Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Human Physiology > Renal > Flashcards

Renal Flashcards

1
Q

each nephron consists of ______________

A
  • > renal corpuscle (= initial filtering unit)
  • > tubule (= vessel for moving fluid (TF, not urine) through the nephron)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what makes up the filtration barrier that separates the glomerulus and Bowman’s capsule

A
  1. a single-celled endothelium layer (regulates molecular movement across the filtration barrier)
  2. a non-cellular proteinaceous layer (basement membrane of basal laminae)
  3. a single-celled epithelial lining called the podocytes that have numerous extensions/foot processes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

TF

A

tubular fluid

*NOT URINE*

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how does the filtration barrier filter fluid

A
  • > fluid filers first across the endothelial cells, then across the basement membrane and finally between the foot processes of the podocytes (where filtration slits are located)
  • > this process results in a cell and protein free fluid/filtrate entering Bowman’s capsule and the tubules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe the flow of blood through the renal corpuscle

A
  • > starts with the glomerulus which is supplied with blood via the afferent renal arterioles
  • > the glomerulus protrudes into a fuid filled capsule called Bowman’s capsule (these two structures are separated by a filtration membrane)
  • > as blood flows into the glomerulus around 20% filters into Bowman’s capsule with the remaining blood leaving the glomerulus via the efferent arterioles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe the tubular system

A
  • > renal tubules are hollow cylinders made of a single layer of epithelial cells resting on a basement membrane
  • > starts with the proximal tubule (= proximal convoluted tubule + proximal straight tubule), then the loop of Henle (=descending limb + ascending limb), then the distal convoluted tubule and finally the collecting duct system (= cortical collecting duct + medullary collecting duct)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

macula densa

A

specialized area of cells where the ascending limb merges into the distal convoluted tubules

  • > regulate blood pressure and the filtration rate of the glomerulus that detects sodium concentration of the fluid in the tubule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

juxtaglomerular cells

A

secretory cells that make up the wall of the affarent arteriole that secrete the enzyme renin often in response to signals from the macula densa

  • > renin is also part of the BV/BP maintenance pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

juxtaglomerular apparatus

A

the combination of the macula densa + juxtaglomerular cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

important regions in the kindey and which major structures for blood filtration does each region contain

A
  1. renal cortex (outer portion of the kidney)
    - > contains ALL the renal corpuscles; the loop of Henle pass from the cortex into the medulla; and the medullary collecting ducts pass through the medulla on their way to the renal pelvis
  2. renal medulla (inner portion of the kidney)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

2 general types of nephrons

A
  1. Juxtamedullary nephrons (15%)
  2. Cortical nephrons (85%)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

characteristics of juxtamedullary nephrons

A
  • > Henle’s loop pass deep into the medulla of these nephrons
  • > these are responsible for generating an osmotic gradient in the medulla and for water reabsorption (key to maintaining BV and BP)
  • > associated with these nephrons are specialized, long capillaries known as the vasa recta (help move Na+ and H2O from the TF back into the blood)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

characteristics of the cortical nephrons

A
  • > Henle’s loop do not pass as deeply into the medulla as the juxtamedullary nephrons - in fact, some cortical nephrons do not have a loop
  • > they are involved in reabsorption and secretion but not part of the regulation of the hypertonic medullary interstitium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

functions of the kidneys

A
  1. regulation of body fluid composition (4 processes)
  2. functions as an endocrine organ
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

the kidneys regulate body fluid composition through quantity and quality of urine by which four processes

A

1. Filtration

  • > formation of a protein and cell free fluid from blood

2. Secretion

  • > secretion/release of substances from the capillaries into fluid in the renal tubules OR release of substances from the tubular cells themselves into the lumen of the renal tubules

3. Reabsorption

  • > substances/fluids move from the renal tubules into the bloodstream (through the capillaries)

4. Excretions

  • > substances/fluids that leave the body via urine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The kindeys function as a endocrine organ by releasing which hormones?

