1 Skin/Bone/Muscle NotesCh. 17 EQ: What does the skin do to maintain homeostasis and how does it provide protection from disease and other environmental factors?

2 Homeostasis Homeostasis is the regulation and maintenance of the internal environment of the human body. e.g. – temperature, nutrient levels, CO2 /O2 levels

3 Levels of OrganizationCells, tissues, organs, organ systems, and whole organism Tissues are groups of similar cells working together Epithelial tissue Connective tissue Muscle tissue Nervous tissue

4 Levels of OrganizationOrgans are different tissues working together Organ systems are two or more organs working together Organism is all organ systems working together

5 Organ Systems

6 Integumentary(Skin) SystemStructure Skin, hair, nails, sweat and oil glands Function Acts as a barrier against infection, injury, UV radiation; helps regulate body temperature Shivers, sweating, goose-bumps

7 Integumentary System Other important rolesRemoves wastes and other substances through pores and glands Water Salts Urea There are 2 main layers of the skin Epidermis Outermost layer and contains keratin which makes cells waterproof and tough Melanin is a dark pigment that absorbs UV rays

8 Integumentary System Dermis – lower layer of skin and contains:Sweat glands Oil glands Pressure receptors Blood vessels Hair follicles

9 Skeletal System Structure Bones, cartilage, ligaments, tendonsFunction Supports and protects vital organs, allows movement, stores minerals, serves as the site for red blood cell protection

10 Skeletal System The skeletal system is split up into 2 different categories: Axial skeleton Includes the skull, rib cage and spinal column Appendicular skeleton Includes shoulder blades, pelvis, legs, arms, feet and hands

12 Bone Marrow Bone is made up of different parts: PeriosteumCompact bone Spongy bone Bone Marrow In Red Bone Marrow red blood cells are produced Yellow Bone Marrow is mostly made of fat

13 Muscular System Structure: Skeletal, smooth and cardiac muscleFunction: Produces voluntary and involuntary movements, helps to circulate blood and move food through digestive system

14 Muscular System Three types of muscle tissue Skeletal MuscleSmooth muscle Cardiac muscle

15 Skeletal Muscle Attaches to the skeleton by tendonsTendons connect muscle to bone Skeletal muscles are mostly voluntary

16 Smooth Muscle Smooth muscle lines organs and is involuntaryMove food through digestive organs Empty liquid from bladder Control width of blood vessels

17 Cardiac Muscle Cardiac muscle is found only in the heartPumps blood throughout body Controlled by pacemaker Contains more mitochondria than skeletal muscle cells

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19 Muscle Contraction The muscular system works with the nervous system to know when to contract and how many muscle fibers to fire. Muscle Fibers Made of myofibrils

20 Muscular Contraction Each myofibril is divided into sarcomeresSarcomeres contain filaments that cause contraction Actin filaments are pulled during contraction Myosin filaments pull actin during contraction