Breathing and Gas Exchange. Flashcards
Respiratory Bronchioles are connected to alveoli along ______ _______.
Alveolar Ducts.
Where do alveolar ducts end?
At alveolar sacs.
Each alveolus has an extensive network of ____ and is surrounded by elastic fibres.
Capillaries.
What is found around bronchioles?
Smooth Muscle.
What is the smooth muscle around the bronchioles regulated by?
It’s regulated by Autonomic Nervous System (ANS).
How does the ANS regulate the smooth muscles around the bronchioles?
- It controls the diameter of the bronchioles
- It controls the airflow and resistance in the lungs.
________ is caused by sympathetic ANS Activation.
Bronchodilation.
What does bronchodilation do?
It reduces resistance.
What is Bronchoconstriction caused by?
Parasympathetic ANS Activation.
In Bronchoconstriction what is released?
Histamine.
_______ increases resistance in the lungs and is often caused by having an allergic reaction.
Bronchoconstriction.
What condition results from excessive stimulation (with sensitive and swollen airways) and bronchoconstriction (severely restricting airflow)?
Asthma.
Allergens and Irritants are triggers of ________.
Asthma.
Name some examples that would restrict airflow.
- Narrowed Airway
- Tightened Muscles
- Inflamed/thickened airway wall
- Excessive mucous.
What is the respiratory membrane?
The thin membrane of alveoli across which gas exchange takes place.
The _____ membrane; where gas exchange takes place, has 3 layers.
Respiratory
Name the 3 layers of the respiratory membrane.
- Squamous Epithelial Cells
- Endothelial Cells
- Fused basement membranes.
What do the squamous epithelial cells line?
The alveolus.
In the respiratory membrane, what do the endothelial cells line?
They line an adjacent capillary .
Where is the Fused Basement Membranes Layer found?
Between the alveolar and endothelial cells.
Is the respiratory membrane thick or thin?
Very Thin (for gas exchange).
What occurs across the respiratory membrane?
Diffusion/ Gas Exchange.
A network of what surrounds each alveolus?
A network of Capillaries.
A capillary network surrounds each _____, as part of the _________ membrane.
Alveolus, Respiratory.
Why is diffusion across the respiratory membrane very rapid?
- The distance is very short
- Gases (O2 and CO2) are lipid soluble
What is Pneumonia?
Inflammation of the lobules.
What does Pneumonia (inflammation of the lobules) cause?
- Causes fluid to leak into alveoli
- This compromises the function of the respiratory membrane.
Where do the respiratory exchange surfaces in the lungs receive blood from?
The arteries of the Pulmonary circuit.
Blood from the alveolar ______ passes through the Pulmonary venules and _____, and returns to where?
Capillaries. Veins. Returns to the left atrium.
All processes involved in exchanging 02 and CO2 with the environment is known as _____ respiration.
External.
______ respiration is the result of cellular respiration and involves the uptake of 02 and production of CO2 within individual cells.
Internal.
What is the fancy word for breathing?
Pulmonary Ventilation.
In external respiration, where does gas diffusion occur?
Across the respiratory membrane (from the alveoli to the capillaries).
In respiration, what 2 gases are exchanged?
O2 and CO2.
There is _____ transport between:
- alveolar capillaries
- capillary beds in other tissues.
Gas.
What does pulmonary (minute) ventilation refer to?
The volume of gas moved in and out of the lungs per minute.
What is ventilation measured in?
Litres per minute.
What is ventilation the product of?
The number of breaths per minute and the volume of each breath.
At rest, only two thirds of the volume of air breathed in reaches the _____ and is available for ____ _________.
Alveoli, Gas Exchange.
Only _______ of the respiratory minute ventilation volume reaches the _____ surfaces.
Two-thirds, alveolar.
______ ventilation refers to the portion of the minute ventilation that mixes with the air in the alveolar chambers.
Alveolar.
What is the volume of air remaining in conducting passages known as?
Anatomical Dead Space.
Define Alveolar Ventiation.
The amount of air reaching alveoli each minute.
With each breath, a proportion of the ______ air does not enter the ________.
Inspired, Alveoli.
What is the anatomical dead space?
The portion of inspired that remains in conducting passages (nose etc.) that doesn’t reach the alveoli.
How much of the resting tidal volume does anatomical dead space typically represent?
Around 30%.
Alveolar Ventilation is really important, what does it prevent?
It prevents drastic changes in alveolar air composition.
This maintains a relative consistency in arterial blood gases throughout the breathing cycle.
