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Bio 465 - Physio > Ch 6 - Interactions between Cells and Extracell Environment > Flashcards

Ch 6 - Interactions between Cells and Extracell Environment Flashcards

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1
Q

Where is the interstitial fluid derived from? What does it do?

A
  1. Derived from blood plasma that filters through pores between cells of capillary walls
  2. Delivers nutrients and regulatory molecules to the tissue cells
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2
Q

What % body water is contained in the intracellular compartment/extracellular compartment?

A

67% intracellular

33% extracellular

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3
Q

What consists of protein fibers, collagen and elastin, as well as gel-like ground substance?

A

Extracellular Matrix

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4
Q

What two molecules basically make up the ground substance?

A

glycoproteins

proteoglycans

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5
Q

What are the functions of integrins in the plasma membrane?

A
  • class of glycoprotein
  • extend from cytoskeleton within a cell, through its plasma membrane, and into extracellular matrix
    • glue between cell and extracellular matrix
  • relay signals between the two compartments
  • “assign polarity” - basal and apical side
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6
Q

What are the three types of passive transport across a plasma membrane?

A

Simple Diffusion (Including Osmosis)

Diffusion through protein channels

Facilitated Diffusion

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7
Q

Water is a polar molecule, why is it able to generally diffuse through the plasma membrane?

A

Water’s small size, and lack of a net charge allow it to diffuse to a limited degree.

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8
Q

What “channel” greatly aids the passage of water through the plasma membrane?

A

aquaporins

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9
Q

What disease is caused by a genetic defect involving a particular glycoprotein that forms chlroide channels in the apical membrane of the epithelial cells?

A

Cystic Fibrosis - protein is known as CFTR

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10
Q

What are 4 factors on the rate of diffusion?

A
  1. magnitude of the concentration difference across the membrane
  2. permeability of the membrane
  3. temperature of the solution
  4. surface area of the membrane though which the substances are diffusing
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11
Q

Solutes that cannot freely pass through the membrane can promote the osmotic movement of water and are said to be….

A

osmotically active

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12
Q

What are 2 requirements for osmosis?

A
  1. there must be a difference in the concentration of a solute on the two sides of a selectively permeable membrane
  2. the membrane must be relatively impermeable to the solute
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13
Q

What could a low concentration of plasma proteins result in?

A
  • Edema - excessive accumulation of fluid in the tissues
  • Protein concentration of the plasma is higher thatn interstitial fluid, pulling water from interstitial tissue into capillary blood
    • Albumin is main protein of blood, liver makes it. So if liver stops producing it….edema could happen
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14
Q

What ratio does osmotic pressure depend on?

A

ratio of solute to solvent, not on chemical nature of the solute molecules

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15
Q

How much does 1 mole of solute per liter depress the freezing point by?

A

-1.86 degree C

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16
Q

Plasma freezes at about -.56 C, what is it’s Osm?

A

.56 / 1.86 = .3 Osm, or 300 milliosmolal

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17
Q

What is the term used to describe the effect of a oslution on the osmotic movement of water?

A

tonicity

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18
Q

The expression for the total molality of a solution?

A

Osmolality

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19
Q

What are 2 responses to dehydration from the osmoreceptors?

A
  1. Water leaves the osmoreceptors in the hypothalmus and they shrink. This shrinkage stimulates the osmoreceptors, making the person thirsty…if water is available they drink
  2. Dehydration also excretes lower volumes of urine
    1. increased plasma osmolatity stimulates osmoreceptors in the hypothalamus
    2. Osmoreceptors then stimulate a tract of axons that terminate int eh posterior pituitary; this causes the posterior pituitary to release antidiuretic hormone (ADH) , or vasopressin, into the blood
    3. ADH acts on the kidneys to promote water retention, so that a lower ovlume of more concentrated urine is excreted.
20
Q

ADH is released from what gland? What does it normally act on?

A
  1. Posterior Pituitary
  2. Acts on the kidneys, to retain water
21
Q

What are the 3 common characteristics of enzymes and carrier proteins?

A
  1. Specificity
  2. Competition
  3. Saturation
22
Q

What is diabetes mellitus, caused by?

A

inadequate secretion and/or action of insulin

23
Q

What is glycosuria?

A

A condition where - a hyperglycemic diabetic’s glucose carriers, in the kidney, are over saturated. Typical reabsorption cannot take place and excess glucose is expelled in the urine.

24
Q

Using a GLUT carrier, how can a skeletal or adipose cell increase its uptake of glucose during excerise or insulin stimulation?

A

When excerising or insulin stimulation - GLUT4 proteins attached to a vesicle fuse with the plasma membrane…almost like exocytosis, but nothing is released. This increases the amount of glucose facilitated diffusers along the membrane, allowing the cell to take in more glucose

25
Q

What occurs when the hydrolysis of ATP is directly responsible for the function of the carriers, which are proteins that span the thickness of the membrane?

A

Primary Active transport

26
Q

What are two processes that are signaled by the rapid diffusion of Ca2+ down its concentration gradient?

