6.2 Phagocytosis Flashcards
- What is the first line of defence against disease? - What is phagocytosis? - What is the role of lysosomes in phagocytosis?
What is the body’s first line of defence against pathogens?
A Physical or Chemical barrier to entry.
What 3 forms of barrier to pathogens are there?
A protective covering Epithelia covered in mucus Hydrochlorid acid in the stomach
How does a protective covering work against the entry of pathogens?
The skin covers the body surface, providing a physical barrier that pathogens find hard to penetrate.
How does epithelia covered in mucus work against the entry of pathogens?
In the lungs, pathogens stick to this mucus, which is then transported away by cilia and swallowed into the stomach.
How does hydrochloric acid in the stomach work against the entry of pathogens?
Most of the enzymes of the pathogens are denatured in the low pH and the organism is killed.
What is the body’s second line of defence against pathogens?
Phagocytosis
What is the process of phagocytosis?
When large particles are engulfed by cells in the form of vesicles formed from the cell-surface membrane
What is the name of the white blood cells that perform phagocytosis?
Phagocytes
What is the first step of phagocytosis?
Phagocytes attach themselves to the surface of the pathogen.
What is the second step of phagocytosis?
The phagocytes engulf the pathogen to form a vesicle known as a phagosome.
What is the third step of phagocytosis?
Lysosomes fuse with the phagocyte.
What is the fourth step of phagocytosis?
Enzymes from the lysosomes break down the pathogen.
What is the fifth step of phagocytosis?
The soluble products from the breakdown of the pathogen are absorbed into the cytoplasm of the phagocyte.
What are all 5 steps of phagocytosis?
- Phagocytes attach themselves to the surface of the pathogen.
- The phagocytes engulf the pathogen to form a vesicle known as a phagosome.
- Lysosomes fuse with the phagocyte.
- Enzymes from the lysosomes break down the pathogen.
- The soluble products from the breakdown of the pathogen are absorbed into the cytoplasm of the phagocyte.
