Action potential

Question 1

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.

Answer 1

diffusion of potassium ions

Question 2

The Resting Membrane Potential Is Established by the :

Answer 2

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

Question 3

high ratio of potassium ions inside
to outside

Answer 3

35 : 1

Question 4

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

Answer 4

94 millivolts.

Question 5

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 _________

Answer 5

+61 millivolts

Question 6

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

Answer 6

The Goldman Equation

Question 7

sodium potassium pump transport :

Answer 7

3 sodium to the outside
2 potassium into the cell

continual loss of positive ions inside the membrane

further negativity of about -4 millivolts

Question 8

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

Answer 8

100 times

Question 9

when u talk about membrane potential, consider the:

Answer 9

• concentration and charge of ions
• permeability of cells

Question 10

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.

Answer 10

action potentials

Question 11

NEURONAL ACTION POTENTIAL stages:

Answer 11

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

Question 12

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

Answer 12

Resting Stage

Question 13

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.

Answer 13

DEPOLARIZATION STAGE

Question 14

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.

Answer 14

Repolarization Stage

Question 15

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.

Answer 15

Neuronal signals

Question 16

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

Answer 16

Voltage-gated sodium channels

Question 17

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

Answer 17

voltage-gated sodium channels

Question 18

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

Answer 18

sodium-potassium pump
sodium-potassium leak channels

Question 19

SUMMARY OF THE EVENTS THAT CASUSES THE
ACTION POTENTIAL

Answer 19

1. Resting State
2. Onset of Action Potential
3. End of Action Potential

Question 20

• 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.

Answer 20

Resting State

Question 21

• 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

Answer 21

Onset of Action Potential

Question 22

End of Action Potential

Answer 22

• Return to a resting membrane potential state
• potassium channels are closed back to its original
  state
• It only happens after a delay

Question 23

-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

Answer 23

POSITIVE FEEDBACK CYCLE.

Question 24

ACTION POTENTIAL DOES NOT OCCUR UNTIL
THRESHOLD POTENTIAL HAS BEEN REACHED

Answer 24

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

Question 25

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

Answer 25

threshold potential

Question 26

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

Answer 26

After action potential is initiated, sodium ion channel are INACTIVATED

Question 27

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

Answer 27

original resting membrane potential

Question 28

2 Things Presends:

Answer 28

1. Absolute Refractory Period 2. Relative Refractory Period

Question 29

- action potential cannot be elicited - Around 2500 impulses per second are transmitted

Answer 29

Absolute Refractory Period

Question 30

- allows refractory period is stronger than normal stimulus to excite nerve fiber. (for action potential to be initiated)

Answer 30

Relative Refractory Period

Question 31

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

Answer 31

PROPAGATION

Question 32

Transmission along neuron or muscles is called _______ (Undergoes an all-or-nothing principle)

Answer 32

neuronal or muscular impulse

Question 33

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

Answer 33

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

Question 34

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

Answer 34

problem in sodium channel pump

Question 35

Large Nerve Fibers Are Myelinated and Small Ones Are

Answer 35

Unmyelinated

Question 36

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

Answer 36

Schwann cells (sphingomyelin)

Question 37

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

Answer 37

nodes of Ranvier

Question 38

the membrane of the axons is used for conduction of

Answer 38

action potential

Question 39

“Saltatory” Conduction Occurs in

Answer 39

Myelinated Fibers

Question 40

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

Answer 40

Saltatory

Question 41

Saltatory conduction is of value for two reasons:

Answer 41

Increased velocity. Energy conservation.

Question 42

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

Answer 42

Increased velocity.

Question 43

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

Answer 43

40%

Question 44

- changes in ions require energy in the form of ATP - Saltatory conduction conserves energy for axon.

Answer 44

Energy Conservation

Question 45

Conduction Velocity Is Greatest in

Answer 45

Large, Myelinated Nerve Fibers. -the velocity increases with the fiber diameter in myelinated fibers (in unmyelinated, square root increase only)

Question 46

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

Answer 46

unmyelinated and myelinated

Question 47

electrical to chemical using _____ in contraction of muscle

Answer 47

calcium ions

Question 48

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

Answer 48

saltatory conduction

Question 49

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)

Answer 49

Bones

Question 50

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.

