Respiratory Phys I

Question 1

what are the 4 major steps to respiration

Answer 1

1. Ventilation
2. Gas exchange (bw alveoli + pulmonary capilaries)
3. Transport of O2 + CO2 by blood bw lungs and tissues
4. Gas exchange bw bloods + cells across systemic tissue capillaries

Question 2

where does the conducting zone start and end

Answer 2

From trachea to the terminal bronchioles (cilliated for removal of debris)

Question 3

Where is the respiratory zone

Answer 3

From respiratory bronchioles to alveoli

Question 4

What is the alveolar PO2 and PCO2 are determined by

Answer 4

relationship bw alveolar ventilation and pulmonary capillary perfusion (VQ ratio)

Question 5

What is henrys law

Answer 5

at a constant temp the amount of gas dissolved in a given liquid is directly proportional to the partial pressure of that gas

Question 6

What is boyles law

Answer 6

At a constant temp, the pressure and volume of a gas in a system are invesly related

Question 7

During inspiration how does the overall presure change

Answer 7

the diaphragm contracts and expanding the volume of the thoracic cavity (decrease pressure allowing air to come in)

Question 8

During expiration how does the overall pressure change

Answer 8

the diaphragm relaxes and shrinks and the volume of the thoracic cavity increasing overall pressure, expelling air

Question 9

Air pressure inside alveoli during quiet inspiration and quiet expiration

Answer 9

inspiration- less that atmospheric pressure

expiration- greater than atmospheric pressure

Question 10

What is the trans pulmonary pressure gradient

Answer 10

the distending pressure of the alveoli that keeps them open

Question 11

What is the trans thoracic pressure gradient

Answer 11

The pressure that pushes inward on the thoracic wall (neg pressure)

Question 12

What occurs in a pneumothorax and what happens to the pressures

Answer 12

opening to the pleural cavity the allows air to flow into the pleural cavity

-intrapleural, intraalveolar and atmospheric pressure all become equal

Transplural pressure gradient is abolished which leads to collapse of lung

Question 13

What are the steps on inhilation

Answer 13

transpulmonary pressure incrreases = more lung expansion-> decreases intra alveolar pressure

=air pressure in lung is lower than air and air rushes in

Question 14

What are the steps of expiration

Answer 14

transpulmonary pressure decreases - lung volume decreases= air pressure in lungs increases

-The air pressure in lung is higher than atmospheric pressure and air is forced out

Question 15

What does deep inspiration cause/ is caused by

Answer 15

strong contraction of the diaphram + external intercostals + accessory mm

-further increase in thoracic cavity dimensions, more of a drop in intra alveolar pressure

Question 16

What does deep expiration cause/is caused by

Answer 16

active process done by contraction of expiratory mm

-causes decrease in thoracic cavity dimensions and increase intra alveolar pressure

Question 17

What is complience and how does it cause

Answer 17

measure of distensibility of the lungs

-higher complience the easier the lung is to expand at a given transpulmonary pressure gradient (less work required)

Question 18

What is elastance and what are 2 forces that modulate it

Answer 18

opposite of complience (how easily the lungs rebound after being stretched)

• tissue forces
• surface tension forces

Question 19

what is lung elastic forces

Answer 19

arises from the elastin and collagen fibres in the alveolar walls and surrounding the bronchioles (once the distending force is released the tissue springs back

Question 20

What 2 things/diseases impact lung elastic forces

Answer 20

Emphysema- destruction of alveolar walls (reduction of surface area w/ air trapped in lungs)

Pulmonary fibrosis- chronic inflammation leading to scar tissue replacing normal lung tissue

Question 21

what is Surface tension forces

Answer 21

atractive forces between thin liquid molecules lining each alveolus, causes alveoli to collapse

Question 22

What is surfactant and what is it made of

Answer 22

Type II alveolar epithelium (secretes lipid agent that reduces surface tension)

Question 23

Why does infant respiratory distress syndrome due to

Answer 23

production of surfactant is absent or insufficient causing alveoli to collapse

Question 24

How does sympathetic/parasympathetic cause to airway resistance (what does each release + cause)

Answer 24

Symp- adrenaline release-> broncholialation

Para- acH release-> bronchoconstriction

Question 25

What does increased and decreased alveolar CO2 cause

Answer 25

increased CO2-> bronchodialation

Decreased Co2-> bronchoconstriction

Question 26

What is radial traction

Answer 26

traction on the bronchial wall by recoil of alveolar septa

Question 27

What is broncial asthma

Answer 27

imflamatorry disease of airway

-characterized by reversible airflow obstruction and bronchospasm

Question 28

What is chonic bronchitis

Answer 28

inhaled irratants lead to prod of excess mucus

-obstruct airflow

Question 29

What does COPD cause

Answer 29

A chronic inflammatory lung disease that causes obstructed airflow (due to emphysema + chronic bronchitis)

Question 30

What is the importance of neg intraplueral pressure (3)

Answer 30

1. keeps lungs streched
2. Helps respiratory movement
3. Helps venous and lymphatic return against gravity