The document discusses the skeletal system and its role in support and locomotion. It describes the three main types of skeletons - exoskeleton, endoskeleton, and hydrostatic skeleton. It then focuses on the human skeleton, dividing it into the axial skeleton (skull, vertebral column, rib cage) and appendicular skeleton (pectoral girdle, pelvic girdle, upper and lower limbs). Each component is described in detail, including its bones and functions in providing structure, movement, and organ protection.
3. The necessity for support and
locomotion in humans and animals
Locomotion the ability of animals to move
from place to place
Humans and animals need to move because:
- to search for food
- To seek shelter
- To avoid or escape from predators and other
dangers
- To search for a mate to propagate the species
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4. Skeleton
Inner framework is made up of bones that are
joined together at the joints to form skeleton
There are 5 major functions of skeleton:
1. Provides shape and support
2. Enables movement
3. Protects internal organs
4. Produce blood cells
5. Stores materials (ex: calcium & phosphate)
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6. Types of skeleton
There are 3 types of skeleton:
EXOSKELETON, ENDOSKELETON,
HYDROSTATIC SKELETON
1. Exoskeleton
- outer covering which is made up of rigid &
strong materials such as calcium or chitin
- The jointed external skeleton provides
locomotion and support to insects
- For molluscs(snail,oysters)their skeleton
consist of a hard SHELL of calcium, cover
and protect the soft body
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7. 2. Endoskeleton
- Is an internal skeleton comprising of many
component parts of cartilage or bones
- It protects internal organs from injury
- It maintains body shape, supporting soft
tissues, produce blood cells and stores
calcium and phosphorus
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8. 3. Hydrostatic skeleton
internal watery fluids held under pressure
contained within confined spaces in the body
surrounded by the muscles.
Provides support and locomotion to animals
such as earthworms and caterpillars
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9. Human skeleton
Consists of many bones joined together at the
joint.
Can be divided into two parts:
(A) Axial Skeleton
(B) Appendicular Skeleton
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10. A. Axial Skeleton
Consists of following components:
(a) Skull
(b) Vertebral column
(c) Rib cage
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11. 1. Skull
Consists of the cranium and the facial
skeleton
The cranium:
- dome-shaped
- Formed from the fusion of sutures (immovable
joints which securely hold bones)
- Protects the brain, supports organs of special
senses
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12. Facial bones consists of:
- 2 eye sockets (protect the eyeballs)
- 2 nasal bones
- Upper jaw bone (maxilla) which is fused to the
base of the cranium
- Lower jaw bone (mandible) which is hinged to
the cranium movable and allows the mouth
to open and close while talking and eating
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14. 2. Vertebral Column
Consists of 33 small vertebral bones/vertebrae
Is known as the backbone or the spine
Provides protection for the spinal cord
Has processes (projection from a bone) for the
attachment of muscles
Each vertebra differs in structures depending on
its function and position
Intervertebral cartilage disc:
- Separates adjacent vertebrae
- Acts as a shock-absorbing cushion, reduces
friction & allows movement between adjacent
vertebrae
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15. The 33 vertebrae are made up of:
- 7 cervical (cervix=neck) vertebrae in the neck
region
- 12 thoracic vertebrae in the thorax region
- 5 lumbar vertebrae supporting the lower back
- 5 sacral vertebrae fused to form a single
sacrum
- 4 caudal vertebrae fused to form a single
coccyx
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17. The typical vertebra
Although vertebrae in different regions vary in
size, shape and details, they share certain
common physical characteristics
The typical vertebra has these structures:
1) A centrum (body)
2) A neural arch (vertebral arc)
3) A neural canal (vertebral canal)
4) Transverse processes
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19. 1) Centrum
- Is a solid piece of bone that can resist compression
2) Neural arch (vertebral arc)
- Arises from centrum
- Neural arc & centrum surround the neural canal
- Protects the spinal cord
3) Neural canal (vertebral canal)
- Is the large hole in the centre of the vertebra
- It is continuous with the neural canals of other
vertebrae
- Carries the spinal cord
