muscle physiology report

Experiment 11

MUSCLE PHYSIOLOGY

Capistrano Fernando Fuentes Jose Lopez Manilay Manrique Nicolas Rempillo Valeza

MUSCLE CONTRACTION

process which leads to shortening or development of tension on the muscles

can be studied through application of a stimulus to a muscle.

An apparatus consisting of a rotating drum for recording nerve-like motions, variations or modulations, such as muscular contraction.

Kymograph

Myograms showing the effects of different frequencies of stimulation. (a) Simple twitch. (b) Treppe or Staircase effect. (c) Summation. (d) Tetani. The arrow indicates the time at which the stimulus occurred.

Muscle Twitch

A muscle twitch is a muscle contraction in response to a single stimulus of adequate strength.

Three Phrases of a Muscle Twitch1. Latent period

2. Contraction phase

3. Relaxation

Treppe

• The frequency of stimulation was so slow here that relaxation was complete betweencontractions.

• The strength of contraction did increase because muscle contraction causes heat to build up in the muscles and muscles then work better when they are warmer. Enzymes can work faster and more efficiently when a muscle is "warmed up".

Summation

• Now the frequency of stimulation is increased to the point where relaxation cannot totally occur.

• The result is a continual increase in tension which may result from increased availability of intracellular calcium.

Incomplete tetanus

• Now the frequency of stimulation is increased to the point where the muscle exhibits even shorter contraction-relaxation cycles, but there is still some degree of relaxation after each contraction.

Complete tetanus• When the frequency of stimulation becomes fast enough, the contractions fuse into a smooth, continuous, total contraction with no apparent relaxation.

RINGER’S SOLUTION

-a solution of recently boiled distilled water containing 8.6 g sodium chloride, 0.3 g potassium chloride, and 0.33 g calcium chloride per liter – the same concentrations as their occurrence in body fluids.

Ingredients are: 6g NaCl, 0.075g KCL 0.1g CaCl2 0.1g NaHCO3

•Prolongs excitability and avoids desiccation of muscles

•Keeps the body organ functioning outside the body for an ample amount of time by providing electrolytes to living material.

•Washes away lactic acid

Functions of Ringer’s Solution

The muscle twitch has three different parts. Latent period (2msecs): This part of the muscle twitch begins as soon as the muscle receives stimuli.

Period of Contraction (15msecs): The tension within the muscle rises to its peak.

Period of Relaxation (25msecs)

In summation, why is the second contraction higher than the first?

Because of the additional influx of calcium ion that promotes a second contraction, which is added to the first contraction

What is the physiological basis of the “warming up” period required of athletes?

Warm-up also causes increased blood flow to the muscle (saturate with oxygen and nutrients) and increased muscle temperature (enzymes functions at a faster rate)

***Treppe is achieved during warm-up exercises greater muscle efficiency

Differentiate complete from incomplete tetanus.

In complete tetanus, there is no relaxation phase between stimuli while in incomplete tetanus, there occurs a partial relaxation between stimuli.

Fatigue One of the abnormalities in Skeletal Muscle Function is Muscle Fatigue. It is the physiological inability of the muscle to contract. One factor is the failure of the muscle to generate sufficient ATP.

Referenceshttp://www.aw-bc.com/info/ip/assignmentfiles/muscular/Contraction_of_Whole_Muscle.pdf

http://www.whonamedit.com/synd.cfm/2119.html

http://en.wikipedia.org/wiki/Muscle