Biology 8 Lesson 14: Leukocytes – Immunity
1. Summary of theory
1.1. Main activities of white blood cells
a. Structure of white blood cells
– White blood cells are nucleated cells, large in size: 8-18 µm in diameter, much less numerous than red blood cells (7000 – 8000mm3), with no definite shape.
- Neutrophils, 10 µm in diameter, red-brown granules.
- Eosinophils, about 8-12 µm in diameter, red-pink granules.
- Basophils, 8-12 µm in size, purple-green granules.
b. The structure of antigen-antibody
Antigen: A foreign molecule capable of stimulating the body to secrete antibodies. Like venom of bees, snakes, substances on the surface of bacteria, viruses, etc.
Antibodies: are protein molecules secreted by the body against antigens.
Mechanism: Key and padlock.
c. Main activity of white blood cells
White blood cells participate in the body’s defenses by:
Phagocytosis is the process by which white blood cells capture and swallow bacteria into the cell and then digest them.
B cells fight antigens by secreting antibodies, which inactivate the antigens.
– T cells have destroyed body cells infected with bacteria and viruses by recognizing, contacting and secreting specific proteins that dissolve the infected cell membrane and destroy the infected cell.
Immunity is the ability of the body not to contract an infectious disease despite living in an environment with pathogenic bacteria.
There are two types of immunity: natural immunity and artificial immunity.
Natural immunity: the body’s ability to fight off disease (caused by antibodies).
- Innate immunity.
- Infection immunity.
+ Artificial Immunity: is to create the body’s immunity by vaccines.
2. Illustrated exercise
What defenses do white blood cells create to protect the body?
White blood cells form three defenses to protect the body:
- Phagocytosis is performed by neutrophils and macrophages.
- T lymphocytes destroy body cells infected with bacteria and viruses by recognizing, contacting and secreting specific proteins that dissolve the infected cell membrane and destroy the infected cell.
- B lymphocytes fight antigens by secreting antibodies, which then inactivate the antigen.
3.1. Essay exercises
Question 1: How are the body’s cells protected from infectious agents (bacteria, viruses, etc.)
Verse 2: What diseases do people usually vaccinate (immunize) for children?
Question 3: What diseases are you immune to from a previous illness and to which diseases from vaccinations (vaccinations)
3.2. Multiple choice exercises
Question 1: Which of the following are secreted by T lymphocytes?
A. Toxic Protein
Verse 2: Which of the following cell types in the human body is capable of secreting antibodies?
A. Limpo CLOSED
B. Limpo T
Question 3: The type of leukocytes involved in phagocytosis are:
A. Limpho T
B. Limpho B
C. Neutral and mono
D. All of the above.
Verse 4: For the following types of white blood cells:
3. Acidophilic white blood cells
What are the types of leukocytes that do not participate in phagocytosis?
Question 5: In the immune activity of the human body, the combination of which of the following pairs of factors occurs by a key and lock mechanism?
A. A. Antigen – antibody
B. Antigen – antibiotic
C. Antibiotics – antibodies
D. Bacteria – Toxic Protein
After completing this lesson, you should:
- List the main functions of white blood cells in the body.
- State the concept of immunity.
- Distinguish between natural immunity and artificial immunity.