Physiology

Question 1

define internal respiration

Answer 1

mechanism that consumes oxygen and produces carbon dioxide

Question 2

define external respiration

Answer 2

exchange of oxygen and carbon dioxide between the environment and cells

Question 3

four steps in external respiration

Answer 3

1. ventilation
2. gas exchange between alveoli and pulmonary capillaries
3. exchange in the blood
4. systemic capillaries and cells

Question 4

two forces that hold the thoracic wall and lungs in close opposition

Answer 4

• intrapleural fluid cohesiveness

- negative intrapleural pressure

Question 5

describe intrapleural fluid cohesiveness

Answer 5

water molecules keep the pleural membranes together

Question 6

is inspiration an active process

Answer 6

yes

Question 7

how is the diaphragm flattened in inspiration

Answer 7

by the phrenic nerve (C3, 4 and 5)

Question 8

is expiration a passive process

Answer 8

yes

Question 9

two mechanisms of lung recoil in expiration

Answer 9

1. elastic connective tissue

2. alveolar surface tension

Question 10

describe alveolar surface tension

Answer 10

water and surfactant line the alveoli preventing collapse

Question 11

describe alveolar interdependence

Answer 11

alveoli work together to prevent collapse

Question 12

forces keeping the alveoli open

Answer 12

• pressure gradient
• surfactant
• alveolar interdependence

Question 13

forces promoting alveoli collapse

Answer 13

• elastic tissue

- alveolar surface tension

Question 14

accessory muscles of inspiration

Answer 14

sternocleidomastoid
scalenus
pectoral

Question 15

muscles of active expiration

Answer 15

abdominal muscles

internal intercostal muscles

Question 16

tidal volume

Answer 16

volume of air entering or leaving the lungs during a single breath

Question 17

residual volume

Answer 17

volume of air remaining after maximal expiration

Question 18

functional residual capacity

Answer 18

volume of air remaining after passive expiration

Question 19

vital capacity

Answer 19

maximum volume of air that can be moved out during a single breath following maximal inspiration

Question 20

spirometry result in obstructive lung disease

Answer 20

• reduced FEV1/FVC
• reduced FEV1
• FVC normal (not for COPD)

Question 21

spirometry in restrictive lung disease

Answer 21

• normal FEV1/FVC
• FEV1 reduced
• FVC reduced

Question 22

parasympathetic NS on the bronchi

Answer 22

bronchoconstriction

Question 23

sympathetic NS on the bronchi

Answer 23

bronchodilation

Question 24

define pulmonary compliance

Answer 24

measure of the effort that goes into stretching and distending the lungs

Question 25

what decreases pulmonary compliance?

Answer 25

``` fibrosis oedema collapse pneumonia absence of surfactant ```

Question 26

what increases pulmonary compliance

Answer 26

emphysema (loss of elastic recoil)

Question 27

define alveolar dead space

Answer 27

this is ventilated alveoli that are not adequately perfused with blood

Question 28

V/Q controls when CO2 increases

Answer 28

dilation of airways | constriction of blood vessels

Question 29

difference in pulmonary arterioles and systemic arterioles in decreased oxygen

Answer 29

pulmonary arterioles vasoconstrict

Question 30

four factors affecting the rate of gas exchange across the alveolar membrane

Answer 30

- partial pressure gradient - diffusion coefficient - surface area - thickness of the membrane

Question 31

dalton's law

Answer 31

pressure one gas in a mixture would exert if it occupied the whole volume

Question 32

Henry's law

Answer 32

partial pressure in gas phase is the same in liquid phase

Question 33

two forms of oxygen transportation around the body

Answer 33

- dissolved | - bound to Hb

Question 34

Bohr effect

Answer 34

shifts the oxygen dissociation curve to the right

Question 35

structure of foetal haemoglobin

Answer 35

2 alpha and 2 gamma subunits

Question 36

does foetal Hb have a higher affinity for oxygen than adult Hb?

Answer 36

yes

Question 37

three means of carbon dioxide transport in the blood

Answer 37

- solution - bicarbonate - carbamino compounds

Question 38

what are carbamino compounds?

Answer 38

combination of carbon dioxide and terminal amine groups in blood proteins (especially in Hb which makes carbamino-Hb)

Question 39

Haldane effect

Answer 39

removing oxygen from Hb increases ability to pick up CO2 and H+

Question 40

rhythm generator of respiration

Answer 40

medulla

Question 41

how is respiration initiated

Answer 41

pre-Botzinger complex in the top of the medulla

Question 42

what does the pre-Botzinger complex excite?

Answer 42

dorsal respiratory group neurones

Question 43

what do the dorsal respiratory group neurones do?

Answer 43

firing causes contraction of inspiratory muscles

Question 44

in active expiration what is the second group of neurones activated called?

Answer 44

ventral respiratory group neurones

Question 45

what does the ventral respiratory group neurones do?

Answer 45

excites accessory muscles of active expiration

Question 46

how can the rhythm of respiration be modified

Answer 46

pons

Question 47

role of the pneumotaxic centre

Answer 47

terminates inspiration

Question 48

role of the apneustic centre

Answer 48

prolongs inspiration

Question 49

four involuntary modifications of breathing

Answer 49

1. pulmonary stretch receptors (Hernia-Breuer reflex) 2. joint receptor 3. stimulation by temp, adrenaline or cerebral cortex 4. cough reflex

Question 50

describe the Hering-Breuer reflex

Answer 50

in the bronchi and bronchioles and guard against hyperinflation

Question 51

gas tensions are detectors

Answer 51

peripheral and central chemoreceptors

Question 52

where are peripheral chemoreceptors located?

Answer 52

carotid and aortic bodies

Question 53

where are central chemoreceptor located?

Answer 53

medulla (respond ot H+ in CSF- BBB)

Question 54

hypoxic drive of respiration

Answer 54

peripheral chemoreceptors are stimulated when pO2 falls below 8kPa

Question 55

chronic adaptions to high altitude hypoxia

Answer 55

- increased RBC - increased 2, 3 BPG (offloads O2 more easily) - increased capillaries - increased mitochondria

Question 56

H+ drive of respiration

Answer 56

peripheral chemoreceptors detect and adjust acidosis