What enables us to assess static and dynamic lung volumes?
Spirometry.
What is Tidal Volume (Vt)?
The volume inspired and expired per breath (eg. 500/500ml).
The _____ ______ _______ is the volume in lungs after maximum inspiration.
Total Lung Capacity/Total Lung Volume.
What is the residual lung volume?
The Volume in lungs after maximum expiration.
What is the total lung capacity in males?
6000 mL (6 litres)
What is the total lung capacity in females?
4200 mL (4.2 litres)
The ______ ______ _______ is 1200 for males and 1100 for females.
Residual Lung Volume.
What is Inspiratory Capacity?
The maximum volume inspired after tidal expiration.
_____ ______ capacity describes the maximum volume of air that can be expelled from the lungs.
Forced Vital.
What volume is often stated as a percentage of Forced Vital Capacity, reflecting respiratory power and overall resistance to air movement in the lungs?
Forced Expiratory Volume (think “in the first second”/asthma test).
Heavy Exercise ______ breathing rate.
Increases.
Apart from breathing rate, what else does heavy breathing increase?
Tidal Volume and Minute Ventilation.
Even during heavy exercise, _____ _____ rarely exceeds 60-65% of lung capacity.
Tidal Volume.
What testing do we use to diagnose cardiovascular and pulmonary conditions?
Cardiopulmonary Health Tests.
When is it best to perform Cardiopulmonary Health Tests?
When the system is at stressed (eg. not at rest), therefore it is best to perform this test during exercise.
The net rate of gas diffusion across the membrane obeys what law?
Fick’s Law.
The net rate of gas diffusion across the membrane obeys Fick’s Law, and depends on the _____ _____ between the two sides of the _____ _____ and the _____ ______ of the membrane.
Pressure Difference, respiratory membrane, diffusion capacity.
The rate of transport of a gas from alveolar air ______ with increased surface area.
Increases.
The rate of transport of a gas from alveolar air increases with the molecule’s ______/_____.
Diffusivity/Solubility.
The thicker the membrane the ____ the rate of transport.
Slower.
What does the body’s oxygen supply depend on?
The oxygen concentration in ambient air and its pressure.
In physiology, we refer to the Partial Pressure of the individual gases, computed as what?
% concentration x total pressure of gas mixture.
What determines different partial pressures and solubilities?
Direction and rate of diffusion of gases across the respiratory membrane.
What does “Low P O2” mean?
Low partial pressure of oxygen.
What are the partial pressures of blood arriving in pulmonary arteries at the site of gas exchange?
Low P O2
High P CO2
The concentration gradient between the alveolar capillaries and alveolar air causes what?
O2 to enter blood.
CO2 to leave the blood.
Rapid exchange of gases allows what?
Blood and alveolar air to reach equilibrium.
The newly oxygenated blood mixes with deoxygenated blood from conducting passageways, what does this do?
Lowers the partial pressure of O2 in blood, entering the systemic circuit.
In the systemic circuit, where does 02 diffuse from and to?
It diffuses from peripheral capillaries (high 02 conc) into intertestital fluid (low O2 conc).
Amount of O2 released (from peripheral capillaries) depends on what?
Interstitial P 02.
The concentration gradient in peripheral capillaries is the ________ of the lungs. CO2 diffuses ____ blood and 02 diffuses _____ blood.
Opposite. Into, Out of.
Blood from tissues goes to the ______ capillary, this blood has more _____ than _____.
Pulmonary, CO2, O2.
Blood to tissues goes from the _______ capillary, it has a higher concentration of _____ than _____.
Pulmonary, O2 CO2.
There is a large _____ difference in 02 _____-______ gradient.
Pressure, Alveolus-Capillary.
What guarantees the diffusion of CO2?
The solubility of CO2 in blood plasma is about 25 times higher than O2.
The blood plasma alone can’t transport enough O2 or CO2 to meet psychological needs. What structure is involved in transport?
Red blood cells.
Where to red blood cells transport O2 to/ CO2 from?
Transport O2 to peripheral tissues and CO2 from the peripheral tissues.
Red blood cells remove O2 and CO2 from _____, what does this allow?
Plasma, Allows gases to diffuse into blood.
What does 02 bind to?
It binds to iron ions in haemoglobin molecules.
The binding of O2 to haemoglobin is a _____ reaction.
Reversible.
How many O2 molecules can bind to 1 haemoglobin unit?
4.
When oxygen is bound to haemoglobin, what is this known as?
