Chapter 2 locomotion and support

SM Teknik Langkawi, 2011 1

CHAPTER 2SUPPORT AND LOCOMOTION

SM Teknik Langkawi, 2011

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2.1 UNDERSTANDING SUPPORT AND

LOCOMOTION IN HUMANS AND

ANIMALS


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The necessity for support and locomotion in humans and animals Locomotion the ability of animals to

move from place to place Humans and animals need to move

because:- to search for food- To seek shelter- To avoid or escape from predators and other

dangers- To search for a mate to propagate the

species


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Skeleton

Inner framework is made up of bones that are joined together at the joints to form skeleton

There are 5 major functions of skeleton:

1. Provides shape and support2. Enables movement3. Protects internal organs4. Produce blood cells5. Stores materials (ex: calcium &

phosphate)


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Types of skeleton

There are 3 types of skeleton: EXOSKELETON, ENDOSKELETON, HYDROSTATIC SKELETON

1. Exoskeleton- outer covering which is made up of rigid &

strong materials such as calcium or chitin- The jointed external skeleton provides

locomotion and support to insects- For molluscs(snail,oysters)their skeleton

consist of a hard SHELL of calcium, cover and protect the soft body


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2. Endoskeleton- Is an internal skeleton comprising of

many component parts of cartilage or bones

- It protects internal organs from injury- It maintains body shape, supporting soft

tissues, produce blood cells and stores calcium and phosphorus


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3. Hydrostatic skeleton internal watery fluids held under

pressure contained within confined spaces in the body surrounded by the muscles.

Provides support and locomotion to animals such as earthworms and caterpillars


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Human skeleton

Consists of many bones joined together at the joint.

Can be divided into two parts:(A) Axial Skeleton(B) Appendicular Skeleton


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A. Axial Skeleton

Consists of following components:(a) Skull(b) Vertebral column(c) Rib cage


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1. Skull

Consists of the cranium and the facial skeleton

The cranium:- dome-shaped- Formed from the fusion of sutures

(immovable joints which securely hold bones)

- Protects the brain, supports organs of special senses


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Facial bones consists of:- 2 eye sockets (protect the eyeballs)- 2 nasal bones- Upper jaw bone (maxilla) which is fused

to the base of the cranium- Lower jaw bone (mandible) which is

hinged to the cranium movable and allows the mouth to open and close while talking and eating


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2. Vertebral Column

Consists of 33 small vertebral bones/vertebrae Is known as the backbone or the spine Provides protection for the spinal cord Has processes (projection from a bone) for the

attachment of muscles Each vertebra differs in structures depending on its

function and position Intervertebral cartilage disc:- Separates adjacent vertebrae- Acts as a shock-absorbing cushion, reduces friction

& allows movement between adjacent vertebrae


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The 33 vertebrae are made up of:- 7 cervical (cervix=neck) vertebrae in the

neck region- 12 thoracic vertebrae in the thorax

region- 5 lumbar vertebrae supporting the lower

back- 5 sacral vertebrae fused to form a single

sacrum- 4 caudal vertebrae fused to form a single

coccyx


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The typical vertebra

Although vertebrae in different regions vary in size, shape and details, they share certain common physical characteristics

The typical vertebra has these structures:

1) A centrum (body)2) A neural arch (vertebral arc)3) A neural canal (vertebral canal)4) Transverse processes


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/ Neural canal


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1) Centrum- Is a solid piece of bone that can resist compression2) Neural arch (vertebral arc)- Arises from centrum- Neural arc & centrum surround the neural canal- Protects the spinal cord3) Neural canal (vertebral canal)- Is the large hole in the centre of the vertebra- It is continuous with the neural canals of other

vertebrae- Carries the spinal cord


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4. Transverse processes- Are the bony projections for the

attachment of ligaments and muscle tendons

- A short spine called the neural spine projects out from the midpoint of the neural arch


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Cervical vertebrae

There are 3 types:(a) The atlas – the first cervical vertebra(b) The axis – the 2nd cervical vertebra(c) The typical cervical vertebra Atlas and axis allow the head to nod and turn All cervical vertebrae have:- 1 neural canal (the spinal cord passes trough

this hole)- 2 vertebrarterial canals (the vertebral arteries

pass through these holes)


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Atlas

1st cervical vertebra Supports the head Is a ring-shaped bone with large superior

facet which articulate with the base of the skull (at the occipital condyles) to allow for rocking movements

Its neural canal is very large Does not have centrum, transverse

processes and neural spine


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Axis

2nd cervical vertebra Has a centrum and transverse processes Its centrum extends upwards to form a

tooth-like process, called odontoid process

The odontoid process fits into the lower part of the neural canal of the atlas

It allows atlas to turn about the odontoid process


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Thoracic Vertebrae

A typical thoracic vertebra has:- A heart-shaped centrum (body)- A small circular neural canal- A long neural spine which point

downwards- 2 long transverse processes- Facets on both sides of the centrum and

at the end of transverse processes


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Lumbar vertebrae

Kidney-shaped, LARGEST vertebrae in human backbone

Support upper body Have a triangular spinal canal Have large broad transverse processes

and a short broad neural spine Have large superior facets


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Sacrum

Is a triangular bone formed by the fusion of five sacral vertebrae

Four transverse lines indicates the fusion of the vertebrae

On both sides of the transverse lines are paired sacral foramina (openings)


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Coccyx

Is a triangular bone formed by the fusion of four caudal vertebrae

Fused to the sacrum Has no special function

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3. Rib cage

There are 12 pairs of ribs and all articulate with the thoracic vertebrae of the backbone

Among these 12 pairs:a) 7 upper pairs directly join the sternum

by cartilage at the end of the ribsb) Next 3 ribs(8th, 9th and 10th = false rib)

attach to the rib above by cartilagec) The other 2 ribs (floating ribs) are not

connected to the sternum of the rib cage above



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Functions of rib cage:1. To protect vital organs such as the

lungs and the heart2. For the attachment of the intercostal

muscle3. Provides the pumping mechanism

required for breathing


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B. Appendicular skeleton

Components of appendicular skeleton are:

1. The pectoral girdle2. The pelvic girdle3. The upper limbs4. The lower limbs


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1. The pectoral girdle

Contains 2 bones:- The clavicle or collar bone- The scapula or shoulder blade1. The clavicle- Is a long, slender bone that is positioned

horizontally above the first rib2. Scapula- Large, flat, triangular bone situated in

the posterior of the thorax


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2. Pelvic girdle

Consists of two hip bones Provides a strong and stable support for

the vertebral column The hip bones are joined to each other at

a joint called the pubic symphysis


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3. Upper limb

Consists of humerus, ulna, radius, carpus, metacarpus, and phalanges.

Humerus- is the longest and largest bone in the

upper limb.- It articulates with the scapula at the

shoulder and with the ulna and the radius at the elbow


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The carpus(wrist) consists of 8 small bones called carpals

Metacarpus(palm) contains 5 bones called metacarpals

The phalanges are the bone of the fingers

- 14bones, 2 in the thumb, other four fingers have 3 phalanges


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Lower limb

Consists of femur, patella, tibia, fibula, tarsal and metatarsal

Femur is the longest, heaviest and strongest bone in the body

Patella – kneecap which protects the knee joint Tibia- bears the weight of the body Fibula – parallel to tibia and much more

smaller Tarsal- ankle of the foot consists of 6 bones Metatarsals – 5 bones


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Chapter 2 locomotion and support

Health & Medicine

Transcript of Chapter 2 locomotion and support