17- anatomy of ventilation

Question 1

What is Boyle’s Law?

Answer 1

Pressure is inversely proportional to volume. So if volume decreases pressure will increase

Question 2

When does air enter the lungs? considering boyle’s law?

Answer 2

When the atmospheric pressure is greater than the intrapulmonary pressure

Question 3

What changes in the lungs to increase or decrease thoracic volume?

Answer 3

1. Transverse diameter
2. Vertical diameter
3. Anterior-posterior diameter

Question 4

How does the anterior-posterior diameter change during respiration?

Answer 4

At rest the ribs slant sloping downwards. When breathing in the ribs are straight out and sternum is pushed forwards so greater anterior- posterior diameter

Question 5

How does the transverse diameter change during inspiration?

Answer 5

Many ribs are lowest at the middle so if middle of rib rises, it moves away from the midline of the body. chest wider. Bucket handle thing.

Question 6

What is the pressure in the pleural cavity? What function dos this have?

Answer 6

Intrapleural pressure= -4 mmHg. Prevents the lungs from collapsing completely

Question 7

What kind of process is inspiration?

Answer 7

An active process

Question 8

Which muscles aid quiet inspiration?

Answer 8

1. Diaphragm (75%)
2. External intercostals (25%)

Question 9

Which muscles aid forced inspiration?

Answer 9

1. Pectoralis- minor and major
2. Scalenes
3. Serratus anterior
4. Sternocleidomastoid

Question 10

What kind of process is expiration?

Answer 10

At rest it’s passive, but when forced it’s active

Question 11

Which muscles aid resting expiration?

Answer 11

PASSIVE PROCESS

1. Relaxation of diphragm
2. Relaxation of (external) intercostals

Question 12

Which muscles aid forced expiration?

Answer 12

ACTIVE PROCESS

1. Internal intercostals
2. Abdominal muscles. (obliques, abdominis)

Question 13

What are respiratory centres?

Answer 13

Groups of neurons in the brain stem that send impulses to muscles of ventilation

Question 14

What are the two part of the medullary rythmicity centre?

Answer 14

1. DRG- Dorsal respiratory group
2. VRG- Ventral respiratory group

Question 15

What is the network of neurones in the PONS that effects breathing?

Answer 15

Pneumotaxic area

Influences DRG by regulating the duration of inspiration

Question 16

What are the functions of the 2 parts of the medullary rythmicity centre?

Answer 16

DRG- sets rythm, stimulats muscles of inspiration.

VRG- involved in forced inspiration and expiration

Question 17

What do chemoreceptors do?

What are the categories and where are they found?

Answer 17

Responds to changes in PCO2 (and pH)

Two categories:

1. Central chemorecpetors- In the medulla oblongata.
2. Peripheral chemoreceptors- (In blood vessels)- also called carotid bodies and aortic bodies.