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