The skeletal system is composed of 206 bones and provides support, protection, movement, blood cell production, calcium storage, and endocrine regulation. It consists of two divisions: the axial skeleton which includes the skull, vertebral column, rib cage, and hyoid bone, and provides support and protection for internal organs; and the appendicular skeleton of 126 bones including the pectoral girdle, upper and lower limbs, and pelvic girdle. Cartilage, found at joints, provides flexibility and cushioning between bones. The three types are hyaline, fibro, and elastic cartilage located in various parts of the body.

1. The Skeletal System
PBL – G5 Case
1

2. The Skeletal System
▪ Is the body's framework of bones which consists of 206
bones of an average adult human, as well as a network of
tendons, ligaments and cartilage that connects them.
▪ Performs vital functions — support, movement, protection,
blood cell production, calcium storage and endocrine
regulation — that enable us to survive.

3. :Tow major division of the skeleton

4. :Growth of the Skeleton
▪ A baby's body has about 300 bones at birth. These eventually fuse (grow
together) to form the 206 bones that adults have. Some of a baby's bones are
made entirely of a special material called cartilage (say: KAR-tel-ij). Other
bones in a baby are partly made of cartilage. This cartilage is soft and flexible.
During childhood, as you are growing, the cartilage grows and is slowly
replaced by bone, with help from calcium.
▪ By the time you are about 25, this process will be complete. After this
happens, there can be no more growth — the bones are as big as they will ever
be.
▪ All of these bones make up a skeleton that is both very strong and very light

5. (Bone Growth (Ossification prosses

6. The Function of Skeleton
▪ 1. Support: The skeleton is the framework of the body, it supports the softer
tissues and provides points of attachment for most skeletal muscles.
▪ 2. Protection: The skeleton provides mechanical protection for many of the
body's internal organs, reducing risk of injury to them.
For example, cranial bones protect the brain, vertebrae protect the spinal cord,
and the ribcage protects the heart and lungs.
▪ 3. Assisting in Movement: Skeletal muscles are attached to bones, therefore
when the associated muscles contract they cause bones to move.

7. The Function of Skeleton
▪ 4. Storage of Minerals: Bone tissues store several minerals , including
calcium (Ca) and phosphorus (P). When required, bone releases minerals into
the blood - facilitating the balance of minerals in the body.
▪ 5. Production of Blood Cells: The red bone marrow inside some larger bones
produces blood cells.
▪ 6. Storage of Chemical Energy: With increasing age some bone marrow
changes from 'red bone marrow' to 'yellow bone marrow'. Yellow bone marrow
consists mainly of adipose cells, and a few blood cells. It is an important
chemical energy reserve.

8. :Structure of the Skeleton
▪The skeletal system consist of several connective tissues
such as bones, ligaments, joints, tendons and
cartilage.

9. Bones
▪There are two basic types of bone tissue:.
▪ 1- Compact bone:
a- Homogeneous
▪ 2- Spongy bone:
a- Small needle-like pieces of bone
b- Many open spaces

10. Structure of Bones
▪ The bones in the skeleton are not all solid.
▪ The outside cortical bone is solid bone with
only a few small canals.
▪ The insides of the bone contain trabecular
bone which is like scaffolding or a honey-comb.
▪ The spaces between the bone are filled with
fluid bone marrow cells, which make the
blood, and some fat cells.

11. Tendons & Ligaments

12. ▪joints part) Joints)
▪Joints—also called articulations—are formed where the surfaces of two or more bones meet and articulate with each other. So that we can bend, stretch, twist and
.turn easily – but within certain limits. Most of our joints are designed to allow bones to move only in certain directions
▪.Functionally, joints can be classified by the degree of movement possible, the number of bones involved, and the complexity of the joint
▪.Joints are usually classified structurally by the tissue that connects them. The tissue could be cartilage, fibrous tissue, synovial fluid, or some combination of the three
▪Types of Functional Joints
▪immovable joints—the bones are held together by fibrous tissue so they don’t move at all; example is the skull bones
▪slightly movable joints—the bones are held together by cartilage that allows only a little movement; examples are the joints in the spine
▪freely movable joints—also called synovial joints, allow the most movement; examples are hip and knee joints
▪Types of Structural Joints
▪.Fibrous joint :A joint where two or more bones are fused together by tough, fibrous connective tissue (example: skull sutures); this is the least moveable joint of the body
▪Cartilaginous joint :A joint where two or more bones are held together by a piece of cartilage (example: vertebrae or pubic bones); these joints are slightly moveable
▪Synovial joint :The most common joint in humans and also the most complex; contains two key characteristics: surrounded by a joint capsule and contains synovial fluid; also
.the most highly moveable joint in humans
▪Synovial fluid :Fluid found within synovial joints to reduce wear and tear and to nourish the structures inside of the joint capsule.A joint capsule is a piece of tissue that
.surrounds a synovial joint. Its purpose is to hold the synovial fluid of the joint in place, as well as to provide an envelope for the entire joint
Joints

