Anatomy and Physiology

1. Unit – 2
Skeletal
System

3. Description Of Bone
 A bone is a rigid tissue that constitutes
part of the skeleton in most vertebrate
animals.
 Bones protect the various organs of the
body, produce red and white blood cells,
store minerals, provide structure and
support for the body, and enable mobility.

4. Type Of Bone
 Long Bone - each long bone has
elongated shaft (diaphysis) and two
expanded ends (epiphyses) which are
smooth and articular.
 Example - humerus, radius, femur, tibia
and fibula

5.  Short Bones – small in size
 Example - tarsal and carpal bones

6.  Flat Bones - form boundaries of certain
body cavity
 Example – scapula, sternum

7.  Irregular Bone
 Example – vertebra, hip bone

8.  Sesamoid bone - these are bony nodules
found in the tendons or joint capsule.
 They have no periosteum
 Example patella

9.  Accessory Bones - are not always
present.
 Example - suture bone

10. Bone Cells
There are four types of cells in bone tissue
1. Osteoprogenitor (Osteo=Bone,
Pro=Procursor, Gen=to produce) - can
undergo mitosis and develop into
osteoblasts
2. Osteoblast(blast=Bud) - these are bone
forming cells that secrete collagen and
other constituents of bone tissue
3. Osteocytes(Cyte=cell) - these are the
mature bone cell derived from osteoblast
4. Osteoclast (clast=to break) - their function is
resorption of bone to maintain the optimum
shape this take place at bone surface
(Resorption = reabsorption)

12. Bone Formation
(Osteogenesis Or Ossification)
 Growth of the bone starts from the foetal
life and continuous up to adolescence
age.
 In the childhood age, bones are very soft
and weak but during adult is they
become strong and hard.

13. Ossification
It is the process by which the bone is
formed. Bone formation follow the two
processes:
1. Intramembranous ossification
2. Endochondral ossification

14. Intramembranous
(Intra=within, Membranous=membrane)
 It refer to formation of bone directly on or
within loose fibrous connective tissue
membrane.
 The bones developed in this way are skull
bone, mandible, clavicle

15. Endochondral
(Endo=within, Chondral=cartilage)
 In this cartilage is replaced by bone.
 It is mainly present in long bones

16. Bone Growth
 During childhood, bone throughout the
body enlarge by oppositional growth and
long bone lengthen by addition of bone
material at the epiphyseal plate.
 Growth in length of bone normally ceases
by age 25, although bones may continue
to thicken.

17. Functions Of Bone
Bone has variety of functions
 Assist in movement - skeletal muscle are
attached to bone. When muscles contract, they
pull bones and together they produce
movement
 Protection - bone protect many internal organ
from injury. For example, cranial bones protect
the brain, vertebrates around the spinal cord, rib
cage enclose the heart and lungs and hip bone
protect the pelvis organ from injury
 Support – bone provide a framework for the
body by supporting soft tissue and providing
point of attachment for many skeletal muscle

18.  Mineral homeostasis - it provide reservoir
of minerals, especially calcium,
Phosphorus. bones release these minerals
to maintain the balance inside the body
 Site of blood cell production - bone
marrow present inside the bone helps in
the production of red blood cell. this
process is called haemopoiesis
 Storage of energy - yellow bone marrow is
the chemical energy Reservoir. lipids are
stored in these cells

19. Joint Movement

21. Joint
 Joint is a junction between two or more
bones or cartilage. It is a device to permit
movements.

22. Cartilage
 Cartilage is connective tissue composed
of cells (condrocytes) and fibers.

23. Classification
 Fibrous joint (Immovable Joint)
 Cartilaginous joint (Slightly Movable)
 Synovial joint (Freely Movable)

24. Fibrous Joint
In fibrous joint the bones are joined by
fibrous tissues. These joint are immovable or
permit a slight degree of movement.
1. Suture – In skull
2. Syndesmosis – Bones are connected by
the interosseous ligament
3. Gomphosis – Root of tooth in its bony
socket

25. Cartilaginous Joint
In this type of joints the bones are joined by
cartilage. Partially moveable
 Fibrocartilage
 Pubic symphysis
 Intervertebral disc

26. Synovial Joint
Synovial joints are most mobile type of joints.
1. Ball And Socket – Flexion, Extension, Adduction, Abduction,
Circumduction And Rotation Ex. Hip Joint
2. Saddle – Flexion, Extension, Abduction, Adduction, And
Conjunct Rotation Ex. Sternoclavicular Joint
3. Condylar – Flexion, Extension And Limited Rotation Ex. Knee
Joint
4. Ellipsoid – Extension, Abduction, Adduction And
Circumduction Ex. Wrist Joint
5. Hinge – Flexion, Extension Ex. Elbow Joint
6. Pivot - Rotation Only Ex. Radio-Ulnar Joint
7. Plane - Gliding Movement Ex. Intercarpal joint

27. Next Class – Unit 3
The Muscular System