Muscular System Flashcards
Types of muscle tissue
Skeletal
Cardiac
Smooth
Skeletal muscle description
Usually attached to bone
Long, cylindrical, multinucleate cells
Obvious striations
Skeletal muscle function
Voluntary movement
Locomotion
Manipulation of the environment
Facial expressions
Voluntary control
Skeletal muscle location
Attached to bones and occasionally skin
Cardiac muscle description
Branching, striated, uninucleate cells
Interdigitate at specialised junctions (boosts nerve impulses)
Autorhythmic
Cardiac muscle function
Contraction causes blood to be propelled into the circulation
Involuntary control
Cardiac muscle location
Walls of the heart
Smooth muscle description
Spindle-shaped cells - allows wave-like contractions
Central nuclei
No striations
Cells arranged closely to form sheets
Smooth muscle function
Propels substances and objects along internal passage-ways
Involuntary control
Smooth muscle location
In the walls of hollow organs
Functions
Movement
Posture
Regulating organ volume - e.g. stomach
Moving substances in the body - e.g. heart; blood
Heat production - muscle contraction
Characteristics - excitability (irritability)
Ability to respond to a stimulus
Characteristics - contractility
Ability to contract when stimulated from a nerve impulse
Characteristics - extensibility
Ability to be stretched or extended
Characteristics - elasticity
Ability to return to the original length after stretching
Muscle attachment - origin
One end of the muscle is attached to a structure (usually bone) that remains stationary
Muscle attachment - insertion
The opposite end of the muscle to the origin that is moved by the contraction
Antagonistic pairs
One contracting (shortening) while the other relaxes (lengthening)
Agonist
Prime mover
Contracts to cause an action
Antagonist
Stretched and yields to the action of the agonist
Opposing force
Synthergist
Contract to stabilise intermediate joints
E.g. brachialis (at elbow) during bicep curl
Fixator
Stabilise the origin of the agonist
Anatomy of skeletal muscle - fascicle
Muscle fibre cells
Makes bundles
Anatomy of skeletal muscle - epimusium (connective tissue)
Surrounds the whole muscle
Anatomy of skeletal muscle - perimysium (connective tissue)
Surrounds the bundles of fibres (fascicle)
Anatomy of skeletal muscle - endomysium (connective tissue)
Surrounds individual muscle fibres
Anatomy of skeletal muscle - myofilaments
Contractile protein, actin and myosin
Myofilaments make up myofibrils which makes up each muscle fibre
Overlapping of thin actin and thick myosin
Gives muscles striated appearance
ATP production - creatine phosphate
Stored in muscles
Coupled reaction
Creatine kinase
No oxygen
1 ATP per creatine phosphate
15 seconds
ATP production - anaerobic respiration
- Glycolysis
- Lactic acid formation
No oxygen
2 ATP per glucose
60 seconds
ATP production - aerobic respiration
- Glycolysis
- Krebs cycle
- Oxidative phosphorylation
Uses oxygen
32 ATP per glucose
CO2 and H2O
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