1. Lesson Overview The Skeletal SystemLesson Overview The Skeletal System
•Who won the skeleton beauty contest? • No body
•What do skeletons say before they begin
dining?
•Bone appetit !
Why didn't the skeleton dance at the
Halloween party?
•It had no body to dance with!
•What did the skeleton say while riding
his Harley Davidson motorcycle?
•I'm bone to be wild!
• Who was the most famous French
skeleton?
•Napoleon bone-apart
•What instrument do skeletons play? •Trom-BONE.
•Why couldn't the skeleton cross the
road?
•He didn't have the guts.
•How did the skeleton know it
was going to rain ?
•He could feel it in his
bones !
•How do skeletons call their friends ?
•On the telebone !
•What do you call a skeleton who
won't get up in the mornings ?
•Lazy bones
•Why don't skeletons play music in
church ?
•They have no organs !
• What is a skeleton ?
•Somebody on a diet who forgot
to say "when" ! !
2. Lesson Overview The Skeletal SystemLesson Overview The Skeletal System
EXOSKELETON
ENDOSKELETON
4. Lesson Overview The Skeletal System
What are the functions of the skeletal system?
Support – rigid framework that maintains the shape of the body; supports the
organs suspended within it.
Protection – soft and delicate tissues and organs are protected by the skeleton.
Movement – muscles can attach to the bones.
Production of blood cells – red and white blood cells are made in the bone
marrow.
Storage of minerals (and lipids) – calcium and phosphorus levels are maintained
by storing the excess in the bones.
5. Lesson Overview The Skeletal System
Parts of the skeletal system
Bones (skeleton)
Joints
Cartilages
Ligaments (bone to bone)(tendon=bone to muscle)
6. Lesson Overview The Skeletal System
Structure of the Skeleton
There are 206 bones in the adult human
skeleton.
22 bones in skull
6 in middle ears
1 hyoid bone
26 in vertebral column
25 in thoracic cage
4 in pectoral girdle
60 in upper limbs
60 in lower limbs
2 in pelvic girdle
Divided into axial skeleton and
appendicular skeleton.
7. Lesson Overview The Skeletal System
Structure of the Skeleton
The axial skeleton supports the
central axis of the body and consists
of :
• Skull (cranium and facial bones)
– The cranium has a number of flat bones fitted together
at immovable joints.
• Vertebral column
– The backbone has 33 bones called vertebrae placed end
to end, each separated from the other by a cartilage disc.
• Ribcage and sternum
8. Lesson Overview The Skeletal System
Structure of the Skeleton
The bones of the arms and legs, along with the
bones of the pelvis and shoulder area, form the
appendicular skeleton.
• Arms and legs
– The upper part of the limbs consists of single long bones – the humerus in the
arm, and the femur in the leg.
– The lower part of the limbs has a pair of bones below the elbow or knee – the
radius and ulna in the arms, and the tibia and fibula in the legs.
• Pectoral and pelvic girdles
– The pectoral, or shoulder, girdle, consists of the clavicle (collar bone) and
scapula (shoulder blade). This girdle connects the humerus to the rest of the
skeleton.
– The pelvic girdle consists of two halves. These two hip bones (sacrum,
coccyx) form a hollow cavity known as the pelvis. This girdle connects the
femur to the rest of the skeleton.
9. Lesson Overview The Skeletal System
Bones
• Made of layers of living tissue
• Covered with a tough, tight-fitting
membrane called the periosteum
10. Lesson Overview The Skeletal System
Bones
What is the structure of a typical human bone?
A bone is a solid network of living cells and protein fibers (collagen) that
are surrounded by deposits of calcium and magnesium salts .
which is mostly stored fat.
11. Lesson Overview The Skeletal System
Adults continually break down and
build up bone
Osteoclasts remove damaged cells
and release calcium into blood
Osteoblasts remove calcium from
blood and build a new matrix.
12. Lesson Overview The Skeletal System
Compact Bone
• Directly under the periosteum
• Hard, strong layer
• Gives bones strength
• Contains deposits of calcium phosphate
• Contains bone cells and blood vessels
13. Lesson Overview The Skeletal System
Spongy Bone
• Located at the ends of long bones
• Has many small, open spaces that make
bones lightweight
• Filled with a substance called marrow
– yellow composed of fat cells
– red produces red blood cells
14. Lesson Overview The Skeletal System
Classification of Bones on the Basis
of Shape
*Longer than wide
*Bear weight
*About same length as width
*Bear weight
Thin and usually curved
Protect brain and thoracic
organs
Skeletal System
(e) Sesamoid
(e.g.,Patella)
Small and round
16. Lesson Overview The Skeletal System
Characteristics of cartilage
• Smooth ,glossy ,flexible thick layer of
tissue
• It doesn’t contain very many minerals
although it contains collagen
• Does not contain blood vessels
• Covers the ends of bones
• Spread loads, reduces friction, and
allows flexible movement, acts as a
shock absorber
17. Lesson Overview The Skeletal System
The Vertebral Column
33 Vertebrae separated by
intervertebral discs
The spine has a normal
curvature
Each vertebrae is given a
name according to its
location
The spinal cord runs
through an arch of bone
formed by the vertebrae
19. Lesson Overview The Skeletal System
The Skull or Cranium
•The skull protects the brain, most of the organs of the senses and entrances to
respiratory and digestive systems.
