Neuro psych Quiz 9.1-3 Flashcards
What does negative feedback do?
It reduces discrepancies from a set point
How do poikilothermic (ectothermic) animals regulate their body temperature, if at all?
They move to a location with a more favorable temperature
What is the primary advantage of maintaining a constant high body temperature?
It keeps the muscles ready for rapid, prolonged activity even in cold weather.
If we inserted a probe into the POA/AH and directly heated the area, what if anything would happen?
The animal would sweat or pant
When you have an infection, what causes the fever?
The immune system increases delivery of prostaglandins and histamine to the POA/AH.
Which of he following is the most correct description of a fever?
Fever is one way by which the body fights against bacteria.
If you lacked vasopressin, how would your drinking change, if at all?
You would drink more.
What would happen as a result of adding salt to the body’s extracellular fluids?
Increased osmotic thirst
How does hypovolemic thirst differ from osmotic thirst?
Someone with hypovolemic thirst prefers slightly salty water.
People differ in their likelihood of consuming milk products in adulthood because of what type of genetic difference?
Genetic variants in ability to metabolize lactose
Which of the following describes the relationship between taste and eating?
Taste is neither necessary nor sufficient for eating although it contributes
After surgical removal of someone’s stomach, what mechanism if any can produce satiety?
Distension of the duodenum
When food distends the duodenum, the duodenum releases the hormone CCK. By what peripheral mechanism does it increase satiety?
CCK tightens the sphincter muscles between the stomach and the duodenum.
How does the ideas of allostasis differ from homeostasis?
Homeostasis is a set of processes that keep certain body variables within a fixed range. Allostasis is an adjustment of that range, increasing it or decreasing it as a circumstance change.
What is the primary advantage of maintaining a constant high body temperature?
A constant high body temperature keeps an animal ready for rapid prolonged muscle activity eve in cold weather.
Why did mammals evolve a temperature of 37 C (98.6F) instead of some other temperature?
Animals gain an advantage in being as warm as possible and therefore as fast as possible. However proteins lose stability at temperatures much above.
What are the sources of input to the POA/AH
The POA/AH receives input from temperatures in the skin the organs and the brain including in the POA/AH itself. It also receives prostaglandins and histamines when the immune system detect an infection
How can an animal regulate body temperature after damage to the POA/AH
It can regulate temperature through behavior such as by finding a warmer or cooler place
What evidence indicates that fever is an adaptation to fight illness?
The body will shiver or sweat to maintain its elevated temperature at a nearly constant level. Also, fish, reptiles, and immature mammals with infections use behavioral means to raise their temperature to a feverish level. Furthermore, a moderate fever inhibits bacterial grown and increases the probability of surviving abacterial infection.
If you lacked vasopressin would you drink like a beaver or like a gerbil? Why?
You would have to drink more like a beaver. You would excrete much fluid so you would need to drink an equal amount to replace it.
Would adding salt to the body’s extracellular fluids increase or decrease osmotic thirst?
It would increase osmotic thirst because it would draw water from the cells into the extracellular spaces.
Who would drink more pure water- someone with osmotic thirst or someone with hypovolemic thirst?
Someone with osmotic thirst. Someone with hypovolemic thirst would drink more of a solution containing salts.
What genetic difference is most important for variants in likelihood of drinking milk in adulthood?
It depends largely on a gene that controls the ability to digest lactose, the main sugar in milk.
What evidence indicates that taste is not sufficient for satiety?
Because animals that shamefeed chew and taste their food but do not become satiated.
What evidence shows that stomach distension is sufficient for satiety?
A cuff is attached to the junction between the stomach and duodenum so that food cannot leave the stomach, an animal becomes satiated when the stomach is full.
What are two mechanisms by which CCK increases satiety?
When the duodenum is destended, it releases CCK, which closes the sphincter muscle between the stomach and duodenum. CCK therefore increases the rate at which the stomach distends. Also, neural signals from the intestines cause certain cells in the hypothalamus to release CCK as a neurotransmitter, and as its receptors, triggers decreased feeding.
Why do people with very low insulin levels eat so much?
Those with very low levels, as in type 1 diabetes, cannot get glucose to enter their cells, and therefore, they are constantly hungry. They pass much of their nutrition in the urin and feces.
Why do people with constantly high levels eat so much?
They deposit much of their glucose into fat and glycogen, so within a short time after a meal, the supply of blood glucose drops.
What would happen to someone’s appetite if insulin levels and glucagon levels were both high.
When glucose levels rise, stored glycogen is converted to glucose, which enters the blood. If insulin levels are high also, the glucose entering the blood is free to enter all the cells. So the result would be decreased appetite.
Why are leptin injections less helpful for most overweight people that for mice with the obese gene.
Nearly all overweight people produce leptin in proportion to body fat. However, they have low sensitivity to it.
Name three hormones that increase satiety and one that increases hunger.
1) insulin
2) CCK
3) Leptin
1) Ghrelin increases hunger
Which neuropeptide from the arcuate nucleus to the paraventriculate nucleus is most important for satiety?
Melancortin
In what ways does the lateral hypothalamus facilitate feeding?
Activity of the lateral hypothalamus improves taste, enhances cortical responses to food, and increases secretions of insulin and digestive juices.
In what way does eating increase after damage in and around the ventromedial hypothalamus?
Animals with damage to the ventromedial hypothalamus eat more frequent meals.
In what way does eating increase after damage to the paraventricular nucleus?
Animals with damage to the paraventricular nucleus of the hypothalamus eat larger meals.
Why did the pima begin gaining weight in the mid- 1900s?
They shifted from a diet of local plants that were seasonally available to a calorie rich diet that was available throughout the year.
In one study rats eating the less-caloric yogurt gained more wight than those eating the more-caloric type. What explanation was proposed?
The rats unlearned their usual calibration that more sweets mean more energy and therefore stopped compensation after eating other sweets.
Homeostasis
balanced internal state. Temperature and other biological processes that keep body variables within a fixed range e.g. thermostat
Set point
A single value the body works to maintain
Allostasis
the adaptive way in which the body anticipates needs, depending on the situation, avoiding errors rather than just correcting them.
process by which the body responds to stressors in order to regain homeostasis
