Exam 1 Flashcards

1
Q

Physiology is the study of

A

functions of living things

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2
Q

Physiology has two approaches, one with an emphasis on ______ and one with an emphasis on ______

A

on purpose of body process (Why?)
• Explanations are in terms of meeting a bodily need

on mechanism (How?)
•	Explanations are in terms of cause and effect sequences
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3
Q

Physiology is the brother of

A

Anatomy

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4
Q

o Structure-Function relationships of the body include:

A
  • Heart receiving and pumping blood
  • Teeth tearing and grinding food
  • Bones protect vital organs
  • Vessels carrying blood
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5
Q

Levels of organization

A
Chemical
•Molecules composed of atoms
Cellular
•Cells are basic units of life
Tissue (group of cells)
Organ (one or more tissues make up an organ)
Body system (one or more organs make up a body system)
Organism
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6
Q

What are the seven basic cell functions?

A

o Obtain nutrients and oxygen from surrounding environment (Things that do not have nutritional value are things that would not keep you alive on a desert island)
o Perform chemical reactions that provide energy for the cell
o Eliminate carbon dioxide and other wastes to surrounding environment
o Synthesize needed cellular components
oRegulate exchange of materials between cell and its surrounding environment
o Sensing and responding to changes in surrounding environment
o Reproduction
-Exception Nerve cells and muscle cells lose their ability to reproduce early in development

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7
Q

What are the 4 primary types of tissue?

A
  • Muscle tissue
  • Nervous tissue
  • Epithelial tissue
  • Connective tissue
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8
Q

What are the 3 types of muscle tissue and their function?

A
Skeletal muscle
•	Moves the skeleton
Cardiac muscle
•	Pumps blood out of the heart
Smooth muscle
•	Encloses and controls movement of contents through organs
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9
Q

Muscle tissue is specialized for ______ and facilitates ______

A

contracting

movement

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10
Q

Nervous tissue consists of cells specialized for _________

A

initiating and transmitting electrical impulses

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11
Q

Nervous tissue is found in _______(3 places)

A

brain, spinal cord, and nerve cells

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12
Q

Epithelial tissue consists of cells specialized for _______

A

exchanging materials between the cell and its environment

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13
Q

Epithelial tissue connects the body and its organs to ________

A

the environment

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14
Q

Epithelial tissue is organized into two general types of structures:

A
  • Epithelial sheets

* Secretory glands

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15
Q

the purpose of connective tissue?

A

Connects, supports, and anchors various body parts

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16
Q

connective tissue is distinguished by having _________

A

relatively few cells dispersed within an abundance of extracellular materials

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17
Q

three examples of connective tissue:

A
  • Tendons- attach skeletal muscle to bones
  • Bone- supports and protects the body
  • Blood- transports bodily materials
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18
Q

organs generally consist of what?

A

two or more types of tissues that work together to perform a particular function

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19
Q

The stomach consists of four different tissue types. Name them and their function as part of the stomach

A
  • Inside of stomach lined with epithelial tissue
  • Wall of stomach contains smooth muscle
  • Nervous tissue in stomach controls muscle contraction and gland secretion
  • Connective tissue binds all the above tissues together
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20
Q

Body Systems-

A

Groups of organs that perform related functions and interact to accomplish a common activity essential to survival of the whole body

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21
Q

Name the 11 systems of the human body

A
  • Circulatory System
  • Digestive System
  • Respiratory System
  • Urinary System
  • Skeletal System
  • Muscular System
  • Integumentary System (hair, skin, nails)
  • Immune System
  • Nervous System
  • Endocrine System
  • Reproductive System
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22
Q

Homeostasis is the ability to maintain a _________, NOT a ____________

A

relatively stable internal environment

constant internal environment

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23
Q

_________ is essential for survival and function of all cells

A

homeostasis

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24
Q

Each cell contributes to maintenance of a relatively stable internal environment to maintain ________

A

homeostasis

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25
Q

Body cells are contained in a ________ through which life-sustaining exchanges are made

A

watery internal environment

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26
Q

Extracellular fluid (ECF)-

A

Fluid environment in which the cells live (fluid outside the cells)

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27
Q

The two components of ECF-

A

plasma

interstitial fluid

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28
Q

Intracellular fluid ICF

A

Fluid contained within all body cells

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29
Q

the seven factors homeostatically regulated are:

A
  • Concentration of nutrient molecules
  • Concentration of O2 and CO2
  • Concentration of waste products
  • pH
  • Concentration of water, salt, and other electrolytes
  • Volume and pressure
  • Temperature
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30
Q

The circulatory system contributes to homeostasis by?

