Bodily Fluids Flashcards

1
Q

Between what compartments in the human body is fluid distributed? How does it differ between men and women?

A
  • 55% of female body is fluids; 60% of male body is fluids
  • 2/3 of fluid is intracellular, 1/3 is extracellular
  • 75% of ECF is interstital, 20% is plasma, 5% transcellular fluid

female has less fluids bc have a higher fat content

transcellular fluid= cerebrospinal fluid, intraocular fluid, gastrointestinal fluid, bile, sweat.
- Fluid that has been secreted but is not in plasma, is seperated by endothelial layerr
- Controlled by secretery cell

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2
Q

What seperates the ICF and ECF?

intracellular fluid (ICF) and extracellular fluid (ECF)

A

Cell membranes

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3
Q

What seperates interstital fluid and plasma?

A

Capillary walls

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4
Q

Whats the difference between molarity and molality?

A
  • Molarity (mols solute/ 1L water)
  • Molality (mols solute/ 1kg solute)

Molarity= solute & water
Molality= just solute

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5
Q

In a low solute solution is there HIGH or LOW osmotic potential?

A

HIGH osmotic potential because osmosis is water diffusing from low solute to high solute

In high solute solution there is LOW osmotic potential

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6
Q

What affect does vassopressin/ADH have on body fluid osmolarity?

ADH= antidiuretic hormone= vassopressin

A
  • ADH is released when osmolality is increased or decrease in TBW
  • Causes increased water retention
  • released by hypothalamic osmoreceptors, which also release thirst signals

TBW= total body water = 0.6x body weight (~42 L)

Increased osmolality/ decreased TBW triggers hypothalamic receptors

This hypothalmus/kidney/thirst mechanism regulates ECF osmolality

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7
Q

What is the Gibbs- Donnan effect?

A

When there is an unequal distribution of permeable ions across a semi-permeable membrane in the presence of a moleucle that is impermeable

water flows UP osmotic pressure gradient, and Na pump pumps Na out so that cell doesnt explode

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8
Q

What is colloid osmotic pressure?

A
  • Aka oncotic pressure
  • osmotic pressure inside the plasma of blood cells
  • Caused by proteins (usually albumin) that cant permeate the membrane that binds it
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9
Q

What are the levels of Na+, K+ and Cl- in ECF and ICF?

A

ICF: LOW Na, HIGH K+, LOW Cl-
ECF: HIGH Na, LOW K+, HIGH Cl-

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10
Q

How would a volume osmolarity diagram change due to dehydration?

A

Volume decrease and osmolality increase in both ICF and ECF

ECF would decrease from water moving into cells, thus the osmolality would increase from the solutes left behind
Cell is now in a hypertonic soln so water would leave the cell thus raising osmolality

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11
Q

Which way does water move in a…
- hypotonic solution
- hypertonic solution
- isotonic solution

A

Hypotonic: water moves into cell
Hypertonic: water moves out of cell
Isotonic: no net water movement

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12
Q

Whats the difference between filtration and diffusion?

A

Both are passive transport
Filtration driven by osmotic pressure
Diffusion driven by solute concentration gradient

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13
Q

Where are AQPI and AQPII found?

A

AQPI found in most cells
AQPII is only in the kidney collecting duct and is sensitive to ADH

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14
Q

How is cell volume generally controlled?

A

Cell volume can be regulated by altering the cell’s solute load (osmotically active particles).
Metabolism not only powers solute movement in or out of cell, but affects production/breakdown of polymers (glycogen, proteins) in the cytoplasm.

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15
Q

What does the sodium pump do?

A

Pumps 3 Na OUT and 2 K IN per ATP

(pumps ions against their conc gradients) (+1 net charge per pump)

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16
Q

How does osmotic and hydrostatic pressure drive water across capillary walls?

A

If hydrostatic > osmotic = fluid leaves capillary
If hydrostatic < osmotic = fluid enters capillary

Filtration happens when capillary hydrostatic pressure is greater than the outside blood colloidal osmotic pressure

Reabsorption happens when capillary hydrostatic pressure is less than the outside blood colloidal osmotic pressure

17
Q

Whats Starlings hypothesis?

A

The extent of water and small solute transit in any one direction across a capillary is dependent upon the balance of two opposing forces

If Jv is positive fluid leaves the capillary (filtration),
If Jv is negative fluid enters the capillary (reabsorption)

Jv = net fluid movement

When reflection coefficient=1 = barrier is impermeable to protein
When reflection coefficient= 0 barrier is totally permeable

18
Q

Why is vasomotion important in fluid reabsorption?

A

Vasomotion= closure of precapillary sphincters
Vasomotion causes drop in Pcap

Pcap= Capillary hydrostatic pressure

Precapillary sphincters= is a band of smooth muscle that adjusts blood flow into capillaries

19
Q

What are the functions of the lymphatic system?

A
  • return interstitial fluid and proteins to the blood
  • transport dietary fats to adipose tissue
  • protect against cancer & infection
  • resistance - fight off disease
  • nonspecific resistance - general protection against disease
  • immunity - specific protection

more fluid leaves blood capillaries through filtration than is returned by absorption (Starlings law)
3L of lymph fluid is generated per day
Proteins that have escaped from blood or secreted by tissues are returned
Lymph flow is facilitated by muscle pumps, the respiratory pump, valves, and smooth muscle (in the walls of the trunks & thoracic duct)