The Physiology of Muscle Contractions

The Physiology of Muscle Contractions

All muscles require fuel (energy substrate) in order to contract.

The ______source is carbohydrates.

Fatty acids (a component of fats) can be used but the process is more ______and the steps are more tedious.

Proteins are the ______fuel source. They are better used for organ structure, blood components and muscle tissue.

Energy for Contractions

Quick energy for muscle contraction is made by the Creatine-Phosphate ______(CrP) system.

This system moves the P from CrP to ______and regenerates ______.

The CrP is found in muscle cells in limited quantity and comes from our ______.

This system produces ____ ATP for every CrP molecule.

Short-term energy needs are met by breaking down ______in the ______. This process is called ______* (glucose – splitting).

In the absence of glucose, it is necessary to first convert ______into glucose through a step called glycogenolysis (glycogen – splitting) and then proceeding with glycolysis*

Glycolysis* is an 11-step event that will produce ____ ATPs as well as a by-product called lactic acid.

* Oxygen is not present in the cytosol, so glycolysis is also known as anaerobic respiration.

Primary energy needed for continuous muscle contraction comes from the ______that is produced by

______.

This method only provides energy as long as there is available ______and ____.

Aerobic respiration produces ______ATP/glucose molecule.

Anatomy of Skeletal Muscle(special nomenclature)

Because of it’s shape, the muscle cell is called a ______

1. the cell membrane is called the sarcolemma

2. each fiber is filled with ______

Myofibrils are composed of contractile units or sections called ______

1. each sarcomere is composed of two types of protein filaments known as: myofilaments -

thick and thin filaments

2. the ______composes the ______

3. the ______composes the ______

Anatomy of Skeletal Muscle

Each myosin molecule has a rod-like extension that ______.

The myosin heads reach out and ______and form a temporary connection withthe actin myofilaments during contraction. This action requires ______.

When muscles contraction occurs the ______.

1. The actin molecules are pulled ______of the sarcomere.

2. When multiple sarcomeres shorten, the entire ______fiber is ______.

Contractions and Calcium

Muscle contractions require the presence of ______and of______.

Normally, troponin blocks the active sites on actin

Calcium ______with and ______of troponin.

By moving troponin out of the way, the active sites on actinis ______, this gives myosin a place to bond and cause a muscle contraction.

The contraction ends when ATP degrades to ______and magnesium forces the release of calcium.