SUPPORT AND MOVEMT PART 2

What are the functions of the skeleton?

1. Support - enabling the body to stay upright and keep its shape.

2. Protection - for the internal organs and tissues of the body such as the heart, lungs and brain.

3. Movement - by the muscles that are attached to the bones.

4. Blood cells - formed in the red marrow of bones.

5. Mineral salts - calcium and phosphates form part of bones and are stored in them.

6. Hearing - the ossicles in the middle ear transmit sound waves to the inner ear and enable us to hear.

How many bones are in the human body?

206 bones

What are the two divisions of the human skeleton

axial and appendicular

axail skeleton

forms the long axis of the body and is made up of the bones of the skull the vertebral column and the rib cage and sternum.

appendicular skeleton

made up of the upper and lower limbs and the limb girdles which attach the limbs to the axial skeleton.

What does the axial skeleton include?

1. skull

2. vertebral column (spine or spinal
column)

3. bony thorax (rib cage and sternum).

What does the axial skeleton provide

the central support for the body. It also protects the internal organs such as the brain, spinal cord and the organs in the thorax.

. How is the skull made up?

Most skull bones are flat bones which are immovably joined together. The mandible (lower jaw) is an exception in that it can move.

Are the twos sets of bones in the skull

1. Cranial bones form the cranium (brain
box)

2. Facial bones form the face.

How are the bones of the cranium

The cranium is made up of eight flat bones which form a helmet-shaped structure.

The immovable fibrous joints between the bones are
called sutures and are dove-tailed together.

the curved upper part is self-bracing which allows the bones to be thin and very strong so they can protect the brain.

Sature

Fibrous joints

fontanelles

membrane-filled spaces

What do fontanelles allow

• baby's head to be slightly compressed during birth

• size of the brain to grow rapidly during infancy.

The bones grow gradually and all the fontanelles should be replaced by bone by the age of two years.

Concussion

a condition causing loss of balance, dizziness and vomitting. After a bad knock on the head, a doctor should examine the patient.

What are the functions of the cranium?

1. Protects the fragile brain.

2. Protects the sense organs of smell, sight and hearing.

3. Provides attachment for the muscles of the head.

foramen magnum

A large opening at the base of the skull through which the medulla oblongata connects to the spinal cord.

occipital condyles

These articulate with the first vertebra, the atlas of the vertebral column in such a way that a nodding movement is possible.

Functions of the facial bones

1. Form the structure of the face.

2. Protect the sense organs of smell, sight and taste.

3. Provide openings for the passage of food and air.

4. Provide attachment for the facial muscles which give rise to various expressions.
5. Secure the teeth.

Sinuses

mucous membrane-lined spaces in certain skull bones that are connected to the nasal cavity.

Sinusitis

An inflammation of these membranes, due to an allergic reaction or infection,If the membranes swell enough to block drainage into the nasal cavity, fluid pressure builds up in the sinuses and a sinus headache results

What is the role of the teeth and jaws?

masticate or chew food.

How is the vertebral column made up?

The vertebral column is a strong, flexible chain of 33 small bones, the vertebrae, that runs down the middle of the body from the skull to the coccyx.

The vertebrae are held in place
by ligaments, which allow some movement but prevent dislocation.
The vertebral column

What are the functions of the vertebral column?

1. Supports the head.

2. Encloses and protects the spinal cord.

3. Serves as a point of attachment for the ribs.

4. Allows spinal nerves to pass through openings between the vertebrae.

5. Serves as a point of attachment for the muscles of the back.

6. S-shape absorbs jolts and aids in balancing.

How are Intervertebral discs

occur between vertebrae.

These have a jelly-like centre covered by fibrous cartilage.

The discs act as shock absorbers during walking jumping and running and they also allow the spine to flex and extend and even to bend sideways.

Can the vertebral column bend?

Each joint between consecutive vertebrae allows for a small amount of movement but, as a unit, a far greater degree of movement is allowed. This enables the vertebral column to bend forwards, backwards and sideways as well as rotating.

What does the S-shape of the backbone allow

• strengthen the backbone
• balance the body
• absorb jolts during movement.

