Vocabulary

Question 1

external respiration

Answer 1

• The exchange of oxygen CO2 between blood, lung tissue and the external environment
• O2 in and Co2 out
  -airways allow air to reach gas exchange surfaces in the lungs
• incoming (inhaled) air is conditions - warmed and filtered by the respiratory tract
• the thin wall created by alveolar type 1 cells and pulmonary capillary endothelial cells allows for oxygen to diffuse into blood, and CO2 to diffuse into the alveolar cavity

Question 2

Internal respiration

Answer 2

the exchange of oxygen and CO2 between blood and other body tissues

• involves diffusion of gasses between blood and ISF across capillary walls
• O2 is able to diffuse down its concentration gradient skin to tissue, while the pressure gradient favours the uptake of CO2 in the blood

Question 3

Pulmonary Ventilation (breaking)

Answer 3

physically moves air into and out of the lungs

Question 4

Alveolus

Answer 4

is a capillary-wrapped gas exchange structure

Question 5

Respiratory Mucosa

Answer 5

• most of the respiratory tract is covered by the respiratory mucosa, which has protective specializations
• a mucous membrane (epithelium + basement membrane + connective tissue)

Question 6

Mucus

Answer 6

helps to condition (moisten) air, as well as filters air by trapping particles and pathogens

Question 7

Cilia

Answer 7

makes beating movements which constantly sweep secreted mucus toward the pharynx

Question 8

Pleura

Answer 8

• a double-layered membrane adheres each lung to the wall of the thoracic cage
• if skeletal muscles alter the shape of the thoracic cage, the lungs will also alter their shape

Question 9

Pressure Gradients

Answer 9

changes the size of the pleasurable cavity creates pressure gradients which drive airflow into and out of the lungs

Question 10

Inhalation

Answer 10

movements of inspiratory muscles expand the lungs, creating a neg pressure gradient

Question 11

Exhalation

Answer 11

when the muscles relax, the pressure gradient and airflow reverse

Question 12

Resting tidal volume

Answer 12

• very small differences (+/- 1mm Hg) in intrapulmonary pressure can create movement of air through the respiratory tract
• A single quiet breathing moves about 500mL of air into and then out of the lungs

Question 13

Accessory Muscle

Answer 13

increases the speed and magnitude of thoracic cage movements

Question 14

Phrenic motor neurons

Answer 14

(found in C3-C5) sent their axons in the phrenic nerve and innervate the myofibres of the diaphragm

Question 15

Spirometry

Answer 15

airflow in an out of the respiratory system can be measured using the spirometry

Measurements:
1. volume of air moving into or out of the respiratory system
2. How fast that air is moving

Question 16

Tidal Volume

Answer 16

• air moving in a single unit breathing
• is a small fraction of the total volume of air in the lungs
• A typical spirometry test involves periods f quiet breathing and a forceful inhalation and exhalation
• at rest, only a small volume of air moves into and out of the lung during a single breath

Vt = 500mL

Vt = tidal volume

Question 17

Inspiratory capacity and inspiratory reserve

Answer 17

• relate to the maximum volume of air that can be breathed into the lungs
• these measures are made when a subject is asked to breathe in as deeply as possible

IRV = IC - Vt

Vt= tidal volume
IRV = inspiratory reserve volume
IC = inspiratory capacity

Question 18

Expiratory reserve and vital capacity

Answer 18

• relate to the amount of air that can be breathed out in a maximal exhalation
• these measures are added when a subject is asked to breathe out as completely as possible

VC = ERV + Vt + IRV

ERV = Expiratory reserve volume
VC = Vital capacity

Question 19

Residual Volume

Answer 19

• which remains after maximal exhalation is a considerable fraction of title lung capacity

TLC = FRC + IC or TLC = RV + VC

TLC = Total lung capacity
FRC = Functional residual capacity
RV = Residual Volume (cannot be directly measured with spirometry)

• air left in the lungs even after maximal exhalation

Question 20

Respiratory reflexes can change breathing movements in terms of: (3 options)

Answer 20

• timing
• pattern
• force
  Note: all respiratory reflexes are long (neutral) reflexes

