Unit 2 - Musculoskeletal System Flashcards
Bones / The Skeleton
Serve(s) as the framework of the body
Supports and protects other tissues/organs
Aids in movement
Plays a role in the formation of blood cells
Stores fat & inorganic materials
Red bone marrow
Red blood cells
White blood cells
Clotting cells
Yellow bone marrow
Fat storage
Bone
Made up of osseous tissue
Two types: cortical and cancellous
Bone is living and always changing
Formation of bone (osteogenesis or ossification) begins prenatally and is completed at time of physical maturity
Formed from either cartilage material or sheet of connective tissue
Cortical bone
Hard, outer layer, dense
Cancellous bone
Porous/spongy, internal tissue
Axial System
Includes the bones of the skull and vertebral column, plus the ribs, sternum, and hyoid apparatus
Skull
Divided into the bones of the cranium, which surround the brain, and the face, which surround the eyes and respiratory & digestive pathways (nose and mouth)
Vertebral Column
Supports the skull and body and provides protection for the spinal cord.
Comprised of individual bones called the vertebra and is subdivided into the cervical (neck), thoracic, lumbar, sacral, and caudal (tail) types
Ribs
26 ribs attach to the 13 thoracic vertebrae dorsally and 12 of them attach to the sternum (made up of 8 bones) ventrally
Hyoid apparatus
Supports the tongue and larynx and is comprised ~9 articulated bones in the dog
Appendicular Skeleton
Includes the bones of the limbs (two thoracic/fore and two pelvic/hind)
Two Thoracic/for Limbs
Divided into the bones of the shoulder girdle (scapula & clavicle), arm/brachium (humerus), forearm/antebrachium (radius & ulna), and forepaw/manus (multiple carpals, metacarpals, and phalanges)
Two Pelvic/hind Limbs
Divided into the bones of the pelvic girdle (os coxae/hip bone), thigh (femur), leg/crus (tibia and fibula), and hind paws/pes (multiple tarsals, metatarsals, and phalanges)
Joints (articulation)
Union or junction between two or more bones
Can facilitate, allow, and even prevent movement
Combining form for joint is arthr/o
Structural Classification of Joints
Fibrous joints (bones held together by dense collagen fibers)
Cartilaginous joints (bones held together by cartilage)
Synovial joints (contain synovial fluid-filled cavity)
Functional Classification of Joints
Synarthrosis (immovable joint)
Amphiarthrosis (a slightly movable joint)
Diarthrosis (a freely movable joint)
Muscles
Function = produce movement
Comprised of muscle fibers
Can only actively contract
Activated by voluntary and involuntary nerve impulses
Muscle Types
Smooth, cardiac, skeletal
Skeletal muscles
Act on joints, not bones
Must cross a joint to act on it
One or more joints
Attachments vs. origin and insertion
Primary vs. Secondary (and Tertiary) actions
Muscle Action
On limbs, most muscles flex and/or extend joints
Flexion
Bending action, decreases angle between two bones
Flexor surface of joint
Generally the <180 degrees side
Extensor surface of joint
Generally the >180 degrees side
Extention
Increases the angle between two bones
Fibrous (collagen) connective tissue
Ligaments, tendons, aponeuroses, and fascia
Ligament
Connects bone to bone
Tendons & aponeuroses
Connects muscle to bone
Tendons
Cord-like
Aponeuroses
Thin/sheet-like
Fascia
Covers and separates muscles. Thin & often sheet-like
