Aspects to consider Entry points for infection Infection

Aspects to consider - Entry points for infection - Infection barrier…barriers - Species barriers

Possible modes of infection: - Skin contact Contact with sensitive areas of the body Ingestion Inhalation Injection into the brain Transplantation of cells/tissues Injection of purified protein Contaminated surgical tools Mother to child

Skin

Ingestion pharynx epiglottis vocal cords esophagus larynx trachea

The stomach wall

Cell types in the epithelium of the stomach gastric crypts

Safety: mucus-bicarbonate barrier

Epithelium of the intestine outside Tight junctions cell inside

Membrane as a barrier H 2 O forms H-bonds water Bound to water energy Non-polar molecules Polar molecules e=80 e=2 e=80

Epithelium of the intestine outside Tight junctions cell inside

Bacterial Lactose-Proton co-transporter (Lac Permease 1 PV 7. pdb) R 144 E 126 E 269 R 302 H 322 R 144 R 302 E 269 side view top view

First must cross the epithelium, then must get into the blood stream Blood stream is the fast track. Moving from place to place outside the blood is slow.

The hepatic portal system

The hepatocytes form hexagonal lobules

Recognition: specific interaction No effect Cell is changed

Central Nervous System

Chapter 9 Fig. 9 -9 sensory fields motor areas association areas (cortex) movement (basal, limbic) emotion, learning, memory (amygdala, hippocampus) sensory-motor integration (thalamus) movement coordination (cerebellum) autonomic functions (hypothalamus, midbrain, pons, medulla)

Inhalation

Ciliated respiratory epithelium of airways 17 -8

Blood as a mechanism of spread of infection Hematocrit (37 -54%) The hemoglobin (12 -17 g/d. L) Red cell count (3. 9 -5. 6· 106/m. L) and morphology Total white cell count (4 -11· 103/m. L) and differential count Platelet count (2 -5· 105/m. L)

macrophages

Penetration due to damage

Lymphatic system

Possible modes of infection: - Skin contact Contact with sensitive areas of the body Ingestion Inhalation Injection into the brain Transplantation of cells/tissues Injection of purified protein Contaminated surgical tools Mother to child