locomotion and support

The Skeleton SystemWhat would happen if humans didn't have bones? You'd be floppy like a

beanbag. Could you stand up? Forget it. Could you walk? No way. Without bones you'd be just a puddle of skin

and guts on the floor.

The human skeleton consists of 206 bones. We are actually born with more bones (about 300), but many fuse together as a child grows up. These bones support your body and allow you to move. Bones contain a lot of calcium (an element found in milk, broccoli, and other foods). Bones manufacture blood cells and store important minerals.

The longest bone in our bodies is the femur (thigh bone). The smallest bone is the stirrup bone inside the ear. Each hand has 26 bones in it. Your nose and ears are not made of bone; they are made of cartilage, a flexible substance that is not as hard as bone.

Joints: Bones are connected to other bones at joints. There are many different types of joints, including: fixed joints (such as in the skull, which consists of many bones), hinged joints (such as in the fingers and toes), and ball-and-socket joints (such as the shoulders and hips).

Differences in males and females: Males and females have slightly different skeletons, including a different elbow angle. Males have slightly thicker and longer legs and arms; females have a wider pelvis and a larger space within the pelvis, through which babies travel when they are born.

LOCOMOTION AND SUPPORT

Human and animals need to move from one place to anotherto:1. Find food2. Shelter3. Mates4. Avoid predators/dangers

The ability to move in particular direction in its environment iscalled locomotion

To allow movement and locomotion , animals need supportSystem. Support in human and animals is provided by aFramework called a skeleton.

The skeletel System is composed of Bones and cartilages. The function of Skeletal system are:

1. It support and gives a definite shape of the body.2. It acts as a lever system , allowing movement to take place.3. It protect delicate organs: i. The cranium protect brain ii. The vertebral column protect the spinal cord iii. The rib cage protects the heart and the lungs 4. The bone marrow produces blood cells5. It stores calcium and phosphorous in the form of calcium phosphate

The Skeleton is divided into two main parts:

1. The Axial skeleton – The skull - The vertebral column - The sternum and the ribs

2. The Appendicular skeleton- The pectoral girdle - The pelvic girdle

The skull : 22 bonesThe cranial bones-protect the Brain .The facial bones –support the entranceOf digestive system and resporatory system.Suture is the immovable joints that held the skull together

Axial skeleton – THE SKULL

Axial Skeleton- STERNUM AND RIBS

Thoracic cage – consists of12 pairs of ribs and a Sternum(breastbone)

-encloses and protect theOrgan in the thoracic cavityAnd upper abdominal Cavity.

Rib

sternum

vertebra

A pair of ribs articulates with each vertebra.The tuberculum articulates with the facet on the tranverse process and the capitulum articulates with the capitular facet.

The vertebral column or backbone/spine.Composed of a series of bones calledvertebrae.

7 cervical vertebrae, 12 thoracic vertebrae,5 lumbar vertebrae, 5 sacral vertebrae and 4 caudal vertebrae.

*Functions: Permit movement of the vertebral column and absorbvertical shock

VertebraeIntervertebral disc*

Axial skeleton- VERTEBRAL COLUMN

The ATLAS – the first cervical vertebra ( centrum is absent,neural spine is short, the tranverse process is long, broad andflat and the present of vertebrarterial canal

(This attachment allows the noddingMovement of the head.

The AXIS – the second cervical vertebra (The tranverse process are small, the neural spine is large. The centrum is small and projects upwards to form the odontoid process which articulateswith the atlas . This allows the head to move from side to side

Pivot joints allow rotation of one bone on another .Example : The joint between the atlas and the axis

A typical Cervical Vertebra

The thoracic Vertebra – has a long, thick neural spine. The centrum is short and thick. It has a facets for articulate with ribs

The LUMBAR vertebra are larger and stronger than the other vertebrae. They give support to the abdomen and provide forattachment of the back muscles.

The appendicular skeletonconsist of pectoral girdle ,humerus ,ulna , radius , pelvicgirdle , femur , tibia and fibula.

clavicle

scapula

humerus

radius

Ulna

carpusmetacarpus

phalanges

The PELVIC GIRDLE consists of 2 hip bonesthat provide strong and stable support forthe vertebral column.The hips bones are joined to each other at a joint calledpubic symphysis.

coccyx

Obturator foramen

femur

Patella

tibiafibula

tarsus

metatarsus

phalanges

Trabeculae of spongy bone containred marrow

THE STRUCTURE OF A JOINT

A JOINT is a place where two or more bones meet.

The bones are held together by though and elastic fibres called LIGAMENTS

Ligaments allow movement of the bones at the joint preventdislocation of the joint during movement

Synovial membrane secretes synovial fluid into the synovial cavity

Synovial fluid acts as a lubricant to reduces friction between the end of the bones.

Cartilage that cover the end surfaces of the bone , cushions the joints,absorbs shocks and reduces friction . It also protects the bonesfrom wearing away.

A typical synovial joint

Allows movement of bone in one plane i.e . In either of two opposingdirection. - elbows, finger bones , toe bones

Gliding joints( sliding or plane joints )

The most flexible joints. The moveable bone has a rounded end whichfits into sockets in a fixed bone. The moveable bone can swivel , ormove in many direction.

The face contains 12skeletal musclewhich are attachedto the skin. Any movement by thesemuscles causeschanges in facialexpression.

When the biceps contracts, the tendons transmit the pulling force produced bythe contraction to the forearm. At the same time the triceps relaxes,As a result , the elbow joint flexes or bends and the forearm moves upwards. When the triceps contracts and the biceps relaxes , the forearm extends or straightens

A Grasshopper

The flexor muscle in the upper part of agrasshopper’s leg contracts , the lowerleg is pulled towards the body. This is sitting position and the hind leg is foldedin Z shape

A grasshopper uses three legs to support the body to the ground, while the other three legs move together to make successive steps while walking.

Hydrostatic skeleton in earthworm

When circular muscle contract , the longitudinal muscle relax and the animalBecomes thinner and longer . During locomotion , the circular and longitudinal Muscles contract rhythmically to produce peristaltic waves along the body.

Movements in an earthworm

The arrangement of muscles and bones of a birds

The Functions of the fins

SUPPORT IN AQUATIC PLANTS

- natural bouyancy of the water- the stem have plenty of air sacs to keep them light and reduce their density. The tissues are spongy and with large air space known as aerenchyma tissues.

Cross section of stem to show the air sacs of aerenchyma tissue

Water hyacinth

Cross section of stem of water hyacinth

Floating plants – have broad leaves , firm but flexible. enough to resisttearing by wave action . Stem and leaves have aerenchyma tissues.

Submerged plants – Hydrilla sp. Have thin , narrow and flexible leaves to provide little resistance – the plant can betugged at and pulled by water currents without being damaged. No woody tissue.

Hydrilla sp

Support in terrestrial plants

-woody plants – cellulose wall tissue which have deposits of lignin for added strength.Eg: schlerenchyma tissue , xylem vessels and tracheidsButtress roots

-non-woody plants such as herbaceous plant and climbersdepend on the turgidity of their cells and other supportivetissues for give support.

Parenchyma tissues – store starch , sugar and waterCollenchyma tissues – thickened cellulose wall.

Gloriosa sp

Cross section of woody terrestrial plants

Xylem vessels with different types of thickening by lignin.

pitted spiral annular

Summary

Aquatic plants are supported by the :

Buoyancy of waterAerenchyma tissuesAir sacs on the stems

Woody plants are supported by the:

XylemTracheidsSclerenchyma tissuesButtress root

Herbaceous plants are supported by the :

Turgidity of cellsCollenchyma tissues ,parenchyma tissues