Skeletal System Flashcards
Types of Joints
- Fibrous/fixed
- Synovial/Freely movable
- Cartilaginous/ Slightly moveable
Types of Synovial joints
- Ball and socket
- Saddle
- Pivot
- Gliding
- Condyloid
Define Articulation
Site where 2 or more bones meet
Fundamental Functions of joints
- Allow the skeleton to have mobility
- Hold skeleton together
Gliding Joint
- Articular surfaces are essentially flat
- Allow only slipping or gliding movements
- Found between carpal bones, tarsal bones, the sternum and clavicle, the scapula and clavicle
Hinge Joint
- Cylindrical projection of one bone fits into a trough-shaped bone on another
- Motion is along a single plane, resembles action of a hinge
- Uniaxial joint only permits flexion and extension
Examples: - Knee
- Elbows
- Phalanges
Pivot Joint
Rounded end of one bone protrudes into “sleeve” or ring, composed of bone or ligaments of another bone
Examples:
- Between the radius and ulna
- Between first and second vertebrae
Condyloid Joint
- Oval articular surface of one bone fits into a complementary depression in another
- Both articular surfaces are oval
- Biaxial joints permit all angular motions
Examples: - Radius and carpal bones
- First Phalange and metacarpals
Saddle Joint
- Similar to condyloid joint but allow greater movement
- Each articular surface has both a concave and a convex surface
Examples:
-Thumb
Ball and Socket Joint
- A spherical or hemispherical head of one bone articulates with a cuplike socket of another
- Universal movements (in all planes and axes, including rotation)
Examples: - Shoulder blade
- Humerus
Division of skeleton
axial skeleton - skull, spinal column, sacrum, ribs and sternum
Appendicular skeleton - clavicle, scapula, Humerus, ulna, radius, carpals, metacarpals, phalanges, pelvis, femur, patella, fibular, tarsals, metatarsals
Microscopic bone structure
- Compact/dense bone
- Spongy bone
- Epiphysis
- Bone matrix
Compact bone
Hard outer shell - makes up diaphysis
Spongy bone
A mixture of small bone pieces and red bone marrow
- Composed of trabeculae
- Penetrated by blood vessels from the periosteum
Yellow bone marrow
Found in the centre of the diaphysis - stores fat
Epiphysis
Shaft of the bone epiphyseal line - site of growth
Bone matrix
- Non-cellular material that separates connective tissue
- Contains inorganic salts increasing strength and rigidity
What are joints?
- Any site at which 2 or more bones join together
- May or may not permit movement
- Classified according to structure and function
Function of the skeleton
- Shape and support body
- Storage of minerals and fats
- Permit flexible body movement
- Protection of vital organs
- Blood cell production
Synovial structures
- Fibrous capsule
- Synovial membrane
- Synovial fluid
- Articular cartilage
- Articular discs (menisci)
- Bursae
- Accessory ligaments
Fibrous capsule
- Consists of dense, fibrous connective tissue connected to the periosteum of the articulating bones - Flexibility allows movement
- Strength stops dislocation
- Structure that holds bones together
Synovial membrane
- Makes up the inner layer of the capsule
- Loose connective tissue, well supplied with capillaries
- Lines the entire joint; except articular cartilage and disc
Synovial fluid
- Lubricates and provides nourishment for cells
- Reduces friction
- Consists of phagocytes
- Clears debris
- Secreted by synovial membrane
Articular cartilage
- Covers the articulating surfaces of the bones forming the joint
- Provides a smooth surface for movement
Bursae
- Sacks of synovial fluid
- Prevents friction between a bone and ligament, tendon or skin
Accessory ligament
Holds bones together
Joint movement
Adduction - away from the midline
Abduction - towards the midline
Extension - increasing the angle between articulating bones
Flexion - decreasing the angle between articulating bones
Rotation - Movement of bone along its long axis
Articular discs (menisci)
- Occurs in some synovial joints
- In the knee there is menisci consisting of fibrocartilage extending inward from the articular capsule
Cartilage
- Type of connective tissue
- Contains collagen fibres (protein)
- Collagen is embedded in chondrin, a protein-carbohydrate matrix
- The fibres give flexibility, matrix provides strength
Where can cartilage be found
Between 2 bones Examples: - Synthesis Pubis - Cartilage discs (vertebrae) - Arms and legs (between long bone)
Chondroblasts
Produce the matrix that makes up cartilage
Chondrocytes
- Mature cartilage
- Occurs when chondroblasts are trapped in small spaces called lacunae
Types of cartilage
- Hyaline
- Elastic
- Fibrocartilage
Hyaline cartilage
- Closely packed fine fibres
- Strength and flexibility
- Found in trachea and bronchi and articulated joints
Elastic cartilage
- Elastic fibres and fine collagenous fibres
- Not as densely packed as hyaline cartilage
- Found in external ear
Fibrocartilage
- Thick fibres and not densely packed
- Compression possible
- Found in intervertebral discs, knee joint and symphysis pubis
Perichondrium
- A fibrous membrane of connective tissue that covers cartilage
- Blood supply to cartilage is found here
- Nutrients and wastes must travel slowly by diffusion through the matrix as there are no blood vessels in the cartilage.
