Week 3

Question 1

What is the origin

Answer 1

The fixed point of attachment

Question 2

Whats the insertion

Answer 2

Moveable point of attachment,usually distal to the origin

Question 3

Whats a flexor

Answer 3

Muscles whose lines of action cross the anterior side of a joint
Eg.biceps brachili, triceps brachili

Question 4

Whats an extensor

Answer 4

Muscles who’s lines of action cross the posterior side of a joint

Question 5

What is a lever

Answer 5

A lever is a rigid structure of the moves on a fixed point called a fulcrum

Question 6

What does an applied force result in

Answer 6

It results in an exerted force

Question 7

What do lever systems change

Answer 7

The direction of an applied force
The distance and speed of movement produced bu the applied force
The magnitude of the exerted force relative to the applied force

Question 8

Parallel muscles

Answer 8

The muscle fibre bundles are parallel to the long axis of the muscle
-attach to skeleton with little or no tendon
Eg sartorius muscle

Question 9

Pennate muscles

Answer 9

The muscle fibre bundles are shorter than the muscle and run at an angle to the principal axis of the muscle
-attach to skeleton via and external tendon
Eg rectus femoris muscle (bipennate)

Question 10

Function consequences of gross muscle architecture

Answer 10

Pennate muscles have a cross sectional area that is higher than thay of the parallel fibred muscle so has more force

Paralled fibred muscles can undergo longer length chanhes and can shorten more quickly

Question 11

Whats fascicles

Answer 11

The muscles fibre bundles

Question 12

Circular muscles

Answer 12

The muscle fibre bundles are concentrically arranged around an opening
They control the diameter od body openings or hollow organs

Question 13

Moment equation

Answer 13

Moment=force x distance

Question 14

Work equation

Answer 14

Work=force x distance

Question 15

Power equation

Answer 15

Work/time

Question 16

Muscle actively shorten=_________

Answer 16

Concentric contraction

Question 17

Muscles as motors generate_____

Answer 17

Positive work and positive power

Question 18

Muscles as brakes absorb_______

Answer 18

Absorb energy and generate negative power

Question 19

Muscle actively lengthens=

Answer 19

Eccentric contraction

When muscles are brakes

Question 20

Muscles as struts generate______

Answer 20

Force wirhout shortening (isometric contraction)

Question 21

What is the heirarchal organisation in skeletal muscles

Answer 21

Whole muscle (connective tissue)
Muscle fibres
Myofibrils
Sarcomeres

Question 22

Describe muscle fibres

Answer 22

10-100um
Often run full length
Bundles (fascicles)

Question 23

Describe myofibrils

Answer 23

1-3um arranged in groups

Made up of sarcomeres

Question 24

Describe sarcomeres

Answer 24

Muscle proteins (myosin and actin) assemble in to thick and thin filaments
Seperated by z disks
2:1 ratio of thick and thin filaments

Question 25

What are the 3 layers of connective tissue:

Answer 25

Epimysium-covers the outside muscle Perimysium-covers the fascocles Endomysium-surrounds individual fibres

Question 26

Thick filaments

Answer 26

Held in position by titin | Made up of myosin but different cross bridge cycling rates

Question 27

Myosin

Answer 27

Has two heads (motor) (16nm) And a tail (155nm)

Question 28

Thin filaments

Answer 28

- Made up of actin - G actin is a globular protein;polymerises in to double stranded helix filamentous, F actin - z disk contains alpha acitinin which anchors the tjin filaments - nebulin holds the thin filament together - thin filaments also contain the proteins tropomyosin and tropomin

Question 29

Tropomyosin

Answer 29

Lies in the grooves of F actin

Question 30

Sarcoplasmic reticulum

Answer 30

Forms a network of vesicular elements that surround the myofibrils Calcium ions to calsequestrin in the terminal cisternae in relaxed muscle When free calcium ions diffuses to the myofibrils and binds with Tn-C Tm-C undergoes conformational change allowing cross bridges to form

Question 31

What does activation mean?

Answer 31

Increase in calcium ions Binding of Calcium ioma to troponin Binding of cross bridges to actin and development of force

Question 32

What does deactivation mean?

