The musculoskeletal system consists of bones, muscles, cartilage, tendons and ligaments and works together to allow for movement and provide support to the body. It has three main functions - supporting the body, allowing for motion, and protecting vital organs. There are three main types of muscles - skeletal, smooth and cardiac. Skeletal muscle is voluntary and attached to bones via tendons. Smooth muscle is involuntary and found in internal organs. Cardiac muscle is only located in the heart. The skeletal system provides points of attachment for muscles, supports the body, protects organs, stores minerals, and makes blood cells. It consists of long, short, flat, irregular and sesamoid bones. Joints connect bones together and include fibrous

2. INTRODUCTION
 The Musculoskeletal system is a combination of the
skeletal, muscular & articular systems of the body &
is responsible for the movement & locomotion of
the body.
 The musculoskeletal system provides form support,
stability and movement to the body.
 The musculoskeletal system’s primary functions
include supporting the body, allowing motion and
protecting vital organs.

3. Bursae
Cartilage
Ligaments Tendons
Joints
Muscles
Bones
Musculoskeletal
System

4. MUSCLES
 Our skeletal system has more than 650 muscles,
most of them disposed in pair to provide movement.
 The muscles make up about 40 % of the body
mass.
 Muscular cells are called muscle fibers.
 Every fibers contain thousand of myofibrils.
 Inside each mayofibril there are many
myofilaments that are made of 2 proteins :
1] Actin (Thin)
2] Myosin (Thick)

5. FUNCTIONS
 Enable us to move our body parts
 Give us our individual shape
 Protect and keep in place our abdominal organs
 Enable us to maintain good posture
 Help in the circulation of our blood
 Generate body heart when they contract
 Heat production

8. SMOOTH MUSCLE
 Also called as Visceral
muscle
 Non-striated, Involuntary
(No conscious control)
 Spindle-shaped cells
 Slow, sustained and
tireless

9.  Found in walls of the
digestive tract, bladder,
various ducts, arteries,
veins and other internal
organs.
 Controlled by the
Autonomic Nervous
System (ANS)
 Smooth muscle cells are
elongated & thin, have
one nucleus and form
sheets rather than
bundles of muscles.

12. SKELETAL MUSCLE
 Striated, Voluntary muscle, is the most abundant
tissue in human body, it produces movement.
 Attached to skeleton by tendons
 Cells - Multinucleated
 Each skeleton-muscle fiber is roughly cylindrical,
contains many nuclei & is crossed by alternating
light & dark bands called striations.
 Controlled by Somatic Nervous system
 The skeletal muscles are composite structures
composed of many muscle fibers, nerves, blood
vessels and connective tissue.

17. SARCOMERE
 Sarcomere is the Functional unit of the Skeletan Muscle
 About 10,000 sarcomeres per microfibril, end to end
 A single sarcomere consists of 2 – Z lines and 1 A band
and 2 semi – I bands.
 COMPOSITION :
 H – only Thick filaments
 A – Thick and Thin filaments
 I – only Thin filaments

19. CARDIAC MUSCLE
 Only found in the Heart
 Controlled by Autonomic Nervous System
 Has striations (similar like skeletan muscle)
 Involuntary
 Cells are branched and fused with one another
 Contractions of the heart muscle pump blood
throughout the body and account for the heartbeat.
 Cells are short, branching & have a single nucleus
 Never tired

20. Cells connect to each other at Intercalated
discs

21.  Cardiac muscle cells – CARDIOMYOCYTES
 It has got numerous Mitochondria.
 Rhythemic contraction

22. SKELETAN
SYSTEM

24. FUNCTIONS
 Movement – Skeletal system provides points for
attachment for muscles.
 Support – It holds your head up and protects your
spinal cord.
 Protection – The bones of your skull protect your
brain, ribs protect your lungs & heart from injury.
 Make Blood – RBCs & WBCs are formed by tissue
called marrow.
 Storage – stores mineral such as Ca and Mg

25. BONES
 The human skeleton is the internal framework of the
body.
 It is composed of 270 bones at birth – this total
decreases to 206 bones by adulthood after some bones
have fused together.
 The human skeleton can be divided into :-
1) The Axial Skeletan
2) The Appendicular Skeletan

26. AXIAL SKELETAN
 The Axial skeleton (80 bones) is
formed by the vertebral column,
the rib cage, the skull & other
associated bones.
 It Protects the major organs of
the nervous, respiratory and
circulatory system.

29. APPENDICULAR SKELETAN
 The appendicular skeleton (126 bones), which is
attached to the axial skeleton, is formed by the
shoulder girdle, the pelvic girdle & the bones of
the upper and lower limbs.
 It makes the body movement possible and also
protects the organs of digestion, excretion, and
reproduction.

