Host Defenses

Innate Immunity: Non-specific

skin and mucous membranes

• physical protection (4)

• skin layers

• secretes mucus

• cilia

• washing action (tears, saliva, urine)

non-specific defenses

innate immunity

• the body's natural, immediate defense

• against any pathogen

specific defenses

adaptive immunity

• develops throughout a person's life

• after exposure to a specific microbe

• immune to one particular pathogen

skin and mucous membranes

• chemical protection (3)

• sebum → fatty acids → lowers pH

  • creates a bad environment for microbes to thrive

• gastric acid

  • pH: 1.2-1.3

  • kills bacteria

  • EXECPT Helicobacter pylori

• lysozyme

  • tears, saliva, perspiration

cellular defenses

• phagocytes

cell eating

• engulfs and destroys pathogens

• some white blood cells

cellular defenses

• blood proportions

60% → plasma

40% → erythrocytes, leukocytes, platelets/thrombocytes

erythrocytes

red blood cells

leukocytes aka PMNs

white blood cells

• phagocytic

• act like amoeba (engulf pathogens)

platelets/thrombocytes

helps with clotting

leukocyte

• neutrophils

type of white blood cell that is active in initial infection

• can enter tissues

• increase in number if bacterial infection

• band → segmented → hypersegmented

leukocyte

• eosinophils

type of white blood cell that is somewhat phagocytic

• increase in number if parasite or allergy

leukocyte

• basophils

type of white blood cell that isn’t phagocytic

• releases histamines

• role in allergies and inflammation

leukocyte

• monocytes

type of white blood cell that matures into macrophages

• phagocytic

leukocyte

• lymphocytes

type of white blood cell that is part of adaptive immunity

• B and T cells

• increase in number if viral infection

what is leukemia?

overgrown and abnormities of the cell line

• increased number of immature white blood cells in the bone marrow and blood

• impaired blood cell function.

WBC Differential Count

measures the percentage of white blood cells in a blood sample

• differentiates WBCs

• identifies them

WBC Differential Count

• most common to least common

most common to least common

• neutrophils

• lymphocytes

• monocytes

• eosinophils

• basophils

when can inflammation occur

can occur with any tissue injury

• infection

• wound

• burns

• sprained ankle

5 symptoms/signs of inflammation

1. heat around the area

2. redness

3. swelling

4. pain

5. loss of function

inflammation benefits

• destroys agent of injury

• limits injury so it doesn’t get worse

• repairs damaged tissue

when does a fever usually occur

usually due to viral or bacterial infection

how is a fever helpful (4)

• inhibits some microbes

• hard for microbes to grow → too hot

• speeds tissue repair

• helps interferon work better

antimicrobial substances

• how does interferons work?

cell infected with virus → make interferon → goes to uninfected cells → tells them to make antiviral proteins

• tells neighboring cells to protect themselves

• naturally made in body

limits of interferons (3)

• doesn’t help infected cells

• short term (important with colds & influenza)

• clinical uses: side effects in high doses

antimicrobial substances

• complement functions

• destroy microbes (cytolysis)

• enhances ability of phagocytosis

• important in inflammation

what is a complement

series of proteins in the blood