A

1. erythropoietin

  • > stimulates production of RBC in the bone marrow

2. active vitamin D

  • > maintains healthy bone + immune system

3. manufacture and release of renin

  • > maintains BV/BP

4. release of prostaglandins

  • > important class of chemical messenger
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what percentage of the blood ejected from the LV with each heart beat goes to the kidneys/renal arteries

A

25%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

GFR

A

GLOMERULAR FILTRATION RATE

  • > volume of fluid filtered from glomeruli into Bowman’s space per unit time (24hr)
  • > not a fixed number but is regulated by a variety of neural and hormonal inputs that affect afferent and efferent renal arteriole BP and BV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

standard/average GFR in adults

A

180L/day, constant (125ml/min; this rate can change) such that the entire volume of plasma is filtered around 36 times/day

  • > GFR will change if you’re dehydrated or overhydrated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the several forces/pressures involved in filtration across the glomerulus

A

glomerular hydrostatic pressure (HPGC)

  • > the blood pressure in the glomerular capillaries, this favours filtration

hydrostatic pressure (HPCS)

  • > the fluid pressure in Bowman’s capsule, this opposes filtration

oncotic pressure (OPπGC)

  • > presence of proteins in the glomerular capillary plasma, thi opposes filtration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Net Glomerular filtration pressure

A

normally, the pressures favouring filtration are higher than those opposing filtration such that the net filtration pressure is positive which forces fluid across the filtration barrier into Bowman’s Capsule and then down the tubular system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

contriction of the afferent arterioles

A

constriction of the afferent arterioles will decrease the amount of blood entering into the glomerulus and therefore, decrease PGC (), decreasing the amount of fluid filtering across the filtration barrier and decreasing GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

constriction of efferent arteriole

A

constriction of the efferent arterioles will increase PGC, increase the amount of fluid filtering across the filtration barrier and increase GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Filtered load

A

the total amount of any non-protein substance filtered into Bowman’s space

FL = (GFR) x (plasma concentration of substance)

  • > can use to calculate renal function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

explain what happens when filtered load is <,> or = to the quantitiy of a substance excreted in urine

A
  1. If the quantity of S excreted in the urine < (less) than the filtered load, then reabsorption of S has occurred; filtration barrier has some blockages (can be caused by inflammation)
  2. If the quantity of S excreted in the urine > (greater) then the filtered load, than secretion of S has occurred; filtration barrier is leaky (bacterial infection)
  3. If the quantity of S excreted in the urine = the filtered load, then all of S was filtered with no secretion or reabsorption; normal renal function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Average values for certain plasma component that undergo filtration and reabsorption

A

EXTRA FACTS FOR TABLE

  • > 1% of filtered water that is excreted is required for the release of waste
  • > if 44% is reabsorbed than 56% is excreted
  • > urea is a byproduct of metabolisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

describe reabsorption by diffusion across the tubular cells

A
  • > dependant on [gradients] of H2O, Na, glucose and urea such that there is higher concentration of the substance in the ubular lumen than in the interstitium and plasma
  • > a variety of lipid-soluable organic substances are reabsorbed this way (i.e. urea)
28
Q

describe reabsorption by mediated transport

A
  • > substances using this route must first pass through the luminal membrane of the epithelial cells, and then cross the basolateral membrane
  • > substances don’t need to be actively transported across both the luminal and basolateral membranes (i.e. S could diffuse across luminal mem but use transport proteins to cross basolateral mem.)
  • >
29
Q

why do many of the substances reabsorbed using mediated transport hae a limit to how much can be moved per unit time

A

this limit is primarily due to the number of binding sites on the transporter proteins and the numbers of transporter proteins in the cell membranes.

i.e. ingesting very high concentrations of vitamin C will result in an increase in vitamin C in the plasma but will also result in an increase in vitamin C in the urine as tubular reabsorption of vitamin C has a limit

30
Q

secretion

A

- > secretion moves substances from the peritubular capillaries into the tubular lumen via diffusion or by mediated transport

  • > secretion can require the active pumping/transport of a substance from the blood into the epithelial cells, movement of the substance through the epithelial cells and then transport of the substance across the epithelial membrane into the tubular lumen
  • > secretion into the tubular fluid of substances from the interstitium is a faster means of moving substances out of the body than through the filtration pathway
  • > tubular cells are also capable of metabolism and can alter substances from the blood or tubular fluid and either secrete them in the altered form back into the tubular fluid or reabsorb them back into the blood
31
Q

most important substances moved by secretion

A

H+ and K+ but other substances such as choline and creatinine are also secreted

32
Q

primary kidney function

A
  • > maintaining correct water volumes and correct electrolyte concentrations along with filtering out unnecessary/toxic molecules
33
Q

What is the most important ion for water regulation in the kidney

A

Na+

34
Q

Characteristics of the proximal tubule

A
  • > reabsorption of 2/3 of the filtered water and Na+ occurs here
  • > water moves from the lumen of the proximal tubule, through the tubular cells that make up the tubular wall, through interstitial space and into the peritubular capillary through osmosis
  • > Na+ is brought from the tubular lumen into the tubular cells via co-transport with glucose (secondary active transport)
  • > Na+ is then moved into interstitial space via primary active transport (Na+-K+-ATPase) with K+ pumped into the cells
35
Q

