Question

1. What is a second-messenger system? Why is it necessary for amino acid-based hormones to use such a system? Why does it allow amino acid-based hormones to only act where they are supposed to?

2. Which hormones does the pituitary gland make? Which other glands are directly controlled by the pituitary’s hormones? Why is it beneficial that so many glands are controlled by a single organ attached to the brain?

3. What is Hypoxia Inducible Factor (HIF)? What kind of situations would cause this factor to be released? Where is produced? Why would this organ care about hypoxia?

4. What are the primary components of blood? What does each component do? What would you find dissolved in blood, and why are there so many things dissolved in the blood in the first place?

5. Where in the body is the highest oxygen concentration? The highest carbon dioxide concentration? Why is oxygen so high there? Why is carbon dioxide so high in the other location?

6. What are the three types of capillaries? What kind of functions would each type be used for?

7. What are the major anatomical differences between arteries and veins? What are the major physiological differences between arteries and veins? How do the physiological differences explain the anatomical differences?

8. What is the difference between the systemic and pulmonary circuits? How is blood moved through each circuit?

9. How does the body use vasoconstriction and vasodilation to control blood pressure? Why does the body use arterioles instead of larger arteries or veins to control blood pressure?

10. What region of the brain can send signals that alter the heartrate? Why would that region, as opposed to the other three regions, have developed that ability?

11. What is a baroreceptor? Where are some of the locations where baroreceptors are located? Why would the brain need to monitor the body this way?

12. What hormones are used to control blood pressure? How do they cause BP to increase or decrease?

13. What are anatomical differences between lymphatic vessels and blood vessels? What are the physiological differences between lymphatic vessels and blood vessels? How do the physiological differences explain the anatomical differences? Are lymphatic vessels more like arteries or veins, and why?

14. What is the difference between a primary and secondary lymphoid organ? What are the two primary lymphoid organs, and what are the major secondary lymphoid organs?

15. What are the Mucosa-Associated Lymphoid Tissues (MALT)? Where are they found, and what do they do? Why would lymphoid tissues be beneficial in these locations?

Answer 1

second messenger system:

second messenger system are intracellular signalling molecules released by the cell in response to exposure to extracellular signalling molecules ie the first messenger system.

The secondary messenger system triggers physiological changes such as proliferation , differentiation, migration , survival and apoptosis.

Most hormones are aminoacid based hormones .They can range from simple modified aminoacids to polypeptides to proteins .

The remainder are steroids , which are synthesized from cholesterol.

for example :

Cyclic AMP( secondary messenger) act on epinephrine , norepinephrine , Glucagon ,LH,FSH, TSH , calcitonin.

Thyroid hormone (lipid soluble) all amino acid derived hormones bind to cell membrane receptors that are located at least in part ,on the extracellular surface of the cell membrane.

Therefore ,they do not directly affect the transcription of target genes, but instead initiate a signalling cascade that is carried out by a molecule called a second messenger.