Physiology Test Ii

Front 1

support protection
movement blood formation
mineral reservoir pH balance detoxification

Back 1

Functions of the skeletal system

Front 2

____ & _____ components are responsible for the major functional characteristics of bone.

Back 2

Collagen and mineral

Front 3

collagen is for_____ strength in bones.

Back 3

flexible strength

Front 4

mineral components is for ______
strength in bones.

Back 4

weight-bearing

Front 5

Bones form through two processes during fetal development...

Back 5

1. Intramembranous ossification
2. Endochondral ossification

Front 6

**Produces flat bones of skull, part of the mandible, & clavicle
**Key points:
---Begins within embryonic mesenchyme at approximately the 8th week of fetal development and is completed by approximately 2 years of age (fontanels close)
---Mesenchymal cells give rise to osteoblasts

Back 6

Intramembranous Ossification

Front 7

--form ossification centers within the collagen membrane
--Internally they form spongy bone
--externally they form compact bone.

Back 7

osteoblasts

Front 8

remodel the bone

Back 8

Osteoclasts

Front 9

**Primary ossification center forms in hyaline cartilage model
--cells of the perichondrium produce a bony collar
--cuts off diffusion of nutrients and hastens their death
**Primary marrow space formed

Back 9

Endochondral Ossification

Front 10

**Begins to form in the epiphyses near time of birth; appears in the proximal epiphysis of the femur, humerus, and tibia approx. 1 month before birth
**Hyaline cartilage remains on joint surface as articular cartilage and at junction of diaphysis & epiphysis (epiphyseal plate)

Back 10

Secondary Ossification Center

Front 11

Which of the following would be true concerning secondary ossification?

A. It begins within the diaphysis of the bone.
B. It only occurs post-natal (after birth).
C. It is responsible for the formation of the flat bones.
D. It begins within mesenchyme.
E. It begins in the epiphyses near time of birth.

Back 11

E. It begins in the epiphyses near time of birth.

Front 12

Bones increase in length by

Back 12

interstitial growth of epiphyseal plate

Front 13

Bones increase in width by

Back 13

appositional growth

Front 14

excessive proliferation of osteoclasts

Back 14

(osteitis deformans)- Paget’s Disease

Front 15

**Short stature but normal-sized head and trunk
--long bones of the limbs stop growing in childhood but other bones unaffected
**Result of spontaneous mutation when DNA is replicated
--mutant allele is dominant

Back 15

Achondroplastic Dwarfism

Front 16

a crystallization process in which ions (calcium, phosphate & others) are removed from blood plasma & deposited in bone tissue

Back 16

Mineralization or Mineral Deposition

Front 17

***abnormal calcification

---may occur in lungs, brain, eyes, muscles, tendons or arteries (arteriosclerosis)
--In soft organs called a calculus (ex. Renal calculi)

Back 17

Ectopic ossification

Front 18

Renal calculi is also known as

Back 18

Kidney stones

Front 19

an abnormal bony growth or projection

Back 19

Bone Spur

Front 20

Process of dissolving bone & releasing minerals into the blood

**performed by osteoclasts “ruffled border”
-hydrogen pumps in the cell membrane secrete hydrogen ions into the space between the osteoclast & the bone
-chloride ions follow by electrical attraction
-hydrochloric acid & a pH of 4 dissolve bone minerals
-an enzyme (acid phosphatase) digests the collagen

Back 20

Mineral Resorption

Front 21

Changes in phosphate concentration have little effect

Changes in calcium can be serious

Back 21

Ion Imbalances

Front 22

deficiency of blood calcium

causes excessive excitability of nervous system leading tomuscle spasms, tremors or tetany
--laryngospasm may cause suffocation

Back 22

hypocalcemia

Front 23

an excess of blood calcium; makes nerves less likely to fire.