A

Carries materials from one part of the body to another

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31
Q

The digestive system contributes to homeostasis by? (3 things)

A
  • Breaks down dietary food into smaller molecules that can be distributed to body cells
  • Transfers water and electrolytes from external environment to internal environment
  • Eliminates undigested food residues to external environment in the feces
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32
Q

The respiratory system contributes to homeostasis by? (2 things)

A
  • Gets O2 from and eliminates CO2 to the external environment
  • Important in maintenance of proper pH of internal environment
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33
Q

The urinary system contributes to homeostasis by?

A

• Removes excess water, salt, acid, and other electrolytes from plasma and eliminates them in urine.

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34
Q

Gout-

A
  • accumulation of uric acid in the blood. Causes severe joint pain
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35
Q

If you are severely dehydrated, drink ____ because ______

A

gatorade

it makes you drink more

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36
Q

How does the skeletal system work to maintain homeostasis? (4 things)

A
  • Provides support and protection for soft tissues and organs
  • Serves as storage reservoir for calcium
  • Along with muscular system enables movement of body and its parts
  • Bone marrow is ultimate source of all blood cells
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37
Q

How does the muscular system work to maintain homeostasis?

A

moves the bones

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38
Q

How does the integumentary system work to maintain homeostasis? (2 things)

A
  • Serves as outer protective barrier

* Important in regulating body temperature

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39
Q

How does the immune system work to maintain homeostasis? (2 things)

A
  • Defends against foreign invaders and against body cells that have become cancerous
  • Paves way for repairing or replacing damaged or worn-out cells
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40
Q

How does the nervous system work to maintain homeostasis? (2 things)

A
  • Controls and coordinates bodily activities that require rapid responses-reflexes.
  • Detects and initiates reactions to changes in external environment
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41
Q

How does the endocrine system work to maintain homeostasis? (2 things)

A
  • All hormone-secreting glands. Regulate numerous cellular activities
  • Especially important for controlling concentration of nutrients and, by adjusting kidney function, controls internal environment’s volume and electrolyte composition
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42
Q

How does the reproductive system work to maintain homeostasis? (tricky, 2 things)

A
  • Not essential for homeostasis (not essential for survival of individual)
  • Is essential for perpetuating the species
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43
Q

Leukemia-

A

cancer of the bone marrow. Abnormal accumulation of white blood cells. Lack of platelets. Blood clotting is affected

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44
Q

Glucagon and insulin. Which is more essential and why?

A

• Glucagon is more essential than insulin. It has 11 genes that do the same thing as it does. You cannot survive if your brain doesn’t have sugar.

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45
Q

In order to maintain homeostasis, homeostatic control systems must be able to: (3 things)

A
  • Detect deviations from normal in the internal environment that need to be held within narrow limits
  • Integrate this information with other relevant information
  • Make appropriate adjustments in order to restore factor to its desired value
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46
Q

disruptions to homeostasis can lead to

A

illness and death

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47
Q

Pathophysiology-

A

Abnormal functioning of the body associated with disease

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48
Q

Name three important roles of the plasma membrane:

A

o Controls movement of molecules between the cell and its environment
o Participates in joining cells to form tissues and organs
o Plays important role in the ability of a cell to respond to changes in the extracellular environment

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49
Q

The most abundant lipids of the plasma membrane are _______

A

phospholipids

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50
Q

Amphipathic-

A

having both a polar and nonpolar portion

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51
Q

carbohydrates are located on which side of cell membrane?

A

outer surface (extracellular) only

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52
Q

where is cholesterol located in the cell membrane and what does it contribute to?

A
  • Tucked between phospholipid molecules

* Contributes to fluidity and stability of cell membrane

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53
Q

Name five functions of membrane proteins:

A
  • Span membrane to form water-filled pathways, or channels across lipid bilayer
  • Serve as carrier molecules
  • Membrane-bound enzymes
  • Receptor sites
  • Cell adhesion molecules (CAMs)
  • Proteins on surface are important in cell-to-cell interaction/ recognition
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54
Q

which part of the phospholipid bilayer prevents solutes from crossing?

A

the hydrophobic interior

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55
Q

Membrane carbohydrates serve as _____

A

self-identity markers which enable cells to identify and interact with one another

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56
Q

Different carbohydrate concentrations on the membrane can be found in different _____

A

cell types

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57
Q

Name the 3 means by which cells are held together:

A
  1. extracellular matrix
  2. Cell adhesion molecules in cells’ plasma membranes
  3. Specialized cell junctions
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58
Q

extracellular matrix seves as biological “_____”

A

glue

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59
Q

three major types of protein fibers interwoven in extracellular matrix:

A

collagen, elastin, fibronectin

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60
Q

Collagen-

A

protein that forms flexible fibers or sheets

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61
Q

Scurvy-

A

vitamin C deficiency. Causes collagen fibers to be damaged. Results in bleeding in skin and mucous membranes.

