APBI 311 - Skeletal System Flashcards
Define Osteology
Study of bones that collectively make up the skeletal system
General functions of the skeletal system (5)
1) Protection
- CNS protected by skull and vertebrate
- Heart & lunges protected by rib cage and sternum
- Internal urogenital protected by pelvis.
2) Support
- Body form and rigidity
3) Leverage
- locomotion, defence, grasping, etc
4) Storage
- Mineral (calcium and phosphorus deposits)
5) Hematopoiesis
- Blood cell formation.
Cortical Bone - Form and function
aka Compact Bone
Form: hard layer of bone, covers most bones
Function: resist bending, protects spongy bones.
Cancellous Bones - form and function
Aka Spongy Bone
Form: composed of many spicules and forms porous network. Located in epiphysis, metaphysis, and directly outside medullary cavity.
Function: cushions stresses, filled with hematopoietic cells.
Define epiphysis, diaphysis, and metaphysis.
Epiphysis - either extremity of LONG bones
Diaphysis - shaft between two epiphysis of LONG bones.
Metaphysis - most newly formed bone and one either end of diaphysis. Filled with SPONGY bone.
Contrast epiphysis cartilage and articular cartilage.
Epiphysis cartilage - layers of hyaline cartilage separating the epiphysis and diaphysis of an immature bone - site of bone growth
Articular Cartilage- thin layer of hyaline cartilage that covers articular surface of bone
Types of Articular Projections (4)
Head - spherical projection (head of femur)
Condyle - cylindrical/round process on the ends of bones that articulates.
Trochlea - pulley like mass (two masses and the groove in the middle)
Facet - flat smooth surface of bone. Generally an articular surface.
Non-Articular Projections (2)
Process - a bony projection like something on the vertebrae
Tuberosity - non-articular projection for the attachment of ligaments, muscles, tendons etc. enlarged or formed by muscle stress during bone growth.
Non-articular Depressions (4)
1) Fossa -large non-articular shallow or hollow depression
2) Fovea - small non-articular depression
3) Foramen - hole through which nerves or blood vessels pass through.
4) Canal - hole through 2 or more bones.
Articular Depressions (3)
1) Glenoid Cavity - shallow articular cavity like in scapula
2) Cotyloid Cavity - deep articular cavity like in hip.
3) Notch - Articular indentation like the notch in the ulna.
Bone types (5)
1) long bones
2) short bones
3) flat bones
4) sesamoid bones
5) pneumatic bones.
Long Bones - form, function, and examples
Form: longer in one dimension, grows in length at epiphysial cartilage.
Function: longer leaver, reach, support, locomotion,etc.
Examples: ulna, radius, humerus, femur, tibia, fibula, metacarpals
Short Bones - form, function, and examples
Form: equal in all dimensions, marrow filled interior, located in complex joints
Function: shock absorbers, blood cell genesis, allow movement, elasticity, etc.
Examples: carpals and tarsals
Flat bones - form, function, and examples
Form: thin, expanded in two directions, two layers of cortical bone with cancellous bone in between.
Function: protect vital organs, provides attachment site for muscles.
Examples: ribs, ilium, sternum, scapula.
Sesamoid Bones - form, function, and examples
Form: sesame seed like, short bone embedded WITHIN tendon or joint capsule.
Function: alter the insertion point of muscles.
Examples: patella (knee cap)
Pneumatic Bones - form, function, and examples
Form: bones that contain air spaces or sinuses
Function: communicate to external environment air.
Examples: Frontal bones and maxillary bones of the skull.
Parts of axial skeleton (5)
Skull, vertebral column, sternum, ribs, tail
Skull - function
1) PROTECTS THE BRAIN
2) Supports many sense organs
3) Forms passages for the beginning of digestive system, and respiratory system.
Vertebral column - form
Median, unpaired, irregular bones, regionalized to different areas (cervical, thoracic, lumbar, sacral, caudal)
C, T, L, S, LS, CD of vertebral column
Cervical - neck region Thoracic - chest region Lumbar - gut region Sacral -pelvic region Lumbar-sacral (synsacral) region ONLY IN BIRDS Caudal - tail region
Vertebral formula - humans and cows
Humans - C7- T12 - L5 - S5 - CD4
(7-12-5-5-4)
Cows - C7 - T13 - L6 - S5 - CD 18-20
(7-13-6-5-18/20)
Sternum and ribs - function
Sternum - floor of bony thorax, attachment site for coastal cartilages of true ribs, origin of pectoral muscles
Rib - origin for some muscles, protect viscera.
Parts of Appendicular Skeleton
1) Pectoral limbs and scapula
2) pelvic limbs and pelvic limbs
Composition of Bones
2/3 inorganic in framework of organic
- inorganic brittle but strong
- organic very flexible.
Ossification - define and process
Definition: process of bone formation
Process: osteoblasts lays down ostoid tissue, calcified by due to phosphatase influence.
Define “centre of ossification”
Localized area of bone formation.
Types of Ossification (3)
1) Heteroplastic Ossification
2) Intramembranous Ossification
3) Endochondral (intracartilagenous) Ossification.
Heteroplastic Ossification: Define and Examples
Definition: Bone formation in tissue other than the skeleton.
Example: animal penises, bovine heart, etc.
Define “Intramembranous Ossification”
Definition: Ossification that occurs between sheet-like layers of connective tissues.