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20. 4. Transverse processes
- Are the bony projections for the attachment of
ligaments and muscle tendons
- A short spine called the neural spine projects
out from the midpoint of the neural arch
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21. Cervical vertebrae
There are 3 types:
(a) The atlas – the first cervical vertebra
(b) The axis – the 2nd cervical vertebra
(c) The typical cervical vertebra
Atlas and axis allow the head to nod and turn
All cervical vertebrae have:
- 1 neural canal (the spinal cord passes trough
this hole)
- 2 vertebrarterial canals (the vertebral arteries
pass through these holes)
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22. Atlas
1st cervical vertebra
Supports the head
Is a ring-shaped bone with large superior facet
which articulate with the base of the skull (at
the occipital condyles) to allow for rocking
movements
Its neural canal is very large
Does not have centrum, transverse processes
and neural spine
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24. Axis
2nd cervical vertebra
Has a centrum and transverse processes
Its centrum extends upwards to form a tooth-
like process, called odontoid process
The odontoid process fits into the lower part of
the neural canal of the atlas
It allows atlas to turn about the odontoid
process
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25. Thoracic Vertebrae
A typical thoracic vertebra has:
- A heart-shaped centrum (body)
- A small circular neural canal
- A long neural spine which point downwards
- 2 long transverse processes
- Facets on both sides of the centrum and at the
end of transverse processes
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27. Lumbar vertebrae
Kidney-shaped, LARGEST vertebrae in
human backbone
Support upper body
Have a triangular spinal canal
Have large broad transverse processes and a
short broad neural spine
Have large superior facets
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29. Sacrum
Is a triangular bone formed by the fusion of
five sacral vertebrae
Four transverse lines indicates the fusion of
the vertebrae
On both sides of the transverse lines are
paired sacral foramina (openings)
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31. Coccyx
Is a triangular bone formed by the fusion of
four caudal vertebrae
Fused to the sacrum
Has no special function
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32. 3. Rib cage
There are 12 pairs of ribs and all articulate
with the thoracic vertebrae of the backbone
Among these 12 pairs:
a) 7 upper pairs directly join the sternum by
cartilage at the end of the ribs
b) Next 3 ribs(8th, 9th and 10th = false rib) attach
to the rib above by cartilage
c) The other 2 ribs (floating ribs) are not
connected to the sternum of the rib cage
above
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Functions of rib cage:
1. To protect vital organs such as the lungs and
the heart
2. For the attachment of the intercostal muscle
3. Provides the pumping mechanism required
for breathing
35. B. Appendicular skeleton
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Components of appendicular skeleton are:
1. The pectoral girdle
2. The pelvic girdle
3. The upper limbs
4. The lower limbs
36. 1. The pectoral girdle
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Contains 2 bones:
- The clavicle or collar bone
- The scapula or shoulder blade
1. The clavicle
- Is a long, slender bone that is positioned
horizontally above the first rib
2. Scapula
- Large, flat, triangular bone situated in the
posterior of the thorax
38. 2. Pelvic girdle
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Consists of two hip bones
Provides a strong and stable support for the
vertebral column
The hip bones are joined to each other at a
joint called the pubic symphysis
40. 3. Upper limb
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Consists of humerus, ulna, radius, carpus,
metacarpus, and phalanges.
Humerus
- is the longest and largest bone in the upper
limb.
- It articulates with the scapula at the shoulder
and with the ulna and the radius at the elbow
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The carpus(wrist) consists of 8 small bones
called carpals
Metacarpus(palm) contains 5 bones called
metacarpals
The phalanges are the bone of the fingers
- 14bones, 2 in the thumb, other four fingers
have 3 phalanges
43. Lower limb
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Consists of femur, patella, tibia, fibula, tarsal
and metatarsal
Femur is the longest, heaviest and strongest
bone in the body
Patella – kneecap which protects the knee
joint
Tibia- bears the weight of the body
Fibula – parallel to tibia and much more
smaller
Tarsal- ankle of the foot consists of 6 bones
Metatarsals – 5 bones