What makes up the Axial Skeleton (80 Bones)
The axial skeleton supports the head, neck, back, and chest and thus forms the vertical axis of the body.
It consists of the skull, vertebral column; the sacrum, coccyx, The thoracic cage; ribs and sternum.
What makes up the appendicular skeleton ( 126)
It is joined by a multitude of joints, ligaments, and cartilage, form the appendicular skeleton.
This allows for greater motion and movement when compared to the axial skeleton.
The appendicular skeleton bones are vital for movement, locomotion, and overall function of the human body
- Shoulder Girdle; Clavicle, Scapula
- Upper Limbs; Humerus, Radius, Ulna, Carpals, Metacarpals, Phalanges
- Lower Girdle; Femur, Tibia, Fibula, Tarsals,Metatarsals, Phalanges, Calcaneus (heel) - Subtalar Joint
- Pelvic Girdle; The coxal bone (hip bone, pelvic bone) is a large, flattened, irregularly shaped bone, constricted in the center and expanded above and below.
Pelvis, Pubis Symphysis
How many bones in body - where
When Born = 270 - 300 bones
At 25 bones completely fuse into larger bones = 206 bones
Axial Skeleton = 80 bones
- Skull 29
- Vertebral Column 26
- Thorax 25
- Ossicles 6
Appendicular Skeleton = 126 Bones
- Shoulder Girdle 4
- upper limb 60
- pelvic girdle 2
- lower limb 60
What are the main functions of the bone?
- Frame and support; provides a firm framework that gives shape and support to the body parts.
- prevents soft tissue from collapsing in a heap
- provides points of attachment for most muscles in the body - Movement; bones act as an anchor for muscles to attach to so that the body can move.
- Protection of Vital organs; bone making up Skelton is hard structures encasing vital organs so that bones receive the main force/harm first before organs, spinal chord ect.
- Storage organs; for minerals (salts) and fats
Minerals stored; K, Na, Ca, P
These can be distributed to other regions of the circulatory system when required Eg. Preggo has no Ca, it can be removed from skeleton bones for foetus growth - Blood cell production; Red marrow within bones has stem cells that can differentiate into blood cells. Factors in cells environment determines whether they become RBC, WBC or platelets
What is the Periosteum
The periosteum is a dense, white, fibrous membrane covering the outer surface of bone
- no periosteum at joints where bones are covered with articulations cartilage
A typical long bone consist of Diaphysis and Epiphysis, what are they?
Diaphysis - a shaft making up most the bone
Epiphysis - the ENDS; enlarged ends of the bone with a thin layer of articular cartilage
When bone is cut lengthwise, explain what is seen.
Diaphysis is seen to be hollow cylindrical COMPACT BONE surrounding the cavity.
This cavity is used as fat storage site = Yellow bone marrow cavity
Epiphysis has compact bone on the outside but the central regions contain SPONGY/ CANCELLOUS bone.
Certain bones here have RBC production RED BONE MARROW
What is bone
Bone is a connective tissue (hardest connective tissue)
- consists of cells separated from each other by larger amounts of non cellular material called a matrix
Cells + matrix = bone
A bone is rigid + strong in strength because of inorganic salts deposited in Matrix
Has brittle and calcified matrix (Calcium phosphate) with many collagen fibres, giving bones a degree of Pliability (flexibility)
3 types of cells occur in bones
What is the medullary cavity
It is the cavity found in long bones filled with yellow bone marrow ( stores fat - energy)
What are the three types of cells found in Bones
- Osteoblasts (for building bones)
- young cell that produces bone
- forms bone matrix; calcium phosphate + collagen fibres = rigid bone - Osteocytes
- bone cells formed from osteoblasts
- mature bone cells embedded or trapped in matrix
- maintains bone tissue/ matrix - Osteoclasts ( bone breaking)
- Reabsorbs (destroys) bone tissue
- makes acidic environment to dissolve bone ( makes cavities)
- active during growth or healing or ageing
What is the structure of a compact bone?
Compact bone is a very hard bone which runs vertically along the length of the long bone to provide strength
It is made up of Osteons or Haverison systems
What are Haversion systems?
Bone is Made up of round units called OSTEONS/ Haveriosn systems
- are circular layers of bone ( LAMELLAE) surrounding central HAVERSION CANAL which carries Blood, Lymph vessels and Nerves
- small spaces in Matrix are called LACUNAE, bone cell (OSTEOCYTES) occupies each lacunae
- tiny canals = canaliculi, runs between the lacunae
- cytoplasmic projections from bone cell all go into canaliculi - so adjacent cells can connect
Bone cells + Blood vessels = haverison systems/ Osteon
What is the structure of spongy bone?
- found in epiphysis region of long bone
- have no haversion systems
- TRABECULAE= irregular arrangement of thin bony parts
- osteocytes in trabeculae
- blood vessels, lymph vessels and nerves are found
- in adults= bone marrow confined to these cavities
Epipseal line of cartilage - remnant of plate seen in young growing bones.
Trabeculae + small spaces (containing bone marrow - red) + B.V
What is ossification?
Bones of the skeleton are formed from hyaline cartilage ( in embryo) by a process of ossification (bone formation) and they grow by bone remodelling.
