1857 1883 1928 1955 Today

Germ Theory

Louis Pasteur hypothesizes that disease is caused

by small organisms.

1857 1883 1928 1955 Today

Germ Theory

Louis Pasteur hypothesizes that disease is caused

by small organisms.

Koch’s Postulates

Robert Koch finds 4 conditions that prove a

pathogen causes a disease.

1857 1883 1928 1955 Today

Germ Theory

Louis Pasteur hypothesizes that disease is caused

by small organisms.

Koch’s Postulates

Robert Koch finds 4 conditions that prove a

pathogen causes a disease.

Antibiotics

Sir Alexander Fleming discovers

penicillin.

Bacteria don’t grow around mold!!!

1857 1883 1928 1955 Today

Germ Theory

Louis Pasteur hypothesizes that disease is caused

by small organisms.

Koch’s Postulates

Robert Koch finds 4 conditions that prove a

pathogen causes a disease.

Polio Vaccine

Jonas Salk’s vaccine against polio becomes available. Discontinued

in the U.S. in 1994.

Antibiotics

Sir Alexander Fleming discovers

penicillin.

Polio Comeback!

Worldwide efforts increase to

vaccinate people against polio.

1st line of defense: physical barrier Oils & sweat destroy some pathogens

• Some cells burst• Some cells shrivel

Coat the openings of the body Nose, mouth, ears, eyes, genitals, anus

Lined with cilia & sticky fluids to trap pathogens

Job: Search & destroy Phagocytes: surround & engulf invaders

• Phagocytosis (see animation) Lymphocytes:

• T cells: destroy infected body cells• B cells: Inactivate invaders

bacteria

Antibodies•Proteins made by B

cells

How can they help:1. Bind to antigens of

pathogen (like handcuffs) Causes pathogens to

clump Easy targets for

phagocytes

2. Weakens the cell membrane

Causes them to burst

Interferon• Infected cell

(left) produces and releases interferon

• Uninfected cell (right) absorbs the interferon and creates enzymes to fight the pathogen

Defense ProteinsVirus RNA

New virus

New virus

New virus

New virus

New virus

Interferonproteins

virus

Prevents infections (not a cure)

Vaccination process• Weakened pathogen

is injected Antigens on pathogen

• Immune response: Production of memory

cells (future infections)

Antibodies bind to antigens (current infection)

Goal: Speed up immune response if you encounter the unweakened virus

Defined: microorganisms that cause disease• Viruses: turn cells

into virus making factories

Defined: microorganisms that cause disease• Viruses: turn cells

into virus making factories

• Bacteria: prokaryotes that can release toxic chemicals

Defined: microorganisms that cause disease• Viruses: turn cells

into virus making factories

• Bacteria: prokaryotes that can release toxic chemicals

• Fungi: pierce cells and absorb the nutrients

Defined: microorganisms that cause disease• Viruses: turn cells

into virus making factories

• Bacteria: prokaryotes that can release toxic chemicals

• Fungi: pierce cells and absorb the nutrients

• Protozoans: single cells protista (eukaryotes)

Defined: microorganisms that cause disease• Viruses: turn cells

into virus making factories

• Bacteria: prokaryotes that can release toxic chemicals

• Fungi: pierce cells and absorb the nutrients

• Protozoans: single cells protista (eukaryotes)

• Parasites: grow and feed on a host

Some carried by wind, water, direct contact, indirect contact…

Some carried by vectors• Vector: object that

carries a pathogen

• Examples:1)Malaria – mosquitos

carry the protozoan2)Black Death – carried

by flea’s of mice3)West Nile Virus –

carried by birds, but spread by mosquitos

1) What did Louis Pasteur contribute to our knowledge of medicine?

2) Which part of our immune system coats the openings of the body?

3) Name and describe the two types of lymphocytes.4) What are antibodies and how do they help keep us

from harm?5) Summarize how vaccines are created.6) Which pathogen…

1) absorbs nutrients from living tissue?

2) is prokaryotic?

7) Which illness is spread by mice?8) What is the vector of malaria?