Vertebrates 4 - Cell properties Flashcards Preview

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Flashcards in Vertebrates 4 - Cell properties Deck (23)
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Cell membrane function

cell integrity, cell metabolism, cell to cell signalling


Osmolarity of mammalian blood

Total concentration of all solutes. 300 mOsm (mM). Cells often have to actively pump solutes in/out


Electrical properties of cells

All cells have different concentrations inside vs outside, creates resting membrane potential.


Electrochemical gradient

Affected by concentration and electrical field across membrane. Nernst equation for equilibrium of any ion. Eion = 58mv/Z) log([ion]out/[ion]in)


Passive electrical properties of membranes

membranes are like circuits - bilayer like capacitor (ions at both heads) and channels like resistors (few = big resistor - slows current flow). V = IR!


Molecules that Diffuse across membrane

Hydrophobic (steroids), small molecules (O2, CO2, NO)


Molecules that Diffuse through channels

Ions and polar molecules (glucose, amino acids) are repelled by bilayer, therefore need channels


Facilitated diffusion

Specific channels; Transport maximum (Tmax) is the max rate of transport across membrane. Can change with a change in number of channels


Active transport

Also has Tmax. Pumps use ATP. Includes coupled transporter like H/Na antiport (NO ATP)


Reading: Julian Creek Dunnarts fall under which family(?) ?

The metatheria, or marsupials


Reading: What types of animals have cutaneous respiration

Occurs in all, but highest in amphibians. Skin of reptiles and mammals is too thick


Reading: What problems may marsupials encounter with respiration?

Young are born underdeveloped. Thought lungs were not developed enough, but most breathe well as newborns. Dunnarts are exception


Reading: Julian Creek Dunnarts respiration

Significant cutaneous respiration for first several days after birth, lungs are under developed because it is so small (grain of rice).


Reading: What do you need for a good gas exchange surface?

High SA/V, thin wall, blood vessels close to surface, moist surface.


Steps in exocytosis

Priming, docking, and fusion. Regulated by Ca influx


Compare types of endocytosis

working on it…


Cell junctions

Tight: in epithelia, nothing get across; Intermediate: not as tight, but strong for stretching (cardiac muscle intercalated disks); gap: communication


Epithelial transport examples

Ex. fish gills, amphibian skin, intestine, kidney tubule.


Ussing chamber

Glass chamber in which you insert tissue to study what can move across it.


Frog skin

Very organized, lots of tight junctions. Studied with ussing chamber. Studied with radioactive Na, moved inwards but not out. Membrane is somehow asymmetrical


Describe epithelial tissue

Exterior, lumen or mucosal side, and interior or serosal side. Paracellular path not common (tight junctions). Transcellular path (diffusion or facilitated)


How does Na+ enter through epithelium?

First H+/Na+ antiport, then a Na/K pump


Why does cyanide and ouabain block sodium transport in the frog skin Ussing experiment?

CN blocks election transport chain at Cytochrome oxidase 4, and ouabain blocks Na/K pump