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62
Q

Elastin-

A

Rubbery protein fiber. Abundant in lung tissue. Promotes flexibility.

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63
Q

Fibronectin-

A

Promotes cell adhesion. Holds cells in position. Reduced production in cancer cells that break free and metastasize

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64
Q

What two properties of particles influence whether they can cross cell membrane without assistance?

A
  • Relative solubility of particle in lipid

* Size of the particle

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65
Q

un-assisted membrane transport is called:

A

diffusion or osmosis

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66
Q

The four assisted membrane transports are:

A
  • Carrier-mediated transport
  • Facilitated transport
  • Active transport
  • Vesicular transport
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67
Q

Diffusion-

A

uniform spreading out of molecules due to their random intermingling

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68
Q

The tonicity of the extracellular solution determines what about a cell?

A

whether it will swell, shrink, or remain the same

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69
Q

Which assisted membrane transport requires that the carrier undergo a conformational change?

A

carrier-mediated transport

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70
Q

Carrier-mediated transport can be active or passive, depending on ______

A

concentration gradients

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71
Q

Characteristics that determine the kind and amount of material that can be transferred across the membrane via carrier-mediated transport:

A
  • Specificity
  • Saturation
  • Competition
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72
Q

Facilitated diffusion is an assisted membrane transport that falls under the sub-category of ______ transport.

A

carrier-mediated

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73
Q

Active transport is also in the sub-category of _____ transport just like facilitated diffusion, with the key differences being that active transport moves molecules ________ their concentration gradient

A

carrier-mediated

against

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74
Q

primary active transport requires _____, while secondary active transport is driven by _____

A
  • ATP

- An ion concentration gradient established by a primary active transport system

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75
Q

Vesicular transport-

A

Material is moved into or out of the cell wrapped in membrane

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76
Q

Pinocytosis-

A

“cell drinking” nonselective uptake of extracellular fluid droplets

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77
Q

Phagocytosis-

A

-“cell-eating” selective uptake of solid particles

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78
Q

Exocytosis-

A

Provides mechanism for secreting large molecules

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79
Q

Most depression medications, such a Prozac, are SSRI’s, which stands for

A

Selective Serotonin Re-Uptake Inhibitors

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80
Q

• Serotonin is a neurotransmitter in the _______ nervous system. Produces a feeling of __________

A

central

pleasure, euphoria, and general well-being.

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81
Q

Many people who suffer from depression are deficient in ________

A

Serotonin

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82
Q

How do SSRI’s treat depression?

A

SSRI’s block Endocytosis, so instead of serotonin binding the receptor and being taken into neuron B, it is allowed to keep binding the serotonin receptor, producing a constant feeling of well-being.

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83
Q

Membrane potentials are in reference to the inside/outside of a cell?

A

inside

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84
Q

Resting membrane potential-

A

Constant membrane potential present in cells of non-excitable tissues and those of excitable tissues when they are at rest

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85
Q

The _________ is the most important active transport system, and helps contribute to the ____________

A

Na+/ K+ ATPase

resting membrane potential of some cells

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86
Q

How the Na+/ K+ ATPase works:
It binds ______ from the cytosol, then undergoes a conformational change after being phosporylated by ATP. Following the conformational change, __________ Dephosphorylation returns the transporter to original conformation, and ________

A
  • 3 Na+
  • 3 Na+ are released to extracellular and 2 K+ are picked up
  • K+ is released to cytosol
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87
Q

Effect of sodium-potassium pump on membrane potential makes a small/large contribution to membrane potential?

A

small

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88
Q

The biggest influence on resting membrane potential is _________

A

the relative permeability, or “leakiness” of ion channels.

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89
Q

Why does K+ desire an equilibrium potential of -90?

A
  1. The concentration gradient for K+ tends to move this ion out of the cell.
  2. The outside of the cell becomes more positive as K+ ions move to the outside down their concentration gradient.
  3. The membrane is impermeable to the large intracellular protein anion (A-). The inside of the cell becomes more negative as K+ ions move out, leaving behind A-..
  4. The resulting electrical gradient tends to move K+ into the cell
  5. No further net movement of K+ occurs when the inward electrical gradient exactly counterbalances the outward concentration gradient. The membrane potential at this equilibrium point is the equilibrium potential for K+ (EK+ ) at -90 mV.
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90
Q

Why does Na+ desire an equilibrium potential of +60?

