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BIO 103 > Ch. 44 - Osmoregulation and Excretion > Flashcards

Ch. 44 - Osmoregulation and Excretion Flashcards

big ideas: kidney A&P, osmoconformers/regulators, kidney gradients, and how hormones affect the kidneys

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1
Q

what is osmoregulation?

A

the regulation of the solutes of body fluids [maintaining salt / water concentration]

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2
Q

what is excretion?

A

the removal of metabolic wastes from body fluids

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3
Q

what is osmolarity?

A

the measure of the solute concentration in a volume of solvent

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4
Q

what is an osmoconformer?

A

an organism in which the osmolarity varies with its environment

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5
Q

what traits are common of osmoconformers?

A

-live in places with constant osmolarity
-spend little energy maintaining ion gradients

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6
Q

what are osmoregulators?

A

organisms that maintain their solute concentration around a set point

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7
Q

what osmoregulation happens in a hypoosmotic environment?

A

-water diffuses in, so salts must be pumped in

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8
Q

what osmoregulation occurs in a hyperosmotic environment?

A

-water diffuses out, so salts must be pumped out
-must spend energy to maintain constant osmolarity

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9
Q

how does shark osmoregulation differ from marine fish?

A

shark cells have a salt concentration typical to fish, but they concentrate urea = slightly hyperosmotic = water moves into sharks

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10
Q

what osmoregulatory strategies do marine animals use?

A

-water is constantly moving out & salts in
-fish need to conserve water & remove salts
-active transport of Cl- out of gills, Na follows, urine is very concentrated

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11
Q

what osmoregulatory strategies do freshwater animals use?

A

-water is constantly moving in & salts out
-fish need to conserve salts & remove water
-pump Cl- into gills, Na+ follows, urine is very dilute

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12
Q

what osmoregulatory strategies do terrestrial animals use?

A

body coverings [skin/fur]
kidneys to conserve water
-behavior [avoiding heat]

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13
Q

what are the three main types of nitrogenous waste?

A

ammonia/NH3, urea, and uric acid

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14
Q

how is ammonia eliminated from fresh water fish?

A

ammonia is not converted into any other compound, it is diluted with water and excreted as is

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15
Q

how is ammonia removed from mammals and amphibians?

A

ammonia is converted to urea, which is then eliminated through excretion

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16
Q

how is ammonia eliminated in reptiles and birds?

A

ammonia is converted to uric acid, which is then eliminated in waste

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17
Q

what are the three portions of the kidney?

A

the outer cortex, inner medulla, and renal pelvis

18
Q

what kidney component is found in the outer cortex?

A

the glomerulus of the nephron

19
Q

what kidney components are found in the inner medulla?

A

-the nephron loop and collecting ducts which form the renal pyramids

20
Q

what is the nephron?

A

the smallest functional unit of a kidney, which produces urine

21
Q

what are the five main structures found in the nephron?

A
  1. glomerulus
  2. proximal convoluted tubule
  3. nephron loop
  4. distal convoluted tubule
  5. collecting duct
22
Q

what is the function of the glomerulus?

A

-to collect fluid filtered from the blood
-also begins formation of the filtrate [what becomes urine]

23
Q

what is the function of the proximal convoluted tubule?

A

-where reabsorption of nutrients and water begins
-some wastes and things not filtered from the glomerulus are secreted here

24
Q

what is the function of the nephron loop?

A

to establish a concentration gradient and further remove water and ions from the nephron

25
Q

what is the function of the distal collecting loop?

A

-to be the “last chance” to reabsorb water/nutrients/ions as well as secrete waste products

26
Q

what are the four main steps of urine formation?

A
  1. filtration of blood plasma
  2. reabsorption of filtrate
  3. secretion of wastes
  4. concentration of the urine
27
Q

where does filtration of blood plasma occur in the kidneys?

A

within the glomerulus

28
Q

where does filtrate reabsorption occur in the kidneys?

A

within the proximal & distal convoluted tubules

29
Q

where does waste secretion occur in the kidneys?

A

within the proximal & distal convoluted tubules

30
Q

where does urine concentration occur in the kidneys?

A

within the DCT and collecting duct, due to the concentration gradient established by the nephron loop

31
Q

what are cortical nephrons?

A

-nephrons that do not create an osmotic gradient in the medulla (85%)

32
Q

what is the purpose of antidiuretic hormone?

A

to reduce blood osmolarity and increase the concentration of urine [retaining water in the body]

33
Q

what is the purpose of angiotensin II?

A

to constrict the afferent arteriole in the glomerulus, increasing blood pressure and stimulating aldosterone + ADH secretion

34
Q

what is the purpose of aldosterone?

A

-inserts Na/K pumps into collecting duct, increasing Na+ reabsorption from CD into blood, causing water to leave as well
-blood pressure is increased, blood osmolarity stays the same

35
Q

what is the purpose of renin?

A

to activate angiotensinogen to angiotensinogen I, which gets converted to angiotensinogen II by ACE [from lungs]

36
Q

what is the renin-angiotensin-aldosterone system / RAAS?

A

a system of three hormones that work to control long term regulation of blood pressure

37
Q

what is the purpose of atrial natriuretic peptide / ANP?

A

to block renin & aldosterone secretion, lowering blood pressure

38
Q

what stimulus causes release of antidiuretic hormone?

A

dehydration = increased blood osmolarity

39
Q

what stimulus causes release of renin?

A

low blood pressure - which then activates the RAAS system

40
Q

what stimulus causes release of atrial natriuretic peptide?

A

high blood pressure due to exercise [ANP causes long term blood pressure lowering which is why exercise combats high BP]

41
Q

how are nitrogenous wastes such as ammonia formed?

A

they are formed from the break down of proteins into amino acids

BIO 103 (24 decks)

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