Chapter 6 anatomy and physiology for massage therapy
A muscle contraction occurs when _____________, allowing myosin to pull itself along, increasing the overlap of the two myofilaments, and shortening the sarcomere
A chemical bond is formed between the actin and myosin myofilaments that pull them together and increases the overlap between them
Explain the length-strength ratio
A muscle that is already shortened will also be weak, because sarcomere is already shortened and overlap is maximized, leaving little room for sliding
A motor unit is made of
A single nerve cell called a motor neuron and multiple muscle fibers it innervates
Fascia is the tough yet pliable sheet of _________________ that covers, divides and supports all the structures of the body
Connective tissue
When threshold stimulus is reached ____ the muscle fibers in that motor unit fully contract.
All
ATP provides energy for the cells of the body to do their work by:
Breaking the bond of the third phosphate and using energy of the bond to do work/which creates ADP
Only a small amount of ATP is floating around inside muscles cells at any given time, so if activity persists for more than a few seconds the cell must use one of three methods to get more
Creatine phosphate, anaerobic cellular metabolism, and aerobic cellular metabolism.
Anaerobic cellular metabolism
Glucose obtained from blood or the breaking down of glucose stored within muscle
Muscle fatigue
Is the inability of muscle to contract forcefully after prolonged activity even when stimulated to do so.
Some reasons for muscle fatigue are
Lack of oxygen, depletion of glycogen, decreased in calcium supply needed for myofilament bonding.
The primary functions of the muscular system are
Movement of body parts, posture, stabilization of joints, and production of heat
Creatine phosphate
Muscle activity increases, phosphate ions are broken off of ATP molecules to release energy, leaving two phosphate ions behind and creates ADP
The central portion of every muscle is the ____________
Muscle belly
If less than the threshold is transmitted, ____ of the fibers contract. This applies to to the individual motor unit, not the whole muscle.
None
Skeletal muscle fibers have more than one _______ and two or three times as many ____________
Nucleus; mitochondria
Aerobic cellular metabolism
Oxygen is made available to muscles from oxygen-binding proteins either in blood or stored in muscle fibers.
Muscle tissue is "excitable" meaning it is designed to:
Respond quickly to simulation from the nervous system
Because the muscles of the body make up the majority of our "flesh" the prefix ______ is used to name cell features as a way of saying you are specifically talking about muscle
Sarco
The cytoplasm is called __________
Sarcoplasm
When a muscle or tendon is injured, we call that a ______
Strain
Muscle attaches to bone via cord-like ______ or a broad flat sheet called ___________
Tendon; Aponeurosis
The place where tendon becomes bone is called _______________________, and the place where muscle becomes tendon is called _________________________.
Tenoperiosteal junctio; musculotendinous junction
The spot where the motor neuron interfaces with a muscle fiber is called
The neuromuscular junction
The physiology of muscle contraction is explained by a model called
The sliding filament mechanism
Retinacula
Thickened superficial bands- holds tendons in place
The minimum amount of stimulation required to produce contraction from the motor unit is called
Threshold stimulus