A
  1. The concentration gradient for Na+ tends to move this ion into the cell
  2. The inside of the cell becomes more positive as Na+ ions move to the inside down their concentration gradient
  3. The outside becomes more negative as Na+ ions move in, leaving behind in the ECF unbalanced negatively charged ions, mostly Cl-.
  4. The resulting electrical gradient tends to move Na+ out of the cell
  5. No further net movement of Na+ occurs when the outward electrical gradient exactly counterbalances the inward concentration gradient. The membrane potential at this equilibrium point is the equilibrium potential for Na+ (ENa+) at +60 mV.
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91
Q

Equilibrium potential-

A

The membrane potential for a particular ion in which the chemical gradient and the electrical gradient completely balance each other out.

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92
Q

Its important to keep in mind that the membrane potential will ALWAYS be closest in value to the ________________

A

equilibrium potential of the most permeable ion at that time

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93
Q

the resting membrane potential is -70 mV, because the membrane is ___ times more permeable to K+ than to Na+

A

30

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94
Q

o Since relative ion concentrations are constantly varying, one would expect the equilibrium potential for individual ions to vary as well. So, how is the equilibrium potential (Eion) calculated?

A

The Nernst Equation

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95
Q

The nernst equation allows you to calculate ______ if ________ is known.

A

equilibrium potential

the relative ion concentrations are known.

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96
Q

The Nernst Equation is defined as:

A

E(ion) = 61/z log [(ion conc. outside cell)/(ion conc. inside cell)]

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97
Q

What two major regulatory systems ensure survival of the body?

A

The nervous and endocrine systems

98
Q

What two tissues are excitable?

A

nerve and muscle

99
Q

Nerve and muscle tissue can turn their resting potentials into _______

A

electrical signals

100
Q

• Any state when the membrane potential is other than 0 mV, means that there is a separation of charge

A

Polarization

101
Q

• Membrane becomes less polarized than at resting potential. A result of the inside of the cell becoming more positive

A

Depolarization

102
Q

• Membrane returns to resting potential after having been depolarized.

A

Repolarization

103
Q

• Membrane becomes more polarized than at resting potential. A result of the inside of the cell becoming more negative.

A

Hyperpolarization

104
Q

________ serve as short distance signals

A

Graded potentials

105
Q

In graded potentials, the response is directly related to ________

A

size of the stimulus.

106
Q
Action potentials:
Distance =
speed =
size =
energy use =
A

long distance
very fast
all the same size
energy costly

107
Q

Voltage-

A

A measure of electrical potential energy. Measured in volts. Millivolts are used in the body, not a big voltage

108
Q

Ohm’s law:

A

V=IR

109
Q

Formation of a Graded Potential begins with an event that triggers ________

A

opening of local membrane ion channels, usually Na+

110
Q

The site of initiation of a graded potential is called the _______, and it refers to the _____________________

A
  • active site

- inside and the outside of the membrane in that area.

111
Q

In a graded potential, Depolarization spreads out in what direction?

A

-all directions

112
Q

how much sodium flows into a cell during a graded potential?

A

very little, much less than an action potential

113
Q

A triggering event size is directly related to the size of a graded potential because a larger stimulus causes ________

A

more channels to be opened, resulting in a larger influx of Na+ ions.

114
Q

Graded potentials die over short distances because?

A

charge-carrying ions (K+) leak out through leaky channels in un-insulated parts of the membrane (de-myelinated regions)

115
Q

Auto-immune disease that results in the de-myelination of axons in the CNS and PNS

A

Multiple sclerosis

116
Q

Multiple sclerosis occurs because graded potentials diminish too quickly due to ________, resulting in ___________

A
  • leakage of K+ through ion channels

- difficulty in locomotion, vision, and constant pain (neuropathy)

117
Q

Action potentials are defined as brief, rapid, large (up to _____ mV) positive changes in membrane potential during which potential actually _______.

A
  • 100

- reverses (inside of membrane becomes temporarily more positive)

118
Q

Action potentials involve what portion of the total excitable cell membrane at a time?

A

a very small portion

119
Q

Do action potentials decrease in strength as the propagate?

A

NO

120
Q

At what point will an action potential form?

A

the threshold potential

121
Q

What kind of channels allow for an action potential to occur?

A

voltage gated ion channels

122
Q

Refractory period does what?

A

keep the spread of depolarization from going too far beyond the active site and allows for one way propagation.

123
Q

In an action potential, the flow of sodium ions in the intracellular fluid reverses the membrane potential from ____ to _____

A

-70mV to +30 mV

124
Q

After an action potential, what restores the membrane potential to the resting state?

