12. Clinical II - Body Fluids and Homeostasis Flashcards

1
Q

the MAJOR BODY CONSTITUENT is WATER.
an average person contains how much water

A

42 LITRES

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2
Q

MAJORITY of body WATER is found in which COMPARTMENT

A

INTRACELLULAR - 28L

2/3rds of body water

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3
Q

approx how much body water is found in EXTRACELLULAR COMPARTMENT

A

14L, 1/3rd

  • 11L INTERSTITIAL (Interstitial fluid)
  • 3L INTRAVASCULAR (in PLASMA)
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4
Q

where is the MAJORITY of WATER in the EXTRACELLULAR COMPARTMENT

A

in INTERSTITIAL FLUID (surrounding cells)

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5
Q

is there more water INTRACELLULAR or in INTERSTITIAL FLUID (fluid in the spaces around the cells)

A

INTRACELLULAR - 28L

  • INTERSTITIAL 11 L
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6
Q

what is the TOTAL DAILY INTAKE and OUTPUT of WATER

A

2300 ML intake

2300 ML output

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7
Q

total amount of FLUID in the body is approximately how much of BODY WEIGHT

A

55-60% of body weight

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8
Q

FLUID in body VARIES by TISSUE TYPE. what tissue type has HIGHER FLUID CONTENT

A

LEAN TISSUES

(lean tissue is lost with age and body fluid lost with it)

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9
Q

why do MEN have MORE BODY FLUID

A

MORE LEAN TISSUE which has HIGHER FLUID CONTENT

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10
Q

the VOLUME of the FLUID COMPARTMENTS is DETERMINED by the SOLUTES that are confined in each space.

which SOLUTE for INTRACELLULAR COMPARTMENT? / what is the MAIN INTRACELLULAR CATION

A

POTASSIUM

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11
Q

the VOLUME of the FLUID COMPARTMENTS is DETERMINED by the SOLUTES that are confined in each space.

which SOLUTE for EXTRACELLULAR COMPARTMENT? / what is the MAIN EXTRACELLULAR CATION

A

SODIUM

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12
Q

what are the MAIN EXTRACELLULAR ANIONS

A

CHLORIDE & BICARDBONATE, HCO3-

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13
Q

what are the MAIN INTRACELLULAR ANIONS

A

PROTEINS & PHOSPHATE

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14
Q

is CL- a MAIN extracellular or intracellular ANION

A

EXTRACELLULAR

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15
Q

is PO4 3- a MAIN extracellular or intracellular ANION

A

INTRACELLULAR

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16
Q

is NA+ a MAIN extracellular or intracellular CATION

A

EXTRACELLULAR

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17
Q

is HCO3- a MAIN extracellular or intracellular ANION

A

EXTRACELLULAR

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18
Q

is K+ a MAIN extracellular or intracellular CATION

A

INTRACELLULAR

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19
Q

are PROTEINS MAIN intracellular or extracellular ANIONS

A

INTRACELLULAR

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20
Q

INTRACELLULAR FLUID is CALLED ….
which is the site of multiple cell processes including metabolic processes and also involved in signal transduction from the cell membrane to sites within the cell

A

CYTOSOL

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21
Q

EXTRACELLULAR FLUID comprises what % of total BODY WEIGHT

  • PLASMA?
  • INTERSTITIAL SPACE?
A

20%

plasma 5%
Interstitial space 12%

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22
Q

INTERSTITIAL FLUID (around cells) have SIMILAR SOLUTES to PLASMA EXCEPT …

A

PROTEIN content

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23
Q

KEY HORMONE in FLUID HOMEOSTASIS that REDUCES the amount of WATER LOST in URINE

A

ANTIDIURETIC HORMONE / VASOPRESSIN

from POSTERIOR PITUITARY

and on KIDNEYS (dct and collecting duct)

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24
Q

which part of the KIDNEYS REGULATE WATER OUTPUT

A

DCT and COLLECTING DUCTS of the NEPHRONS

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25
Q

what CONSUMES a LARGE PORTION of our BASAL METABOLIC RATE / ENERGY

A

MAINTENANCE of IONIC GRADIENTS across cell membranes

  • may require active transport
26
Q

uses of ELECTROLYTES:

