3.5.3 Responses in the Human
[C] Musculoskeletal System
Objectives – What you will need to
know from this section
 Describe the structure & function of the musculoskeletal
system.
 Name components of axial skeleton -- skull / vertebra /
ribs / sternum
 State the position & function of discs in vertebrae.
 State the components of the appendicular skeleton –
pectoral / pelvic girdle & limbs
 Outline the macroscopic anatomy of a long bone
including:
medullary cavity, compact bone, spongy bone and
cartilage.
 State the function of the following: cartilage / compact bone /
spongy bone -- including red & yellow marrows.
 Classify, locate & state the function of joint types -Immovable, slightly free-moving, and synovial.
 Outline disorders from: arthritis/osteoporosis, include the
Causes / Prevention and Treatment
 Outline the role of cartilage & ligaments.
 Outline the role of tendons.
 Outline the general relation of muscle to skeleton.
 State an example of an antagonistic pair of muscles.
Response in the Human
Musculoskeletal System
Skeletons provide
 support,
 protection of
internal organs
 and a rigid frame
for movement.
 The human skeleton has 206
bones, which can be divided
into two parts:
axial and appendicular.
 Axial skeleton – skull, ribs
(12 pairs), sternum
(breastbone) & vertebrae
(backbone).
 Appendicular skeleton –
pectoral and pelvic girdles,
and their attached limbs
(arms and legs)
Axial skeleton
 skull, ribs (12 pairs),
 sternum (breastbone)
 vertebrae (backbone).
 The spine (vertebral
column, backbone) is
a series of 33 bones
(vertebrae).
OUR SPINE -- VERTEBRAE
LEARNING CHECK
• Give 4 functions of your skeleton.
• Name the 2 main parts our skeleton is
divided into.
• The axial skeleton is composed of which
bones?
• The appendicular skeleton is composed of
which bones?
• What is a vertebra?
• Name the sections of your spine.
Appendicular skeleton 1
 pectoral girdle
 attached limb (arm)
Appendicular skeleton 2
 pelvic girdle
 attached limb (leg)
Appendicular skeleton
LEARNING CHECK
• What is your pectoral girdle?
• What is your pelvic girdle?
• What is the difference between the
metacarpals and the carpals?
• What is the difference between the
metatarsals and the tarsals?
• Where are these bones :
Ulna / humerus / femur / patella /clavicle ?
BONE STRUCTURE
 A long bone contains a hollow
centre region called the
medullary cavity, containing
yellow bone marrow that
stores fat.
 The periosteum is a tough
fibrous layer surrounding
each bone.
 Cartilage covers the tips of bones
in joints, reducing friction, and
acting as a shock absorber.
 Compact bone consists of living cells (osteocytes)
embedded in a matrix of calcium salts and a protein
called collagen.
 It is very
dense and
is found
mainly at
the outer
edge of
bones.
 Spongy bone consists of a network
of thin, bony columns and plates,
along with spaces filled with
marrow [red or yellow].
 It gives moderate strength to
bones but makes them lighter.
 Red marrow makes blood cells
(red, white and platelets).
LEARNING CHECK
• What is the hollow centre of a long bone
called?
• Distinguish between compact and spongy
bone
• Distinguish between red and yellow marrow
• What is an osteocyte?
• Why are the tips of bones covered in
cartilage?
JOINTS
 A joint is where the two bones meet.
 Ligaments hold the bones
together at joints.
 There are three main types of joint:
immovable, partially movable and movable.
TYPES OF JOINT
TYPES OF JOINT
 Immovable joint—
bones are fused, e.g.
skull, pelvis.
 Partially movable joint—
bones slide over each
other, e.g. wrist, ankle,
spine.
TYPES OF JOINT
 Free moving (synovial) joint—Ball-and-socket and Hinge.
 Synovial fluid lubricates a joint and acts as a cushion.
 Ball-and-socket joint
– allows movement
in most directions,
e.g. hip, shoulder.
 Hinge joint
– allows movement in
one plane only, e.g.
elbow, knee, finger, toe.
Ball-and-socket joint – Shoulder.
Hinge joint – Knee.
Bones of the Hand
and Wrist.
LEARNING CHECK
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•
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•
•
What is a joint?
What holds your bones together?
Name the 3 main types of joint.
Give an example of a fused joint.
Give an example of a partially movable joint
What is a synovial joint?
Distinguish between a ball-and-socket joint
and a hinge joint.
MUSCLES
 Muscles pull on bones and so provide movement.
 Muscles are attached to a bone by tendons.
 Muscles can only pull
[when they contract]
 they cannot push.
 Muscles can only pull
[when they contract],
they cannot push.
 For this reason, they
are always arranged
in pairs (called
antagonistic pairs)
that operate in
different directions,
 e.g the biceps and
triceps, which control
arm movement.
Bones and muscles of the arm
humerus
biceps
ulna
radius
How would YOU raise the arm?
humerus
biceps
ulna
radius
Were you right?
triceps
relaxes
bone pulled upward
How would you lower the arm?
biceps
humerus
radius
ulna
triceps
Were you right?
biceps relaxes
bone pulled downward
Watch the muscles….
Watch the muscles….
Watch the muscles….
LEARNING CHECK
• Explain the terms “contract” and “relax” as
applied to muscles.
• Why are muscles arranged in antagonistic
pairs?
• Name the pair of muscles that move the
lower arm.
• Distinguish between tendon and ligament
Arthritis – A Bone Disorder
 Arthritis is a painful disorder where there is inflammation in
one or more joints, resulting in swelling, warmth, pain and
restricted movement.
Possible Causes
 Many diseases can be a cause of arthritis, e.g. gout, TB and
infections of the synovial membranes
 Cartilage can degenerate through wear and tear, and old
age.
Prevention
 could be through good diet,
 care in selection of footwear,
 not putting the bones and joints under excessive stress
during exercise.
Treatment
 can be with aspirin to reduce the swelling and pain,
 in severe cases, replacement with an artificial joint [e.g. the
head of the femur in a hip joint].
LEARNING CHECK
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Arthritis is a bone disorder.
What are its symptoms?
What are its possible causes?
What treatment is used for it?
What might be done to lessen the chances
of it?