A

Flow of potassium ions into the extracellular fluid

125
Q

At what potential are Na+ and K+ equally permeable?

A

-15 mV, because it is half the distance between -90 and +60

126
Q

Voltage gated Na+ channels have what two gates?

A

an activation gate and an inactivation gate.

127
Q

Which Na+ voltage gate is most important?

A

inactivation gate, it is like the lock on a door

128
Q

what is the shape of the inactivation gate?

A

ball and chain

129
Q

Activation gate is found where? and works like a ________ allowing Na+ to cross.

A

interior of the channel

sliding door

130
Q

Inactivation gate is found on the side of the channel facing the ________, and is similar in structure to a ball and chain. The ball clogs the channel pore when the channel is closed, and hangs freely when the channel is open.

A

cell interior

131
Q

Which gates must be open for Na+ to cross?

A

BOTH

132
Q

What three conformation can the Na+ voltage gate be found in?

A
  1. Closed, but capable of opening (Activation gate is closed (inner part), but inactivation gate is open (ball and chain))
  2. Open (Both gates are open, Na+ is allowed to cross)
  3. Closed, and not capable of opening (activation gate open, inactivation gate is closed). This occurs when channels are inactivated. Called refractory period. Another action potential cannot be initiated until these channels de-inactivate following hyperpolarization of the membrane.
133
Q

What is the difference between absolute and relative refractory period?

A

In absolute, all inactivation gates are closed. In relative, fewer gates are closed. Gates are closed in both cases, just fewer gates in relative refract.

134
Q

What is the reason for refractory period?

A

All nerves need to fire the same. If the nerve impulses build upon each other, you would get something analogous to tetanus in muscles. This could stop your heart. So refractory period is necessary to reset the action potential so action potentials don’t build upon each other.

135
Q

What kind of gates does the voltage gated K+ channel have?

A

only one activation gate

136
Q

Sodium channels open during ________ by positive feedback

A

Depolarization

137
Q

When the sodium channels become inactive, ____________. This repolarizes the membrane

A

the channels for potassium open.

138
Q

Which channels are responsible for hyperpolarization and why?

A

K+

because they are slow to open and close.

139
Q

Which is more energy costly, and action potential or graded potential?

A

Action potential

140
Q

Positive feedback-

A

the input and the output are identical.

Mosquito bite→ scratch→ histamine release→ causes more itching→ releases more histamine

141
Q

Negative feedback-

A

most feedback mechanisms. The input and output are opposites.
Increase in blood sugar→ release of insulin→ decrease in blood sugar

142
Q

At rest, which channels are open and which are closed?

A

all the voltage-gated channels are closed, but numerous K+ leak channels, and very few Na+ leak channels are open

143
Q

At threshold potential, the membrane is about ____ times more permeable to Na+ and K+

A

600

144
Q

The voltage-gated Na+ channels are activated at slightly different changes in voltage. So, it takes more depolarization to open some, while only a small amount to open others. o So during the initial depolarization, more channels are opened as ____________

A

the membrane becomes depolarized.

145
Q

o This is defined as the membrane potential at which enough voltage-gated Na+ channels have been opened to initiate the positive feedback cycle that will open the remaining channels.

A

Threshold potential

146
Q

Upon reaching the threshold potential, why does the membrane potential not reach +30?

A

Because Na+ channels begin to be inactivated, decreasing permeability

147
Q

During the stretch from ________________ on an action potential, all of the voltage gated Na+ channels are inactivated. At that point, no stimulus, regardless of how large, can activate the Na+ channel.

A

the peak to the end of the red line (-70 mV)

148
Q

Most commonly missed question: During relative refractory period, which channels are closed/open/inactivated. The wrong answer is that they are all closed but not inactivated.

A

A: some but not all channels are inactivated

149
Q

Can a stimulus produce a response during relative refractory period? Absolute?

A

Yes during relative if the stimulus is large

Never during absolute

150
Q

Which comes first, relative or absolute refractory period?

A

Absolute

151
Q

There is always more Na+ outside/inside the cell and more K+ outside/inside the cell.

A

outside

inside

152
Q

What restores concentration gradients disrupted by action potentials?

