Brainscape's Knowledge GenomeTM

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


See full index

Physiology Block 3 > 1 - Renal > Flashcards

1 - Renal Flashcards

1
Q

What are the functions of the kidney?

A
  1. Excretion of metabolic waste
  2. Regulation of water and electrolytes
  3. Regulation of body fluid osmolality and electrolyte concentrations
  4. Regulation of art BP
  5. Reg of acid-base balance
  6. Secretion, metabolism, and excretion of hormones
  7. Gluconeogenesis

Essentially control volume and composition of body fluids.

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

How is fluid lost? What is the way that is controlled?

A

Through the skin, lungs, sweat and feces.

Urinary excretion of water tightly controlled.

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

How much of our body weight is composed of water? What is the average man we consider for our calculations and how much of his body volume is water?

A

Typically 50-70%. Greater in lean individuals.

Avg 70 kg man - would have ~42 L of total body water (70 x .6)

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

How is the water in the body distributed?

How does this divide out for the 70 kg man?

A

Intracellular fluid (ICF) - 2/3 of total body water (40% of body weight)

Extracellular fluid (ECF) - 1/3 total body water (20% weight)

70kg man would have ~28 liters (42 x 2/3) in the ICF and ~14 L in the ECF.

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

What is extracellular fluid composed of?

How does this pertain to the 70kg man?

A

Interstitial fluid: ~3/4 of ECF

Plasma (non-cellular, liquid): ~1/4 of ECF

70kg man: ~11 L in the interstitium and ~3 of plasma.

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

How do you calculate blood volume? What is the blood volume of a normal individual?

A

Plasma volume / (1-Hct)

3/ (1-.40) = ~5 L

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

What separates the ECF and ICF?

What separates the plasma and interstitial fluid?

A

ECF and ICF: cell membrane

Plasma and interstitial fluid: capillary membrane

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

How does the composition of plasma differ from that of interstitial fluid? Why isthis?

A

They are approx the same except that plasma has a higher concentration of protein.

This is because the capillary wall is highly permeable to water, electrolytes, and other small molecules but not to proteins.

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

Explain the differences between the ECF and ICF?

A

Cell membrane is highly permeable to water, but not most electrolytes.

ECF is relatively high in Na+, Cl-, and HCO3-.

ICF is relatively high in K+, PO43-, organic anions, and protein.

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

How do you measure body fluid volumes using the indicator dilution method?

A

Indicator Mass A = Volume A x Concentration A

Indicator mass A = Indicator mass B

Indicator mass B = Vol B x concentration B

Volume B = indicator mass B/Concentration B

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

How do you calculate body fluid volume?

A

Volume = quantity remaining in body (amount) / Concentration (amt/vol)

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

A 70 kg man is injected with 4x10^6 cpm H2O, 15 minutes later the sample is measured at 100 cpm/ml. Calculate the total body water?

A

total body water = Q/C = 4x10^6 cpm / 100 cpm/ml = 40,000 ml = 40 L

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

What governs the distribution of water between the ECF and ICF?

A

Osmotic forces, the barrier being the cell membrane.

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

Define osmolarity

A

Function of the total number of proteins in solution, independent of mass, charge, or chemical composition.

Concentration of osmotically active particles in the total solution.

Expressed in terms of milliosmoles (mOsm)/L

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

For substances that do not dissociate into smaller ones, how many osmoles are in one mole? What does this mean in terms of miliosmoles?

A

1mmol = 1milliosmole

It’s a one to one ratio when they do not dissociate.

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

What is the ratio of mmoles to miliosmoles for NaCl?

A

The miliosmoles is 2x the mmolarity.

1mmol NaCl = 2 mOsm

17
Q

What is the osmolarity of the ECF and ICF typically? How does this change throughout the body?

A

280 - 300 mOsm/L

Nearly identical in all major body compartments.

18
Q

Define osmolality?

When does osmolarity ~= osmolality?

A

mOsm/Kg solvent (water)

In relatively dilute solutions such as those found in the body.

19
Q

What is osmotic pressure?

When can dissolved particles exert osmotic pressure?

A

The force that dissolved particles (osmolytes) exert., which tends to pull water across a semiperm membrane.

Only can exert osmotic pressure if it is not permeable to the membrane,

20
Q

How do you calculate osmotic pressure?

What is the osmotic pressure of plasma at 37 degrees C?

A

p = CRT

C=concentration
R=constant
T=temp

At 37 degrees C, osmotic pressure = 19.3 X 282 mOsm/L = 5443 mmHg

21
Q

Define osmosis

A

Movement of water across a semi-perm membrane due to differences in osmolarity (osmotic pressure gradient)

22
Q

What is tonicity?

A

A term used in reference to the influence of the solution on the volume of a cell.

23
Q

Define isotonic, hypertonic, and hypotonic?

A

Solutions that do not change the cell are isotonic.

Hypertonic solns make the cell shrink.

Hypotonic solns make the cell swell.

24
Q

How does the distribution of fluid between the plasma and interstitial fluid change?

A

Barrier is capillary membrane, and the distribution is governed by starling forces.

25
Q

How can the net force of movement across the capillary membrane be described?

A

Flux = (Kf) [Pc + Piif - Pip - Pif]

Kf = ultrafiltration coefficient 
Pc = capillary hydrostatic pressure 
Piif - interstitial oncotic pressure 
Pip = plasma oncotic pressure 
Pif = interstitial hydrostatic pressure
26
Q

What is the ultrafiltration coefficient (Kf) a function of?

A

Surface area for exchange and the hydraulic permeability of the membrane.

27
Q

What is the oncotic (colloid osmotic) pressure due to?

A

The force due to proteins.

Recall that the protein concentration in the capillaries is greater than that of the interstitial fluid.

28
Q

The flux across capillaries is a function of ____________? In general what do these forces favor?

A

Permeability of the capillary and the net sum of hydrostatic and oncotic forces.

In general, forces favoring filtration (cap hydrostatic + interstitial oncotic) will slightly exceed those opposing filtration > leading to a net filtration.

29
Q

What occurs when a volume of fluid is added to the body?

A

It will act rapidly to achieve osmotic equilibrium by moving water across the membrane.

30
Q

What is the influence of adding isotonic NaCl to the ECF on total body water (TBW), ECF Vol, and ICF vol?

A

TBW will increase, ECFV will increase and ICFV will stay the same.

31
Q

What is the influence of adding hypertonic NaCl to the ECF on total body water (TBW), ECF Vol, and ICF vol?

A

TBW will increase, ECFV will increase, and ICFV will decrease.

32
Q

What is the influence of adding hypotonic NaCl to the ECF on total body water (TBW), ECF Vol, and ICF vol?

A

TBW will increase, ECFV will increase, and ICFV will increase.

33
Q

Describe numerically hypernatremia and hyponatremia?

A

Elevated plasma Na+ >150 mEq/L

Reduced plasma Na+ <135 mEq/L

34
Q

Describe numerically hyperkalemia and hypokalemia?

A

Elevated plasma K+ >5 mEq/L

Reduced plasma K+ <3.5 mEq/L

35
Q

Describe numerically hypercalcemia and hypocalcemia?

A

elevated plasma Ca++ >10 mg/dl

reduced plasma Ca++ <8 mg/dl

36
Q

Define acidosis and alkalosis numerically

A

reduced plasma pH <7.3 elevated plasma pH >7.5

37
Q

What is edema? What is it commonly caused by?

A

Excess fluid in the tissues (interstitium).

Commonly caused by alteration in starling forces in the systemic capillaries, leading to increased capillary filtration.

Common causes include elevated capillary hydrostatic pressure, drop in cap oncotic pressure, or lymphatic blockage.

38
Q

Name three common causes of edema?

A

Elevated venous pressure (heart failure), loss of plasma protein (cirrhosis of liver or nephrotic syndrome), and lymphatic blockage.

Physiology Block 3 (17 decks)

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