DENT Fun. I - Solutes & Water Movement

Comparator

Interprets input from sensors to determine when deviations from set point have occurred; If deviated, a counter-response is initiated

Blood plasma osmolarity is ____.

290 mmol/L

The biological membrane is ____.

semi-permeable

Osmolarity

Total concentration of all solute particles in a solution

What are the 3 Fluid Compartments?

- Plasma

- Interstitial Fluid

- Intracellular Fluid

Most proteins are located in the ____.

intracellular fluid

Transcellular Fluid

The fluid that is contained within specialized body compartments such as cerebrospinal, pleural, and synovial cavities

What molecules are freely permeable?

- Gases

- Small, uncharged

What molecules require "assistance" to move across the Plasma Membrane?

Large, charged molecules

Negatively charged Lipids are placed on the ____.

inner membrane

Lipids can flip from the outer to inner membrane freely (T/F)

False; requires an enzyme, flipase

Cell Membrane Composition

- Integral Proteins

- Peripheral Proteins

- Glycoproteins

- Glycolipids

- Cholesterol

Cholesterol

- Immobilizes the outer membrane

- Reduces permeability

- Decreases freezing point

What are the 6 Integral Membrane Proteins?

- Channels

- Carriers

- Cell Recognition

- Receptors

- Enzymes

- Linkers/Structural: Involved in cell-cell attachment and serve as scaffolds for cytoskeleton

Diffusion

Passive movement of an uncharged substance from high to low concentration due to random thermal motion

Diffusion is proportional to the ____ and ____ of a semi-permeable membrane.

cross-sectional area/concentration of solute

Diffusion is inversely proportional to the ____ of a semi-permeable membrane.

thickness

The ability for a molecule to move across a membrane depends on what 3 variables?

- Concentration Gradient

- Charge (Lipophilic/Lipophobic)

- Size

Osmosis

Diffusion of water through a selectively permeable membrane toward areas of high solute concentration

Osmotic Pressure depends on what 2 factors?

- Concentration of solute

- The ability for particles to cross the membrane

Does not depend on mass or size of molecule

Hydrostatic Pressure

The pressure within a vessel that tends to push water out of the vessel

Starling Forces

- Hydrostatic + Oncotic pressures

- Balance of these forces maintains proper fluid volumes & solute concentrations inside & outside the vasculature

- Imbalance of these pressures results in too little or too much fluid in tissues

Isotonic

When the concentration of two solutions is the same

Hypertonic

Having a higher concentration of solute

Hypertonic solution will cause cells to shrink

Hypotonic

Having a lower concentration of solute

Hypotonic solution will cause cells to swell

Facilitated Diffusion

Passive movement of specific molecules across cell membranes through protein channels

Active Transport

Energy-requiring process that moves material across a cell membrane against a concentration gradient

What are the 2 types of AT?

- Primary

- Secondary

Primary Active Transport

- Direct hydrolysis of ATP

-

Na+/K+ Pump

- AT pump that pushes 3 Na+ out and 2 K+ in

- Essential for maintaining cell volume and establishing concentration gradients for neuronal activity

Secondary Active Transport

Form of active transport which does not use ATP as an energy source; rather, transport is coupled to ion diffusion down a concentration gradient established by primary active transport

Vmax

The saturation of all transport sites; The highest rate at which a molecule can be transported across a membrane