31.  Compact Bone
o Osteocytes occupy small
cavities or lacunae at the
junctions of lamellae
 Spongy Bone
o Consisting of trabeculae
o Function as struts of bone
o Trabeculae contain
irregularly arranged
lamallae & osteo-cytes
interconnected by canaliculi

32. BONE CELLS
[1] Osteogenic cells
- Develop into Osteoblasts
[2] Osteoblasts cells
- growing portion of bone, including periosteum
and endosteum
[3] Osteocytes cells
- maintain mineral concentation of matrix
[4] Osteoclasts cells
- Bone resorption

34. CLASSIFICATION OF BONES
[1] Long Bones
 Long bones have a
long shaft and two
distinct ends
 All bones of the limbs
{except patella, wrist &
ankle}
 The bones of the
fingers
 They are usually
somewhat curved for
strength

35. [2] SHORT BONES
 Short bones are roughly
cubelike
 Cube-shaped & have
approximately equal length
& width
 Providing support and
stability with little
movement
 Found in wrist & ankle
bones

36. [3] FLAT BONES
 Flat bones are thin,
flattened and usually
curved
 Provide considerable
mechanical protection &
extensive surfaces for
muscle attachments
 Ex. Scapula, Sternum,
Ribs, cranial bones

37. [4] IRREGULAR BONES
 Irregular bones don’t fit
into the previous
categories
 Complicated shapes
 Consist of cancellous
bone with a thin outer
layer of compact bone
 Ex. Vertebrae, Mandible,
Hip, Sacrum

38. [5] SESAMOID BONES
 Short or irregular
bones, imbedded in a
tendon
 It passes over a joint
which serves to
protect the tendon
 Ex. Patellae
(kneecaps)

40. JOINTS
 Also called as “Articulation”, where bone and
cartilage come together to form a connection.
 Joints classified by Structures into 3 types :-
1) Fibrous joint - Immovable
2) Cartilaginous joint – partly movable
3) Synovial joint – freely movable

41. FIBROUS JOINT
 All the bones of the skull,
except for the mandible,
are joined to each other
by a fibrous joint called a
suture.
 joined by dense regular
connective tissue that is
rich in collagen fibers.

44. SYNOVIAL JOINT
 Also called as
“Diarthrosis”
 The synovial (or joint)
cavity is filled
with synovial fluid.
 most common and most
movable type of joint in
the body of a mammal

46. CARTILAGE
 Cartilage is a
flexible connective tissue ,
including the joints
between bones, the rib cage,
the ear, the nose, the bronchial
tubes and the intervertebral
discs.
 Cells - CHONDROCYTES
 Grows fast--forms embryonic
skeleton

47. KINDS OF CARTILAGE
 Hyaline cartilage --
most common, found
in joints
 Elastic cartilage --
epiglottis, ear
 Fibro cartilage --
annular fibrosis of
intervertebral disk,
menisci of knee

48. TENDON
 A tendon (or sinew)
is a tough band
of fibrous connective
tissue that usually
connects
muscle to bone and is
capable of
withstanding tension.
 Tendons are similar to ligaments; both are made
of collagen. Ligaments join one bone to another
bone, while tendons connect muscle to bone

49. LIGAMENT
 A Ligament is the fibrous connective tissue that
connects bones to other bones and is also known
as articular ligament, articular larua, fibrous ligament,
or true ligament.
 Ligaments are similar to tendons and fasciae as they
are all made of connective tissue.
 The differences in them are in the connections that
they make; ligaments connect one bone to another
bone, tendons connect muscle to bone and fasciae
connect muscles to other muscles.

51. OSTEOMALACIA
 Osteomalacia is the softening of
the bones caused by deactivated bone
mineralization primary to adequate levels of
available phosphate & calcium.
 The most common cause of osteomalacia is a
deficiency of vitamin D, which is normally derived
from sunlight exposure and, to a lesser extent,
from the diet.

52. SYMPTOMS
 Muscle weakness
 Difficulty walking, often with waddling gait
 Hypocalcemia
 Compressed vertebrae and diminished stature
 Pelvic flattening
 Weak, soft bones
 Easy fracturing
 Bending of bones
TREATMENT
 Include daily sufficient Vitamin D , Protein

53. PAGET’S DISEASE
 It is chronic disease of skeletan
 Normal growth of bone is changed
 Bones break down more quickly
 Bones can grow larger than before
 Bone that replaced is soft and porous
 Symptoms :
 Pain in or over a bone
 The affected area may be feel extra warm
 The shape of bone may be change
 Bone of legs may blow out or bend
 The bone in the skull may get bigger

55. QUESTIONS

56. [1] Bones that surround the spinal cord are classified as
________ bones.
A. Short
B. Sesamoid
C. Flat
D. Irregular
E. Long

57. ANSWER:
(D) Irregular

58.  [2] What is the difference between compact bone
and spongy bone?
A. They have different bone marrow.
B. They are made of different materials.
C. They have different sizes of bone cells.
D. They have different arrangement of bone cells.

59. ANSWER:
(D) They have different
arrangement of bone cells.

60. [3] A joint between radius and carpal bone is known
as ..
A. Hinge joint
B. Saddle joint
C. Ball and socket joint
D. Condyloid joint
E. Plane joint

61. ANSWER:
(D) Condyloid joint

62. [4] The tissue that surrounds a muscle cell (myofiber)
is known as……
A. Epimysium
B. Perimysium
C. Endomysium
D. Exomysium
E. Superficial mysium

63. ANSWER:
(C) Endomysium