Skeletal, Muscular, and Integumentary Systems Chapter 36 1
36-1 The Skeletal System l Function of the Skeletal system 1. Support the body 2. Protect internal organs 3. Provides for movement 4. Stores mineral reserves 5. Blood cell formation 2
Structure of Bones Spongy bone Compact bone Periosteum Haversian canal Compact bone Bone marrow Spongy bone 3 Osteocyte Artery Periosteum Vein l Bones are a solid network of living cells and protein fibers surrounded by deposits of calcium salts
4 l Periosteum layer of conective tissue that surrounds the bone l Compact bone dense, strength and support l Osteocytes mature bone cells embedded in bone matrix Haversian Canals network of tubes that run through bone containing nerves and blood vessels l Osteoclast line surfaces of the bone, break down bone l Osteoblast build bone
l Spongy bone ends of long bone, middle of short, flat bone, less dense, adds strength w/o adding mass l Medullary Cavity Contains bone marrow l Red - produces blood cells (white, platelets) l Yellow contains fat cells 5
Development of Bone l Embryonic skeletons are made up almost entirely of cartilage No blood vessels, collagen, elastin It is dense and flexible l Epiphyseal platecartilage growth occurs l Eventually replaced by bone l Ossification the process by which cartilage is replaced by bone Osteoblast secrete minerals l When the osteoblast become surrounded by minerals they become mature osteocytes 6
Section 36-1 Joint Muscle Tendon l Jointwhere bones attach to one another Femur Patella Bursa Ligament Synovial fluid Cartilage Fat Fibula Tibia 7
Types of Joints 8 1. Immovable- fixed joints that allow no movement 2. Slightly movable have restricted movement 3. Freely movable allow movement in one or more directions Ball-and-Socket Joint Pivot Joint Humerus Clavicle Ball-andsocket joint Scapula Fibula Hinge Joint Hinge joint Femur Patella Humerus Radius Ulna Pivot joint Saddle joint Saddle Joint Metacarpals Carpals
36-2 The Muscular System l Function of the muscular system Control body movement Help circulate blood Move food through digestive system 9
36-2 The Muscular System l Types of Muscle Skeletal Muscle l usually attached to bone l Responsible for voluntary movement l Many nuclei l Striated l In bundles 10
Figure 36-7 Skeletal Muscle Structure Skeletal Muscle Structure Section 36-2 11
12 l Smooth Muscle Involuntary Spindle shaped, one nucleus, not striated Move food and blood Can work without nerve stimulation
l Cardiac- Found in the heart Striated with one or two nuclei Usually not under direct control of nervous system 13
Muscle Contraction l Muscle contraction is when a thin filament (actin) passes by a thick filament (myosin). Relaxed Muscle Z line Section 36-2 Myosin Actin Z line Actin Movement of Actin Filament Sarcomore Binding sites Crossbridge Contracted Muscle Myosin 14 Cross-bridges Z line During muscle contraction, the knoblike head of a myosin filament attaches to a binding site on actin, forming a cross-bridge. Powered by ATP, the myosin crossbridge changes shape and pulls the actin filament toward the center of the sarcomere. The cross-bridge is broken, the myosin binds to another site on the actin filament, and the cycle begins again.
Control of muscle Contraction l Impulse from motor neurons control the contraction of skeletal muscle Acetylcholine (neurotransmitter) is released from the motor neuron across the neuromuscular junction. l Causes an impulse in the cell membrane of the muscle fiber l Causing the release of Ca+ ions l Ca+ affect proteins that allow actin and myosin to react 15
How Muscle and Bone Interact l l Skeletal muscle produce movement by contracting. Individual muscles can only pull in one direction Most skeletal muscle work in opposing pairs Attached to bone by tendon Figure 36-11 Opposing Muscle Pairs Movement Movement Biceps (relaxed) Biceps (contracted) 16 Triceps (relaxed) Triceps (relaxed)
Integumentary System l The skin Serves as a barrier against infection and injury Regulates body temperature Removes waste from the body Provides protection against ultraviolet radiation 17
Section 36-3 Composition of the Skin 18
Epidermis l Epidermis is the outer layer of the skin Dead layer of cells Contains Keratin a fibrous protein l Cells containing keratin form a waterproof barrier Contains Melanin l Provides protection against UV radiation 19
Dermis l Dermis is the inner layer of skin composed of living tissue l Interacts with other systems to maintain homeostasis l Contains Collagen, blood vessels, sensory receptors, smooth muscle, hair follicles, sweat glands and sebaceous glands l Hair &Nails 20