Characteristics of the descending limb

A

water moves into the interstitium through simple diffusion, helped by the high interstitial osmolarity dues to the active pumping of sodium out of the tubular fluid and into the intersitium by the thick ascending limb

36
Q

characteristics of the Ascending limb

A
  • > part of the loop of Henle
  • > solute (Na+) is pumped out, therefore tubular fluid becomes diluted (low salt, high water)

- > this is the only site with active pumping Cl-

- > Mg and Ca are reabsorbed here through passive diffusion

37
Q

characteristics of the distal convoluted tubules

A
  • > this section of nephron is permeable to water
  • > Na is pumped out (with Cl- co-transport) and water follows the solute
  • > secretion of H and K occurs
38
Q

which hormone controls the movement of Na, K and H in the distal convoluted tubule

A

Aldosterone

39
Q

calcium reabsorption is controled by __________ in the distal convoluted tubules

A

PTH (parathyroid hormone)

  • > uses antiport system with sodium
40
Q

Characteristics of the collecting duct

A
  • > controlled reabsorption of water occurs here allowing for the formation of concentrated urine
  • > the antidiuretic hormone (ADH) signals an increase in aquaporins when increases water reabsorption is required
  • > each collecting duct receives tubular fluid from many nephrons
41
Q

renal pelvis

A

urine is collected here from collecting ducts of the nephrons and drains into the ureter

42
Q

Counter-Current Multiplier system

A
  • > the CCMS regulates the reabsorption of H2O and Na+ that has been pushed out of the descending/ascending limbs and into the interstitium
  • > kidneys are using salts/ions to increase interstitium osmolarity resulting in the movement of water out of the tubules and eventually into the bloodstream, maintaining plasma volumes and allowing for removal of wastes through urine without taking excess water with it
  • > salts(solutes) build up in the interstitial tissues, therefore, more water leaves the descending limb, the TF becomes more concetrated (higher osmolarity) and more Na+ is pumped out of the ascending limb
43
Q

explain the role of the vasa recta in the CCMS

A

the vasa recta helps the movement of water into the blood stream

  • > Na+ diffuses into the descending part of the vasa recta then diffuses out of the ascending part of the vasa recta into the interstitium which helps maintain high interstitial osmolarity
  • > water diffuses into the the vasa recta because of high oncotic pressure (presence of plasma proteins)
44
Q

urea

A

byproduct of protein metabolism

  • > 44% of filtered urea is reabsorbed and 56% is excreted
45
Q

which parts of the nephron is permeable to urea

A
  • > the ascending limb of the loop of Henle
  • > the end of the collecting duct
46
Q

role of urea in the CCMS

A
  • > urea transporters move large conc. of urea out of the collecting duct and into the interstitium
  • > some urea diffuses into the ascending limb of the loop of Henle
  • > some stays in the interstitium space where is helps to increase the osmolarity of the interstitium
  • > some also goes to the blood where is helps w/H2O reabsorption
47
Q

describe Na+ reabsorption

A

98% of Na+ is reabsorbed BEFORE the collecting ducts

  • > other 2% of Na+ is reabsorbed in the collecting ducts through the formation of Na+ transporters as a result of aldosterone stimulation (this depends of plasma [Na+])
48
Q

describe K+ regulation

A
  • > 90% of K+ is reabsorbed in the proximal tubules and the loop of Henle
  • > 10-20% is excreted into urine (dependant on plasma [K+])
  • > changes to K+ secretion/reabsorption is under the control of aldosterone and linked to Na+ movement
  • > increasing plasma [K+] results in the stimulation of the adrena cortex and increasing the levels of aldosteron are secreted
  • > increased plasma aldosterone levels results in an increased production of Na-K pumps and increased secretion of K by the collecting ducts
49
Q

descibe Ca regulation

A

- > 60% of plasma Ca is filterable (can cross filtration barrier), the other 40% is bound to plasma proteins (too big to cross barrier)

  • > 98-99% of the 60% is reabsorbed, mostly before the collecting ducts (can increase to 100% is Ca levels are low)
  • > parathyroid hormone and active vitamin D also play a role in regulating plasma concentration
50
Q

explain PTH and active vit. D’s role in the regulation of Ca [plasma]

A

- > decreased Ca levels stimulate parathyroid glands, increasing PTH secretion which has several effects of certain body systems

Renal Level

  • > inc. levels of PTH decreases phsosphate reabsorption but increasing Ca reabsorption (phosphate will bind with calcium, and we don’t want that)

