???

• What causes a black eye?– Blood vessels burst causing blood to pool in

that area.

• How many bones are in the human body?– 206

• What is the human body’s largest organ?– Skin

Chapter 37

Introduction to Body Structure

Section 37.1

Body Organization

4 Levels of Structural Organization

• Organ Systems

• Organs

• Tissues

• Cells

• Tissue– Group of similar cells

that perform a common function

– Building blocks of the human body

4 Kinds of Tissues• 1. Epithelial

– Lines most body surfaces– Protects other tissues from dehydration and physical

damage

• 2. Nervous– Consists of nerve cells and supporting cells– Carries info. throughout the body

• 3. Connective– Supports, protects and insulates– Includes fat, cartilage, bone, tendons and blood

• 4. Muscle– Enables movement of body structures

3 Types of Muscle Tissue• 1. Skeletal

– Voluntary– Moves bones in the trunk and limbs

• 2. Smooth– Involuntary– Line the walls of blood vessels and some organs

• 3. Cardiac– Involuntary– Found in the heart– Pump blood throughout the body

Stem Cells• Give rise to all types of cells

• Can form any type of body tissue

• Can divide indefinitely in embryos

• Can possibly repair damaged tissues

• Produce blood cells in bone marrow

• Adult stem cells only divide ~100 times

Organ Systems• A group of organs that

work together to carry out a major activities or processes– Table 1 p. 848

• Circulatory

• Digestive

• Endocrine

• Excretory

• Immune

• Integumentary

• Muscular

• Nervous

• Reproductive

• Respiratory

• Skeletal

Body Cavities• Fluid-filled spaces that house and protect

major internal organs• 5 Types

– 1. Cranial• Brain

– 2. Spinal• Spinal cord

– 3. Thoracic• Heart and lungs

– 4. Abdominal• Digestive organs

– 5. Pelvic• Reproductive organs

Endothermy

• Organisms that maintain a constant internal temperature

• Critical to homeostasis

• Negative feedback system– Output of a system acts to oppose changes to

the input of a system

Answer the Following ?’s• List the 4 levels of structural organization

within the body.

• Describe the 4 types of body tissues.

• List the body’s major organ systems and describe their function.

• Describe how endothermy helps maintain homeostasis.

???

• What part of your skeletal system do you think is the most important? Why?

Section 37.2

Skeletal System

The Skeleton• Allows us to stand and perform everyday

activities (along with our muscles)

• Axial Skeleton– Bones of the skull, spine, ribs

and sternum– 80

• Appendicular Skeleton– Bones of the arms, legs, pelvis

and shoulder– 126

Axial Skeleton• 29 bones in the skull

– 8 form the cranium– 14 are facial bones– 6 middle ear bones– 1 supports your tongue

• 26 vertebrae

• 12 pairs of ribs

• 1 sternum

Appendicular Skeleton• Forms limbs (arms & legs)

– Shoulders– Arms– Hips– Legs

• Shoulder blades

• Collar bones

• Pelvic bones

Structure of Bone• Compact bone

– Dense tissue, provides support

• Spongy bone– Loose structure of connective tissue

• Bone Marrow– Soft tissue inside the bone– Red

• Production of blood cells– Yellow

• Consists of fat

• Periosteum– Hard, outer layer

Growth of Bones• Haversian Canals

– Hallow channels in compactbone where new bone cellsare added in layers

• Osteocytes– Maintain the mineral

content of bone– Blood vessels that run

through haversian canalsprovide nutrients toosteocytes

Osteoporosis

• Occurs when bonetissue is lost, andbecomes less dense

• Porous bone

Joints

• Where 2 bones meet

• Cartilage cushions joints

• Held together by ligaments– Prevent bones from moving too far in one

direction

3 Main Types of Joints• Immovable

– Little or no movement• Cranial bones

• Slightly Movable– Limited movement

• Vertebrae

• Freely Movable– Movement allowed

• Knee

Movable Joints• Ball-and-socket

– Shoulders and hips

• Pivot– Rotation– Turning of head

• Hinge– Bending and straightening– Elbows, knuckles, knees

• Gliding– Sliding– Wrists and ankles

• Saddle– Rotation, bending and straightening– Base of thumbs

Disorders of Joints

• Rheumatoid arthritis– Inflammation of freely movable joints– Cells of immune system attack tissues around

joints

• Osteoarthritis– Degeneration of cartilage– Bones rub together

Section 37.3

Muscular System

Muscles and Movement

• Everyday activities require muscles.– Walking– Running– Brushing your teeth– Eating– Writing notes

