Physiology

Question 1

What is Partial pressure of O2 in Arterial Blood

Answer 1

13.3 kPa

Question 2

What is Partial Pressure of O2 in venous blood

Answer 2

5.3kPa

Question 3

What region in the body has the lowest pO2?

Answer 3

Mitochondria

Question 4

What type of Haemoglobin is very common in foetus’ but not adults?

Answer 4

Y haemoglobin

Question 5

What is Thalassaemia?

Answer 5

An inherited defect in globin chain synthesis

Question 6

What causes Sickle Cell disease

Answer 6

A mutation in B Globin causing Glutamine to become Valine

Question 7

What does a rightwards Oxyhameoglobin curve shift cause?

Answer 7

Reduced affinity for O2

Question 8

What does a leftwards Oxyhameoglobin curve shift cause?

Answer 8

Increase O2 affinity

Question 9

How is methameoglobin produced?

Answer 9

O2 oxidising the Haem from Fe2+ to Fe3+

Question 10

What is the problem with too much methaemoglobin?

Answer 10

It cannot bind to O2 so causes hypoxia

Question 11

At what percentage of methameoglobin is methamoglobinaemia diagnosed?

Answer 11

Over 5%

Question 12

What percent of alveolar gas is turned over in the lungs each breath?

Answer 12

About 15%

Question 13

What is Vital Capacity

Answer 13

Total volume of gas inhaled or exhaled im 1 breath

Question 14

What is Residual Volume?

Answer 14

Total volume of gas left in lungs after maximal expiration

Question 15

What part of the lungs have better Perfusion?

Answer 15

The base of the lungs

Question 16

Why is there greater ventilation at the base of the lung?

Answer 16

Fluid in the pleural cavity increases intrapleural pressure at the base compacting alveoli, this means a greater volume increase from inspiration

Question 17

What is a VQ mismatch?

Answer 17

When venous blood passes through poorly ventilated areas it will not fully oxygenate

Question 18

What Ph should blood be at?

Answer 18

7.35-7.45

Question 19

What is it called if Ph<7.35

Answer 19

Acidemia

Question 20

What is it called if Ph>7.45

Answer 20

Alkalaemia

Question 21

What happens if Ph is too high in the blood?

Answer 21

The increased H+ will denature enzymes

Question 22

What will adding H+ to a buffer do to an equilibrium?

Answer 22

Shift equilibrium to the left

Question 23

What is a carbamino compund?

Answer 23

When CO2 combines wih amino acids/proteins

Question 24

What is Respiratory Acidosis

Answer 24

Increased PaCO2

Question 25

What is Respiratory Alkalosis

Answer 25

Decreased PaCO2

Question 26

What is Metabolic Acidosis

Answer 26

Non-respiratory increase in Acid

Question 27

What is Metabolic Alkalosis

Answer 27

Non-respiratory decrease in Acid

Question 28

What is minute ventilation?

Answer 28

Tidal volume x Respiratory rate

Question 29

What is a dead space in ventilation?

Answer 29

Areas that are not involved in gas exchange

Question 30

How do you calculate Alveolar Ventilation?

Answer 30

(Tidal Volume - Dead Space) x Resp. Rate

Question 31

What are the peripheral chemoreceptors in ventilation called?

Answer 31

Carotid bodies

Question 32

How is ventilation controlled centrally

Answer 32

Chemoreceptors on ventral surfaces of medulla

Question 33

What range should PaCO2 be?

Answer 33

4.5kPa - 6.0kPa

Question 34

What is a Pulmonary Stretch receptor

Answer 34

Smooth muscle in airway which is stimulated by lung inflation

Question 35

What nerve stimulates the diaphragm?

Answer 35

Phrenic nerve

Question 36

What is alveolar pressure?

Answer 36

The sum of pressure acting on the outside of the alveolus and pressure generated by elastic recoil

Question 37

How is pleural pressure determined?

Answer 37

Passing a balloon into the oesophagus

Question 38

Why does resistance increase with effort?

Answer 38

Small airways are compressed by external pressure

Question 39

What is the purpose of surfactant

Answer 39

Lowers surface tension to make expansion easier

Question 40

What is a restrictive lung disease?

Answer 40

Decrease of lung compliance restricitng inflation, it increases expiratory drive

Question 41

What is an obstructive lung disease

Answer 41

Impaires airflow possibly due to airway narrowing

Question 42

What is emphysema?

Answer 42

Enlargement of air spaces distal to terminal bronchioles resulting in loss of alveolar walls and elastic recoil

Question 43

What is bronchitis?

Answer 43

Chronic overproduction of mucus in the bronchial tree

Question 44

The heart can depolarise itself, what is the term used to describe this?

Answer 44

Automaticity

Question 45

What do nodal cells do?

Answer 45

Set rhythm/ pace of the heart

Question 46

What cells are used to produce force within the heart?

Answer 46

Contractile cells

Question 47

Where is the SA node found?

Answer 47

Superior part of the Right Atrium beneath the SVC

Question 48

What beat does the SA node usually set? What is it known as?

Answer 48

60-80 bpm, called sinus rhythm

Question 49

How does the SA node give Innervation to the AV node?

Answer 49

Intermodal pathways

Question 50

Why is there a delay in the AV node firing to the bundle of HIS

Answer 50

To give the atria a chance to contract before the ventricles do

Question 51

What does the Bundle of HIS split into?

Answer 51

Right and Left bundle branches

Question 52

What do the Right and Left bundle branches break into?

Answer 52

Purkinje fibres

Question 53

Give an example of a vasoconstrictor released by the endothelium

Answer 53

Endothelin

Question 54

Give 2 examples of a vasodilator produce by endothelium

Answer 54

Nitric oxide and Prostacyclin

Question 55

What happens when there is low O2 detected in vessels near the lung and why?

Answer 55

Vasoconstriction to improve VQ matching

Question 56

What is autoregulation

Answer 56

The ability of an organ to maintain constant blood flow despite alterations in perfusion pressure