BONE & FUNCTIONS OF BONE & FUNCTIONS OF SKELETAL SYSTEMSKELETAL SYSTEM

ByBy

Dr Muhammad Altaf HussainDr Muhammad Altaf Hussain

Lecturer Anatomy SMC Lecturer Anatomy SMC (DUHS)(DUHS)

ObjectivesObjectives To know the division and functions of the To know the division and functions of the

skeletal system.skeletal system.

To understand the methods to classify the To understand the methods to classify the bones.bones.

To discuss the different ways to classify To discuss the different ways to classify the bones.the bones.

To Identify the gross structures of the adult To Identify the gross structures of the adult and young long bones.and young long bones.

IntroductionIntroduction

What is Bone?What is Bone? rigid connective tissue that makes up the rigid connective tissue that makes up the

skeleton of vertebrates.skeleton of vertebrates. Ct 1/3Ct 1/3rd,rd, impregnated with calcium salts 2/3 impregnated with calcium salts 2/3rdrd . . Hardness and rigidity is mainly due to the Hardness and rigidity is mainly due to the

presence of calcium phosphate , partly from presence of calcium phosphate , partly from calcium carbonate, & traces of other salts.calcium carbonate, & traces of other salts.

Flexibility is because of organic CT ie collagen Flexibility is because of organic CT ie collagen fibres.fibres.

Highly vascular .Highly vascular . Greater regenerative power .Greater regenerative power . It can show atrophy & hypertrophy.It can show atrophy & hypertrophy.

Functions of BoneFunctions of Bone

Mechanical Mechanical protection , shape , protection , shape , movementsmovements..

Synthetic Synthetic haematopoiesis Metabolic Metabolic storage , storage ,

detoxificationdetoxification.. It also givesIt also gives immune response immune response..

Table. 6.2

CLASSIFICATION of CLASSIFICATION of BONES BONES • According to shapeAccording to shape

1.1. long boneslong bones = length is greater than = length is greater than breadthbreadth

= consists of shaft (diaphysis) & = consists of shaft (diaphysis) &

two extremities (epiphysis)two extremities (epiphysis)

diaphysis diaphysis = filled with yellow marrow = filled with yellow marrow= cylindrical, large space or canal = cylindrical, large space or canal

at the centerat the center = periosteum= periosteum

epiphysis epiphysis = made up of cancellous tissue = made up of cancellous tissue

e.g.: femur, humerus, tibia, fibula, radius, ulna, e.g.: femur, humerus, tibia, fibula, radius, ulna, phalanges phalanges

MembranesMembranes: : 1. periosteum1. periosteum2. endosteum2. endosteum

CLASSIFICATION of CLASSIFICATION of BONESBONES cont’n.cont’n.• According to shapeAccording to shape2. 2. short bonesshort bones = cuboidal in = cuboidal in

shapeshape= spongy bone with thin = spongy bone with thin coat of compact bone.coat of compact bone.e.g.: carpals (wrist), tarsal e.g.: carpals (wrist), tarsal (ankle) bones(ankle) bones

3. flat bones3. flat bones = broad or = broad or elongated flat plateselongated flat plates= for protection & muscle = for protection & muscle attachmentsattachmentscomposition: 2 thin layers composition: 2 thin layers of compact tissues. of compact tissues. Enclosing a thin layer of Enclosing a thin layer of spongy bone.spongy bone.e.g.: bones of the skull, e.g.: bones of the skull, sternum, ribs, scapulasternum, ribs, scapula

CLASSIFICATION of CLASSIFICATION of BONESBONES 4 Irregular bones4 Irregular bones

5 pneumatic bones5 pneumatic bones

6 sesamoid bones6 sesamoid bones

7 accessory bones.7 accessory bones.

CLASSIFICATION of CLASSIFICATION of BONESBONES

Regional Regional classification:classification:

1.1. axial skeleton.axial skeleton.

1.1. Appendicular Appendicular skeleton.skeleton.

Bone growthBone growth The increases in the length of the bone is The increases in the length of the bone is

due to growth plates made of cartilagedue to growth plates made of cartilage Cartilage is continually formed and Cartilage is continually formed and

turned into bone (ossified)turned into bone (ossified) The growth plate ceases to function when The growth plate ceases to function when

the person becomes an adult.the person becomes an adult.

The location of growth plates in a boneThe location of growth plates in a bone

CLASSIFICATION of CLASSIFICATION of BONESBONES

According to development According to development 1) membrane (dermal) bone.1) membrane (dermal) bone.

2) cartilaginous bones.2) cartilaginous bones.

3) membrano-cartilaginous bones.3) membrano-cartilaginous bones.

