Respiratory

Question 1

describe the role and constituents of surfactant

Answer 1

surface active lipoprotein secreted by type 2 pneumocytes. The lipids have both a hydrophobic and hydrophilic region. Its role is to reduce surface tension allowing for symmetrical inflation of the alveoli.

Question 2

what is negative pressure

Answer 2

pressure below atmospheric pressure

Question 3

what is positive pressure

Answer 3

pressure above atmospheric pressure

Question 4

define airway resistance

Answer 4

= 1/radius to the power 4

Question 5

lateral traction

Answer 5

the elastic tissue linking the outside of the airways to the alveolar tissue helps the alveoli to expand during inhalation. It is the ease of expansion

Question 6

transpulmonary pressure

Answer 6

the difference in pressure between the inside and ourside of the lungs. it increases during inspiration- airway radius increases, resistance decreases as the lungs expand.

Question 7

boyles law

Answer 7

p1v1=p2v2

Question 8

partial pressure of a gas

Answer 8

directly proportional to its concentration

Question 9

anatomical dead space

Answer 9

the proportion in inhaled air which does not participate in gas exchange

Question 10

the haldane effect

Answer 10

the more oxygen the blood holds the less carbon dioxide it can hold and vice versa

Question 11

intrapleural pressure

Answer 11

changes in hydrostatic pressre of the intrapleural fluid which causes the lungs to move in and out during normal breathing. an increased intrapleural pressure compresses the small conducting airways and decreases their radii. Thus increased airway resistance

Question 12

neuroendocrine and paracrine factors

Answer 12

can influence smooth muscle- thus influencing airway resistance.

Question 13

where is airway resistance greatest in the lungs?

Answer 13

in the intermediate bronchi

Question 14

Define type 1 respiratory failure and its causes

Answer 14

hypoxemic respiratory failure. low PO2, CO2 can be normal and high. It can be result of fluid in the lungs, pulmonary embolism or collapse of alveolar sacs or airway obstruction.

Question 15

define type 2 respiratory failure and its causes

Answer 15

hypercapnic respiratory failure, High PaCO2. commonly caused by neuromuscular diseases, cardiac failure and emphysema. Commonly causes hypoxemia as CO2 levels in the blood alters pH of the blood too.

Question 16

ventilation

Answer 16

the exchange of air between the atmosphere and the alveoli

Question 17

I neurons

Answer 17

discharge during inspiration, relayed from C3,4,5 and T3,4,5,6 by the phrenic and intercostal nerves respectively innervating the diaphragm and intercostals

Question 18

E neurones

Answer 18

discharge during expiration, relayed from the same areas but causes inhibition of I neurons. E neurons are only excited on forced expiration

Question 19

pneumotaxic centre

Answer 19

may have a role in switching between inspiration and expiration

Question 20

aperneustic centre

Answer 20

controls the speed of inhalation and exhalation

Question 21

forced expiry volume 1

Answer 21

volume of air forcibly expired in one second

Question 22

peak flow rate

Answer 22

the measure of air expired from the larger upper airway (highest rate of air flow out of the lungs)

Question 23

total lung capacity 5900ml

Answer 23

the total volume of air the lungs can hold at maximal inhalation

Question 24

vital capacity 4700ml

Answer 24

the volume of air exhaled after the deepest inhalation

Question 25

residual volume 1200ml

Answer 25

the volume of air remaining in the lungs after maximal exhalation

Question 26

functional residual capacity 2400ml

Answer 26

the Volume in the lungs at end residual position

Question 27

tidal volume 500ml

Answer 27

the volume of air moved into and out of the lungs at resting state

Question 28

expiratory reserve volume 1200ml

Answer 28

the maximum volume of air that can be exhaled after exhalation

Question 29

inspiratory reserve volume 3000ml

Answer 29

the maximum volume of air that can be inhaled after inhalation

Question 30

static compliance

Answer 30

the change in volume of lung for a given pressure

Question 31

dynamic compliance

Answer 31

the compliance of the lung at any given time during actual air movement- during normal breathing

Question 32

compliance

Answer 32

a measure of stretchability of the lungs under pressure. Higher compliance means greater stretchability

Question 33

turbulent flow

Answer 33

spiral or cicular flow, the change in pressure is proportional to flow cubed.

Question 34

laminar flow

Answer 34

straight, low density gas flow, the change in pressure is proportional to flow

Question 35

Pneumotachograph

Answer 35

air flows through many very thin tubes, pressure measured in two places. A drop in pressure = flow

Question 36

nicotinic receptor

Answer 36

a type of cholinergic receptor found at neuromuscular junctions

Question 37

muscarinic receptor

Answer 37

a type of cholinergi receptor found in the parasympathetic nervous system, M3 is the most important- found in airway smooth muscle cells causes bronchoconstriction

Question 38

affinity

Answer 38

how well the ligand binds to the receptor

Question 39

efficacy

Answer 39

how well the ligand activates the receptor- extend of conformational change etc.

Question 40

epithelium lining the bronchus

Answer 40

ciliated columnar epithelium

Question 41

bronchiole epithelium

Answer 41

cuboidal ciliated

Question 42

alveoli epithelium

Answer 42

2 types of cell- type one (larger) and two pneumocytes (secrete surfactant)

Question 43

granuloma

Answer 43

an aggregation of epithelial tissue macrophages

Question 44

henrys law

Answer 44

the amount of gas dissolved is proportional to the partial pressur of a gas with which the liquid is in equilibrium at a given temperature. ie the more inert gases dissolve better at higher pressures

Question 45

what is the strongest drive to breathing in healthy individuals

Answer 45

pCO2 as H+ ion channels are much more common in the body and much less complex.

Question 46

Autacoids

Answer 46

Generic term for local hormones eg histamine