1 - Body Fluid Compartments & Transport Across Cell Membranes

true

Total water in the body = total body water. True or false?

60

Total body water is ~_____% of body weight

40

Intracellular fluid is ~___% of body weight

20

Extracellular fluid is ~___% of body weight

1. interstitial fluid

2. plasma

What are the 2 components of extracellular fluid, split by a capillary wall?

16

Interstitial fluid is ~___% of body weight

4

Plasma is ~___% of body weight

cell membrane

Intracellular and extracellular fluid are split by what structure?

capillary wall

Interstitial fluid and plasma are split by what structure?

6-8%

Blood volume is ___-___% of body weight

60-80

Blood volume is ___-___mL/kg of body weight

fat

The amount of water in the body is inversely related to the amount of _____

12L

A 20kg dog has ~12L of total body water

20kg x 0.6 = 12kg = 12L

**0.6 = 60% (average total body water)

How much total body water does a 20kg dog have?

21L

A 105kg pig has 21L of extracellular fluid

105kg x 0.2 = 21L or 21,000mL

What is the ECF (total extracellular fluid) volume of a 105kg pig?

70mL/kg

What is the average blood volume in comparison to body weight?

amounts

We measure [amounts/concentrations] in moles, equivalents, or osmoles

concentrations

We measure [amounts/concentrations] in mol/L or mmol/L, mEq/L, Osm/L, or mOsm/L

amount of charged solute

What is an "equivalent"?

# of particles into which a solute dissociates in solution

What is an "osmole"?

osmoles/L

Osmolarity is measured in _____/_____

pH

What expresses H ion concentration?

low

H ion concentration in body fluids is [low/high], and is, therefore, expressed as a logarithmic term (pH)

-log10[H+]

pH = ?

cations; anions

Each body fluid compartment must have the same concentration of _____ as ____

each body fluid compartment must have the same concentration of cations as anions

What is electroneutrality?

Na+

What is/are the major cation(s) in ECF?

Cl- and HCO3-

What is/are the major anions(s) in ECF?

K+

What is/are the major cation(s) in ICF?

proteins and organic phosphates

What is/are the major anion(s) in ICF?

low; more

ICF is [high/low] ionized Ca2+ and [more/less] acidic

true

The osmolarity is the same in ECF and ICF. True or false?

electroneutrality

Because the osmolarity of ECF and ICF are the same, what is able to be maintained?

No - they are selectively permeable

Are cell membranes freely soluble to all solutes? Why?

1. Na+/K+ ATPase pump

2. Ca2+/ATPase pump

BOTH use ATP directly

What are the 2 transport mechanisms in the cell membrane? Do they directly use ATP?

1. glucose

2. amino acids

3. Ca2+

4. H+

What transporters DONT directly use ATP/energy in the cell membrane?

Na+ gradient

Since transporters for glucose, amino acids, Ca2+, and H+ dont directly use energy, what do they utilize?

1. allows nerve and muscle cells to have resting membrane potentials (due to K+ difference) K for killed

2. upstroke of action potentials in nerve and muscle cells, and absorption of nutrients (due to Na+ difference) N for nutrients

3. excitation-contraction coupling in muscle cells (depends on Ca2+ difference) C for contraction and coupling

Why are ion concentration differences important (3)?

K+

Nerve and muscle cells have resting membrane potentials due to difference in _____.

Na+

The upstroke of action potentials in nerve and muscle cells, and absorption of nutrients is due to difference in _____.

Ca2+

Excitation-contraction coupling in muscle cells is due to difference in _____.

1. lipids

2. proteins

Cell membranes are composed of what 2 things?

1. phospholipids

2. cholesterol

3. glycolipids

Cell membranes are composed of what 3 lipids?

1. transporters

2. enzymes

3. hormone receptors

4. antigens

5. ion channels

6. water channels

Cell membranes are composed of what 6 proteins?

1. integral proteins

2. peripheral proteins

What are the 2 types of proteins found in cell membranes?

integral

[Integral/peripheral] proteins can be transmembrane proteins, such as hormone/neurotransmitter receptors, pores, or ion channels.

glycerol backbone; FA tails

The phospholipid component of cell membranes consists of _____ (water-soluble) and _____ (lipid-soluble)

water

The glycerol backbone of the phospholipid component of a cell membrane is [water/lipid] soluble

lipid

The FA tails of the phospholipid component of a cell membrane is [water/lipid] soluble

lipid bilayer

The glycerol backbone and FA tails of the phospholipid component of a cell membrane helps to form what?

