Chapter 36 Skeletal, Muscular and Integumentary Systems 1

Section Outline I. The Skeletal System A. The Skeleton: two subdivisions: Axial and Appendicular 1. Functions a. supports the body b. protects internal organs (brain and internal organs c. provides for movement (levers for muscles to act on) d. stores minerals (calcium) e. site for red blood cell production (produced in red marrow) 2

Appendicular Skeleton The Skeletal System Section 36-1 Skull Sternum Ribs Vertebral column Axial Skeleton Axial Skeleton Appendicular Skeleton Metatarsals Metacarpals Phalanges Clavicle Scapula Humerus Radius Pelvis Ulna Carpals Femur Patella Fibula Tibia Tarsals 3

Section Outline 1. periosteum – a tough layer of connective tissue B. Structure of Bones - a solid network of living cells and protein fibers, surrounded by calcium mineral salts 1. periosteum – a tough layer of connective tissue surrounding a bone 2. Haversian canals – a network of tubes running through compact bone that carry blood vessels 3. spongy bone – strong but light bone found and the ends of long bones, and between compact bone in ribs and skull bones 4. bone cells- three types a. osteocytes – mature bone cells that maintain bone structure b. osteblasts – create new bone tissue c. osteoclasts – break down bone Section Outline Section 36-1 4

Figure 36-3 The Structure of Bone Spongy bone Compact bone Periosteum Bone marrow Haversian canal Osteocyte Artery Vein 5

Section Outline Development of Bones 1. embryonic skeletons are composed of cartilage 2. cartilage is replaced by bone during embryonic development 3. the process of replacement is called ossificaton 4. in early adulthood all the cartilage is replaced by bone (ossification) 6

1. Immovable Joints – allow no movement – skull bones D. Types of Joints 1. Immovable Joints – allow no movement – skull bones 2. Slightly Movable Joints – allow some movement – between bones of lower leg, and between vertebrae 3. Freely Movable Joints – movement in one or more directions a. ball and socket joint –movement in many directions (shoulder and hip) b. hinge joint – movement in one direction (knee and elbow) c. pivot joint – one bone rotates around another (lower arm) d. saddle joint – bones slide in two directions (between wrist and hand) Section 36-1 7

Figure 36-4 Freely Movable Joints and Their Movements Ball-and-Socket Joint Pivot Joint Clavicle Ball-and-socket joint Scapula Humerus Humerus Radius Pivot joint Ulna Hinge Joint Saddle Joint Femur Patella Hinge joint Tibia Fibula Metacarpals Carpals Saddle joint 8

Section Outline E. Structure of joints and skeletal disorders 1. ends of bones in freely moveable joints are covered with cartilage for protection 2. the joint is surrounded by a tough joint capsule that has two layers a. ligaments are strips of connective tissue that hold bones together and stabilize the joint b. the other layer produces synovial fluid, which lubricates the joint 3. bursa are small sacs found in a joint that reduce friction and act as cushions 4. Skeletal System Disorders a. bursitis – inflammation of the bursa b. osteoporosis – a loss of calcium from bones which causes them to weaken Section Outline Section 36-1 9

Figure 36-5 Knee Joint Section 36-1 10 Muscle Tendon Femur Patella Bursa Ligament Synovial fluid Cartilage Fat Fibula Tibia 10

Section Outline II. Muscular System– causes movement of body parts and materials A. Types of muscle tissue 1. skeletal – connected to the skeletal system a. striations – alternating light and dark bands seen under a microscope b. under voluntary nervous control c. have many nuclei in each cell 2. smooth muscle – located in internal organs a. no striations present b. involuntary nervous control 3. cardiac muscle – found in the heart a. striations present Section 36-2 11

Section Outline B. Muscle Contraction 1.muscle cells are made up of 2 fibers called myofibrils a. a thin filament called actin b. a thick filament called myosin 2. a muscle contraction happens when actin and myosin slide past each other 3. actin and myosin form cross bridges between them which allows a contraction to take place 4. ATP is used to power the reactions that cause contraction C. Control of Muscle contractions 1.skeletal muscle contraction is controlled by the nervous system 2. a nerve ending connects to each muscle cell at a neuromuscular junction Section 36-2 12

Section Outline 3.when a nervous impulse is sent down a nerve, a chemical is released that causes contraction to begin a. acetylcholine is the neurotransmitter that is released D. Muscle and Bone interaction 1.muscles can only contract, so they are arranged in opposing pairs 2. muscles connect to bones by connective tissue strips called tendons Section 36-2 13

Cycle Diagram 1 Myosin forms cross-bridge with actin 5 2 Myosin returns to original shape Cross-bridge changes shape 4 3 Cross-bridge releases actic Actin pulled 14

Figure 36-7 Skeletal Muscle Structure Section 36-2 15

Figure 36-8 Muscle Contraction Section 36-2 Relaxed Muscle Z line Myosin Actin Z line Movement of Actin Filament Actin Cross-bridge Sarcomore Binding sites Contracted Muscle Myosin Cross-bridges Z line 16

Figure 36-8 Muscle Contraction Section 36-2 Relaxed Muscle Z line Myosin Actin Z line Movement of Actin Filament Actin Cross-bridge Sarcomore Binding sites Contracted Muscle Myosin During muscle contraction, the knoblike head of a myosin filament attaches to a binding site on actin, forming a cross-bridge. Cross-bridges Z line 16

Figure 36-8 Muscle Contraction Section 36-2 Relaxed Muscle Z line Myosin Actin Z line Movement of Actin Filament Actin Cross-bridge Sarcomore Binding sites Contracted Muscle Myosin 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 cross-bridge changes shape and pulls the actin filament toward the center of the sarcomere. Cross-bridges Z line 16

Figure 36-8 Muscle Contraction Section 36-2 Relaxed Muscle Z line Myosin Actin Z line Movement of Actin Filament Actin Cross-bridge Sarcomore Binding sites Contracted Muscle Myosin 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 cross-bridge 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. Cross-bridges Z line 16

Opposing Muscle Pairs Figure 36-11 Opposing Muscle Pairs Movement Biceps (relaxed) Biceps (contracted) Triceps (relaxed) Triceps (relaxed) 17

III. Integumentary System: Skin, hair, nails and several glands Section 36-3 III. Integumentary System: Skin, hair, nails and several glands A. Functions 1. a barrier against infection and injury 2. helps regulate body temperature 3. removes waste products 4. provides protection from ultraviolet light 18

B. Two main layers: Epidermis and Dermis 1. epidermis – upper layer of skin a. top layer of skin is dead, and made up of a waterproofing protein called keratin b. deeper layer is living and produces a dark pigment called melanin (UV protection) c. the epidermis is avascular (no blood vessels) 2. dermis – contains blood vessels, nerve endings, hair follicles, glands, and smooth muscle a. blood vessels help to regulate heat loss and gain b. glands produce sweat and oils to cool the body and keep the skin flexible and waterproof Section 36-3 19

Concept Map Skin Section 36-3 20 functions as a is made up of the Barrier to infection Regulator of body temperature Remover of waste products Protector against UV radiation Epidermis Dermis which is the which is the Outer layer Inner layer 20

Figure 36-13 The Structure of Skin Section 36-3 21

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