Homeostasis of gas concentrations - Chapter 6.2

HBY

What is the waste product of cellular respiration of all cells?

Carbon dioxide

What do cells need a continuous supply of for cellular respiration?

Oxygen

What is the rate and depth of breathing stimulated by?

Concentration of H+ ions in blood OR very extreme low levels of oxygen in blood

Stimulus for high carbon dioxide concentration

Increase in hydrogen ion concentration, decrease in the pH due to increased carbon dioxide in blood when cells undergo cellular respiration

More carbon dioxide in the blood, carbon dioxide and water will be converted to carbonic acid

Carbonic acid will dissociate to form H+ ions and hydrogen carbonate ions

Receptors

Detected by peripheral chemoreceptors located in the aortic and carotid bodies in the aorta

Detected by central chemoreceptors in the medulla oblongata

Modulator

The respiratory centre in the medulla oblongata acts as the modulator

Effectors and negative or postive feedback (Increase in gas concentration)

More sympathetic nerve impulses relayed to the diaphragm via the phrenic nerve

More sympathetic nerve impulses relayed to the intercostal muscles via the intercostal nerve

Increase in rate and depth of breathing due to increase in intercostal muscle and diaphragm contractions

Hydrogen ion concentration in plasma decreases and less carbon dioxide in the blood and more oxygen taken into the lungs due to negative feedback

Hyperventilation

Rapid, deep breathing can provide more oxygen than required and remove more co2 than necessary

How does breathing in a paper bag help?

Inhale higher concentration of co2

• increase co2 in blood

• reset breathing rate

How does hyperventilation allow a person to stay underwater longer?

due to the loss of Co2 NOT increase in o2 concentration

Syncope

When an individual loses conscinessous from the lack of o2 to the brain before feeling the urge to breathe

Heart rate

number of times the heart beats per minute

Stroke volume

volume of blood forced from the heart with each contraction

Blood pressure

the force with which the blood presses on the walls of the blood vessels

intercostal muscles

muscles between the ribs

diaphragm

muscles that cause air to move in and out of the lungs

separates the thorax from the abdomen