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BIO 216 Test 3 > Osmoregulation > Flashcards

Osmoregulation Flashcards

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Biology 101 flashcards
1
Q

Define osmosis

A

-passive transport of water across a selectively permeable membrane in response to solute concentration gradients, pressure gradients

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2
Q

Define solute concentration

A

-is measured as osmolarity in millimoles per liter of solution (mOsm/L)

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3
Q

Define osmoregulation

A

-maintaining osmolarity of body fluids

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4
Q

Define osmotic pressure

A

-the minimum pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane

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5
Q

Define osmoregulators

A

-keep the osmolarity of body fluids different from that of the environment

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6
Q

Define osmoconformers

A

-Allow the osmolarity of their body fluids to match that of the environment

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7
Q

Molecules and ions are… from the body to keep cellular and extracellular fluids isosmotic

A

Removed

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8
Q

In most animals, extracellular fluids are … through… formed from …… and released to the exterior of the animal as …..

A

-filtered; tubules; transport epithelium(layer of cells with transport proteins in their membrane); urine

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9
Q

Define filtration

A

-small molecules and ions from body fluids or blood non selectively, pass through narrow spaces between cells into the tubule

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10
Q

Define reabsorption

A

-nutrient molecules, some ions and conserved water are returned to the body fluids or blood by transport epithelium

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11
Q

Define secretion

A

-Excess ions and toxic breakdown products are transported selectively from the bodily fluids or blood into the tubule

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12
Q

Define release

A

-urine(nitrogenous wastes, some ions, toxic breakdown products, excreted water) is released into the environment

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13
Q

What are things that generally get reabsorbed?

A

-glucose, amino acids, ions:Na+,K+,Cl-, water, HCO3-

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14
Q

What ions generally get secreted and why?

A

-H+, and K+
-it’s important for maintaining ion and pH balance

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15
Q

What gets excreted?

A

-substances that are unneeded or are in excess
-Wastes such as nitrogen compounds, NH3 (ammonia)

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16
Q

Define secretion

A

-the discharge of wastes from the body fluid into the filtrate
-selective process in which specific small molecules and ions are transported from the blood into the excretory tubules

17
Q

Define excretion

A

-elimination of substances from the body
-disposal of nitrogen containing waste products of metabolism

18
Q

What are the three main nitrogenous waste products

A

-ammonia, urea, uric acid

19
Q

In mammals, urine is …. To body fluids

A

-hyperosmotic(conserves water)

20
Q

Define nephron

A

-a structure in the kidney; specialized tubule involved in osmoregulation/excretion

21
Q

Describe filtration

A

At the proximal end, the nephron forms a cuplike structure= Bowman’s capsule which is around a ball of capillaries(glomerus).
Water, amino acids,ions, glucose, and nitrogenous waster molecules are forced from the glomerus into Bowman’s capsule. The fluid in the Bowman’s capsule is called filtrate.
Filtrate travels through the nephron(where reabsorption and secretion occur) and drains into the collecting ducts and renal pelvis–>ureter–>urinary bladder–>urethra

22
Q

afferent arterioles

A

deliver blood to the glomerulus

23
Q

efferent arterioles

A

receives blood from the glomerulus; has smaller diameter—> blood “backs up” (dam) in glomerulus, keeping pressure high

24
Q

What is the function of the collecting duct?

A

To concentrate urine

25
Q

In the distal convoluted tubule, what is reabsorbed and what is secreted

A

Na+, Cl-, H2O, and HCO3- are reabsorbed
K+ and H+ are secreted

26
Q

Describe what occurs in the ascending loop of henle

A

Na+ and Cl- are reabsorbed(move from tubule to interstitial fluid)
As the tubule ascends, Na+ and Cl- are actively transported out of the tubule fluid in tubule has a lower osmolarity as tubule ascends toward cortex
Ascending limb is impermeable to water(bc of a lack of aquaporin)

27
Q

Describe the descending loop of henle

A

Tubule passes through increasingly higher regions of solute concentrations of interstitial fluid in the medulla
Thus water moves out from tubule
This, then concentrates the filtrate in the tubule

28
Q

Describe the overall functions of Loop of Henle

A

Sets up a gradient of solutes in interstitial fluid
Very high solute concentration towards pelvis of kidney
Descending segment is for water reabsoprtion by osmosis
Ascending segment is for Na+ and Cl-reabsoprtion

29
Q

Describe the main functions of the proximal tubule

A

Main function: reabsorption of water, ions, and nutrients back into the interstitial fluid

30
Q

What does the proximal tubule secrete? and what does it reabsorb?

A

Secretes H= into the filtrate
Reabsorbs Na+, Cl-, and K+ along with water, HCO3- and nutrients

31
Q

To conserve nutrients and water, to balance salts, concentrate wastes for excretion, kidney function controls…

A

Control osmolarity: mainly by adjusting water loss
Control total fluid volume: mainly be adjusting Na+ loss
Control pH: Mainly by adjusting bicarbonate loss or gain
involved with blood pressure and blood volume control
Make renin

32
Q

Water reabsorption in the kidney can be regulated by

A

ADH

33
Q

ADH is released from

A

pituitary when osmoreceptors(in the hypothalamus) detect an increase in osmolarity of body fluids

34
Q

Angiotensin also stimulates secretion of…

A

ADH

35
Q

Function of ADH

A

increases water reabsorption and stimulates thirst

36
Q

Summarize what happens when there is thirst

A

Too little water in the blood, detected by the hypothalamus
More ADH is produced by the pituitary gland
More water reabsorbed by the kidneys caused by ADH
Blood becomes less concentrated
Negative feedback: The hypothalamus detects changes in blood concentration. The pituitary produces less ADH. Blood returns to correct osmotic concentration

37
Q

ANP function

A

A protein hormone that inhibits the effects of renin (and leads to blood pressure decrease)
ANP promotes natriuresis (loss of sodium

38
Q

Give an overview ANP functions

A

ANP promotes natriuresis
Atrial myocytes synthesize, store, and release ANP in response to stretch (indicated by high blood volume)

39
Q
A

BIO 216 Test 3 (5 decks)

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