Skeletal and Muscular Systems Flashcards
what is the purpose of the musculoskeletal system
- forms the basic frameowrk of the vertebrate body
- muscles and bones work in close coordination to produce voluntary mvoement
- physical support and locomotion are also functions
what is the purpose of the endoskeleton
- serves as a framework within vertebraet systems
- muscles are attached to the bones permitting movement
- endoskeleton also provides protection by surrounding delicate vital organs in bone
- rib cage protects the thoracic organs (heart and lungs)
- skull and vertebral column protect the spinal cord
what is cartilage
- one of two major components of the skeleton
- type of connective tissue that is softer and more flexible then bone
- retined in places where firmness and flexibility are needed: external ear, nose, walls of larynx and trachea and skeletal joints
what is responsible for synthesizing cartilage?
chrondrocytes
what is bone and the two types
- bone is a specialized type of mineralized connective tissue that has the ability to withstand physical stress
Compact bone
- dense and does not appear to have cavities when observed by nake dyee
- bony matrix is deposited in structural units called osteons consisting of central microscopic channels called haversian canal
- surrounded by concentric circles of bony matrix (calcium phosphate) called lamellae
Spongey Bone
- much less dense and consists of inerconnecting lattice of boney spicules
- cavities between the spicules are filled with yellow or red bone marrow
- Yellow marrow is inactive and infiltrated by adipose tissue
- Red marrow is involved in blood cell formation
what are osteocytes
- two other cell types found in bone tissue are osteoblasts and osteroclasts
Osteoblasts:
- synthesize and secrete the organic constituents of the bone matrix
- once surrounded by matrix they mature into osteocytes
Osteoclasts:
- large multinucleated cells involved in bone reabsorption wherein bone is broken down and minerals are released into the blood
explain bone formation
- occurs by enochondral ossifcation or inramembranous ossifcation
- endochondral ossifcation: existing cartilage is replaced by bone, long bones arise primarily through endochondral ossifcation
- Intramembranous ossifcation: mesenchymal (embryonic or undifferentiaed) connective tissue is transformed into and replaced by bone
what is the axial skeleton and how are bones held together
- axial skeleton is the basic frameowrk of the body, consists of skull vertebral column and rib cage
- it is the point of attachment of the appendicular skelton which includes the bones of the appendages (limbs) and the pectoral and pelvic girdles
- sutures or immoveable joints hold bones of skull together
- bones that move relative to one another are held by moveable joints and are supported by ligments
what are ligaments and tendons
- ligaments serve as bone-to-bone connectors
- tendons attach skeletal muscle to bones and bend the skeleton at moveable joins
what are origins and insertion
- point of attachment of a muscle to a stationary bone (proximal end of limb muscles) is the origin
- the point of attachment of a muscle to a bone that moves (distal end of limb muscles) is the insertion
extension vs flexion
extension indicated the straightening of a joint
- flexion refers to te bending of a joint
what does muscle tissue consist of and what are the 3 types of musle in mammals
- muscle tissue consists of bundles of specialized contractile fibers fild be connective tissue
- types: skeletal, smoother and cardian
what is involved in nervous control of the muscular system
axons of the pyramidal cells of the motor cortex which descend from the brain to synpase on lower motor neurons in the brain stem and spinal cord
- pyramidal and extrapyramidal system
what is the pyramidal system and extrapyramidal system
pyramidal:
- contains no intervening synpases
- able to provide rapid commands to the skeletal muscles and various other organs
Extrapyramidal
- issues somatic motor commands as a result of processing performed at the unconcious involuntary level
- red nucleus located in the mesencephalon is the commponent of the extrapyramidal system primarily in control of skeletal muscle tone
what is skeletal muscle and what is it composed of?
- responsible for voluntary movements and is innervated by the somatic nervous sytem
- each fiber is a multinucleated cell created by the fusion of several mononucleated embryonic calls
- each fiber contains myofibrils which divide into contractile sacromeres
- myofibriles are envolved by sacromeres reticulum which stores calcium ions
- cutoplasm of muscle fiber is called sarcoplasm and membrane called sarcolemma