CHAPTER 8

SUPPORT AND MOVEMENT

HUMAN SKELETON

Pelvic girdle

8.1 Support system in humans

1. Humans are supported by an endoskeleton.

2. The endoskeleton of humans consists of 206 bones.

3. The spinal column consists 33 small bone (vertebrae).

4. Weight supported by pelvic girdle.

5. The functions of the endoskeleton in humans include:

a) support the weight of the bodyb) Give the body its structure

and shapec) Produce blood cellsd)Protect soft organs of the

body such as the heart and the kidneys.

e) Act as a base for attachment of muscles.

Support system in land vertebrates.

1. Land vertebrates are supported by endoskeleton.

2. The endoskeleton:- give them shape- support their weight- protect their soft tissues and organs of the body

3. The weight supported by pectoral (shoulder) and pelvic (hip) girdles.

The skeleton of an elephant

Support system in aquatic vertebrates

1. The body weight of aquaticvertebrates is supported by the buoyancy of water.

2. Pectoral and pelvic girdle are very weak.

3. Can grow to enormous sizes because they do not support their weight.

SUPPORT SYSTEM IN

LAND INVERTEBRATE

S

Land invertebrates that have no backbone are supported by:

(a)Hard exoskeletons(b)Hydrostatic skeleton (body

fluid)

1. Invertebrates have hard external structures for:a) maintaining their shapeb) supporting their bodyc) protecting their internal body

organsd) aiding movement.

2. Hard external structures are called exoskeletons.3. Contraction and relaxation of pairs of muscles on the internal surfaces of exoskeleton allow movement to occur.4. Exoskeleton consist chitin.5. The exoskeleton of invertebrates is also called cuticle.6. Cuticle coated with layer of wax that make it impermeable to water and gives it a shiny look.