Question

1. How do parasympathetic neurons in the medulla respond to increased blood pressure?
2. Which stimulus is detected by a chemoreceptor?
3. What hormone is released to decrease blood pressure?
4. Sheena's B lymphocytes (B cells) produced antibodies to protect her about 3-5 days after she was exposed to a virus. What type of immunity do antibodies provide?
5. What should NOT elicit an immune response in your own body?
6. What initiates T cell activation?

Answer 1

1.Baroreceptor are mechanoreceptors or stretch receptors which gets activated when there is increase in blood pressure which leads to stretching of blood vessel. These signal will be passed to solitary nucleus in medualla. This will cause the stimulation of vagal nuclei and parasympathetic nervous system is activated. The vasomotor center will be depressed.The final effect is decrease in heart rate and blood pressure.

2. Chemoreceptors will detect chemicals such as carbon dioxide and oxygen as well as change in pH.

3. Atrial natriuretic peptide (ANP) reduce blood pressure. It is produced by atrium and cause vasodilation. It also stimulates excretion of Na and water by kidney.

4. Adaptive immunity

5. Immune system, which includes several immune cells as well as proteins such as antibodies, compliment system, cytokines etc should not react against own body. Antibodies, when it attack own cells can lead to autoimmune disorders.

6. Both CD4 helper T cell and CD8 cytotoxicT cell are activated when it binds to antigen which is held in MHC ( major histocompatibility complex) in antigen presenting cell. CD8 will bind to MHC class 1 and CD4 to MHC class 2.