Skeletal, Muscular, and Integumentary Systems. Chapter 36

Transcription

1 Skeletal, Muscular, and Integumentary Systems Chapter 36 1

2 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

3 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 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

5 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

6 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

7 Section 36-1 Joint Muscle Tendon l Jointwhere bones attach to one another Femur Patella Bursa Ligament Synovial fluid Cartilage Fat Fibula Tibia 7

8 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

9 36-2 The Muscular System l Function of the muscular system Control body movement Help circulate blood Move food through digestive system 9

10 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

11 Figure 36-7 Skeletal Muscle Structure Skeletal Muscle Structure Section

12 12 l Smooth Muscle Involuntary Spindle shaped, one nucleus, not striated Move food and blood Can work without nerve stimulation

13 l Cardiac- Found in the heart Striated with one or two nuclei Usually not under direct control of nervous system 13

14 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.

15 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

16 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 Opposing Muscle Pairs Movement Movement Biceps (relaxed) Biceps (contracted) 16 Triceps (relaxed) Triceps (relaxed)

17 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

18 Section 36-3 Composition of the Skin 18

19 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

20 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