Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology > Action potential > Flashcards

Action potential Flashcards

1
Q

the only movement of ions through the membrane is ___________ , as demonstrated by the open channels between the potassium symbols (K+ ) inside and outside the membrane.

A

diffusion of potassium ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The Resting Membrane Potential Is Established by the :

A

Diffusion Potentials,
Membrane Permeability, and
Electrogenic Nature of the Sodium-Potassium Pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

high ratio of potassium ions inside
to outside

A

35 : 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Nernst potential corresponding to
this ratio is ___________ because the logarithm of 35 is 1.54, and this multiplied by −61 millivolts is __________

A

94 millivolts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The ratio of sodium ions from
inside to outside the membrane is 0.1, which gives a calculated Nernst potential for the inside of the membrane of _________

A

+61 millivolts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Is Used to Calculate the Diffusion Potential When the Membrane Is Permeable to Several Different Ions

A

The Goldman Equation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

sodium potassium pump transport :

A

3 sodium to the outside
2 potassium into the cell

continual loss of positive ions inside the membrane

further negativity of about -4 millivolts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In the normal nerve fiber, the
permeability of the membrane to potassium is about ______ as great as its permeability to sodium. Using this value in the Goldman equation gives a potential inside the membrane of −86 millivolts, which is near the potassium potential

A

100 times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

when u talk about membrane potential, consider the:

A
  • concentration and charge of ions
  • permeability of cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

which are rapid changes in the membrane potential that spread
rapidly along the nerve fiber membrane.

Each action
potential begins with a sudden change from the normal resting negative membrane potential to a positive potential and ends with an almost equally rapid change back to the negative potential.

A

action potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

NEURONAL ACTION POTENTIAL stages:

A
  1. RESTING STAGE
    - before action potential occurs
  2. DEPOLARIZATION STAGE
    - membrane becomes permeable to sodium ions
  3. REPOLARIZATION STAGE
    - voltage gated ions start to close
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The membrane is said to be “polarized” during this stage

A

Resting Stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

membrane suddenly becomes permeable to sodium ions, allowing tremendous numbers of positively charged sodium ions to
diffuse to the interior of the axon.

The normal “polarized”
state of −90 millivolts is immediately neutralized by the inflowing positively charged sodium ions, with the potential rising rapidly in the positive direction—a process called depolarization.

A

DEPOLARIZATION STAGE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Within a few 10,000ths of a second after the membrane becomes highly permeable to
sodium ions, the sodium channels begin to close and the potassium channels open to a greater degree than normal.

A

Repolarization Stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

are transmitted via an action potential. It is a very rapid changes in the membrane potential. And begins with a resting potential which turns to becoming positive potential, then end
with resting potential again.

A

Neuronal signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

are necessary for both DEPOLARIZATION and
REPOLARIZATION of the neuronal membrane during the action potential.

A

Voltage-gated sodium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

also play an important
role in the increasing the rapidity of repolarization of the membrane for potassium.

A

voltage-gated sodium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

both voltage-gated channels are addition to the
_______ & __________ which establish the resting membrane potential of the membrane.

A

sodium-potassium pump
sodium-potassium leak channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

SUMMARY OF THE EVENTS THAT CASUSES THE
ACTION POTENTIAL

A
  1. Resting State
  2. Onset of Action Potential
  3. End of Action Potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q
  • before action potential, there is a conductance of
    potassium ions which are about 100 times as
    greater as the conductance of sodium ions.
  • Cause by the greater leakage of potassium ions
    than sodium ions through leak channels.
A

Resting State

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q
  • voltage-gated sodium channels become activated
    instantly allowing about 5000 volts increase in the
    permeability which was identified as sodium
    conductance.
  • result to voltage gating of potassium channels
    causing them to slowly open
A

Onset of Action Potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

End of Action Potential

A
  • Return to a resting membrane potential state
  • potassium channels are closed back to its original
    state
  • It only happens after a delay
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

-The voltage-gated sodium channels opens when there is a rise in the membrane potential (specifically, -90 mv to 0)
-The rise and the opening of the voltage-gated sodium channels cause a further rise of membrane potential.
-The rise of the membrane potential, allows a rapid in-flow of ions. An example of

A

POSITIVE FEEDBACK CYCLE.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

ACTION POTENTIAL DOES NOT OCCUR UNTIL
THRESHOLD POTENTIAL HAS BEEN REACHED

A

A sudden rise from -90mv to -65mv causes an explosive development of the action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

is when sodium ions are greater than the number of the potassium ions leaving the neurons

A

threshold potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

NEW ACTION POTENTIAL CANNOT OCCUR WHEN
MEMBRANE IS STILL DEPOLARIZED FROM PRECEDING ACTION POTENTIAL

why?