What is meant by a slipped disc?

If the backbone is put under a lot of pressure, the outer cartilage of the disc may rupture and the soft inner centre is forced through the surrounding cartilage.

This bulge is what is called a 'slipped disc'. If this presses on the spinal cord or on a spinal nerve, it can be very painful and numbness in the limbs may occur.

If this condition cannot be cured by resting, traction, anti-inflammatories or painkillers, surgery to repair the damage may be necessary.

What causes paralysis?

An injury can crush or dislocate vertebrae, damaging the spinal cord or even causing it to break.

This in turn will damage nerves leading to muscles and other organs of the body

quadriplegic

If the spinal cord is damaged in the neck (cervical) region, the whole body below the neck may be paralysed.

paraplegic

If the spinal cord in the lumbar region is damaged, the legs may be paralysed. As nerve tissue cannot regenerate, these patients may have to spend the rest of their lives being dependent on a wheelchair to get around.

How can back ache be prevented?

Humans were designed to be hunter-gatherers, walking and running for 2 to 4 hours every day.

How is the bony thorax made up?

The term thorax refers to the whole chest. The bony thorax is a framework formed by the sternum in the front (anteriorly), the ribs and the rib cartilage on the sides (laterally), and the thoracic vertebrae at the back (posteriorly).

How are the ribs made up?

There are 12 pairs of ribs which are flat, curved bones, extending from the thoracic vertebra at the back to the sternum in the front

• upper seven pairs, the true ribs, are attached to
the sternum (breast bone) by flexible strips of cartilage.

• next three pairs, called false ribs, are connected to the rib above by cartilage.

• lowest two pairs, called floating ribs are only attached to the vertebral column.


Intercostal muscles (external and internal) occur between the ribs. On contraction of the external intercostal muscles, the ribcage moves upwards and outwards which results
in inhalation (breathing in). Exhalation (breathing out) takes place when these muscles relax.


The internal intercostal muscles contract to force air out of the lungs, e.g. when coughing or sneezing..

Intercostal muscles

muscles between the ribs

What are the functions of the bony thorax?

1. Protects the vital organs of the thoracic cavity -the lungs, heart and major blood vessels.

2. Supports the shoulder girdles and upper limbs (arms).

3. Provides attachment points for muscles of the back, chest and shoulders.

4. Aids in breathing.

The Appendicular Skeleton

The appendicular skeleton is made up of all the bones of the limbs, together with the bony girdles that anchor them to the axial skeleton.

What are the bony girdles

1. The pectoral girdles are quite mobile and attach the upper limbs (arms) to the axial skeleton.

2. The sturdy pelvic girdles are more rigid and secure the lower limbs (legs) to the axial skeleton.

pectoral girdles

quite mobile and attach the upper limbs (arms) to the axial skeleton.

pelvic girdles

more rigid and secure the lower limbs (legs) to the axial skeleton.

Whats the functions of the bony girdles

This part of the skeleton enables us to carry out all the movements we make during our very busy lifestyles - walking, playing sport, popping sweets into our mouths, brushing our hair

How is the pectoral girdle made up?

• clavicle or collar bone is a long, slender S-shaped bone. One end articulates with the sternum and the other end with the acromium of the scapula (see diagram). This is the only attachment of the pectoral girdle to the axial skeleton.

• scapula or shoulder blade is a triangular bone that
is not attached to the axial skeleton but moves over the ribs at the back

What are the functions of the pectoral girdle?

1. Attach the upper limbs to the axial skeleton.

2. Provide attachment points for many of the muscles that move the upper limbs.

Describe the pectoral girdle

They are very light and allow the upper limbs to move more freely than any other part of the body.

How is the upper limb made up?

Thirty separate bones make up each upper limb.

• The upper arm is made up of a typical long bone,
the humerus. The head of the humerus fits into the glenoid cavity of the scapula at the shoulder, forming a ball-and-socket joint.

• The forearm is made up of two parallel long bones, the radius and the ulna.

