Muscle Tissue

Question 1

What are muscles specialised for?

Answer 1

contraction

Question 2

What are the types of muscle tissue and what is their role?

Answer 2

skeletal - movement of body
cardiac - movement of blood
smooth - movement of gases, fluids and solid through visceral organs

Question 3

How is skeletal muscle classified?

Answer 3

somatic (voluntary) & striated

Question 4

How is cardiac muscle classified?

Answer 4

autonomic (involuntary) & striated

Question 5

How is smooth muscle classified?

Answer 5

autonomic (involuntary) & non striated

Question 6

What is a striated appearance?

Answer 6

banded

Question 7

What is the name of the outer connective tissue that encases entire muscles?

Answer 7

epimysium

Question 8

What is the name given to the connective tissue layer that surrounds bundles of muscle fibres, known as fascicles?

Answer 8

perimysium

Question 9

What is the name given to the connective tissue layer that surrounds individual skeletal muscle fibres?

Answer 9

endomysium

Question 10

What name is given to the structure formed by the coming together of the 3 connective tissue layers in skeletal muscle, at the tapering ends?

Answer 10

tendon

Question 11

What is each skeletal cell packed full of?

Answer 11

myofibrils which create the striated appearance

Question 12

What are myofibrils made from?

Answer 12

repeating proteins units called myofilaments made from actin and myosin

Question 13

What are the dark bands in electron-microscopy?

Answer 13

myosin

Question 14

What are the light bands in electron-microscopy?

Answer 14

actin

Question 15

What are the contractual units called?

Answer 15

sarcomeres

Question 16

How do they contractual units contract?

Answer 16

actin and myosin slide over each other, overlapping due to a conformational change in the sarcomere

Question 17

Describe which organelles are specialized for skeletal muscle

Answer 17

plasma membrane called sacrolemma
cytoplasm called the sacroplasm
sarcoplasmic reticulum
multinucleated

Question 18

What a motor unit?

Answer 18

A single motor neurone together with all the muscle fibres it innervates

Question 19

What is the process of muscle contraction called?

Answer 19

Excitation-Contraction coupling

Question 20

What is the chemical messenger converted from neuronal action potential that simulates the action potential in skeletal muscle cells?

Answer 20

acetylcholine

Question 21

What structural feature of skeletal muscle fibres propagates action potentials into the interior of the cell?

Answer 21

T tubules

Question 22

What happens at the action potential?

Answer 22

When the muscle is stimulated, calcium ions are released from its store inside the sarcoplasmic reticulum, into the sarcoplasm (muscle )

Question 23

What structural feature of skeletal muscle fibres sequesters calcium away from myofibrils during relaxation?

Answer 23

sarcoplasmic reticulum

Question 24

What is the function of cardiac muscle?

Answer 24

Specialized for continuous autonomous contractions
Pump blood through the cardiovascular system

Question 25

What is the structure of cardiac muscle?

Answer 25

elongated, branched cylindrical cells 1 or 2 centrally located nuclei similar arrangement of contractile proteins as in skeletal muscle causing striated appearance

Question 26

What are the layers of cardiac muscle?

Answer 26

Pericardium (P): Outer supporting tissue layer Myocardium (M): Cardiac muscle tissue Endocardium (E): Single layer of endothelial cells

Question 27

What do the intercalated discs at the end of cardiomyocytes contain?

Answer 27

desmosomes, gap junction

Question 28

What are the cells of cardiac muscle?

Answer 28

cardiomyocytes

Question 29

What are the similarities between cardiac and skeletal muscle?

Answer 29

identical arrangement of sacromeres both have t tubules and sarcoplasmic reticulum contraction happens by sliding -filament mechanism

Question 30

What are the differences between cardiac and skeletal muscle?

Answer 30

In cardiac muscle cells the SR slowly leaks Ca so that the heart can generate its own action potential instead of only releasing at an action potential no motor neuron needed in cardiac muscles as single travels through gap junctions at the end of intercalated discs

Question 31

All cells in cardiac muscle work as a single unit, what is this called?

Answer 31

syncytium

Question 32

What is a 'conducting system'?

Answer 32

The conducting system is a group of cells that can initiate the contractions without any outside stimulus

Question 33

What can undergo spontaneous depolarisation?

Answer 33

pacemaker cells

Question 34

Describe the conducting system of cardiac muscle

Answer 34

Signal to contract will travel from sinotrial node (pacemaker cells) to atrioventricular node – this movement will trigger the atria to contract and push blood from atria to the ventricles. - from the node the signal to contract will travel to the bundle of his to the purkinje fibres where they reveal that signal to the cardiac muscle cells

Question 35

Where is smooth muscle found?

Answer 35

lining hollow organs

Question 36

What is the structure of smooth muscle?

Answer 36

Elongated, spindle-shaped cells with tapered ends Single centrally located nuclei No sarcomeres hence no striations

Question 37

What is peristalsis?

Answer 37

Peristalsis is a wave of contraction in the gastrointestinal tract followed by relaxation

Question 38

What only exists in smooth muscle?

Answer 38

desmin

Question 39

What does the smooth muscle look like contracted?

Answer 39

globalar

Question 40

What does the smooth muscle look like relaxed?

Answer 40

elongated

Question 41

What does the smooth muscle not have?

Answer 41

no myofibrils or sarcomeres

Question 42

What is the adventitia referred to in the abdominal cavity?

Answer 42

serosa

Question 43

What name is given to the innermost layer (luminal surface) that is composed predominantly of epithelium in the intestine?

Answer 43

mucosa

Question 44

Name the section directly beneath the mucosa

Answer 44

submucosa

Question 45

Name the section directly beneath the submucosa

Answer 45

muscularis propria

Question 46

Name the section directly beneath the muscularis propria

Answer 46

serosa

Question 47

What are mucus-secreting cells called?

Answer 47

goblet cells

Question 48

How many nuclei does smooth muscle have?

Answer 48

one

Question 49

What is the position of the nuclei in cardiac muscle cells?

Answer 49

Central

Question 50

What is the zigzag portion called that forms the boundary ends of each sarcomere?

Answer 50

z line

Question 51

What are the thick filaments in sarcomeres?

Answer 51

myosin

Question 52

What are the thin filaments in sarcomeres?

Answer 52

actin

Question 53

What do T tubules do?

Answer 53

they also transmission of the action potential across the sarcoplasm

Question 54

Where is calcium concentrated?

Answer 54

sarcoplasmic reticulum

Question 55

What is the M line?

Answer 55

the middle of the sarcomere

Question 56

What is the I line?

Answer 56

where actin filaments are (no overlapping)

Question 57

Why are intercalated discs present in cardiac muscle?

Answer 57

for rapid transmission of stimuli between cells and points of anchoring

Question 58

How are actin and myosin arranged in smooth muscle?

Answer 58

criss-cross lattice

Question 59

In smooth muscle, calcium binds to what molecule to create contraction?

Answer 59

calmodulin

Question 60

What is the band that contains only myosin filaments?

Answer 60

H band

Question 61

What is the band where myosin and actin filaments overlap?

Answer 61

A band