Lecture 15 - Contraction Flashcards
What do forces do?
move levers about axes
What are the 3 types of Human muscle tissue?
- Smooth Muscle
- Cardiac Muscle
- Skeletal Muscle
What is smooth muscle?
- involuntary
- blood vessels, organs, iris
What is cardiac muscle?
- involuntary
- self-generating impulses
- features of smooth and skeletal muscle
- fatigue resistant
What is skeletal muscle?
- striated (looks striated under a microscope)
- connects body segments by tendons
- voluntary (volitional)
What is a muscle cell?
- size of a thin human hair (can be 12cm (4.5 inches)
- multinucleated cylindrical cell
what is the sarcolemma?
the cell membrane
- porous
- electrical impulse travels down it to create a muscle contraction
What is sarcoplasm?
cytoplasm of the muscle cell
myofibrils are what?
the content of a muscle fibre that is made of contractile proteins
What does actin do for a muscle cell?
Actin is thin filament, forms the framework, slides over myosin filaments
what is the sarcomere?
“functional” unit of a muscle fibre, they shorten when the muscle contracts
What is the sarcoplasmic reticulum?
labyrinth of tubules inside muscle fibre
What connects the sarcoplasmic reticulum with the sarcolema?
T-tubules - transverse tubules
What are the myofibrils, fibres, and bundles of fibres surrounded by in the muscle?
connective tissue
What is connective tissue made of?
Collagen
Why are muscles attached to bones?
to create movement
What are tendons?
strong fibrous tissues that attach muscle to bones
What are myofilaments?
myosin and actin
what drives a muscle to contract?
A nerural impulse - in the form of an action potential
What are neural impulses?
electrical currents that pass along nerve fibres
What is a motor unit?
when motor nerves innervate many muscle fibres
What do impulses cross between adjoining nerves?
Synapses
What do impulses cross to innervate muscle?
Motor end plate
What neurotransmitter is used to cross gaps?
Acetylcholine
What order do impulses travel in?
- over the sarcolemma
- through the & tubules
- cause calcium to release from storage in sarcoplasmic reticulum
What causes a contraction to stop?
- when a neural impulse is absent and calcium is reabsorbed into the sarcoplasmic reticulum
