Bio 2

Question 1

Oxygen haemoglobin curve

Answer 1

O2 carried on haem

Binds to haemoglobin at the lungs

Detaches from haemoglobin at the tissues

Question 2

CO2 + H2O ~~~~~ H2 CO3 ( carbonic acid) ——H+ + HCO3-( bicarbonate ion)

Answer 2

H+ is buffered by haemoglobin in erythrocytes

Question 3

Ventilation perfusion matching V/Q

V = air moving in and out of the lungs 
Q = blood in pulmonary capillaries

Answer 3

Normal oxygenation needs a matching of ventilation and perfusion (V/Q)

Question 4

Partial pressure of oxygen (PaO2)

Air is breathed in at 160mmHg

Air in alveoli is dropped to 100mmHg
Inspired air mixes with residual air and is also humidified

PaO2 in arterial blood is approx 100mmHg

Answer 4

The intrapleural pressure gradient is largest in the upper lung region

Question 5

Maintaining homeostasis:
Low PaO2 causes CONSTRICTIONS of pulmonary arterioles

Lack of homeostasis:
Obstruction of airways in COPD leads to hypoxiaemia and hypercapnia

Answer 5

Lack of homeostasis with reduced ventilation

Question 6

V/Q mismatch - reduced perfusion

Maintaining homeostasis

Answer 6

High PaO2 causes dilation of pulmonary arterioles

Low PaCO2 causes constriction of bronchioles

Question 7

Lack of homeostasis with reduced perfusion

Answer 7

Lack of homeostasis occurs with pulmonary embolisms

Leading to hypoxiaemia and hypercapnia

Question 8

Control of respiratory function:

SNS

Answer 8

Releases adrenaline and noradrenaline

Binds to B2 adrenergic receptors on bronchi which causes bronchodilation
Increased depth and rate of breathing
A sympathetic agonist enhances these effects

Question 9

Sympathetic agonist

Answer 9

Group of medication that enhances the effects of B2 adrenergic receptors located on the bronchi …
Bronchodilation

Question 10

Parasympathetic nervous system PNS

Rest and digest

Answer 10

Releases acetylcholine (ACh) neurotransmitter
Binds to cholinergic receptors on bronchi
bronchoconstriction
Decreases rate and depth of breathing

Parasympathetic antagonist/blocker opposes these effects

Question 11

B2 agonist

Salbutamol

Answer 11

Increases effects of SNS
Relaxes smooth muscle of bronchi
Bronchodilation

Question 12

Anti cholinergic

Iptratropium

Answer 12

Blocks cholinergic receptors
Relaxes smooth muscle of bronchi
Decrease the effects of PNS
Bronchodilation

Question 13

Corticosteroids

Fluticasone

Answer 13

Anti inflammatory
Reduces swelling
Prevents bronchospasm

Question 14

Respiratory control

Answer 14

Brain stem receives sensory input from chemoreceptors

Question 15

Central chemo receptors in the

Answer 15

Medulla

Question 16

Peripheral chemoreceptors in the

Answer 16

Carotid arteries and aortic arch

Question 17

Chemical control of O2

Answer 17

Decrease in O2 ( hypoxaemia )is detected by peripheral chemoreceptors

Question 18

Chemical control of CO2

Most important chemical

Answer 18

Increased co2 = hypercapnia

Detected by central chemoreceptors
Co2 from blood enters CSF ( cerebrospinal fluid) & forms H+

Also detects ketoacidosis in diabetes

Question 19

Increased H+ detected by central chemoreceptors causes

Answer 19

Increased rate and depth of breathing to get rid of co2 and increase blood pH

Question 20

Causes of acidosis

Answer 20

Hypoventilation

Diabetic ketoacidosis

Question 21

Respiratory acidosis

Less than 7.35 pH
PCO2 greater than 45mmHg

Answer 21

Occurs with hypercapnia and hypoventilation

Any impairment of lung function

Question 22

Respiratory alkalosis

PCO2 less than 35mmHg
pH greater than 7.45

Answer 22

Due to hypocapnia and hyperventilation

Question 23

Pulmonary function test

FEV = forced exploratory volume
FVC = forced vital capacity

Answer 23

FEV1/FVC x 100

Question 24

Syncope

Answer 24

Loss of consciousness caused by fall in blood pressure

Question 25

Haemoptysis

Answer 25

Coughing up of blood

Question 26

Pulmonary embolism clinical features

Answer 26

``` Breathlessness or chest pain Tachycardia Tachypnoea Dyspnoea Syncope Haemoptysis ```

Question 27

Restrictive lung disease RLD

Answer 27

Impaired lung expansion | Normal FEV1

Question 28

RDS | Respiratory distress syndrome of the newborn

Answer 28

Immature lungs - premis Alveoli collapse due to insufficient SURFACTANT Chest wall is weak Alveoli and blood supply underdeveloped

Question 29

RDS risk factors

Answer 29

Premature birth Caesarean Maternal diabetes Asphyxia at birth

Question 30

RDS treatment

Answer 30

Prevent premature birth Maternal glucocorticoids to speed up lung development Surfactant therapy CPAP (continuous positive air pressure )

Question 31

ARDS - excessive inflammation damages the alveoli Acute lung inflammation Life threatening

Answer 31

Sepsis - blood infection Trauma Pneumonia Smoke inhalation

Question 32

ARDS clinical features Develops within 24hrs following injury

Answer 32

Dyspnoea Hyperventilation Severe hypoxaemia

Question 33

ARDS treatment

Answer 33

``` Oxygenation of tissues Prone position Minimise lung injury Avoid complication Pts can recover ```

Question 34

Mixed venous blood

Answer 34

PO2 = 40 mm Hg | Haemoglobin is 75% saturated