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By: Harene Chandra

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To move, muscles must work in concert with a skeleton.• The skeleton provides a rigid structure to which muscles are attached.

Muscles exert force only during contraction. Moving a body part back & forth requires two muscles attached to the same section of the skeleton.

These two muscles are known as an antagonistic pair, which functions cooperatively. The nervous system coordinates these muscles.

Muscles :o

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The main function of a skeleton

SupportProtectionMovement

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A

hydrostatic skeleton

An

Endoskeleton

An

Exoskeleton

Types of skeletons ::

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Consists of fluid held under pressure in a closed body compartment.

Examples of animals containing a hydrostatic skeleton:

– Cnidarians

– Flatworms

– Nematodes

– Annelids

Hydrostatic skeleton ::

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Movement and form is controlled by using muscles to change the shape of the fluid filled compartment

A Hydra, for example,

elongates by closing its

mouth by using

contractile

cells in its body wall.

This results in the

constriction of its central

gastro-vascular cavity.

By decreasing the

diameter of the cavity,

the cavity is forced to

become longer.

Hydrostatic skeleton ::

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Body structure of a Hydra :?

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Hard, encasement deposited on an animal’s surface; for example, most molluscs (slugs and snails) are enclosed in a calcium carbonate shell secreted by the mantle (sheet like extension of the body wall)

As the animal grows, it enlarges its shell by adding to the outer edge.

Exoskeletons

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For example, crustaceans (like lobsters) harden portions of their exoskeleton by adding calcium salts.

In leg joints, where the cuticle is thin and flexible, cross linking of proteins and inorganic salt decomposition occurs.

With each growth spurt, an arthropod must shed its exoskeleton to produce a larger one, thus they molt.

Exoskeletons

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Functions of Exoskeleton

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Consist of hard, supporting elements, such as bones which is buried within the soft tissue of animals.

Sponges are reinforced by hard, needle like structures of inorganic materials, or by softer fibres made of protein.

Echinoderms have an endoskeleton of hard plates called ossicles beneath their skin.

Ossicles are composed of magnesium carbonate, calcium carbonate crystals and are usually bound together by protein fibres.

Endoskeletons

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Functions of Endoskeleton

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Animal support system

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COMPARISON

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Human support system

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Comparison of the support system in land and aquatic vertebrates

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Comparison of the support system in land and aquatic

vertebrates

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Comparison of the support system in land and aquatic

intervertebrates

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THE END

THANK YOU