Back 23

hypercalcemia

Front 24

_______ homeostasis depends on calcitriol, calcitonin & parathyroid hormone

Back 24

Calcium/phosphate

Front 25

Factors Affecting Bone Growth

Back 25

++20 or more hormones (growth hormone, thyroid hormone, sex hormones), vitamins (D & C), & growth factors
++Bone growth is especially rapid at puberty
--hormones stimulate growth plate
--adolescent girls grow faster than boys & reach their full height earlier (estrogen has stronger effect)
--males grow for a longer time
++Growth ceases when epiphyseal plate “closes”
--anabolic steroids may cause premature closure of growth plate producing short adult stature

Front 26

a break caused by abnormal trauma to a bone
EX. car accident, fall, athletics, etc

Back 26

Stress fracture

Front 27

a break in a bone weakened by some other disease
EX. bone cancer or osteoporosis

Back 27

Pathological fracture

Front 28

Healing of Fractures
Normally healing takes 8 - 12 weeks (longer in elderly)

Lisr the stages:

Back 28

1. fracture hematoma
2. granulation tissue
3. callus formation
4. remodeling

Front 29

broken vessels form a blood clot

Back 29

Stage 1

Front 30

fibrous tissue formed by fibroblasts & infiltrated by capillaries

Back 30

Stage 2

Front 31

soft callus of fibrocartilage replaced by hard callus of bone in 6 weeks

Back 31

Stage 3

Front 32

occurs over next 6 months as spongy bone is replaced with compact bone

Back 32

Stage 4

Front 33

Bones lose mass & become brittle due to loss of both organic matrix & minerals
--risk of fracture of hip, wrist & vertebral column
--lead to fatal complications such as pneumonia
--widow’s (dowager’s) hump is deformed spine

Back 33

Osteoporosis (porous bone)

Front 34

Postmenopausal women at greatest risk because of decreased estrogen (estrogen inhibits the action of PTH)
--by age 70, average loss is 30% of bone mass

Other conditions that lower estrogen:

Back 34

removal of ovaries
extreme exercise to the point menstrual flow stops
anorexia nervosa
cigarette smoking

Front 35

Hypocalcemia can result from any of the following except

A. lactation.
B. a vitamin D deficiency.
C. excessive secretion of parathyroid hormone.
D. severe diarrhea.
E. excessive secretion of calcitonin.

Back 35

C. excessive secretion of parathyroid hormone.

Front 36

Function of joints

Back 36

Binds the bones of the skeletal system together

Allows skeleton to be mobile

Front 37

Ligaments

Back 37

*Unite bones
*Help direct movement
*Prevent excessive or undesirable motion
*Disadvantage- ligaments stretch and stay stretched

Front 38

Most important stabilizing factor is the tendons that cross the joint to join muscle to bone. These tendons are taught when muscles are well toned.

Back 38

Muscle tone

Front 39

Synovial Joints (freely movable)

???-squeezes synovial fluid from cartilages when a joint is compressed by movement

Back 39

Weeping lubrication

Front 40

Range of Motion varies greatly from one type of joint to another and is measured with

Back 40

goniometer

Front 41

Factors affecting ROM andjoint stability

Back 41

-structure & action of themuscles
-structure of the articular surfaces
-strength and tautness of ligaments, tendons & capsule

Front 42

______ keep track of joint position & muscle tone

Back 42

proprioceptors

Front 43

A _____ is a rigid object that rotates around a fixed point called a fulcrum

Back 43

lever

Joints function as levers

Front 44

Mechanical Advantage s calculated from the length of the effort arm divided by the length of the resistance arm

Back 44

<1 = Low power, high speed
>1 = High power, low speed

Front 45

**Has fulcrum in the middle between effort & resistance
**Atlantooccipital joint lies between the muscles on the back of the neck and the weight of the face
---loss of muscle tone occurs when you nod off in class

Back 45

First-Class Lever

Front 46

**Has resistance in the middle between fulcrum & effort
**Resistance from the muscle tone of the temporalis muscle lies between the jaw joint and the pull of the diagastric muscle on the chin as it opens the mouth quickly
--upside down example relative to wheelbarrow illustration

Back 46

Second-Class Lever

Front 47

**Has the effort in the middle between the resistance & the fulcrum
{most joints of the body}
**The effort applied by the biceps muscle is applied to the forearm between the elbow joint and the weight of the hand and the forearm

Back 47

Third-Class Lever

Front 48

Trauma induced HOMEOSTATIC IMBALANCES OF JOINTS

Back 48

1. Sprain
2. Dislocation (luxation)

Front 49

Inflammatory and/or degenerative HOMEOSTATIC IMBALANCES OF JOINTS

Back 49

1. Bursitis (septic bursitis)
2. Tendonitis

Front 50

A broad term for pain and inflammation
Both acute and chronic forms

Back 50

ARTHRITIS

Front 51

Acute forms of arthritis:

