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Flashcards in Physiology and Pharmacology Deck (66)
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1
Q

Difference between internal and External respiration?

A

Internal is within the cell e.g. glycolysis, Krebs, whereas External is ventilation and exchange of gases around the body.

2
Q

What are the 4 stages of exchange of gases around the circulatory system?

A

External Convection, Pulmonary Diffusion, Internal Convection, Tissue diffusion

3
Q

What are the two lung groups? What are they and the components?

A

Conducting Zone: No gas exchange just getting air to the respiratory zone. Trachea, Bronchi, broncholes (generation 11-16)
Respiratory Zone: Alveoli, Alveoli ducts (20-22), Alveoli sacs (gen 23)

4
Q

What is the function of the Conducting zone?

A
  • Filters air so doent clog airways
  • Warms the air to body temperature- solubility depends on temp
  • Humidity-maintains alveoli being moist
5
Q

Bronchii structure?

A
  • Reinforced with catilage to stop airways collapsing
  • Underlayer of smooth muscle allowing diameter to be altered.
  • Elastic Tissue- helps recoil and prevents over expansion of airways.
6
Q

Features of Respiratory Epithelium?

A
  • Ciliated epithelia
  • Goblet cells- bacteria in mucus trapped
  • sensory nerve endings- detect noxious smoke etc
7
Q

Bronchioles structure? Diameter?

A
  • Lack of cartilage
  • Less than 1mm diameter
  • Lined by respiratory epithelium
  • Smooth muscle layer- more than bronchi which controls airway diameter.
8
Q

Two types of cells in epithelia in the air blood barrier?

A

Epithelial Pneumocytes:

  • Type 1: Very thin for gas exchange
  • Type 2: Produce surfactant
9
Q

What physiological changes happen for quiet inspiration to happen? (2)

A
  • Active, Involves the primary muscles of inspiration
  • Diaphragm- moves down as contracts, vol increases
  • Intercostal muscles- move chest up and out vol up
10
Q

What physiological changes happen for forced inspiration to happen? (4)

A

Active. Involves the accessory muscles of inspiration:

  • Scalenes- attatch to ribs to bring up
  • Sternocleidomastoids- bring sternum up
  • Neck and back muscles- lifts and raises
  • Upper respiratory tract muscles- changes in tension reduces resistance to air flow.
11
Q

What physiological changes happen for quiet expiration to happen? (3)

A

Passive. Elastic recoil used. No primary muscles of expiration Diaphragm relaxes, external intercostal muscles relax, and lungs recoil.

12
Q

What physiological changes happen for forced expiration to happen? (2)

A

Active. Accessory Muscles:

  • Abdominal muscles- contract, reduces size of abdomen
  • Neck and back muscles contract.
13
Q

What are the Pleural membranes? Used for?

A

Pleural cavity between which is filled with secretions, preventing the lungs sticking to the chest wall, so can slide over each other
- Subatmospheric pressure

14
Q

What is Pneumothorax?

A

Collpased lung. Breech of chest wall, air into interpleural space, lose sub-atmospheric pressure.

15
Q

What does low compliance mean?

A

More work required to inspire as hard to expand. e.g. Pulmonary Fibrosis

16
Q

What does High compliance mean?

A

More difficulty expiring due to elastic recoil, e.g. emphysema

17
Q

Equation for compliance?

A

change in volume/ change in pressure

18
Q

What are the two major components of elastic recoil?

A
  1. Surface tension: of the alveoli at the air fluid interface
  2. Anatomical component: elastic nature of the cells and ECM
19
Q

What is Laplace equation?

A

Pressure= 2Tension/Radius

20
Q

What causes serface tension in the alveoli?

A

H20 molecules make 4 bonds- at the surface they have no force attracted to upwards so attracted downwards creating a tension

21
Q

According to Laplace’s equation, the pressure in the smaller/larger alveoli sacs leading to..
Overcome by…

A

Smaller
collapses
surfactant

22
Q

Can measure respiratory volumes from a …. but not ….