A

After action potential is initiated, sodium ion channel are INACTIVATED

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

any amount of stimulation cannot open the inactivated gates. It can only be opened when the membrane potential is back to its:

A

original resting membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

2 Things Presends:

A
  1. Absolute Refractory Period
  2. Relative Refractory Period
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q
  • action potential cannot be elicited
  • Around 2500 impulses per second are transmitted
A

Absolute Refractory Period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q
  • allows refractory period is stronger than normal
    stimulus to excite nerve fiber. (for action potential
    to be initiated)
A

Relative Refractory Period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Action potential elicited at any point in a
membrane would usually excite adjacent portions,
which results to

A

PROPAGATION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Transmission along neuron or muscles is called
_______

(Undergoes an all-or-nothing principle)

A

neuronal or muscular impulse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Re-establishing Sodium and Potassium Ionic Gradients After Action Potentials are Completed – Importance of Energy Metabolism

A

Transmission of each impulse along the nerve fiber reduces infinitesimally the concentration differences of sodium and potassium

It is necessary to re-establish the sodium and potassium concentration differences across the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

As sodium enters the cell so does water. When the pump does not work normally, the cell will then swell.

A

problem in sodium channel pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Large Nerve Fibers Are Myelinated and Small
Ones Are

A

Unmyelinated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Surrounding the larger axons is a thick myelin sheath
deposited by _______

A

Schwann cells (sphingomyelin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

At the juncture between two successive Schwann cells, a small noninsulated area only 2 to 3 micrometers in length remains where ions can still flow with ease between the extracellular fluid and the axon interior

A

nodes of Ranvier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

the membrane of the axons is used for conduction of

A

action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

“Saltatory” Conduction Occurs in

A

Myelinated Fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

is when ions flows with ease through nodes of Ranvier. Thus, the neuronal impulse “jumps” from node to node along the fiber

A

Saltatory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Saltatory conduction is of value for two reasons:

A

Increased velocity.
Energy conservation.

42
Q
  • by causing depolarization process jump along
    intervals, there is an increase of velocity neuronal
    transmission from 5 to 50 folds.
A

Increased velocity.

43
Q

around _________ of the body mass is around skeletal muscle and around 10% is smooth muscles and cardiac muscles where it’s principles of contraction revolve around nerve fibers

A

40%

44
Q
  • changes in ions require energy in the form of ATP
  • Saltatory conduction conserves energy for axon.
A

Energy Conservation

45
Q

Conduction Velocity Is Greatest in

A

Large, Myelinated Nerve Fibers.

-the velocity increases with the fiber diameter in myelinated fibers

(in unmyelinated, square root increase only)

46
Q

Velocity of action potential conduction nerve fiber varies from 0.25 m/s to 100 m/s in __________ & ______ fibers respectively.

A

unmyelinated and myelinated

47
Q

electrical to chemical using _____ in contraction of muscle

A

calcium ions

48
Q

needed as it conserves energy, since
both muscle contraction and muscle relaxation is very dependent with ATP.

A

saltatory conduction

49
Q

living tissue.
has its own stroma (made of calcium and phosphate)

hard tissue to support body
contradict with the pull of gravity
(from mechanical to chemical signal)

A

Bones

50
Q

In the muscle the specific area where there is a communication of the nerve is in the _____________,

where the mode of communication become electrical to chemical and the involvement of calcium to initiate muscle contraction.

A

myofibril

51
Q

Muscle contraction and relaxation is very dependent on

A

ATP

52
Q

-We grow because we first had our __________.
- we are able to move our joints because of our ______________

A

cartilage

53
Q

________________is avascular.

So, if you damaged the it, it will be hard to generate because of the lack of its lack of blood
vessels.

A

cartilage

54
Q

__________common in older people, because the cartilage suffers from the wear and tear of the body.

The cartilage will thin out or will be gone causing to have a friction on the joints.