CLASSIFICATION of CLASSIFICATION of BONESBONES Structural classification:-Structural classification:-

Macroscopically;Macroscopically;

1.1. Compact bone.Compact bone.

2.2. Cancellous spongy or trabecular bone.Cancellous spongy or trabecular bone. Microscopically;Microscopically;

1.1. Lamellar bone.Lamellar bone.

2.2. Fibrous bone.Fibrous bone.

3.3. Dentine bone.Dentine bone.

4.4. Cement.Cement.

To be continued in next class

THANK YOU

young and adult long bone

Blood Supply of Long Blood Supply of Long BoneBone

Nutrient Nutrient artery.artery.

Periosteal Periosteal arteries.arteries.

Epiphysial Epiphysial arteries.arteries.

Metaphysial Metaphysial arteries.arteries.

Blood Supply of Long Blood Supply of Long BoneBone

RadiographsRadiographs

IntroductionIntroduction

Skeleton :- Skeleton :- The The human human skeletonskeleton consists of both fused and consists of both fused and individual individual bones supported and supported and supplemented by ligaments, tendons, supplemented by ligaments, tendons, muscles and cartilage. It serves as a muscles and cartilage. It serves as a scaffold which supports organs, anchors scaffold which supports organs, anchors muscles, and protects organs such as the muscles, and protects organs such as the brain, lungs and heart. The biggest bone in brain, lungs and heart. The biggest bone in the body is the femur and the smallest is the body is the femur and the smallest is the stapes bone in the middle ear. In an the stapes bone in the middle ear. In an adult, the skeleton comprises around 14% adult, the skeleton comprises around 14% of the total body weight,of the total body weight,[1][1] and half of this and half of this weight is water.weight is water.

Fused bones include those of the pelvis and Fused bones include those of the pelvis and the cranium. Not all bones are the cranium. Not all bones are interconnected directly: There are three interconnected directly: There are three bones in each middle ear called the ossicles bones in each middle ear called the ossicles that articulate only with each other. The that articulate only with each other. The hyoid bone, which is located in the neck and hyoid bone, which is located in the neck and serves as the point of attachment for the serves as the point of attachment for the tongue, does not articulate with any other tongue, does not articulate with any other bones in the body, being supported by bones in the body, being supported by muscles and ligaments.muscles and ligaments.

Bones have eleven main functions:Bones have eleven main functions: [[edit] Mechanical] Mechanical Protection — Bones can serve to protect internal organs, such as the Protection — Bones can serve to protect internal organs, such as the skull protecting the protecting the brain or the or the ribs

protecting the protecting the heart and and lungs. . Shape — Bones provide a frame to keep the body supported. Shape — Bones provide a frame to keep the body supported. Movement — Bones, Movement — Bones, skeletal muscles, , tendons, , ligaments and and joints function together to generate and transfer function together to generate and transfer

forces so that individual body parts or the whole body can be manipulated in three-dimensional space. The forces so that individual body parts or the whole body can be manipulated in three-dimensional space. The interaction between bone and muscle is studied in interaction between bone and muscle is studied in biomechanics. .

Sound transduction — Bones are important in the mechanical aspect of overshadowed Sound transduction — Bones are important in the mechanical aspect of overshadowed hearing. . [[edit] Synthetic] Synthetic Blood production — The Blood production — The marrow, located within the , located within the medullary cavity of long bones and interstices of cancellous of long bones and interstices of cancellous

bone, produces blood cells in a process called bone, produces blood cells in a process called haematopoiesis. . [[edit] Metabolic] Metabolic Mineral storage — Bones act as reserves of minerals important for the body, most notably Mineral storage — Bones act as reserves of minerals important for the body, most notably calcium and and

phosphorus. . Growth factor storage — Mineralized bone matrix stores important growth factors such as insulin-like growth Growth factor storage — Mineralized bone matrix stores important growth factors such as insulin-like growth

factors, transforming growth factor, bone morphogenetic proteins and others. factors, transforming growth factor, bone morphogenetic proteins and others. Fat Storage — The yellow bone marrow acts as a storage reserve of fatty acids Fat Storage — The yellow bone marrow acts as a storage reserve of fatty acids Acid-base balance — Bone buffers the blood against excessive pH changes by absorbing or releasing alkaline Acid-base balance — Bone buffers the blood against excessive pH changes by absorbing or releasing alkaline

salts. salts. Detoxification — Bone tissues can also store Detoxification — Bone tissues can also store heavy metals and other foreign elements, removing them from the and other foreign elements, removing them from the

blood and reducing their effects on other tissues. These can later be gradually released for excretion.blood and reducing their effects on other tissues. These can later be gradually released for excretion.[[citation needed]] Endocrine organ - Bone controls phosphate metabolism by releasing fibroblast growth factor - 23 (FGF-23), Endocrine organ - Bone controls phosphate metabolism by releasing fibroblast growth factor - 23 (FGF-23),

which acts on kidney to reduce phosphate reabsorption. which acts on kidney to reduce phosphate reabsorption.

