Question

question 19
which of the following is not a characteristic of the endocrine system?
chemical messenger travels a short distance.
effector tissues include virtually all tissues.
receptors are located on the plasma membrane or within the target cell.
all of the above are characteristics of the endocrine system.
question 20
which of the following is a function of glucagon?
promotes the entry of glucose into tissue cells
tends to decrease blood glucose concentrations
tends to increase blood glucose concentrations
converts glucose into glycogen

Explanation:

Question 19

• In the endocrine system, hormones (chemical messengers) are secreted into the bloodstream and can travel long - distances to reach target cells. So, the statement “Chemical messenger travels a short distance” is incorrect.
• Endocrine system has widespread effects as effector tissues include virtually all tissues.
• Receptors for hormones can be on the plasma membrane (for water - soluble hormones) or within the target cell (for lipid - soluble hormones).

• Insulin promotes the entry of glucose into tissue cells and converts glucose into glycogen (glycogenesis), and it tends to decrease blood glucose concentrations.
• Glucagon has the opposite effect of insulin. It acts on the liver to break down glycogen (glycogenolysis) and promote gluconeogenesis (synthesis of glucose from non - carbohydrate sources), thus tending to increase blood glucose concentrations.

Answer:

Chemical messenger travels a short distance.

Question 20