A

Osteoarthritis

55
Q

In growing years cartilage is very active, but at around __________ years old it will slowly lose its activity and capacity.

A

20-25

56
Q

3 types of cartilage:

A
  1. Hyaline Cartilage
  2. Elastic Cartilage
  3. Fibrocartilage
57
Q

where the cartilage is residing

A

Lacuna

58
Q

in some areas of the body is
composed of glycosaminoglycans. Which will
potentially/eventually solidify and become bone.

A

extracellular matrix

59
Q

Composed mostly of type II collagen
and glycosaminoglycans; appear homogenous, glassy

Attract water that provides resilience
and allows diffusion of metabolites
throughout avascular cartilage tissue

A

Hyaline cartilage

60
Q

the cartilage cells

able to survive because of the
extracellular matrix which contains the nutrients.

A

Chondrocytes

61
Q

fibers in pinna of the external ear

A

Elastic Cartilage

62
Q

Firm, solid tissue that resembles dense connective tissue

Pubic symphysis, annulus fibrosus of intervertebral
discs, menisci

A

Fibrocartilage

63
Q

Cartilage is avascular- thus it relies heavily on the ____________ of nutrients from the vessels of the
perichondrium or to the surrounding tissues

Also attributes to the slow and limited ability to heal
and repair when injury occurs.

A

active diffusion

64
Q

mainly occurs during
embryonic and fetal development and childhood and
this slowly decreases in adolescence and in adults
almost little to no growth

A

Growth of the cartilage

65
Q

TWO TYPES OF GROWTH IN THE CARTILAGE

A
  1. Appositional growth
  2. Interstitial growth
66
Q

where in the chondroblasts (cartilage producing cell) located in the perichondrium produce cartilaginous matrix and thicken the cartilage from the periphery.

Once the chondroblast became
incasing matrix they become chondrocyte.

A

Appositional growth

67
Q

chondrocyte in the middle of the
cartilage divide and each daughter cell starts to secrete cartilaginous matrix around itself eventually becoming separated from each other by a newly produce cartilaginous matrix

A

Interstitial growth

68
Q

a group of chondrocyte that arose
from a single chondrocyte during interstitial growth

A

Isogenous cells

69
Q

Osteoprogenitors: Pool of mesenchymal stem cells,
stellate to squamous morphology

Give rise to osteoblasts

A

Osteoprogenitors

70
Q

Active: Cuboidal to columnar with basophilic cytoplasm and euchromatic nuclei and distinct
nucleoli
b. Inactive: Squamous

Secrete osteoid

Innermost layer of periosteum; endosteum

A

Osteoblasts

71
Q

convert mechanical to chemical stimulus.

A

Mechanotransduction

72
Q

Osteoblasts encased in calcified matrix
mature and become osteocytes

Maintain bony matrix; mechanotransduction

Main cell body in lacunae, cell processes in canaliculi

A

Osteocytes

73
Q

Large, multinucleated macrophage derivative

Howship lacunae

A

Osteoclasts

74
Q

Dense connective tissue

Deliver neurovascular supply to the bone,
allow tight attachment of the muscles and
other structures to the bone

Outer surfaces of most compact bones

A

Periosteum

75
Q

Resembles simple squamous epithelium
composed of inactive osteoblasts, osteoprogenitors, and osteoclast

Source of new osteoblasts and osteocytes

Inner surfaces of compact bones, canals;
outer surfaces of all sponge bones

A

Endosteum

76
Q

it is where blood is produce

A

Marrow space

77
Q

Mechanical support, protection,
weight transfer, mineral
storage

Outer surfaces of the
bones

A

Compact bone

78
Q

Weight transfer, quick mineral turnover

Inner portion of the bones

A

Sponge bone

79
Q

Site of blood formation and fat storage, lighten
the weight of the bone

Spaces in between
the sponge bone TRABECULAE

A

Marrow space

80
Q

Dense outer portions of the bone

Weight bearing, weight transfer, protection, site for
muscle attachment

Peripheries of most bone; thicker in the
diaphysis of long bones

A

compact bone

81
Q

has
- concentric lamellae
-initially, it has collagenous fibers running each length
-eventually it will be calcified
-fiber oriented in a very minimal manner so that it can have the
-greatest capacity for weight transfer
-has Cement lines which are Darker staining line
-has Osteocytes in the lacunae
-the dot-like opening between the layers of the lamellae

