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skeletal system (tissues (compact bone characteristics:
outer part of…
skeletal system
tissues
compact bone characteristics:
- outer part of every bone
- it's strong and rigid
- composed of osteons
- have performing canals
spongy bone characteristics:
- located in ends of long bones or inside in the middle flat bones
- made out of trabeculae
- has extracellular matrix, osteocytes but no osteons
- it's a location of red bone marrow
Red bone marrow is a gelatinous material found inside embryo/ fetus. It fills all the spaces inside bones of kids until age 7. In adults it can be found in vertebrae, coxal bones, sternum, ribs, skull and ends of long bones. It makes blood cells.Yellow bone marrow can be found in medullary cavities in long bones. It is an energy storage.
the major structural components:
- bones (35% organic- cells with extracellular matrix and 65% inorganic minerals)
- ligaments (connect bone to bone and serves to hold them together and keep them stable)
- tendons (connect bone to muscle and serves to move bone or structure)
- joints/articulations (connection made between bones)
the major functions of the skeletal system:
- provide support (framework for connection of soft tissues)
- movement (with help of muscles)
- protection (cranium, rib cage, vertebrae)
- mineral storage
- blood formation (red bone marrow)
- energy storage (yellow bone marrow)
types of bone cells:
- osteogenic cells that are located in endosteum and periosteum and differentiate into different cells
- osteoblasts (bone makers)
- osteocytes (maintain bone)
- osteoclasts (break organic portion of bone)
skeletal muscles
properties: contractility, excitability, extensibility, elasticity
functions :
- produce movement for bones, blood, content of hollow organs
- opening and closing passage ways (sphincter muscles)
- maintaining posture and stabilizing joints
- generate heat
connective tissue layers:
- endomysium (reticular connective tissue between muscle fibers that create space to keep them separated and allows small blood vessels to run next to muscle fibers)
- perimysium (irregular connective tissue that covers each fascicle)
- epimysium (dense irregular connective tissue that binds fascicles together)
- deep fascia (dense irregular connective tissue that binds together whole muscles
components of a skeletal fiber:
- sarcolemma (plasma membrane)
- myofibril (makes muscle fiber)
- transverse tubules (wraps around each myofibril)
- sarcoplasmic reticulum (storage of calcium)
- terminal cisterns (calcium storage place)
joints
cartilaginous :
- synchondrosis (immovable joint between two bones bound by hyaline cartilage found in first rib and manubrium and epiphyseal plate)
- symphysis ( bones are bind by hyaline cartilage and fibrocartilage, found in pubic symphysis (immovable) and between intervertebral discs)
synovial
structural types
pivot joint: it has a shape of sleeve and axle. Makes rotation possible, found between atlas and axis and ulna and radius.
condylar joint: it connects oval articular surfaces, allows flexion, extension, adduction and abduction, is found in wrist joints.
hinge joint: it has a shape of cylinder and trough, makes flexion and extension possible, is located in elbow and between phalanges.
ball-and-socket joint: it has a shape oh head and cup, it allows flexion, extension, adduction, abduction as well as rotation and is found in hip and shoulder
saddle joints: it is shape like a saddle with a rider on it, it allows adduction, abduction, flexion and extension and can be found in carpometacarpal joints in thumb
plain joint: in flat, articular surfaces, makes gliding movement possible, located between carpals (intercarpals joints) and tarsals (intertarsal joints)
components:
- presence of joint cavity surrounded by joint capsule and filled with synovial fluid.
-presence of articular cartilage on a surface of a joint
- bursae - sacs filled with synovial fluid located between tendons and bone, bone and skin, ligaments and bone and muscle and bone.
fibrous:
- sutures (bones jointed together with a very short interconnecting fibers. The is no movement. It is found in skull)
- Syndesmosis (bones are widely separated but held together with a dense regular connective tissue. Examples: tibiofibular joint, carpals, tarsals, very little movement)
- Gomphosis ( narrow joint between tooth and alveolus. Fibers are called periodontal ligaments, no movement)