Answer 50

myofibril

Question 51

Muscle contraction and relaxation is very dependent on

Answer 51

ATP

Question 52

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

Answer 52

cartilage

Question 53

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

Answer 53

cartilage

Question 54

__________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.

Answer 54

Osteoarthritis

Question 55

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

Answer 55

20-25

Question 56

3 types of cartilage:

Answer 56

1. Hyaline Cartilage 2. Elastic Cartilage 3. Fibrocartilage

Question 57

where the cartilage is residing

Answer 57

Lacuna

Question 58

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

Answer 58

extracellular matrix

Question 59

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

Answer 59

Hyaline cartilage

Question 60

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

Answer 60

Chondrocytes

Question 61

fibers in pinna of the external ear

Answer 61

Elastic Cartilage

Question 62

Firm, solid tissue that resembles dense connective tissue Pubic symphysis, annulus fibrosus of intervertebral discs, menisci

Answer 62

Fibrocartilage

Question 63

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.

Answer 63

active diffusion

Question 64

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

Answer 64

Growth of the cartilage

Question 65

TWO TYPES OF GROWTH IN THE CARTILAGE

Answer 65

1. Appositional growth 2. Interstitial growth

Question 66

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.

Answer 66

Appositional growth

Question 67

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

Answer 67

Interstitial growth

Question 68

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

Answer 68

Isogenous cells

Question 69

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

Answer 69

Osteoprogenitors

Question 70

Active: Cuboidal to columnar with basophilic cytoplasm and euchromatic nuclei and distinct nucleoli b. Inactive: Squamous Secrete osteoid Innermost layer of periosteum; endosteum

Answer 70

Osteoblasts

Question 71

convert mechanical to chemical stimulus.

Answer 71

Mechanotransduction

Question 72

Osteoblasts encased in calcified matrix mature and become osteocytes Maintain bony matrix; mechanotransduction Main cell body in lacunae, cell processes in canaliculi

Answer 72

Osteocytes

Question 73

Large, multinucleated macrophage derivative Howship lacunae

Answer 73

Osteoclasts

Question 74

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

Answer 74

Periosteum

Question 75

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

Answer 75

Endosteum

Question 76

it is where blood is produce

Answer 76

Marrow space

Question 77

Mechanical support, protection, weight transfer, mineral storage Outer surfaces of the bones

Answer 77

Compact bone

Question 78

Weight transfer, quick mineral turnover Inner portion of the bones

Answer 78

Sponge bone

Question 79

Site of blood formation and fat storage, lighten the weight of the bone Spaces in between the sponge bone TRABECULAE

Answer 79

Marrow space

Question 80

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

Answer 80

compact bone

Question 81

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

Answer 81

COMPACT BONES

Question 82

✓ 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

Answer 82

SPONGE (CANCELLOUS/MEDULLARY) BONE

Question 83

COMPACT BONE IS ON THE PERIPHERY VS SPONGY BONE IN THE

Answer 83

MIDDLE OF THE BONE

Question 84

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

Answer 84

BONE

Question 85

The histologic features of Trabeculae:

Answer 85

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

Question 86

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

Answer 86

Sponge (cancellous/medullary)

Question 87

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

Answer 87

Hematopoietic tissue

Question 88

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 ___________

Answer 88

fatty tissue or yellow marrow

Question 89

✓ 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)

Answer 89

Woven Bone

Question 90

-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

Answer 90

Woven (primary, immature) bone

Question 91

❖ 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

Answer 91

woven bone

Question 92

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

Answer 92

Lamellar (secondary, mature) bone

Question 93

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

Answer 93

PTH

Question 94

released by the parafollicular cells in the thyroid gland -inhibits the osteoblast thus no bone reabsorption -lead to decrease in blood calcium

Answer 94

Calcitonin

Question 95

These 2 major hormones regulate bone remodeling and blood calcium level

Answer 95

Parathyroid hormone and calcitonin

Question 96

2 forms of bone formation

Answer 96

* Membranous (intramembranous) ossification * Endochondral ossification

Question 97

* 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,

Answer 97

Endochondral Ossification

Question 98

disc of hyaline that remains in endochondral ossification * closes 20-25 yrs old * epiphyseal plate necessary for bone elongation * produces hyaline cartilage

Answer 98

Growth plate

Question 99

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

Answer 99

increases

Question 100

HORMONAL REGULATION :

Answer 100

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

Question 101

* systemic skeletal bone disease * looses bone density * increases susceptibility to fracture * skeletal deformities due to hormonal imbalance * more bone resorption than bone building

Answer 101

Osteoporosis