The skull has 28 bones (14 belong to the face) join by immovable joints can’t
move at all.
They either interlock or overlap.
hinged to the skull
20. Lesson Overview The Skeletal System
The Hyoid Bone
The only bone that
does not articulate
with another bone
Serves as a
moveable base for
the tongue
21. Lesson Overview The Skeletal System
Thoracic Cage
Commonly called the rib cage
Protects the heart, lungs, and other organs of
the thoracic cavity
Encloses the thoracic cavity
Composed of twelve pairs of ribs and the
sternum (breast plate or bone)
22. Lesson Overview The Skeletal System
The classification of ribs:
1. True ribs – 1st 7 pairs that attach directly to the sternum by the
coastal cartilage
2. False ribs – inferior 5 pairs that connect indirectly (first 3 pairs)
to the sternum or do not attach at all to the sternum (last two pairs)
3. Floating ribs – the last two pairs of false ribs that are not
attached at all
23. Lesson Overview The Skeletal System
Bones of upper limb
Humerus (upper arm)
Radius; ulna
Carpals, metacarpals, phalanges
Bones of lower limb
Femur
Patella
Tibia, fibula
Tarsals, metatarslas, phalanges
26. Lesson Overview The Skeletal System
How are bones connected together?
• By Ligaments:
A ligament is a tough band of white, fibrous, slightly
elastic tissue. This is an essential part of the skeletal
joints; binding the bone ends together to prevent
dislocation and excessive movement that might cause
breakage. Ligaments also support many internal organs;
including the uterus, the bladder, the liver, and the
diaphragm .
• By Joints: constructed to both allow
movement and provide mechanical
support.
27. Lesson Overview The Skeletal System
• Joints are where two, or more,
bones meet.
• They are divided up into three
types depending on how
freely the bones can move:
Immovable
slightly movable
freely movable
• Joints contain connective
tissues that hold bones
together.
• Joints permit bones to move
without damaging each other.
• If we did not have joints no
movement would occur.
28. Lesson Overview The Skeletal System
• Joints
• Immovable: bones sutured together by
connective tissue: skull
• Slightly movable connected by
fibrocartilage or hyaline cartilage:
vertebrae, rib/sternum joint, pubic
• Freely movable – separated ligaments-
hold bones together
tendons- muscle to bone
lined by synovial membrane
29. Lesson Overview The Skeletal System
Types of Joints
Hinge- A hinge joint allows extension
and retraction of an appendage. (Elbow,
Knee)
30. Lesson Overview The Skeletal System
Ball and Socket- A ball and socket joint
allows for radial movement in almost
any direction. They are found in the hips
and shoulders. (Hip, Shoulder)
31. Lesson Overview The Skeletal System
Gliding- In a gliding or plane joint bones
slide past each other. Mid-carpal and mid-
tarsal joints are gliding joints. (Hands,
Feet)
32. Lesson Overview The Skeletal System
Saddle- This type of joint occurs when the
touching surfaces of two bones have both
concave and convex regions with the
shapes of the two bones complementing
one other and allowing a wide range of
movement. (Thumb)
33. Lesson Overview The Skeletal System
• Pivot: Rounded or conical surfaces of one bone
fit into a ring of one or tendon allowing rotation.
An example is the joint between the axis and
atlas in the neck.
Examples
• The joint between the atlas and
axis.
• The joint between the radius
and ulna.
34. Lesson Overview The Skeletal System
Types of movement and examples (with muscles)
flexion- move lower leg toward upper
extension- straightening the leg
abduction- moving leg away from body
adduction- movong leg toward the body
rotation- around its axis
supination- rotation of arm to palm-up position
pronation- palm down
circumduction- swinging arms in circles
inversion- turning foot so sole is inward
eversion- sole is out
35. Lesson Overview The Skeletal System
Freely moveable joints Or Synovial joints.
• Outer sleeve is called the joint capsule.
– It holds bones together &
protects joint.
– It is an extension of the skin
or periosteum that covers
the bone.
