BIO 192 - Worksheet #4

BIO 192 - Worksheet #4
Osmoregulation and Chemical Signaling

1.Animals produce nitrogenous wastes via the breakdown of proteins and nucleic acids. The kinds of nitrogenous wastes excreted depend on the animal's phylogeny (evolutionary history) and habitat. Name the three types of nitrogenous wastes, an organism that excretes each type of waste, and the benefits/costs in producing each kind of waste.

2. Define:
(a) Osmoconformer-
(b) Osmoregulator-

3. Create a graph plotting osmolarity of the environment along the x-axis and osmolarity of the body fluid along the y-axis. Draw lines to represent an osmoregulator and an osmoconformer. (Hint: think about the graph we created for endotherms and ectotherms)

4. Osmoregulation in marine and freshwater bony fish
(a) A marine fish is hypotonic to its environment. Would water flow in or out of the fish? Salt? How can the fish maintain osmotic balance?
(b) A freshwater fish is hypertonic to its environment. Would water flow in or out of the fish? Salt? How can the fish maintain osmotic balance?

5. Match each organism below with its excretory system:
i. Insect
ii. Flatworm
iii. Amphibian
iv. Earthworm

A. Flame-bulb system
B. Malpighian tubules
C. Metanephridium
D. Kidneys

6. Draw a nephron and label the following components: a)Bowman's capsule b)glomerulus c)descending loop of Henle d)ascending loop of Henle e)proximal convoluted tubule f)distal convoluted tubule g)cortex h)outer medulla i)inner medulla. Also, place arrows within the drawing to indicate the direction of movement of salt, water, glucose, potassium, bicarbonate, hydrogen ions, and urea along the entire length of the nephron.

7. Physiology of the nephron and collecting duct
(a)What part of the nephron is the major site for reabsorption? Secretion of two substances takes place here. Why?
(b) The descending limb of the loop of Henle is permeable to _______________, but impermeable to __________________. What happens to the volume/concentration of the filtrate here? Why?
(c)The ascending limb of the loop of Henle is permeable to salts, but not water. What are the two ways that salt passes out of the filtrate for reabsorption? Which takes place in the thin segment? Which takes place in the thick segment?
(d) Which area of the nephron helps maintain homeostasis by fine-tuning the blood composition?

8. You have just finished your first BIO152 exam. With great relief, you and your classmates head off to Lynagh's to celebrate. The next morning, after consuming too many rounds of beer the night before, you have a nice hangover. What most likely is the cause of the copious urination and dehydration that you are experiencing?

9. Describe two types of local signaling that occur inside individuals.

10. What's the difference between endocrine signaling and exocrine signaling?

11. Is the pancreas an endocrine organ or an exocrine organ? Explain.

12. Diabetes
a) What is diabetes? What are some symptoms of diabetes and what is the general cause for these symptoms?
b) What is the difference between diabetes mellitus Type I and Type II?

13. What are the three general kinds of hormones? Where are the receptors for each type located?

14. Indicate if the hormones listed below are produced in the anterior or posterior pituitary:
_____________ ACTH
_____________ ADH
_____________ FSH
_____________ GH
_____________ LH
_____________ Oxytocin
_____________ TSH
_____________ PRL

15. What do the acronyms for each of the following hormones stand for?
ADH=
FSH=
LH =
ACTH =
TSH =
GH =
PRL=

16. What is the cause of gigantism, dwarfism, and acromegaly?