Movement of the Skeleton

• Tendons– Connect muscles to bones

• Origin– Bone that stays stationary during muscle

contraction• Insertion

– Bone that moves when muscle contracts

Movement of the Skeleton

• Flexor– Muscle that causes a joint to bend

• Extensor– Muscle that causes a joint to straighten

Muscle Structure• Actin and Myosin

– Protein filaments of connective tissue that holds muscle cells together and provide elasticity.

• Myofibrils– Muscle fibers that have a cylindrical structure

• Sarcomere– Area between the Z lines of myofibrils

• Myofibrils and sacromeres are made up of actin and myosin

Muscle Contraction• Step 1

– Sarcomere is relaxed, myosin and actin partially overlap each other

• Step 2– Nerve cells povide signal– Actin and myosin overlap more– Sarcomere becomes shorter

• Step 3– Sarcomere is fully contracted– Actin and myosin fully overlap each other

Aerobic and Anaerobic Energy Pathways

• Aerobic respiration requires ATP to power muscle contractions

• Glycolysis (an anaerobic process) supplies ATP during intense activity

• When aerobic and anaerobic pathways cant keep up we use glycogen and fat as energy sources

Exercise and Fitness• Why does exercise become easier after

prolonged training?– More oxygen supplied to muscles– More ATP available for contractions– Reduces muscle fatigue

• Why is stretching necessary?– Over-stretched muscles can tear

• How do muscles increase in size?– Muscle break apart and repairing makes them

bigger

Section 37.3 Questions

• Describe the action of muscles moving in pairs in the body.

• Describe the different parts of the muscle and how they play a role in muscle contraction.

• How is energy supplied to the muscles for contraction?

Muscle and Bone Research Part II• Use the supplies on the side counter to

complete a detailed drawing of your muscle and your bone.– Try to be as detailed as you can.

• Muscle fibers• Structure of bones

• Once your drawings are complete attach them to the right side of the cardboard cutout or the piece of butcher paper that represents the back of the skeleton.

???• List 5 things you did so far today that required

the use of your muscular system.

• List any other organ system on p. 848 that your body has used, and the activity that required that system to function.

• Your skin has many functions. How is it helped/protected you today? List as many as you can.

Section 37.4

Skin, Hair, and Nails

Skin• 15% of total body weight

• Largest organ of your body

• Hair and nails form here

• Protection fromdehydration

• 2 main layers:– Epidermis – Dermis

Skin• Epidermis

– Outermost layer of the skin

• Keratin– A protein that makes skin tough and

waterproof• Melanin

– Cells that give skin its color

• Skin cells aren’t repaired, they are replaced

Skin• Dermis

– Functional layer of skin that is beneath the epidermis

– Contains hair follicles, nerve cells, blood vessels, other skin cells

– Nerve cells in dermis give us the sense of touch

• Temperature Regulation– Blood vessels flowing near the surface

release heat from the body– Sweat glands also releases heat

Skin

• Subcutaneous tissue– Layer of connective tissue, mostly fat, found

underneath the dermis– Provides insulation and stores energy

Hair and Nails

• Protrude from the epidermis

• Hair sheds because it is no longer growing

• The white area near the base of your nail is where new nail cells are made

• Nails grow throughout your entire life

Skin Disorders

• Acne– Oil glands in the dermis secrete sebum– Sebum clogs pores causing the oil to build up

• Skin Cancer– Can be caused by over-exposure to UV rays– Carcinomas

• More treatable– Melanomas

• Grow quickly less treatable

Chapter 37 Wrap-Up ?• Describe how the organization of the

different structures in your body allow you to complete the everyday activities you enjoy, and how they help you function in a stable manner.

– Organ systems, Organs, Tissue, Cells– Bones, Muscle, Skin

• Answer this question on a piece of notebook paper in no less than 5 sentences.