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physiology > chp 6 > Flashcards

chp 6 Flashcards

1
Q

extracellular matrix contains ____

A

integrins

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2
Q

what are integrins?

A

class of glycoproteins, that extend from the cytoskeleton within a cell through plasma membrane, into the cellular matrix

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3
Q

What do integrins do?

A

serve as adhesion molecules between cells and extracellular matrix. They act as relay signals between the intracellular and extracellular components

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4
Q

functions of integrins are?

A

impart a polarity onto the cell
affect ability of cell motility
affect ability of cells to proliferate in tissues
affect cell adhesion in their tissues

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5
Q

what are the two types of carrier-mediated transport?

A

facilitated diffusion and active transport

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6
Q

Three types of non-carrier mediated transport

A

simple diffusion of lipids, simple diffusion of ions, osmosis

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7
Q

simple diffusion of lipids are:

A

molecules through phospholipid bilayers of plasma membrane

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8
Q

simple diffusion of ions ?

A

across plasma membrane through channel proteins

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9
Q

osmosis is?

A

diffusion of water molecules through aquaporin channels in plasma membrane

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10
Q

passive transport

A

-is the net movement of molecules/ions from HIGH to LOW concentration.
-no ATP or energy required
-all types of non-carrier mediated transport fall under passive transport

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11
Q

Active transport is what type of transport?

A

carried-mediated transport

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12
Q

net movement of molecules/ions from LOW to HIGH concentration against a concentration gradient
-atp/energy is required

A

active transport

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13
Q

what type of transport is facilitated diffusion?

A

carried-mediated transport

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14
Q

-Glucose or organic molecule binds to site on specific carrier protein.
-Carrier protein undergoes conformational change to release molecule on other side of membrane
-if the organic molecule in questions concentration INCREASED outside if the cell, this would INCREASE of facilitated diffusion

A

facilitated diffusion

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15
Q

Net diffusion is?

A

to have a concentration difference , the aim is to equalize the concentration of both regions

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16
Q

Diffusion through the PM

A

-concentrations from HIGH to LOW
-nonpolar molecules and small but uncharged molecules with polar covalent bonds can diffuse across plasma membrane
-oxygen concentration is high in extracellular fluid
-gas exchange by diffusion occurs in the lungs
-concentration gradient for O: high (air) to low (blood)
-concentration gradient for CO2: high (blood)to low (air)

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17
Q

ion channels

A

these proteins allow charged ions to be transported but are selective in which ones they allow

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18
Q

ion channels can always be ______

A

gated so require a certain stimulus to open an closed channel.

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19
Q

rate of diffusion depends on:

A
  1. Magnitude of concentration difference across membrane
  2. Permeability of membrane to diffusing substances
  3. Temperature of solution
  4. Surface area of membrane through which substances are diffusing
20
Q

osmosis has 2 requirements to occur:

A
  1. membrane must be selectively permeable to solute
  2. difference in solute concentration on two sides of the membrane
21
Q

what is osmotic pressure?

A

pressure needed to stop osmosis from occurring. The greater the solute concentration of a solution, the greater its osmotic pressure

22
Q

measuring osmolality

A

measure of total concentration of a solution

23
Q

tonicity is ?

A

describes the effect of solution on osmotic movement of water

24
Q

isosmotic?

A

having the same osmolality

25
Q

hypotonic is?

A

cells enlarge/burst water goes in volume increases

26
Q

hypertonic is?

A

cells shrink bc water leaves

27
Q

common characteristics between enzymes and carrier proteins:

A

specificity, competition, satuaration

28
Q

transport maximum?

A

Maximum rate at which a substance can be transported by carrier protein across a plasma membrane. Transport maximum is related to saturation

29
Q

occurs when hydrolysis of ATP is directly responsible for the function of the carriers.

A

primary active transport

30
Q

Ca2+pump

A

-Carrier protein transports Ca2+ from a lower concentration side inside the cell to a higher concentration, outside the cell
-1Ca2+ within the cell binds to a site in the carrier protein
2) ATP is hydrolyzed into ADP and phosphate (Pi), which are bound to the pump;
phosphate is added to carrier protein
3) Both exits for Ca2+ are blocked momentarily, release of ADP leads to phosphorylation…
-Phosphorylation causes “hinge-like” motion of carrier
4) Hinge-like motion of protein carrier allows Ca2+ to be released in the extracellular fluid

31
Q

Na+/K+ pump

A

Three Na+ ions in cytoplasm move partway into pump + bind to 3 amino-acid sites
2) ATPase is activated; ATP is hydrolyzed into ADP and Pi, momentarily blocking both exits
(as in Ca2+ pump)
3) ADP is released, inducing a conformational change to open a “passage” for the 3 Na+
ions to exit into the extracellular fluid
4) Two K+ ions bind to the carrier, releasing Pi
5) Release of Pi makes pump return to initial state + release 2 K+ ions back into cytoplasm
K+ is higher concentration in cytoplasm than extracellular fluid Na+ is higher concentration in extracellular fluid than cytoplasm

