Biology - Musculoskeletal System

Functions of the Skeleton

• support

• protection

• movement

• shape

• manufacture of blood components

Axial Skeleton

consists of the skull, spine, ribs and sternum (breastbone)

Spine

made up of 33 bones called vertebrae

7

number of vertebrae in cervical (neck) region of spine

12

number of vertebrae in thoracic (chest) region of spine

5

number of vertebrae in lumbar (back) region of spine

5

number of vertebrae in sacrum (hip) region of spine

4

number of vertebrae in coccyx (tail) region of spine

True Ribs

the top seven ribs attached to the breastbone

False Ribs

ribs 8,9,10 are attached to each other at the front of the chest by cartilage

Floating Ribs

the bottom two ribs, which are only attached to the spine

Appendicular Skeleton

composed of the limbs (arms and legs), the pectoral (shoulder) girdle, and the pelvic (hip) girdle

Pectoral Girdle

consists of the collarbone (or clavicle) and the shoulder blade (or scapula)

Pelvic Girdle

is composed of two halves of the hip joined to the sacrum

A: humerus

B: ulna

C: radius

D: carpals

name the bones of the arm

A: femur

B: patella

C: tibia

D: fibula

name the bones of the leg

Cartilage

covers the ends of bones, is composed of the protein collagen

Functions of Cartilage

• acts as a shock-absorber

• allows friction-free movement

Epiphysis

head of long bone

Diaphysis

shaft of long bone

Compact Bone

hard and strong

→ gives strength and flexibility to the bone

Spongy Bone

more porous

→ has hollow spaces containing bone marrow

→ makes blood cells

Medullary Cavity

a hollow tube located at the centre of the shaft of a bone

→ contains bone marrow

Osteoblast

a bone-forming cell

Growth Plate

the area between the epiphysis and the diaphysis in a long bone within which bone growth occurs

Ossification

cartilage is formed and turned into bone

→ occurs in the growth plate

Osteoclast

a bone-digesting cell

Joint

where two or more joints meet

Immovable Joints

joints in the skull and pelvic girdle

Slightly Movable Joints

joints between the vertebrae in the upper spinal column

Synovial Joints

include ball and socket, and hinge joints

Synovial Fluid

produced in movable joints to lubricate and reduce friction

Ball and Socket Joints

joints in the shoulder and hip

→ allow movement in all directions

Hinge Joints

joints in the elbow and knee

→ allow movement in one direction only

Ligaments

strong, fibrous, slightly elastic tissues that connect bone to bone

Tendons

strong, flexible, inelastic fibres that connect muscle to bone

Arthritis

• a disorder that results in inflammation of joints

• may be prevented by reducing damage to joints in sports

• treated by rest, exercise, drugs and surgery

Antagonistic Pair

two muscles that have opposite effects to each other

Biceps

is a flexor

→ closes the joint

Triceps

is an extensor

→ opens the joint