Chapter 12
Human Biology Stage 3
Unit 3B – Body systems
Keywords
 Connective tissue
 Matrix
 Long bone
 Cartilage
 Synovial joints
 Chondrin
 Hinge
 Collagen
 Ball & socket
 Diaphysis
 Hyaline cartilage
 Pivot
 Epiphysis
 Elastic cartilage
 Saddle
 Articulate
 Fibrocartilage
cartilage
 Compact bone
 Haversian
system
 Spongy bone
 Bone marrow
 Joints
 Movement
 Adduction
 Fibrous
 Abduction
 Cartilaginous
 Flexion
 Synovial
 Extension
 Rotation
The skeletal system
 The skeletal system consists
of the bones, joints,
ligaments and cartilage.
 All the components of the
skeletal system are classified
as connective tissue
 The function of the skeletal
system is to:
 Support
 Protect
 Facilitate movement
 Act as storage organs
 Produce blood cells
Bones
Structure of bone
 Bone is made up of a
mineralised matrix and
includes blood vessels, cells,
nerves, collagen and bone
marrow.
 A long bone consists of:
 A shaft, called the diaphysis
 The ends, called the
epiphyses. A thin layer of
articular cartilage cover
each epiphysis
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Bone
There are two types
of bone:
•compact bone,
which is very hard
and dense
•spongy bone,
which is porous and
consists of a
network of small
bony plates.
Compact
bone
Spongy
bone
Medical Art Services, Munich, Wellcome Images
Compact bone
 Compact bone consists of Haversian systems.
 A Haversian system comprises of circular layers of
bone tissue (lamellae) surrounding a central
Haversian canal, which carries blood and lymph
vessels.
 Within the Haversian system are osteocytes. These
are mature bone cells and are contained within spaces
called lacunae
Compact bone
Compact bone
Haversian systems
Haversian
system
Haversian
canal
Concentric
lamellae
Lacuna
with
mature
osteocyte
M I Walker, Wellcome Images
Spongy bone
 Spongy bone is found in the
epiphyses of long bones
 It is more porous than
compact bone
 The spaces in spongy bone
are filled with bone marrow
 In some spongy bone, the
spaces are filled with red
bone marrow. This is where
blood cell production takes
place
Articulating cartilage
Growth cartilage
Spongy or
cancellous bone
Epiphysis
Marrow
cavity
Periosteum
Diaphysis
Compact
or dense bone
The Miles Kelly Art library, Wellcome Images
Cartilage
Cartilage
 Cartilage contains fibres made of protein called collagen.
These fibres are embedded in a matrix of a proteincarbohydrate complex called chondrin
 This firm matrix gives cartilage its strength but still allows
for flexibility
Function
 Support & structure
 eg. ear, nose, trachea
 Protection
 stops joint bones from rubbing against each other
http://www.ivy-rose.co.uk/HumanBody/Tissue/Tissue_Cartilage-Tissue.htm
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Microscopic structure of cartilage
 Within the matrix are
spaces that contain
cartilage cells called
chondroblasts
 The chondroblasts
produce matrix until they
are surrounded and
trapped in small spaces
called lacunae. When this
occurs the cell is
considered mature and
now called a chondrocyte
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Types of cartilage
Type
Characteristics
Example
Hyaline
•Collagen fibres are fine
and closely packed
•End of bones to form
moveable joints
•Rings of trachea & bronchi
Elastic
•Contains elastic fibres.
•Collagen fibres not as
closely packed as in
hyaline.
•External ear
Fibrocartilage
•Contains thick bundles of
collagen fibres which
provide cushioning
•Invertebral discs in spinal
column
•Knee joints
•Pelvis
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Joints
Joints
 The site at which two or more bones come together is
called a joint
 There are many types of joints
 Joints are classified according to their range of
movement, this is called a functional classification.
 Joints may also be classified structurally according to
the connective tissue that binds the bones together.
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Joint classification
 Joints can be classified by their structure and the
amount of movement they allow.
Structure
Joint cavity
Movement
Fibrous
None
None
Cartilaginous
None
None or slight
Synovial
Present
Freely movable
Types of joints
Movable
synovial joint
Wellcome Photo Library
Immovable or fibrous joints
 When no movement
occurs between the
bones concerned, the
joint is described as
immovable.
 The bones are held in
place by fibrous
connective tissue .
 It is very difficult to
damage this type of
joint, as it is so strong.
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Immovable
fibrous joint
Slightly movable or cartilaginous
Slightly movable
joints
cartilaginous joint
 These joints are held in
place by cartilage to allow
slight movement to occur.
Found:
 between the 2 pelvic
bones
 between adjacent
vertebrae
 between the ribs and the
sternum.
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Freely movable or synovial joints
 Most of the joints in the body are freely moveable, the
amount of movement possible being limited my
ligaments, muscles, tendons and adjoining bones.
 These joints are known as synovial joints
 They occur at the shoulder, elbow, wrist, fingers, hip,
knee.
 They have a synovial cavity between the articulating
surfaces of the bone.
 A synovial membrane surrounds the synovial cavity
and there is articular cartilage on the bone surfaces.
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The structure of a synovial joint
Fibrous
capsule
Synovial
membrane
Bursa
Joint cavity
Articulating
cartilage
Wellcome Photo Library
Movement at a joint
 Flexion or bending i.e. bending the knee
 Extension or straightening, usually increases the
angle between the articulating bones i.e. straightening
the arm or leg after flexion.
 Abduction which is a movement away from the body’s
midline
 Adduction is movement towards the body’s midline
 Rotation is the movement of bone around its long
axis i.e. rotation of the humerus.
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Movement at a joint
Type
Flexion
Extension
Abduction
Adduction
Rotation
Explanation
Bending
Straightening
Increases the angle between
the articulating bones
movement away from the
body’s midline
movement towards the
body’s midline
movement of bone around
its long axis
Example
Bending the knee
Straightening the leg
after bending at the
knee
Lifting arm up to the
side
Bringing arm back
down
Rotating the arm rotates the humerus
Synovial joints
Types of synovial joints:
Hinge joint
Ball & socket joint
Pivot joint
Saddle joint
Flexion
Extension
Hinge joint
Abduction
Ball & socket
joint
Pivot joint
Rotation
Adduction
Rotation
Hinge joint
Mariana Ruiz Villarreal
Ball and socket joint
Mariana Ruiz Villarreal
Pivot joint
Mariana Ruiz Villarreal
Saddle joint
Mariana Ruiz Villarreal
Trauma injuries to skeleton
 For the following topics (on the next slide) you need to
answer the research questions:
 What is it?
 How is it caused?
 How can it be treated?
 Can it be cured?
 Can it be prevented?
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Topics
 Spinal injuries
 Broken bones
 Ligament damage
 Arthritis
 Osteoporosis
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