A

COMPACT BONES

82
Q

✓ is composed primarily of plates or branches of bony
tissues
✓ play some role in weight transfer
✓ reduce the weight of the bone
✓ this architecture provides large area for bone
resorption and formation

A

SPONGE (CANCELLOUS/MEDULLARY) BONE

83
Q

COMPACT BONE IS ON THE PERIPHERY VS SPONGY
BONE IN THE

A

MIDDLE OF THE BONE

84
Q

not a static tissue.
a dynamic tissue and it continues to be
remodeled throughout life.
- But not in a very fast manner, only in a slow
manner

  • It will be faster for children, not in adults

❖ In adults, it has to undergo resorption in the osteoblast before you can lay down new bone in the osteoblast

A

BONE

85
Q

The histologic features of Trabeculae:

A

✓ also lined with osteoblast
✓ is lined with bone spicule necessary for weight
transfer, source of quick bone absorption

86
Q

similar to Lamellar Bone or Compact Bone, the
______________________ bone also has
canaliculi but is arrange in a hair-like fashion within the trabeculae

also has its own cells of osteoclast that participates in
bone resorption

A

Sponge (cancellous/medullary)

87
Q

a tissue for red blood
cells as well as white blood cells

A

Hematopoietic tissue

88
Q

As an individual grow older, the red marrow that
produces red blood cell eventually reduces in number and it’s going to be replaced by ___________

A

fatty tissue or yellow marrow

89
Q

✓ Undergo bone remodeling
✓ In kids, it is normal
✓ The presence of this may be an indication of
a fracture in adults
✓ A red flag in adults, as it can be found in lesions

✓ Malignancies in bodies can be shown as a woven
bone (e.g., osteosarcoma- a bone forming tumor
creating woven bone)

A

Woven Bone

90
Q

-forms during development and be remodeled by lamellar bone

-ultra primary or immature bone and the one form near the ossification process

-collagen fibers are unorganized
-osteocytes are scattered about the bony matrix

A

Woven (primary, immature) bone

91
Q

❖ most compact and spongy bone in the embryo initially form as a __________

❖ in the adults, ________________ is form in limited areas like sites of healing bone and alveolar processes of the maxilla and mandible

A

woven bone

92
Q

Bone tissue that forms through remodeling the woven bone

-Collagen fibers are well-organized
-Osteocytes are regularly arranged and spaced throughout the bony matrix

❖ In between bony matrix found in adult are the
compact and spongy bone

A

Lamellar (secondary, mature) bone

93
Q

release by the parathyroid gland and inhibits osteoblast by producing the bony matrix

  • but it stimulates the osteoblast (the derivatives of monocytes) via stimulating factor

which increases bone reabsorption by the osteoblast,
ultimately results in elevation of calcium in the body

A

PTH

94
Q

released by the parafollicular cells in the thyroid
gland

-inhibits the osteoblast thus no bone reabsorption
-lead to decrease in blood calcium

A

Calcitonin

95
Q

These 2 major hormones regulate bone remodeling and blood calcium level

A

Parathyroid hormone and calcitonin

96
Q

2 forms of bone formation

A
  • Membranous (intramembranous) ossification
  • Endochondral ossification
97
Q
  • Bone formation from the cartilage
  • Utilizes the hyaline cartilage model as mold, which is then replaced by bony tissue
  • long bones form in this manner.
  • As the cartilage model grows, a bony collar forms
    around the future diaphysis and blood vessel,
A

Endochondral Ossification

98
Q

disc of hyaline that remains in endochondral
ossification

  • closes 20-25 yrs old
  • epiphyseal plate necessary for bone elongation
  • produces hyaline cartilage
A

Growth plate

99
Q

The rate of hyaline cartilage replacement with bone
tissue ___________ in adolescence until entire growth plate is calcified

A

increases

100
Q

HORMONAL REGULATION :

A

PTH- Initially stimulates osteoblasts to allow osteoclast to
function thereby also increasing Ca2+
-responsible for activating osteoclast through OSF production
of the Osteoblast.

Calcitonin- inhibits osteoclast function, decreasing blood Ca2

101
Q
  • systemic skeletal bone disease
  • looses bone density
  • increases susceptibility to fracture
  • skeletal deformities due to hormonal imbalance
  • more bone resorption than bone building
A

Osteoporosis

102
Q
A

Physiology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions