Brainscape's Knowledge GenomeTM

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


See full index

Kidneys and Renal functions > Intro to Kidneys & Body Fluid > Flashcards

Intro to Kidneys & Body Fluid Flashcards

1
Q

How much of our body weight is made up of water?

A

Total body water: 60% body weight

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

How much of our body weight is composed of intracellular water?

A

Intracellular water: 40% body weight (ICF compartment)

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

How much of our body weight contributes to ECF?

A

Extracellular water: 20% body weight (ECF compartment)

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

How does water move between ICF and ECF?

A

Osmosis determines movement of water between ICF and ECF

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

Describe the water content of a 70kg average man

A

A 70kg man,
60% water by weight: total body water is 42 L
40% body weight will be intracellular (ICFV = 28L)
20% extracellular (ECFV = 14L)

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

What are the 2 components of ECFV?

A

The ECFV consists of two sub-compartments:

  • Plasma (3L)
  • Interstitial fluid (11L)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do substances move between plasma and Interstitial fluid?

A

Starling forces from capillary filtration determine fluid and solute movement between plasma and interstitial fluid

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

What is osmolarity?

A

Total concentration of osmotically active solutes

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

How is movement between ICF and ECF regulated?

A

Solute composition of ECF and ICF differs, but osmolarity must be kept the same to avoid excessive shifts of water between ECF and ICF

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

What determines ECF osmolarity?

A

Sodium is the principal electrolyte of the ECF, therefore sodium (with associated anions) is the major determinant of ECF osmolarity

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

What is the significance of body fluids?

A

Cell structure + function
- Large shifts between ECFV / ICFV disrupts tissue
structure + function

Tissue perfusion

  • Depends on balance between circulating volume
    (plasma) + interstitial volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What 2 key processes determine salt and water balance?

A

Osmoregulation and volume regulation

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

What is osmoregulation?

A

The maintainance of osmotic equilibrium between ICFV and ECFV

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

What is meant by volume regulation?

A

Maintaining adequate ECFV to support plasma volume

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

How is plasma osmolarity estimated?

A

2[Na] + 2[K] + [glucose] + [urea] (all in mmol L-1)

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

How is osmolarity of a solution changed?

A
  1. Add/remove solute

2. Add/remove water

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

How does the body achieve osmoregulation?

A

The body accomplishes osmoregulation by adding or removing water not sodium

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

Explain the effect of increasing plasma osmolarity

A

Plasma osmolarity rises – more water needed

Kidneys respond by producing small volume of concentrated urine (water retention)

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

What is the effect of decreasing plasma osmolarity?

A

Plasma osmolarity falls – too much water

Kidneys respond by producing large volume of dilute urine (water excretion)

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

What is volume regulation referring to?

A

Refers specifically to the control of the circulating (plasma) volume

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

How does the body achieve volume regulation?

A

Changes detected by stretch / pressure receptors in CVS

A fall in blood volume is opposed by Na retention; water follows osmotically, restoring volume

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

What is the main function of the kidneys?

A

Kidney function is homeostasis

Urine is a by-product of kidney function

23
Q

What is the significance of the urinary tract?

A

The urinary tract is important for temporary storage and then to remove the urine from the body

24
Q

List the functions of the kidneys

A
  • Osmoregulation
  • Volume regulation
  • Acid-base balance
  • Regulating electrolyte balance (eg k+, Ca2+, phosphate)
  • Removal of metabolic waste products from blood
  • Removal of foreign chemicals in the blood (e.g. drugs)
  • Regulation of rbc production (erythropoietin)
25
Q

What is a nephron?

A

Basic unit of structure in the kidney

26
Q

Outline the structural features of nephrons

A

Consists of special blood vessels and elaborate tubules (tiny tubes)
Microscopic, structures
1.25 million per kidney
Where urine production begins

27
Q

What major structures does each nephron consist of?

A
  • Blood vessels
    • The glomerulus
    • Bowman capsule
    • The renal tubule
28
Q

Which major vessels supply the kidneys?

