The Skeletal System

Front 1

Functions of the skeletal system

Back 1

>Protection

cranium of the skull protects the brain

>support

supports soft body tissues to give shape to our bodies

>movement

provides a solid structure for muscle attachment

>manufacture of blood cells

the marrow of some bones e.g. long bones, produces blood cells

>Calcium store

bones provide a store of calcium

>breathing

the ribcage when moved by the intercostal muscles help to increase and decrease the volume of the thorax which bring about inhalation and exhalation

Front 2

Structure of bone

Back 2

The shaft in a long bone is hollow in the sense that its centre is filled with bone marrow and blood vessels, rather than with hard bone. This makes the bone strong but lightweight.

Front 3

Bone

Back 3

>in bone tissue, the bone secreting cells(osteocytes)secrete a rigid matrix of protein and calcium salts

Front 4

Cartilage

Back 4

>in cartilage tissue the secreting cells(chondrocytes) secrete a flexible matrix of protein

>prevents bone from rubbing on bone

>shock absorber

Front 5

Tendons

Back 5

>have tensile stength(the resistance of a material to breaking under tension)

>little elasticity

>join muscles to bones

>needs to be very strong and non elastic

>composed of a tough protein, collagen

Front 6

Ligaments

Back 6

>hold bone to bone

>have tensile strength

>some elasticity so joints can bend without the bones dislocating

>composed of fibres of an elastic protein, elastin

>elastin gives ligaments strength and elasticity

Front 7

Joints

Back 7

>occur where two bones meet

>also known as bone articulation

>three types;

*fixed joints

*slightly movable

*freely movable

Front 8

immovable joints(fixed)

Back 8

bones of the cranium of the skull

they are fused together

Front 9

Slightly movable

Back 9

joints between the adjacent centra of the vertebral column

Front 10

Synovial joints(freely movable)

Back 10

>can be further classified according to range of movement they allow

>allow friction free movement

>parts are

*cartilage(shock absorber)

*ligament(holds bone to bone)

*synovial membrane(produces synovial fluid)

*synovial fluid(lubricates joint, nourishes cartilage)

Front 11

Hinge joint

Back 11

>allows freedom of movement in one plane

>elbows, knees, fingers

Front 12

Ball and socket joint

Back 12

>allows freedom of movement in any plane

>shoulder, hip

Front 13

Skeletal muscles

Back 13

>made up of many muscle fibres containing contractile proteins

>can contract

>maintains posture

>allows movement

>can be classified according to movement they bring about

Front 14

Rotators

Back 14

bring about rotation of a limb

Front 15

extensors

Back 15

cause a straightening of the limb(increse angle between bone)

Front 16

flexors

Back 16

cause a bending of the limb(decrease angle between bones)

Front 17

Origin muscle

Back 17

attached to a bone that does not move a great deal

Front 18

Insertion muscle

Back 18

attached to a bone that moves a great deal

Front 19

Antagonistic muscles of the arm

Back 19

Antagonistic pairs

When one of the muscles contracts the other one relaxes.

One muscle in the pair contracts to bend the joint

the other muscle in the pair contracts to straighten the joint

biceps-flexors

triceps-extensors

Front 20

Locomotion

Back 20

our skeleton has evolved so that we have a bipedal hebit which allows an upright stance

our hind limbs are used for locomotion

Front 21

Effects of exercise

Back 21

>more capillaries produced in muscles

>muscles become larger

>greater endurance achieved

>muscle tone will increase

>joints will become more flexible

Front 22

Posture

Back 22

Bad posture leads to

>more energy needed by muscles to keep the body upright leading to muscle fatigue and backache

>digestive/breathing system being compressed and working less efficiently

>main blood cells becoming compressed and therefore carrying less blood

Front 23

Footcare

Back 23

ill fitting shoes caues

>bunions

>hammer toe

>corns

>backache