Both these bones articulate with the humerus to form the elbow joint (hinge joint) and with the carpal bones of the wrist. The ulna and humerus form the major part of the elbow joint, whereas the radius articulates more with the carpal bones to move the hand

Why do the upper limbs move so freely?

Only the clavicle is attached to the axial skeleton. The scapula can move quite freely across the thorax, allowing the arm to move with it.

The socket of the shoulder joint, the glenoid cavity, is shallow, so it does not restrict the movement of the upper limb.

This arrangement is very good for flexibility but is bad for stability. This is why it is so easy to dislocate a shoulder.

Describe the hand

This part of the arm is used for gripping and manipulating.
The hand is made up of 27 bones which are divided into three groups -

the carpals in the wrist, the metacarpals in the palm and
the phalanges in the fingers and thumb.

How is the pelvic girdle made up in children ?

• ilium (the hip bone)

• ischium (the sitting bones)

• pubis (the two bones which join in the front by means of the pubic symphysis. (This is a semi movable cartilaginous joint).

What happens to the pelvic girdle in adults

In adults these bones become fused for strength and are called the coxal bones although they may still be referred to by their individual names.

What forms the bony pelvis

coxal bones, sacrum, coccyx

What forms the hip joint

The hip joint is formed by the head of the femur articulating within a deep, cup-like socket,
the acetabulum, formed at the point of fusion between the three hip bones.

What are the functions of the pelvic girdle?

1. Attaches the lower limbs to the axial
skeleton.

2. Transmits the weight of the upper body to the lower limbs.

3. Supports and protects the organs within the pelvic area.

4. Provides attachment points for the muscles that move the lower limbs.

How is the lower limb made up?

• The femur that makes up the thigh, is the largest, longest, strongest bone in the body.

The hip joint, a ball-and-socket joint,


• The tibia and fibula are two parallel long bones that form the lower part of the leg.

The larger tibia articulates with the femur to form the knee joint and with a large tarsal bone (talus) at the ankle.

The fibula does not form part of the knee joint and merely helps to stabilize the ankle joint.

How is the foot made up?

This part of the leg is used for support, balance and movement.

It is made up of 26 bones which are divided into three groups -

the tarsals make up the ankle, the metatarsals, the body of the foot and the phalanges the toes.

Rickets

a disease that affects the developing skeletal system of children and other young animals, is the result of the body's inability to absorb calcium salts. This is mainly due to a lack of vitamin D which is necessary for the absorption of calcium and phosphorus.

Why are calcium salts important?

Calcium is the mineral needed to build strong, hard bones in children.

Lower levels of calcium in the blood result in these elements being withdrawn from the bones.

This results in the bones becoming soft, weak and therefore unable to support the weight of the body. This causes skeletal deformities.

Where does vitamin D come from?

• Sunlight - Vitamin D may be produced by
the skin when the skin is exposed to sunlight. This is how most vitamin D is produced.

• Food - Vitamin D in food and in supplements of multivitamins is absorbed from the small intestines.

What causes rickets?

• Malnutrition
a major cause of rickets at any time of life. This can lead to a lack of vitamin D and calcium salts in the diet.

• Perpetual lack of sunlight
the skin producing less vitamin D. This may occur in people who must stay indoors, work indoors during the daylight hours, or live in climates where there is very little sunlight.

• The inability to absorb vitamin D.
As vitamin D is a fat-soluble vitamin, disorders that reduce the absorption of fats will decrease the ability to absorb vitamin D into the body.

symptoms of rickets

Vitamin D deficiency begins months before physical signs and symptoms of rickets appear.

• skeletal deformities such as malformed skull, bowed legs, knock knees, abnormal curvature of the spine, pelvic deformities and breastbone projection in the chest (pigeon chest)

• stunted growth

• dental problems - defects in tooth structure, e.g. poor enamel.

How can rickets be treated?

• When rickets is caused by malnutrition foods rich in vitamin D should be eaten. These include foods such as oily fish (salmon, mackerel, and sardines) and egg yolks. Vitamin D supplements can be taken and vegetarians should look for foods that are fortified with vitamin D, such as cereal, bread, milk and yoghurt.