Question 21

Chemoreceptors

Answer 21

in the medulla are far more sensitive to changes in Pco2 than changes in Po2

Question 22

What is “sighing”
- function
- why is it helpful

Answer 22

• is a reflexive breathing pattern which creates a slow, deep breath
• this helps reinflate pulmonary lobules
• reinflating collapsed alveolar sacs required inspiration with greater force than that provided by resting tidal volume (Vt)
• this extra infraction force is provided by periodic reflexive sighs (single deep breaths)
• despite their surfactant layer, a small proportion of alveolar sacs in each lung collapse with every exhalation

Question 23

Protective reflexes
- coughing
- sneezing

Answer 23

• are powerful expiratory responses to irritants in the airway
• both patterns involve fuel exhalation of air against a partial constriction in the glottis
• this builds up high pressures so when the constriction is released, the airflow can (hopefully clear the airway)

Sneezing
- a purely involuntary reflex triggered by by the presence of irritants or particles in the nasal cavity or nasopharynx

Coughing
-reflexively triggered by the presence of irritants or particles in the lower respiratory tract (it can be performed voluntarily)
- involves closing the nasopharynx

Question 24

Total Volume

Answer 24

• is a small fraction of total lung capacity
• in quiet (resting) breathing, relatively few skeletal muscles are active (and only during the inspiratory phase)
• movements are relatively small with a tail volume of about 500mL

Question 25

Primary inspiratory muscle

Answer 25

use relatively little energy; only about 3-5% of resting energy demand

Question 26

Respiratory minute volume (Ve)

Answer 26

• measure the amount of air that is moved into the respiratory system per minutes
• Ve can be calculated directly from spirometry measurements

Question 27

Anatomical dead space

Answer 27

• the conduction passages add an anatomical dead space that leads to the mixing of used and fresh air
• a portion of inhaled and exhaled air always remains in the conducting regions of the respiratory tract
• this is called the ‘anatomical dead space’ (Vd) bc/ that air cannot contribute to alveolar ventilation

Question 28

Alveolar ventilation (Va)

Answer 28

• is a measure of the amount of air that redheads the alveoli per min
• the anatomical dead space reduces the effective size of the breath that can be used for external respiration
• ex: the amount that reaches a respiratory portion of the tract

VA = f * (VT - VD)

VA = Alveolar Ventilation
f = Breaths per min
VT = tidal volume
VD = Anatomic dead space

Question 29

Respiratory Minute Volume

Answer 29

VE = f * VT

Question 30

Alveolar Ventilation

Answer 30

VA = f * (VT- VD)

Question 31

Emphysema

Answer 31

• a lung disease caused by the destruction of respiratory tissue
• a result of prolonged inflammation and/ or exposure to toxic particulates in the air, which triggers the destruction of lung tissue, especially elastic fibres in the alveoli wall
• alveoli walls deteriorate = merging of adjacent alveoli, and losing alveolar surface area
• irreversible
• can elevate to lung cancer
• increases compliance for inflammation and reduces the elastic recoil of the lung
• associated with increased compliance; with less tissue in the alveolar wall, the lungs are easier to inflate

Question 32

Partial pressure (P)

Answer 32

is the pressure exerted by a single gas within a mixture of gases

Question 33

Dalton’s Law

Answer 33

in any gas or gas mixture, each individual molecule contributes the same amount to the overall pressure, no matter its chemical composition

Question 34

Henry’s Law

Answer 34

for a given temp. the concentration of a gas in a solution is directly proportional to the partial pressure of that gas in the adjoining air
- Note: temp. change how much gas a fluid holds, this is why global warming is increasing the pH of the ocean

Question 35

Rate of diffusion

Answer 35

is affected by the pressure gradient of the surface area, and the thickness of the barrier

Question 36

Fick’s Law

Answer 36

Diffusion of a particular gas at a given temp. is enhanced by a large surface area and a steep partial pressure gradient. It is reduced by a thicker barrier

Rate of diffusion = K * A * (P2-P1)/D

K = diffusion constant
A = area of gas exchange
P2-P1 = different in partial pressure of the gas
D = distance (thickness of barrier to diffusion)

Question 37

Haemoglobin

Answer 37

• saturation curves measure the % of haem units which are bound to O2 at different PO2
• its subuits exhibit cooperative binding of O2
• this keeps oxygen saturation (& this oxygen reserves relatively high air rest, even in systemic venous blood)