Answer 32

Decrease in calcium ions Release of calcium ions from troponin Release of crossbridges actin and decrease in force (relaxation)

Question 33

Sliding filament hypothesis

Answer 33

Filaments Dont change length During contraction a band stays the same but z lines moce closer and i band fet smaller Sarcomeres shorten ans myofibrils pulled toward its centre

Question 34

Isometric twitches

Answer 34

Produced in repsonse to a single stimulus

Question 35

Delay between stimulus and rise in force=

Answer 35

Latency period

Question 36

The infraspinatus has its insertion on the: - greater tubercle of the humerus. - tuberosity of the radius. - lesser tubercle and intertubercular groove of the humerus. - clavicle and scapula. - vertebral border near the spine.

Answer 36

-greater tubercle of the humerus.

Question 37

Which of the following does not originate on the humerus? - anconeus - brachialis - brachioradialis - biceps brachii - anconeus and brachioradialis

Answer 37

biceps brachii

Question 38

Individuals who are engaged in repetitive hand movements such as typing or playing the piano may suffer wrist pain, especially during palmar flexion. All of the following are true concerning this condition except that it: - is called carpal tunnel syndrome. - results from inflammation of the synovial tendon sheaths. - never causes muscle weakness. - results from inflammation of the carpal retinacula. - irritates the median nerve.

Answer 38

-never causes muscle weakness.

Question 39

Which of the following controls adduction at the shoulder? - supraspinatus - subscapularis - teres major - infraspinatus - teres minor

Answer 39

-teres major

Question 40

In a ________ muscle, the fascicles are concentrically arranged around an opening. - convergent - parallel - straight - pennate - circular

Answer 40

-circular

Question 41

A muscle that assists another by preventing movement at another joint is called a(n) - synergist. - fixator. - agonist. - prime mover. - antagonist.

Answer 41

-fixator

Question 42

Nerves and blood vessels that service a muscle fiber are located in the connective tissues of its - endomysium. - perimysium. - sarcolemma. - sarcomere. - myofibrils

Answer 42

-endomysium.

Question 43

Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass? - epinephrine - thyroid hormone - testosterone - parathyroid hormone - calcitonin

Answer 43

-testosterone

Question 44

``` The region of the sarcomere containing the thick filaments is the Z line. M line. H band. A band. I band. ```

Answer 44

A band

Question 45

When acetylcholine binds to receptors at the motor end plate, the sarcolemma becomes - more permeable to sodium ions. - less permeable to sodium ions. - more permeable to calcium ions. - less permeable to potassium ions. - less permeable to potassium and sodium ions

Answer 45

-more permeable to sodium ions.

Question 46

The sequence of processes that links the action potential to contraction is called - neuromuscular junction. - action potential propagation. - excitation-contraction coupling. - cross bridge formation. - sliding filament theory.

Answer 46

-excitation-contraction coupling.

Question 47

he action potential is conducted into a skeletal muscle fiber by: - motor end plates. - neuromuscular junctions. - transverse tubules. - triads. - sarcoplasmic reticulum.

Answer 47

-transverse tubules.

Question 48

Which skeletal muscle fiber type?slow or fast?contains more mitochondria? - slow - fast

Answer 48

slow

Question 49

The type of contraction where the tension exceeds the load is called: - isometric contraction. - isotonic eccentric contraction. - isotonic concentric contraction. - isometric concentric contraction. - isometric eccentric contraction.

Answer 49

-isotonic concentric contraction.

Question 50

A muscle that dorsiflexes the foot is the: - tibialis anterior. - tibialis posterior. - peroneus brevis. - soleus. - gastrocnemius.

Answer 50

-tibialis anterior.

Question 51

Muscles of the rotator cuff include all of the following except the - supraspinatus. - infraspinatus. - subscapularis. - teres minor. - rhomboid.

Answer 51

-rhomboid.

Question 52

The only knee flexor that originates superior to the acetabulum is the - biceps femoris. - gracilis. - sartorius. - iliopsoas. - semimembranosus.

Answer 52

-sartorius.

Question 53

Which quadriceps femoris muscle is not visible from the superficial anterior thigh? (Figure - vastus lateralis - vastus medialis - vastus intermedius - rectus femoris - biceps femoris

Answer 53

-vastus intermedius

Question 54

The ability of smooth muscle to function over a wide range of lengths is called - elasticity. - contractility. - extensibility. - plasticity. - variability.

Answer 54

-plasticity

Question 55

Which of the following is not characteristic of smooth muscle? - The striations are due to the orderly arrangement of actin and myosin. - Neurons that innervate smooth muscles are under involuntary control. - Smooth muscle cells are uninucleate. - Smooth muscles do not contain sarcomeres. - The thin filaments of smooth muscle fibers are attached to dense bodies.

Answer 55

-The striations are due to the orderly arrangement of actin and myosin.