II which lowers blood pressure. Prevents the secretion of aldosterone from the adrenal glands which would increase blood volume

What are the 3 effects of angiotensin II?

1) raises bp via constricting arterioles 2) stimulates synthesis/secretion of aldosterone 3) stimulates thirst

What are the 3 effects of atrial natriuretic factor (ANF)?

1) inhibits renin release 2) dilates afferent arterioles 3) inhibits aldosterone release

Where are ADH-secreting neurons located?

hypothalamus

What does ADH do?

increases water reabsorption in collecting ducts by promoting the insertion of more aquaporins into the epithelial membranes doesn't work in distal convoluted tubules

What are marine teleosts?

fishies that continually lose water to their environment by osmosis and must replace it by continual drinking they try and dilute the ocean don't pee a lot of water out

How do sharks and rays maintain osmolarity as conformers?

retaining high levels of urea and trimethylamine oxide (TMAO) in body fluids they don't have to drink water

What occurs in freshwater fish?

they are hyperosmotic to their environment, so the water moves into the fish---don't have to drink water pee a lot of water out

In terrestrial amphibians what is the function of the bladder?

in addition to storage of urine, reabsorption of salt occurs also

How do birds and reptiles deal with salt/water concentrations?

they have salt glands that take on excess salt which are excreted in a concentrated salt solution

How do terrestrial mammals conserve water? (3)

1) loop of henle 2) lungs deep in body to reduce evaporation 3) covered in keratinizes skin to reduce evaporation

What are the 4 ways to lose or gain heat?

conduction, convection, radiation, and evaporation

Difference between conduction and convection?

convection is indirect contact, conduction is direction contact

What is an ectotherms?

cold-blooded animals that don't produce their own heat source. move around their environment to obtain heat

What is an endotherms?

warm blooded, have set points

How does cold weather effect ectotherms and endotherms differently?

ectotherms metabolism doesn't change much but daily activities are reduced endotherms metabolic rate rise at low temps and maintain daily activities

How can some ectotherms react to cold temps?

add an "antifreeze" molecule like glycerol to their body fluids

What does the core temperature refer to?

abdominal and thoracic organs, CNS, and skeletal muscles

Where are thermoreceptors found?

skin (integument), spinal cord, and hypothalamus

What is the purpose of brown adipose tissue?

can produce heat rapidly

How do animals without sweat glands sweat?

via panting

What are keratin fibers?

a surface layer of dead epidermal cells that forms a tough layer resistant to water loss

What does the dermis contain?

sweat glands, hair follicles, and thermoreceptors

What does the hypodermis contain?

larger blood vessels and fatty tissue/blubber

What is torpor?

reduction in metabolic, nervous, and physical activity induce this sleep like state----falling iguanas hibernation- extend torpor

What is estivation?

too hot/water scares--ex) burying in mud to cool down

How does countercurrent head exchange occur in the blood?

warm blood from artery warms blood in vein returning to the heart via conduction

How does countercurrent head exchange occur in the nose?

when exhaling some water condense on the nasal fold. inhalation air evaporates some air on nasal fold which cools the folds for the next outgoing breath.