??? • 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
Organ Systems Organs Tissues Cells Tissue Group of similar cells that perform a common function Building blocks of the human body 4 Levels of Structural Organization
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
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 Organ Systems
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 compact bone where new bone cells are added in layers • Osteocytes • Maintain the mineral content of bone • Blood vessels that run through haversian canals provide nutrients to osteocytes
Osteoporosis • Occurs when bone tissue is lost, and becomes 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 from dehydration • 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.