Host Defenses

mouth: enzymes

break down cell walls of invaders

mouth: bacteria

help get rid of parasites

skin: keratin

acts as waterproof barrier to prevent parasite entrance

skin: dryness

is an inhospitable environment for parasites

skin: sebum

can be toxic to some invaders

respiratory system: mucus membranes

line body openings and prevent parasites from gaining access

respiratory system: macrophages

engulf microorganisms

digestive system: acids

create a harsh environment for parasites

digestive system: peristalsis

keeps food moving and pushes parasites out

digestive system: bacteria

may attack parasites

bacteria

compete and lower pH of specific body areas*mouth, digestive tract, skin, respiratory system)