Muscle Histology

Question 1

A muscle _______is a cell, while muscle ________ and muscle ________ are structures within the cell.

Answer 1

Fiber
Fibril
Filament

Question 2

What are the histology names for muscle fibers, fibrils, and filaments?

Answer 2

Myofiber
Myofibril
Myofilament

Question 3

Muscle forms the flesh of the body, and over __% of body weight

Answer 3

40%

Question 4

Muscle is specialized for ________.

Answer 4

Contraction

Question 5

Muscles transform _____ into mechanical _______.

Answer 5

ATP

Energy

Question 6

What are the 4 functions of skeletal muscle?

Answer 6

Create movement
Stabilize joints
Maintain posture
Create heat

Question 7

In embryo, ________ elongate and fuse together

Answer 7

myoblasts

Question 8

Nuclei in muscle cells are pushed to the side by many ________ proteins.

Answer 8

Contractile proteins

Question 9

Postnatally, muscles increase in ________, not _______.

Answer 9

Size

Number

Question 10

What is the plasma membrane of muscle cell?

Answer 10

Sarcolemma

Question 11

What is the cytoplasm of a muscle cell?

Answer 11

Sarcoplasm

Question 12

What two things of note are in sarcoplasm?

Answer 12

Glycogen

Myoglobin

Question 13

What is myoglobin?

Answer 13

A red pigment that binds O2 until its needed

Question 14

What CT surrounds a myofiber?

Answer 14

Endomysium

Question 15

What CT surrounds a fascicle of fibers?

Answer 15

Perimysyium

Question 16

What CT surrounds the whole muscle?

Answer 16

Epimysium

Question 17

How is tendon formed?

Answer 17

All three of these CTs meet at the ends of muscles to form the tendon

Question 18

What does a tendon do? What shape is it?

Answer 18

Connects muscle to bone, is round in shape

Question 19

What is aponeurosis?

Answer 19

A sheet of CT (dense regular) connecting a muscle to the part it moves

Question 20

What is an example of aponeurosis?

Answer 20

Found on the skull and in the abdomen

Question 21

What color are the markings on skeletal muscle?

Answer 21

Skeletal muscle has alternating dark and light bands

This are not surface markings, involve total fiber thickness

Question 22

What is a myofibril?

Answer 22

Inside the cell, are long, rod-like contractile elements, most of cell volume

Question 23

What are myofibrils made of?

Answer 23

Myofilaments

Question 24

What two components make myofibrils?

Answer 24

Actin: A thinner filament of protein
Myosin: A thicker filament of protein

Question 25

What is the A band?

Answer 25

The dark overlap of actin and myosin

Question 26

What is the I band?

Answer 26

The light band, only actin is present

Question 27

In 3-D, 6 ______ surround 1 ______.

Answer 27

Actin | Myosin

Question 28

What is the functional unit of skeletal muscle?

Answer 28

The sarcomere

Question 29

What is the smallest contractile unit of the muscle?

Answer 29

The sarcomere

Question 30

What are the Z lines?

Answer 30

They define the sarcomere; are a disc that anchors the myofilaments

Question 31

What is the H zone?

Answer 31

In the middle of the sarcomere, only visible in relaxed muscle

Question 32

What is the M line?

Answer 32

Fine stabilizing threads that interconnect the myosin filaments

Question 33

Which muscle zone can only be seen when the muscle is at rest?

Answer 33

The H zone

Question 34

What is the sarcoplasmic reticulum?

Answer 34

Interconnecting tubules that surround each myofibril, like the sleeve of a sweater

Question 35

In the sarcoplasmic reticulum, which way do most tubules run?

Answer 35

Longitudinally

Question 36

What is the terminal cisternae? Where is it found?

Answer 36

Perpendicular channels formed at the A-I band junction

Question 37

What is a T tubule?

Answer 37

A tube that travels through the muscle fiber and out the other side This elongated tubule is called the T (transverse) tubule, and contains ECF

Question 38

Where is the T tubule located?

Answer 38

At the A-I band junction

Question 39

The T tubule is an __________ of sarcolemma into the cell interior.

Answer 39

Invagination

Question 40

How does the T tubule assist with signal transmission?

Answer 40

This tremendously increases the muscle fiber’s surface area When the sarcolemma is depolarized, the signal goes along the surface and down into the interior through the T tubule- and is very efficient

Question 41

The T Tubules encircle each _______, and pass from one myofibril to the next

Answer 41

myofibril

Question 42

What fluid do T tubules contain?

Answer 42

ECF

Question 43

What is the triad?

Answer 43

Each T tubule is between 2 terminal cisternae

Question 44

The signal to contract will go down the T tubule and release stored ______ out into the sarcoplasm

Answer 44

Ca++