A

o The Na+/K+ pump

153
Q

List the basic parts of a neuron

A
  • Cell body
  • Dendrites
  • Axon
  • Axon Hillock
  • Axon terminals
154
Q

Action potentials are initiated at the _________ and conducted throughout a nerve fiber

A

Axon Hillock

155
Q

Neuron cell body functions:

A
  • Houses the nucleus and organelles

* Receives and integrates signals from other nerve cells

156
Q

Dendrites function:

A
  • Project from cell body and increase surface area available for receiving signals from other nerve cells
  • Signal toward the cell body
157
Q

Neuron cell body is also called the ______

A

soma

158
Q

____ and ____ serve as a neuron’s input zone

A

dendrite and cell body

159
Q

An axon is also called a ______

A

nerve fiber

160
Q

Axon function:

A
  • Single, elongated tubular extension that conducts action potentials away from the cell body
  • Conducting zone of the neuron
161
Q

collaterals-

A

side branches of an axon

162
Q

Axon hillock-

A
  • First portion of the axon plus the region of the cell body from which the axon leaves
  • Neuron’s trigger zone
163
Q

means “touching” or “next to”

A

contiguous

164
Q

Contiguous conduction occurs in what kind of nerve fibers?

A

un-myelinated

165
Q

Action potentials spread along every portion of the membrane in _______ conduction

A

contiguous

166
Q

Means to “jump”

A

saltatory

167
Q

Saltatory conduction occurs in:

A

myelinated nerve fibers

168
Q

In saltatory conduction, impulse jumps over ______________.

A

sections of the fiber covered with insulating myelin (biological insulation)

169
Q

Is the magnitude of an action potential dependent on the strength of a stimulus?

A

No

170
Q

Period following a stimulus in which the voltage-gated Na+ channels cannot open until the resting potential is restored. Period is over when these channels are in the closed-but-capable-of-opening conformation.

A

Absolute refractory

171
Q

. A second action potential can be initiated, if the stimulus is stronger than what is normally required.

A

relative refractory

172
Q

Exist between regions of myelinated nerve fiber.

A

Nodes of Ranvier

173
Q

Myelinated fibers conduct impulses about ____ times faster than unmyelinated fibers of comparable size

A

50

174
Q

Myelin is primarily composed of _____, formed by ________ in CNS, and formed by _________ in PNS

A

lipids
oligodendrocytes
Schwann cells

175
Q

o Besides myelin, our bodies have evolved __________ to transmit electrical impulses more quickly.

A

larger diameter axons

176
Q

Faster conduction from larger axon diameter is due to _____ and _____.

A

-less internal resistance to local current flow and higher surface area

177
Q

Higher surface area on axons leads to faster propagation because __________, however the downside is that _________

A
  • more voltage-gated channels are available to carry current.
  • The downside to this is that there are more leak channels as well.
178
Q

Large myelinated fibers that innervate skeletal muscle ~___ mph.
Small, unmyelinated fibers that innervate the digestive tract ~___ mph.

A
  • 270

- 2

179
Q

Fibers in _____ can regenerate with the help of ________. Fibers in ______ do not have regeneration ability. (The axons themselves do regenerate, but die off quickly)

A

PNS

CNS

180
Q

_________ inhibit regeneration of cut central axons

A

Oligodendrocytes

181
Q

From an evolutionary stand point, its better to have _____ neurons than _____ neurons.

A

less

improperly functioning

182
Q

Regeneration in the CNS is believed to be inhibited by a protein called ______

A

Nogo

183
Q

Recent research into CNS damage has involved:

A
  • Function-blocking antibodies to Nogo in mice.
  • Peripheral nerve grafts
  • Neural stem cells
  • Using enzymes to break down scar tissue at sites of injury
184
Q

The two types of synapses:

A

Electrical and Chemical synapses

185
Q

Electrical Synapses-

A

Two neurons connected by gap junctions. Fly’s response when you go to swat them. Quick. Example is like the hotel door separating two rooms, that’s an analogy for a gap junction.

186
Q

Chemical Synapses-

A

Chemical messenger is transmitted across the junction separating the two neurons. Slower, but more reliable.

187
Q

Vesicles full of neurotransmitter do not leave the presynaptic membrane, they _______

A

FUSE WITH MEMBRANE and release neurotransmitter

188
Q

EPSP:
IPSP:

A

Excitatory post-synaptic potential

Inhibitory post-synaptic potential

189
Q

Excitatory synapses –

Inhibitory synapses –

A
  • bring the membrane potential higher

- anions entering the cell (more negative); essentially turning it off

190
Q

What will happen if a neuron recieves both an excitatory and inhibitory input at the same time?

A

they will cancel each other out

191
Q

Temporal summation-

A

One excitatory nerve impulse too weak to cause an action potential is followed by another one quickly after before the first comes back down to rest that will boost the postsynaptic membrane to threshold

192
Q

Spatial summation-

A

A post-synaptic membrane is brought to threshold due to simultaneous activation of two (Ex1 & Ex2) or more excitatory presynaptic inputs that individually would not have brought the membrane to threshold.