Back 51

Septic Arthritis
- caused by a bacterial invasion of a joint, resulting in inflammation of the synovial lining

Front 52

chronic forms of arthritis:

Back 52

> Osteoarthritis
> Adult Rheumatoid Arthritis
> Gouty Arthritis

Front 53

-chronic progressive disorder causing deterioration of the articular cartilage of joints and the formation of reactive new bone at the margins and subchondral areas of the joints
- referred to as degenerative joint disease
- usually begins in middle age and becomes progressively worse
- can either be caused by
1)normal wear and tear of aging or
2) genetically inherited
- more cartilage is destroyed than replaced
- bone becomes exposed and thickens, bone spurs form
- sound of grinding or roughed bony articulating surfaces
- usually treated with aspirin; severe cases may require surgery

Back 53

Osteoarthritis

Front 54

sound of grinding or roughed bony articulating surfaces

Back 54

crepitus

Front 55

a chronic, systemic, inflammatory disease that is actually an auto immune disorder where the body's own immune system attacks its tissues through destructive enzymes released through the immune system
- cause is not known
- strikes females 3X more than males, most often between 30 - 40 years of age
- fatigue, joint tenderness, stiffness
- characterized by flare-ups and remissions

Back 55

Adult Rheumatoid Arthritis

Front 56

a metabolic disease caused by the accumulation of uric acid
- usually affects the base of the big toe
- more common in males and may be genetically linked
- if untreated bones can fuse
- alter diet and drug treatment

Back 56

Gouty Arthritis

Front 57

- inflammation and thickening of the synovial membrane
- swelling due to the accumulation of synovial fluid
- scar tissue forms which may fuse bones as it ossifies (ankylosis)
- administer anti-inflammatory drugs

Back 57

Rheumatoid Arthritis

Front 58

__________ is a degenerative joint disease that apparently results from a combination of aging, irritation of the joints, and normal wear and tear.

A. Adult rheumatoid arthritis
B. Osteoporosis
C. Tendonitis
D. Osteoarthritis
E. Luxation

Back 58

D. Osteoarthritis

Front 59

What do we mean by “excitable cells”?

Back 59

These are cells that self-generate electrochemical impulses and transmit signals along their membrane.

Front 60

_____ & _______ cells are excitable cells

Back 60

muscle and nerve

Front 61

All cells have a _______ that is due to an unequal distribution of ions.

Back 61

resting membrane potential (RMP)

Front 62

The concentration of K+ is higher inside the cell and potassium constantly “leaks out” down its concentration gradient. These helps keep the cell ________.

Back 62

electronegative

Front 63

Because there is a “+” charge on the ECF and a “-” charge on the ICF, at rest the membrane is _____.

Back 63

polarized

Front 64

In nerve and muscle cells, the resting membrane potential changes when the cells receive a _______.

Back 64

stimulus

Front 65

____is more concentrated outside of cell (ECF) and ____ more concentrated inside the cell (ICF)

Back 65

Na+ - ECF

K+ - ICF

Front 66

The conducting cell of the nervous system is

Back 66

the neuron

Front 67

Neurons are stimulated at dendrites by a number of types of stimuli such as

Back 67

- the binding of a ligand (chemical messengers).
-mechanical distortion (pressure).
-light and sound.

Front 68

Na+ ions diffuse rapidly from the ECF into the cell. This makes the outside of the less positive and the inside of the cell more positive. The area of cell membrane is _______.

Back 68

depolarized

Front 69

If the stimulus is strong enough the depolarization will reach the area of the neuron called the ____ or _____.

Back 69

axon hillock or trigger zone

Front 70

If the sodium influx is great enough at the trigger zone, a long-distance signal that travels down the axon will be initiated. This is is an ___ or ____.

