Applied Basic Science

Question 1

what muscle is involved in quiet breathing?

Answer 1

diaphragm

Question 2

how does intrapleural pressure change on inspiration & expiration?

Answer 2

• Fall during inspriation
• Rises during expiration

Question 3

what is tidal volume?

Answer 3

air moving in & out of the lung

Question 4

what effect does posture on breathing?

Answer 4

diaphragms movement is facilitated by a sitting position as opposed to lying down

Question 5

what parts of the airway make up the conducting zone?

Answer 5

• trachea
• bronchi
• bronchiole

Question 6

what is the conducting zone of the airway?

Answer 6

anatomical dead space, region of NO gas exchange

Question 7

what is the respiratory zone?

Answer 7

region of the airway where gas exchange occurs

Question 8

what parts of the airway make up the respiratory zone?

Answer 8

• respiratory bronchiole
• alveolar duct
• alveolar sac

Question 9

what is the volume of the conducting zone (alongside the oral & nasal cavity)?

Answer 9

150ml of dead space

Question 10

what is the average tidal volume of the airway?

Answer 10

450ml

Question 11

how do gasses move across the alveolar wall?

Answer 11

diffusion (that is determined by partial pressure gradients)

Question 12

in an upright person, where are ventilation & perfusion greater?

Answer 12

base of the lung

Question 13

what gas does not bind to haemoglobin?

Answer 13

nitrous oxide (it is carried in simple solution in blood)

Question 14

what type of protein is haemoglobin?

Answer 14

Globular protein

Question 15

What is the structure of haemoglobin?

Answer 15

Globular protein made up of 2 alpha & 2 beta chains
- 4 haeme groups

Question 16

How does oxygen bind to haemoglobin?

Answer 16

Oxygen binds to the iron atom found within the haemoglobin structure

Question 17

How is oxygen transported?

Answer 17

• attached to haemoglobin (97%)
• dissolved in plasma (3%)

Question 18

what is it called when the Hb-O2 dissociation curve shifts to the right or left?

Answer 18

Bohr shifts

Question 19

What conditions cause the Hb-O2 dissociation curve to shift to the left? what does this mean?

Answer 19

Shift to left = increased affinity for oxygen

Caused by = decreased temperature & reduced acidity

Question 20

What conditions cause the Hb-O2 dissociation curve to shift to the right? what does this mean?

Answer 20

Shift to right = decreased affinity for oxygen

Caused by = increased temperature & increased acidity

Question 21

How is carbon dioxide transported?

Answer 21

Via the:
- erythrocytes
- plasma

Question 22

what is hypoxia?

Answer 22

reduction of oxygen delivery to tissues

Question 23

What are the different types of hypoxia?

Answer 23

• hypoxic hypoxia
• anaemic hypoxia
• stagnant (ischaemic) hypoxia
• cytotoxic hypoxia

Question 24

What are the causes of hypoxic hypoxia?

Answer 24

• reduced oxygen reaching alveoli
• reduced oxygen diffusion into blood

Question 25

What is the cause of anaemic hypoxia?

Answer 25

reduced oxygen transport in blood due to low haemoglobin

Question 26

what is the cause of stagnant hypoxia?

Answer 26

reduced oxygen transport in blood due to low blood flow

Question 27

What is the cause of cytotoxic hypoxia?

Answer 27

reduced oxygen utilisation of cells

Question 28

what is cyanosis? what causes it?

Answer 28

- Blue colouration of skin & mucous membranes - Due to >5mg de-oxygenated haemoglobin/dl of blood

Question 29

what is central cyanosis? what is it usually caused by?

Answer 29

- Affects whole body; it is evident in oral tissues - Generally due to decreased oxygen delivery to blood (hypoxic hypoxia)

Question 30

What is peripheral cyanosis? What is the cause?

Answer 30

- Due to decreased oxygen delivery to a localised & peripheral part of the body - Stagnant hypoxia can cause this

Question 31

what are the four main valves of the heart?

Answer 31

- tricuspid - pulmonary - mitral - aortic

Question 32

how does arterial blood supply the heart?

Answer 32

Via the right & left coronary arteries (and their branches) which supply the myocardium

Question 33

What allows venous drainage of the heart?

Answer 33

Via coronary veins into the right atrium

Question 34

what nerve innervates the heart via the parasympathetic branch?

Answer 34

vagus nerve

Question 35

What are the two most commonly used cannulation sites?

Answer 35

- cubital fossa - dorsum of hand

Question 36

What veins run via the dorsum of the hand?

Answer 36

- Basilic vein - Cephalic vein

Question 37

What are the positives of cannulating a patient via the dorsum of the hand?

Answer 37

- easy access - no nearby arteries - no nearby nerves - no joints

Question 38

What are the negatives of cannulating a patient via the dorsum of the hand?

Answer 38

- small veins - susceptible to cold/anxiety - mobile veins - more painful

Question 39

What veins run via the cubital fossa in the forearm?

Answer 39

- cephalic vein - median cephalic vein - basilic vein

Question 40

What arteries run via the cubital fossa in the forearm?

Answer 40

- brachial artery - medial basilic vein

Question 41

what are the pros of cannulating a patient via the cubital fossa?

Answer 41

- big, well tethered veins - less painful - less venoconstriction

Question 42

what are the cons of cannulating a patient via the cubital fossa?

Answer 42

- difficult access - potential nerve damage - potential intra arterial injection - joint immobilisation