193
Q

Name 8 common neurotransmitters

A
  • Acetylcholine
  • Dopamine
  • Norepinephrine
  • Epinephrine; another name for adrenaline.
  • Serotonin
  • Glycine
  • Glutamate
  • Gamma-aminobutyric acid (GABA)
194
Q

neurotransmitters vary from _________, but the same neurotransmitter is always released at _________

A
  • synapse to synapse

- one particular synapse

195
Q

How large are neuropeptides?

A

2 to 40 amino acids

196
Q

Neuropeptides are synthesized in ______________

A

neuronal cell body in the endoplasmic reticulum and Golgi complex

197
Q

Neuropeptides’ effects on cells are _____ term

A

long

198
Q

Neuropeptides are considered ________ because they don’t cause the formation of EPSP or IPSP, but bring about ______ that subtly modulate, depress or enhance the action of the synapse. They are important in learning, motivation and satiety.

A
  • neuromodulators

- long-term changes

199
Q

Name 4 neuropeptides

A

CCK (cholecystokinin), dopamine, glutamate, histamine.

200
Q

Any given drug that interacts with the nervous system will affect synapses in one of which 3 ways?

A
  1. Altering the synthesis, axonal transport, storage, or release of a neurotransmitter
  2. Modifying neurotransmitter interaction with the postsynaptic receptor
  3. Influencing neurotransmitter reuptake or destruction (like depression medication)
201
Q

How does cocaine alter synaptic transmission?

A
  • Blocks reuptake of neurotransmitter dopamine at presynaptic terminals
  • Causes a feeling of euphoria
  • Your tolerance for dopamine will go through the roof if you are addicted to cocaine– instead of feeling normal when you stop, you feel terrible, which is when you have withdrawal
202
Q

How does tetanus toxin alter synaptic transmission?

A

• Prevents release of inhibitory neurotransmitter GABA, affecting skeletal muscles. Spastic paralysis – can’t unclench a muscle. (Lockjaw)

203
Q

How does strychnine alter synaptic transmission?

A

• Competes with inhibitory neurotransmitter glycine at postsynaptic receptor site. Spastic paralysis, convulsions, muscle spasticity, and death.

204
Q

List the 4 types of chemical messengers.

A

paracrines, neurotransmitters, hormonal singals, neurohormones

205
Q

Paracrines:
Do they enter bloodstream?
Which cells do the affect?
Provide example:

A
  • No
  • only neighboring cells in immediate environment of secretion site.
  • histamine
206
Q

Neurotransmitters:

  • Range =
  • Respond to?
  • How does it reach it’s target?
  • Give an example?
A
  • short range chemical messengers
  • respond to electrical signals (action potentials)
  • diffuses across narrow space to act locally on adjoining target cell (another neuron, a muscle, or a gland)
  • Acetylcholine
207
Q

Hormonal signaling:

  • Range?
  • Released by?
  • example?
A
  • long range
  • endocrine glands
  • Insulin
208
Q
Neurohormones:
Do they enter the blood?
What are they released by?
Range?
Example?
A
  • Yes
  • neurosecretory neurons
  • long range
  • Vasopressin
209
Q

Extracellular chemical messengers bring about cell responses primarily by _______

A

signal transduction

210
Q

Signal transduction-

A

o The process by which a target cell receives incoming chemical signals and transforms them into a particular cellular response

211
Q

Binding of extracellular messenger (first messenger) to matching receptor brings about desired intracellular response by either _________ or ______________.

A

-Opening or closing channels or activating second-messenger systems

212
Q

Second messengers help produce the cellular response to a first messenger by __________

A

Relaying message to intracellular proteins that carry out dictated response

213
Q

Endocrinology-

A

Study of homeostatic activities accomplished by hormones.

214
Q

What are the two distinct groups of hormones?

A

Hydrophilic hormones and lipophilic hormones

215
Q

Extracellular signals can cause a tit-load of different responses. Some will open or close channels. _______ a channel is more common in this case.

A

opening

216
Q

The two signal transduction pathways that are triggered by most extracellular hydrophilic hormones are:

A

Tyrosine kinase pathway and GPCR pathway

217
Q

Kinase-

A

an enzyme that transfers a phosphate group from ATP to an intracellular protein, through a process called phosphorylation.

218
Q

Kinases generally trigger a ________, resulting in ________

A
  • signaling cascade

- activation of the final set of proteins that produce the desired effect in the cell.

