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Chapter 36 Skeletal, Muscular and Integumentary Systems

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Section Outline

Section 36-1

I. The Skeletal SystemA. 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)

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Skull

Sternum

Ribs

Vertebral column

The Skeletal System

Section 36-1

Axial Skeleton

Appendicular Skeleton

Metatarsals

Metacarpals

Phalanges

Clavicle

Scapula

Humerus

RadiusPelvisUlnaCarpals

Femur

Patella

Fibula

TibiaTarsals

Phalanges

Axial Skeleton

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Section Outline

Section 36-1

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 typesa. osteocytes – mature bone cells

that maintain bone structure

b. osteblasts – create new bone tissue

c. osteoclasts – break down bone

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Spongy bone

Compact bone

Periosteum

Bone marrow

Haversian canal Compact

bone

Spongy bone

Osteocyte

Artery

VeinPeriosteum

Figure 36-3 The Structure of Bone

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Section Outline

Section 36-1

C. 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)

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Section 36-1

D. Types of Joints1. 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)

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Ball-and-Socket Joint

Hinge Joint

Pivot Joint

Saddle Joint

Clavicle

Ball-and-socket joint

ScapulaHumerus

Femur

Patella

Hinge jointTibia

Fibula

Humerus

Radius

Pivot joint

Ulna

Metacarpals

CarpalsSaddle joint

Figure 36-4 Freely Movable Joints and Their Movements

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Section Outline

Section 36-1

E. Structure of joints and skeletal disorders1. 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

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Muscle

Tendon

Femur

Patella

Bursa

Ligament

Synovial fluid

Cartilage

Fat

Fibula

Tibia

Figure 36-5 Knee Joint

Section 36-1

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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

b. involuntary nervous control

Section Outline

Section 36-2

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B. Muscle Contraction 1.muscle cells are made up of 2 fibers called myofibrils

a. a thin filament called actinb. a thick filament called myosin

2. a muscle contraction happens when actin and myosin slide past each other3. actin and myosin form cross bridges between them which allows a contraction to take place4. ATP is used to power the reactions that cause contraction

C. Control of Muscle contractions1.skeletal muscle contraction is controlled by the nervous system2. a nerve ending connects to each muscle cell at a neuromuscular junction

Section Outline

Section 36-2

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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 Outline

Section 36-2

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Actin pulledCross-bridge releases actic

Cross-bridge changes shape

Myosin returns to original

shape

Myosin forms cross-bridge

with actin

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1

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Cycle Diagram

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Figure 36-7 Skeletal Muscle Structure

Section 36-2

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Relaxed Muscle

Contracted Muscle

Z line Myosin Actin Z line

Sarcomore

Cross-bridges Z line

Movement of Actin FilamentActin

Binding sites

Cross-bridge

Myosin

Figure 36-8 Muscle Contraction

Section 36-2

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Relaxed Muscle

Contracted Muscle

Z line Myosin Actin Z line

Sarcomore

Cross-bridges Z line

Movement of Actin FilamentActin

Binding sites

Cross-bridge

Myosin

Figure 36-8 Muscle Contraction

Section 36-2

During muscle contraction, the knoblike head of a myosin filament attaches to a binding site on actin, forming a cross-bridge.

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Relaxed Muscle

Contracted Muscle

Z line Myosin Actin Z line

Sarcomore

Cross-bridges Z line

Movement of Actin FilamentActin

Binding sites

Cross-bridge

Myosin

Figure 36-8 Muscle Contraction

Section 36-2

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.

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Relaxed Muscle

Contracted Muscle

Z line Myosin Actin Z line

Sarcomore

Cross-bridges Z line

Movement of Actin FilamentActin

Binding sites

Cross-bridge

Myosin

Figure 36-8 Muscle Contraction

Section 36-2

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.

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Movement Movement

Biceps (relaxed)

Triceps (relaxed)

Biceps (contracted)

Triceps (relaxed)

Figure 36-11 Opposing Muscle Pairs

Opposing Muscle Pairs

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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

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Section 36-3

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

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Skin

Barrier to infection

Regulator of body

temperature

Remover of waste products

Protector against UV radiation

Epidermis Dermis

Outer layer Inner layer

functions as a

is made up of the

which is the

which is the

Concept Map

Section 36-3

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Figure 36-13 The Structure of Skin

Section 36-3

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Video 2