Test 1 Study Guide Part 1 Flashcards

1
Q
Body fluid distribution:
Intracellular:
Extracellular
- Cardiovascular/plasma:
- Interstitial/tissue fluid:
A
Body fluid distrubution:
Intracellular (cytoplasm): 67%
Extracellular: 33%
- Cardiovascular/plasma: (33% * .2)
- Interstitial/tissue fluid: (33% * .8)
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2
Q

Extracellular matrix:

  • Composition:
  • Functional Interactions:
A

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.

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3
Q

Collagen type IV:

  • Location
  • Interactions
A
  • 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
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4
Q

Integrins:

  • What they are:
  • Location:
  • Function:
A
  • 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
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5
Q
Diffusion/Protein mediated and otherwise:
Carrier mediated diffusion:
Non-Carrier mediated diffusion:
Passive transport:
Active transport:
A
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
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6
Q

Difference between net diffusion and diffusion:

A

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.

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7
Q

What can diffuse through the plasma membrane?

A

Non-polar molecules: oxygen, steroids

Small, polar but non-charged molecules: CO2, ethanol, urea

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8
Q

What dictates the rate of diffusion?

A

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

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9
Q

What is the difference in permeability between Na and K in the membrane?

A

The membrane is 20 times as permeable to K+ then to Na+.

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10
Q

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:
A
  • 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`
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11
Q

How is the presence of aquaporins in the membrane controlled?
Where are examples of this control?

A

Vessicles of aquaporins are pulled into the cell, or put back into the plasma membrane from the cytoplasm
Kidney, salivary gland, brain, eyes, lungs.

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12
Q

Osmotic pressure:

  • Describe it:
  • What cells tolerate it well and which poorly?
A
  • 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.
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13
Q

Difference molality and molarity:

A

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)

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14
Q

Osmolality:

A

A measure of the total molality of all different solutes in the solution ( .2 osm solution could be .15 m gluc and .05 Na+)

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15
Q

Osmolality vs tonicity:

A

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.

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16
Q

What is used as a proxy measurement of osmolality and why does it work?

A

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.

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17
Q

Crenation:
Hemolysis:

A

Crenation: Cell shrivels in a hypertonic solution
Hemolysis: RBC lysis in a hypotonic solution (cytolysis is the generic term)

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18
Q

Which cell type is most vulnerable to changes in osmolality?

How much does osmolality usually change in the body?

A

Neurons

1-3% (3 - 9 mOsm)

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19
Q

Osmoreceptors:

  • Location:
  • Mode of activation:
  • Results of activation:
A
  • 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
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20
Q

Salt and water homeostasis:

  • Effect of high salt diet:
  • Effect of low salt diet:
A
  • 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)
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21
Q

Three traits shared between carrier proteins and enzymes:

A

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.

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22
Q

Facilitated diffusion:

- Powered by:

A
  • Powered by:
    Brownian motion, and involves net diffusion
    (Carrier protein mediated)
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23
Q
GLUT1:
GLUT2:
GLUT3:
GLUT4:
GLUT5:
SGLUT1:
A

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

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24
Q

GLUT4:

  • Location:
  • Regulation:
A
  • Location:
    Skeletal and cardiac muscle and the adipose tissue
  • Regulation:
    Stored in vesicles inside the cytoplasm.
    Brough out of storage by insulin and exercise
25
Q

Fatty acid transport into the cell.

A

Occurs via facilitated diffusion of fatty acids.

This is also regulated by insulin and exercise

26
Q

Where is an example of active transport:

A

SGLUT1 (I suspect but do not know) actively transports glucose from the kidney’s tubules

27
Q

Ca2+ Pump:

  • Cell types:
  • Location in cells:
  • How it works:
A
  • Cell types:
    All cells
  • Location in cells:
    Found in the endoplasmic reticulum (cisternia) and plasma membrane
  • How it works:
    Binding of Ca2+ (intracellular) to the inside of the pump)
    ATP is hydrolyzed to ADP and Pi (both exits currently blocked)
    ADP detaches and the pump opens to the outside of the cell
    Ca2+ is released
    Pi is released and the pump returns to its normal conformation
28
Q

Na+/K+ Pump:

  • Frequency of activity
  • Cell types:
  • Location in cells:
  • How it works:
A
  • Frequency of activity
    Always active
  • Cell types:
    All cell types
  • Location in cells:
    Plasma membrane
  • How it works:
    Three Na+ bind to the pump
    (ATP -> ADP + Pi) both exits are temporarily blocked
    ADP is released, Na+ diffuses outward and 2 K+ attach to the receptor
    Pi detaches the receptor returns to its normal state, and K+ diffuses into the cytoplasm
29
Q

What are the functions of the Na+/K+ gradient:

A
  • Provide energy basis for secondary active transport
  • Provide Na+/K+ difference for nerve cell firing
  • Expulsion of Na+ stops inflow of water through osmosis, which could damage cells
30
Q

Cotransport/symport:

  • Description:
  • Example:
A
  • Description:
    Molecules flow in the same direction (one down its conc. gradient, the other against it)
  • Example:
    Cotransport of Na+ and glucose in the kidney (1 to 1 ratio) and small intestine (2 to 1 ratio of Na to glucose)
31
Q

Countertransport/Antiport

  • Description:
  • Example:
A
  • Description:
    Molecules flow in the different directions (one down its conc. gradient, the other against it)
  • Example:
    Na+ / Ca2+ counter exchanger in cardiac cells brings in Na+ to remove Ca2+
32
Q

Na+ Glucose contransporter:

- How it works:

A
  • How it works:
    Na+ binds to its negative binding site
    Binding of sodium allows glucose to bind.
    Conformational change transfers glucose and Na into the cell
    After release the carrier returns to its normal formation
33
Q

