Respiration Flashcards
law of partial pressures
total pressure exerted by a mixture of gases is the sum of individual pressures exerted by each component gas in the mixture
partial pressure
the individual pressure exerted by any particular gas in a gas mixture
universal gas law
PV = nRT
mole fractional concentration
the fraction of total moles of gas present represented by the gas in question
volume fractional concentration
the fraction of the total volume represented by that particular gas
tension
partial pressure when speaking of gases in aqueous solution
absorption coefficient (A)
the dissolved concentration of a gas when the partial pressure of the gas in solution is 1atm A = Cx/Px (concentration / partial pressure of gas); a measure of gas solubility
convective transport/transport by bulk flow
occurs when a gas mixture or an aqueous solution flows and gas molecules in the gas/liquid state are carried by the fluid flow
unidirectional flow
ex. blood vessel
tidal flow
back and forth flow ex. lungs
standard conditions of temperature and pressure (STP)
T = 0 degrees Celsius (273K)
P = 1atm = 101kPA = 760mmHg
1 mol gas = 22.4L
ram ventilation
fish holds mouth open while swimming forward, water is “rammed” into its buccal cavity and across its gills
gas exchange membrane/respiratory exchange membrane
a thin layer of tissue consisting of 1-2 epithelia, separates the internal tissues of the animal from the environmental medium
external respiration/breathing
process by which oxygen is transported to the gas exchange membrane from the environmental medium and by which CO2 is transported away from the medium into the environmental medium
ventilation
bulk flow/convection of air/water to and from the gas-exchange membrane during breathing
gills
respiratory structures that are evaginated from the body and surrounded by environmental medium
lungs
respiratory structures that are invaginated into the body and contain the environmental medium
brachial
refers to structures/processes associated with gills
pulmonary
refers to structures/processes associated with lungs
external gills
located on an exposed body surface & project directly into the surrounding environment
internal gills
enclosed within a superficial body cavity
active ventilation
generation of ventilatory currents that flow to-and-from the gas exchange membrane (requires metabolic energy): unidirectional, tidal, nondirectional
passive ventilation
environmental air/water currents directly or indirectly induce flow to and from the gas exchange membrane
unidirectional active ventilation
pumped over the gas-exchange membrane in a one-way path
tidal active ventilation
air/water alternately flows to and from the gas-exchange membrane via the same passages
nondirectional active ventilation
air/water flows across gas-exchange membranes in many directions
diffusion lungs
lungs that exchange gases with the environment by diffusion only
dual breather/bimodal breather
animal that can breathe from air or water, usually have 2 distinct respiratory structures
cocurrent gas exchange
medium flows along the gas-exchange membrane in the same direction as the blood
countercurrent gas exchange
medium and blood flow in opposite directions
cross-current gas exchange
blood flow breaks up into multiple streams, each of which undergoes exchange with the medium along just part of the path followed by the medium
oxygen utilization coefficient
% oxygen in inhaled medium that an animal removes before exhaling the medium
continuous breathing
each breath is promptly followed by another in a regular, uninterrupted rhythm
intermittent breathing/periodic breathing
breathing in which breaths or sets of breaths are regularly interrupted by extended periods of apnea (periods of no breathing)
gill slits
lateral pharyngeal openings, a way to communicate with the environment
operculum
protective external flap that covers the gills on each side of the head
gill arches
run dorsoventrally between the gill slits, reinforced with skeletal elements, provides support for gills
gill filaments
2 in v-shape from gill arches, separates the buccal cavity on the inside from the opercular cavity on the outside
secondary lamellae
folds on gill filament, principal site of gas exchange
buccal pressure pump
