2 - Osmosis, Tonicity, and Pressures

_____ is the flow of water across a semipermeable membrane due to differences in solute concentration (membrane blocks movement of solute)

osmosis

Concentration difference of solutes causes difference in _____, which will cause osmosis

osmotic pressure

Osmosis is diffusion of water. True or false?

false

Osmosis occurs because of a difference in _____

pressure

If one side has more solute, it has [lower/greater] osmotic pressure

greater

Osmotic pressure is a [pushing/pulling] pressure

pulling

Hydrostatic pressure is a [pushing/pulling] pressure

pushing

_____ is pressure exerted by a stationary fluid at equilibrium - causes water/fluid to move or be pushed

hydrostatic pressure

Why are osmotic and hydrostatic pressures very important in cells and blood vessels?

allow fluid exchange across capillaries

Due to hydrostatic pressure, water and some very small solutes [enter/leave] blood vessels

leave

With tissues and cells, osmotic pressure is referred to as _____ or _____

colloidal osmotic; oncotic pressure

High osmolarity (many solute particles) exerts [high/low] osmotic pressure to pull water into a space, such as a blood vessel

high

Pressures favor filtration out of capillaries and into tissues. True or false?

true

Osmolar concentrations express the osmotic strength of solutions such as ___, ___, and ___

urine; plasma; NaCl

Osmolarity is the concentration of _____ per _____ of solution (osm/Lor mOsm/L)

osmotically active particles; liter

A 1 mmol/L NaCl solution would

have an osmolarity of _____ mOsm/L

2

[Osmolarity/osmolality] is the concentration of osmotically active particles per liter of solution (osm/Lor mOsm/L

osmolarity

[Osmolarity/osmolality] is the concentration of osmotically active particles expressed as osmoles/kg of water

osmolality

Osmolality is functionally the same as osmolarity. True or false?

true

Solutions of equal solute concentrations are known as _____

isosmotic

Refers to solution with higher concentration of solute

hyperosmotic

If a solution has the same osmolarity/equal osmotic pressures we call it _____

isosmotic

If a solution has higher osmolarity compared to another solution we call it _____

hyperosmotic

Refers to solution with lower concentration of solute

hypo-osmotic

If a solution has a lower osmolarity compared to another solution we call it _____

hypo-osmotic

A hypo-osmotic solution exerts [more/less] pressure

less

Review

reviewed

A measure of the effective osmotic pressure

tissue tone

_____ is defined by the response of cells or tissues immersed in the solution

tonicity

A solution is _____ to cells/tissues if cells/tissues neither swell nor shrink when immersed in solution

isotonic

A solution is _____ to cells/tissues if cells/tissues swell when immersed in solution

hypotonic

A solution is _____ to cells/tissues if cells/tissues shrink when immersed in solution

hypertonic

No osmotic pressure difference between cell interior and extracellular solution

isotonic

More solutes inside cell (higher osmolarity) relative to extracellular environment, greater osmotic pressure inside cell

hypotonic

Less solutes inside cell (lower osmolarity) relative to extracellular environment, greater osmotic pressure outside cell

hypertonic

Review

reviewed

Form of osmotic pressure specifically exerted by proteins, mostly albumin, within blood vessels

oncotic pressure

Oncotic pressure is specifically exerted by _____, mostly albumin, within blood vessels

proteins

Oncotic pressure tends to pull water [into/out of] blood vessels

into

Oncotic pressure opposes _____ pressure (tissue proteins that want to pull water out of vessels)

interstitial colloidal osmotic

Edema is a decrease in _____

blood oncotic pressure

A solution is _____ to cells/tissues if cells/tissues swell when immersed in solution

hypotonic

Solutions of equal solute concentrations

isotonic

Why does water move, in relation to osmosis?

osmotic pressure

The semipermeable membrane is permeable to _____, but not to _______

solvent; solute

Can solute move across a semipermeable membrane? What about solvent, like water?

solute - no

water - yes

Lot of solute = [greater/lesser] osmotic pressure -> _____

greater; osmosis

If there was equal amount of solute on each side, would water move?

no

More solute on one side = greater osmotic pressure = [push/pull] water to that side of the membrane

pull

Hydrostatic pressure = [pushing/pulling] pressure

pushing

-Pressure exerted by a stationary fluid

-"More fluid -> more pressure to move -> driving force" (think of watering hose)

hydrostatic pressure

More fluid in blood vessels = [more/less] pressure

more

Substances move out of capillaries and into tissues due to _____

hydrostatic pressure

Osmotic and hydrostatic pressure play a role in cells and blood vessels at the same time. True or false?

true

Generally, _____ is the dominant pressure between blood vessels and tissues

hydrostatic pressure

Osmotic pressure = [in/out] of blood vessels

Hydrostatic pressure = [in/out] of blood vessels

in; out

Hydrostatic pressure is due to _____, while osmotic pressure is due to _____

fluids; solutes

Pressure exerted by fluids between cells and tissues

interstitial hydrostatic pressure

Pressure exerted by fluid within the blood vessels (usually high b/c most cominant)

blood hydrostatic pressure

With dehydration, blood volume [increases/decreases]. Does the blood hydrostatic pressure increase or decrease?

decreases; decrease

Hydrostatic pressure opposes _____ pressure

osmotic

_____ pressure tends to pull water, while _____ pressure tends to push

osmotic; hydrostatic

Many solute particles (high conc.) = [high/low] osmolarity

high

Concentration of solute increases in the blood vessel & more water begins to be pulled in. What will happen to blood pressure?

increase

If a lot of fluid leaves the blood vessel and enters tissues, what happens?

edema

_____ pressure is dominant

hydrostatic

Pressures favor filtration [in/out] of capillaries into tissues in a normal, healthy, situation

out

1kg of water (osmolality) = ~ _____ L (osmolarity)

1

Equal solute concentrations -> same osmolarity -> same osmotic pressure

isosmotic

What happens to a normal cell placed in an isosmotic solution?

nothing

Solution with higher concentration of solutes -> higher osmolarity -> higher osmotic pressure

hyperosmotic

What happens to a normal cell placed in a hyperosmotic solution?

water moves from cell to solution -> cell shrivels up

What happens to a normal cell placed in a hypoosmotic solution?

water moves into cell from solution -> cell explodes/lyses

Tonicity is a measure of the effective _____ pressure

osmotic

Isotonic = _____

isosmotic

Cell/ tissues swell = solution is _____tonic to cell/tissue

hypo

Cell/tissues shrink = solution is _____tonic to cell/tissue

hyper

Oncotic pressure is pressure specifically exerted by _____ within blood vessels

proteins

Most of the protein within blood is _____

albumin

We have a much [higher/lower] blood oncotic pressure because of the proteins, compared to within the tissue space

higher

Decrease in oncotic pressure is associated with tissue _____

edema