• When rickets is caused by lack of sunlight, it can be treated with sun exposure. Infants under 6 months should not be exposed to direct sunlight.

• If deficiencies in calcium or vitamin D are (replaced) while the child is young, skeletal deformities often diminish or disappear with time.

• For some cases of bowlegs or spinal
deformities, special bracing may be needed to position the child's body correctly as the bones grow.

• More severe skeletal deformities may need surgery.

Does rickets occur in South Africa?

There are so many hours of sunshine in this country, that sufficient vitamin D can be made in the skin from the pro-vitamin ergosterol. Calcium can be obtained from milk or powdered milk, so there are very few, if any, cases of rickets in South Africa

osteomalacia

abnormal softening of bones in adults

What are the main symptoms of osteomalacia?

• Bone pain - dull aching pain in the lower
back, pelvis, legs and feet is experienced.

• Muscle weakness - decreased muscle tone leads to loss of muscle strength, mainly in arms and legs.

• Bone fractures - bones tend to break more easily.

Osteoporosis

A condition in which the body's bones become weak and break easily.

Joint

part of the skeleton where two or more bones meet.

What are the functions of joints?

1. Hold the skeleton together with the help of ligaments and tendons.

2. Give the skeleton mobility so that parts of the body can move.

Because of joint what can we do

we can bend our arms and legs, move our fingers, nod our head and perform all sorts of other movements.

What are the characteristics and functions of ligaments?

Ligaments are made up of connective tissue - mainly collagen and elastic fibres and are therefore strong, flexible and resilient.

At joints, ligaments may form part of the articular capsule that:
• holds bones together but allows the joints to move
• directs bone movement but prevents damaging movement.

The more ligaments a joint has

the stronger it is

Tendon

Connects muscle to bone

Ligaments

Connect bone to bone

How are tendons

They are made up entirely of groups of collagen fibres which form a white fibrous tissue and therefore are strong but inelastic as they contain no elastic fibres. If the tendon was able to stretch, the action of the muscle would be ineffective.

Functions of tendons

- attach muscle to bone

- provide durability

- conserve space

Tendons stabilize joints as they span the

Stationery bone

the origin. This bone is usually closer to the centre of the body's axis (such as the scapula).

movable bone

the insertion. This bone is usually further from the body's axis (such as the humerus).

How are joints classified?

the material binding them or according to their mobility.

What are the type of joints?

fibrous, cartilaginous, synovial

Fibrous joints

held together by fibrous tissue and are immovable, e.g. sutures of the cranium

Cartilaginous joints

held together by cartilage and are partially movable, e.g. joints between vertebrae and the pubic symphysis in the pelvis.

Synovial joints

held together by a double-layered articular
capsule, have a fluid-filled cavity surrounding the bones and
are freely moveable.

All the joints of the limbs, in fact almost all the joints of the body, fall into this class.

What are synovial joints?

ball and socket joints
hinge joints
Pivot joint (axial joint)
Plane joint

Ball-and-socket joint

contains a bony ball that fits inside a cup-shaped socket. It is the most flexible kind of joint as it allows movement in many directions. It is found in the hip joint between the pelvic girdle (coxal bone) and the femur, and in the shoulder joint, between the pectoral girdle (scapula) and the humerus.

Hinge joint

allows the bones to move up and down but not from side to side.

Examples are
the knee, ankle, elbow (rotating hinge) and joints between the phalanges of the hands and feet.

Pivot joint (axial joint)

allows a bone to rotate. An example is the joint between
the atlas and axis vertebrae in the neck.

Plane joint

gliding joint as a flat bone glides or slips over another flat bone. Plane joints occur between the carpal bones in the wrist and the tarsal bones in the ankle.

What is a bunion?

A bunion is an enlarged bursa at the base of the big toe caused by wearing tight or poorly fitting shoes. The joint becomes thickened and bent and often inflamed.

Bursae

flattened sacs, lined with synovial membrane, found between ligaments, muscles or tendons to prevent them rubbing against bone and causing friction.

What is a sprain?

A sprain results from stretched or torn ligaments in a joint.

