Unit 1 (2)

Phagocytes Engulf Pathogen

1. Engulfs pathogen

2. Traps it in a phagocytic vacuole

3. Fuses with lysosomes which release lysozymes, these break down the pathogens

4. Presents the antigens

Phagocytes Activate T-Cells

Has proteins on its surface that bind to the antigens presented to it by the phagocytes

This activates the T-Cells

1. Some release substances to activate B-Cells

2. Some attach to antigens and kill the cell

T-Cells Activate B-Cells which divide into Plasma Cells

1. Antibody-Antigen complex forms

2. Activates B-Cells together with substances released from T-Cells

3. Activated B-Cells divide into plasma cells

Plasma Cells make more Antibodies to a Specific Antigen

1. Coat pathogen to make it easier for phagocyte to engulf

2. Coat pathogen to prevent it entering host cell

3. Binding and neutralising pathogen

Cellular and Humoral

Cellular  = T-Cells and other cells they interact with e.g. phagocytes

Humoral = B-Cells and the production of antibodies

1. Sodium ions are actively transported out of the epithelial cells as potassium ions are transported into the epithelial cells

2. The reduction in concentration of sodium ions in the epithelial cells draws in sodium from the intestines by diffusion

3. The sodium ions move through a co-transporter and transport glucose alongside it into the cells

Punchy Points

1. Glucose moves in with sodium into the epithelial cell

2. Via co-transporter

3. Sodium removed by active transport

4. From cell into blood

5. Maintaining concentration gradient of sodium between lumen and epithelial cells

6. Glucose moves into blood

7. By facilitated diffusion