Brainscape's Knowledge GenomeTM

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


See full index

Phgy Final 210 > Final > Flashcards

Final Flashcards

1
Q

What are the four functions of the kidneys?

A

1) Regulation of water, inorganic ion balance, and acid-base balance
2) Removal of metabolic waste products from the blood and their excretion in the urine
3) Removal of foreign chemicals from the blood and their excretion in the urine
4) Production of hormones/enzymes

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

What are the three hormones/enzyme involved in the functions of kidney?

A

1) Erythropoietin: hormone that controls erythrocyte production
2) Renin: enzyme that controls the formation of angiotensin and influences blood pressure and sodium balance
3) 1,25-dihydroxyvitamin D: active vitamin that influences calcium balance

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

Where are the kidneys placed and how much do each of them weigh?

A

They are placed behind the peritoneum on either side of the vertebral column against the posterior abdominal wall. They each weigh 150 grams.

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

What does renal mean?

A

Pertaining to the kidneys.

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

What do the renal cortex and renal medulla produce?

A

They produce the urine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Does the venous system run side by side the arteriole system?

A

Yes but the flow goes the opposite side.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a Nephron?

A

Each kidney contains around 1 million subunits called nephrons. Each nephron consists if a Renal corpuscle (glomerulus(capillary loops) and bowman’s capsule) and a Tubule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the Renal Corpuscle?

A

the renal corpuscleis a filtration unit of the vertebrate nephrons which are functional units of the kidney.
It consists of a knot of capillaries (glomerulus) surrounded by a douple-walled capsule (Bowman’s capsule) that opens into a tubule.
Lined by epithelial cells, then the bowman’s capsule (visceral layer:podocytes) then Bowman’s space, then the parietal layer of the Bowman’s capsule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the Glomerulus?

A

The glomerulus, the filtering unit of the kidney, is a specialized bundle of capillaries that are uniquely situated between two resistance vessels.
These capillaries are each contained within the Bowman’s capsule and they are the only capillary beds in the body that are not surrounded by interstitial tissue.

Definition: entangled capillary loops surrounded by Bowman’s capsule.
Filters blood to make urine.

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

What are podocytes?

A

Finger like processes that are tightly surrounding the capillary wall and named after the feet structure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the Glomerular capillary wall (filtration barrier):

A

Blood, things move between the windows of the endothelial cells, through the basement membrane, through the filtration slip, into bowman’s space. Certain things can pass through but not everything (water can) but cell cannot, because size is an issue, you should not have blood or cells in urine and this is where it gets blocked. There are 3 layers that make up the filtration barrier in the glomerulus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does the capillary wall consist of?

A

1) Endothelial cells
2) Glomerular basement membrane
3) Visceral epithelial cells (podocytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the consecutive segments of the nephron:

A

1) Cortex:
Renal corpuscle:
- Glomerulus
- Bowman’s capsule
2) Medulla:
Henle’s loop
- Descending thin limb
- Ascending thin limb
- Thick ascending limb
3) Cortex:
Distal convoluted tubule
4) Medulla
- medullary collecting duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are three processes of urine formation?

A

1) Glomerular filtration
2) Tubular secretion
3) Tubular reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is glomerular filtration?

A

Urine formation begins with the filtration of plasma from the glomerular capillaries into Bowman’s space (glomerular filtration).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is Glomerular filtrate?

A

It is the fluid in Bowman’s space, it is cell-free and except for proteins, contains all the substances in plasma in virtually the same concentrations as in plasma. Water, electrolytes, waste such as urea can pass through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where does tubular secretion/tubular reabsorption take place?

A

As the glomerular filtrate passes through the tubules, its composition is altered by movements of substances.

Tubules –> Peritubular capillaries (reabsorption)
Pertibular capillaries –> Tubules (secretion)

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

Describe the formation of urine:

A

The first step is glomerular filtration into the bowmans space. The second step is secretion and then the 3rd step is reabsorption. The amount of urine excreted = filtered + secreted - reabsorbed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the process of urine formation (PAH) para-amino-hippurate

A

Something gets filtered at the glomerular capillary and then what is remaining goes through the peritubular capillary, as it goes through, what is left gets secreted into urine, and then excreted entirely in the urine. This happens rarely, but PAH means that everything delivered by the kidney to the blood is eliminated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe the process of urine formation with sodium and water.

A

This happens to most people, where some gets excreted and some gets reabosrbed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe the process of urine formation with glucose.

A

In a normal person glucose does not show up in the urine, and it all gets reabsorbed so this is a extreme example.

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

What is the rate of filtration, reabsorption, or secretion subject to?

A

It is subject to physiological control. When the body content of a substance goes above or below normal, homeostatic mechanisms can regulate the substance’s bodily balance by changing these rates.
e.g. If a normal person drinks a lot of water, reabosrption of water is decreased and excess water will be excreted in the urine.

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

What is filtered by glomerular filtration?

A
  • from the plasma, water and low-molecular weight substances move pass the barrier into the filtrate.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does not pass the barrier in glomerular filtration?