Oxyhaemoglobin.
98 % of O2 is bound to ______ for transport in blood.
Haemoglobin.
What is deoxyhaemoglobin?
Haemoglobin with no O2 Bound to it.
The fraction of haemoglobin in the form of oxyhaemoglobin is expressed as the ____ ___________. (amount of O2 bound to Hb/ Max Hb amount x 100)
% saturation.
What uses infrared diodes to calculate the ratio of oxyhaemoglobin and deoxyhaemoglobin?
Pulse Oximetry. (thing dad has to put on finger)
What does % saturation normally range between?
95% to 99%.
Name the graph that relates saturation of haemoglobin to partial pressure of O2.
Oxygen-Haemoglobin Saturation Curve.
The higher the P O2 the ______ the haemoglobin saturation.
Greater.
Why is the saturation curve a curve?
Because haemoglobin changes shape each time anther molecule of O2 is bound, making it easier fort the next molecule to bind, aka. affinity is increased.
Name the factors that the affinity of Haemoglobin to Oxygen depend on.
- P O2 of blood
- Blood pH
- Temperature
- Metabolic activity within Red Blood Cells.
The standardised/optimum conditions for normal blood is pH __ and _____ degrees(Celsius).
pH 7.4, 37 degrees
If pH drops (becomes more acidic), What happens?
More O2 is released, Curve shifts to the right.
If Temperature rises, _____ O2 is released and the curve shifts ______.
More, Right.
If pH rises, less oxygen is released. What way does the curve shift?
Left.
If Temperature _____, less oxygen is released and the curve will shift left.
Drops.
What dangerous gas binds very strongly to haemoglobin (more so than O2) and what can this result in?
Carbon Monoxide.
Can result in Carbon Monoxide Poisoning.
O2 goes from the atmosphere all the way to the alveoli, then to the _______ _______, this takes the oxygenated blood to the ____ side of the heart, this pumps oxygenated blood to _____ _______ which then go to body _____.
Pulmonary Capillaries, Left, Tissue Capillaries, Cells.
What is the most effective means of increasing alveolar ventilation?
By breathing Deeply and Slowly.
What does breathing deeply and slowly ensure?
That air reaches a sufficient number of perfused alveoli so that O2 and CO2 can be exchanged.
What breathing is not good/ can act as a warning sign?
Shallow rapid breathing.
Pulmonary ventilation and circulation are ______. What does this ensure?
Co-ordinated.
-Ensures efficient exchange of gases
The coordination of pulmonary ventilation and circulation helps to maintain ______ and ensure sufficient oxygen reaches the ______.
Homeostasis.
Tissues.
CO2 travels from the body ____, to tissue ____, then to the _____ side of the heart where the deoxygenated blood is pumped to the pulmonary ______, this then reaches the ______ where CO2 is then released into the ________.
Tissues, Venules, Right, Venules, Alveoli, Atmosphere.
CO2 is transported in blood in 3 ways:
- Dissolved in _____ (7%)
- Bound to _______ (23%)
- ________ ions (70%)
Plasma
Haemoglobin
Bicarbonate
CO2 enters Red Blood Cells in the capillaries, where it combines with water to form what?
Carbonic Acid.
What happens to the Carbonic Acid?
It is catalysed (by carbonic anhydrase) to form bicarbonate ions and hydrogen ions.
The hydrogen ions released from the bicarbonate reaction bind to __________. What does this keep constant?
Deoxyhaemoglobin. Keeps blood pH constant.
What is blood pH regulated by (apart from Hydrogen ions)?
By ventilation.
An increase in ventilation causes exhalation of additional _____.
CO2.
What does an increase in ventilation do to CO2 concentration?
The partial pressure in blood reduces and it lowers H+ concentration (hyperventilation).
If H+ concentration increases it will cause an ____ condition in the blood known as ______.
Acidic, Acidosis.
What is acidosis caused by?
Hypoventilation.
Hypoventilation means breathing is ______ than normal, it causes the accumulation of ____ in tissues, the pH to _____ and Plasma HCO-3 _____.
Slower, CO2, Decrease (become more acidic), Increases.
In respiratory alkalosis, what happens to the pH of the blood?
The pH increases.
What is alkalosis caused by?
Hyperventilation.
Alkalosis refers to the excessive loss of what?
CO2.
In alkalosis the pH _____ and the plasma HCO-3 ________.
Increases, Decreases.
Breathing too fast is known as what?
Hyperventilation.
