Chapter 17 Flashcards
Muscles 3 general functiond
Enables the body and its parts to move
Heat prodcution
Posture
3 functional characteristics of skeletal muscle
Excitability
Contractility
Extensibility
Excitability meaning
Ability to be stimulated
Contractility meaning
Ability to contract/ shorten movement
Extensibility meaning
Ability to extend/ stretch, allowing muscle to return to their resting length
THREE TYPES OF MUSCLE TISSUE
Skeletal
Cardiac
Smooth
Skeletal muscle is also called _____ or ______
Striated or voluntary
Skeletal muscle represents ____ to______ of body weight
40-50%
Skeletal muscle is attached to ____
Bones
Skeletal muscle has _________ striations and __________ contractions
Microscopic striations
Voluntary contractions
Skeletal muscle has ____________ cell/fiber that are arranged ________
Multinucleated
Around periphery of cell
Skeletal muscle cells are called
Fibres
Plasma membrane of muscle cell is called
Sarcolemma
Cytoplasm of skeletal muscle cell called
Sarcoplasm
The endoplasmic reticullum of the skeleton muscle is called ______ and the membrane is responsibe for ________
SarcOPLASMIC reticulum (SR)
Responsible for calciuam release and storage
Muscle fibres contain many _____ , ______, _______ and have inward extensions of the sarcolemma called _____
Mitochondria, nuclei, myofibrils,
T-tubules
What are myofibrils
Numerous fine fibres packed together in the sarcoplasm
What do t-tubules allow?
Allow nerve impulses to move deeper into the fibre
Myofibrils are made up of very fine thread like structures called
Myofilaments
_____ types of proteins make up myofilaments
4
2 main types of proteins that make up the myofilaments
Myosin
Actin
Myosin makes up most of the ______ myofilaments
Thick
Actin makes up most of the _______ myofilaments
Thin
Actin and myosin are arranged in repeating segments called
Sarcomere
A sarcomere is the basic functional unit of _____
Muscle fibres
Individual sarcomeres are seperated by
Z-lines (Z disks)
A skeletal muscle fibre will stay at rest until
It is stimulated by a nerve impulse which arrived via a motor neurons
The nerve impulse travels along the motor neuron until it reaches the
Neuromuscular junctino
A synapse is
Microscopic gap between the end of motor nueon and sarcolemma of the fibre
To transmit the nerve impulse across the synapse, what must be released
Nuerotrainsmitter
Where do neuro transmitters bind when they are released
The muscle fibres sarcolemma
What is the result of nuerotransmitters binding to the sarcolemma?
Excitation of sarcolemma, sending a nerve impulse resulting in calcium ions to be released into the sarcoplasm
4 Steps of muscle movement
- Each myosin head in the thick filament moves into a resting position after an ATP molecule binds and transfers its energy
- Calcium ions released from the sercoplasmic reticulum bind to troponin in the thin filament thereby allowing tropomysin to shift from its position blocking the active sites of actin molecules
- Each myosin head then binds to an active site on thin filaments and displaces the remnants of ATP hydrolysis- ADP & Pi
- The release of stored energy from step q provides the force needed for each head to move back to its original position and pull actin along with it. Each head will remain bound to actin until another ATP molecule binds to it and pulls it back into its resting position.
During contraction, _____ binds to actin forming _______ which acts as levers to pull the ______ past eachother
Myosin
Cross bridges
Myofilaments
As muscle contracts, _________ slide past each other
Myofilaments
Contraction requires _______ (for cross bridge formation) and _____
calcium
Atp
SR actively removes _____ to stop contraction
Calcium
Whole blood is
55% plasma
45% formed elements
Seperated by buffy coat
