BL- Muscle Tissue strcuture, function and dysfunction

Question 1

What is myasthenia

Answer 1

Weaknes of muscles

Question 2

What is the myocardium

Answer 2

Muscular component of the heart

Question 3

What is myopathy

Answer 3

Any diseases of the muscles

Question 4

What is myoclonus

Answer 4

A sudden spasm of the muscles

Question 5

Skeletal muscle

Answer 5

Myoglobin present

Voluntary control

Striated

Direct nerve to nurse communication

Question 6

Cardiac muscle

Answer 6

Myoglobin present

Striated

Involuntary control

Indirect nerve-muscle communication

Question 7

Smooth muscle

Answer 7

No myoglobin
Involuntary control
No direct nerve-muscle communication

Question 8

What is myoglobin?

Answer 8

A red protein similar in structure to haemoglobin
It provides oxygen to working striated muscle

Haemoglobin gives up oxygen to myoglobin at low pH

Question 9

What does myoglobin in the blood indicate

Answer 9

That striated muscle has died-muscle necrosis

This is because myoglobin is released into the bloodstream and into the urine

Can causerenal damage

Question 10

What is the sarcolemma 
Sarcplamsm
Sarcosome 
Sarcomere 
Sarcoplasmic reticulum

Answer 10

• outer membrane of muscle cells
• cytoplasm of a muscle cell
• Mitochondrion
• contraction unit in striated muscle
• smooth endoplasmic reticulum of a muscle cell

Question 11

What causes movement in skeletal muscle

Answer 11

When the point of origin and the point of insertion of a muscle cross a joint

Movement is dependant on direction of muscle fibre

Tension is created at the origin tendon point
Movement is created at the insertion tendon point

Question 12

What is a myofibroblasts

Answer 12

Contractile unit that sits within the single cell

Question 13

Where are the nuclei in skeletal muscle

Answer 13

Peripheral

Question 14

What are the here types of muscle contraction speeds

Answer 14

Slow fast intermediate

Each fasciae has at lease one of each

Intermediate sometimes classed as fast twitch

Question 15

What causes the red colour in sow twitch fibres

Answer 15

Myoglobin and cytochrome

Question 16

What colour are fast twitch fibres

Answer 16

White

Question 17

What is endomysium
Perimysium
Epimysium

Answer 17

Group myofibrils
Group fascicles
Group muscles

Question 18

Where is the nucleus positioned in cardiac cells

Answer 18

In the centre

Question 19

What is hypertrophic

Answer 19

Enlargement of their individual cells

Question 20

What is hyperplasia

Answer 20

Multiplication of their cells

Question 21

What is atrophy/ hypertrophy

Answer 21

Cells gets smaller/bigger

Question 22

What is the sarcomere like in cardiac cells and what is the contractile unit called

Answer 22

Not so developed

Only one type- cardiomyocyte

Question 23

How do cardiomyocyes communicate

Answer 23

Gap junctions.

Question 24

Structure of smooth muscle cels

Answer 24

Single central large nucleus

Not striated

No sarcomere

No T tubules

Question 25

Contraction of smooth muscle cells

Answer 25

Slower and more sustained and require less ATP

Can remain contracted for hours or days

Question 26

Can skeletal muscle be repaired

Answer 26

Cant divide but can be regenerated by mitosis activity of satellite cells so that hyperplasia follows muscle injury

Question 27

Can adult cardiac muscle regenerate

Answer 27

No following damage fibroblast invade, divide and lay down scar tissue

Question 28

Can smooth muscle be regenerated

Answer 28

They can retain their mitotic activity and can form new smooth muscle cells
Evident in pregnant uterus where muscle wall becomes thicker by hypertrophy

Question 29

What do cardiac and smooth muscle have in common

Answer 29

Nuclei are central not peripheral
Only one contractile unit
Act as syncytium- wave-like function
Myocytes communicate through gap junctions

Question 30

What are the differences in cardiac and smooth muscle

Answer 30

Smooth muscle does not contain sarcomeres
Electrical conduction - specialised cells/ routes in cardiac muscle
No troponins in smooth muscle

Question 31

What is myasthenia gravis

Answer 31

Autoimmune disease

Antibodies block ACh receptor

Endplate ‘invaginations’ in synaptic clefts reduced

Reduced synaptic transmission

Intermittent muscle weakness

Question 32

What is the structure of myosin

Answer 32

Rod like structure with 2 heads protruding

Question 33

What does the thick filament consist of

Answer 33

Many myosin molecules

Question 34

What is the protein components of actin

Answer 34

F-actin fibres

G-actin globules

Question 35

What forms the thin filaments of skeletal and cardiac muscle

Answer 35

Actin
Tropomyosin
Troponin

Question 36

What is the role of calcium in contraction

Answer 36

As Ca2+ binds to TnC to tropinin a conformational change moves tropomyosin away from actins binding sites

This allows myosin to bind actin and contraction begins

The tropomyosin sits in the cleft of G-actin spheres

Question 37

What remains the same during contraction, shorten and com closer

Answer 37

Actin and myosin lengths
Filaments

Sarcomere

Z line

Question 38

What is the point of origin and insertion for muscles

Answer 38

Bone- typically proximal

The structure the muscle attaches to- distal- may be bone, connective tissue, or tendon (mostly tendon)

Question 39

What are agonists

Answer 39

Prime movers- main muscles responsible for a particular movement

Question 40

What are antagonists

Answer 40

Oppose prime moves

Question 41

What are synergists

Answer 41

Assist prime movers

Question 42

What are neutralisers and fixations

Answer 42

Neutralisers- prevent the unwanted actions that an agonist can perform

Fixators- act to hold a body part immobile whilst another body part is moving

Question 43

What is myalgia

Answer 43

Muscle pain