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KP222 > Quiz #1 > Flashcards

Quiz #1 Flashcards

1
Q

What are the levels of organization in the body?

A 
cell
tissue
organ
organ system
organism
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2
Q

What are the 4 major cell groups/tissue types?

A

neurons/nerve
muscle
epithelial
connective

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3
Q

What is homeostasis?

A

the ability to maintain a relatively constant internal environment that is the basis for all physiological function

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4
Q

What are the main components of the negative feedback system for homeostasis?

A

receptors
- sensitive to change in physiology

afferent nerve

control/integrating centre
- receives info from receptors and interprets it

efferent nerve

effectors
- receives signals from control centre and causes response that returns physiological variable to set point

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5
Q

What are the 3 stages of signal transduction?

A

reception
- signalling molecule and receptor fit like lock and key, cause transduction

transduction
- molecules/proteins expressed cause a signal transduction pathway leading to a response

response
- activation of cellular responses

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6
Q

What are tight junctions?

A

found in epithelium
line surface of organs
form a nearly impermeable barrier that keeps cells very tight together
have occludins

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7
Q

What are occludins?

A

integral proteins that fuse adjacent cells

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8
Q

What are desmosomes?

A

in cardiac muscle, bladder, and GI muscosa (muscle tissues that are subject to significant mechanical stress)

filamentous junctions that keep cells tight together for strength

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9
Q

What are gap junctions?

A

made of membrane proteins
link cytosol of 2 adjacent cells for direct, rapid communication
- ions and molecules travel between cells
have connexins

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10
Q

What are connexins?

A

gap junction proteins that span membranes open to create a channel

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11
Q

How do cells communicate over long distances?

A

combo of electrical (nerve cells) and chemical (hormones) signals

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12
Q

What are the 2 types of short distance intracellular communication?

A

direct
- gap junctions

indirect
- chemical messengers released by one cell act on specific receptors of another

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13
Q

What are autocrine signals?

A

signals that act on the same cell that secreted them

used by immune system

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14
Q

What are paracrine signals?

A

signals secreted by one cell that diffuse to and act on an adjacent cell

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15
Q

What is the difference between neurotransmitters and neurohormones?

A

neurotransmitters diffuse across a small gap to the target cell

neurohormones are released into blood for action at distant targets

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16
Q

What is the role of membranes?

A

separate material and allow exchange of material between cellular and intracellular fluid

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17
Q

What is selective permeability?

A

allow certain molecules (small, non-polar) to pass through but restrict others (large, polar, ionic) from entering

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18
Q

What is the difference between passive and active transport?

A

passive:

  • spontaneous, downhill, doesn’t require energy
  • high to low concentration

active

  • non-spontaneous, uphill, requires energy
  • against a concentration gradient
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19
Q

What is the chemical driving force?

A

concentration gradient pushes particles from higher to lower concentration areas

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20
Q

What are the 2 types of ions?

A

cations - positively charged particle

anions - negatively charged particles

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21
Q

What is membrane potential?

A

force caused by unequal distribution of charges across the cell membrane

charge separation acts as a source of energy

measured in millivolts

at rest, inside is more negative than the outside

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22
Q

What principles guide the electrical driving force?

A

opposite charges attract, like charges repel

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23
Q

What does the direction of the electrical driving force depend on?

A

polarity of the cell

charge on the particle

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24
Q

What does the magnitude of the electrical driving force depend on?

A

strength of membrane potential

amount of charge on the particle

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25
Q

What is the electrochemical driving force?

A

sum of electrical and chemical forces

if they act in the same direction:
magnitude is the sum of both
direction is same as both forces

if they act in different directions?
magnitude is the difference between them
direction is that of the stronger force

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26
Q

When will equilibrium potential equal membrane potential? (force = 0)

A

when electrical and chemical force are equal and in opposite directions

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27
Q

What does the Nernst equation find?

A

the equilibrium potential of an ion

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28
Q

What is the lumen?

A

interior cavity of a hollow organ/vessel

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29
Q

What are glands?

A

organs specialized in the synthesis and secretion of a product
formed by epithelial cells

30
Q

What are the 2 types of glands?

A

exocrine

  • secrete a product into a duct leading to the external environment
  • ex. sweat glands

endocrine

  • secrete hormones into the bloodstream
  • ex. pituitary gland
31
Q

What are hormones?

A

chemicals that communicate a message to the cells of the body

32
Q

What is the most diverse tissue type?

A

connective

primary function is to provide support for structures or link them together

ex. bone, blood, fat

33
Q

What is the extracellular matrix?

A

mass of non-cellular material containing a dense meshwork of proteins and other large molecules

34
Q

What is the intracellular fluid? What are its contents?

A

water present in the fluid within cells

2/3 of total body water
many proteins, rich in potassium

35
Q

What is extracellular fluid? What are its contents?

A

water present in fluid outside the cells

1/3 of total body water
sparse proteins, rich in sodium

36
Q

What are the components of the extracellular fluid?

A

plasma
the liquid, non-cellular part of blood
rich in proteins
20% of ECF

interstitial fluid
bathes most cells in the body
proteins are scarce
80% of ECF

37
Q

What are the types of feedback?

A

negative
when the system and regulated variable have an inverse relationship

positive
when the system and regulated variable have a positive relationship
- less common

38
Q

What features determine a molecules permeability in a selectively permeable membrane?

A

size
molecular charge
electrical charge
lipid solubility

39
Q

What is bulk flow?

A

movement of gases/liquids according to pressure gradients

40
Q

What is diffusional equilibrium?