13. ▪(Add definition)cartilage

14. ▪skeletal system is the body's framework of bones; there are 206 distinct bones in the
body of an average adult human. The bones give support and shape to the body,
protect delicate internal organs, and provide sites of attachment for muscles to make
motion possible. In addition, they store and help maintain the correct level of calcium,
.and the bone marrow manufactures blood cells

15. Since most bone begins as cartilage, it must be converted to bone
through a process called ossification. The key players in bone
development are cartilage cells (chondrocytes), bone precursor
cells (osteoprogenitor cells), bone deposition
cells (osteoblasts), bone resorption cells (osteoclasts) and mature
(bone cells (osteocytes
Bone Development And Growth

16. ▪Support .1
▪The skeleton is the framework of the body, it supports the
softer tissues and provides points of attachment for most
.skeletal muscles
▪Protection .2
▪The skeleton provides mechanical protection for many of the
body's internal organs, reducing risk of injury to them.
For example, cranial bones protect the brain, vertebrae protect
.the spinal cord, and the ribcage protects the heart and lungs
▪Assisting in Movement .3
▪Skeletal muscles are attached to bones, therefore when the
.associated muscles contract they cause bones to move
Functions of The Skeleton

17. ▪Storage of Minerals .4
▪Bone tissues store several minerals , including calcium (Ca) and phosphorus (P). When required, bone
.releases minerals into the blood - facilitating the balance of minerals in the body
▪Production of Blood Cells .5
▪.The red bone marrow inside some larger bones produces blood cells
▪Storage of Chemical Energy .6
▪With increasing age some bone marrow changes from 'red bone marrow' to 'yellow bone marrow'.
Yellow bone marrow consists mainly of adipose cells, and a few blood cells. It is an important
.chemical energy reserve
▪
▪

18. The axial skeleton
▪The axial skeleton provides support and protection to the brain,spinal
cord,and the organs in the vetebral body:it also provides a surface for
attarchment of muscles,directrespiratory movement,and stabilize portion of
.the appendicular skeleton

19. Parts of the axial skeleton
▪Skull
▪Vertebral colunm
▪(Thoracic cage(rib cage
▪Hyoid

20. The skull
• The skill has two set of bones
• Cranium bones
• Facial bones
• Which are all connected by sutures and have sinuses
which are hollow cavities within the bones

21. Hyoid bone
• Support the larynx and is a point of
attarchment for muscles of the
larynx,pharynx and tongue.

22. Vertebral column
The vertbral column jas 26 bones which are
▪vertebrae 24
▪Sacrum
▪Coccyx
It also has the intervertebral discs which
serve
as cushioning between two vertebrae

23. Thoracic cage
▪pairs of ribs 12
(Sternum(breast bone
Manubrium
Body
Xiphoid process
Costal cartilage

24. ▪The Appendicular Skeleton
▪There’re 126 bones in the Appendicular Skeleton and It consist of four parts, Upper limbs ,
.Shoulder girdle , Lower limbs , Pelvic girdle
▪
▪Upper Limb Bones
▪Humerus : the long bone of the upper arm
▪: The long bones of the forearm, that connects with the humerus to form the elbow are
▪Radius - Ulna
▪Shoulder(Pectoral) Girdle
▪:Composed of two
▪Clavicle: collar bone
▪Scapula: shoulder bone

25. ▪Lower Limb Bones
▪Femur: Long bone of the thigh and longest bone in the body
▪Tibia: Long bone of the leg
▪Fibula: thinner , long bone of the leg
▪Pelvic Girdle
▪Made up of the right and the left hip bones
▪.The Hipbones: made up of
▪Ilium – Sacrum – Pubic bone
▪:The pelvic girdle protects several organs
▪Reproductive organs – Urinary bladder – Part of the large intestine
▪