A

Common Iliac artery

Inferior vena cava

29
Q

Outline the blood vessels allowing perfusion through kidneys

A 
Renal. A
↓
Segmental. A
↓
Interlobular. A
↓
Arcuate . A
↓
Interlobular. A
↓
Afferent arterioles
↓
Nephrons
↓
Venules
↓
Interlobular. V
↓
Arcuate. V
↓
Interlobular. V
↓
Renal Vein
30
Q

How is the kidney supplied with blood?

A

The whole kidney is supplied by the renal artery which subdivides many times into fine arterioles supplying each nephron, the afferent arteriole

31
Q

How is renal blood drainage carried out?

A

Drained by the renal vein, which is supplied by venules coming away from each nephron, joining together into larger veins which merge into the renal vein

32
Q

What is between the arterioles and venules?

A

Complex capillary networks

33
Q

What is the process of urine formation

A
  1. Glomerular Filtration
  2. Tubular Reabsorption
  3. Tubular Secretion
  4. Excretion of water + solutes in urine
34
Q

What is glomerular filtration?

A

(GFR) - first step in urine production

=> amount of filtrate kidneys produce each minute (125 ml/min)

35
Q

What affect does renal failure have on GFR?

A

GFR is reduced in renal failure

36
Q

Explain how glomerular filtration occurs

A

Hydrostatic pressure forces fluids + solutes through glomerular capillary membrane
Small molecules pass readily- large (proteins) and cells can’t pass
=> leads to plasma ultrafiltrate in Bowman’s capsule

37
Q

What is reabsorption?

A

Many substances are filtered and then reabsorbed from the tubular lumen into the peritubular capillaries

38
Q

What is the significance of Tubular secretion?

A
  • Disposing substances not already in filtrate
  • Eliminating undesirable substances e.g. urea + uric acid
  • Ridding the body of excess K+ ions
  • Controlling blood pH
39
Q

How is excretion of fluid and solutes regulated?

A

[ ] of any solute present in urine is given by the amount filtered out of plasma - amount reabsorbed + amount secreted

40
Q

How is water and sodium balance maintained?

A
  1. Changes in water intake/excretion
  2. Changes in body fluid osmolarity
  3. Sensors (e.g. sensory cells in hypothalamus) detect
    new ECF osmolarity
  4. Effectors (kidneys) adjust amount of water excreted /
    retained
  5. Change in renal water excretion
    => Intake = output
41
Q

What is the effect of intake / output mismatch?

A

Mismatch of intake and output will cause a change in osmolarity
Shift of water between ICFV and ECFV

42
Q

What can cause water restriction?

A

Loss of water (sweat, breathing). Thirsty, but no water is available to drink

43
Q

What is the physiological response to water restriction?

A

Plasma osmolality rises

Response is increased secretion of hormone, ADH

44
Q

What is the effect of ADH on water restriction?

A

Results in

  • Decreased urine volume
  • Increased urine osmolality
45
Q

What is the effect of increased water intake?

A

Increase in water absorption through GIT

  • Plasma osmolality falls
  • Response is reduced secretion of ADH
46
Q

What does reduced ADH cause?

A

Results in

  • Urine volume increases
  • Urine osmolality decreases
47
Q

What is the normal plasma osmolality?

A

Plasma osmolality is maintained (~280 - 300 mOsmol/Kg) in face of changes in water intake by retaining or by excreting water

48
Q

How is plasma osmolality maintained?

A

Done by ADH system, kidneys & behavioural thirst response

49
Q

What determines ECF volume?

A

ECF volume is determined by the amount of sodium in this compartment

50
Q

How is ECFV maintained?

A

Sodium intake and excretion must be balanced to maintain constant ECF volume
Main volume sensors are in the cardiovascular system

51
Q

What is the physiological response to low blood volume?

A

A fall in blood volume is opposed by hormonal signals promoting sodium retention; water follows osmotically, restoring volume

52
Q

How is sodium balance maintained?

A

The maintenance of sodium balance is based (mainly) on the control of the ECFV
Intake ~ output

53
Q

What hormone systems contribute to Na balance?

A

Sodium retaining:
- RAAS

Sodium Eliminating:
- ANP

54
Q

Explain how the hormone systems respond to a decreased ECFV

A
  1. Low ECFV / ↓Na excretion
  2. ↓ANP
  3. ↑RAAS

Kidneys and Renal functions (14 decks)

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