• A synovial membrane.
– Lines the capsule and oozes a
slippery liquid called synovial
fluid.
• A joint cavity.
– A small gap between the
bones.
– Filled with synovial fluid.
– Lubricates the joint so the
joint moves more freely.
• A covering of smooth slippery cartilage at
the end of the bones.
– Stops the bones knocking
together.
• Ligaments which hold the bones together.
36. Lesson Overview The Skeletal System
• Ligament• Tendon
• Join bone to bone (joint) and
hold joints in place.
• Its matrix contains yellow
elastin fibres
• Elastic but tough
• Allows movement at the joint
• Connects muscle to bone
(normally one tendon to a
non-moving part and
another tendon to a
movable part)
• Its matrix contains white
fibrous collagen
• Tough and do not stretch
• They don’t stretch when
the muscle contracts to
move the bone
37. Lesson Overview The Skeletal System
Diseases and Conditions
of the Skeletal System
* Arthritis
* Bursitis Inflammation of the Bursa sac
*Tendonitis most common cause of tendonitis is overuse
of the tendons.
* Carpal Tunnel Syndrome: swelling or change in position of the
tissue within the carpal tunnel squeezes and irritates the median
nerve. It causes tingling and numbness of the thumb, index, and
the middle fingers
* Osteoporosis bones have lost minerals (especially calcium)
making them weak, brittle, and susceptible to fractures
38. Lesson Overview The Skeletal System
* Scoliosis abnormal curvature of the spine.
More girls than boys have severe scoliosis.
* Kyphosis spine may develop a hump
* Lordosis A curvature of the vertebrae in
the lower back area
*Rickets softening and weakening of
bones in children
*Acromegaly occurs when the body produces too much of the
hormones that control growth, tissues grow larger than
normal
39. Lesson Overview The Skeletal System
• How many muscles are there in the human body?
– Answer: 640 Muscles
– The muscles make up about 40 % of the body mass.
• What is the longest muscle in the body?
– Answer: The Sartorius
– The Sartorius runs from the outside of the hip, down and across to the
inside of the knee. It twists and pulls the thigh outwards.
• What is the smallest muscle in the body? Would you like to see it?
– Answer: The Stapedius
– The Stapedius is located deep in the ear. It is only 5mm long and thinner
than cotton thread. It is involved in hearing.
• What is the biggest muscle in the body?
– Answer: The Gluteus Maximus
– The Gluteus Maximus is located in the buttock. It pulls the leg backwards
powerfully for walking and running.
TRIVIA!
41. Lesson Overview The Skeletal System
Functions of the Muscles
• Movement
• Heat production
• Maintenance of posture and muscle
tone
• Protects the bones and internal
organs.
42. Lesson Overview The Skeletal System
Muscle Classification
• Functionally
–Voluntary – can be moved at will
–Involuntary – can’t be moved
intentionally
• Structurally
–Striated – have stripes across the fiber
–Smooth – no striations
43. Lesson Overview The Skeletal System
Chart Title
Skeletal Muscle Smooth Muscle Cardiac Muscle
3 Types of Muscles
The 3 Types of Muscles
44. Lesson Overview The Skeletal System
Smooth Muscle
• Fibers are thin and in layers
• No striations
• Single nuclei
• Involuntary
• Contracts and fatigues slowly
Found in the
* circulatory system (Lining of the blood vessels)
Helps in the circulation of the blood
*digestive system (Esophagus, stomach, intestine)
Controls digestion
*respiratory system Controls breathing
*urinary system (Urinary bladder) Controls
urination
45. Lesson Overview The Skeletal System
Cardiac Muscle
• Cells are branched and
appear fused with one
another
• Has striations
• Each cell has a central
nuclei
• Involuntary
• Found ONLY in the heart
• Contractions of the heart muscles pump blood
throughout the body and account for the heartbeat.
• Healthy cardiac muscle NEVER fatigues or else…
46. Lesson Overview The Skeletal System
Skeletal Muscle
Fibers are long and cylindrical
(arranged in bundles)
Has many nuclei
Has striations
Have alternating dark and light
bands
Voluntary
• Attached to skeleton by tendons
• Causes movement of bones at the joints.
• And yes… they do fatigue
what substance forms causing muscle fatigue???
47. Lesson Overview The Skeletal System
Functions of Skeletal Muscle
• Movement – muscle move bones by
pulling not pushing.
– Antagonists – muscles and muscle groups
usually work in pairs
– example the biceps flex your arm and its
partner the triceps extend your arm. The two
muscles are antagonists, i.e. cause opposite
actions.
– when one contracts the other relaxes.
– Levators – muscle that raise a body part.
