Lesson 1: An overview of homeostasis

Question 1

What is negative feedback?

Answer 1

Negative feedback loops occur in your body through its own internal controller for maintaining temperature, pH, hormone levels, blood sugar and other internal variable levels at homeostasis, which is the optimal internal state at which your body operates best.

Question 2

What is positive feedback?

Answer 2

With negative feedback, the output reduces the original effect of the stimulus. In a positive feedback system, the output enhances the original stimulus. A good example of a positive feedback system is child birth. During labor, a hormone called oxytocin is released that intensifies and speeds up contractions.

Question 3

Describe several aspects of the internal environment that need to be regulated by homeostatic processes

Answer 3

Characteristics of internal environments such as temperature, pH, water levels, cellular activity, and presence of food and wastes need to be regulated by homeostatic processes.

Question 4

What is meant by the term homeostasis?

Answer 4

its the combined effort of many parts of the body working to maintain a stable internal environment. The stable point reached through the process of homeostasis is the result of a dynamic equilibrium

Question 5

What are the 3 components of a homeostatic control system?

Answer 5

• a monitor (aka sensor)
• a coordinating centre
• a regulator (aka an effector)

Question 6

Thermoregulation: Ectotherms

Answer 6

Ectotherms: their metabolic rates on dependent on external temperatures and other external elements.

Question 7

Endotherms

Answer 7

• mammals, humans, and birds are endotherms
• they are able to maintain a constant internal body temperature regardless of their surroundings
• they can generate internal heat from organs such as the kidney and liver.
• when external temperature drops they can increase their rate of cellular respiration to genertae internal heat

Question 8

Thermostat

Answer 8

its located in a region of the brain called the hypothamulus.
- for humans it is set at 37 degrees celcius

Question 9

What is thermoregulation?

Answer 9

The maintenance of body temperature within a range that enables cells to function efficiently is called thermoregulation. An example is how the body reacts to heat stress. In this case, blood vessels dilate so that excess heat may be released. This causes the skin to become red. In addition, the production of sweat and its resulting evaporation can remove heat from the body.

Question 10

Compare the air conditioning system and thermostat in a building to the cooling system in your body.

Answer 10

both systems have monitors, regulators, and a coordinating centre. In the building, the coordinating centre is the buildings thermostat, where the desired temperature is set. In the human body, that role is played by the hypothamulus in the brain. The monitors in the building are the rooms thermometers, whereas in the body, they are the nerves. The regulator in the bulding is the air conditioning unit that genertaes cold air.In the human body, one regulator is the sweat glands, which release water onto the surface of the skin, and this cools the skin through evaporation. Both systems work on a negative feedback principle to prevent small changes from becoming too large.