1. Hormones are chemical signals that are secreted into the circulatory system and communicate regulatory messages within the body.
2. A hormone may reach all parts of the body, but only specific target cells respond to specific hormones. 3. The body has two longdistance regulating systems. Which involves chemical signals by hormones? endocrine system
4. What is the other major communication and control system? nervous system
5. Endocrine gland is ductless and secrete hormones directly into surrounding fluid (ex: thyroid gland). Exocrine gland has ducts and secrete substances onto body surfaces or into the body (ex: tear ducts).
6. Compare the action of each of the following, and give an example. hormones: secreted from the endocrine glands and travels through the body via fluids to target cells local regulators: molecules that travel a short distance and reach target cells through diffusion, ex: blood pressure, contractions neurotransmitters: chemical secreted by neurons that travels across the synapse to the target cell pheromones: chemicals used to communicate with others
7. These figures show five different types of signals. Label and explain each one.
8. The receptors for lipid soluble hormones are found on the plasma membrane.
Transmembrane proteins have a receptor on the extracellular side of the cell.
9. Where are the receptors for the watersoluble proteins found? Explain this difference for the two types of hormones. can’t get through the membrane
Mode of Travel in bloodstream Location of receptors Examples
change synthesis of mRNA lipidsoluble
diffuse across membrane of endocrine cells
bind to transport proteins intracellular
changes in gene transcription 11. What endocrine gland secretes epinephrine? adrenal gland
12. Epinephrine is secreted when stressed. When it reaches liver cells, it binds to a G proteincoupled receptor in the plasma membrane. It triggers a cascade of events, leading to cell releasing glucose into bloodstream.
13. Use the following figure to explain the signal transduction pathway for epinephrine.
14. Explain the action of this steroid in the following figure.
binding with receptor activates transcription of a gene for a certain protein.
15. The effects brought on by a hormone can vary if the target cells differ in the mlcs that receive, transduce, or respond to that hormone. vary in receptors or signal transduction pathways. 16. Viagra activates an enzyme that relaxes neighboring smooth muscle cells, which improves blood flow to tissues.
17. Prostaglandins contribute to menstrual cramps in females because they stimulate smooth muscles of uterine cell wall to contract.
18. A negative feedback loop occurs in a loop in which response reduces initial stimulus
19. Complete the following chart for this pair of antagonistic hormones.
when blood glucose rises above a set point, the release of insulin triggers uptake of glucose from the blood, decreasing the blood glucose concentration
when the blood glucose drops below the set point, the release of glucagon promotes the release of glucose into the blood
20. Use this figure to explain the control of blood glucose by insulin and glucagon.
21. Diabetes mellitus is caused by a deficiency of insulin or a decreased response to insulin in target tissues. Blood glucose levels rise, but cells can’t take up enough glucose. Fat becomes main substrate for cellular respiration.
22. Type 1: autoimmune disorder in which the immune system destroys the beta cells of the pancreas. usually appears in childhood, destroys ability to produce insulin.
Type 2: failure of target cells to respond normally to insulin. insulin is produced, but target cells fail to take up glucose from the