Back 70

action potential or nerve impulse

Front 71

--More dramatic change in membrane produced where high density of voltage-gated channels occur
-Reach threshold potential(-55mV)
-Voltage-gated Na+ channels open (Na+ enters for depolarization)
-Passes 0 mV & Na+ channels close (peaks at +35)
-K+ gates fully open (K+ leaves) produces repolarization

Back 71

Action Potentials

Front 72

Negative overshoot produces

Back 72

hyperpolarization

Front 73

-follows an all-or-none law and thus are not graded
-are nondecremental (do not get weaker with distance)
-are irreversible (once started goes to completion and can not be stopped)

Back 73

Characteristics of action potential

Front 74

Period of resistance to stimulation

Back 74

The Refractory Period

Front 75

--as long as Na+ gates are open
--no stimulus will trigger AP

Back 75

Absolute refractory period

Front 76

--as long as K+ gates are open
--only especially strong stimulus will trigger new AP

Back 76

Relative refractory period

Front 77

______ is a rest period where a neuron cannot respond to another stimulus no matter how strong the stimulus.
A. absolute refractory period
B. relative refractory period
C. synaptic cleft
D. IPSP E. EPSP

Back 77

A. absolute refractory period

Front 78

Action potential in trigger zone begins chain reaction that travels to end of axon

Back 78

Impulse Conduction in Unmyelinated Fibers

Front 79

--Faster than the continuous or “chain reaction” type of conduction
--Voltage-gated Na+ and K+ channels are concentrated at the Nodes of Ranvier.
--Impulse seems to “jump” from node to node.

Back 79

Saltatory Conduction in Myelinated Fibers

Front 80

Speed of signal transmission along nerve fibers depends on

Back 80

diameter of fiber & presence of myelin

-small, unmyelinated = 2.0 m/sec
-small, myelinated = 15.0 m/sec
-large, myelinated = up to 120 m/sec

Front 81

Neurons communicate with

Back 81

*other neurons.
*glands.
*muscle cells

Front 82

The functional area of contact is the ___.
The electrical signal cannot cross it and is converted into a chemical signal.

Back 82

synapse

Front 83

The chemical signal is carried by ___ released by the presynaptic neuron.

Back 83

neurotransmitters

Front 84

Presynaptic neurons have synaptic __a__ with neurotransmitter and postsynaptic have __b___.

Back 84

a. vesicles

b. receptors

Front 85

Types of Neurotransmitters

What are the 3 major categories?

Back 85

1. Acetylcholine
2. Amino acid neurotransmitters
3. Monoamines

Front 86

Monoamines

Name the catecholamines.

Back 86

epinephrine
norepinephrine
dopamine

Front 87

Monoamines

Name the indolamines.

Back 87

serotonin
histamine

Front 88

Gases such as ______ can also function as neurotransmitters.

Back 88

nitric oxide

Front 89

Modify actions of neurotransmitters
-gut-brain peptides cause
food cravings

Back 89

Neuropeptide

Front 90

Why are these neuropeptides used:
1. Substance-P-
2. Enkephalin-
3. B-endorphin-
4. Cholecystokinin -

Back 90

Substance-P- feel pain
Enkephalin & B-endorphin- Natural opiates (analgesis pain killers)
Cholecystokinin - appetite (stomach)

Front 91

Cholinergic synapse produces ionotropic effect

Back 91

Ionic Synaptic Transmission

Front 92

ACh receptors trigger opening of Na+ channels producing local potential

Back 92

postsynaptic potential

Front 93

Neurotransmitter uses 2nd messenger such as cyclic AMP to alter metabolism of postsynaptic cell

Back 93

Metabotrophic Synapse Transmission

Front 94

Mechanisms to turn off stimulation

Back 94

1.diffusion
2.monoamine oxidase
3.acetylcholinesterase

Front 95

Cessation & Modification of Signal
1. diffusion of neurotransmitter away from synapse into ECF where astrocytes return it to the neurons
2. synaptic knob reabsorbs amino acids and monoamines by

Back 95

endocytosis & breaks them down with monoamine oxidase
3. acetylcholinesterase degrades ACh in the synaptic cleft
---choline reabsorbed & recycled

Front 96

Name the Postsynaptic Potentials.

Back 96

* Excitatory postsynaptic potentials
* Inhibitory postsynaptic potentials
* ACh & norepinephrine vary depending on cell

Front 97

**positive voltage change make postsynaptic cell more likely to fire
-result from Na+ flowing into the cell

Back 97

EPSP

Front 98

What are excitatory neurotransmitters?