Digitalis:

  • Mechanism of Action:
  • Use in treatment of congestive heart failure:
A
  • Mechanism of Action:
    Inactivates Na+/K+ pumps
  • Use in treatment of congestive heart failure:
    Inactivation of Na+/K+ pumps leads to decrease in extracellular Na+ levels fall (or Na+ levels inside rise, either way decreased gradient)
    This results in decreased use of the Na+/Ca2+ exchanger and increased intracellular Ca2+
    This leads to stronger contraction of the heart.
    Improves blood flow and reduces congestion in the heart and lungs
34
Q

Endocytosis (a type of bulk transport):

  • Receptor mediated:
  • Possible end destinations:
A
- Receptor mediated:
This form of endocytosis requires binding of molecules to receptors before endocytosis. This enables localization of a desired protein or other molecule (such as cholesterol)
- Possible end destinations:
Vesicles (for reintroduction later)
Lysosome
35
Q

Exocytosis (a type of bulk transport):

- Examples of exocytosed materials:

A
  • Examples of exocytosed materials:

Expulsion of hormones or neurotransmitters

36
Q

Factors which cause the membrane potential:

A
Na+/K+ pumps:
Fixed anions within the cell:
- Proteins, Cl-, Phosphates on ATP
Increased cellular permeability to K+:
Electrogenic effect:
37
Q

Na+ Conc Intracellular vs extra

K+ Conc Intracellular vs extra

A

12 mEq/L to 150 mEq/L

5 mEq/L to 150 mEq/L

38
Q

What determines how much an individual ion contributes to the membrane potential:

A
  • Their conc. difference

- How permeable the membrane is to them.

39
Q

Change to which ions extracellular conc. will most greatly impact the cell?

A

Increased levels of K+ outside of the cell will remove its conc. gradient, and as it is the most permeable lethal injections of KCl kill by depolarizing heart cells by stoping this diffusion.

40
Q

Potential of membrane permeable predominately to K+ (resting membrane potential):
Potential of membrane permeable predominately to Na+:

A

-65 mV to -85 mV

+30 mV

41
Q

Why does some K+ leak out of the cell?

A

Because the resting membrane potential is more positive then the K+ equilibrium potential (potassium wants to leave, but it keeps getting pumped back in)

42
Q

Three types of cell signalling categories (barring gap-junctions)

A

Paracrine:
Synaptic:
Endocrine:

43
Q

Paracrine:

  • Range:
  • Function:
A
  • Range:
    Stays in one organ
  • Function:
    Involved with growth regulation and coordination of activities within an organ
44
Q

Innervate define:

A

Synapse with

45
Q

Endocrine Signalling:

  • Define:
  • Specificity/Receptors:
A
  • Define:
    Signaling by diffusible hormone.
  • Specificity/Receptors:
    To respond to a hormone the correct receptor must be present
    Estimated to be 30,000 types of receptors (with each cell having several million total receptors)
  • Nonpolar hormone ligands:
    Will have a intracellular receptor.
46
Q

Nonpolar hormone ligands:

  • Names:
  • Receptor location:
A
  • Names:
    NO, steroid hormones, thyroid hormones
  • Receptor location:
    Will have a intracellular receptor.
47
Q

Large/polar hormone ligands:

  • Names:
  • Receptor location:
A
  • Names:
    Epinephrine, Insulin, Acetylcholine
  • Receptor location:
    Plasma membrane
48
Q

Second Messengers:

- Common types:

A
  • Common types: cAMP, Ca2+
49
Q

cAMP:

- Steps for pathway

A
  • Steps for pathway
    Binding of polar molecule to external receptor.
    Indirectly activates an enzyme which produces cAMP from ATP
    cAMP activates proteins in cytoplasm
    Proteins/enzymes activated change the cells response
50
Q

G-Proteins:

- How do they work:

A
  • How do they work:
    Alpha-Beta-Gamma are all coupled together with GDP
    Find a G-protein coupled receptor with ligand bound. alpha subunit releases GDP and GTP is bound (GTP serves as a ‘timer’ until it is phosphorylated and reassembly occurs)
    Alpha wonders off with GTP and Beta-Gamma can also wander off activating effector proteins (CHANNEL OR ENZYME)
    Alpha eventually autophosphorylates its GTP, which causes reaggregation of the complex and an end to stimulation of the downstream effector
51
Q

What are the possible downstream effectors of G-proteins, give an example of each.

A

Enzyme, as with the enzyme which produces cAMP activated by Epinephrine or Norepinephrine
Channel, such as Ca2+ channels opened by Acetylcholine causing the heart to slow

52
Q

What is the point of G-proteins? Illustrate this point?

A

The point is flexibility.
An illustration of this is that 400-500 different G-protein coupled receptors to regulatory molecules and 100-200 for smell and taste.

53
Q

What is the driving force for diffusion and osmosis?

A

The random molecular motion of water/brownian motion

54
Q

What is the osmolality of human plasma:

  • Grams of glucose into 100 ml
  • Grams of NaCl into 100 ml
A
- Grams of glucose into 100 ml
5 grams (5% glucose solution)
- Grams of NaCl into 100 ml
.85 grams (.85% NaCl (saline))
55
Q

ADH has what effect on the kidney tubules?

A

It increases the number of aquaporins

56
Q

Penicillin and probenecid competition:

A

Penicillin is excreted in the urine by carrier protein in the kidney tubules.
probenecid also uses these carrier proteins. Competition lowers the amount of penicillin lost by carrier proteins in the kidney.

57
Q

Hypokalemic Periodic Paralysis:

A

Recurrent episodes of skeletal muscle weakness.

Low K+ levels in plasma

58
Q

Gap junction components:

A

gap junction = 2 connexons

Connexon = 6 connexins