5. skeletal muscle system
TRANSCRIPT
SKELETAL MUSCLES.S.MOORTHY SEMENCHALAM
M.Sc. Comm Health (Occ Health) UKMB.HSc. Nursing (Aust)
Dip Med Sc. (Moh)
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Learning Objective
At the end of these session students should be able to:• State the 2 classifications of bones• List the functions of bones• Name the types of bones• List the composition of bone• List the types of joints• Described 3 types of muscle tissue• State the characteristics & structure of muscle tissue• State the relations of muscle and movement
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Classification of Bones
Axial Skeleton – forms the long axis of the bodyeg. bones of the skull, vertebral column,
rib cage, hyoid bone
Appendicular Skeleton – relating to an appendage, 126 boneseg. bones of the upper and lower limbs, shoulder girdle, hip girdle
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1. BONE
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Functions:Axial skeleton/bones Involved in protecting and supporting of
the body and organsAppendicular skeleton/bones Help in movement
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Functions of Bones
• Support – forms the framework (central axis of body); gives shape, supports the body
• Protection – provide protective case for brain, spinal cord & organs ( heart & lungs)
• Movement – provide levers for muscle• Mineral storage – reservoir for minerals; e.g.
calcium & phosphorus• Blood cell formation – haematopoiesis occurs
within the marrow cavities of bones• Attachment for muscles & tendons04/12/23 6 7
Number of Bones
There are 206 bones in our whole body• Upper limbs - 64• Lower limbs - 62• Vertebrae - 33 ( C7,T12,L5,S5,CO4 )• Skull - 22• Ribs - 24• Sternum - 1 04/12/23 7 8
Sesamoid bones
Irregular bones
Flat bones
Short bones
Long bones
Types of bones
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i. LONG BONES
• Bones of the extremities• Cylindrically in shape (shaft) with
expanded end• E.g. femur,humerus, tibia, fibula
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ii. SHORT LONG BONES & SHORT BONES
• Describes the bones of the hand & foot• E.g. metatarsal, metacarpal,carpals, tarsals
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iii. FLAT BONES
• Like flat plate; curved or straight• E.g. sternum,
scapula & parietal
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iv. IRREGULAR BONES• Shape cannot be described because it is irregular• E.g. vertebrae, pelvic bone
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v. SESAMOID BONES
• Seed- like bones seen in tendon eg.patella (knee cap)
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GROSS ANATOMY OF BONES
• External features of bones – projections, depression & openings- as sites for muscle, ligament & tendon attachment- as surface joints- conduits for blood vessels & nerves
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Internal features:• Compact bone –
dense outer layer & hard
• Spongy bone less hard (cancellous bone) – honeycomb of trabeculae filled with bone marrow
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Structure of Typical Long Bone• Diaphysis
- tubular shaft; forming the axis of long bones- composed of compact bone + central medullary canal (houses fatty yellow bone marrow)
• Epiphysis- expanded end of long bones- spongy bones inside
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Con`tThin layer of articular
cartilage covers end of epiphysis
Long bone that are still growing has an epiphyseal plate or growth plate
When the bone growth stops, the epiphyseal plate is replaced by bone- epiphyseal line
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Structure of Typical Long Bone: Periosteum
double-layered protective membrane
supplied with nerve fibers, blood, and lymphatic vessels entering the bone via nutrient foramina
Secured to underlying bone by Sharpey’s fibers (collagen)
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AXIAL SKELETONAXIAL SKELETON
1. Skull2. Vertebral column3. Thoracic cage
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1. Skull1. Skull
• Consist of 2 parts1. Cranium – contain the brain2. The face
• Fused/ joined bones – not moveable• Mandible bone – moveable
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Consist of 11 bones1. Frontal bone2. Parietal bone3. Temporal bone4. Occipital bone
5. Sphenoid bone6. Nasal bone7. Lacrimal bone8. Ethmoid bone9. Zygomatic bone10.Maxilla bone11.Mandible bone
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Frontal
Parietal
Temporal
occipital
Mandible
Maxilla
zygomatic
Nasal
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Function of the skullFunction of the skull
1. Cranial bones protect the brain2. Bone eye sockets protect the eye3. Temporal bone protects the ear4. Gives resonance of voice due to the air filled
cavities called sinuses5. Keeps the air passage open to facilitate
breathing04/12/23 27 32
2. Vertebral Column2. Vertebral Column• Consist of 24 movable bones• Sacrum & coccyx• Separated by intervertebral discs (cartilage)
i. 7 cervicalii. 12 thoraciciii. 5 lumbariv. 5 sacrum v. 4 coccyx
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1. Protects the spinal cord. 2. Houses 31 pairs of spinal nerves going
through the foramina3. Vertebrae articulate with the ribs, forming
joints which move during respiration.