Intramembranous Ossification Process
1) Connective tissue cells differentiate into osteoblasts which form spongy bones
2) Osteoblasts become osteocytes when bony matrix completely surrounds them.
3) Connective Tissue on the surface of each developing structure forms a periosteum.
4) Osteoblasts inside periosteum cover spongy bone.
Define “Endochondral Ossification”
The bone is preformed in cartilage and is later mineralized and replaced by bone tissue.
Growth of Endochondral Bone
1) Bone growth in length at epiphyseal plates at metaphysis.
2) Cartilage cell multiplication in zone of growth will force the epiphysis away from the diaphysis, lengthening epiphyseal plate.
3) Removal of cartilage and deposition of bone in zone of ossification leads to lengthening of diaphysis.
4) Diameter increase is due to activity of osteogenic layer of the periosteum.
Regions of Epiphyseal Plates (3)
1) Zone of growth
2) Zone of cartilage formation
3) Zone of ossification
Bone Matrix of Oseoid Tissue
1) Sensitive to environmental changes
2) Decrease and Increase in size
3) Capable of withstanding tension, compression, bending, and torsion.
Define “Fracture”
A break in the continuity of bones
Types of Fracture (5)
1) Simple - Skin over fracture site unbroken
2) Green Stick - One side of bone broke, the other is intact.
3) Compound - Exterior wound contacts bone (or bone protrudes).
4) Epiphyseal - Fracture at the junction of epiphysis and diaphysis
5) Comminuted - Small number of fragments formed.
Fracture Healing
1) Vascular damage initiates repair sequence.
2) Specialized repair tissue binds ends of fracture together
3) Blood clot forms immediately and is reabsorbed and replaced by callus
4) Callus is mineralized
5) Reorganization of callus and formation of bone shaft in marrow cavity.
Phases of fracture healing (4)
1) Hemorrhage phase
2) Early Healing Phase (Inflammatory response)
3) Reparative phase (Well formed callus)
4) Remodelling phase (cortex remodelling)
Pathological bone conditions (5)
1) Tuberculosis - bacterial infection
2) Osteomylitis - inflammation of bones and marrow
3) Osteoma - Bone tumour
4) Rickets
5) Achondroplasia (Dwarfism).
Define “Joints”
Articulation between bones.
Define “arthrology”
Study of Joints
Functions of Joints (4)
1) Bind parts of the skeletal system together
2) Make possible bone growth
3) Permit parts of the skeleton to change shape during childbirth
4) Enable the body to move in response to the skeletal muscle contractions.
Types of Joints in terms of movement (3)
1) Synarthrotic - Immovable
2) Amphiarthrotic - slightly movable
3) Diarthrotic - Freely movable (articular cartilage, joint capsule and synovial membrane)
Types of Joints in terms of tissue type binding (3)
1) Fibrous Joints - United by fibrous tissue, no joint cavity. (e.g. bones of skull, teath in their sockets.)
2) Cartilaginous: No joint cavity, united by cartilage. (e.g. adjacent pelvic bones)
3) Synovial (Diarthrodial): Surrounded by thick flexile membrane forming a sac into which is secreted thick viscous fluid that lubricates the joint. Has articular surfaces, cartilages, and cavities. Has joint capsule and ligaments.
Structure of Synovial Joint (8)
1) Articular Cartilage
2) Subchondral plate
3) Joint Capsule
4) Synovial membrane
5) Synovial Cavity
6) Synovial fluid
7) Menisci
8) Bursae
Articular Cartilage
Resists wear and minimizes friction when compressed as joint moves.
Subchondral Plate
Bone beneath the articular cartilage and absorbs shock.
Joint Capsule
Outer fibrous tissue that binds the articular ends of bones together
Synovial Membral
Inner layer of joint capsule of loose tissue that secretes and resorbs fluids.
Synovial Cavity
Closed sack surrounded by synovial membrane.
Synovial Fluid
Moistens and lubricates and supplies nutrients to the articular cartilage.
Menisci
Disks of fibrocartilage between articular surfaces that absorb shock and provide cushion.
Bursae
Closed fluid filled sacs.
Types of Joint Movements (4)
1) Gliding
2) Angular
3) Rotation
4) Circumduction
Gliding Movement
Simplest type of movement, just surface moving over another without angular or rotary motion.
Angular Movement and types (5)
Angular motion increases or decreases angles between two adjoining bones.
1) Flexion - Decrease angles
2) Extension - Increase Angles
3) Hyper extension increase beyond straight line.
4) Abduction - Moving away from body
5) Adduction - bringing toward the body.
Rotation movement
Movement around point without displacement (E.g. head)
Circumduction
Movement of hips and shoulders
Pronation
Turning downwards
Supination
Turning Upwards
Eversion
Turning outwards
Inversion
Turning inwards
Skull Joints (3)
1) Suture - which ossifies with age
2) Symphysis of mandible
3) Sychondrosis - junction of sphenoid and occipital bone at base of skull
Injuries and Disorders of Joints (6)
1) Dislocation - Stretching or tearing of ligaments, tearing of joint capsule
2) Subluxation - Bones move out of place and irritate nerves
3) Arthritis - Inflammation of joints
4) Joint Fractures
5) Thoroughpin - inflammation within a tendon sheath. (Tenosynovitis)
6) Laminitis - Inflammation of digital laminae near the hoof.
