Respiration Flashcards

Question

What is lung compliance

Answer 1

*Ability of lungs to stretch *Elasticity *Surface tension *Change in lung volume produced by change in transpulmonary pressure *Greater compliance, easier to expand lungs, inverse of stiffness *Decreased compliance, shallow, rapid breathing Compliance (change in) Lung volume / (change in) (Palv -Pip) same as (change in) V / (change in) Ptp

Answer 2

Unknown cause

Answer 3

Destruction of structures supporting the alveoli, often due to smoking, causing loss of elasticity. It increases, as the pressures needed for the same volume are less due to loss of elastic tissue. like a paper bag can't recoil.

Answer 4

In lung fibrosis (often occurring in interstitial lung disease/occupational lung disease) Very stiff and hard alveoli. It decreases, as the pressures needed for the same volume are greater. Patient needs lots of energy to take a breath

Answer 5

The lungs are like a rubber balloon The chest is like a spring The ribcage springs out but the lungs collapse The chest wall is energetically more happy at a higher volume hence they expand out.

Answer 6

Functional residual capacity pressure between lung and chest wall is balanced (equal and opposite). It is the volume in lungs when you breath out before breathing in. you can artificially change FRC for short period of time but it messes up the balance. Makes it energy inefficient

Answer 7

Surfactant = lipids and proteins secreted by type II alveolar cells Lowers alveolar surface tension Increases compliance Reduces recoil Prevents alveoli collapsing infant/other Respiratory distress syndrome (near drowning can cause this-it can wash out surfactant) all detergents lower surface tension

Answer 8

When water forms a surface layer with air, the surface H2O molecules have a strong attraction e.g. needle/rain drop, though not with detergent. In alveoli, H2O attracts other H2O molecules & they force out air and attempt to collapse the alveolus.

Answer 9

Have to use La Place’s Law to help us. This tells us the pressure needed to keep a sphere open is: P = pressure P = 2 x T / radius T = surface tension r = sphere radius P is equal and opposite to the collapsing pressure.

Answer 10

This would be a disaster for the lungs at low lung volumes (especially for premature neonates), as all the alveoli would collapse. To reopen them would take a great amount of pressure (as r would be very small). But this does not occur in reality, otherwise every breath would take a tremendous effort. surfactant works better in smaller alveoli The reason this doesn’t happen is that: Alveoli share common septal walls Surfactant gets more concentrated in smaller alveoli, therefore PA = 2 x 15 / 1= 30 (same as B)

Answer 11

(Minute volume, VE) = tidal volume x respiratory rate Minute volume approximately 6L, can increase to 200L Alveolar ventilation is more important than pulmonary ventilation (Tidal volume – dead space) x respiratory rate Quiet breathing = (500-150)x 12 = 4200 ml/min Deep slow breathing = (1200-150)x 5 = 5250 Shallow rapid breathing = (150-150)x 40 = 0 ventilation=tidal volume X frequency

Answer 12

Using lung volumes

Answer 13

Local controls match ventilation with perfusion Hypoxic pulmonary vasoconstriction – hypoxia causes vasoconstriction in the pulmonary vasculature, so blood can go to better ventilated alveoli (systemic opposite – vasodilation) less O2, less blood, vessels constricts

Answer 14

*Space/microgravity *G forces *Exercise *Body position *Disease

Answer 15

Gravity causes regional differences in ventilation and perfusion Hydrostatic pressure affects blood pressure and flow Blood flow decreases from base to apex Gravity alters intrapleural pressure – apex more expanded Ventilation higher at base than apex Ventilation perfusion ratio is higher in apex than base.

Answer 16

*O2 moves down a concentration gradients from: --> atmospheric-->alveoli-->plasma-->erythrocytes-->plasma-->interstitial fluid-->cells

Answer 17

sigmoidal curve

Answer 18

Low partial pressure of oxygen in muscle capillaries Haemoglobin READILY gives up O2 to Myoglobin Lungs - high partial pressure of oxygen, so Hb takes up O2 A steep Hill slope allows Hb to efficiently take up O2, then transfer it to Mb in the muscle Sigmoid plot suggests +ve co-operativity *more H+ more CO2 Higher temperature More BPG

Answer 19

biophospho glycerate Shift to right 1)increased hydrogen ions 2)increased CO2 3)Increased temperature 4)increased BPG This can be caused by exercise released by red blood cells exposed to hypoxia

Answer 20

Most of it combining with water to form bicarbonate and some binding on to hydroxy haemoglobin and some being dissolved. CO2 has 3 methods of being transported in the blood Deoxygenated Hb, increases capacity to carry CO2 Deoxygenated Hb binds H+ well. Haldane effect ‘For any given PCO2, the CO2 content of deoxygenated blood is greater than that of oxygenated blood’. Likewise, Oxygenated Hb, decreases capacity to carry CO2

Answer 21

CO has 210 x more affinity for HB than O2. It is a colourless, odourless gas. Carbon monoxide has a high affinity to haemoglobin. High levels of CO can be dangerous. incomplete combustion

Answer 22

Henderson-Hasselbach equation: CO2 + H2O <-->H2CO3-<-->HCO3- + H+ pH ∞ log [HCO3-]/[PCO2] If ratio remains constant, pH 7.4 Hypercapnia (high PCO2) due to hypoventilation will decrease HCO3-/PCO2 ratio, and pH, respiratory acidosis

Answer 23

Want to breathe enough to ensure Hb gets close to full saturation. Don’t want to breathe more than needed (keep WB minimum). Want to regulate CO2 quite carefully, as changes can vary pH. Double VE causes arterial pH to rise to 7.6, half it pH falls to 7.2. 7.4 is normal We sometimes have to ‘override’ automatic reflex control e.g. blowing, breath holding, swimming, speech etc.

Answer 24

When the effect of PO2 is investigated independently at constant PCO2, ventilation doesn't change until PO2 falls below 8kPa. The effects are increased if PCO2 is raised.

Answer 25

Found in brainstem (bilaterally in medulla oblongata & pons): Dorsal respiratory group (DRG) – inspiratory Ventral respiratory group (VRG) – inspiratory & expiratory Pneumotaxic centre - rate & pattern of breathing

Respiration Flashcards

(49 cards)