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Flashcards in Bio 2 Deck (34)
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1
Q

Oxygen haemoglobin curve

A

O2 carried on haem

Binds to haemoglobin at the lungs

Detaches from haemoglobin at the tissues

2
Q

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

A

H+ is buffered by haemoglobin in erythrocytes

3
Q

Ventilation perfusion matching V/Q

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

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

4
Q

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

A

The intrapleural pressure gradient is largest in the upper lung region

5
Q

Maintaining homeostasis:
Low PaO2 causes CONSTRICTIONS of pulmonary arterioles

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

A

Lack of homeostasis with reduced ventilation

6
Q

V/Q mismatch - reduced perfusion

Maintaining homeostasis

A

High PaO2 causes dilation of pulmonary arterioles

Low PaCO2 causes constriction of bronchioles

7
Q

Lack of homeostasis with reduced perfusion

A

Lack of homeostasis occurs with pulmonary embolisms

Leading to hypoxiaemia and hypercapnia

8
Q

Control of respiratory function:

SNS

A

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

9
Q

Sympathetic agonist

A

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

10
Q

Parasympathetic nervous system PNS

Rest and digest

A

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

Parasympathetic antagonist/blocker opposes these effects

11
Q

B2 agonist

Salbutamol

A

Increases effects of SNS
Relaxes smooth muscle of bronchi
Bronchodilation

12
Q

Anti cholinergic

Iptratropium

A

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

13
Q

Corticosteroids

Fluticasone

A

Anti inflammatory
Reduces swelling
Prevents bronchospasm

14
Q

Respiratory control

A

Brain stem receives sensory input from chemoreceptors

15
Q

Central chemo receptors in the

A

Medulla

16
Q

Peripheral chemoreceptors in the

A

Carotid arteries and aortic arch

17
Q

Chemical control of O2

A

Decrease in O2 ( hypoxaemia )is detected by peripheral chemoreceptors

18
Q

Chemical control of CO2

Most important chemical

A

Increased co2 = hypercapnia

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

Also detects ketoacidosis in diabetes

19
Q

Increased H+ detected by central chemoreceptors causes

A

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

20
Q

Causes of acidosis

A

Hypoventilation

Diabetic ketoacidosis

21
Q

Respiratory acidosis

Less than 7.35 pH
PCO2 greater than 45mmHg

A

Occurs with hypercapnia and hypoventilation

Any impairment of lung function

22
Q

Respiratory alkalosis

PCO2 less than 35mmHg
pH greater than 7.45

A

Due to hypocapnia and hyperventilation

23
Q

Pulmonary function test

FEV = forced exploratory volume
FVC = forced vital capacity
A

FEV1/FVC x 100

24
Q

Syncope

A

Loss of consciousness caused by fall in blood pressure

25
Q

Haemoptysis

A

Coughing up of blood

26
Q

Pulmonary embolism clinical features

A
Breathlessness or chest pain
Tachycardia
Tachypnoea
Dyspnoea
Syncope
Haemoptysis
27
Q

Restrictive lung disease RLD

A

Impaired lung expansion

Normal FEV1

28
Q

RDS

Respiratory distress syndrome of the newborn

A

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

29
Q

RDS risk factors

A

Premature birth
Caesarean
Maternal diabetes
Asphyxia at birth

30
Q

RDS treatment

A

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

31
Q

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

A

Sepsis - blood infection
Trauma
Pneumonia
Smoke inhalation

32
Q

ARDS clinical features

Develops within 24hrs following injury

A

Dyspnoea
Hyperventilation
Severe hypoxaemia

33
Q

ARDS treatment

A
Oxygenation of tissues 
Prone position
Minimise lung injury
Avoid complication
Pts can recover
34
Q

Mixed venous blood

A

PO2 = 40 mm Hg

Haemoglobin is 75% saturated