26. THERE ARE THREE TYPES OF
:CARTILAGE NAMELY
Hyaline cartilage
Fibrocartilage
Elastic cartilage

27. Cartilage
▪Cartilage is a tough but flexible tissue that is the main type of connective
.tissue in the body
▪.Its is made up of chondrocytes that are isolated in chambers called lacunae
▪It consists of 60%-80% of water and the rest is gel like substance called the
.matrix
▪It is surrounded by a layer of dense irregular connective tissue known as
.perichondrium
▪.Its is located in very specific places, usually between two bones

28. FUNCTIONS OF THE CARTILAGE
The hyaline cartilage tissue provides smooth surfaces, it also provides
flexibility and support
Fibrocartilage provides support and rigidity to attached surrounding and it’s
the strongest of the three types
Elastic cartilage provides support to surrounding structures and helps the
define and maintain the shape of the area in which its present

29. Locations of cartilage
▪Hyaline cartilage is the most abundant of the three types and is found in the
:bronchi, larynx, nose, trachea, embryonic skeleton i.e in the fetus
▪Fibrocartilage is found in the :calli, invertebral discs, mrnisci,pubic
symphysis
▪Elastic cartilage is found in the: auditory tubes, external ear auricle and
epiglottis

30. Locations of cartilage
Hyaline cartilage is the most abundant of the three types and is found in the
:bronchi, larynx, nose, trachea, embryonic skeleton i.e in the fetus
Fibrocartilage is found in the :calli, invertebral discs, mrnisci,pubic symphysis
Elastic cartilage is found in the: auditory tubes, external ear auricle and
epiglottis

31. Types of cells in the skeletal system
Osteoprogenitor Cells: These are immature cells that are primarily located in the bone marrow and periosteum
.(membrane that lines the surface of all bones). They mature into the osteoblasts, another type of bone cell
Osteoblast Cells: These are the bone cells that are primarily responsible for bone formation. They only have one
nucleus and are derived from osteoprogenitor cells. They function by secreting a substance called osteoid, which is also
known as the bone matrix. Their job is to regulate the passage of minerals, such as calcium, in and out of the bone.
.They also function by secreting proteins that regulate the osteoclast cells
Osteoclast Cells: These are the cells that are primarily responsible for dissolving bone tissue, also known as resorption.
They do not arise from osteoprogenitor cells; instead, white blood cells that normally have immune system function
(monocytes) fuse together to create the osteoclasts. As a result, they are quite large, with multiple nuclei, and are
.(located in the endosteum (membrane that lines the inner cavity of the bone where bone marrow resides
Osteocytes: These can be recognized by their typical star-shaped appearance, and are mature osteoblasts that do not
.secrete the osteoid bone matrix, but are surrounded by it
.Together, the osteoblasts and osteoclasts perform bone remodelling
/Reference: http://www.livestrong.com/article/72443-specialized-cells-skeletal-system
Bone as a supporting connective tissue
Bone is a form of connective tissue. The matrix is hard and calcified arranged in a circular way giving the characteristic
appearance of Haversian system or osteon (is the fundamental functional unit of much compact bone). The bone stores
calcium (for healthy bones) and phosphorus (for strong bones and teeth). It also gives support and protection to the
.body

32. Common Skeletal System Diseases
.
Arthritis is a joint disorder causing inflammation and pain in the affected area. There are several forms of
.arthritis. most common as osteoarthritis and rheumatoid arthritis
.Arthritis exists in two main forms
Osteoarthritis is a chronic degenerative joint disease. Especially kneens and hips. All joints are lined with
cartilage to provide cushioning and synovial fluid to help lubricate the joint through a range of motion. Over
time, these tissues break down and wear away leading to bone spur formation, joint narrowing, inflammation
.and pain
Autoimmune arthritis occurs when the body attacks itself and damages joints. Rheumatoid arthritis is one
.example and over time, results in severe joint destruction and chronic debilitation
▪Osteoporosis
As bone mineral density decreases, bones loose their integral strength. Age, hormone status and diet all play
.a vital role in osteoporosis. Bones become progressively weak and are prone to fractures with minor trauma