electrochemical gradient with no input of energy

Transport across cell membranes can occur down or against an _____

down

Simple or facilitated diffusion can occur [down/against] an electrochemical gradient

against

Primary or secondary transport can occur [down/against] an electrochemical gradient

does not

Simple or facilitated diffusion [does/does not] need an input of energy

primary

[Primary/secondary] transport utilizes a direct input of energy

secondary

[Primary/secondary] transport utilizes an indirect input of energy

is not (Facilitated diffusion uses a carrier, but does not require energy)

Simple diffusion [is/is not] carrier mediated

equilibrate

When two solutions are separated by a membrane permeable to the solute, the solute will _____ across the membrane

1. concentration gradient

2. partition coefficient

3. thickness of membrane

4. surface area

5. diffusion coefficient

What are the 5 factors that movement of solute depends on?

higher

Greater surface area = [higher/lower] diffusion rate

lower

Lower surface area = [higher/lower] diffusion rate

concentration gradient

What is the "driving force" for the movement of solutes across a membrane?

partition coefficient

What solute movement factor is based on lipid solubility of the solute?

diffusion coefficient

What solute movement factor is based on the size of the solute and viscosity of the solution?

diffusion

A potential difference across a membrane will alter the rate of _____ of a charged solute

slow down

Diffusion of a positively-charged ion will [speed up/slow down] if diffusing into an area of positive charge

positive

Diffusion of a positively-charged ion will slow down if diffusing into an area of [positive/negative] charge

down

A diffusion potential can be created when a charged solute diffuses [up/down] its concentration gradient

diffusion potential

A _____ can be created when a charged solute diffuses down its concentration gradient

carrier

Facilitated diffusion uses a _____ protein, with NO input of energy

due to limited # of carriers

Example: GLUT4 transporter in skeletal and adipose tissue

• Transports glucose into cells

• D-galactose also competes for binding

Why does facilitated diffusion proceed faster at relatively low solute concentrations?

1. saturation

2. stereospecificity

3. competition

What are the 3 features of carrier-mediated transport?

increases

Carrier proteins have limited # of binding sites for solute, therefore, the rate of transport [increases/decreases] at a higher rate at lower solute concentrations

lower

Carrier proteins have limited # of binding sites for solute, therefore, the rate of transport increases at a higher rate at [lower/higher] solute concentrations

false

Binding sites for solute on carrier proteins are not specific. True or false?

chemically

Although binding sites are specific, carriers may recognize and bind _____-related solutes

primary active

In _____ transport, one or more solutes move against a concentration gradient directly using ATP

Na+/K+ ATPase

Which pump is present in membranes of ALL cells?

3; 2

During primary active transport, ___ Na+ is pumped to ECF and ___ K+ is pumped to ICF by the Na+/K+ ATPase pump, creating a charge separation and potential difference

cardiac glycosides

What inhibits the Na+/K+ ATPase pump/protein transporter?

H+/K+ ATPase

Parietal cells of the gastric mucosa use what pump to pump H+ into the lumen of the stomach?

secondary active

_____ transport indirectly uses energy by utilizing the Na+ gradient to transport solutes against their concentration gradient

Na+

Secondary active transport indirectly uses energy by utilizing the _____ gradient to transport solutes against their concentration gradient

the same

In secondary active transport, all solutes are transported in [different/the same] direction(s)

1. Na+/glucose co-transporter (SGLT1)

2. Na+/amino acid co-transporter

What are the 2 co-transporters, in secondary active transport, in the intestine and renal tubule?

Na+/K+/2Cl- co-transporter

What is the co-transporter, in secondary active transport, in the renal tubule, but NOT in the intestine?

symport

Co-transport is [symport/antiport]

antiport

Counter-transport is [symport/antiport]

counter

With [co/counter] transport, solutes move in opposite directions

into; out

With counter-transport, Na+ moves [into/out of] the cell, while other solutes move [in/out]

1. Ca2+/Na+ exchange

2. Na+/H+ exchange

What are the 2 exchanges that occur during counter-transport?

1kg

1L of water = ~____ of body weight

more

More muscle = less fat = [more/less] water

less

More fat = less muscle = [more/less] water

plasma

Liquid portion of blood found within blood vessels

interstitial fluid

Liquid that surrounds/bathes cells and tissues

capillary wall

Thin layer of tissue in blood vessels that allows substances to pass between blood and tissues

equivalents

Charged particles/L

osmoles/milliosmoles

How many particles that a solute is going to dissociate into in a solution

cations; anions

Each body fluid compartment ALWAYS has to have the same number of _____ and _____

negatively

Proteins are [positively/negatively] charged