BMS10-1018 Muscle Histology

Question 1

Which non-muscle cells make up muscle tissue?

Answer 1

Fibroblasts

Exocrine epithelial

Question 2

What do myoepithelial muscle cells do?

Answer 2

Secrete milk

Question 3

What are the precursors?

Answer 3

Myoblasts

Question 4

What do dorsal medial cells form, with an example?

Answer 4

Myotome muscles e.g. deep back muscles

Question 5

What do ventral lateral lip cells form with an example?

Answer 5

Hypaxial myotome e.g. body wall muscles

Question 6

Where do these 2 types of cells originate?

Answer 6

Lips of the dermomyotome

Question 7

What forms myosin?

Answer 7

Myoblast fusion

Question 8

When and what does the endo, peri and epimysium fuse?

Answer 8

With dense collagenous connective tissue of the tendon at the myotendinous junction

Question 9

What does the endomysium of skeletal muscles contain?

Answer 9

Blood vessels

Fibroblasts

Question 10

What are myofibres?

Answer 10

Skeletal muscle fibres

Question 11

Sarcomere

Answer 11

Contractile unit of skeletal muscle

Question 12

Striations

Answer 12

Alternating light and dark bands appearing across the length of the fibre

Question 13

What makes up thick filaments?

Answer 13

Myosin

Question 14

M line

Answer 14

Down the middle of the myofibril due to creatine kinase

Question 15

H zone

Answer 15

Myosin

Question 16

A band

Answer 16

Overlap of actin and myosin

Question 17

I band

Answer 17

Actin

Question 18

Z line

Answer 18

Border of the sarcomere

Question 19

Costameres

Answer 19

Regions associated with the sarcolemma of skeletal muscles that transfer the force from the sarcomere to the extracellular matrix at the Z line so its transferred to neighbouring sarcomeres

Question 20

What innervates a myofibre?

Answer 20

One motorneuron

Question 21

NMJ

Answer 21

Where nerves form synapses on the muscle fibre membrane

Question 22

How many muscle fibres does a motorneuron have contact with and what is this called?

Answer 22

Many, a motor unit

Question 23

What does a large muscle unit indicate?

Answer 23

Don’t need a fine degree of control

Question 24

How many NMJ does a muscle fibre have?

Answer 24

Normally 1

Question 25

Motor unit

Answer 25

Muscle fibres innervated by the same motor neuron

Question 26

Where is fast myosin found?

Answer 26

White muscle fibres

Question 27

Why do fast fibres quickly fatigue?

Answer 27

Have little myoglobin (oxygen binding protein)

Question 28

Where are slow fibres found?

Answer 28

Red muscle fibres

Question 29

Which 2 parts of the body don't have a mix of both fast and slow fibres?

Answer 29

Posture muscles are all slow | Eye muscles are all fast

Question 30

Where are triads?

Answer 30

Pair at the A I border

Question 31

T tubules

Answer 31

Allows for propagation of the action potential

Question 32

What is a triad?

Answer 32

T tubules with the sarcoplasmic reticulum

Question 33

Terminal cisternae

Answer 33

Enlarged areas of the sarcoplasmic reticulum around T tubules for Ca release

Question 34

Muscle fibres are specialised...

Answer 34

Post-mitotic cells

Question 35

Can nuclei of fibres re enter the cell cycle?

Answer 35

No so they cant divide

Question 36

What is on the surface of muscle fibres?

Answer 36

Satellite cells

Question 37

Are satellite cells always active?

Answer 37

No mainly they aren't dividing but they can be activated to enter the cell cycle to become myoblasts

Question 38

What do myoblasts become?

Answer 38

Fuse to make new myofibres | Specialise to provide myonuclei for existing fibres

Question 39

What do satellite cells sits on?

Answer 39

Basal lamina

Question 40

Where are the nuclei in cardiac cells?

Answer 40

Centrally

Question 41

How do cells connect and what do they form?

Answer 41

Intercalated discs to form a functional syncytium

Question 42

What are intercalated disks?

Answer 42

Modified Z lines

Question 43

What allows for transmission of action potentials?

Answer 43

Gap junctions

Question 44

Why cant we regenerate cardiac muscle?

Answer 44

No satellite cells

Question 45

What does actin connect to either side of the gap junction?

Answer 45

Desmosome | Fascia adherens

Question 46

What NS modulate HR?

Answer 46

Para and sym

Question 47

Why doesn't the heart rely on neurons?

Answer 47

Uses the muscle cells and purkinje fibres

Question 48

What are purkinje fibres?

Answer 48

Conductive myocytes

Question 49

Where is smooth muscle found?

Answer 49

Walls of vessels, respiratory tract, gut and urinary tract

Question 50

What surrounds smooth muscle?

Answer 50

Basal lamina and connective tissue

Question 51

What are smooth muscles filled with?

Answer 51

Actin and not a lot of myosin

Question 52

How does electrical excitation spread?

Answer 52

Gap junctions

Question 53

Why aren't smooth muscles striated?

Answer 53

Different composition of actin and myosin

Question 54

What controls contraction?

Answer 54

Hormones | Sym VS Para