The Muscular System home study course

Transcription

1 The Muscular System home study course harmony house holistic therapy treatment centre and training academy

2 1 Copyright 2010 by Mark and Katy Rogers All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the Copyright owner Harmony House, or any other persons who have been involved in working on this publication, cannot accept responsibility for any injuries or damage incurred as a result of following the information, exercises, or therapeutic techniques contained in this book.

3 2 Table of Contents The Muscular System...3 The Muscular System...3 Voluntary Muscle...4 Muscle contraction...5 Muscle fatigue...6 Muscle tone...7 Tendons...7 Muscles of the body....8 Trapezius...8 Upper arm anterior...9 Upper arm posterior...10 Anterior of the trunk...11 Muscles of respiration...12 Posterior of the trunk...13 Anterior of the lower limb...14 Posterior of the lower limb...15 Psoas...16

4 3 The Muscular System The Muscular System The muscular system has three main functions:- Movement Muscles pull on bones at joints to create movement. Muscles also help to move around body fluids such as blood, lymph and urine. Maintaining posture Some muscle fibres resist movement and create a slight tension in order for us to maintain posture, such as standing upright or sitting down. The production of heat As muscles move they create heat as a byproduct. This helps to maintain our body temperature. There are three types of muscle tissues:- Skeletal or voluntary muscle which is primarily attached to bone and is responsible for causing voluntary movement. Cardiac muscle is found in the heart and is responsible for causing the heart to expand and contract and thus pump blood through the blood vessels and around the body. It is under involuntary control. Smooth or involuntary muscle is found in blood vessels, the digestive system and the urinary tract. Muscle tissue makes up about 50% of your body weight, and is composed of 20% protein 75% water 5 % mineral salts, glycogen and fat.

5 4 Voluntary Muscle Myoblasts are responsible for forming muscle fibres, which collectively form the muscles themselves. Muscle fibres contain threadlike structures called myofibrils, which extend from one end of the fibre to the other. Each myofibril is made up of even smaller thread or filaments of protein called myofilaments. There are two types of myofilaments:- 1. Actin thin filaments 2. Myosin thick filaments Also present in the muscle fibres are mitachondria. These are the powerhouses of the muscle as they generate the energy required to make the muscle move. These store glycogen and myoglobin. Glycogen is needed for energy and myoglobin holds the oxygen brought to the muscles from the respiratory system, and is needed to active the energy. Muscle fibres are surrounded by connective tissues called endomysium, which provides support. Groups of muscle fibres make up bundles, which are surrounded by more connective tissue called perimysium, which provides more support. Bundles of muscle fibres are arranged in groups to form complete muscles, which are covered by another layer or fascia of connective tissue called epimysium.

6 5 Muscles contain a rich blood supply to ensure that the fibres are provided with fuel, and a nerve supply linking the muscular system to the brain in order to allow movement instructions to be carried out. Muscle contraction There are two types of muscle contraction:- Concentric contraction shortening of the muscle Eccentric contraction lengthening of the muscle. When a muscle shortens (concentric contraction), the actin and myosin filaments overlap pulling the muscle fibres together to make a bulky middle. The opposite occurs when the muscle contracts eccentrically, the actin and myosin filaments move away from each other. The force of the contraction depends on the number of fibres contracting at the same time. The greater the number of fibres contracting, the greater the force. Muscles are made up of different types of fibre :- Slow twitch fibres produce slow contractions with low levels of speed and power over long periods of time (aerobic) Fast twitch fibres produce fast contractions with high levels of speed and power for only a short period of time (anareobic). Voluntary muscles are moved as a result of nervous stimulation which they receive from the brain via a motor nerve. The site where the nerve fibre and muscle fibre meet is called a neuromuscular junction. In response to a nerve impulse, the end of the motor nerve fibre secretes a neurotransmitter, which diffuses across the junction and stimulates the muscle fibre to contract.

7 6 Muscles require energy to perform contractions. This energy is provided in three :- The aerobic energy system glycogen is stored in the mitochondria in the muscles, plus oxygen in the myoglobin brought to the muscles from the respiratory system, create ATP (Adenosine Triphosphate) by oxidation. ATP is the chemical fuel needed to make movement in a muscle. As a result of this action a waste product pyruvic acid is produced. This reacts with the oxygen to produce more energy. The other waste products produced are carbon dioxide and water. The anaerobic energy system When the need for energy is high, more pyruvic acid than the oxygen can cope with is produced. The excess is turned into lactic acid which build up and causes fatigue resulting in breathlessness and aching muscles. When the need for energy reduces, the body takes deep breathes, brining more oxygen to the muscles. Carbon dioxide, water and lactic acid are removed by the circulatory system. The latic acid is broken down into glycogen by the liver to be used as energy at a later date. A small amount of energy is stored in the mitochondria in the muscles in the form of ATP which can be used for short bursts of energy only before one of the other two methods kicks in. Muscle fatigue Muscle fatigue is caused by the build up of latic acid in the muscle, which causes the muscle to ache, and is defined as the loss of ability of the muscle to contract efficiently due to insufficient oxygen, exhaustion of energy supply and the accumulation of latic acid.

8 7 Muscle tone When a muscle is relaxed some fibres contract to sustain the certain amount of firmness, this is known as muscle tone and is important for maintaining body posture. Good muscle tone is recognised by muscles appearing firm and rounded. Poor muscle tone is recognised by the muscles appearing loose and flat. Muscles with a less than normal degree of muscle tone are said to be flaccid, when muscle tone is greater than normal the muscles become spastic and rigid. Tendons Tendons are tightly woven, white, glistening, tough fibrous bands or cords that link muscle to bone. They are not elastic, rather relatively inflexible. A tendon s blood supply is limited, so the do not heal quickly. They are mechanical strong and the primary role is to transmit the contractile force of the muscle to the bone. They are strongest in the direct of the tensile stress.

9 8 Muscles of the body. Trapezius Position Large triangle shaped muscle in upper back that extends from the base of the skull, the cervical vertebrae and the thoracic vertebrae to scapula. It is arranged in three groups, upper, middle and lower. Action The upper fibres raise the shoulder girdle The middle fibres pull the scapula toward the vertebral column The lower fibres draw the scapula and shoulder downward.

10 9 Upper arm anterior. Muscle Position Action Bicep Front (anterior) of humerus. Flexes the forearm at elbow joint. Supinates forearm Brachialis Lies beneath the bicep Flexes the forearm at the elbow Brachioradialis Connects the humerus Flexes the forearm at Flexor carpi radialis Flexor carpi ulnaris Flexor carpi digitorum to the radius Extends along the radial side of the anterior forearm Extends along the ulnar side of the anterior forearm Extends from the medial end of the humerus, the anterior of the ulnar and radius to the anterior surface of the 2 nd to 5 th fingers the elbow Flexion of the wrist Flexion of the wrist Flexion of the fingers

11 10 Upper arm posterior Muscle Position Action Deltoid Triangular muscle that caps the top of the humerus and shoulder Triceps Back (posterior) of the humerus Abducts the arm, and draws the arm backwards and forwards Extension (straightening) of the forearm

12 11 Anterior of the trunk Muscle Position Action Pectoralis major A thick fan shaped muscle covering the anterior surface of the chest External obliques Pectoralis minor Serratus anterior Rectus abdominis Internal oblique A broad thin sheet of muscle whose fibres slant downwards from the lower ribs to the pelvic girdle, and linea alba (tendon running fro the bottom of sternum to the pubic symphysis) This is a thin muscle that lies beneath the pectoralis major A broad curved muscle the located on the side of the chest / ribcage. A long strap like muscle that attaches from the ribs and sternum to the pubic bones A broad thin sheet of muscle located beneath the external obliques. Its fibres run up and forward from the pelvic girdle to the lower ribs Adducts and medially rotates the arm. Flexes, rotates and side bends the trunk. It compresses the contents of the abdomen Draws the shoulder down and forwards Pulls the scapula downwards and forwards Flexes the vertebral column, flexes the trunk (sit up). Compresses the abdominal cavity Flexes, rotates and side bends the trunk. It compresses the contents of the abdomen

13 12 Muscles of respiration External intercostals Internal intercostals Diaphragm Muscle Position Action External Intercostals Superficial (outside) muscles that occupy the space between the ribs Internal Intercostals Diaphragm Deep (inside) muscles that occupy the space between the ribs A dome shaped muscle that separates the thorax from the abdomen Elevate the ribcage to aid during inhalation Depress the ribcage to aid in exhalation On contraction the diaphragm flattens to expand the volume of the thoracic cavity to assist inspiration. Upon relaxation and expiration it returns to its dome shape

14 13 Posterior of the trunk Muscle Position Action Latissimus dorsi Covers either side of the back from the underarms to the lumbar region. Erector spinae Quatratus lumborum Gluteus maximus Gluteus medius Gluteus minimus Group of muscles that extend along the spine at the centre of the back from the neck to the pelvis The muscle attaches to the posterior of the iliac create at one end and to the twelfth rib and transverse processes of the first four lumbar vertebrae This is a large muscle that covers the buttock Partially cover by the gluteus maxixmus, it attaches to the outer edge of the iliac at one end and the outer surface of the femur at the other This muscle lies beneath the gluteus medius. It has the same attachments. Extends, adducts and rotates the humerus medially Extension, lateral flexion and rotation of the vertebral column Lateral flexion (sidebending) of lumbar vertebrae Extends the hip, abducts and laterally rotates the thigh Abducts and medially rotates the thigh Abducts and medially rotates the thigh

15 14 Anterior of the lower limb Muscle Position Action Quadriceps (rectus fermoris, vastus lateralis, vastus intermedius, vastus medialis) Form the front of the thigh Sartorius Adductors of the upperleg (Gracilis, adductor brevis, adductor longus, adductor magnus, pectineus) Tensor fascia lata Tibialis anterior Crosses the front of the thigh from the outside of the pelvis to the inner side of the knee Four muscles of the inner thigh. Attached to the lower part of the pelvic girdle at one end and the inside of the femur at the other This muscle runs laterally down the side of the thigh Forms the shin at the front of the lower leg As a group they extend the knee and flex the hip Flexes the hip and knee and laterally rotate the thigh (turn the knee outwards) Adduct and laterally rotate the thigh, Flexes the hip and knee. Flexes, abducts, and medially rotates the thigh Dorsiflexes and inverts the foot

16 15 Posterior of the lower limb Muscle Position Action Hamstrings (semitendinosus, semimembranous, bicep femoris) Group of three muscles form the back of the thigh from the pelvis to below the knee Gastrocnemius Soleus Plantor flexors of the foot. (Peroneus longus, Flexor digitorum longus, Flexor hallucis longus) Forms the bulk of the calf at the back of the lower leg, has two bellies, Lies below the Gastrocnemius from below the back of the knee to the calcaneum via the Achilles tendon Run from the back of the fibula of tibia to the metatarsals or toes Flex the knee and extend the hip backwards (as needed for walking and jumping) Plantar flexes the foot and assists in knee flexion Plantar flexes the foot Plantar flexion and evert and inversion of the foot

17 16 Psoas Muscle Position Action Psoas A long deep pelvic muscle, attaches to anterior processes of T12 L5 and to the inside of top of femur at the other end. Flexes the thigh