Question

a. John has started to climb a steep flight of stairs, and keeps climbing, and (phew!) climbing…

i. What happens to his breathing rate, heart rate, and blood pressure?

Blood pressure is a regulated variable. Increasing blood pressure increases blood flow, which increases the rate of oxygen and nutrient delivery to cells. At rest, muscles have a lower metabolic rate and need for oxygen and glucose than they do during exercise. So, the set point of blood pressure changes depending on whether you are resting or exercising.

Here’s how the body “knows” to increase blood pressure: neurons in your carotid arteries recognize increasing CO2 and lactic acid produced by the increasingly active muscles. Those neurons send a message to the brainstem. The brainstem sends a message (via neurons) to the heart and smooth muscle of arteries. The heart increases its rate and strength, and arteries constrict, which increases blood pressure.

ii. How do these changes help him function in his new condition of exercise?

iii. How is this an example of homeostasis?

iv. Identify the SENSOR, CONTROL CENTER, AND EFFECTOR in this system as explained.

Answer 1

Answer 1 - as John is climbing the stairs is breathing rate heart rate and blood pressure all of them increases .

(In order to meet demands of exercising muscles the heart needs to pump more and more blood to the lungs, and lungs need to work more by increasing the respiratory rate so that more oxygen can be delivered to the exercising muscles)

Answer 2 - increase heart rate, blood pressure and breathing rate all of them have shown to acclimatize to the new state of the body. Since the demand of oxygen has increased and now exercising muscle have a higher metabolic rate and need oxygen and glucose during exercise the set point of the blood pressure changes.

Answers 3- homeostasis means same or steady , is is a self regulating process by which the body register changes in order to maintain is table and a constant internal environment that is best for survival. In this case Jones lungs and heart had to work in order to meet the increase oxygen in glucose demand and exercising muscles so this is an example of a homeostasis.

Answer 4 - the sensor baroreceptors present in carotid arteries and aorta.

The controller is the brainstem , Benson controls depth of respiration and increases respiratory rate .

Effector is the respiratory muscles and heart muscles which work in order to meet the excess demand