Exam 2

Question 1

What are the different mechanisms in our bodies concerning eating, drinking, and sleep?

Answer 1

Mechanisms to DETECT variables outside of acceptable range Mechanisms to BRING BACK to acceptable range

Question 2

What is the difference between homeostatis and allostasis?

Answer 2

Homeostatis states there is a single point tuning system… Allostatic states that

Question 3

I am hot and I sweat to cool down… what type of mechanism is this?

Answer 3

Homeostasis

Question 4

You are too hot so you sweat to cool of your body, which might leave you dehydrated, so you also reduce urine output, constrict blood vessels to maintain blood pressure, begin to search for and consume water… What type of mechanism is this?

Answer 4

Allostasis - We are more allostasis than the simple homeostasis explanation. All the systems are participating in this mechanism.

Question 5

What are the 5 things that need to be maintained at specific levels?

Answer 5

-Temperature +Going 5 degrees up/down, we are near death -Oxygen levels -Ionic concentrations +(Neural transmission) -Nutrient availability – glucose, proteins, fats -Hormone levels

Question 6

What is the function of the regulatory systems?

Answer 6

The system that monitor variables (like temperature; etc) and initiations of mechanisms.

Question 7

Negative feedback system is a ____________ system. It ___________ these variables and _________ of mechanisms

Answer 7

Negative feedback system is a REGULATORY system. It MONITORS these variables and INITIATIONS of mechanisms.

Question 8

What happens when variables deviate from the normal range of levels?

Answer 8

Deviation from the normal range prompts the regulatory systems to signal the brain to 1) conserve/expend the variable in question, and 2) instigate behaviors that will bring the variables back into acceptable limits

Question 9

How is our regulatory system similar to a thermostat? *4 main components of a regulatory system

Answer 9

The components of the regulatory system has to have the following: 1. System variable (what’s being monitored - so like air temperature in room). 2. Set point (optimal value that system variable needs to be in - temperature we set the thermostat to, 75 degrees). 3. Detector (monitors system variable and signals when the system variable moves away from set point - thermostat’s temperature gauge, and when the temp. gets too cold or too hot.) 4. Correctional mechanism (heater or AC depending on the detector).

Question 10

Explain what negative feedback is. What types of variables are affected by the negative feedback loop?

Answer 10

Negative feedback is a process in which the response of the correctional mechanism is what ultimately turns it off (the activity of the turning off of the “heater” or “AC” after achieving the right temperature). Temp, oxygen, heart rate…

Question 11

What is the process that is activated to restore the system variable to the set-point by monitoring the amount of resources or set of time, the correctional mechanism has made available.

Answer 11

Satiety mechanisms : A process that causes cessation of a signal (ie hunger or thirst) that is produced by adequate and available supplies to restore system variable to the set point (ie nutrients or water). What’s being monitored is how long the correctional mechanism has been active (not monitoring the system variable like the negative feedback).

Question 12

What are the examples of the 2 regulatory systems pertaining to thirst? What is the difference between the two?

Answer 12

Negative feedback -Decrease in bodily fluids (from sweat), and detectors noticed you have less water than optimal range. Then you initiate the correctional mechanisms (drinking). Water goes into stomach, bloodstreams, and into fluid compartments. Process is slow. Satiety- you start drinking water, you feel stomach filled with water inhibits the fluid balance. The difference is in the time dynamic - The negative feedback process of getting water into bloodstream into cells takes a lot longer than “feeling” the fullness.

Question 13

Which responses are more likely to be regulated by satiety signals? Why? Temperature or Thirst

Answer 13

Responses that take longer for correctional mechanism to make an impact on the system variable are usually regulated by satiety systems such as Thirst. We could overdose on water, so we need a quick signal like satiety mechanism.

Question 14

Where is water stored in our bodies?

Answer 14

Intracellular fluid (in cells) (67%) Extracellular fluid (33%) Cerebrospinal fluid (

Question 15

How much of our total volume of water are in the intercellular cells of our bodies?

Answer 15

2/3 or 67%

Question 16

What type of fluids does extracellular and intracellular fluid have? Explain how the concentration of the cells should be…

Answer 16

Extracellular fluid contains different solutes than intracellular fluid. The two fluid types are isotonic, containing equal concentrations of solutes. Even though concentration of the solutes (dissolved ions) are different between the inside and outside of cell, the TOTAL amounts of solutes must be add up to equal, or isotonic. Ex) There should be 100 ml in ALL compartments…

Question 17

What makes up isotonic fluids?

Answer 17

Solutes and electrolytes (or ions). SOLUTES are molecules dissolved in water. Molecules dissolved inside of cells are in different concentrations dissolved in the outside of our cells. Molecules dissolved in the water with a charge are called ELECTROLYTES or IONS

Question 18

Why is maintenance of isotonicity important?

Answer 18

It determines where the fluids go. Water behaves like diffusion - goes from high concentration of water to low concentrations… This is OSMOSIS.

Question 19

Define Osmosis:

Answer 19

Concentration of solutes that determine movement of water. Similar to Diffusion.

Question 20

Why do we say that the fluid compartments are semi-permeable membranes? What does this have to do with water?

Answer 20

Water can pass through cell membranes because they are non-polar, but ions cannot pass through.

Question 21

Why does water move through cell membranes?

Answer 21

To equalize solutes.