4610 - LAB 13 Respiratory/Spirometry

virtual + handout

tidal volume

volume of one breath / amount of air moved into and out of lungs during quiet breathing (breathing without effort)

expiratory reserve volume ERV

amount of air moved out of lungs during forced exhale beyond level of tidal expiration

inspiratory reserve volume IRV

amount of air moved into lungs during forced inspiration beyond level of tidal inspiration

FEV 1.0 aka forced expiratory volume in one second

volume of air moved out of lungs in the first second of a forceful expiration following a maximal inspiration

inspiratory capacity IC

maximum amount of air that can be inspired after normal inspiration
IC = TV + IRV

vital capacity VC

maximum movable amount of air contained by lungs

VC = TV + IRV + ERV

FEV 1.0%

FEV 1.0 / VC x 100%
common comparison of fev 1.0 to vc

spirometer measures _________. lung volume can be calculated by knowing one of two specific absolute volumes _______ and _______

how lung volume changes but doesn’t directly measure its absolute volume

lung volume can be calculated by knowing one of two specific absolute volumes: residual volume RV or functional residual capacity FRC

residual volume RV

amount of air remaining in lungs at end of forced expiration.
typical RV = 1.2 L

functional residual capacity FRC

amount of air left in lungs after normal expiration
FRC = RV + ERV
typical FRC = 2.5 liters

forced expiratory flow 25-75

average flow rate of middle half of FVC

forced vital capacity

total amount of air forcefully exhaled from fully inflated lungs

can lung volumes vary?

yes, with age and sex

it’s possible for a person to have both obstructive and restrictive disorders simultaneously. what would you expect in the lab data of a person with both of these disorders?

reduced lung volume with reduced air flow

function - respiratory system allows for ______

respiratory system allows for gas exchange between air and blood providing oxygen used by body cells during aerobic respiration while expelling carbon dioxide waste

respiratory system consists of passages collectively called the ______ and the _______

respiratory system consists of passages collectively called the respiratory tract and the lungs

components of the respiratory tract are categorized into the _____ / _____ tracts. the upper includes? the lower includes?

components of the respiratory tract are categorized into the upper and lower respiratory tracts.

upper tract (5) = nose, nasal cavity, pharynx, larynx

lower tract (2) = trachea and passes in the lungs such as bronchi, terminal bronchioles

inspiration and expiration explaineda

• air flow is determined by differences in intrapulmonary and atmospheric air pressures

• air flows down its pressure gradient from high to low pressure. it goes to low

• respiratory muscles change the thoracic cage volume

• leads to intrapulmonary pressure changes with respect to atmospheric pressure

• leads to air flowing down the pressure gradient

the movements of oxygen and carbon dioxide follow ______ law. explain gas exchange

henry’s law

gas will diffuse down its partial pressure gradient from high to low pressure.

alveolar gas exchange occurs across respiratory membrane in lungs

oxygen diffuses from alveolar air into blood

carbon dioxide moves in opposite direction from blood to alveolar air

this oxygenated blood leaves the lungs and travels to body cells to deliver oxygen / pick up carbon dioxide waste

systemic gas exchange occurs between blood / cells of systemic tissue

oxygen diffuses from the blood to systemic cells

carbon dioxide moves in opposite direction from systemic cells to blood

this deoxygenated blood leaves the tissues and travels to the lungs to expel carbon dioxide and pick up oxygen

explain gas transport in the blood

oxygen is transported in the blood in 2 ways

• bound to hemoglobin forming oxyhemoglobin 98%

• dissolved in plasma 2%

carbon dioxide transported in blood in 3 ways

1. converted to bicarbonate, which is transported in plasma (80-90%)

2. bound to hemoglobin to form carbaminohemoglobin 5-10%

3. dissolved in plasma 5-10%

events of one respiratory cycle (8)

1. mechanisms of inspiration

2. alveolar gas exchange - oxygen moves into blood

3. oxygen transport in the blood

4. systemic gas exchange - oxygen moves into systemic cells

5. systemic gas exchange - carbon dioxide moves into blood

6. carbon dioxide transport in the blood

7. alveolar gas exchange - carbon dioxide moves into alveoli

8. mechanisms of expiration

respiratory tract

passageway for air between external environment and the alveoli of the lungs

conducting zone

parts of respiratory system that conduct air but don’t participate in gas exchange

respiratory zone

parts of respiratory sx that participate in gas exchange with the blood including respiratory bronchioles, alveolar ducts, alveoli

alveoli

small air filled pockets located along bronchioles / alveolar ducts

forms clusters

pulmonary ventilation

movement of air into / out of lungs

air flow

movement of air proportional to the pressure difference between 2 points and inversely proportional to resistance

atmospheric air pressure

air pressure in external environment

usually 760 mmHg at sea level aka 1 atm

intrapulmonary alveolar pressure

air pressure within the alveoli

intrapleural pressure

pressure between visceral / parietal pleurae, has a negative value relative to atmospheric / intrapulmonary pressures

visceral pleura = attached to lung surface

parietal pleura = attached to thoracic wall

pleural cavity = space between pleurae, contains serous fluid

transpulmonary pressure

difference between intrapulmonary pressure and intrapleural pressure

net pressure keeping the lungs inflated

boyle’s law

the pressure of a given quantity of gas is inversely proportional to its volume

• the volume of a container increases, and the pressure inside it decreases

partial pressure

pressure exerted by each gas in a mixture measured in mmHg

henry’s law

the amount of gas that dissolves in water is determined by solubility and partial pressure in the air

define hemoglobin

define globin, heme, oxyhemoglobin, deoxyhemoglobin, carbaminohemoglobin

protein found in RBC that carris oxygen / CO2.

has 4 globin subunits each bound to a heme group

globin = protein subunit of hemoglobin bound to a heme group

heme = pigment molecule bound to each globin protein, each heme contains iron atom and can bind to an oxygen molecule

oxyhemoglobin = hemoglobin bound to oxygen

deoxyhemoglobin = hemoglobin not bound to oxygen

carbaminohemoglobin = hemoglobin bound to carbon dioxide

2,3 biphosphoglycerate aka 2,3 BPG

metabolic intermediate produced in RBC promotes oxygen release from hemoglobin

many hormones (thyroid, growth, epinephrine) induce BPG synthesis affecting oyxgen delivery to body tissues

oxygenated blood

blood is maximally loaded with oxygen

appears bright red

deoxygenated blood

some oxygen has been removed from blood by systemic gas exchange

dark red

carbonic anhydrase aka CAH

enzyme in RBC that catalyzes this reaction:

CO2 + H2O = H2CO3 (carbonic acid)

carbonic acid then dissociates into H+ and HCO3 (bicarbonate)

bicarbonate aka HCO3-

product of carbonic acid dissociation and the major way carbon dioxide is transported in blood

chloride shift

antiport (active transport) of bicarbonate and chloride

occurs across RBC plasma membrane during alveolar / systemic gas exchange

by exchanging anion for an anion, chloride shift maintains electroneutrality across the plasma membrane

flow and obstructive lung disorders

Obstructive lung disorders result in a flow that is less than it should be

aka low flow

flow and restrictive lung disorders

Restrictive lung disorders have normal flow but low vital capacity and low inspiratory / expiratory volumes.