A joint is built to withstand tough treatment but if forced beyond its normal limits of movement, an injury is caused.

If the sprain is severe, the joint may have to be kept still for several weeks until the ligaments repair themselves.

As ligaments have a very poor blood supply, healing is slow. The lumbar region of the spine, the ankle and the knee are the joints most often sprained.

What is a dislocation?

A dislocation occurs when bones are forced out of their normal position at joints.

When a joint is dislocated the bones are wrenched so hard that they are pushed or pulled out of place.

Ligaments around a joint are often torn during dislocation which is why the injury can be so painful.

Dislocations are common contact sports injuries and may occur in the knee, the joints of the shoulder, fingers and thumbs.

What is arthritis?

Arthritis is a disease that affects the joints that strikes one in every three woman in South Africa. It is a general term that covers over 100 different diseases and disorders that make joints painful, stiff and swollen.

What are the types of athritis

Osteoarthritis
Rheumatoid arthritis
Gouty arthritis or gout

Osteoarthritis

usually occurs after the age of 50 and often in an individual with a family history of arthritis.

The cartilage that cushions the bones in joints softens and wears away.

The bones then rub against one another, causing pain and stiffness. This is the most common form of arthritis. It is non- inflammatory

Rheumatoid arthritis

chronic inflammatory disorder where the synovial membrane becomes thickened and inflamed, producing too much synovial fluid which causes the joint to swell, becoming painful and finally deformed.

It is an auto-immune disease where the body's immune system attacks its own tissues.

Many joints, particularly the small joints of the fingers, feet, wrists and ankles, are affected.

If allowed to progress, the joints may be totally destroyed and the bone ends fuse.

It usually affects people from early middle age onwards and it affects three times as many women as men.

Gouty arthritis or gout

caused by a build up of uric acid in the blood which results in urate crystals being deposited in the soft tissue of joints.

Very often this condition starts in the joint at the base of the big toe and it is extremely painful.

If left untreated, the articulating bone ends fuse and immobilize the joint. Fortunately there are several drugs which cure gout attacks.

What brings about movement

Movement is brought about by the skeletal muscles applying force to the bones and joints when they contract.

What are the main characteristics of skeletal muscle tissue?

• forms the skeletal muscles that are attached to the bony skeleton

• has stripes called striations

• can be controlled voluntarily.

What are the key functions of skeletal muscles?

• bring about movement of the bones at joints when they contract and relax, causing movements such as walking, throwing a ball, holding a pen and breathing.

• maintain posture and keep the body stable when sitting or standing as the muscles are always in a state of slight tension - a condition called muscle tone.

• together with ligaments, help to stabilize joints.

• generate heat when they contract.

How is a myofibril made up?

Each myofibril is made up of parallel filaments
forming a pattern of alternating:

• dark A bands consisting of thick filaments made up of the protein myosin

• light I bands consisting of thin filaments made up of the protein actin.

What is muscular dystrophy?

Muscular dystrophies (MD) are a group of more than 30 genetic diseases that cause progressive weakness and degeneration of the skeletal muscles that control movement.

Some forms of MD are seen in early childhood, while others may not appear until middle age or later.

The disorders differ in the extent of muscle weakness (some forms of MD also affect cardiac muscle), when the disorder begins, how quickly it progresses and how it is inherited.

Duchenne muscular dystrophy,

where the diseased muscle fibres lack a protein called dystrophin.

This protein is essential for keeping the sarcolemma in a healthy state.

The disorder is caused by an inherited, X-linked recessive gene, carried by females but expressed almost exclusively in males.

What are the symptoms of Duchenne muscular dystrophy?

• The affected muscles enlarge due to deposits of fat and connective tissue.

• The muscle fibres of the skeletal muscle degenerate and atrophy, causing frequent falls and difficulty in running or jumping.

• The disorder progresses very quickly and many sufferers are unable to walk by the age of 12 years.

• It progresses from the extremities upward, finally affecting the head and chest muscles, at which stage a respirator is needed to breathe.

• Those affected rarely live beyond their early 20s as they die from respiratory failure.