science (support and movement )

7/29/2019 SCIENCE (Support and Movement )

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ENDOSKELETON OR INTERNAL SKELETON

1. The human body is supported by an internal skeleton ofbones called the endoskeleton.

2. An endoskeleton is made of cartilage.

3. Cartilage is a strong flexible material that is found in

our nose and ears.

4. Muscles and other soft tissues are attached to the outside

of the endoskeleton.

5. They form on the outside of most vertebrate bodies of a

soft covering.


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The Human Skeleton

1. The human body is supported by an internal skeleton of

bones called endoskeleton.

2. Besides supporting the body, the skeleton gives the body

shape.

cranium

BackbonePectoral

girdle

Pelvic girdle

Radius

ulna

Femur

tibia

Fibula

humerus

Rib cage

Sternum


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3. The weight of the body is mainly supported by the pelvic

girdles. This is why the pelvic girdles are very solid and

strong.

4. Unlike animals which walk on four limbs, the pectoral

girdlesdo not have to support the body weight.

5. The long bones of the body are generally used for

movement, e.g. the humerus and the femur.

6. Thejoints enable the parts of the body to bend and turn.

7. The cranium protects the brains.

8. The breastbone and ribs enclose and protect the lungs

and the heart.

9. The backbone is a chain of 33 small bones. This makes

the backbone flexible, enabling the body to bend forwardsand backwards.

10. The marrow in the long bones make white blood cells

and red blood cells.


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SUPPORT IN LAND VERTERBRATES

1. Land vertebrates, e.g. the elephant and the horse, havevery strong endoskeleton.

2. The endoskeleton serves the following functions:

* It supports the body weight of the animal

* It maintains the shape of the animal

* It protects the internal organs of the animal


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The Support System In Elephant

Pelvic Girdles

* Support the weightof the body.

Backbone

* Helps to support the body and enables the body to bend.

Backbone

Pectoral girdle

Joints

Rib bones

Pelvic

girdles

Leg bones


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Pectoral Girdles

* Support the weight of the body.

Joints

* The joints enable parts of the body and the long bones to

bend. The hinge joints in the legs can bend in one direction

only.

Leg Bones

* These help the animal to move.

*Each long bone contains a hollow to make the bone light.

* This hollow bone is stronger than a solid bone of the

same length and weight.

Ribs Bones

* The rib bones enclose and protect the lungs and the heart.

SUPPORT IN AQUATIC VERTEBRATES

1. Aquatic vertebrates, e.g. the whale, have endoskeletons.

2. The whale is a huge animal. In fact, the blue whale is the

largest animal in the world.


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3. The whale has a very small and weak endoskeleton for

its weight and size.

4. The whale can live in the sea with such a weakendoskeleton because its body is lifted up (buoyed up) by

the lifting force (upthrust) of the water.

5. * A whale washed ashore cannot move back to the sea

because its endoskeleton cannot support the weight of the

body.

* The weight of the body will crush the endoskeleton and

kill the whale.

The Whale Is Supported By The Lifting Force

(Upthrust) Of The Sea

BackboneEndoskeleton

Pectoral girdlesPelvic girdles


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Endoskeleton

* Gives the whale shape and structure.

Backbone

* Enables the whale to bend its body in the water.

Pelvic Girdles

* Very small and cannot support the weight of the whale on

land.

Pectoral Girdles

* Small and weak compared to the whales weight and size.

Comparison between the support systems in land

vertebrates and aquatic vertebrates.


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1. Invertebrates are animals without backbone.

SIMILARITIESLAND VERTEBRATES(ELEPHANT)

Internal Skeleton

(Endoskeleton)

AQUATIC

VERTEBRATES(WHALE)

DIFFERENCES

Internal skeleton

system

Big

Very strong

Buoyancy of water

Comparatively small

Comparatively weak

Type Of Support

System

Size Of Pectoral

and Pelvic Girdles

Strength Of

Pectoral and

Pelvic Girdles


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2. Some are supported by exoskeletons.

3. Some are supported by hydrostatic skeletons.

EXOSKELETON

1. An exoskeleton is a hard outer layer covering the

invertebrate.

2. The exoskeleton is made of a hard substance called

chitin.

3. The exoskeleton:

* supports the invertebrate

* maintains its shape

* protects its internal parts

4. The exoskeleton is shed when the invertebrate grows.

This process is called moulting.

Examples of invertebrates with exoskeleton


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Cockroach

Scorpion

Prawn


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HYDROSTATIC SKELETON

1. An invertebrate with a soft body has a hydrostatic

skeleton.

2. It consists of a body with fluid in its body cavity. The

fluid in the body cavity exerts pressure outwards and makes

the body stiff (turgid).

3. The hydrostatic skeleton:

* supports the soft body

* maintains the shape of the body

* enables the invertebrate to become firm and move about.

Examples of invertebrates with hydrostatic skeletons

Crab


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Earthworm

Slug

Jellyfish


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Starfish

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