Resp Phisiology Mechanism

Question 1

Name the gas laws involved in respiratory system

Answer 1

Dalton’s law-
Fick law of diffusion
Boyle’s law
Ideal gas law

Question 2

Explain Dalton’s law

Answer 2

Each gas in a mixture of gases will exert a pressure independentof other gases present
partial pressure of oxygen 760mm hg x21% = 160 mm Hg

Question 3

Fick’s law of diffusion

Answer 3

The flus or diffusion of gases is directly proportion to partial p gradient

Question 4

Factors affecting diffusion

Answer 4

• surface area
• partial pressure gradient - most important
• membrane permeability and thickness- diffusion distance
• capillary transmit time - amount of time for the interaction
• ventilation perfusion ratio

Question 5

Gradient factor (partial pressure gradient)

Answer 5

Particles move from a High partial pressure in the lungs to a low partial pressure in the capillaries

Question 6

Asthma- gradient

Answer 6

Partial pressure decreases

Question 7

Membrane thickness

Answer 7

The thicker the lung the slower the diffusion eg silicosis, fibrotic lung disease

Question 8

Fluid in interstitial space

Answer 8

Decreased diffusion eg pulmonary edema due to heart attack

Question 9

Membrane surface

Answer 9

Low surface area low diffusion e.g smokers

Question 10

Solubility of gases

Answer 10

02 much less soluble than carbon dioxide

Question 11

Capillary transit time

Answer 11

When decrease - diffusion decrease

Question 12

Ventilation to perfusion ratio

Answer 12

High v/q =higher oxygen and Carbon dioxicel diffusion PE

Low v/q- lower diffusion ASTHMA

Question 13

What is alveolar ventilation

Answer 13

Air main in and out of the lungs 4L/ min

Question 14

Alveolar perfusion

Answer 14

Pulmonary blood flow 5L/min

Question 15

V/q average

Answer 15

0.8 L/min

Question 16

V/Q apex and base ratio

Answer 16

Apex-0.25

Base-0.8

Question 17

Boyle’s law

Answer 17

The relationship between gas pressure and volume is inversely related when increasing volume (alveoli) decrease pressure, increasing pressure (bronchi) decrease volume

Question 18

Inspiration (inhalation)

Answer 18

1. Inspiratory muscles contract (diaphragm) descends and rib cage rises
2. Thoracic cavity volume increases
3. Lungs stretches intrapulmonary-volume increase
4. Intrapulmonary pressure drops to 1 mm Hg
5. Air moves down pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric pressure)

Question 19

Muscles involved during primary respiratory muscles during inspirations

Answer 19

1. External intercostal muscles and diaphragm

Question 20

Accessory muscles during inhalation

Answer 20

SCM, scalene, pectoralis minor, serratus anterior.

Question 21

Expiration

Answer 21

1. Inspiration muscles relax and rib cage descends ( diaphragm rises)
2. Thoracic cavity volume decreases
3. Intrapalmonary pressure rises to above 1mm hg
4. Air flows out following pressure gradient

Question 22

Quiet breathing (eupnea)

Answer 22

Active inhalation and passive exhalation

• diaphragmatic breathing or deep breathing = dominated by diaphragm
• costal breathing or shallow breathing = dominated by rib cog movements

Question 23

Elastic rebound

Answer 23

When muscles of inhalation relax

• elastic components of tissues recoil
• diaphragm and rib cage turn to original position

Question 24

Forced breathing (hyperpnea)

Answer 24

• involve active inhalation and exhalation

* Assisted by accessory muscles