219
Q

In the tyrosine kinase pathway, the receptor is also responsible for ________, making it a receptor as well as an enzyme.

A

kinase activity

220
Q

Tyrosine Kinase pathway:
• Ligand binding to receptors triggers a process called ________, where one receptor __________. Then the receptors ______________, or add phosphate groups to themselves.

A
  • dimerization
  • combines with another
  • autophosphorylate
221
Q

RTK pathway:
o Once dimerization and autophosphorylation have occurred, the receptor recruits cellular proteins to the membrane, where they ___________ and begin the _______________

A
  • are also phosphorylated

- signaling cascade that leads to a cellular response.

222
Q

Kinases come in 3 classes:______________, depending on the amino acid sites on the substrate proteins that they phosphorylate

A

-serine, threonine, and tyrosine kinases

223
Q

A G-protein coupled receptor is a protein that crosses the membrane __ times and is coupled to a ____________. Upon binding of the signaling molecue to the G-protein, the ______ dissociates and binds an effector molecule, which is usually an enzyme. Binding of the α subunit triggers activation of the effector protein, which generally results in the production of _________.

A
  • 7
  • heterotrimeric G-protein ( α, β, and γ subunits).
  • α subunit
  • a second messenger
224
Q

In GPCR pathway, the second messenger initiates a signaling cascade, which often includes activation of _________, that leads to a cellular response

A

protein kinase

225
Q

About half of all drugs prescribed today act on ________________

A

G-proteins or some part of the G-protein pathway

226
Q

Examples of GPCR’s are (4):

A
  • Light-activated rhodopsin for night vision.
  • Thousands of odorant receptors.
  • Receptors for hormones.
  • Receptors for neurotransmitters.
227
Q

Epinephrine acts on GPCR’s. Based on which cell the receptor is attached to, epinephrine can elicit various responses. List 4 epinephrine receptors and their cellular response.

A
  1. β-adrenergic receptors on hepatocytes and adipose cells. To release glucose and fatty acids for quick energy (ATP) production
  2. β-adrenergic receptors on muscle heart cells to increase contraction rates and force. To better transport oxygen and nutrients to muscle cells
  3. β-adrenergic receptors on smooth muscle cells of the intestines; causes them to relax. To temporarily shut down digestive functions.
  4. α2 adrenergic receptors in smooth muscles lining blood vessels of skin, intestine, and kidney to constrict vessels to cut off blood flow. To shunt blood to skeletal muscles, heart, and brain. “looks like you’ve seen a ghost”
228
Q

Epinephrine binds ß-adrenergic receptors to activate _________, which activates _________. On the other hand, _____ or _____ bind α1 and α2 adrenergic receptors to activate ____ which then inhibits adenylyl cyclase.

A
  • Gs
  • adenylyl cyclase
  • PGE1 (Prostaglandin E1) or Adenosine
  • Gi
229
Q

adenylyl cyclase catalyzes:

A

ATP → cAMP (second messenger)

230
Q

Adenylyl cyclase is under _________ control

A

both positive and negative

231
Q

Adenylyl cyclase generally has __ catalytic domains and _____ transmembrane domains with _____ helices each

A
  • 2
  • 2
  • 6
232
Q

cAPKs-

Example:

A
  • cAMP dependent protein kinases

- PKAs and Ser/Thr kinases

233
Q

cAPks have 2 ______ subunits and 2______ subunits

A

regulatory, catalytic

234
Q

cAPK tetramer is active/inactive? Binding of 2 molecules of cAMP on each _____ subunit causes activation/inactivation?

A
  • inactive
  • regulatory
  • activation
235
Q

cAPKs (like PKA) exhibit __________, in that the binding of cAMP to the first subunit drops the Kd for the second binding

A

cooperativity

236
Q

Neurotransmitters themselves don’t differ from one cell to the next. What differs is the
___________

A

receptor type.

237
Q

Acetylcholine causes skeletal muscles to contract by binding ___________ at the neuromuscular junction, which opens and allows __________ to enter and depolarize the muscle cell, leading to contraction.

A
  • nicotinic acetylcholine receptors

- Na+

238
Q

Smoking while pregnant is especially bad, because fetus receives more nicotine than you do, which can _______________

A

disrupt the development of acetylcholine nerves/receptors

239
Q

Acetylcholine causes heart muscle cells to _____________ by binding ______________, causing a release of ____ from the cell which causes sustained ________

A
  • slow contraction rates
  • muscarinic acetylcholine receptors on heart muscle cells
  • K+
  • hyperpolarization of the cell membrane
240
Q

Acetylcholine binding in heart cells activates _______ to open K+ channels.

A

Gßγ subunit