Science Lesson!:)

1. Science Lesson!:) • Michelle Oh, Christine Kim

2. *the skin*The immune system

3. The Skin • Largest organ in the human body • Has many important jobs in the body

4. PROTECTS YOUR BODY • Forms a barrier that keeps harmful substances outside the body (protects body from injury) • The barrier also helps keep important substances in (Ex. water)

5. Maintains body Temperature • Blood vessels & Sweat glands • Become warm->Blood vessels enlarge->Amount of blood that flows through them increases->Heat moves from the body moves into the outside environment • Sweat glands produce perspiration when you become warm, and the perspiration evaporates from your skin, and your skin’s temperature goes down

6. Eliminates Wastes • Perspiration contains dissolved waste • Whenever you sweat or perspire, you are eliminating waste

7. Gathers Information • The nerves in your skin provide information about things such as pressure, pain, and temperature

8. Producing Vitamin D • Some skin cells produce vitamin D in the presence of sunlight

9. Parts of the Skin • Organized into two main layers: epidermis & dermis

10. Epidermis • Does not have nerves or blood vessels • Epidermis cell life cycle: start out deep in the epidermis->mature and move upward as new cells form beneath them->after two weeks they die and become part of the epidermal surface layer->another two weeks they are shed and replaced by dead cells below

11. Epidermis Function • Outer layer of skin • Dead cells on the surface provides protection • The shedding of dead cells carries away bacteria • Some cells produce fingernails • Other cells in the epidermis produces melanin

12. Dermis • Inner layer of skin • Contains nerves and blood vessels

13. Caring for your skin • Healthy Diet • Keeping your skin clean • Limiting sun exposure

14. Immunity: the body’s ability to destroy pathogens before they can cause disease

15. Active Immunity • When a person’s immune system produces antibodies in response to the presence of pathogen (Ex. chicken pox) • Result from either getting the disease or being vaccinated

16. Immune Response • T and B cells help destroy pathogen

17. Vaccination • Process in which harmless antigens are delibarely introduces into a person’s body to produce active immunity • Can gain active immunity • Vaccine, used for vaccination, consisst of pathogens that have been weakened or killed but can still trigger the immune system to go into action

18. first line of defense • : THE SURFACE OF THE SKIN, BREATHING PASSAGES, STOMACH FUNCTION • trap & kill pathogens

19. Skin- exposed to oil and sweat <may fall w/ dead cells> • Breathing passages- come in w/ inhale ex.nose, pharnx, etc. • Mouth & stomach- some found in food • saliva breaks down food

20. Second line of defense • : INFLAMMATORY RESPONSE :FLUID & WHITE BLOOD CELLS LEAK TO TISSUES • White blood cell- disease fighters • Inflammation - blood vessels widen, white blood cells transfer -> swollen • Fever- helps fight infections

21. THIRD LINE OF DEFENSE • : IMMUNE RESPONSE: REACTS TO EACH KIND OF PATHOGENS • Lmphocytes: white blood cell (distinguish different kind fo pathogens)

22. (Continued) • LYMPHOCYTES: • T cells: identify the kinf of pathogen • Antigens: from or outside of the body? • B cells: produce proteins that destroy pathogen

23. AIDS • AIDS: Acquired Immuneodeficiency Syndrome • HIV (human immunodeficiency virus) : virus that cause AIDS • if fluids come in conctact, infection!

24. When you get sick • Antibiotics- helps when infected by bacteria • no medications for common cold - plenty of rest • over the counter medications-> comfortable • drink plenty of fluid

25. Passive immunity • : WHEN ANTIBODIES ARE GIVEN TO THE PERSON • babies need passive immunities before birth