Musclular System

Question 1

What is the Study of Muscles?

Answer 1

Myology

Question 2

What characteristics make muscles highly specialized?

Answer 2

Excitability, Contractility, Elasticity

Question 3

Skeletal Muscle

Answer 3

Structure: striated, multinucleated
Function: move and stabalize skeleton
Location: around bones
Control: voluntary

Question 4

Cardiac Muscles

Answer 4

Structure: striated with intercaliated discs
Function: cirrculate blood
Location: heart
Control: involuntary

Question 5

Smooth Muscle

Answer 5

Structure: smooth and spindle shaped
function: controls diameter of passageways, and moves food, urine, and reproductive tract secretions.
Location: around blood vessesl and walls of hollow organs
Control: involuntary

Question 6

Which type of muscle is included in the muscular system?

Answer 6

Skeletal Muscle

Question 7

What attaches skeletal muscles to bone?

Answer 7

Tendons

Question 8

Five major functions of skeletal muscle:

Answer 8

1. produce body movements
2. stabalize body position
3. storing and moving substances in the body
4. heat production
5. store nutrient reserves

Question 9

Layers of connective tissue:

Answer 9

Epimysium- around whole muscle
Perimysium- around muscle fasical
Endomysium- around muscle fiber

Question 10

Where are myosteliite cells found and what is their function?

Answer 10

in endomysium, stem cells that repair damages muscle tissue

Question 11

Muscle fascicle

Answer 11

groups of muscle fibers

Question 12

What makes a Tendon?

Answer 12

extension of connective tissue layers

Question 13

Aponeuroses

Answer 13

flat thick tendon

Question 14

What stem cells fuse to form muscle fibers?

Answer 14

myoblasts

Question 15

What is the sarcolemma and where is it found?

Answer 15

Cell membrane on outside of cell

Question 16

What is sarcoplasm

Answer 16

like cytoplasm

Question 17

Where is the sarcoplasmic reticulum located and what is its function?

Answer 17

the organelle that surrounds myofibril. stores and releases calcium for muscle contraction.

Question 18

Transverse Tubules and their function

Answer 18

network of tubules in sarcolemma used to convey electrical impulses for muscle contraction.

Question 19

Myofibril, what is it composed of and how many are in a muscle fiber?

Answer 19

bundles of proteins myofilaments

Question 20

what are myofilaments and where are they found?

Answer 20

protein filaments responsible for muscle contraction
Actin= thin
myosin= thick

Question 21

What is a sarcomere?

Answer 21

smallest contractile unit of muscle fiber; basic functional unit of muscle fiber

Question 22

atrophy vs. hypertrophy

Answer 22

atrophy= muscle wasting
hypertrophy= muscle increase in size

Question 23

organization of a muscle

Answer 23

epimysium, whole muscle, perimysium, muscle fascicles and fibers, endomysium, sarcolema, muscle fiber, sarcoplasmic reticulum, myofibril, myofilaments

Question 24

z disc

Answer 24

anchor thin filament

Question 25

m line

Answer 25

anchor thick filament

Question 26

a band

Answer 26

contain thick filaments and zone of overlap

Question 27

I band

Answer 27

contain only thin filaments

Question 28

troponin

Answer 28

controls tropomyosin and calcium binds to it

Question 29

tropomyosin

Answer 29

lies in actins groove and acts to block myosin from attaching to actin's active site

Question 30

myosin

Answer 30

motor protein with short rods that have globular heads, forms cross-bridges during contraction

Question 31

Sliding filament mechanism

Answer 31

1. action potential leads to the release of calcium by sarcoplasmic reticulum. calcium binds to troponin producing a change in the orientation of the troponin- tropomyosin complex that exposes the active sites on actin 2. cross-bridges form when myosin heads bind to active sites 3. myosin heads pivots toward the m line actin slides toward m line and sarcomere contracts 4. ATP gives myosin head energy to unattach and re-set