A

spirometer

residual volume

23
Q

What is Anatomical dead space?

A

Volume of the conducting airways at rest (30%)

24
Q

What is physiological dead space?

A

Volume of lungs not participating in gas exchange. Conducting zone + any non functioning areas in respiratory zone.

25
Q

What is the IRV?

A

Inspiratory reserve volume: additional air that can be forcefully inhaled after tidal volume. (3.1l)

26
Q

What is TV?

A

Tidal volume: The amount of air displaced in a quite inspiration and expiration in one breath. (0.5l)

27
Q

What is ERV?

A

Expiratory Reserve volume: additional air that could be forcefully exhaled above tidal volume. (1.3l)

28
Q

What is RV?

A

Residual volume: The volume of air in the lungs after a forced expiration that cannot be expired. (1.7l)

29
Q

What is TLC?

A

Total Lung capacity: VC + RV total volume the lung can hold.

30
Q

What is FRC?

A

Functional Residual Capacity: Volume of lungs left after a quiet expiration.

31
Q

What is IC?

A

Inspiratory Capacity: Total volume can inspire forcefully after a normal expiration. (2.6l)

32
Q

What is VC?

A

Vital capacity: The maximum volume of air that one can exhale after a maximum inspiration. (4l)

33
Q

What is FEV1? If under 80% suggests..

A

Forced Expiratory Volume in 1 second. if under 80% of FVC the suggests an obstructive lung disease e.g. pulmonary fibrosis.

34
Q

What is FVC? If lower than normal suggests..

A

Forced vital capacity: Total volume of air that can be exhaled forcefully. If low suggests a constrictive lung disease e.g. asthma, emphysema.

35
Q

During exercise what happens to IRV and ERV? Why?

A

They decrease as the tidal volume increases to get more oxgen round the body to the respiring muscles.

36
Q

How can the residual volume be measured?

A

With a helium air chamber.

37
Q

Volume of air to the lungs equation:

A

V= Change in pressure/ resistance

change in pressure = Pressure in alveoli- Pressure in atmosphere

38
Q

The resistance is worked out by what law? Which is..

A

Poiseulle’s law
R= 8/pi x nl/ r^4
or resitance is inversely proportional to the forth power of radius. And proportional to gas viscocity.

39
Q

Phaynx and Larynx total ….of total resistance.
AIrways over 2mm diameter….(why?)
Airways under 2mm diameter… (why?)

A

40%
20%- should be low but counted in series so R1+R2 etc
20% - should be high due to low radius but these are counted in parallel as not one continuous cycle so 1/R + 1/R2 etc

40
Q

Factors that affect airway resistance? (4)

A

Airway diameter
Increased mucus secretion- blocks
Oedema- swells diameter down
Airway collapse- if pressure less than outside and no cartalidge can collapse.

41
Q

How does the sympathetic/ Para work to alter the Bronchii diameter?

A

Parasympathetic: ACh released from the vagus nerve bind to muscarnic receptors leading to constriction of the smooth muscle. Resistance increases.
Sympathetic: Release of Noradrenaline leads to dilation so resistance decreases- weak agonist e.g Salbutamol inhaler.

42
Q

Affect of Histamine and Adrenaline on the Bronchial smooth muscle?

A

Adrenaline: agonist leads to dilation- reistance down.
Histamine: inflammatory response- constriction.

43
Q

Which are higher at the base of lungs/ Apex… pressure? Ventilation? Perfusion?

A

Pressure- highest at the apex
Ventilation- highest at the base (alveoli can expand more)
perfusion- highest at the base

44
Q

Ventilation/ perfusion ratio in apex vs base? shows efficiency.

A

Apex: 3.3 high
Base: 0.6 low
Ventilation= volume of air that reaches the alveoli
Perfusion= volume of blood that reaches the alveoli
High vol of blood (and air) to base therefore low ratio at base.

