Test 1 Study Guide Part 1 Flashcards
Body fluid distribution: Intracellular: Extracellular - Cardiovascular/plasma: - Interstitial/tissue fluid:
Body fluid distrubution: Intracellular (cytoplasm): 67% Extracellular: 33% - Cardiovascular/plasma: (33% * .2) - Interstitial/tissue fluid: (33% * .8)
Extracellular matrix:
- Composition:
- Functional Interactions:
COMPOSITION:
Structural proteins:
- Elastin
- Collagen (including Collagen IV)
Ground Substance:
- proteoglycans and glycoproteins (predominately polysaccharides)
FUNCTIONAL INTERACTIONS:
- Ground substance glycoproteins and proteoglycans form complex structure, and chemically bond structural proteins)
- Bind ligands and other signal molecules and help to deliver them to integrins and other surface proteins.
Collagen type IV:
- Location
- Interactions
- Location:
Basal Lamina underlying epithelial cells - Interactions
Bonds with carbohydrates in the plasma membrane of epithelial cells
Bonds with the glycoproteins of the matrix of connective tissues
Integrins:
- What they are:
- Location:
- Function:
- What they are:
Glycoproteins - Location:
Extend from the cytoplasm, through the plasma membrane and into the extracellular matrix - Function:
Impart a polarity to the cell (it can locate basal side)
integrate communication between cytoplasm and interstitial zones.
Affect movement (by disconnecting) and affect replication of cells
Diffusion/Protein mediated and otherwise: Carrier mediated diffusion: Non-Carrier mediated diffusion: Passive transport: Active transport:
Carrier mediated diffusion: - Facilitated diffusion - Active Transport Non-Carrier mediated diffusion: - Simple diffusion (non-carrier mediated) of nonpolar a/o small lipid soluble molecules - Channel mediated diffusion of ions - Simple diffusion of water (osmosis) through aquaporins Passive transport: - All channel transport - facilitated diffusion (carrier mediated diffusion) Active transport: - All pump based systems
Difference between net diffusion and diffusion:
Net diffusion requires a concentration gradient/difference. It will have directionality.
Diffusion always occurs and doesn’t have to result in a change in conc.
What can diffuse through the plasma membrane?
Non-polar molecules: oxygen, steroids
Small, polar but non-charged molecules: CO2, ethanol, urea
What dictates the rate of diffusion?
1, Magnitude/steepness of Conc. Difference
- Increased magnitude increases the diffusion (likely proportionally)
2, Permeability of ion to diffusing substance
- No permeability means no diffusion period. Increased permeability results in increased diffusion.
3, Temperature (which is harder to change)
- Increased temperature results in increased diffusion.
4, Surface area
- Increased surface area results in increased diffusion. Example microvillid
What is the difference in permeability between Na and K in the membrane?
The membrane is 20 times as permeable to K+ then to Na+.
Two solutions exist (both 1 liter), solution 1: 180 g/L of glucose, solution 2: 360 g/L of glucose
- Membrane is permeable to glucose but not water:
- Membrane is permeable to water but not glucose:
- Membrane is permeable to glucose but not water:
Glucose diffuses until both solutions are homogenous 270 g/L - Membrane is permeable to water but not glucose:
Water diffuses (osmosis) until both solutions are homogenous 270 g/L`
How is the presence of aquaporins in the membrane controlled?
Where are examples of this control?
Vessicles of aquaporins are pulled into the cell, or put back into the plasma membrane from the cytoplasm
Kidney, salivary gland, brain, eyes, lungs.
Osmotic pressure:
- Describe it:
- What cells tolerate it well and which poorly?
- Describe it:
The pressure required to resist the flow of osmosis if a physical container was stopping expansion from it. - What cells tolerate it well and which poorly?
Animal cells would lyse in hypotonic conditions.
Plant cells survive under high osmotic pressure conditions because of rigid cellulose based cell walls.
Difference molality and molarity:
Molal: 1 mole of substance is dissolved in 1 kg of water (more than a liter, but always exactly the same amount of water)
Molar: 1 mole of substance has water added until it is exactly 1 liter of fluid and substance (exactly a liter of total solution, varying amounts of water)
Osmolality:
A measure of the total molality of all different solutes in the solution ( .2 osm solution could be .15 m gluc and .05 Na+)
Osmolality vs tonicity:
Tonicity is a measure of the osmotic action of water in the solution. If two solutions are isoosmotic it means they have the same ratio of moles of molecules to kg of water. It does not mean that they have the same ratio of osmotically active molecules.
Isotonic solutions will have no flow of water, isoosmotic solutions may, depending on permeability.
What is used as a proxy measurement of osmolality and why does it work?
Freezing point depression.
It works because both freezing point depression and osmolality is affected only by the number of molecules in the solution and not their chemical properties.
Crenation:
Hemolysis:
Crenation: Cell shrivels in a hypertonic solution
Hemolysis: RBC lysis in a hypotonic solution (cytolysis is the generic term)
Which cell type is most vulnerable to changes in osmolality?
How much does osmolality usually change in the body?
Neurons
1-3% (3 - 9 mOsm)
Osmoreceptors:
- Location:
- Mode of activation:
- Results of activation:
- Location:
Hypothalamus - Mode of activation:
Hypertonic interstitial fluid will crenate osmoreceptors. This mechanically stimulates/activates receptors. - Results of activation:
Stimulates the urge to drink
Activates a tract of axons which lead to release of ADH/vasopressin which causes decreased water content in the urine
Salt and water homeostasis:
- Effect of high salt diet:
- Effect of low salt diet:
- Effect of high salt diet:
Increased blood osmolality, dehydration and mechanical activation of osmoreceptors in the hypothalamus. Increased desire to drink. Stimulation of axons which promote increased release of ADH/vasopressin resulting in increased water retention by kidneys (less water in urine).
Will dilute salt in plasma by adding water, increasing blood pressure (due to increased fluid). - Effect of low salt diet:
Decreased blood osmolality, expansion and deactivation of osmoreceptors in the hypothalamus. Decreased desire to drink. Less stimulation of axons resulting in decreased release of ADH/vasopressin resulting in decreased water retention by kidneys (more water in urine).
Will return osmosis by releasing water from the body. Results in low blood pressure and a loss of fluids from body. (this can be fatal)
Three traits shared between carrier proteins and enzymes:
Specificity: Only specific molecules can fit.
- Glucose carriers cannot transport closely related monosaccharides
- Amino acid carriers can transport certain types of amino acids but not others
- Amino acids which use the same transporter compete (more of competition)
Saturation:
- Limited capacity, can only process so many at a time.
- Maxed at the Tm (transport maximum)
Competition:
- Molecules which use the same forms of carries can saturate the enzyme together
- Molecules which use the same forms of carriers slow the rate at which each other diffuse.
Facilitated diffusion:
- Powered by:
- Powered by:
Brownian motion, and involves net diffusion
(Carrier protein mediated)
GLUT1: GLUT2: GLUT3: GLUT4: GLUT5: SGLUT1:
GLUT1: In the RBCs and the brain
GLUT2: Present in the liver, pancreatic beta-cells, lateral border of the small intestine, kidney
GLUT3: Present mainly in the brain
GLUT4: Muscles (skeletal and cardiac) and the adipose tissue
GLUT5: Small intestine for sugar absorption
SGLUT1: Small intestine and kidney