develops positive pressure in the buccal cavity, forces water from buccal cavity, through the gill array, into the opercular cavity
opercular suction pump
develops negative pressure in the opercular cavity and thus sucks water from the buccal cavity into the opercular cavity
unicameral
a single sac with an open, undivided central cavity that provides access to any side compartments that may be formed by the folding of the walls
passive components of exhalation
not involving contraction of muscles, forces involving elastic rebound
active components of exhalation
forces developed by muscular contraction
multicameral
lung has multiple chambers
conducting airways
not involved in gas exchange, constitute the lung’s anatomical deadspace
respiratory airways
where gas exchange occurs, single layer of thin epithelial cells that is richly supplied with blood capillaries
tidal volume
volume of air inhaled/exhaled per breath
expiratory reserve volume
maximal volume of air that an individual can expel beyond the resting expiratory level
inspiratory reserve volume
maximal volume of air that can be inhaled beyond the resting inspiratory level
vital capacity
maximal tidal volume (TV + ERV+ IRV)
diaphragm
a sheet of muscular and connective tissue that completely separates the thoracic and abdominal cavities
external intercostal muscles
contraction expands thoracic cavity
internal intercostal muscles
contraction decreases thoracic cavity
relaxation volume
equilibrium volume of lung/thoracic wall when free of external forces
carotid bodies/aortic bodies
chemoreceptive bodies outside the CNS that detect hypoxia
pre-Botzinger complex
neuron cluster in ventrolateral medulla of brainstem - generation of breathing rhythm
respiratory minute volume (mL/min)
Vt (mL/breath) * f (breaths/min)
alveolar ventilation rate/alveolar minute volume
rate at which new air is brought into the alveoli and other respiratory pathways
mesobronchus (bird lung)
the primary bronchus that enters each lung and passes through the lung
secondary bronchus (bird lung)
2 groups that arise from mesobronchus (anterior and posterior group)
tertiary bronchi/parabronchi (bird lung)
small tubes connecting anterior and posterior secondary bronchi, gives off air capillaries that are surrounded by blood capillaries and are the site of gas exchange
air sac (bird lung)
part of the breathing system, located outside the lung, anterior and posterior sacs
neopulmonal system
developed system of parabronchial tubes running directly between the posterior air sacs and the posterior parts of the mesobronchi and posterior secondary bronchi (secondary to the paleopulmonal system)
respiratory pigments/oxygen-transport pigments
ex. Hb, undergo reversible combination with oxygen
metalloproteins
proteins that contain metal ions and function to increase the amount of oxygen that can be carried by a unit volume of blood
oxygen-carrying capacity
total amount of oxygen carried by each unit of volume
heme
metalloporphyrin containing iron in the ferrous state
myoglobins
muscle hemoglobins
hemocyanin
2nd most common class of respiratory pigments, found in arthropods and molluscs, one oxygen binds per 2 copper molecules
chlorocruorins
resemble hemoglobins and occur in certain annelids
hemerythrins
iron-based but do not contain heme
oxygen equilibrium curve/oxygen dissociation curve
shows the functional relation between the % of binding sites that are oxygenated and the oxygen partial pressures
percent saturation
% of binding sites that are oxygenated
volume percent
the volume of gas carried per 100 volumes of blood
blood oxygen utilization coefficent
% of arterial oxygen that is released to the systemic tissue
venous reserve
amount of oxygen mixed in venous blood
critical venous oxygen partial pressure
the venous oxygen partial pressure below which aerobic catabolism becomes impacted
Hill coefficient
index of cooperativity (1=no cooperativity, >1=high cooperativity)
P50
partial pressure of oxygen at which a pigment is 50% saturated
fixed Bohr effect
influences of proton on respiratory pigment molecules
CO2 Bohr effect
immediate influences of increased PCO2
Root effect
increased CO2 and H+ decreases the oxygen-carrying capacity of the respiratory pigment
2,3-bisphosphoglycerate (BPG, 2,3-BPG, 2,3-DPG)
organic modulator that reduces oxygen affinity of Hb, organophosphate produced in RBC
carbamate groups