A
  1. release of neurotransmitters from axon terminals
  2. Muscle contraction
27
Q

What functions do the steep Na/K gradient serve?

A
  1. Steep Na+ gradient is used to provide energy for the coupled transport of other molecules
  2. Gradient for Na and K are used in nerve and muscle cells for electrochemical impluses…(potentials)
  3. active extrustion of Na is important for osmotic reasons; if the pumps stop, the increased Na concentration would promote the osmotic inflow of water, damaging cells
28
Q

Where are the two main places you’ll find the cotransport of Na+ and glucose?

A
  1. lumen of the intestine
  2. kidney tubules
29
Q

In the Na/Glucose secondary transport, which molecule is moving up/down is concentration gradient?

A

The Na+ molecule is moving down its gradient (High -> Low) while Glucose is moving up its gradient (Low –> High)

30
Q

What 3 structures make the junctional complexes between epithelial cells?

A
  1. Tight Junctions - space between two adjoining plasma membranes appears to be occluded and strands of proteins penetrate the plasma membranes to bridge the cytoskeleton actin fibers
  2. Adherens junctions - plasma membranes ofthe two cells come very close together and are “glued” by interactions between proteins that span each membrane and connect to the cytoskeleton of each cell
  3. Desmosomes - plasma membranes of the two cells are “buttoned together” by interactions between particular desmosomal proteins.
31
Q

How is cholesterol removed from the blood?

A

receptor-mediated endocytosis in the liver and through the walls of blood vessels

32
Q

What type of molecules require bulk transport?

A

Polypeptides and Proteins….big stuff

33
Q

Which cation is the most permeable in regards to the plasma membrane?

A

K+

34
Q

Why is K+ found in greater concentration within the cell? What are the intracellular and extra cellular concentrations of K+

A
  • Negatively charged, “fixed anions” - like phosphates of ATP, and proteins are negatively charged. This negative charge pulls in the K+ since it is more permeable to the plasma membrane.
  • Intra = 150 mEq/L and Extra= 5 mEq/L
35
Q

What are some of the physiological processes that the potential difference of cells manages?

A

muscle contraction, heartbeat, generation of nerve impulses.

36
Q

What is the membrane potential that would stabilize the K+ concentration? What is it’s numerical designation and what does that number mean?

A
  1. K+ equilibirum potential, EK
  2. At equilibrium K+ = -90mV. This means that a membrane potential of -90 mV is need to produce an equilibrium in which K+ is 150 mM inside and 5 mM outside the cell.
    1. If the number was more negativeit would draw more K+ in, if the number was more positive it would diffuse more K+ out
37
Q

What is the Na+ equilibrium potential, ENa. What are the intracellular and extracellular concentrations causing this equilibrium?

A
  1. +66mV
  2. 12mM inside the cell and 145 mM outside the cell
38
Q

What would happen the the resting membrane potential of a cell if the Na+/K+ pumps stopped working?

A

There would be a excess build up of positively charged Na+ ions. This build up would make nerve impulses impossible, since the resting membrane potential its dependent on the K+ concentration inside the cell. If excess Na+ ions build up, the resting potential will be even more positive than the normal -70mV, thus causing more K+ to diffuse out of the cell.

39
Q

Hyperkalemia is an increase in plasma [blank]? What does this do?

A
  1. Increase in plasma K+
  2. This causes the concentration of extracellular K+ to increase, thus increasing the intracellular concentration. It reduces membrane potential…cuasing heart problems. Heartbeats can be stopped entirely at 8 mEq/L of K+ in the plasma.
40
Q

What are the 3 general types of cell signaling?

A

Paracrine

Synaptic

Endocrine

41
Q

Which type of cell signaling is considered “local” because cells within the organ secrete regulatory molecules that diffuse through the extracellular matrix to nearby target cells within the same organ?

A

paracrine

42
Q

Which type of cell signaling requires the endocrine glands to secrete hormones into the blood?

A

Endocrine signaling…

43
Q

What are some examples of nonpolar regulatory molecules that interact with intracellular receptor proteins?

A

steroid hormones

thyroid hormones

nitrix oxide gas (paracrine hormone)

44
Q

What are some examples of large, polar molecules that interact with receptor proteins located on the outer surface of the plasma membrane?

A

Insulin

acetylcholine

epinephrine

45
Q

What is cAMP? How does it effect cell activity?

A
  1. Cyclic adenosine monophosphate - second messenger
  2. When a regulatory molecule binds with a plasma membrane receptor protein, cAMP is made from ATP on the intracellular side.
    1. This increase in cAMP activates previously inactive enzymes in the cytoplasm
    2. these enzymes change the cell to produce the action of the regulatory molecule
46
Q

What are the 3 G proteins?

A
  1. Three protein subunits that shuttle between receptors and different membrane effector proteins, including specific enzymes and ion channels.
  2. Alpha, Beta, and Gamma

Bio 465 - Physio (16 decks)

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