Muscle Tissue Flashcards

1
Q

3 types of muscle tissue

A

Skeletal cardiac and smooth

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2
Q

Classification of muscle tissue (somatic/autonomic/striations)

A

Skeletal muscle is striated and somatic
Cardiac is autonomic and striated
Smooth is autonomic and non striated

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3
Q

Common properties of all muscle tissues

A

Excitability
Contractility
Extensibility
Elasticity

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4
Q

Extensibility vs elasticity

A

Extensibility is a stretching movement of a muscle and elasticity is the ability of a muscle to recoil to its resting length

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5
Q

Ability to receive and respond to a stimulus

A

Excitability

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6
Q

Functions of skeletal muscles

A

Supporting soft tissue
Maintaining posture
Producing movement (contractions of skeletal muscles pull on tendons to move our bones )

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7
Q

Skeletal muscle are organs

A

Made of skeletal muscle tissues, connective tissue, blood vessels, nerves

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8
Q

Name the cell in skeletal muscle tissue

A

Each cell in skeletal muscle tissue is a single muscle fibre

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9
Q

Describe the structure of a skeletal muscle fibre (ie a single cell in muscle connective tissue)

A
  • elongated, cylindrical cells
  • striated
  • Multinucleated (PERIPHERALLY)
  • muscle fibres are bound together by collagenous supporting tissue (epimysium,endomysium,perimysium)
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10
Q

Tendon

A

The collagen fibres of the perimysium and endomysium are interwoven and blend into one another. At the end of the muscle, the collagen fibres of the three layers of connective tissue for, a bundle known as a tendon

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11
Q

Which two layers surround the skeletal muscle tissue contain blood vessels

A

Endo and perimysium

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12
Q

Skeletal muscle st

A
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13
Q

Perimysium CT type

A

Loose collagenous connective tissue
Has collagen and elastic fibres

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14
Q

Epimysium CT type

A

Dense collagenous connective tissue

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15
Q

Endomysium CT type

A

Delicate, loose connective tissue

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16
Q

Name of the bundle that groups muscle fibres

A

Fasciculi/ fascicles

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17
Q

Tendons vs ligaments

A

Skeletal muscles attached to bones by tendons
Ligaments hold bone to bone

18
Q

Function of Satellite cells in muscles

A

Satellite cells are stem cells that can differentiate into myoblasts to regenerate muscle

19
Q

How do the striations in skeletal muscle tissue come about

A

Due to thin actin and thick myosin filaments in the myofibrils

20
Q

What is a sarcomere

A

Thick and thin myofilaments are organised into repeating units known as sarcomeres. A myofibrils is made up of about 10000 sarcomeres

21
Q

Z line to z line

22
Q

What are t tubules

A

Invaginations, folds of the sarcolemma, to bring the action potential closer to the sarcoplasmic reticulum

23
Q

Draw a sarcomere

A

Think light for I band
Think dark for a band

I band
A band
H sone
M line
Z line

24
Q

Sliding filament theory

A

Myosin and actin slide over each other to contract
Sarcomeres get shorter
A band sAme length
H zone and I band shorter

25
What is a motor unit
Motor unit is a motor neurone together with all the muscle tissues it innervates A single Somatic motor neurone can innervate a few muscle fibres
26
Identify the special adaptation of muscle fibres that support synchronous contraction of sarcomeres.
T tubules and a lot of calcium ions Sarcolemma has invaginations into sarcoplasm to form membranous t tubules. Depolarisation of the sarcolemma of the muscle fibre is rapidly disseminated throughout the sarcoplasm by the T tubule system. T-tubules permit rapid transmission of the action potential into the cell Sarcoplasmic reticulum has a lot of calcium ions concentrated within. release of Ca 2+ ions from the sarcoplasmic reticulum into the sarcoplasm surrounding the myofilaments; Ca 2+ ions then activate the sliding filament mechanism as described above, resulting in muscle contraction. This helps with synchronous contraction
27
Structure of cardiac muscle
- One or two nuclei Centrally located - Has intercalated discs where cell cell communication occurs (gap junctions and desmosomes ) - only found in heart - shorter cylindrical - striated - branched
28
3 layers of heart wall
Endocardium (endothelial cell, single layer) Myocardium (cardiac muscle tissue) Pericardium (outer supporting tissue layer)
29
Structure of cardiac muscle
Cardiomyocytes Reticular connective tissue that supports rich capillary network Cardiac tissue ie myocardium (muscle tissue) Intercalated discs that anchor cardiac cells together
30
Conducting system of the heart
- SAN - AVN - Bundle of His Purkinje fibres
31
Pacemaker of the heart
Sinoatrial node
32
What is the function of intercalated disc
Gap junctions and desmosomes provide points of anchorage for the myofibrils but also permit extremely rapid spread of contractile stimuli from one cell to another. Thus, adjacent fibres are triggered to contract almost simultaneously, thereby acting as a functional syncytium
33
Difference between skeletal muscle and cardiac muscle
Check one note
34
Why does sarcoplasmic reticulum leak calcium slowly in cardiac muscles
Generate its own action potentials Causes succession of automatic contractions independent of external stimuli
35
Structure of smooth muscle
Single, centrally located nuclei No sarcomeres so no striations No myofibrils Elongated, spindle-shaped cells Actin and myosin are arranged in criss cross lattice
36
Function of smooth muscle
- continuous contraction - lines the lumen of hollow organs like GI tract - peristalsis, propels lumen contents
37
Describe peristalsis
Inner circular constricts and the outer longitudinal shortens Long contractions of High force, stronger force than skeletal muscles Parasympathetic (rest and digest) ganglia of the autonomic NS modulated intensity of peristalsis
38
How does smooth muscle contract?
Elongated -> globular shape The thick and thin filaments are attached to dense bodies, which are attached to the plasma membrane by intermediate filaments. This type of muscle responds to a increase in calcium, following nerve stimulation through a protein called calmodulin. Binding of calcium to calmodulin (2nd messenger), results in the activation of an enzyme (myosin light chain kinase) that phosphorylates myosin, which activates it, enabling it to interact with actin.
39
Which muscles tissue types have gap junctions
Smooth and cardiac
40
Dense bodies
Anchor smooth muscle to cytoplasm and cell membrane