ANSWERS----
8.1 Importance of Endocrine System
1. Define hormone.
- chemicals released by cells that affect cells in another part of the body.
2. (a) Distinguish endocrine and exocrine glands. Give examples of each.
- Endocrine:
chemicals secreted directly into the blood, pituitary, thyroid, and testes.
- Exocrine:
chemicals secreted through ducts, salivary glands, and sweat glands.
(b) Which gland is both?
- pancreas.
3. Copy Figure 7.
4. What is necessary for a particular hormone to trigger an effect on a particular cell?
- cell must have a receptor.
5. Describe steroid and protein hormones. State common examples of each.
- Steroid:
Made of cholesterol (???), fat soluable.
Example: male, female hormones, cortisol
- Protein:
Protein, made up of amino acids, water soluable,
Examples: insulin, growth hormone
6. Why is the pituitary referred to as the master gland? What does it do?
- it controls most other endocrine glands.
- produces and stores hormones.
ANSWERS- 8.2 Hormones That Affect Blood Sugar
1. (a) What are the roles of the two types of cells in the pancreas?
- digestive enzymes
- hormones
(b) Which type of cells produce hormones? Which two hormones are produced here?
- islets of Langerhans
- insulin and glucagon
2. Complete:
Insulin Glucagon
Type of cell / B / AReleased when …. / blood sugar levels rise / blood sugar levels drop
Effect on muscles, liver and other organs / become permeable and
store glucose / causes glucose to be released to the blood stream
3. (a) What causes diabetes?
- insufficient production or use of insulin.
(b) List some symptoms of diabetes?
- sugar in urine, thirsty, lots of urine, low “E” levels (???)
(c) Outline the three types of diabetes?
- juvenile onset – pancreas is unable to produce insulin
- adult onset – insulin production or ineffective use of insulin
- gestational
4. What did Banting and Best succeed in isolating? Who received the Nobel Price for the
discovery of insulin?
- insulin
- Banting and MacLeod (not Best). MacLeod had just donated lab space.
5. (a) Name the two parts of the adrenal gland?
- medulla and cortex
(b) Name the two hormones produced by the adrenal medulla?
- epinephrine and norepinephrine
(c) List five effects of the release of these hormones?
- blood sugar rises
- heart rate rises
- breathing rate rises
- cell metabolic rate rises
- blood vessels dilate
- iris dilates
(d) List three types of hormones produced by the adrenal cortex?
- glucorticoids
- mineralocorticoids
- sex hormones
ANSWERS 8.3 Hormones That Affect Metabolism
1. Name the three glands that affect metabolism?
- thyroid, parathyroid and anterior pituitary gland
2. Name the principle hormone that regulates metabolism?
- thyroxine
3. Explain how low levels of thyroxine can lead to higher levels of fat?
- nutrients are not oxidized as quickly
- the excess blood sugar is converted to glycogen but excess glycogen gets converted into fat
4. What condition is prevented by having a sufficiently high level of iodine?
- goiter
5. The parathyroid glands release parathyroid hormone (PTH) which regulates calcium levels.
(a) What effect does PTH have when calcium levels are low?
- kidneys and intestines retain Ca2+
- calcium is removed from bone
(b) What side effects may occur if PTH is too high?
- removal of too much Ca2+ from bones
- kidney stones
6. Research the cause and symptoms of hypothyroidism and hyperthyroidism.
ANSWERS- (page 383 – Sections # 1 – 5 8.1 and 8.2 questions)
1. Pancreas - insulin
- glucagon
Adrenal - epinephrine
- norepinephrine
- glucorticoids
- mineralocorticoids
- sex hormones
2. Insulin causes liver, muscles to be permeable to glucose, therefore, they store glucose and therefore the level of blood sugar drops.
3. Glucagon promotes conversion of glycogen to glucose, therefore the level of blood sugar drops.
4. Too many carbs leads to increased blood sugar and therefore, insulin release. Liver stores glucose which converts it to glycogen. OR cells store glucose and Blood sugar level drops to normal.
5. Lots of glucose available to fuel muscles for fight or flight.