A

1) Cells
2) Proteins (albumin, globulins)
3) Protein-bound substances (1/2 of calcium ion, fatty acids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the forces involved in filtration? What favours filtration and what opposes filtration?

A

Favouring filtration:
Pgc = Glomerular capillary blood pressure

Opposing filtration:
Pbs = fluid pressure in Bowman’s space
Osmotic force due to protein in plasma (pi gc) = oncotic pressure

  • The pGC pusshes the pressure into the bowmans space, and the pigc and pbs pushes pressure back into glomerular capillary.
26
Q

What is the equation for net glomerular filtration pressure?

A

= Pgc - Pbc - Pi gc

= Glomerular capillary blood pressure - fluid pressure in bowman’s space - osmotic force due to protein in plasma

27
Q

What is the definition of GFR?

A

Glomerular filtration rate: the volume of fluid filtered from the glomeruli into Bowman’s space per unit time.

28
Q

What is GFR regulated by?

A

1) Net filtration pressure
2) Membrane permeability
3) Surface area available for filtration

29
Q

What is the normal GFR for a 70kg person?

A

180 L/day (125 ml/min)
N.B plasma volume of this person: 3.5 L
180/3.5 = 51
Plasma is filtered 51 times a day at the glomeruli!

30
Q

Describe the regulation of GFR: (decreased vs increased)

A

Decreased GFR:
Blood flow is coming from the left side, you pinch and constrict the AA, and then the blood pressure in the capillaries go down, and then the GFR goes down.

if you dilate the arteriole, it will go down. The pressure goes down. And this is the driving force, so if the pressure goes down, the GFR goes down.

Increased GFR:
If you constrict the EA, more blood comes in, and then more pressure and GFR is increased.
If you dilate the AA, then the pressure increases, and the GFR increases.

31
Q

What is the definition of the filtered load? What is the equation?

A

The total amount of freely filtered substance.
Filtered load = GFR x plasma concentration of the substance.
e.g.
Filtered load of glucose = 180 L/day x 1 g/L = 180 g/day

32
Q

What happens when the filtered load is greater than the amount excreted in the urine?
What happens when the filtered load is less than the amount excreted in the urine?

A

1) net reabsorption
2) net secretion

33
Q

Where does reabsorption take place?

A

It takes place from the tubular lumen to the peritubular capillary.
Tubular epithelial cells are connected to tight junctions.
There is pale blue intersitual fluid surrounding.

When it happens between cells it is paracellular and when it happens through cells it is transcellular.

34
Q

What happens if there is too much potassium?

A

This would be bad, it would stop the heart, you do not want too much.

35
Q

What are 4 important factors about tubular reabsorption?

A
  1. Filtered loads are enormous, generally greater than the amounts of substance of the substance in the body.
  2. Reabsorption of waste products is relatively incomplete (e.g. urea).
  3. Reabsorption of most useful plasma components (e.g. water, inorganic ions, and organic nutrients) is relatively complete.
  4. Reabsorption of some substances are not regulated (e.g. glucose, amino acids), while others are highly regulated (water, inorganic ions).
36
Q

Describe the two mechanisms for reabsorption:

A

1) Diffusion: often across the tight junctions connecting the tubular epithelial cells.
- always in paracellular group
- Urea (small/free filtered)
- Concentration of urea in tubule higher, then it diffuses along concentration gradient across tight junction to capillaries.
Example:
Urea is freely filtered at glomerulus.
In the proximal tubule, water reabsorption occurs.
Urea concentration in the tubular fluid becomes higher.
Urea diffuses into the interstitial fluid and peritubular capillaries.

2) Mediated transport: reabsorption by mediated transport occurs across tubular cells (transcellular epithelial transport)
- requires participation of transport proteins in the plasma membrane of tubular cells
- usually coupled to the reabsorption of sodium

37
Q

Describe mediated transport:

A

There is glucose cotransported (symporter) that brings sodium from the tubular lumen to the tubular epithelial cell. There are also amino acids. Then it goes into the pertibular capillary. And when Na goes in, ATPase goes from the peritubular capillary to the epithelial cell. GLucose and amino acids are released into the intersitial fluid.

38
Q

What is Transport maximum? (Tm) Provide example.

A

When the membrane transport proteins become saturated, the tubule can not reabsorb the substance anymore. This limit is called the transport maximum (Tm)

Example:
In people with uncontrolled diabetes mellitus, the plasma concentration of glucose can become very high and the filtered load of glucose exceeds the capacity of the tubules to reabsorb glucose (Tm is exceeded). As a result, glucose appears in the urine (glucosuria)

39
Q

Define tubular secretion.

A

Tubular secretion moves substances from peritubular capillaries into the tubular lumen. This is the opposite of reabsorption.
It is mediated by the two mechanisms, i.e. diffusion and transcellular mediated transport.

40
Q

What are the most important substances secreted by the tubules?

A

Hydrogen ion and potassium

41
Q

Tubular secretion is usually couple to ____

A

the reabsorption of sodium

42
Q

What needs to be in order to excrete waste products adequately?

