P1 - Breathing mechanics

Question 1

Describe inspiration at rest, what muscles? causes what?

Answer 1

At rest the external intercostal muscles contract and the diaphragm contracts and flattens. which lifts the rib cage and sternum up and out. As this happens the volume inside the thoracic cavity and space inside the lungs increases. This causes a reduction in pressure in the lungs compared to outside the lungs. The air then rushes form an area of high pressure to low pressure so air rushes in the lungs

Question 2

Inspiration during exercise

What muscles? what movement? How is volume, pressure and air affected?

Answer 2

The diaphragm contracts and flattens with greater force and the external intercostal muscle contract with greater force. Additional muscles such as the sternoilcolistd are recruited. All these muscles together lift the rib cage up and further out then at rest. This increases the volume of the thoracic cavity and space inside the lungs more than at rest. This causes a greater decrease in pressure in the lungs compared to outside the lungs than at rest. so more air enters the lungs so increased air inspired.

Question 3

Expiration during rest.

What muscles causes what movement?

Answer 3

Is a passive process. The external Intercostals relaxes and the diaphragm relaxes so the ribs and sternum drop down and in. Thoracic cavity reducs. Pressure in the lungs increases as the space is smaller. Gasses moves from high pressure to low pressure. so air goes out.

Question 4

Expiration during exercise

What muscles? what movement? How is volume, pressure and air affected?

Answer 4

Becomes active process. During expiration the internal intercostals contract to pull the rib cage down and in. rectus abdominals contract to force the diaphragm up faster and harder. This reduces the volume of the thoracic cavity causing an increase in pressure in the lungs meaning air is forced out more than at rest. as gasses move from an area of high pressure to a area of low pressure.

Question 5

What is the RCC(respiratory control centre)?
where is it?
what are the parts off it?

Answer 5

The RCC (respiratory control centre) is located in the medulla oblongata and is responsible for regulating respiration (breathing) at rest and during exercise. 
Inspiratory Centre (IC) - controls the taking in of air and therefore oxygen which can be sent to the muscles.
Expiratory Centre (EC) -  controls the exhaling of air and therefore the release of c02 from the body during exercise as at rest it is not needed.

Question 6

how does the body increases rate and depth of breathing in response to exercise? and why? and what does what? (receptors, nerves, tells what what?)

Answer 6

thermoreceptors, chemoreceptors, Baroreceptors, detect changes in the body. Such as when there is an increase in acidity in the body they send signals to the rcc which makes the ic increase breathing rate by sending signals to the intercostal nerve to contract the external intercostals and the phrenic nerve to increase the force the diaphragm contracts with to greater increase the volume of the thoracic cavity as breathing rate needs to be increased to remove c02 and oxygen is needed for the working muscles.

Question 7

Where does the intercostal nerve send impulses too?

What about the phrenic nerve?

Answer 7

intercostal nerve goes to the external intercostals

phrenic nerve goes to the diaphragm