Muscles Flashcards

1
Q

Name the different level of muscle organisation from smallest to largest

A

myofilaments ( thick and thin protein filaments) –> myofibrils (individual fibres) —->along with Myocytes form muscle fibers)—>Muscle bundle (Fascicle)–> muscle tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name the fibrous OUTER COVERINGS of muscle levels

A

Epimysium (over entirel muscle organ)
Perimysium (around a fascicle(bundle) of muscle fibers)
Endomysium (around individual cell/fibres)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Muscles can be …… OR ……
……. OR …….

A

Voluntary OR Involuntary
Striated (multinucleated) OR non striated (mononucleated )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a striated muscle

A

MULTI nucleated muscle cells (Striped appearance)
Skeletal and cardiac muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a non-striated muscle?

A

Smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Name the types of muscles (3 main types) with an example

A

Skeletal-orbicularis iris
Cardiac-heart only
Smooth- vessel/gland linings eg ducts of glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe a skeletal muscle and 5 important features

A

most common-found all over body limbs/head etc
Striated ( multinucleated ) muscle
Voluntary control- somatic nervous system
no gap junctions
Contractile unit = sarcomere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the contractile unit of a skeletal muscle

A

sarcomere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe a cardiac muscle and 5 distinguishing features

A

Found only in the heart
- Striated muscle (multinucleated)
involuntary control
Gap junctions between sarcomeres
self excitatory (syncytium ) -ie act as 1 muscle to allow coordinated pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe a smooth muscle and 6 distinguishing features

A

Involuntary control
Non- striated
mono nucleated cells
No sarcomere structure
No t tubules
Calcium enters from OUTSIDE cell and binds CALMODULIN not troponin
2 types 1. single unit eg in gut lining
2. multi unit -eg pupil muscle

Myofilaments more free of movement (from lack of sarcomeric structure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name the 2 types of smooth muscle and differences

A

Single unit - eg lining gut
In sheets for peristalsis
self excitatory
Gap junctions - to allow impulse cell to cell

Multi unit ( pupil eye muscles)
Single units that act INDEPENDENTLY
NO Gap junctions
Not self excitatory -respond nervous stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Name and describe 3 function of skeletal muscles

A
  • Movement - by Muscle Contractions
  • Heat production -e.g. shivering)
  • Posture - continuous partial muscle contractions allow stability (e.g. standing, sitting)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the cell membrane of muscle called?

A

Sarcolemma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the cytoplasm of muscle called?

A

Sarcoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the function of the Sarcoplasmic reticulum ?

A

Store calcium ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Name the basic makeup of a skeletal muscle from start to the muscle tissue

A

Myofilaments - thin and thick protein filaments form a myofibril

1000s of myofibrils form a muscle fiber

Muscle fibers bundled to form a muscle fascicle (bundle)

Muscle bundles Form muscle tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain the basic contractile unit and its components

Think (Muscle alphabet (HIT ZAM)

A

A sarcomere is the basic contractile unit of a muscle fiber

Made up of myofilaments ( thin and thick filaments made up of 4 protein filaments
Thick filament = myosin
Thin filament - actin/troponin/tropomyosin
( troponin and tropomyosin are blocking proteins that stop when muscle relaxed the joining of the actin and myosin )

Heller (H )band - segment of the thick filament NOT overlapping the thin filament

Isotropic(I ) band - segment often filament NOT overlapping the thick filament

T tubules - infolding of the sarcolemma allowing impulse to travel - found between A and I band junction

Z disc - anchoring point t for myofilaments ( 1 sarcomere is from Z disc to next Z disc)

Anisotropic( A ) band - entire length of the thick filament

M line - middle line of thick filament ( m-orotein here anchors the thick filament )

18
Q

What 3 requirements are needed for a skeletal muscle contraction

A

Nerve impulse
Calcium flooding
ATP ( energy ) from mitochondria

19
Q

Explain how muscles are contracted.

A
  1. Nerve impulse travels down T tubule to sarcoplasmic reticulum
  2. Calcium channels open
  3. Calcium floods into the sarcolemma
  4. calcium binds to troponin unblocking the actin ACTIVE site
  5. Myosin ( thick filament ) and actin ( thin filament ) bind
  6. Actin “pulled along” past the thick filament
    .(the muscle contraction)
  7. Calcium Channels close up immediately
  8. Calcium ACTIVELY pumped back into Sarcoplasmic reticulum for storage
20
Q

What is the sliding filament theory

A

Explains the mechanism of muscle contraction , the myosin (thick filaments) of muscle fibers slide past the actin (thin filaments) during muscle contraction, while the two groups of filaments remain at relatively constant length.- if need to can explain how the muscle contracts via Calcium etc

21
Q

What is a sarcomere

A

The basic contractile unit of skeletal muscle

22
Q

What is the T tubule and where is it found

A

T ( transverse ) tubule is an inward fold of the sarcolemma of a skeletal muscle ) and allows electrical impulses to travel deep into the muscle cell.
Found between the A and I band of the sarcomere

23
Q

Name the four proteins that make up myofilaments and which filament they are found in

A
  • Myosin (thick)
  • actin (thin)
  • Troponin (thin)
  • Tropomyosin (thin)
24
Q

Name the protein filament (s ) in thick filaments

A

Myosin

25
Q

Name the protein filament in thin filaments

A

Actin
Troponin
tropomyosin

26
Q

Which are the blocking proteins in myofilaments

A

Troponin and tropomyosin ( block myosin from binding to actin)

27
Q

Are cardiac muscles non-striated / striated and voluntary / involuntary

A

striated and involuntary (smooth muscle)

28
Q

Where are cardiac muscle found?

A

Only found in heart wall

29
Q

What’s the primary function of cardiac muscles?

A

Pump blood

30
Q

How do cardiac muscles maintain a coordinated pumping action?

A

Self-exciting and act as a whole continuous electrically-coupled muscle mass thru gap junctions between sarcomeres

31
Q

In smooth muscles, calcium ions come from the outside of the cell/fibre and bind to what?

A

Calmodulin protein

32
Q

What are the 2 types of smooth muscles and an example?

A

Single unit (visceral-intestine lining)
Multi unit (pupil muscles )

33
Q

how are the smooth muscle cells/fibres connected?

A

By gap junctions

34
Q

In single unit smooth muscles, how is contraction initiated?

A

By nerve fibres and nerve impulses which pass through gap junctions from muscle to muscle

35
Q

Is the single unit smooth muscle self excitatory?

A

Yes (like cardiac muscles)
And acts as a single contractile unit

36
Q

Are multi unit smooth muscles self excitatory?

A

NO
Respond to nervous stimulation

37
Q

Describe a muscle related genetic DISORDER. (Cause and symptoms)

A

Duchenne Muscular Dystrophy (DMD)
In males only -genetic
Cause: faulty dystrophin protein- fails to anchor cytoskeleton to sarcolemma (membrane) in muscle cells

Symptom: Muscle wasting, motor skill difficulty, skeletal deformities, death in 20s
No cure

38
Q

Describe a muscle related INFECTION.

A

Tetanus (lockjaw )
Toxin produced by bacterium clostridium tetani
Overstimulates nervous system
Causes painful muscle spasms -ususally starts in the head

39
Q

What is the treatment tetanus

A

Antibiotics but there is also a vaccination of inactive toxin

40
Q
A