VME 7136 Phys/Histo > Physiology 2 > Flashcards

Physiology 2 Flashcards

membrane transport (52 cards)

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1
Q

Diffusion through the lipid bilayer depends on the ______ of the molecule being diffused. Which type of molecule(s) easily get diffused?

A

hydrophobicity

1) lipid-soluble molecules
2) small, polar molecules

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2
Q

Because of the hydrophobic interior, cell membrane prevents the passes of ____ and ____ molecules through simple diffusion. How can we get these molecules into the cell?

A

polar
charged

specialized transmembrane proteins

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3
Q

Osmolality describes…

A

the number of osmotically active solutes in a solution

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4
Q

What are the 3 classifications of osmolality? How do we differentiate?

A

1) isosmolal (=290 mOsm)
2) hyperosmolal (>290 mOsm)
3) hypoosmolal (<290 mOsm)

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5
Q

What is the reference solution when it comes to osmolality?

A

ICF (intracellular fluid)

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6
Q

What does it mean when a solution is isotonic? Hypertonic? Hypotonic?

A

iso
-osmolality same as ICF

hyper
-osmolality higher then ICF

hypo
-osmolality lower than ICF

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7
Q

Osmosis is…

A

the diffusion of water

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8
Q

Water will diffuse from the region of ______ concentrated solution to ______ concentrated solution.

A

lower
higher

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9
Q

If a cell is placed in a hypertonic solution, what happens? Why?

A

water moves out of the cell and leads to cell shrinkage

solution has higher concentration (osmolality) than ICF of cell

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10
Q

If a cell is placed in a hypotonic solution, what happens? Why?

A

water moves into the cell and leads to cell swelling

solution has lower concentration (osmolality) than ICF of cell

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11
Q

If a cell is placed in an isotonic solution, what happens? Why?

A

nothing. cell shape is maintained

concentration of solution and ICF are equal

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12
Q

Loss of body fluids due to dehydration can be maintained by infusing _____solutions like 0.9%NaCl. Why?

A

isotonic

it matches the body’s composition

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13
Q

If a patient has hypernatremia, or elevated Na+ in blood, which type of solution should you infuse?

A

hypotonic (lessens concentration)

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14
Q

If a patient has acute shock from blood loss, which type of solution should you infise?

A

hypertonic (pulls water from body and increases blood volume)

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15
Q

Cells can recover from shrinkage by opening ___ and ______ intake channels. How does this help?

A

Sodium (Na)
Chloride (Cl)

increase in concentration leads to water pulling from outside cell

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16
Q

Cells can recover from cell expansion by opening ___ and ______ release channels. How does this help?

A

Potassium (K)
Chloride (Cl)

water will follow pumped out molecules to keep concentration balanced

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17
Q

What are aquaporins? What type of gland uses aquaporins and what do they produce?

A

specialized hydrophilic transmembrane channels for the passage of water

exocrine
-sweat
-saliva
-tears

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18
Q

The net passive movement of a charged solute across the membrane depends on the difference in ______ and ________ between ECM and ICF. What is the name of the location of charged ion movement?

A

concentration
voltage

electrochemical gradient

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19
Q

Solutes can be transported across the membrane ______ or _______. What are they dependent on?

A

passively - concentration

actively - energy

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20
Q

______ ________ is passive down the concentration gradient. Does it require ATP?

A

Simple Diffusion

NO

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21
Q

_______ ______ ______ uses a carrier protein to facilitate transport down a gradient. Does it require ATP?

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A

facilitated passive diffusion

NO

22
Q

Transmembrane proteins allow transfer of ____ molecules across membrane. They lower the _______ ______ and increase rate of movement across membrane

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A

polar

activation energy

23
Q

What are the 3 main differences between ion channels and transporters/pumps?

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A

1) ion channels have greater rate of movement
2) channels are with gradient, transporters are against gradient
3) ion channels have a single gate, transporters have 2

24
Q

______ are the specialized receptors that mediate glucose transport w/ concentration gradient. Which disease messes with these transporters?

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A

GLUT’s

diabetes

25
Transports differ in number of ______ and direction in which the solute moves. What are the 3 different combinations?
solutes 1) uniport w/ single solute 2) symport w/ 2 solutes in same direction 3) antiport w/ 2 solutes in opposite directions
26
What is an example of an antiport?
chloride-bicarbonate exchanger lose bicarbonate intake chloride
27
Which type of transport requires ATP? Why?
active transport movement against concentration/gradient
28
What is an example of active transport? Why is it important?
sodium-potassium pump keeps the cytosol sodium low and potassium high (3 Na+ out and 2 K- in)
29
What are the 2 types of active transport? What are the main differences?
1) primary active -ATP hydrolysis drives solute against gradient 2) secondary active -gradient provides energy to move second solute against gradient
30
p-ATPase catalyzes which pump?
Na-K
31
v-ATPase catalyzes what exchange?
H+ into stomach contents, making acidic
32
f-ATPase synthesize _____ by transporting H+ down gradient
ATP
33
ABC transporters, such as _____ _______ ______, transport drugs out of the cell by utilizing what 2 things?
multidrug resistance transporters (MDR1) ATP nucleoside binding domains (NBD)
34
_____ ______ channels couple with NaK ATPase to determine a plasma membrane's permeability to...
K leak specific ions and to keep concentration of ions and membrane potential
35
What are the 3 subtypes of ion-gated channels?
1) voltage-gates 2) ligan-gated 3) mechanical gated
36
What happens with voltage-gated ion channels? What are some examples?
change in transmembrane electrical potential causes a charged protein domain to move in membrane, opening/closing channel K channel, Ca channel, Na channel
37
What are the 3 conformational stages you'll typically find a voltage-gated channel in?
1) closed 2) open 3) inactivated
38
What happens in a ligan-gated ion channel?
an extracellular or intracellular molecules binds to the protein and causes an allosteric transition, opening/closing the channel
39
Voltage-gated ion channels are very selective for which cation?
Na+
40
The ________ receptor allows Na, Ca2, and K to pass through channel ease vs other cation/anions
acetylcholine
41
Which 2 receptors are anion channels specifically for Cl-?
1) GABA 2) glycine
42
What is endocytosis?
vesicular-dependent uptake
43
What is phagocytosis?
engulfment of foreign pathogens
44
What is pinocytosis?
cell drinking
45
What is transcytosis?
compoartment to compartment
46
Drug absorption is directly proportional to ____ and _____ ______, and inversely proportional to ________ of the membrane
area concentration gradient thickness
47
What 2 drugs are more easily absorbed? Which 2 are not as easily absorbed?
1) lipophilic 2) unionized 1) hydrophilic 2) ionized
48
Most drugs are developed as ______ of weak bases/acids. Why?
salts good solubility and absorption
49
What is pKa?
pH when the drug is 50% ionized and 50% unionized
50
Is a strong or weak acid easily absorbed in an acidic environment? Why?
weak least ionized
51
Is a strong or weak base easily absorbed in an acidic environment? Why?
strong least ionized
52
To assist excretion of acidic drugs via urine, which type of environment is favored?
alkaline
VME 7136 Phys/Histo
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