Lecture 9 part one (SECOND MIDTERM)

Question 1

What kind of tissue surrounds the muscle? What is it called?

Answer 1

Connective tissue; Epimysium

Question 2

What makes up a muscle?

Answer 2

Fascicles or muscle bundles

Question 3

What kind of tissue surrounds the muscle bundle? What is it called?

Answer 3

Connective tissue; Perimysium

Question 4

What makes up the muscle bundle?

Answer 4

Muscle fibers/cells (myocytes)

Question 5

What kind of tissue surrounds the muscle cells? What is it called?

Answer 5

Connective tissue; Endomysium

Question 6

What makes up muscle fibers/cells?

Answer 6

Muscle fibrils (myofibrils)

Question 7

What makes up the muscle fibrils?

Answer 7

Sarcomeres

Question 8

What makes up a sarcomere?

Answer 8

Muscle filaments

Question 9

What makes up a muscle filament?

Answer 9

Proteins

Question 10

What is the smallest functional unit of the muscle fiber?

Answer 10

sarcomere

Question 11

The complex of a transverse tubule and two adjacent terminal cisternae is known as a…

Answer 11

triad

Question 12

Name the muscle layers from superficial to deep.

Answer 12

Epimysium
Perimysium
Fascicle
Endomysium
Muscle Fiber
Myofibril

Question 13

The repeating unit of a skeletal muscle fiber is the…

Answer 13

sarcomere

Question 14

At rest, what blocks actin from attachment to myosin?

Answer 14

troponin

Question 15

The area in the center of the A band that contains no thin filaments is the..

Answer 15

H band

Question 16

Unlike smooth and cardiac muscle, striated muscle has multiple…

Answer 16

nuclei

Question 17

2 proteins involved in skeletal (striated) muscle:

Which is thick and which is thin?

Answer 17

actin (thin) and myosin (thick)

Question 18

What makes skeletal muscle appear striated?

Answer 18

myofibrils

Question 19

What indicates the ends of the sarcomere?

Answer 19

Z lines

Question 20

What is the “middle” of the sarcomere called?

Answer 20

M line

Question 21

What do the actin attach to?

Answer 21

Z lines

Question 22

What is the portion that is JUST thin filaments?

Answer 22

I band

Question 23

What is the dark region where thin filaments are located between thick filaments?

Answer 23

Zone of overlap

Question 24

What is the plasma membrane of a muscle fiber called?

Answer 24

sarcolemma

Question 25

What does the sarcolemma surround?

Answer 25

sarcoplasm

Question 26

Each myofibril is surrounded by a network of tubes and sacs. What do the tubes and sacs do and together what are they called?

Answer 26

- They transmit the continuation of the nerve impulse to the muscle cell - Sarcoplasmic reticulum

Question 27

What runs at right angles and connects to the sarcoplasmic reticulum?

Answer 27

transverse tubules (T tubules)

Question 28

Depolarization (and action potential) from neuron at neuromuscular junction carries on through what?

Answer 28

the T-tubules

Question 29

What "stores" calcium? and where?

Answer 29

Sarcoplasmic reticulum | terminal cisternae

Question 30

Many muscle fibers may be innervated by one motor neuron. This complex is called the...

Answer 30

motor unit

Question 31

Junction between neuron and muscle fiber is the...

Answer 31

neuromuscular junction

Question 32

Actual contact, or the spot of communication, is at the...

Answer 32

motor endplate

Question 33

What floods into the end of neuron at a neuromuscular junction, triggering the release of a neurotransmitter? What is the neurotransmitter?

Answer 33

Calcium | Acetylcholine

Question 34

Sarcoplasmic reticulum releases calcium into what?

Answer 34

myofibril

Question 35

When a myosin head rocks back toward the M-line, it attaches to the actin filament and forms what?

Answer 35

a cross-bridge

Question 36

Troponin is laced around the actin in a spiral-like manner by a structural protein called what?

Answer 36

tropomyosin

Question 37

When calcium floods in, the calcium binds to what?

Answer 37

Troponin

Question 38

What does calcium do to the troponin-tropomyosin complex?

Answer 38

it changes the shape enough to move it out of the way and allow the cross-bridge to form and the myosin heads to rock backward

Question 39

What is rigor mortis?

Answer 39

When one dies, no ATP is available, and movement is not possible

Question 40

ATP is not required to... | but it IS required to...

Answer 40

rock the cross bridges | detach and reset them

Question 41

What covers the active sites on the G-actin and prevents actin-myosin interaction?

Answer 41

tropomyosin

Question 42

Thin filaments sliding toward the center of each sarcomere alongside the thick filaments is called...

Answer 42

the sliding filament theory

Question 43

Cells of cardiac muscle tissue...

Answer 43

cardiocytes

Question 44

Compared to skeletal muscle, what does cardiac muscle LACK?

Answer 44

the sarcoplasmic reticulum lacks terminal cisternae; there is NO triad!

Question 45

Skeletal muscle has long, multinucleated cells (fibers). How are cardiac cells?

Answer 45

Uninucleate and branching

Question 46

Intercalated discs are... | Function?

Answer 46

- Sarcolemmas of adjacent discs that are interdigitating and connected by gap junctions - Signal can travel directly from cell to cell, essentially causing the muscle to act like a single cell (coordinated)

Question 47

Prepotential, or pacemaker potential, is described as...

Answer 47

specialized cardiac muscle cells (more like nerves) that contain very little myofibrils are called the Conducting System or Nodal System

Question 48

Nodes included in Conducting System:

Answer 48

Sinoatrial node Atrioventricular node Conducting cells

Question 49

Even if there is no neuronal signal, what will sodium do to the heart? Because of what?

Answer 49

It will cause the membrane potential to reach threshold on its own. Because of the "leaky" cells of the nodes

Question 50

Unlike striated muscle, the calcium binds to what? What does it activate?

Answer 50

binds to Calmodulin | activates Myosin Light Chain Kinase

Question 51

What is plasticity? What muscle has this trait?

Answer 51

The ability to function over a wide range of lengths | Smooth muscle

Question 52

Kinase allows what?

Answer 52

cross bridges to form, thus initiating contraction