From 8wks - birth = bony skeleton
Bone remodelling is also important in bone repair/ fractures
List the three types of cartilage
- Hyaline
- Elastic
- Fibro - cartilage
What is cartilage
Cartilage is a type of connective tissue with no blood vessels
Contains numerous fibres made of a protein called collagen
Protein fibres are embedded in firm matrix of protein - carbohydrate Complex called CHONDRIN
Nutrition and wastes removal for cells = via diffusion through matrix ( slow process)
Chondrocytes - have slow metabolism, slow cell division = slow healing
Osteoporosis (Porous Bone)
It is the loss of bone mass that occurs with ageing becomes sufficient to impair normal functioning.
Causes
- bone disease
- bone loose minerals
- Ca or vitamin D deficiency
- bone breakdown
- bone density decreases wearing bone ( thin, weak, brittle, fragile)
- post menopausal women ( decrease in oestrogen)
- inactivity
Symptoms
- no symptoms till bone break
- bones WEAK and Thin = increase chance of breaking/ fracture
Common places; Spine, Wrist and Hip
Effects
- loss of height
- hunching of spine (curved) deformed wrist and hips
Osteoporosis
- dietary supplements calcium, vit D
- healthy diet
- weight bearing exercise
- lifestyle changes
- stop smoking
Risk factors
- family/ genetic history
- poor diet
- lack of exercise
- being female - menopause, sharp drop in oestrogen hormone
- men - low testosterone ( gradual decrease) and GH
- lifestyle; smoking and alcohol
Diagnosis
- bone density scan
Osteoarthritis (joints)
It is the gradual change in the joints that occur over time and is frequently associated with ageing
Causes
- Loss/ wearing away of cartilage joints
- wearing of bone - bare bones grate against each other
- occupations requiring repetitive use of joint
- previous joint injury
- overweight
Symptoms
- pain and stiffness in joints
- restricted/ difficult movement, loss of joint function
- inflammation ( increased blood supply, increased WBC)
- swelling of joints
- Bony SPURS (growths) develop
Effects
- abnormal bone formation
- deformities of hands and feet
- bony spurs
Treatment
- no cure
- pain relief medication
- anti-inflammatory drugs
- physiotherapist to strengthen muscles
- gentle exercise program
- weight loss program
- joint replacement surgery or realignment
Risk factors
- family history
- repetitive moments or strains
- overweight
- joint injury
Found in bearing joints ; spine, knee, foot, hips
Diagnosis
- X ray
What is the microscopic structure of cartilage?
Has firm matrix with collagen fibres embedded
- within the matrix are spaces that contain the cartilage cells called CHONDROBLASTS
Chondroblasts produce matrix and gradually become surrounded by it until they are trapped in small spaces called lacunae
- once this occurs the cells are considered to be mature and referred to as CHONDROCYTES
The collagen fibres in the matrix range in thickness from extremely fine to quite coarse. This variation allows classification into three types.
What is the Perichondrium?
It is the fibrous membrane of connective tissue that covers the external surface of cartilage
* except articular cartilage found in joint end of bones
Blood supply to cartilage comes from blood vessels located in the inner layers of perichondrium
What are the three types of cartilage? Characteristics and location .
- HYALINE CARTILAGE
- contains closely packed fine fibres ( collagenous) in the matrix
- There are chondrocytes in lacunae
- gives cartilage strength and flexibility
FOUND IN THE RINGS OF TYE TRACHEA, BRONCHI AND THE ENDS OF BONES ( articular) - ELASTIC CARTILAGE
- has elastic fibres and collagen fibres (but as closely packed)
- this cartilage provides support in places (external ear) and is also flexible
- springing meaning it can fold down and go back up
FOUND IN EAR - FIBROCARTILAGE
- it has coarse appearance from the parallel bundles of thick collagenous fibres
- not as compact as in hyaline therefore it is able to be COMPRESSED slightly
- supports the weight of the body, and can withstand heavy pressure
FOUND IN THE INTERVEGRAL DISC OF SPINAL CHORD
ARTICULAR CARTILAGE OF KNEE JOINT (disc)
PUBIS SYMPHYSIS CONNECTING PUBIC PELIV BONES
What are joints?
The site at which two or more bones come together or articular is called a joint.
A joint contains
- collagen,ligaments (B-B), Tendons (M-B), synovial fluid and cartilage
Bones are classified via the function and structure
What are the three types of joints and their characteristics ?
Fibrous/ Fixed/ Immoveable Joints
- the bones are held in place by fibrous connective tissue
- difficult to damage as it is so strong that the bone is usually broken before joint
FOUND IN SUTURES OF SKULL, JOINT BETWEEN TEETH IN JAWS
Cartilaginous / Slightly moveable
- joint in held in place by cartilage which allows slight movement to occur
- PUBIC SYMPHYSIS between two pelvic bones, JOINTS BETWEEN ADJACENT VERTEBRAE, RIBS AND STERNUM
Synovial or freely moveable joints
- feels moveable but the amount is limited by ligaments, tendons, muscles and adjoining bones.
OCCURS AT SHOULDER, ELBOW, WRISTS, FINGERS, HIP, KNEES, ANKLES AND TOES
- there are six types
List the six types of synovial joints in the body
- ball and socket joints
- hinge joints
- pivot joints
- gliding joints
- saddle joint
- condyloid or ellipsoid joints