Back 98

glutamate & aspartate

Front 99

Modify actions of neurotransmitters
-gut-brain peptides cause
food cravings

Back 99

Neuropeptide

Front 100

Why are these neuropeptides used:
1. Substance-P-
2. Enkephalin-
3. B-endorphin-
4. Cholecystokinin -

Back 100

Substance-P- feel pain
Enkephalin & B-endorphin- Natural opiates (analgesis pain killers)
Cholecystokinin - appetite (stomach)

Front 101

Cholinergic synapse produces ionotropic effect

Back 101

Ionic Synaptic Transmission

Front 102

ACh receptors trigger opening of Na+ channels producing local potential

Back 102

postsynaptic potential

Front 103

Neurotransmitter uses 2nd messenger such as cyclic AMP to alter metabolism of postsynaptic cell

Back 103

Metabotrophic Synapse Transmission

Front 104

Mechanisms to turn off stimulation

Back 104

1.diffusion
2.monoamine oxidase
3.acetylcholinesterase

Front 105

Cessation & Modification of Signal
1. diffusion of neurotransmitter away from synapse into ECF where astrocytes return it to the neurons
2. synaptic knob reabsorbs amino acids and monoamines by

Back 105

endocytosis & breaks them down with monoamine oxidase
3. acetylcholinesterase degrades ACh in the synaptic cleft
---choline reabsorbed & recycled

Front 106

Name the Postsynaptic Potentials.

Back 106

* Excitatory postsynaptic potentials
* Inhibitory postsynaptic potentials
* ACh & norepinephrine vary depending on cell

Front 107

**a positive voltage change causing postsynaptic cell to be more likely to fire
-result from Na+ flowing into the cell

Back 107

EPSP

Front 108

What are excitatory neurotransmitters?

Back 108

glutamate & aspartate

Front 109

**a negative voltage change causing postsynaptic cell to be less likely to fire (hyperpolarize)
--result of Cl- flowing into the cell or K+ leaving the cell

Back 109

IPSP

Front 110

What are the inhibitory neurotransmitters?

Back 110

glycine & GABA

Front 111

Epinephrine, norepinephrine and dopamine are classified as:
A.Indolamines B.Catecholamines
C.Acetylcholine mimics
D. neuropeptides

Back 111

B. Catecholamines

Front 112

In order for ____ muscle to contract, it must be excited but a motor neuron.

Back 112

skeletal

Front 113

-Sarcolemma
-Sarcoplasm
-Sarcoplasmic reticulum

Back 113

Skeletal Muscle Fibers

Front 114

Sarcolemma has tunnel-like infoldings or ________ that penetrate the cell.

Back 114

transverse (T) tubules

Front 115

bundles of parallel protein microfilaments called myofilaments

Back 115

myofibrils

Front 116

______has transverse (T) tubules that penetrate the cell

--carry electric current to cell interior

Back 116

Sarcolemma

Front 117

______is filled with myofibrils

--glycogen for stored energy &
myoglobin binding oxygen

Back 117

Sarcoplasm

Front 118

________ is series of dilated, calcium
storage sacs

Back 118

Sarcoplasmic reticulum

Front 119

*Made of 200 to 500 myosin molecules (contractile proteins)
*Arranged in a bundle with heads directed outward in a spiral array around the bundled tails

Back 119

Thick Filaments

Front 120

2 entwined golf clubs

Back 120

contractile proteins

Front 121

*Two strands of fibrous (F) actin (contractile proteins) intertwined with subunits of globular (G) actin with an active site.

Back 121

Thin Filaments

Front 122

Thin filament groove holds _____ molecules blocking the active sites, with smaller, calcium-binding _____ molecules

Back 122

tropomyosin

troponin

**both are regulatory protein**

Front 123

Muscle cells shorten because their ____ shorten
**Notice neither thick nor thin filaments change length during shortening,just their overlap

Back 123

sarcomeres

Front 124

Synapse is region where nerve fiber makes a functional contact with its target cell ____

Back 124

Neuromuscular Junctions (NMJ)

Front 125

Neurotransmitter released from nerve fiber causes stimulation of muscle cell

Back 125

acetylcholine

Front 126

What are the components of synapse?