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Functions of vertebral column
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3. Thoracic cage3. Thoracic cage
• Formed by 12 thoracic vertebrae• 12 pairs of ribs• 1 sternum/ breast bone• The ribs are attached to the sternum by costal
cartilage• Two pairs of ribs (rib 11 & 12) –called as floating ribs-
no anterior attachment
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1) Protects heart, lungs, major blood vessels 2) Forms joints between the upper limbs and the
axial skeleton.3) Manubrium (upper part of sternum),
articulates with the clavicle bones4) Gives attachment to the respiratory muscles
to enables respiration
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Functions of thoracic cageFunctions of thoracic cage
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The Sternum (breast bone )
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APPENDICULAR SKELETONAPPENDICULAR SKELETON
1. Shoulder girdle and the upper limb/extremity2. Pelvis girdle and the lower limb/extremity3. Arches of the foot
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LigamentsLigaments
• A band of fibrous tissue that connects bones or cartilages
• Function: support and strengthen joints
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2. JOINTS
Joints = Articulations
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Articulation – site where two or more bones meet
Two Fundamental Functions of Joints:Allow the skeleton to have mobilityHold the skeleton together
Classification of Joints: Structural
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Fibrous Cartilaginous
Synovial
Classification of Joints: Functional
Fibrous joints – immovableCartilaginous joints – slightly movableSynovial joints – freely movable
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Structural - Fibrous Joints
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-The bones are joined by fibrous tissues
- No joint cavity
- Most are immovable (synarthroses)
Example of fibrous joint
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Example of fibrous joint
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Example of fibrous joint
Structural – Cartilaginous Joints
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- Articulating bones are joined by cartilage- No joint cavity
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Example of cartilaginous joint
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Example of cartilaginous joint
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Example of cartilaginous joint
Structural – Synovial Joints
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Articulating bones are separated by a joint cavity containing fluid
All are freely movable diarthroses
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Example of synovial joint
Synovial Joints: General Structures
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Synovial Joints: Friction-Reducing Structures
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Synovial Joints: Range of Motion
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Nonaxial – slipping movements onlyUniaxial – movement in one planeBiaxial – movement in two planesMultiaxial – movement around all planes
Three General Types of Movements:
Gliding (slipping)AngularRotation
Gliding (slipping) movements
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One flat bone surface glides or slips over another bone
Angular movements
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Involve change of angle between bones
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Flexion - bending movement that decreases the angle of the joint
Example of angular movement
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Example of angular movement
Extension-straightening movement that increases the angle of the joint
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Dorsiflexion & Plantar flexion- Up and down movement of the foot
Example of angular movement
• Abduction — movement of a limb away from the midline or median plane
• Adduction — movement of a limb toward the midline or median plane
• Circumduction — movement of a limb describing a cone in space
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Example of angular movement
Rotation movements
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Turning of a bone around its own axis
Example:
Hip and shoulder joints
Special Movements
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Supination and Pronation – movements of radius around the ulna –
Special Movements
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Protraction and Retraction
Inversion and Eversion
Special Movements
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Elevation and Depression
Opposition
Types of Synovial Joints-Diarthrotic
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Six Major Categories:
Plane Condyloid
Hinge Saddle
Pivot Ball-and-Socket
Types of Synovial Joints - Hinge
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Motion is along a single plane (only permits flexion and extension)
Resembles action of a hinge
Examples: elbow joint knee joint
Ball & socket
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Example :SHOULDER JOINTHIP JOINT
Condyloid
• Oval shaped condyle
• Angular motion but not rotation
Example : Occipital condyles with atlas; metacarpals & metatarsals with
palanges
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Saddle• Articulating surfaces of both bones (concave &
convex regions)• Permits wide range of movement Example: Carpometacarpal joint of thump is
the only saddle joint in the body 04/12/23 69
Pivot
• Rounded or conical surface of one bone fits into a ring of bone or tendon
• For rotation
Example: Joint between the atlas and axis; proximal radioulnar joint04/12/23 70
Gliding/Plane
• Flat or lightly curved surfaces • Moving against each other• Sliding or twisting without circular movement Example: Between carpals (wrist) & tarsals ( ankle)
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3. MUSCLE
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MUSCLE TISSUE• Study of muscles is called Myology• Muscles form 40-45% of total body
weight• Motion - essential body function that
results from the contraction and relaxation of muscles
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Cont..