A

-the GFR must be very large
- thus, the filtered volume of water and the filtered loads of all the non-waste plasma solutes are also very large

43
Q

What is the proximal tubule?

A

It reabsorbs most of this filtered water and solutes. It is also a major site of secretion for various solutes, except K+.

44
Q

What is Henle’s loop:

A

It reabsorbs relatively large quantities of the major ions (less water_

45
Q

What are the functions/characteristics of Distal convoluted tubule (DCT) and collecting duct (CD)?

A
  • The volume of water and masses of solutes reaching here are relatively small. Fine-tuning.
    -Determines the final amounts excreted in the urine by adjusting the rates of reabsorption, and in a few cases, secretion.
  • Most homeostatic controls are here.
46
Q

What is the concept of clearance? (definition and formula)

A

Clearance: the volume of plasma from which the substance is completely removed (“cleared’) by the kidneys per unit time.

Clearance of S (Cs) = Mass of S excreted per unit time/Plasma concentration of S (Ps)

Mass of S excreted per unit time = Urine concentration of S (Us) x Urine volume per unit time (V)
therefore:

Cs = UsV/Ps

47
Q

What is Inulin?

A

It is a polysaccharide that would be administered intravenously. It is freely filtered at glomerulus but is NOT reabsorbed, secreted, or metabolized by the tubule.

48
Q

What is the clearance of inulin (Cin) equal to?

A

It is equal to the volume of plasma originally filtered. (GFR)

49
Q

What is the most accurate marker of GFR?

A

Cin is.
Cin = GFR.

50
Q

Solve for GFR with the following information:
Concentration of inulin in plasma = 4mg/L
Urine volume = 2.4L
Inulin concentration in urine = 300 mg/L

A

Amount of inulin excreted in the urine:
= 2.4L/day x 300 mg/L
= 720 mg/day
Cin = 720 mg/day / 4mg/L = 180 L/day

therefore:
GFR= Cin= 180L/day

51
Q

What is creatinine?

A
  • Creatinine is a waste product produced by muscle.
  • It is filtered freely at glomerulus and is NOT reabsorbed.
  • It is secreted at the tubule but the amount is small. it is NOT metabolized by the tubule.
  • Thus, creatinine clearance is used as a clinical marker for GFR.
52
Q

What is the formula for creatinine clearance?

A

= UcrV/Pcr = GFR

53
Q

Find the creatine clearance with the following information:
Urine volume: 2L per day
Urine concentration of creatinine: 9.6 mmol/L
Plasma concentration= 0.3 mmol/L

A

Creatinine clearance= UcrV/Pcr = (9.6 x 2)/0.3 = 64 L/day
This person has lost around 2/3 of GFR

54
Q

If the clearance of a substance is greater than the GFR.

A

It is secreted at the tubule.

55
Q

If the clearance of a substance is less than the GFR.

A

It is reabsorbed at the tubule.

56
Q

Describe the total-body balance of sodium and water:

A

Sodium (Na) and water important components of the body fluids.
Total-body balance of na and water has to be maintained to sustain normal pressure and life.

57
Q

What are the values of the average daily water gain and loss in Adults?

A

Intake:

Liquids: 1200ml
Food: 1000ml
Metabolically produced: 350ml
Total: 2550ml

Output:
Insensible loss (skin and lungs): 500 ml
Sweat: 50 ml
Feces: 100ml
Urine: 1500 ml
Total: 2550 ml

58
Q

What is the value of the daily sodium chloride intake and loss?

A

Intake:
Food: 10.50g

Output:
Sweat: 0.25g
Feces: 0.25g
Urine: 10.00g
Total: 10.50g

59
Q

Are humans in a water and sodium balance? What is the range like?

A

Yes! water intake = water output. Sodium intake = sodium output. Depending on intake, water output can vary from 0.4 L/day to 25 L/day and sodium chloride output can vary from 0.05 g/day to 25 g/day. The dynamic range is huge.

60
Q

Describe the basic renal processes for sodium and water:

A
  • Both sodium and water and freely filtered but around 99% is reabsorbed (no secretion)
  • The majority of sodium and water reabsorption (around 2/3) occurs in the proximal tubule.
  • But the major hormonal control of reabsorption occurs on the DCT and CD. (Distal convoluted tubules and collecting duct)

1) Sodium reabsorption is an active process (ATP needs energy) occurring in all tubular segments (except descending thin limb of Henle’s loop)
2) Water reabsorption is by diffusion and is dependent upon sodium reabsorption (they diverge from each other and have a distinct difference here)

61
Q

Describe Active Sodium Reabsorption on the Basolaterial membrane and on the apical (luminal) membrane:

A

On the basolateral membrane:
Active Na+/K+ -ATPase pumps transport sodium out of the cells and keep the intracellular concentration of sodium low.

On the apical (luminal) membrane:
Sodium moves downhill from the tubular lumen into the epithelial cells. Each tubular segment has different mechanisms.
e.g. In the proximal tubule:
Na+-H+ antiporter (countrporter)
Na+- glucose cotransporter

In the CCD: diffusion via Na+ channel

Phgy Final 210 (1 decks)

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