A
  • Help to MAINTAIN FLUID BALANCE
  • contribute to ACID-BASE REGULATION
  • Facilitate ENZYME REACTIONS
  • transmitting NEUROMUSCULAR REACTIONS
27
Q

what is OSMOTIC PRESSURE

A

Minimum pressure that needs to be applied to a solution to PREVENT INWARD FLOW of its PURE SOLUTE across a semi-permeable membrane

related to the TOTAL NUMBER of PARTICLES of SOLUTE

28
Q

what is ONCOTIC PRESSURE

A

Osmotic pressure EXERTED BY PROTEINS
(due to presence of proteins, mostly ALBUMIN)

29
Q

how is OSMOTIC PRESSURE on BOTH SIDES of a CELL MEMBRANE

A

must always be THE SAME

so water will move even if it causes the cell to shrink of expand

30
Q

what are the ONLY SOLUTES that DO NOT PASS FREELY between PLASMA and INTERSTITIUM (are not filtered out of Plasma)

A

PROTEINS

31
Q

what is the MOST ABUNDANT PLASMA PROTEIN that makes the MAJOR CONTRIBUTION (about 80%) to the ONCOTIC PRESSURE

A

ALBUMIN

32
Q

How does OSMOTIC PRESSURE and ONCOTIC PRESSURE CHANGE across the length of the capillary, from arterial to venous end

A

OSMOTIC PRESSURE DECREASES
- high at arterial
- low at venous

ONCOTIC PRESSURE STAYS THE SAME THROUGHOUT

33
Q

OSMOTIC PRESSURE causes FLUID to move in what direction

A

OUTWARD FLOW

OUT OF BLOOD to be FILTERED and for EXCHANGE in interstitial fluid (at arterial end)

34
Q

ONCOTIC PRESSURE causes FLUID to move in what direction (force in what direction)

A

INWARD FLOW

PULLS FLUID BACK INTO BLOOD PLASMA at VENOUS END (where osmotic pressure is low so exceeds)

35
Q

HYDROSTATIC PRESSURE in BLOOD VESSULS is the pressure of..

A

the BLOOD AGAINST THE WALL

forced fluid OUT of capillary into interstitium
(opposing force to Oncotic Pressure)

capillaries act like a leaky hosepipe, HP forces some fluid out of walls
(large molecules and proteins cannot pass)

36
Q

where is CAPILLARY HYDROSTATIC PRESSURE HIGHER

A

At ARTERIAL END - 30 mmHg

lower at Venous end - 10 mmHg

(except in kidneys where high capillary Hps in Glomerulus mean filtration is high across full length of capillary)

37
Q

MOVEMENT of FLUID ACROSS CAPILLARIES depends on the BALANCES between:

A
  • CAPILLARY HYDROSTATIC PRESSURE & INTERSTITIAL FLUID HYDROSTATIC PRESSURE
  • PLASMA ONCOTIC PRESSURE & INTERSTITIAL FLUID ONCOTIC PRESSURE
38
Q

FLUID FILTRATION is HIGH at ARTERIAL END and LOW at VENOUS END. how does ALBUMIN CONC. CHANGE

A

INCREASES

  • HIGH at VENOUS END as more fluid has left
39
Q

what provides an ALTERNATIVE ROUTE for the TRANSPORT of FLUIDS and PROTEIN AWAY FROM INTERSTITIAL SPACES (as filtration > reabsorption into blood so excess fluid goes where)

A

LYMPHATIC SYSTEM
(system of fine lymphatic channels throughout the body passing via lymph nodes to thoracic duct)

(valves ensure one-way flow)

40
Q

LYMPH is a CLEAR, COLOURLESS FLUID that is COMPOSED of..

A

96% WATER
4% SOLIDS (proteins, lipids, carbohydrates, non-protein nitrogen, electrolytes)

41
Q

5 FUNCTIONS of LYMPH

A
  • RETURN PROTEINS from tissue spaces INTO BLOOD
  • REMOVAL of BACTERIA, TOXINS and other FOREIGN BODIES from tissues
  • MAINTAIN STRUCTURAL and FUNCTIONAL INTEGRITY of TISSUE
  • ROUTE for INTESTINAL FAT ABSORPTION (helps fat absorption as chylomicrons carried away in lymph)
  • TRANSPORT LYMPHOCYTES (immune function)
42
Q

what is an OEDEMA

A

condition where there is an
INCREASED VOLUME of INTERSTITIAL FLUID in a tissue or organ

may be localised or generalised

43
Q

CAUSES of OEDEMA (increased volume interstitial fluid)