Back 126

--synaptic knob
--motor end plate

Front 127

___ is swollen end of nerve fiber which
contains vesicles filled with ACh

Back 127

synaptic knob

Front 128

___is region of muscle cell surface which has ACh receptors that bind ACh released from nerve

Back 128

motor end plate

Front 129

____ is enzyme that breaks down ACh & causesrelaxation.

Back 129

Acetylcholinesterase

Front 130

Pesticides contain cholinesterase inhibitors that bind to acetylcholinesterase & prevent it from degrading ACh
ex:Tetanus or lockjaw- caused
by toxin of Clostridium bacteria

Back 130

Spastic paralysis

Front 131

_____ with limp muscles unable to contract caused by curare that competes with ACh

Back 131

Flaccid paralysis

Front 132

Skeletal Muscle Contraction:

Excitation (steps 1 & 2)

Back 132

Nerve signal stimulates voltage-gated calcium channels that result in exocytosis of synaptic vesicles containing ACh

Front 133

Skeletal Muscle Contraction:

Excitation (steps 3 & 4)

Back 133

Binding of ACh opens Na+ and K+ channels resulting in an end-plate potential (EPP)

Front 134

Skeletal Muscle Contraction:

Excitation (step 5)

Back 134

Voltage change in end-plate region (EPP) opens nearby voltage-gated channels in plasma membrane producing an action potential

Front 135

Skeletal Muscle Contraction:

Excitation-Contraction Coupling
(steps 6&7)

Back 135

Action potential spreading over sarcolemma reaches T tubules -- voltage-gated channels open in
T tubules causing calcium gates to open in SR

Front 136

Skeletal Muscle Contraction:

Excitation-Contraction Coupling
(steps 8&9)

Back 136

Calcium release causes binding of myosin to active sites on actin

Front 137

Skeletal Muscle Contraction:

Contraction (steps 10 & 11)

Back 137

Myosin head with an ATP molecule bound to it can form a cross-bridge. ATP is broken down.

Front 138

Skeletal Muscle Contraction:

Contraction (steps 12 & 13)

Back 138

Power stroke shows myosin head releasing the ADP & phosphate and flexing as it pulls thin filament along -- binding of more ATP releases head from the thin filament

Front 139

Skeletal Muscle Contraction:

Relaxation (steps 14 & 15)

Back 139

Stimulation ceases and acetylcholinesterase removes ACh from receptors so stimulation of the muscle cell ceases

Front 140

Skeletal Muscle Contraction:

Relaxation (step 16)

Back 140

**Active transport pumps calcium back into SR where it binds to calsequestrin
**ATP is needed for muscle relaxation as well as muscle contraction

Front 141

Skeletal Muscle Contraction:

Relaxation (steps 17 & 18)

Back 141

Loss of calcium from sarcoplasm results in hiding of active sites and cessation of the production or maintenance of tension

Front 142

Stiffening of the body beginning 3 to 4 hours after death -- peaks at 12 hours after death & diminishes over next 48 hours is ______.

Back 142

Rigor Mortis

Front 143

Group of hereditary diseases in which skeletal muscles degenerate & are replaced with adipose

Back 143

Muscular Dystrophy

Front 144

a protein that links actin filaments to cell membrane

Back 144

dystrophin

Front 145

Autoimmune disease where antibodies attack NMJ and bind ACh receptors together in clusters
--less and less sensitive to ACh

Back 145

Myasthenia Gravis

Front 146

Signs & Symptoms of Myasthenia Gravis

Back 146

*drooping eyelids and double vision
*difficulty swallowing
*weakness of the limbs
*respiratory failure

Front 147

Treatment for Myasthenia Gravis

Back 147

Cholinesterase inhibitors
Thymus removal
Immunosuppressive agents

Front 148

Types of Smooth Muscle

Back 148

--Multiunit smooth muscle

--Single-unit smooth muscle

Front 149

--in largest arteries, iris, pulmonary air passages, arrector pili muscles

--independent contraction

Back 149

Multiunit smooth muscle

Front 150

-in most blood vessels & viscera as circular & longitudinal muscle layers
-electrically coupled by gap junctions
-large number of cells contract as a unit

Back 150

Single-unit smooth muscle

Front 151

Stimulation of Smooth Muscle

Back 151

Involuntary & contracts w/o nerve stimulation
**hormones, CO2, low pH, stretch, O2 deficiency
pacemaker cells GI tract- autorhythmic

Front 152

Calcium triggering contraction is __
-Ca enters cell
-calcium ion binds to calmodulin
-power stroke

Back 152

extracellular

Front 153

Ca enters cell through channels triggered by :

Back 153

voltage
hormones
neurotransmitters
stretching of the cell

Front 154

What is calmodulin?