33. Rickets/ Osteomalacia .3
Rickets is caused from a severe deficiency of calcium, vitamin D and phosphate. Bones soften
and become weak losing their normal shape. Bone pain, muscle cramps and skeletal deformities
.occur
Tendinitis .4
Overuse or injury of the tendons results in inflammation and pain. Tendons connect muscle to
bone and facilitate movement. Commonly affected areas include the knee, elbow, wrist and
Achilles’ tendon. Treatment includes rest, ice and modifying activities until the pain and
.inflammation resolve
Clubfoot .5
Clubfoot is a birth defect resulting one or both feet pointing inward and downward. This makes
learning to walk difficult and specialized orthopedic therapy or surgery is often required. The
.medical term for this condition is talipes equinovarus

34. ▪Bursitis .6
▪The bursa are specialized sacs of fluid found around our joints. They provide
cushioning between the joints and nearby muscle, tendon and ligaments.
The well-known condition of 'water on the knee' is an example of prepatellar
.bursitis. This condition causes pain, swelling and mild redness
▪Spina Bifida .7
▪This birth related condition results in incomplete closure of the vertebra
around the spinal canal. Many people have a mild form and do not even
know it. More severe forms are accompanied by nerve defects, difficulty
.walking at problems with bowel and bladder function
▪Leukemia .8
▪White blood cells are produced in part by the bone marrow. A variety of
blood cancers are generally termed leukemia. The onset is generally
insidious and until a critical mass of abnormal cells occurs, most people are
without symptoms. Early warning signs include: bone pain, excess fatigue,
.easy bruising, night sweats, unexplained weight loss and bleeding gums

35. ▪Bone Cancer .
▪Tumors can arise in bones in a similar fashion as other solid organ cancers. Bone cancer can
occur as a primary type of cancer or can be a sign of an advanced cancer located elsewhere in
the body that has spread (metastasized) to the bones. Primary bone cancers include
.osteosarcoma and Ewing's. Metastatic cancer examples include lung, breast and prostate
▪

36. Different between
skeletal system in
both sex

37. Male skeleton system Female skeleton system
Has pelvic cavity which is narrower and less
roomy
Has pelvic cavity which is wider and deeper
Has coccyx (tailbone) which is less movable Has coccyx which is more movable
Has thick and heavy pelvis Has light and thin pelvis
Has large joint surface Has small joint surface
Has deep grater pelvis Has short grater pelvis
Has pubic arch less than 900 Has pubic arch more than 900
Has inward turned ischial tuberosity Has outward turned ischaial tuberosity
Smaller pelvic inter and outer Has larger pelvic inter and outer
Has narrow sciatic notch Has wider sciatic notch

38. Children have more
.bones than adults

39. The skeletal system in an adult body is
.made up of 206 individual bones

40. When a child is born, there are
270 bones that make up the
.human skeletal system

41. children’s bones tend to be more
.flexible than adults
▪This is because of the large amount of
.cartilage

42. We are born with more than 300
bones.
Many of these bones fuse together as
.a child grows into an adult

43. Joints
▪Joints—also called articulations—are formed where the surfaces of two or more
bones meet and articulate with each other. So that we can bend, stretch, twist
and turn easily – but within certain limits. Most of our joints are designed to allow
.bones to move only in certain directions
▪Functionally, joints can be classified by the degree of movement possible, the
.number of bones involved, and the complexity of the joint
Joints are usually classified structurally by the tissue that connects them. The tissue
.could be cartilage, fibrous tissue, synovial fluid, or some combination of the three
▪Types of Functional Joints
▪immovable joints—the bones are held together by fibrous tissue so they don’t
move at all; example is the skull bones
▪slightly movable joints—the bones are held together by cartilage that allows only
a little movement; examples are the joints in the spine
▪freely movable joints—also called synovial joints, allow the most movement;
examples are hip and knee joints

44. ▪Types of Structural Joints
▪Fibrous joint :A joint where two or more bones are fused together by tough, fibrous
.connective tissue (example: skull sutures); this is the least moveable joint of the body
▪Cartilaginous joint :A joint where two or more bones are held together by a piece of
cartilage (example: vertebrae or pubic bones); these joints are slightly moveable
▪Synovial joint :The most common joint in humans and also the most complex;
contains two key characteristics: surrounded by a joint capsule and contains synovial
.fluid; also the most highly moveable joint in humans
▪Synovial fluid :Fluid found within synovial joints to reduce wear and tear and to
nourish the structures inside of the joint capsule.A joint capsule is a piece of tissue
that surrounds a synovial joint. Its purpose is to hold the synovial fluid of the joint in
.place, as well as to provide an envelope for the entire joint