32
Q

Secondary active transport

A

-In conjunction to one another; Na+ is transported against its’ concentration gradient, from low to high concentration (as in Na+/K+ pump) to transport ANOTHER molecule or ion DOWN its’ concentration gradient (this mol/ion is going from high concentration to low concentration)
-Cotransport/Symport: Both Na+ and molecule move in the same direction (into/out of the cell) -Countertransport/antiport: Na+ and molecule move in opposite direction (one is in/out; other is out/in)
**REQUIRES SODIUM IONS
Eg; cotransport of Na+ and glucose:
-SGLT2 (carrier protein) transports Na+ and glucose at the same time, moving from kidney tubules to epithelial cell lining
-Lower intracellular concentration of Na+ is required
**Depends on Na+/K+ pump, which depends on ATP
**co-transport indirectly depends on ATP
**Na+ will move down its’ concentration gradient
**Glucose will move up its’ concentration gradient
-Secondary active transport depends on primary active transport

33
Q

membrane potential

A

-Na+/K+ pumps move three Na+ ions into the extracellular fluid ( against the concentration gradient)
-Na+/K+ pumps move two K+ ions into the cytoplasm ( against the concentration gradient) -ATP Pi groups + organic molecules are negatively charged (anions) at pH of the cytoplasm -Anions are fixed within cell membrane, attract cations (K+, Na+, Ca2+, etc)
-Plasma membrane is most permeable to K+ ion
-This attraction leads to an unequal distribution of cations between intracellular and extracellular component

34
Q

potential difference

A

cells are negative charge on the inside of plasma membrane and positive charge outside

35
Q

equilibrium potentials

A

Membrane potential (measure of how much an ion contributes to potential difference) depends on:
A) Concentrationgradient
B) Membranepermeability
-Membrane potential is primarily determined by the K+ concentration gradient
-K+ Equilibrium potential: Constant movement of K+ in and out of the cell(s) because of electrostatic attraction to anions till a particular value is reached for inside (higher concentration of K+ ions) and outside (lower concentration of K+ ions)
-The amount that goes = the amount that goes out (net diffusion)
-Value of Ek (K+ equilibrium potential) = -90mV
** >-90mv ; More K+ into the cell
** <-90mV; More K+ diffuses out of the cell
-Na+ Equilibrium potential: >+66mV; more Na+ into the cell<+66mV; more Na+ diffuses out of the cell

36
Q

the three types of cell signaling are:

A

paracrine, endocrine, and synaptic signaling

37
Q

paracrine signaling is?

A

Cells in an organ secrete a regulatory molecule.This molecule will travel through an extracellular matrix to nearby target cells.

38
Q

autocrine signaling is?

A

regulatory molecules released by autocrine cells act on same cells

39
Q

synaptic signaling is?

A

Axon of neuron innervates target cell; synapse between the axon
ending and target cell. A cleft is present between the two cells and neurotransmitters are released by the axon endings.

40
Q

endocrine signaling is?

A

endocrine glands secrete hormones into the extracellular fluid

41
Q

cells must have specific receptor proteins to respond to any of the above signaling types

A

true

42
Q

IF regulator cell is NONPOLAR = Diffuses through plasma membrane and enters cell
IF regulatorcell is polar = Attaches to receptor on surface of plasma membrane
NONPOLAR ; No need for second messengers (“mediators” for regulator cell)
POLAR; Need for second messengers

A

true

43
Q

second messengers are?

A

Mediator of the regulatory molecule
-Second messengers concentration ↑ by regulator cell’s attachment to receptor
-Second messengers stimulate metabolism in target cell in a SIMILAR manner of regulator cell -Eg; cAMP (cyclic-AMP):
A) Polarregulatormoleculebindstoits’receptoronsurfaceofplasmamembrane
B) IndirectactivationofenzymethatproducescAMPfromATPprecursorincytoplasm C) cAMP concentration ↑ , activating inactive enzymes in cytoplasm
D) Enzyme activated by cAMP alter cell activities to produce effect of regulator molecule

44
Q

G-proteins are:

A

Alpha, beta, and gamma subunits

45
Q

G-proteins are:

A

-Activates the enzyme (indirectly) when regulator molecule binds to receptor protein -When regulator molecule binds to receptor protein;
A) Alpha subunit dissociates from Beta-Gamma subunit
B) Alpha subunit releases GDP+binds to GTP
C) Alpha subunit moves through cell and binds to enzyme (temporary activation)
D) Alpha subunit hydrolyzes GTP into GDP and Pi, 3 subunits reassemble and return to
receptor protein

physiology (10 decks)

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