CO2 on amino groups of Hb and other blood proteins
chloride shift
chloride diffuses into cells as HCO3- diffuses out of RBC via rapid anion exchange protein
respiratory alkalosis
exhalation of CO2 is abnormally increased relative to CO2 production
respiratory acidosis
exhalation of CO2 is impaired and metabolically produced CO2 accumulates excessively
metabolic acidosis
excessive loss of HCO3-
metabolic alkalosis
abnormally high HCO3-
rate of diffusion
diffusion coefficient * surface area * concentration gradient
pneumothorax
air in the chest/pleural sac causes lung to collapse on itself as air bubbles expand
neonatal respiratory distress syndrome
difficulty taking first breath due to lack of pulmonary surfactant
at rest, pressure in the pleural sac is:
-4mmHg
during inhalation, pressure in pleural sac becomes:
-5mmHg (causes lung expansion and pressure drop in lung)
during exhalation, pressure in pleural sac becomes:
-3mmHg (causes lung collapse and pressure rises in the lung)
bird lungs
- cross-current gas exchange
- contain air sacs (accessory structures)
- unidrectional flow through the parabronchi
amphibian lung
- unicameral lung
- fill lungs by buccopharyngeal pressure
tracheal system (insects)
system of air-filled tubes (trachea) that run throughout the body and are open to the outside world via spiracles (openings)
closed tracheal system (aquatic insects)
has tracheal gill instead of spiracles (openings)
hydrofuge hairs (aquatic insects)
gases can diffuse into hairs, traps air bubble alongside hydrofuge hairs which provides an air supply for submersion
book lung (spiders)
thin lamellae separated by air spaces, enters by spiracle, to atrium, to air spaces, to lamellae
branchial breathing system (teleost fish, gills)
- water crosses from buccal cavity, across gills, to opercular cavity
- buccal-opercular pumping
ram ventilation (fish)
open mouth and opercular, swim forward so that water just passes through and moves across gills
Fick’s Law
rate of diffusion = diffusion coefficient * surface area * partial pressure gradient for gases (concentration gradient)
Dalton’s Law
total pressure = P1 + P2 + P3
total pressure =
gas pressure + vapour pressure
Px =
(total pressure - vapour pressure) * (% of gas in mixture)
BTPS
body temperature and pressure, saturated with water
ATPS
ambient temperature and pressure, saturated with water
STPD
standard pressure (0 C) and standard pressure (atmospheric), dry
Bunsen solubility coefficient (alpha, absorption coefficient)
captures how readily a gas dissolves in a particular liquid
depends on: type of gas, liquid (salinity), temperature
amount of gas dissolved =
solubility coefficient * partial pressure * volume
V/Q matching
need to match ventilation of structures with perfusion (bloodflow)
bronchiolar smooth muscle
controls air flow into the alveolus, increased CO2 causes smooth muscle relaxation
vascular smooth muscle (leading up to alveolus)
sensitive to O2, low O2 causes constriction to reduce bloodflow
high altitude pulmonary edema
blood pressure in lungs become very high due to vascular smooth muscle constriction, causes fluid to leak out of blood vessel, “water in the lung”, caused by low partial pressure of O2
resting rate of O2 transport
250mL/min
Hb affinity for O2 is reduced by:
- heat
- organic phosphates
- pH decrease
- CO2
root effect/root shift
decrease in CAPACITY of Hb to carry O2 (downward shift)
Haldane effect
Hb with low O2 can bind more CO2 and H+
rapid anion exchanger
prevents HCO3- accumulation inside the cell
effect of HCO3- excretion by kidneys
increase H+, decrease pH
effect of H+ excretion by kidneys/gills/skin
decrease H+, increase pH
peripheral chemoreceptors
- O2 sensors, only detects very low O2 levels
- aortic arch (blood coming out of heart and being sent to body) and carotid arteries (blood going to the brain)
central chemoreceptors (CNS)
- CO2/pH sensors
- dominant control element
what can cause lungs to have decreased diffusive surfaces/diffusive limitation in lung/gill
emphysema, pneumonia
at extreme altitudes:
% O2 is constant but very low pressure, thus not enough driving force for air to enter lungs
hypercapnia
high CO2 in blood, caused by hypoventilation, lung diffusion limitations, respiratory acidosis
hypocapnia
low CO2 in blood, caused by hyperventilation, respiratory alkalosis