A&P 2 Exam 1 discussion questions

Roger has been extremely thirsty; he drinks numerous glasses of water daily and urinates a great deal. Name two disorders that could produce these symptoms. How are these symptoms produced by these disorders?

-Type 1 diabetes mellitus due to ability to lead glucose and ketones in urine drawing water from ECF by osmosis causing polyuria (frequent urination) and polydipsia (excessive thirst) from dehydration. -hypertension (High Blood Pressure): adrenal cortex releases more aldosterone which increases amount of salt in urine. as a result, water will follow salt into the urine to be excreted.

Discuss the three ways that hormone release is regulated, giving an example of each.

1) Hormonal - GHRH (growth hormone releasing hormone) hits receptor of anterior pituitary gland cell which stimulates the release of GH (Growth Hormone). 2) Humoral - Increase of glucose in the blood will hit a pancreas cell and stimulate the release of the hormone Insulin to uptake that glucose. 3) Neural - When you're hiking in the woods and run into a wolf, your sympathetic nervous system will synapse with your Adrenal Medulla cells to release epinephrine.

How is the release of glucagon and insulin regulated? Explain what causes the release of each hormone. HINT: Think about negative feedback regulation.

Insulin and glucagon are antagonists in a negative feedback loop that maintains the homeostasis of blood glucose levels. When blood glucose concentration increase above normal levels, beta cells of the pancreas detect the increased concentration and increase insulin secretion, while alpha cells of the pancreas decrease glucagon secretion. Insulin decreases the blood glucose concentration by increasing glucose uptake by cells and storage of fats, amino acids, and glucose. As blood glucose levels fall, insulin secretion is decreased and glucagon secretion is increased.

Why do people with advanced kidney disease commonly become anemic? Why might they also develop poorly mineralized bone? Explain.

Kidneys produce erythropoietin (EPO) which acts on red bone marrow that stimulates production of RBCs. RBCs carry oxygen throughout the body and have a lifespan. Thus, when RBCs" have gone through their lifespan oxygen is not distributed throughout the body due to the lack of new RBCs to replace the inactive RBCs. As a result, one can become anemic.

Explain how blood levels of T3, T4 and TSH would change in a laboratory animal that has undergone a thyroidectomy. Why does this happen?

When there is low levels of T3 and T4, the anterior pituitary releases TSH to stimulate the thyroid gland to release more T3 and T4. However, when the thyroid is removed, TSH does not have a gland to stimulate to produce more T3 and T4. As a result, there is a continuing decrease in levels of T3 and T4 but an increase in levels of TSH.

Explain color vision as clearly and concisely as possible.

color vision is depicted from cones, usually found potently in the center of the retina (fovea centralis). they use a pigment called "iodopsin" which is a combination of retinal and photopsin. There are three different forms of photopsin that each recognize a main category of color or wavelength. The combinations of those wavelengths will construct variable colors.

Explain the differences between high and low pitched sounds, including their respective wave lengths and how they affect the auditory cortex.

lower pitch = longer wavelength; low frequency; travel deeper distance in cochlea high pitch = shorter wavelength; higher frequency; travel shorter distance in cochlea

Which part of the retina produces the sharpest vision when light falls on it? Why? Why is it necessary to look slightly to the side of a dim star in order to see it clearly?

the sharpest vision is produced by light entering the eye and focusing at the center of the retina. The fovea centralis contains mostly cones, which provide us with both color vision and a level of acuity that surpasses the clarity produced by rods. However, rods are better than cones at processing the amount of incoming or available light... so if we're trying to discern where the "halo" of light around a star starts, or to judge the level of light put off by a star, then it would be best to view that star using mostly rods. And of course, the periphery of the retina is where more rods are located, so we should look at a star using some of our peripheral vision.