Non-Specific Defenses April 3, 2015. Body fights disease in 2 ways 1. Non-specific defense system Protects body from all foreign substances 2. Specific.

Non-Specific DefensesApril 3, 2015

Body fights disease in 2 ways1. Non-specific defense system

Protects body from all foreign substances

2. Specific defense system (aka immune system)

Attacks particular, previously encountered foreign substances

Try to organize the list from the do now into the two systems – we will double check later!

Today, we are focusing on nonspecific defenses. Next class: Immune system

Surface BarriersSkin and mucus membranes prevent pathogens from entering body

Tightly bound cells provide physical barrier Acidic secretions in skin, vagina, and

stomach inhibit bacterial growth Mucus in respiratory and digestive tracts trap

bacteria Saliva and tears contain an enzyme –

lysozyme – that destroys bacteria.

Cellular DefensesThe body has specialized cells that destroy foreign material

Phagocytes (macrophages & neutrophils) – engulf and digest foreign particles, such as bacteria and viruses

Cellular DefensesThe body has specialized cells that destroy foreign material

Phagocytes (macrophages & neutrophils) – engulf and digest foreign particles, such as bacteria and viruses

Natural killer cells (a type of lymphocyte) – destroy cancer / virus infected cells by releasing chemicals that destroy cell membranes.

Watch me!

Watch me 2!

InflammationInflammation occurs when an area that is damaged or infected becomes red, warm, swollen, and painful.

Occurs when damaged cells release chemicals that increase blood flow, make blood vessels leaky, and attract leukocytes.

How does it protect the body?

prevents spread of pathogens to nearby tissue

helps rid body of pathogens and dead cells

Helps speed healing

FeverFever is when the body’s temperature becomes elevated due to infection

Occurs when white blood cells release chemicals that reset the body’s thermostat

How does it protect the body?

reduces bacterial growth by causing the liver & spleen to take up nutrients

increases metabolic rate to speed the healing process

Why do we get the chills when we have a fever?

Turn and TalkReview the list of defenses we made during the do now and categorize them as specific or non-specific defenses.

Then, review for exit ticket!

Exit Ticket1. Which of these describes NK (natural killer)

cells?a) Immune cells that release chemicals to kill

specific, previously encountered pathogensb) Immune cells that release chemicals to kill

any pathogen it encountersc) Immune cells that engulf and destroy

specific, previously encountered pathogensd) Immune cells that engulf and destroy any

pathogen it encounters

Exit Ticket2. Which of these does not characterize the

inflammatory response?a) blood capillaries become leakyb) affected areas become warm and redc) reduces nutrients available to

pathogensd) speeds healing

Exit Ticket3. How does a fever help the body fight disease?

a) by raising body temperature above the tolerance of pathogensb) by decreasing the nutrients available to pathogensc) by reducing pathogen’s metabolic rated) by increasing blood flow to infected areas

Exit Ticket3. How does a fever help body fight disease?

a) by raising body temperature above the tolerance of pathogensb) by decreasing the nutrients available to pathogensc) by reducing pathogen’s metabolic rated) by increasing blood flow to infected areas

Exit Ticket4. Describe three ways the skin and mucus

membranes fight disease (2 are required, one is EC)

Extra credit: Name a phagocyte