L: Structure of skeletal, cardiac and smooth muscle

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Which type of muscle is involved in body movement and body posture?

Skeletal muscle

Which type of muscle is involved in sphincter control?

Skeletal and smooth muscle

What type of muscle is involved in movement of food along the GIT?

Smooth muscle

Which types of muscle are involved in the regulation of blood flow?

Cardiac muscle pumps blood and smooth muscle in the vessel walls regulates blood flow.

Which muscles are involved in temperature regulation?

Skeletal muscle (shivering) and smooth muscle (erection of hairs)

What does the muscle characteristic excitability mean?

The responsiveness to stimuli

What does the muscle characteristic contractility mean?

The ability to shorten forcibly when adequately stimulated.

What does the muscle characteristic extensibility mean?

The ability to extend beyond their resting/relaxed length

What does the muscle characteristic elasticity mean?

Able to recoil and resume its resting length after stretching.

What type of movement is isometric?

A static hold

What type of movement is concentric?

The muscle shortens

What type of movement is eccentric?

The muscle lengthens

What is another name for aerobic respiration?

Oxidative respiration

What is another name for anaerobic respiration?

glycolytic respiration

Which type of respiration is a short term method of generating ATP?

Glycolytic respiration

What element ions are used to active contraction?

Calcium ions

What is needed for muscle stimulation?

Action potential from a neurone

What components of a myocyte generate force for contraction?

Actin and myosin.

What is the cell membrane of a muscle cell called?

Sarcolemma

What is the cytoplasm of a muscle cell called?

Sarcoplasm

What is endoplasmic reticulum of a muscle cell called?

Sarcoplasmic reticulum

What are examples of myofibrils?

Actin and myosin

What percentage of muscle protein do actin and myosin make up?

90%

What type of protein are actin and myosin?

Enzymes

How many skeletal muscles are there?

640

What percentage of body mass do skeletal muscles make up?

40%

What size are skeletal muscle cells?

Large - (100 um - 600 um)

Are skeletal muscle cells multinucleated?

yes

Is the control of skeletal muscle voluntary or reflexive?

Both

Is contraction of skeletal muscles sporadic or continual?

Can be both

What is the function of tendons?

Attached muscle to bone and maintains structural integrity

What are the layers of connective tissue that form tendons?

Epimysium, perimysium, endomysium

What is a fascicle?

A grouping of elongated bundles of muscle fibres (cells)

What is the endomysium?

Connective tissue (mostly collagen) that separates the muscle fibres

What is the perimysium?

Loose collagenous tissue that surrounds the fascicles.

What is the epimysium?

Dense collagenous tissue (sheath) that surrounds the whole muscle

What causes striations?

Overlapping actin and myosin myofilaments

What are other names for muscle cells?

Myocyte/myofibre

What are myofilaments?

actin and myosin

What structure gathers Ca+ ions?

The sarcoplasmic reticulum

What control is cardiac muscle - voluntary or involuntary?

Involuntary

What does a synctium mean and what muscle contracts as one?

Contracts all together or not at all - cardiac muscle

What does it mean to say that cardiac muscle cells are autorhythmic?

They do not require neuronal stimulation to contract

What nervous system coordinates cardiac muscle?

The autonomic nervous system

Are cardiac muscle cells branched or non branched?

Branched

is cardiac muscle striated or non-striated?

It is striated

What size are cardiac muscle cells?

Small - (100um in length)

What percentage of cardiac cell volume do mitochondria make up?

25-35%

What type of respiration does cardiac muscle use?

Aerobic respiration

What specialised junctions do cardiac muscle cells have and what type of junctions make them up?

Intercalated discs - desmosomes and gap junctions

What is the function of desmosomes between cardiac muscle cells?

Strong anchoring to help prevent cells pulling apart

What is the function of gap junctions between cardiac muscle cells?

Allows rapid electrical signal transmission.

What are gap junctions formed by?

Connexons - 6 subunits

Is the electrical resistance of gap junctions low or high?

Low

What is the function of smooth muscle in blood vessels?

Regulates lumen diameter - contributes to maintenance of blood pressure

What is the function of smooth muscle in the digestive tract?

Rhythmic peristalsis propels food

What type of muscle is present in the skin?

Smooth muscle

What size are smooth muscle cells?

Small - (100-200um in length)

What shape are smooth muscle cells and how are they arranged?

Spindle shaped and arranged into sheets

Is smooth muscle striated or non-striated?

Non striated

Are smooth muscle cells multinucleated or not?

They have a single nucleus

What is the control of smooth muscle cells?

Involuntary

What systems control smooth muscle?

Autonomic nervous system, hormones and stretch

How are the sheets of smooth muscle arranged?

Perpendicular to each other

How are actin and myosin anchored in smooth muscle cells?

Via dense bodies throughout the sarcoplasm

What junction electrically connects smooth muscle cells?

Gap junctions

What junction structurally connects cells?

Focal adhesions

Which muscle type has the slowest contraction rate?

Smooth muscle - also longer duration

What respiration does skeletal muscle have?

Aerobic and anaerobic

What respiration does smooth muscle have?

Mainly aerobic respiration