The skeleton and The skeleton and musclesmuscles

The Human SkeletonThe Human Skeleton

Functions of the skeletonFunctions of the skeleton

Frame workFrame work ShapeShape ProtectionProtection MovementMovement Manufacture of Manufacture of

blood cellsblood cells

The Human SkeletonThe Human Skeleton

Parts of the axial skeletonParts of the axial skeleton Consists of Consists of

the skull, the skull, vertebrae, vertebrae, ribs and ribs and sternumsternum

Lesson objectivesLesson objectivesBy the end of this lesson you should be able to:By the end of this lesson you should be able to:

Describe the macroscopic anatomy of a long Describe the macroscopic anatomy of a long bone: medullary cavity, compact bone, spongy bone: medullary cavity, compact bone, spongy bone, and cartilage.bone, and cartilage.

Describe the function of the following: cartilage, Describe the function of the following: cartilage, compact bone, spongy bone (include red and compact bone, spongy bone (include red and yellow marrows).yellow marrows).

HIGHER LEVELHIGHER LEVEL Understand osteoblast role in bone growth. Understand osteoblast role in bone growth. Terminating development of adult height. Terminating development of adult height. Role of osteoblasts in bone cell replacement. Role of osteoblasts in bone cell replacement. Bone renewal. Bone renewal. Role of calcium in bone.Role of calcium in bone.

Bone growth (HL)Bone growth (HL) The increases in the length of the bone is The increases in the length of the bone is

due to growth plates made of cartilagedue to growth plates made of cartilage Cartilage is continually formed and Cartilage is continually formed and

turned into bone (ossified)turned into bone (ossified) The growth plate ceases to function when The growth plate ceases to function when

the person becomes and adultthe person becomes and adult

The location of growth plates in a boneThe location of growth plates in a bone

Types of boneTypes of bone

There are 3 types There are 3 types of boneof bone

1.1. Compact boneCompact bone

2.2. Spongy boneSpongy bone

3.3. Bone marrowBone marrow

Compact boneCompact bone Osteoblasts enclosed in Osteoblasts enclosed in

a matrixa matrix The matrix consists of The matrix consists of

70% inorganic salts 70% inorganic salts (such as calcium (such as calcium carbonate and carbonate and phosphate) and 30% phosphate) and 30% organic material (such organic material (such as the protein as the protein collagen)collagen)

Compact bone contains Compact bone contains blood vessels and blood vessels and nerve fibresnerve fibres

RibsRibs

12 pairs of ribs12 pairs of ribs Are attached to the Are attached to the

spinespine There are 3 types There are 3 types

of ribs depending of ribs depending on where they on where they attach to at the attach to at the front of the bodyfront of the body

Spongy boneSpongy bone

Found in the Found in the epiphyses epiphyses

Mixture of Mixture of compact bone with compact bone with pockets of bone pockets of bone marrow (looks like marrow (looks like aero chocolate)aero chocolate)

Spaces contain Spaces contain bone marrowbone marrow

Strength and Strength and rigidity but not rigidity but not heavyheavy

Bone marrowBone marrow

Medullary cavity Medullary cavity contains a soft fatty contains a soft fatty material called bone material called bone marrowmarrow

In young people bone In young people bone marrow is full of marrow is full of active red marrow active red marrow (makes blood (makes blood components)components)

Bone DeformationRickets can result from

insufficient vitamin D in the diet or from insufficient amounts of ultraviolet radiation from the sun. It can lead to skeletal deformation, such as vertebral or leg curvature.

Functions of the BonesFunctions of the Bones

1.1. SupportSupport2.2. ProtectionProtection3.3. MovementMovement4.4. StorageStorage5.5. HematopoiesisHematopoiesis

A stretching force (tension) pulling A stretching force (tension) pulling at both ends of a component or at both ends of a component or structure along its length.structure along its length.

Table. 6.1

2 Types of 2 Types of BoneBone

Compact boneCompact bone

Spongy boneSpongy bone

CLASSIFICATION of CLASSIFICATION of BONESBONES• According to structureAccording to structure

1. 1. compactcompact = solid mass; dense & hard = solid mass; dense & hard

= forms the outer layer of bone = forms the outer layer of bone structurestructure

= functional unit --- = functional unit --- Haversian systemHaversian system

2. 2. cancellous or spongycancellous or spongy = contain spaces = contain spaces filled with bone marrow filled with bone marrow

= incomplete = incomplete Haversian systemHaversian system

young and adult long bone

Blood Supply of Long Blood Supply of Long BoneBone

Nutrient artry.Nutrient artry. Periosteal arteries.Periosteal arteries. Epiphysial arteries.Epiphysial arteries. Metaphysial arteries.Metaphysial arteries.

