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

larynxesophagus

vocal cords

epiglottis

pharynx

trachea

glottis

Ingestion

The stomach wall

Cell types in the epithelium of the stomach

gastric crypts

Safety: mucus-bicarbonate barrier

K +

N a+

K +

N a+

N a+ G LU

G LUK +

outside

inside

Tight junctions

Epithelium of the intestine

cell

Membrane as a barrier

Non-polar molecules

Polar molecules ener

gy

waterH2O forms

H-bonds

Bound to water

e=80 e=80e=2

K +

N a+

K +

N a+

N a+ G LU

G LUK +

outside

inside

Tight junctions

Epithelium of the intestine

cell

Bacterial Lactose-Proton co-transporter (Lac Permease 1PV7.pdb)

side view top view

R302

R144

E269

E269

R144 H322

E126

R302

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

No effect Cell is changed

Recognition: specific interaction

Central Nervous System

Chapter 9

sensory fieldsmotor areasassociation areas(cortex)

movement (basal, limbic)emotion, learning, memory(amygdala, hippocampus)

movement coordination(cerebellum)

autonomic functions(hypothalamus, midbrain, pons, medulla)

sensory-motor integration(thalamus)

Fig. 9-9

Inhalation

Ciliated respiratory epithelium of airways 17-8

Hematocrit (37-54%)

The hemoglobin (12-17 g/dL)

Red cell count (3.9-5.6·106/mL)and morphology

Total white cell count (4-11·103/mL)and differential count

Platelet count (2-5·105/mL)

Blood as a mechanism of spread of infection

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