A
  • RAISED CAPILLARY HYDROSTATIC PRESSURE and SALT/WATER RETENTION
  • REDUCED ONCOTIC PRESSURE (LOW PROTEIN in plasma)
  • IMPAIRED LYMPHATIC DRAINAGE
  • ENDOTHELIAL DAMAGE (INFLAMMATION)
44
Q

how is HYDROSTATIC PRESSURE in an OEDEMA

A

RAISED

45
Q

how is ONCOTIC PRESSURE in an OEDEMA

A

REDUCED

46
Q

How is SALT/WATER RETENTION in OEDEMA

A

RAISED
-> raising hydrostatic pressure

47
Q

what causes MINIMAL / NO REABSORPTION of FLUID at VENULAR END leading to OEDEMA

A

INCREASED HYDROSTATIC PRESSURE AT VENULAR END

EXCEEDS PLASMA ONCOTIC PRESSURE

48
Q

what can cause RAISED CAPILLARY PRESSURE (Hydrostatic) especially at VENOUS END , causing OEDEMA

A

CARDIAC FAILURE

(eg. following myocardial infarction)

49
Q

what causes REDUCED PLASMA ONCOTIC PRESSURE which can cause OEDEMA

A

REDUCED ALBUMIN / Protein SYNTHESIS in LIVER (eg LIVER FAILURE / DISEASE)
- low proteins in plasma

NET MOVEMEMENT of FLUID INTO INTERSTITIAL TISSUES

DECREASE in REABSORPTION / movement back into blood at VENULAR END

(low plasma volume triggers RAAS, na+ and H2O retention which increases likelihood of OEDEMA)

50
Q

how can ALTERATION in LYMPHATIC FLOW cause OEDEMAS

A

if NET FILTRATION > LYMPH FLOW

the INTERSTITIAL VOLUME SWELLS with FLUID
as less carried away by lymph

(due to lymphatic obstruction or tissue injury)

eg due to TUMOURS or LYMPH NODE REMOVAL

51
Q

how can LIVER DISEASE cause OEDEMA

A

REDUCED PROTEIN SYNTHESIS (albumin)

LESS PROTEINS IN PLASMA
- REDUCED ONCOTIC PRESSURE

52
Q

how can CARDIAC FAILURE cause OEDEMA

A

INCREASED CAPILLARY HYDROSTATIC PRESSURE

RAISED at VENULAR END
- EXCEEDS PLASMA ONCOTIC PRESSURE

so NO/MINIMAL REABSORPTION of FLUID BACK INTO BLOOD
(more fluid in interstitial space)

53
Q

how can TUMOURS cause OEDEMA

A

ALTERATION in LYMPHATIC FLOW

if NET FILTRATION > LYMPHATIC FLOW when INTERSTITIAL FLUID SWELLS with FLUID

54
Q

how can ENDOTHELIAL DAMAGE caused by INFLAMMATION cause OEDEMA

A

VASCULAR DILATION and INCREASED BLOOD FLOW

INCREASED CAPILLARY PERMEABILITY to PLASMA PROTEINS
proteins flow out

  • REDUCED PLASMA ONCOTIC PRESSURE

so NO/MINIMAL REABSORPTION of FLUID FROM INTERSTITIAL space

also LEUKOCYTE EMIGRATION and ACCUMULATION at site of injury

55
Q

How are BODY FLUIDS SEPARATED

A

separated into COMPARTMENTS by SEMI-PERMEABLE MEMBRANES

membranes are HIGHLY PERMEABLE to WATER but REQUIRE ENERGY to TRANSPORT IONS

56
Q

what DETERMINES the DISTRIBUTION of FLUIS between the INTRACELLULAR and EXTRACELLULAR COMPARTMENTS

A

CONC. of NA+, CL- and other ELECTROLYTES

ic - K+
ec - Na+

57
Q

OSMOTIC PRESSURE is the pressure EXERTED BY..

A

the FLOW of WATER through

58
Q

OSMOTIC PRESSURE is the pressure EXERTED BY..

A

the FLOW of WATER through a SEMI-PERMEABLE MEMBRANE separating 2 solutions with different conc. of solute

59
Q

SODIUM TRANSPORT is REGULATED by which HORMONE

A

ANGIOTENSIN II

60
Q

what HORMONE also SALT and WATER RETENTION

A

ALDOESTERONE

61
Q

RENAL DISEASES occur when the kidneys…

A

retain more sodium and water at a given arterial pressure