CLASSIFICATION of CLASSIFICATION of BONES BONES • According to shapeAccording to shape1.1. long boneslong bones = length is greater than = length is greater than

breadthbreadth = consists of shaft (diaphysis) & = consists of shaft (diaphysis) &

two extremities (epiphysis)two extremities (epiphysis)

diaphysis diaphysis = filled with yellow marrow = filled with yellow marrow= = cylindrical, large space or canal at the cylindrical, large space or canal at the

centercenter

= = periosteumperiosteum

epiphysis epiphysis = made up of cancellous tissue = made up of cancellous tissue

e.g.: femur, humerus, tibia, fibula, radius, ulna, phalangese.g.: femur, humerus, tibia, fibula, radius, ulna, phalanges

MembranesMembranes: : 1. periosteum1. periosteum2. endosteum2. endosteum

CLASSIFICATION of CLASSIFICATION of BONES BONES cont’n.cont’n.• According to shapeAccording to shape

2. 2. short bonesshort bones = cuboidal in shape = cuboidal in shape

= spongy bone with thin coat of compact bone= spongy bone with thin coat of compact bone

= = sesamoid bonesesamoid bone -- short bone embedded in -- short bone embedded in aa

tendontendon e.g.: patellae.g.: patellae.g.: carpals (wrist), tarsal (ankle) bonese.g.: carpals (wrist), tarsal (ankle) bones

3. flat bones3. flat bones = broad or elongated flat plates = broad or elongated flat plates= for protection & muscle attachments= for protection & muscle attachments

composition: 2 thin layers of compact tse. enclosingcomposition: 2 thin layers of compact tse. enclosing

a thin layer of spongy bonea thin layer of spongy bone

e.g.: bones of the skull, sternum, ribs, scapulae.g.: bones of the skull, sternum, ribs, scapula

CLASSIFICATION of CLASSIFICATION of BONES BONES cont’n.cont’n.• According to shapeAccording to shape

4. Irregular bones4. Irregular bones = all other bones not = all other bones not assigned to the previous groupsassigned to the previous groups

e.g.: e.g.: vertebraevertebrae

pelvic bones pelvic bones

bones of the base of the skullbones of the base of the skull

CLASSIFICATION of CLASSIFICATION of BONES BONES cont’n.cont’n.• According to developmentAccording to development1. Membranous1. Membranous = = starts as fibrous membrane,starts as fibrous membrane,

calcium gradually deposited until structure calcium gradually deposited until structure

becomes ossified becomes ossified intramembranous intramembranous ossificationossification

e.g.: bones of the skull, mandiblee.g.: bones of the skull, mandible

2. Cartilagenous2. Cartilagenous = starts as cartilage, gradually = starts as cartilage, gradually ossifiedossified

enchondral or intracartilagenous ossification.enchondral or intracartilagenous ossification.

e.g.: long bonese.g.: long bones

CLASSIFICATION of CLASSIFICATION of BONES BONES cont’n.cont’n.• According to locationAccording to location

A X I A LA X I A L

skullskull 2222

hyoidhyoid 1 1

ossiclesossicles 6 6

vertebraevertebrae 2626

ribs & sternum ribs & sternum 25_ 25_

8080

CLASSIFICATION of CLASSIFICATION of BONES BONES cont’n.cont’n.• According to locationAccording to location

A X I A LA X I A L

skullskull 2222

hyoidhyoid 1 1

ossiclesossicles 6 6

vertebraevertebrae 2626

ribs & sternum ribs & sternum 25_ 25_

8080

CLASSIFICATION of CLASSIFICATION of BONES BONES cont’n.cont’n.• According to locationAccording to location

APPENDICULARAPPENDICULAR

Upper ExtremitiesUpper Extremities Lower ExtremitiesLower Extremitiesclavicleclavicle 22 hip bonehip bone 2 2

scapulaescapulae 22 femurfemur 2 2

humerushumerus 22 patellapatella 2 2

radiusradius 22 tibiatibia 2 2

ulnaulna 22 fibulafibula 2 2

carpalscarpals 16 16 tarsalstarsals 14 14

metacarpals 10metacarpals 10 metatarsals metatarsals 10 10

phalanges phalanges 28__ 28__ phalanges phalanges 28__ 28__

6464 62 62

Table. 6.2

MusclesMuscles

Involuntary Involuntary (smooth) muscle(smooth) muscle

Cardiac muscleCardiac muscle Voluntary Voluntary

( skeletal or ( skeletal or striped) musclestriped) muscle

The action of an antagonistic pair