Lecture 2 - Body fluids and membrane transport Flashcards

1
Q

Average body mass distribution of a 30-year-old 70kg male

A

18% fat
22% lean body muscle
60% water (42 litres)

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2
Q

Breakdown of the 42 litres in body water

A

Intracellular fluid (ICF) = 25L
Extracellular fluid (ECF) = 17L

ECF is split into 3 places:
1L transcellular fluid
3L blood plasma
13L interstitial fluid

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3
Q

Transcellular fluids

A

Cerebrospinal fluid (brain)
Urine (kidney and bladder)
Gastrointestinal fluids (saliva, bile etc)
Aqueous and vitreous fluids (eye)
Synovial fluids (joints)
etc

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4
Q

Plasma membrane: how permeable is it, what does it contain, and what does it do?

A

Highly selective permeability

Lots of transport proteins for uptake and removal of specific solutes

Vital for the regulation of the intracellular environment

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5
Q

Plasma membrane permeability: what things are impermeable and what facilitates movement through the membrane?

A

The phospholipid bilayer is impermeable to ions and polar molecules

Permeability is provided by membrane proteins:
channels
carriers
pumps

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6
Q

Carrier proteins in the membrane

A

Facilitator - uniport (one molecule moving)
Cotransporter - symport (two molecules moving the same direction)
Exchanger - antiport (two molecules moving in opposite directions)

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7
Q

Water and solutes in ICF:
K⁺
Na⁺
Ca²⁺
Cl⁻
Organic solutes⁻
Proteins⁻

A


High
Low
Very low
Low
High
High

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8
Q

Water and solutes in ECF:
K⁺
Na⁺
Ca²⁺
Cl⁻
Organic solutes⁻
Proteins⁻

A


Low
High
Low
High
Low
Low

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9
Q

Damari is a loser.

A

TRUE

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10
Q

Capillary endothelium

A

A very thin layer of cells lining blood vessels

Highly permeable in some organs, not in others (e.g. brain)

An important role in the regulation of the interstitial fluid

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11
Q

Epithelia: where are they located and what do they do?

A

layers of cells covering the internal and external surfaces of organs and tissues

  • protective/barrier function
  • important roles in absorption and secretion
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11
Q

Epithelial transport into the cell from the gastrointestinal tract

A

Glucose passes from the gut lumen, through the apical membrane, and the basolateral membrane and then into the cells.

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12
Q

Epithelial transport out of the cell into the gastrointestinal tract

A

Na⁺, K⁺, and Cl⁻ pass from inside the cells, through the basolateral membrane, through the apical membrane, and then outside of the cell into the gut lumen.

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