Exam 2 – Lecture 11: Muscle

Question 1

What is the only thing muscles can do actively?

Answer 1

Get shorter

Question 2

What are the names of muscles based on?

Answer 2

Morphology and activity

Question 3

What is a muscle?

Answer 3

A tissue type

A specific mass of muscle tissue with origin, insertion, and action

Question 4

What is a myofiber?

Answer 4

Individual muscle cell

Question 5

What is a myofibril?

Answer 5

Contractile elements within a myofiber

Bundles of myofilaments

Question 6

What can the shape of a muscle be like?

Answer 6

Flattened or cylindrical

Question 7

What does the arrangement of myofibers determine?

Answer 7

Mobility/dexterity

Question 8

What are the layers of a muscle fiber?

Answer 8

Epimysium
Perimysium
Endomysium

Question 9

What is epimysium?

Answer 9

Connective tissue that surrounds the muscle

Question 10

What is perimysium?

Answer 10

Connective tissue around a bundle (muscle fascicle)

Question 11

What is a muscle fascicle made of?

Answer 11

Many myofibers

Question 12

What is endomysium?

Answer 12

Connective tissue that surrounds each individual myofiber

Question 13

What is a myofiber like?

Answer 13

Elongated
Frequently multinucleated
Contains filaments or fibrils

Question 14

What are the different types of filaments?

Answer 14

Actin, thin (6-8 nm)

Myosin, thick (15 nm)

Question 15

What are the different categories of morphology?

Answer 15

Smooth striated

Question 16

What are the different categories of activity?

Answer 16

Voluntary

Involuntary

Question 17

Describe skeletal muscle

Answer 17

Voluntary, striated

Multinucleated

Question 18

What does skeletal muscle act as?

Answer 18

Syncytium

Question 19

Where are the nuclei of skeletal muscle located?

Answer 19

In the periphery of the cell

Question 20

What are the different fiber types of skeletal muscle?

Answer 20

Types 1, IIa, and IIb

Question 21

What kind of twitch do type I fibers have?

Answer 21

Slow

Question 22

What kind of metabolism do type I fibers have?

Answer 22

Oxidative

Question 23

Do type I fibers have many or few mitochondria?

Answer 23

Many

Question 24

What do type I fibers have a large amount of?

Answer 24

Myoglobin and cytochrome

Question 25

Because type I fibers are slow twitch, what does that mean in terms of fatigue?

Answer 25

Fatigue resistant

Question 26

Where can type I fibers be found?

Answer 26

Mammal limbs, migratory bird breast, marathon runners

Question 27

What kind of twitch do type IIa fibers have?

Answer 27

Fast

Question 28

What kind of metabolism do type IIa fibers have?

Answer 28

Oxidative glycolytic

Question 29

Describe type IIa fibers

Answer 29

Many mitochondria Much myoglobin Abundant glycogen Capable of anaerobic function

Question 30

What kind of twitch do type IIb fibers have?

Answer 30

Fast

Question 31

What kind of metabolism do type IIb fibers have?

Answer 31

Glycolytic

Question 32

Describe type IIb fibers?

Answer 32

Large fibers Less myoglobin and mitochondria Much glycogen High lactic acid production

Question 33

What do myofibrils provide?

Answer 33

Striations

Question 34

What do myofibrils make up?

Answer 34

Sarcomere

Question 35

What is within the sarcomere?

Answer 35

``` A band I band M line Z line H band ```

Question 36

What is the A band composed of?

Answer 36

Mostly myosin

Question 37

What is the I band composed of?

Answer 37

Mostly actin

Question 38

Where is the M line?

Answer 38

Center of the A band

Question 39

What happens in the Z line?

Answer 39

Actin filaments conjoin between adjacent sarcomeres

Question 40

What is the H band?

Answer 40

Space between actin filaments

Question 41

Know the picture of a sarcomere

Answer 41

Know the picture of a sarcomere

Question 42

During muscle contractions, what happens to myofilaments?

Answer 42

They remain the same length

Question 43

When myofilaments remain the same length, what happens to interdigitation? H and I zones? A band?

Answer 43

Increases Get smaller Remains

Question 44

What is muscle contraction controlled by?

Answer 44

Ca++

Question 45

Where is Ca held?

Answer 45

Sarcoplasmic reticulum

Question 46

What is the T-tubular system?

Answer 46

Invaginations of plasma membrane

Question 47

What happens when the T-tubule depolarize?

Answer 47

Ca is released

Question 48

What makes up the neuromuscular junction?

Answer 48

Axon and myofiber

Question 49

What is the neurotransmitter in the neuromuscular junction?

Answer 49

Acetylcholine