Skeletal

• Bones are considered living organs because they are constantly being remodeled and rebuilt.
• Compact Bone = dense, hard, and strong. Found in the outer layer of the bone.
• Layers of bone = compact, spongy, and cancellous
• Spongy bone = porous, flexible inner layer of bone
• Bone marrow is the soft tissue inside the bones that produces blood cells
• Yellow bone marrow stores fat and red blood cells, and produces white blood cells
• Red bone marrow produces red blood cells, white blood cells, and platelets
• Platelets help with blood clotting and are found in the blood
• Babies = 300 bones

  adult = 206
• 5 types of bones = Long, short, flat, irregular, sesamoid
• Long bones have a long shaft and a short head
• Flat bones are thin and used for protection/muscular attachment (ex - scapula)
• Short Bones are wider than long and provides stability but little movement (ex- carpal bones in the wrist)
• Sesamoid bone - found inside tendon/muscle (ex-patella of the knee)
• Irregular bones have a unique shape and are not arranged in a regular pattern (ex- hyoid bone/vertebrae)
• Tendons connect MUSCLE to BONE and are made of collagen fibres
• Tendons aid in movement
• Ligaments connect BONE to BONE and help keep structures stable (ex - joints)
• Cartilage = connective tissue found between bones (ex - nose, ears, rib cage, bronchial tubes)
• Cardiac muscle = involuntary, and striated (found in the heart)
• Smooth muscle = involuntary, non-striated and has the ability to stretch further than cardiac and skeletal (ex - blood vessels, uterus, bladder, eye)
• Skeletal muscle = voluntary, striated
• Most skeletal muscle are attached to bone by tendons
• Skeletal muscles are named based on their location, function, shape, or origin
• Fascia = layer of connective; outermost level that surrounds every muscle
• Layers of skeletal muscle

  • epimysium
  • perimysium
  • endomysium
• Perimysium = layer of deep fascia surrounding a fascicle
• Endomysium = surrounds the individual muscle cell
• Epimysium = outermost layer that surrounds the whole muscle
• Myocyte = muscle cell, muscle fiber, muscle tissue, muscle fiber
• Sacroplasm = muscle cells cytoplasm
• Myocyte —> myofiolated cell —> myofibril —> sarcomere —> muscle fiber
• Myofibrils = long chains of sacomeres
• Sarcomere = basic functional unit of a muscle fiber, composed of a series of actin and myosin filaments