Question

The example below is a homeostatically regulated system.

Decrease in blood volume ? triggers volume receptors in atria (heart) ? Signals hypothalamus (brain) to synthesize a neurohormone ? Neurohormone is released ? Kidneys increase number of water pores in renal cell membranes ? increases blood volume

* Reminder: You don’t need to know anything about water regulation, use your fundamental knowledge regarding homeostatically regulated systems

1.) In this system presented identify the following variables and explain what is the function of each (said another way: what is the purpose of a sensor and so on)

a.) Homeostatically regulated variable (no need to explain function):

b.) Sensor:

c.) Integrator:

d.) Effector:

2.) In this example, is the increase number of water pores in renal cell membranes a cause or effect of neurohormone being released, Also, is it indirectly or directly related? Explain.

Answer 1

Answer 1.

Homeostatically regulated variable- blood volume

Sensor- hypothalamus of brain

Integrator- neurohormone

Effector- kidneys

Explanation :

Homeostasis refers to the change in the internal environment with respect to the external surroundings. Due to the drop in the pressure, the volume of the blood decreases which needs to be maintained.

Whatever gets processed or is performed in our body is due to the activity of the brain. It is the supreme commander of the body which takes up the decision to perform all the functions Brain being very important cannot leave its place hence has chosen for an intermediate molecule which carries the information from the brain to the effectors.

The ultimate action goes to the target molecules and here they are kidneys which needs to perform an action.

Answer 2.

Increase in the number of water pores in the renal cell membranes is an effect of the release of the neuro hormone from the hypothalamus of the brain.

Since there was a significant drop in the glomerular filterate due to processes like constriction of the afferent arteriole, or the dilation of the efferent arteriole and many others; these impacted the kidneys and led the significant drop in the blood volume happen. These changes in turn were detected by the brain which responded by signaling the kidney cells to increase the number of the pores so as to increase the blood pressure and hence the volume.

The complete process mentioned above forms a part of the feedback mechanism . All the aspects and attributes are interdependent on each other. Hence this is directly dependent on each other