Skeletal System Flashcards
What are the components of the skeletal system?
Bones, cartilage, tendons and ligaments
What is the composition of a bone?
50% water and 50% osseous tissue (solid, calcified material)
What are the functions of bones?
Function 1: Provide shape, support and framework to the body
Function 2: Protect internal organs
Function 3: Storage of minerals (e.g. salts, calcium, phosphorus)
Function 4: Hematopoiesis takes place in bone marrow
Function 5: Provide attachment to muscles
Function 6: Enable movement through articulation
What is the axial skeleton?
Forms the longitudinal part of the body
Made up of Skull, Vertebral Column and Bony Thorax
What is the appendicular skeleton?
- Limbs
- Pectoral girdle
- Pelvic girdle
How can bones be classified according to shape?
Long bones
Short bones
Flat bones
Irregular bones
Pneumatic bones
Sesamoid bones
What are the characteristics of long bones?
Length is more than width
Shaft and two ends
Have a medullary cavity
Nutrient foramina
E.g.. Femur, radius, ulna, humerus
What are the parts of a long bone?
Diaphysis
Epiphysis
Metaphysis
Growth plate
Medullary canal
Periosteum
Diaphysis
Shaft of the long bone which ossifies from primary center
Ossification = natural process of bone formation
Epiphysis
Ends of the bone which ossify from secondary center
Metaphysis
Area between epiphysis and diaphysis which is rich in blood vessels
Growth plate/epiphyseal plate of cartilage
Cartilage layer between metaphysis and epiphysis
Proliferation of cells in cartilage increases the length of a long bone
Medullary cavity
Cavity inside the diaphysis filled with bone marrow
What is the color of bone marrow?
Red bone marrow in children
Yellow bone marrow in adults
Periosteum
Covers the outer surface of long bones besides the articular surfaces
Articular cartilage
Articular cartilage covers articular surfaces
Which arteries supply the different regions of the long bone?
Nutrient artery: Supply the inner two thirds of the bone
Periosteal arteries: Supply the outer one thirds
Describe the course of the nutrient artery
Enters through nutrient foramen
Branches into ascending and descending branches which anastomose with metaphyseal & epiphyseal arteries
Further classifications of long bones
Miniature long bones: Have a shaft with one epiphyseal end. E.g. metacarpal and metatarsal bones.
Modified long bones: Horizontally placed. No medullary cavity. E.g. clavicle
What are the characteristics and examples of short bones?
No shaft
Small
Roughly cube shaped
E.g.: carpal & tarsal bones
What are the characteristics of flat bones?
Thin, flat and curved bones
E.g. skull, sternum and scapula
What is an irregular bone?
Bones which do not fit the bone categories
E.g. Vertebra, hip bone
What is a pneumatic bone?
Bone that contain air-filled spaces
E.g. frontal, sphenoid, ethmoid and maxilla
What is a sesamoid bone?
Developed & embedded in the tendons or muscles
Resemble a sesame seed
Allows the tendon to exert greater force
E.g.: patella
How long is the period of bone development?
Begins at the 6th week of embryo development and continues up to age of 25
How is the embryonic skeleton formed?
Made from fibrous membranes and hyaline cartilage
What are the types of ossification?
Intramembranous ossification: Bone develops from mesenchyme. E.g. flat bones of skull, mandible and clavicle
Endochondral ossification: Replacement of hyaline cartilage with bone. Forms most bones of the body
