Lecture 4

Question 1

isometric contraction

Answer 1

length of the muscle does not change

Question 2

isotonic contraction

Answer 2

length of muscle does change, tension remains the same

Question 3

concentric

Answer 3

the muscle gets shorter

Question 4

eccentric

Answer 4

muscle gets longer

Question 5

What are the basics for naming muscles?

Answer 5

Shape 
Function 
Origin insertion 
Relative size 
Fiber Arrangement 
Location

Question 6

Types of fiber arrangements

Answer 6

Straight 
Fusiform 
Unipennate 
Bipennate 
Multipennate

Question 7

What helps to determine what a muscle contraction does?

Answer 7

What a muscle is attached to
Which end of the muscle is fixed
The force of the contraction and the force of the resistance
The simultaneous actions of other muscles that are associated with the same structure

Question 8

Agonist

Answer 8

mover; muscle is a mover when its contraction results in the desired movement of the joint

Question 9

prime movers

Answer 9

muscle whose primary function is to cause a particular movement; strong contributor

Question 10

assistant movers

Answer 10

ability to assist in the movement is secondary in the movement

Question 11

antagonist

Answer 11

opposes the movement of an agonist

Question 12

stabilizer

Answer 12

fixator; muscles that stabilize the segment on which another segment moves
usually contracts isometrically

Question 13

neutralizer (synergistic)

Answer 13

muscles nullify one or more actions of another muscle

Question 14

prime neutralizer

Answer 14

will cause the opposite motion of the prime mover without assisting it in movement

Question 15

multi-joint muscle

Answer 15

extends across more than one point and potentially can contribute to the movement at each joint

Question 16

In regards to the bicep, the tricep would be referred to what?

Answer 16

An antagonist; directly opposes the agonist

Question 17

Insufficiency

Answer 17

inability of multijoint muscle to contract maximally over all joints crossed simultaneously

Question 18

active insufficiency

Answer 18

agonist; diminished ability to produce or maintain active tension; muscle is elongated to a point where there is no overlap between myofilaments; muscle is shortened when all cross-bridges have been formed

Question 19

passive insufficiency

Answer 19

antagonist; insufficient length to allow a force to complete the full range of motion available; multi joint muscles

Question 20

flexors

Answer 20

pass anterior to the axis of a joint; stabilizes the base of the agonist; can shorten to about 1/2 of the total length

Question 21

extensors

Answer 21

pass posterior to the axis of a joint

Question 22

abductors

Answer 22

pass lateral to the joint

Question 23

How are muscle tissues classified?

Answer 23

Appearance
Arrangement of the nuclei
Function

Question 24

What are the 3 types of muscle

Answer 24

cardiac
smooth
skeletal (striated)

Question 25

What are the characteristics of skeletal muscle

Answer 25

``` Striated peripheral nuclei multinucleated voluntary control action potential ```

Question 26

Describe the muscular origin

Answer 26

Usually proximal and may be fixed with movement

Question 27

Describe the muscular insertion

Answer 27

distal, more moveable

Question 28

What are the characteristics of tendons

Answer 28

``` attach bone and muscle dense collagenous activity peritendineum bundles of collagen fibers poor vascularization ```

Question 29

What are aponeuroses

Answer 29

flat, fan shaped tendons; give rise to other tendons

Question 30

Name the hierarchical structure of a muscle from smallest to largest

Answer 30

``` myofilament myofibril myofiber fascicle muscle ```

Question 31

Describe a myofilament

Answer 31

myosin- thick actin- thin organized into sarcomeres

Question 32

What is a myofibril

Answer 32

chain of sarcomeres

Question 33

What is a myofiber

Answer 33

a bundle of myofibrils muscle cell formed by myoblasts

Question 34

What is a fascicle

Answer 34

bundle of myofibers

Question 35

What are the 3 connective tissue supports of a muscle?

Answer 35

Endomysium Perimysium Epimysium

Question 36

What is the endomysium

Answer 36

surrounds each muscle fiber, lies outside of the sarcolemma

Question 37

What is the perimysium

Answer 37

surrounds each fascicle

Question 38

What is the epimysium

Answer 38

surrounds each muscle cutaneous with tendons attached to the periosteum

Question 39

Describe actin

Answer 39

portion of the myofilament each filament (F actin) is made by 2 monomers of G actin tropomyosin and troponin

Question 40

Describe myosin

Answer 40

Bundles of long molecules attach to binding sites on actin filaments swivel release cycles allow actin and myosin to slide against each other

Question 41

Describe the structure of a sarcomere

Answer 41

-Z lines are on the ends -I bands are next (actin) -A bands are in the middle and composed of actin and myosin -H band- myosin -Sarcoplasmic reticulum -T tubules -Cisternae

Question 42

True or false: The number of myofibers can be increased after birth

Answer 42

False

Question 43

What will muscle tissue be replaced with if it is lost

Answer 43

scar tissue

Question 44

What is the sarcoplasmic reticulum

Answer 44

equivalent to the ER of cells

Question 45

What is the function of the T tubules

Answer 45

tubular extensions of the muscle fiber that goes into the cytoplasms and conducts action potential

Question 46

What is the function of the cisternae

Answer 46

They are secular extension od the Sarcoplasmic retculum that release calcium ions to elicit a muscle contraction

Question 47

What happens to the sarcomere as the muscle contracts

Answer 47

The I and the H bands shorten | A band is the same length

Question 48

Describe the action potential sequence from the motor neuron to the contraction

Answer 48

1. the action potential arrives at the sarcolemma 2. synaptic plate intervention point 3. action potential conducted into the interior of the myofiber via T tubules 4. Action potential carried via t tubules to release Ca2+ from the cisternae 5. calcium initiates actin and myosin and the sliding motion of the myosin filaments to contract the muscle

Question 49

What is a motor unit

Answer 49

motor neuron and the myofibers that it innervates | ALL OR NONE

Question 50

Describe the dark myofibers

Answer 50

``` Slow fibers fatigue resistant contract slowly (slow twitch) lots of mitochondria- red high concentration of myoglobin low concentration of ATPase ```

Question 51

Describe the light myofibers

Answer 51

``` Fatigue easily contract quickly (fast twitch) rely on glycolysis small number f mitochondria low concentration of myoglobin high concentration of ATPase ```