45
Q

The amount of gas dissolved in a solution can be measured using Henry’s law, which is?

A

Gas dissolved= Solubility coefficient (mM/mm Hg) x Partial pressure of the gas

46
Q

Haemoglobin has what structure and what Molecular weight?

A

Tetromeric structure of 4 subunits (each contains one haem and 4 globin chains- 2x Alpha and B in adults)
68KD

47
Q

Haem structure in haemoglobin? What state does it have to be in?

A

Contains an iron atom and for oxgen to bind needs to be in the FE^2+ state. Methaemoglobin reductase converts any FE^3+ to 2.

48
Q

Haemoglobin exists in which two states?

A

Tense: low O2 binding affinity
Relaxed: high O2 finding affinity

49
Q

Explain the haemoglobin dissosiation curve?

A

1st- hard to bind
2nd to 4th- easier due to induced conformational change.
after 4th- saturated

50
Q

What factors cause a right shift in dissociation curve of haemoglobin? (4)

A

Right shit= lower affinity

  • Temp increase
  • PH decrease
  • Increased production of CO2
  • Increased Production of 2,3 DPG (diphosphoglycerate, causes conformational change loses bound O2)
51
Q

Difference in fetal Haemoglobin?

A

B globin chains replaced by Y. Left shift on dissociation curve.

52
Q

Total percentage of CO2 carried dissolved in capilaries- in what two forms?

A

11%

  • 6% dissolved
  • 5% as bicarbonate (HCO3- + H+ )
53
Q

What percentage of CO2 is carried in the blood in red blood cells? What three forms?

A

89%

  • 4% dissolved.
  • 64% bicarbonate (HC03-)
  • 21% carbamino haemoglobin
54
Q

How is CO2 in RBCs converted to Bicarbonate?

A

H20 enters the cell and the OH- joins the CO2 to make HCO3- +H+ under carbonic anhydrase (64% Co2 carriage)

55
Q

Obstructive Lung diseases vs Restrictive?

A

Obstructive: reduction in flow through airways FEV1 decrease and concave flow vol loop.
Constrictive: Reduction in lung expansion. FVC decreased

56
Q

obstructive lung disease causes? (3)

A
  • Excess secretions
  • Bronchioconstriction e.g. Asthma
  • Inflammation
57
Q

Examples of obstructive lung diseases?

A
  • Asthma
  • COPD
  • Emphysema
  • Chronic Bronchitis
58
Q

Asthma is either triggered by one of two types of causes?

A
  • Atopic (extrinsic): allergies

- Non- Atopic (intrinsic): Respiratory infections, cold air, exercise, stress, irritants, drugs.

59
Q

What is the response in asthma?

A

Inflammatory cells move into the airways and release inflammatory mediators e.g. histamine causing bronchioconstriction.

60
Q

Whats the treatment of asthma?

A
  • Short acting Salbutamol blue inhalers B2 adrenoreceptor agonists causes dilation of airways.
  • Long term-inhale steroids such as Glucocorticoids long acting B adrenoreceptor agonists.
61
Q

Reasons for Restrictive lung diseases?

A
  • Decreased chest expansion due to chest wall abnormalities, or muscle contraction difficulties
  • Loss of compliance (fibrosis) due to normal aging, or increase in collagen.
62
Q

What is Asbestosis?

A

Slow build up of fibrous tissue leading to a loss of complance in the lungs. e.g. from aspesdos particles.

63
Q

The basic rhymthmical process is generated by sensors in the..

A

Medulla oblongata.

64
Q

What controls the inspiration by sending signals to the inspiratory muscles?

A

Dorsal Respiratory Group.

65
Q

What controls forced inspiration and expiration?

A

Ventral Respiratory Group

66
Q

Renin is released from?

A

Juxtaglomerular apparatus In the kidney