A

when there is an equal concentration of a molecule on both sides of a membrane

no net transfer of molecules

41
Q

What is flux?

A

rate of movement of a given particle over time

as concentration gradient increases, so does net flux

42
Q

What is simple diffusion?

A

doesn’t require either energy or a membrane protein

43
Q

What factors affect simple diffusion?

A 
magnitude of concentration gradient
molecule size/shape
temperature
electrical forces
lipid solubility
thickness of membrane
44
Q

What is facilitated diffusion?

A

passive transport through a carrier

still does not require energy

45
Q

What are the characteristics of a carrier for facilitated diffusion?

A

transmembrane protein
has specific binding sites
binding occurs on one side at a time

46
Q

What factors affect the rate of transport for facilitated diffusion?

A

rate of transport for each carrier
concentration gradient
number of carriers in the membrane

47
Q

Describe the role of the GLUT4 transporter in diabetes.

A

transporter insertion is stimulated by insulin

lack of insulin means less GLUT4 inserted into membrane, less glucose uptake, more glucose in the blood

48
Q

What are the characteristics of channels?

A

transmembrane protein
functions like a pore/passageway
substance specific

49
Q

What are the types of channels?

A

ion channels:
leak
gated
bidirectional

aquaporins

50
Q

What factors affect the rate of transport through channels?

A

transport rate of each channel
number of channels in the membrane
state (open or closed)

51
Q

What are the 3 types of gated channels?

A

ligand
- open time depends on binding of ligands

voltage
- open time depends on voltage difference across the membrane

mechanical
- open time depends on stretch level of a membrane

52
Q

What are carrier proteins?

A

proteins that bind to substrates and carry them between intracellular and extracellular compartments

open only to one side of the membrane at once (different than a channel)

transport molecules too big to travel through channel proteins (ex. glucose)

53
Q

What are the 3 types of carrier proteins?

A

uniport
- transport only one kind of substrate

symport
- move 2+ substrates in the same direction

antiport
- move 2+ substrates in opposite direction

54
Q

What is active transport?

A

requires cell energy to move a molecule against its concentration gradient

55
Q

What is primary active transport?

A

needs ATP directly

ion pumps

56
Q

What is secondary active transport?

A

does not need ATP directly

kinecitc energy from another ion travelling down its gradient drive pump

57
Q

What is the difference between cotransport and countertransport?

A

cotransport = same direction

countertransport = opposite directions

58
Q

What are pumps?

A

membrane protein
functions as a transporter and an enzyme
has specific binding sites
demonstrates saturation

59
Q

Describe the sequence of the Na+/K+ pump.

A

open to inside with affinity for Na+

once 3 Na+ have bound, hydrolysis of ATP releases phosphate group that binds to pump

P-group causes conformational change that flips direction of pump opening to ECF, releases 3 Na+

pump now has affinity for 2 K+, once 2 K+ have bonded, phosphate group dissociates

loss of P-group reverses conformational change, opening back towards ICF

releases 2 K+ into ICF, restarting cycle

60
Q

What is sodium-linked glucose transport?

A

an example of cotransport

when Na+ is bound to transporter, affinity for glucose increases and can bind, causing conformational change, releasing once Na+ dissociates on the inside

Na+ moving down its gradient drives glucose against its gradients

61
Q

What is osmosis?

A

diffusion of water through a membrane in response to solute concentration

water moves to dilute more solute-concentrated side until equilibrium is reached

through aquaporins

62
Q

What is osmolarity?

A

total solute concentration of a solution
solute particles displace water

for molecules that don’t dissociate (ex.Na+):
1 mole solute = 1 osmole in 1L of water

for molecules that do dissociate (ex. NaCl):
1 mole solute = 2 osmole in 1L of water

osmolarity of ICF/ECF is about 300mOsm

accounts for permeating and non-permeating solutes

63
Q

What is the difference between iso-osmotic, hypo-osmotic, and hyperosmotic?

A

iso = same concentration

hypo = solution has lower concentration

hyper = solution has higher concentration

64
Q

What is osmotic pressure?

A

the ability to pull water

directly proportional to solute concentration

more concentration of solute = less concentration of water = more osmotic pressure

65
Q

What is tonicity?

A

water gradient across a membrane caused by impermeable solutes

outside relative to inside

66
Q

What are the 3 modes of tonicity?

A

isotonic = doesn’t alter volume

hypertonic solution = cell shrinks, water leaves

hypotonic solution = cell swells, water enters

67
Q

What are the types of endocytosis?

A

phagocytosis

  • cell extends membrane around matter, once surrounding it forms phagosome in cytosol, fuses with lysosome to breakdown particle, usable components are taken
  • cell eating

pinocytosis

  • plasma membrane develops an indentation, outer edges pinch together to form endosome
  • cell drinking

receptor-mediated transport
- endosome formed, receptor proteins recognize and bind to specific ECF particles, vesicle coated in clathrin forms, clathrin and protein coat are recycled, uncoated vesicle forms with lysosome for breakdown

68
Q

What is exocytosis?

A

different vesicles bud up against cell membrane and release contents into ECF

69
Q

What are the 2 membrane layers?

A

apical
- faces lumen of body cavity

basolateral
- faces internal environment (interstitial fluid)

70
Q

What is transcytosis?

A

for moving even larger molecules (macromolecules)

involves endocytosis and exocytosis

71
Q

Why must exocytosis and endocytosis of a cell be balanced?

A

so the size of the plasma membrane does not change

KP222 (7 decks)

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