Question 32

Rigor mortis

Answer 32

time period of muscle rigidity following death

Question 33

Neuromusclular junction

Answer 33

synapse between somatic motor neuron and a skeletal muscle fiber

Question 34

presynaptic cell

Answer 34

neuron recieve messege

Question 35

postsynaptic cell

Answer 35

neuron send message

Question 36

synapse

Answer 36

site of communication between nerve cell and another cell

Question 37

motor unit

Answer 37

a somatic motor neuron and all the muscle fibers it innervates

Question 38

motor end plate

Answer 38

region of sarcolemma and opposite of synaptic terminals

Question 39

synaptic terminal

Answer 39

expanded tip of axon at NMJ

Question 40

synaptic cleft

Answer 40

space that separates synaptic terminal from motor end plate

Question 41

physiology at NMJ

Answer 41

1. action potential travels down axon to synaptic terminal 2. opens calcium channels in synaptic terminal which causes a sudden change in the terminal's membrane potential 3. Ach diffuses into synaptic cleft. Ach inds to receptors on surface of sarcolemma at the motor end plate. This increases the sarcolemma's pereability to sodium. Sodium rushes into sarcoplasm 4. sudden rush of sodium into sarcoplams results in an action potential in the sarcolemma.

Question 42

What enzyme breaks down acetylcholine?

Answer 42

Acetylcholinesterase

Question 43

What produces the botulinum toxin and what affect does it have?

Answer 43

caused by bacterium clostridium botulinum. Blocks release of synaptic vesicles at NMJ

Question 44

affects of nerve gas and insecticides

Answer 44

inhibits AChE and causes potentially fatal paralytic convulsions

Question 45

affect of cobra toxin and curare

Answer 45

blocks ACh receptors

Question 46

What three factors are involved in determining how long a muscle contraction will last?

Answer 46

1. duration of neural stimulation 2. number of free calcium ions in sarcoplasm 3. availability of ATP

Question 47

Three ways skeletal muscle fiber tension can be increased

Answer 47

1. changes in sarcomere length 2. stimulus frequency 3. motor unit recruitment

Question 48

which sarcomere length provides the maximum ability to generate tension?

Answer 48

Intermediate fiber resting length

Question 49

What is treppe?

Answer 49

When stimulation occurs immediately after relaxation phase

Question 50

what is wave summation and tetanus?

Answer 50

when stimulus frequency is greater than duration of single twitch

Question 51

what is recruitment?

Answer 51

an increase in the number of active motor units

Question 52

motor unit size and function

Answer 52

size indicates how fine the control of movements will be

Question 53

What are the three sources of ATP in muscle fibers

Answer 53

1. Glycolysis 2. Aerobic metabolism 3. Creatin phosphate

Question 54

Which molecule stores most of the glucose in muscle fibers?

Answer 54

glycogen

Question 55

Which provides the most ATP?

Answer 55

Aerobic metabolism

Question 56

What does excessive pyruvate get converted into?

Answer 56

lactic acid. decreases pH and causes fatigue

Question 57

Slow, fast, and intermediate muscle fibers

Answer 57

Slow: Fatigability= fatugue resistant contraction speed= slow diameter size= 1/2 diameter of fast fibers amount of myoglobin, mitochondria, and blood capillaries= ^ Fast: Fatigabuility= fatigable contraction speed= fast diameter size= large amount of myoglobin, mitochondria, and blood capillaries= low

Question 58

why do fast fibers have a white appearance and slow fibers have a red appearance?

Answer 58

slow more blood flow

Question 59

can you train to increase the effectivness of each fiber?

Answer 59

yes

Question 60

What is muscular dystrophy and myasthenia gravis?

Answer 60

Dystrophy- congenital diseases that produce progressive muscle weakness and deterioration MG- progressive muscular weakness due to loss of acetylcholine receptors at motor end plate.