49. Lesson Overview The Skeletal System
Functions of Skeletal Muscle
• Maintenance of posture or muscle tone
– We are able to maintain our body position because
of tonic contractions in our skeletal muscles. These
contractions don’t produce movement yet hold our
muscles in position.
• Heat production – contraction of muscles
produces most of the heat required to maintain
body temperature.
50. Lesson Overview The Skeletal System
Structure of Skeletal Muscle
• Composed of striated muscle cells
(=muscle fibers) and connective tissue.
– Most muscles attach to 2 bones that have
a moveable joint between them.
• The attachment to the bone that does
not move is the origin.
• The attachment to the bone that moves
is the insertion.
– Tendons anchor muscle firmly to bones.
Tendons are made of dense fibrous
connective tissue.
– Ligaments connect bone to bone at a joint.
51. Lesson Overview The Skeletal System
Structure of Skeletal Muscle
• Contribution of the nervous system
Electrochemical
impulses travel from
the frontal lobes
via motor nerves
to the muscle fibers
and cause them to
contract.
Sensation is a function of the
brain – impulses are
integrated in the parietal lobes
of the cerebrum (conscious
muscle sense) and in the
cerebellum (unconscious).
These activities promote
coordination.
53. Lesson Overview The Skeletal System
Structure of Skeletal Muscle
- Muscle cells are filled with 2 types of fine threadlike proteins
called myofilaments: myosin (thick) and actin (thin).
are arranged in the cells in small units called sarcomeres.
These structures slide past each other
causing the muscle cell to contract or
shorten.
54. Lesson Overview The Skeletal System
Muscle Contraction
• Sequence
– Electrical impulse
travels down a
motor neuron. It
causes an
electrical impulse
to spread over
the cell.
– The sarcomeres
shorten and the
muscle cell
contracts.
(FIBRES AND
CELLS CANNOT
ELONGATE)
55. Lesson Overview The Skeletal System
Movement of Muscles
• Origin: the attachment of
the muscle to the bone
that remains stationary
• Insertion: the attachment
of the muscle to the bone
that moves
• Belly: the fleshy part of
the muscle between the
tendons of origin and/or
insertion
origin
insertion
belly
56. Lesson Overview The Skeletal System
Categories of
skeletal muscle actions
• Categories Actions
• Extensor Increases the angle at a joint
• Flexor Decreases the angle at a joint
• Abductor Moves limb away from midline of body
• Adductor Moves limb toward midline of body
• Levator Moves insertion upward
• Depressor Moves insertion downward
• Rotator Rotates a bone along its axis
• Sphincter Constricts an opening
57. Lesson Overview The Skeletal System
Skeletal muscles usually work in pairs. E.g. The biceps
and triceps muscles
attached to the
scapula at the
top and to the
radius at the
bottom
flexor muscle.
extensor
muscle.
As they bring about opposite effects, the biceps and triceps are examples of
antagonistic muscles.
A small contraction of the muscle will produce a large movement at the end of the limb
58. Lesson Overview The Skeletal System
• After exercise =>HIGH LEVEL of O2 consumption
PERSISTS until the excess of LACTIC ACID is oxidized :
• Accumulation of Lactic acid causes
CRAMPS and MUSCULAR FATIGUE
Glucose
Glucose
PYRUVIC ACIDLACTIC
ACID
2 ATP
LACTIC
ACID
PYRUVIC ACID
BLOOD
MUSCLE
LIVER
CORI CYCLE
Only in EXTREME
MUSCULAR ACTIVITY
6 ATPGLUCO
NEO
GENESIS
OXYGEN DEBT
Volume of O2 needed to
complete oxidize the
lactic acid
60. Lesson Overview The Skeletal System
Long-term benefits of exercise.
•increase in size of the muscles used,
•reduction of heart rate and increase in
stroke volume,
•more enzymes made in the muscles,
•stronger ligaments and tendons,
•more flexibility at the joints,
•possibly loss of excess body fat,
•possibly reduced chance of premature heart attack
•Healthy body and mind.
61. Lesson Overview The Skeletal System
Injuries to JOINTS, MUSCLES and
BONES
• SPRAINS joint is forced beyond its normal
degree of movement ligament totally or
partially torn
• STRAINS violent contraction of the muscle
some of the fibres are torn
• DISLOCATIONS bones at a joint become
displaced as a result of a violent movement.
Usually ligaments also damaged
• FRACTURES a bone is broken
62. Lesson Overview The Skeletal System
Stages in the Healing of a Bone
Fracture
63. Lesson Overview The Skeletal System
There are about 60 muscles in the face.
Smiling is easier than
frowning.
It takes 20 muscles to smile and over 40 to frown.
Smile and make someone happy.