• Posture maintaining both during rest and at activity• Heat generated by skeletal muscle contraction
produce 80% of all the body heat• Beating of heart is specific function of cardiac muscle• Smooth muscle throughout body help in movement
of secretions, waste products, etc.
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TYPE OF MUSCLE TISSUE
• 3 Types of muscle in the body - skeletal muscle - cardiac muscle - smooth muscle
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Types- skeletal muscle• 40 % of body weight• It is voluntary as it can be made to contract and
relax at conscious level• Also called as striated muscle• Eg: diaphragm is structurally voluntary but it
works automatically with breathing• Upper part of esophagus is voluntary but is not
under conscious control
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Skeletal muscle tissueOver 600 muscle in bodySkeletal muscle tissue has three
components (epimysium, perimysium, endomysium)
- Connective tissue component- Nerve and blood supply- Muscle tissue proper04/12/23 77
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Blood supply• Skeletal muscle fibers are well supplied by
nerve and vessels which help in contraction, supply energy and transfer of waste products
• Generally an artery and two veins accompany the nerve that penetrate skeletal muscle
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Skeletal muscle and movementSkeletal muscle and movement• It produces movement by exerting force
on tendons which in turn pulls on bones or other structures like skin
• They cross at least one joint and are attached to articulating bone that form joint.
• Abundant blood & nerve supply04/12/23 81
Group actions
- Skeletal muscle act in groups- They are arrange in opposing pairs in joints
like flexor and extensors- Muscle that produce desired movement is
called prime movers / agonist- Muscle moving opposite are relaxing are
antagonist
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• MOST SKELETAL MUSCLES WORK IN PAIRS.
• When one muscle or set of muscles CONTRACTS, the other RELAXES.
• The Muscles of the upper arm are a good The Muscles of the upper arm are a good example of this dual action: example of this dual action: ANTAGONISTIC MUSCLESANTAGONISTIC MUSCLES. .
FLEXORFLEXOR, A MUSCLE THAT BENDS A , A MUSCLE THAT BENDS A JOINT. JOINT.
EXTENSOREXTENSOR, A MUSCLE THAT , A MUSCLE THAT STRAIGHTENS A JOINT.STRAIGHTENS A JOINT.
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A.A. When the BICEPS CONTRACTS, it When the BICEPS CONTRACTS, it FLEXES FLEXES the elbow jointthe elbow joint
B. When the TRICEPS CONTRACTS, it B. When the TRICEPS CONTRACTS, it EXTENDSEXTENDS the elbow joint the elbow joint
C. A controlled movement requires C. A controlled movement requires contraction by both muscles.contraction by both muscles.
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SMOOTH MUSCLESMOOTH MUSCLE• Smooth muscle cell are small• Not striated• Contract more slowly• Is under involuntary control. And they to
function as a unit and contract at the same time. e.g intestine
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CARDIAC MUSCLECARDIAC MUSCLE
• Share some characteristic with both smooth and skeletal muscle
• Is under involuntary control and are influenced by hormon
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Thank you Questions please
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