Human Locomotion

© Lisa Michalek

Locomotion The interaction of muscles with the skeleton that

results in body movement is known as locomotion. Locomotion increases the chances for survival of an

organism by allowing the organism to gather food, seek shelter, and escape dangerous situations.

Locomotion also increases the chances for survival of a species by enabling members of the species to find suitable mates.

Human locomotion involves the interaction of joints and tissues such as bone, cartilage, muscles, tendons and ligaments.

Bones Bone is a type of connective tissue. The hardness of the bone is due to the

presence of calcium and phosphorus minerals.

Bones make up the major part of the framework of the human skeleton and come in many shapes and sizes.

Bones support and protect body organs. Bones also provide a place for muscle

attachment.

Bones The bones of your legs and arms are called

long bones. The ends are covered with cartilage

and are capable of growth. Living bones contain

living blood, fat, and bone cells.

Red and white blood cells are produced in the inner tissue, marrow, of bones.

Human Skeleton The human skeleton acts as a

framework for supporting other organs of the body.

It also protects internal organs and allows body movement.

The human skeleton has 206 bones.

It is composed of a skull, vertebral column (spinal column), breastbone and ribs, and limbs (arms and legs).

Cartilage The fibrous, flexible, elastic connective tissue

found in the human skeleton is cartilage. In the human embryo, the skeleton is made

up mostly of cartilage. By adulthood, most of the cartilage has been

replaced by bone. In the adult, cartilage is found in the nose,

ears, and trachea, at the ends of ribs and other bones and between the vertebrae.

Cartilage At the ends of bones,

cartilage provides flexibility.

Between bones, cartilage provides cushioning.

In the ears, nose, and trachea, cartilage provides flexible, rather than rigid support.

Joints Bones are connected at places called joints. Most joints allow bone movement. Ball and socket joints are located at the

hip and shoulder. They permit circular movement.

Joints Hinge joints are located at the elbows and

knees. They allow a back and forth movement. Hinge joints do not permit as much movement as

ball and socket joints.

Joints Pivot joints are found where the skull

joins the vertebral column. Pivot joints permit a rotating movement.

Joints The wrist and ankle have gliding joints that

allow a sliding action.

Fused joints are not movable and are located in the skull.

Fluids in joints help keep joints cushioned and lubricated.

Muscles The human body contains

three kinds of muscle tissue: Skeletal muscle Smooth muscle And cardiac muscle

Muscles produce body movement by pulling on bones when they contract.

Muscles also produce body heat when they contract.

Muscles can be voluntary or involuntary.

Involuntary Muscles Involuntary muscles are

responsible for involuntary body activities such as heart contractions and peristalsis.

You cannot control the actions of involuntary muscles.

Smooth muscle and cardiac muscle are examples of involuntary muscles.

Involuntary Muscles Smooth muscle is found in

the walls of arteries and organs of the body. Contraction of smooth

muscle is controlled by the nervous system.

Cardiac muscle, found inthe walls of the heart, causes the heart to beat.

Voluntary Muscles Voluntary muscles attach to

the skeleton and can be controlled for locomotion.

Skeletal (striated) muscle is a type of voluntary muscle.

Striated muscles are attached to the bones of the skeleton.

The bones and body parts are moved by the contraction of these muscles.

Muscle Action Nerves direct impulses to muscles causing

them to contract. The energy needed for the muscle to

contract comes from energy stored in chemicals such as glycogen.

Muscle cells will continue to operate even if they do not receive sufficient oxygen.

When the muscle does not receive enough oxygen to carry on aerobic respiration, the muscle cells change to anaerobic respiration.

Muscle Action During anaerobic respiration the muscle cells

produce lactic acid. Lactic acid causes muscles to hurt. This condition is known as muscle fatigue. Rest after exercise supplies oxygen to

fatigued muscle cells. During this rest-recovery period, the lactic

acid is removed and energy-storing compounds are built up again.

If a person does not rest after muscle fatigue, permanent injury to the muscle can occur.

Tendons and Ligaments Tendons and ligaments are both

composed of connective tissue.

Tendons are bands of dense tissue that connect muscles to bones.

Ligaments are tough bands of tissue that hold bones together at joints.

Muscle-Bone Disorders Fractures are broken bones.

Fractures are caused by a sudden injury that exerts more force on the bone than it can support.

The common symptom of a fracture is swelling and tenderness at the place of the fracture.

Pain is often severe and is usually made worse by any movement of the area.

Anyone suffering a suspected or known fracture should be taken to a hospital.

Muscle-Bone Disorders Sprains

A tearing or stretching of the ligaments that hold together the bone end in a joint is called a sprain.

Sprains are caused by a sudden pull or twist.

Because a sprain and a fracture have similar symptoms, the sprain should be x-rayed to be sure that it is not a fracture.

Muscle-Bone Disorders Hernias

In a hernia an organ or tissue sticks out through a weak area in the muscle or other tissue that usually contains it such as the abdominal wall.

The cause is usually a weakness in the wall.

The first symptom is a bulge in the wall.

Muscle-Bone Disorders Arthritis

An inflammation of the joints is called arthritis. Arthritis causes stiffness, swelling, soreness, or

pain. Sometimes the joints

stiffen in a deformed position.

Cortisone and other medications are used in the treatment of arthritis.

Muscle-Bone Disorders Tendonitis

is an inflammation of a tendon, usually at the bone junction.

Usually pain is felt in the wrist or ankle after extensive use such as running or even using a computer.

Other Muscle-Bone Disorders

Scoliosis

Osteoporosis