The human skeleton
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Transcript of The human skeleton
The human skeleton
Axial Skeleton
Includes:
1. Skull
2. Vertebral column
3. Ribs
4. Sternum
Appendicular skeletonIncludes:
1. Girdles – Pectoral and Pelvic
2. Limb Bones – Fore limb and
Hind limb
https://askabiologist.asu.edu/sites/default/files/SkeletonViewer/SkeletonViewer.swf
The SkullCranium:
Consists of 8 flat bones joined together by immovable joints called sutures.
Surrounds and protects the brain.
The bones of the cranium: Frontal Bone (1)
2. Parietal Bones (2)
– the “back” of the head
3. Occipital Bone (1)
4. Temporal Bones (2)
Sphenoid Bone (1)
Ethmoid Bone (1)
There is a large opening at the base of the skull called
the FORAMEN MAGNUM through which the spinal
cord passes
On either side of the foramen magnum is a projection or
condyle which articulate with the first vertebra (called the
ATLAS) to give the nodding movement of the head
Facial bones:
15 facial bones.
Irregular bones that include: cheek nasal , temple and
upper and lower jaw bones.
The only movable bone is the lower jaw.
Mandible- Lower Jaw
The upper and lower jaws bear the sockets for the
32 permanent teeth.
The human dental formula is: 2.1.2.3
The vertebrate column The vertebral columns is divided into 5 regions:
Cervical (neck) region
Thoracic region (chest)
Lumbar region (lower back)
Sacral region
Coccyx
Cervical (neck) region
Consisting of 7 vertebrae.
1st vertebra Atlas
2nd vertebra Axis
Thoracic region (chest)
12 vertebrae each of which bears a pair of ribs
Lumbar region (lower back)
The largest vertebrae as they carry the weight of the body
Sacral region
Consist of 5 fused vertebrae forming a bone called the sacrum.
Coccyx
Made up of 4 infused bones
Curves of a spineFour curves:
The cervical and lumbar regions curving FOWARD
The thoracic and sacral regions curve BACKWARD
FUNCTIONS OF VERTEBRAL COLUMN
Supports the skull
Surrounds and protects the spinal cord.
Provides attachment for ribs, girdles, and back muscles
Separate vertebrae and S-shaped curvature provide flexibility
allowing humans to bend backwards, forwards and sideways.
Cartilage discs act as shock absorbers
RIB CAGE Consists of 12 thoracic vertebrae, 12 pairs of ribs and the
sternum or breastbone
Functions of rib cage:
Protection of the heart and lungs
With the help of the diaphragm and the intercostal
muscles they increase. And decrease the volume of the
thoracic cavity thereby allowing inhalation and exhalation
to take place.