Back 154

A calcium-binding protein

Front 155

Explain power stroke

Back 155

Calcium/calmodulin complex activates myosin light-chain kinase which activates the myosin head with ATP to bind actin

Front 156

Smooth Muscle uses l0-300 times less ATP to maintain the same tension

Define muscle tone & vasomotor tone

Back 156

muscle tone- latch-bridge mechanism maintains tetanus

vasomotor tone- keeps arteries in state of partial contraction

Front 157

List responses to Stretch

Back 157

--Muscle response
--Stress-relaxation response
--Plasticity

Front 158

Stretch opens mechanically-gated calcium channels causing
_______.

Back 158

Muscle response

Front 159

______ necessary for hollow organs that gradually fill (urinary bladder)
**when stretched, tissue briefly
contracts then relaxes

Back 159

Stress-relaxation response

Front 160

_____ is ability to adjust tension to degree of stretch such as empty bladder is not flabby

Back 160

Plasticity

Front 161

What provides the energy to power muscle contraction?

Back 161

Oxygen

[Myoglobin provides oxygen for limited term aerobic respiration]

Front 162

What happens when oxygen supply can not be maintained, as in a short, intense exercise (100 m dash)?

Back 162

Most ATP demand is met by transferring Pi from other molecules
known as phosphagen system.

Front 163

Phosphagen system uses what 2 enzymes to generate ATP in the absence of oxygen

Back 163

myokinase & creatine kinase

Front 164

____ transfers Pi groups from one ADP to another, converting the latter to ATP

Back 164

myokinase

Front 165

___ obtains Pi groups from creatine phosphate and donates them to ADP to make ATP

Back 165

creatine kinase

Front 166

Short-Term Energy
Once phosphagen system is exhausted, ______ (anaerobic) produces ATP for 30-40 seconds of maximum activity

Back 166

glycogen-lactic acid system

[muscles obtain glucose from blood & stored glycogen]

Front 167

Note: Long-Term Energy
After 40 seconds of exercise, respiratory & cardiovascular systems begin to deliver enough oxygen for aerobic respiration

Back 167

ATP production keep pace w/demand
**Limits are set by depletion of glycogen & blood glucose, loss of fluid and electrolytes through sweat
--little lactic acid buildup occurs

Front 168

_____is progressive weakness & loss of contractility from prolonged use

Back 168

Fatigue

Front 169

List the causes of Fatigue

Back 169

--ATP synthesis declines as glycogen is consumed
--ATP shortage causes sodium-potassium pumps to fail to maintain membrane potential & excitability

Front 170

{cont'd} Causes of Fatigue
--lactic acid lowers pH of sarcoplasm
inhibiting enzyme function
--motor nerve fibers use up their
acetylcholine

Back 170

{cont'd} Causes of Fatigue
--accumulation of extracellular K+ lowers the membrane potential & excitability

Front 171

Ability to maintain high-intensity exercise is determined by maximum oxygen uptake
-Depend on supply of organic nutrients
-fatty acids, amino acids & glucose

Back 171

Endurance

Front 172

_____ is proportional to body size, peaks at age 20, is larger in trained athlete & males

Back 172

VO2 max

Front 173

Need to breathe heavily after strenuous exercise
-typically about 11 liters extra is
consumed

Back 173

Oxygen Debt

Front 174

Purposes for extra oxygen:

Back 174

--replace O2 reserves (myoglobin,
hemoglobin, in lungs & in plasma)
--replenishing the phosphagen sys.
--reconverting lactic acid to glucose
--serving the elevated metabolic rate

Front 175

- Linked to each other at intercalated
discs
-Autorhythmic due to pacemaker cell
-Uses aerobic respiration almost
exclusively

Back 175

Cardiac Muscle

Front 176

In cardiac muscle,
--________ allow cells to stimulate
their neighbors
--Ca+2 from extracellular fluid

Back 176

electrical gap junctions

Front 177

In cardiac muscle, large _____make it resistant to fatigue

Back 177

mitochondria

Front 178

The role of calmodulin in smooth muscle is
A. to bind calcium ions.
B. to hydrolyze ATP.
C. to form cross-bridges w/thin myofilaments.

Back 178

A. to bind calcium ions.

Front 179

Oxygen debt is the amount of extra oxygen needed after an exercise to do all of the following except
A) oxidize lactic acid.
B) lower the metabolic rate to a resting level.
C) replenish the reserves of creatine phosphate.

Back 179

B) lower the metabolic rate to a resting level.