Muscle+Physiology

= Muscle Physiology =

In chapter 12 we learned about muscle of the body and movement of those muscles.

http://www.daviddarling.info/images/skeletal_muscle.jpg

Skeletal muscles are made up of muscle fibers that contract when stimulated by a motor neuron. Muscles can contract or extend. The prime mover of a muscle during a muscle contraction is called the agonist. The antagonist works opposite the agonist. Skeletal muscles are striated in appearance.

Motor unit- each somatic motor neuron and all the muscle fibers that it innervates

http://www.shoppingtrolley.net/skeletal%20muscle_clip_image003.jpg

Contraction- Sliding filament theory

[|Sliding Filament Theory] [|contraction of a muscle]

These two links give a great explanation of muscle contraction and the sliding filament theory. It also shows how Ca is needed to start the sliding filament theory and ATP- energy is need to bind the Ca in order to cause the myosin to bind to the actin.

Muscle Relation- The calcium release channels must close to stop contraction. This moves Ca from the sarcoplasm into the sarcoplasmic reticulum. ATP is needed for relaxation as well as contraction.

When a muscle contract this causes the muscle to shorten, which creates tension. The muscle must be stronger than the load to be able to preform work.

Types of muscle contractions Isotonic- - the contraction strength is constant at each load Isometric- the muscle stays at one lenght

Contraction can either be concentric- most work or eccentric- resisting gravity

Aerobic capacity- requires oxygen- longer time period or exercise. Anaerobic is exercise without oxygen. This is very short periods of quick powerful movement. There are different types of muscle fibers.

Type I fibers- slow twitch- great for longer period of exercise- long distance running Type II fibers- fast twitch- great for short bursts of energy- for power or strength- sprinting, weight lifting

Golgi Tendon


http://www.colorado.edu/intphys/Class/IPHY3430-200/image/13-6b.jpg

This image above explains how the gogi tenon organ protects the tendon from stretching too far.

Excitation-Contraction Coupling [|Excitation-Contraction]

Personal Application: This chapter is very relevant and useful to me in my field. In the past I was a personal trainer and I was well educated on the skeletal and cardiac muscle actions. I will use this information in the future as a PTA in prescribing exercise prescriptions to my clients and creating home exercise programs to improve their function.

Questions? The sliding filament theory- Motor neuron stimulates a muscle fiber, the calcium ions are released from the SR- Sarcoplasmic reticulum. Causing the Tropomyosin to displace exposing binding sites on the actin molecules. Globular heads on the myosin bind to these sites forming crossbridges. This causes the muscle to contract this process requires ATP for energy. Muscle relaxation- the calcium release channels must close to stop contraction. This moves Ca from the sacrcoplasm into the sarcoplasmic reticulum. ATP is need for relaxation as well as contraction.  References: All information contained in this wiki was obtained from sited websites and Human Physiology, by Stuart Ira Fox.