Bone level

  • > inc. PTH results in increased bone resorption (breakdown) and increased plasma Ca levels by releasing Ca from bone

- > PTH causes the activation of Vit D which directly affects calcium absorption in the intestines, leading to inc. Ca levels

51
Q

Hydrogen is usually ______ in the body; explain

A

buffered

  • > combines with HCO3 to for CO2 and H2O
  • > binds to Hb
  • > GI fluids (i.e. HCl)
52
Q

how is H gained or lost in the respiratory system, the GI tract and the kidneys

A

Resp. System

hypoventilation = increased CO2 = inc. H (acidosis)

hyperventilation = decreased CO2 = decreased H (alkalosis)

GI tract

vomitting = decreases HCl = decreased H

diarrhea = decreased HCO3 = increased H

food = increased carbohydrate catabolism = increased H

Kidneys

decreased plasma H = inc. H reabsorption

inc. plasma H = decreased h reabsorption

53
Q

HPO4 is filtered by ________

A

the kidneys (HPO4 + H = H2PO4)

54
Q

how is ammonia (NH4) excreted in the urine

A
  • > glutamine from both the glomerular filtrate and the peritubular plasma is taken up mainly by the proximal tubular epithelial cells and metabolised, forming NH4 and HCO3
  • > the ammonia is secreted into the tubular fluid and excreted in urine while HCO3 is reabsorbed into the peritubular capilaries
55
Q

what is respiratory acidosis

A
  • > failure of lungs to eliminate CO2
  • > elevation of arterial CO2, elevation of arterial H
56
Q

what is metabolic acidosis

A
  • > excessive production of organic acids
  • > loss of HCO3; = increase in [H+]
57
Q

explain the body’s response to respiratory and/or metabolic acidosis

A
  1. lungs
    - > increased RR (their response time = seconds to minutes)
  2. Kidneys
    - > incresd HCO3 (response time = hours to days)

*lungs are immediately accivated but not very effective; kidneys start activating a while after by are quite effective

58
Q

explain pH regulation if patient is suffering from either form of acidosis

A
  1. reabsorption of filtered HCO3 + excretion of filtered H (HCO3 + H = CO2 +H2O)
  2. production of new HCO3 by the tubular cells that can be reabsorbed into plasma (or secreted into tubular fluid then reabsorbed into the plasma)
  3. other H+ buffer or reabsorption of filtered alternate buffers
59
Q

Respiratory ALkalosis

A
  • > CO2 eliminated too fast
  • > decrease in arterial CO2 decrease in arterial [H+]
60
Q

Metabolic ALKalosis

A
  • > loss of H+ through the GI system
61
Q

explain the body’s response to ALKalosis

A

lungs: decreased RR
kidney: excretion of HCO3
- > decreased excretion of H = reabsorbed filtered H
- > decreased glutamine metabolism (or stop)

62
Q

RAAS

A

Renin-Angiotensis Aldosterone system

  • > whole process starts with the release of a protein, renin, from the kidneys
  • > renin is released from the juxtaglomerular cells (JG cells) found in the juxtaglomerular apparatus (JGA) of the kidney
  • > angiotensinogen is secreted by the liver into the bloodstream
  • > renin (secreted into blood from the kidney) breaks angiotensinogen into angiotensin I
  • > angiotensin I continues in the bloodstream until the lungs where the angiotensin converting enzyme (ACE) cleaves it to form angiotensin II
  • > angiotensin II is a potent stimulator of aldosterone secretion (from the adrenal cortex)
  • > aldosterone is released into the bloodstream where it travels to the kidneys and increases Na+ reabsorption by the collecting ducts
63
Q

what regulates renin release is regulated by

A
  1. renal sympathetic response
  2. intrarenal baroreceptors
  3. macula densa
64
Q

renin secretion will be stimulated by _______

A
  • > decreasing ECF
  • > decreased BP
  • > increasing ß-adrenergic stimulation
  • > decreasing perfusion pressures
  • > decreasing plasma Na levels
65
Q

ADH

A

Antidiruetic Hormone

  • > decreased extracellular fluid/plasma volumes also stimulates the release of ADH from the posterior pituitary into bloodstream
  • > ADH travels to the kidneys and increases H2O permeability of the collecting ducts/ H2O reabsorption
66
Q

ANP

A

Atrial Natriuretic Peptide

  • > released by the myocardium
  • > acts on the kidneys by inhibiting Na reabsorption (therefore, increases Na excretion)

- > ANP release is stimulated by increased plasma volumes (noted by the stretch of the walls of the RA)

Human Physiology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions