The Human Skeleton System 9 CMH Physical Education

What is the Human Skeleton The human Skeleton is part of the support system in humans. It is a strong internal framework. It has two major parts: The Axial Skeleton and Appendicular Skeleton.

Division Of The Skeleton System Axial Skeleton This include the ribs, sternum, spine and skull. Appendicular Skeleton Include the upper limb, lower limb, hip and shoulder girdles.

Axial Skeleton Parts Skull Protects our brain, ears and eyes. Consist of 28 bones.

Vertebral column Protects the spinal cord. Supports the upper body. Help us to move in different directions. Also called the back bone. Consist of 33 very small irregular bones called vertebrae. The vertebral column allow an athlete to bend and stretch his or her body when taking part in sports.

Sternum A point of attachment for the ribs. Helps to strengthen our rib cage.

Ribs There are 12 pairs of ribs. Help to protect our heart and lungs.

Appendicular Skeleton Parts Shoulder girdle Consist of two scapulas and two clavicles. Help to give a sport person good flexibility in the arms.

Arms Bones of the arm are radius, ulna and humerus. Eight carpal bones are found in the wrist. Five metacarpal bones found in the hand. Fourteen phalanges are found in each hand.

Hip Girdle Gives the lower abdomen supports. Give the femur a strong point of attachment. Females normally have a wider hip.

Legs Made up of the tibia, fibula and femur. Seven tarsals are found in each foot. 5 metatarsals 14 phalanges are found in each foot.

Functions Of the Skeleton System Protection The skull and the ribcage have a protective function for example. The skull protects the brain and the rib cage protects the lungs and heart. The vertebral column protects the spinal cord.

Support The vertebral column (backbone) and girdles mainly provide support. Vertebral column supports the body and head, while the girdles support the bones in the limbs. Movement/Locomotion Movement is moving a part of the body while locomotion is the movement of the entire body. Skeleton muscles are attached to bones, therefore when the associated muscles contract they cause bones to move.

Production of Blood Cells The red bone marrow inside larger bones produce red blood cells, white blood cells and platelets. Provide a framework This is keeping the body in shape. Storage of minerals Bone tissues store several minerals, including calcium and phosphorus.

Assistance in Breathing The skeletal system assisted when the diaphragm muscles contract and push the diaphragm up and outwards to expand the rib cage. This make more air enter the lungs.

Tissues of the Human Skeleton Bones Bone is a living hard connective tissue. Make up from ground substance called matrix and bone cells. Also contain calcium phosphate and calcium carbonate. Bone is a living tissue. Long bones are not solid.

The outer layer is compact bone. An inner layer of spongy bone and a central marrow cavity. Hence long bones are tubular. Red bone marrow is where red and white blood cells are made. Yellow marrow does not made blood cells but stores fat. The end of bones are covered with cartilage. Tendons attach muscle to bone.

Types of Bones Long Bones The largest bones in our legs fingers and arms. Long bones are used for the main movements of our body. For example swinging the bat to play a cricket stroke.

Short Bones The small bones found at joints in our feet and hands. Short bones are used for fine movements of the human body. For example moving the wrist to play a cricket shot.

Flat Bones The bones of your skull knee, pelvic girdle and shoulder girdle. Flat bones are used to protect the organs of our body. Flat bones allow large muscles to attach to them.

Irregular Bones Irregular bones are found in our face and vertebral column. These bones give the human body shape and support.

The they are elastic to allow movement. Ligaments A form of connective tissue. Join bone to bone at a joint. Has yellow elastin fibres which make them elastic but tough. The they are elastic to allow movement.

Tendons Attach muscles to bone. Made up of white fibrous protein (collagen) in a matrix. This is a tough non-elastic fibre. Tendons must not stretch when muscle contracts to move the bone.

Cartilage This is a flexible connective tissue. Cartilage reduce friction and absorb shock at joints. Found at the ends of bones, nose and the ears.

Muscles They are bundle of fibrous tissue in a human with the ability to contract. This contraction allow movement to take place or maintain body posture. Muscle tissue contains cells, which contract to allow movement.

Types of Muscles Voluntary Muscle Attached to the bones of the skeleton . This is called voluntary muscle because it contracted when you wish it to.

Involuntary Muscle/Smooth Muscle This muscle is under automatic control. You do not consciously control the contraction of involuntary muscle. Examples of this include the smooth circular muscle found in the walls of the intestines, which moves food by peristalsis.

Cardiac Muscle This is an involuntary muscle. It is located in the walls of the heart. Very strong and resistant to fatigue, as it must work constantly throughout life.

How Muscle Contracts It start by the arrival of nerve impulses. Calcium ion is then release into the muscle and then ATP. Muscles are attached to bones so that when they contract they pull. The muscle shortens and gets fatter when contract.

Pull up your lower arm and watch the muscle in your upper arm bulge. When a muscle relaxes it does not do any work. It extends and gets thinner due to the action of another muscle contracting. This other muscle acts in opposition and the pair are said to work antagonistically.

Movement At the Elbow Joint Flexion Two muscles work antagonistically to flex and extend. The biceps muscle on the humerus contract to pull the ulna and radius closer. The triceps relaxes at this time. The biceps is joined to the radius by a single tendon of insertion. At the other end two tendons of origin are joined to the scapula.

The scapula holds firm and the lower arm will pull up. Extension at the elbow joint The triceps at the back of the humerus will contract. This draws the ulna nearer to the scapula and extend the arm. The biceps relaxes at this time. One point of insertion for the triceps is on the ulna.

The triceps has three points of origin. Two on the upper part of the humerus and one on the scapula.

Joint A joint is formed wherever two or more different bones meet. Movement occurs in many different planes and to make this possible the bones must be joined to each other in different ways.

Types of Joints Fixed Joints Synovial Joints/moveable Joints Are formed where bones are not meant to move. The sutures of the skull is made up of several bones which fuse together in the early years of life. This is important so that the skull provides strong protection for the brain.

Features Of A Synovial Joint Freely moveable joints are called synovial joints. All have the same basic structures. The ligaments hold the bone firmly together. The surfaces of the bones are covered in cartilage. The cartilages are very smooth to reduce friction and Absorb shocks.

The synovial membrane produces the synovial fluid. Synovial fluid serves as a lubricant which help to reduce friction.

Kinds of Synovial Joints Ball and Socket Found in the hip and shoulder. Allows movement in all planes/universal movement. The fitting of the humerus into the cavity of the Scapula (shoulder blade) allows you to swing your arm right around.

Hinge Joints Allows movement in one plane only (like a door) approximately 1800 . as at the knee and elbow joint. Thanks to the hinge joint in the knee footballers can easily run and kick a ball in front of them.

Gliding joint These joints allow bones to glide over each other, giving flexibility in the area. Allows several angles of movement. Are found where there are several small bones. Thanks to gliding joints in the hands bowlers are able to hold and spin the ball in cricket, and batsman can grip the bat.

Pivot joint One bone stays stationary while the other rotates on it. Example at the neck and head.

Posture And Locomotion Good posture means that the body is held correctly so that there is only slight tension in the muscles.

Factors that Affect The Skeleton Poor posture puts strain on muscles and they lose their tone. High-heeled shoes can cause bad posture while standing. This strain leg muscles.

Arthritis Inflammation of the joints. This is a deterioration of the cartilage covering the bones in the joints.

Dislocation This happens when a bone is forced out of its normal position in the joint cavity. Fractures This occur when you put more pressure on a bone than it can stand, causing it to crack, split or break. A break of any size is called a fracture.

Osteoporosis This is a condition in which the bone matrix is lost and not replaced, resulting in an increased softening and weakening of the bones. Rickets Is a disease in you children caused by a deficiency vitamin D and calcium, resulting in soft and deformed bone.

Sprains Occur when a ligament is damaged or torn because excessive force is applied to the joints.