Question

Please choose any of these 4 topics and answer the questions that they ask. You only need to choose one.

Consider the two ways we regulate thirst. Why are the two types of thirst seemingly indistinguishable to an individual (think of common pathways/structures in the nervous system). In essence, name the 2 types and how they differ, as well as what they have in common.

Explain and contrast the following theories of motivation: 1) Drive Theory; 2) Incentive Theory; 3) Instinct Theory; 4) Arousal Theory. You do not need to do it in this order. Come up with an example of a behavior (like the candy bar I talked about in the lecture) and explain how each of these theories would be explained.

How important is the sense of taste in our lives? How does taste govern what we eat, what we want to eat, and how much we eat? What do the 5 taste senses tell us about the nature of the food.

The tastes are: Sweet, Salty, Sour, Bitter, and Umami. Explain why we may get certain cravings for these types of food.

What are the most common forms of eating disorders? How do they differ? What do they have in common (how are they similar)? Also, how are they related to other psychological disorders? Discuss their various causes, and the physiological mechanisms that produce them.

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Answer 1

Consider the two ways we regulate thirst.

Following are the two ways we regulate the thirst:

1. Osmomatric Thirst

2. Volumetric Thirst

Why are the two types of thirst seemingly indistinguishable to an individual. In essence, name the 2 types and how they differ.

1. Osmomatric Thirst

Osmomatric thirst is a kind of thirst in which three detectors are responding to change in the concentration of the interstitial fluid that surrounds them. Osmosis means the movement of water through semipermeable membrane from a region of low solute concentration to one of high solute concentration.
Semipermeable membrane -- A membrane that allows some but not all molecules to pass through osmomatric thirst produce by an increase in the osmomatric pressure of the inter-stitial fluid relative to intra-cellular, thus produce cellular dehydration.
Osmosis receptors -- Neurons that detect in the solute concentration of the intra-stitial fluid that surrounds in and are responsible of osmomatric thirst and located in the region of the anterior of hypothalamus.
Thirst osmomatric -- Thirst produce by increase in the relative osmatic pressure of extra cellular fluid which results from loss of cellular fluid.
Thirst volumetric -- Thirst produce by decrease amount of extra cellular fluid in the body.

2. Volumetric Thirst

This type of thirst is associated with the decrease volume of the blood or blood plasma or decrease in intra vascular volume and it occur mostly through evaporation or through loss of blood, vomiting and diarrhea.
Receptors of kidney -- These are the receptors which controlled the secretion of Angiotensin.
Angiotensin is a peptide hormone that constrict blood vessels causes the retension of sodium and water produce thirst and salt appetite.
Receptors of Heart and Blood -- These are also known as arterial baror receptors. These are associated with the volumetric thirst lie within the heart which contains sensory neurons when the blood plasma fall in the vessels. These receptors detect the change and stimulate processes.

What they have in common.

The concept of receptors is common in both kind of thirsts. For example, in osmomatric thirst there are osmosis receptors and in case of volumetric thirst there are receptors such as kidney and heart.