Presentation on theme: "Skeletal, Muscular & Integumentary Systems 1. Skeletal System 2 FUNCTIONS: Supports the body Protects internal organs Provides for movement – levers act."— Presentation transcript:
Skeletal, Muscular & Integumentary Systems 1
Skeletal System 2 FUNCTIONS: Supports the body Protects internal organs Provides for movement – levers act with muscles Stores mineral reserves Provides a site for blood formation
Skeletal System Divisions 3 Axial – supports the central axis of the body (skull, vertebral column, rib cage Appendicular – bones of the arms, legs, pelvis & shoulder
Bone Structure 4 Bones are living tissue – a solid network of cells & protein fibers that are surrounded by hardened deposits of calcium salts Outer layer = periosteum (tough connective tissue) Thick inner layer = compact bone with Haversian canals Second inner layer = spongy bone Innermost layer = bone marrow Yellow marrow – mostly fat cells Red marrow – produces rbc, some wbc, platelets, contains stem cells
Bone Development 5 An embryo skeleton is almost entirely cartilage Strong, flexible connective tissue No blood vessels Cartilage is replaced by bone during the process of ossification Ossification begins 6-7 months before birth Bone growth occurs at the ends of long bones
Bone Connections 6 Joint – place where one bone connects to another bone Bones connect to bones through ligaments Joint Types: Immovable joint (fixed joints) – allow no movement between bones that touch each other (skull) Slightly movable joint – small amount of restricted movement (slight separation from each other) (vertebrae) Freely movable joint – permit movement - ball-and-socket- hinge - saddle- pivot
Muscular System 8 Muscles are specialized tissue that can contract and relax. Muscles work with the skeletal system to allow movement. Three types of muscles: Skeletal – attached to bones to allow voluntary movement Smooth – usually not under voluntary control Cardiac – heart muscle
Skeletal Muscle 9 Alternating light & dark bands (striation) Usually voluntary control Large cells that can have many nuclei Found all over the body – usually attached to bones
Smooth Muscle 10 Spindle –shaped cells One nucleus Found in walls of hollow structures (blood vessels, stomach, intestines) Involuntary control
Cardiac Muscle 11 Striated Has one or two nuclei per cell Usually involuntary control Found ONLY in the heart
Skeletal Muscle Anatomy 12 Skeletal muscle consists of bundles of muscle fibers Bundles of muscle fibers are composed of individual muscle fiber cells Each muscle fiber consists of myofibrils that have light & dark bands (striations) Each myofibril is made up of thick filaments (myosin protein) & thin filaments (actin protein) A unit of alternating actin & myosin = sarcomere, separated by a dense Z band matter
Muscle Contraction Control 14 The axon terminal contains vesicles with the neurotransmitter Acetylcholine (Ach). An action potential causes the vesicles to release the Ach across the neuromuscular synapse. This causes the release of Ca + in the muscle fiber causing actin & myosin to interact. As long as Ach is released, the muscle will contract. As soon as the Ach is stopped, the muscle relaxes.
Muscles and bones 15 Skeletal muscles connect to bones through tendons. There are usually several tendons connecting many muscles around a joint. Muscles usually act in opposing pairs.
Integumentary System 16 Integument = covering Skin Hair Nails Some glands (found in skin) Skin primary functions: Barrier against infection & injury Helps regulate body temperature Removes waste products Protection against UV radiation
Hair & Nails 18 Formed from keratin (fibrous protein) Forms horns, reptile scales, bird feathers, porcupine quills Hair is produced at the base by hair follicles Sebaceous (oil) glands help maintain hair health
19 Nails grow from an area of rapidly dividing cells = nail root.