Unit 10: Respiratory System Flashcards
Function (5)
Transport of O2 from the air into the blood.
Removal of co2 from the blood into the air
Control of blood acidity (pH)
Temperature Regulation
Line of defense against airborne particles
Anatomy: Lung Location (3)
Thoracic Cavity
Surrounded by the rib cage and the diaphragm
Order of Anatomy (Acronym)
Nose/Mouth Pharynx Larynx Trachae Bronchi Bronchioles Alveoli
The Pulmonary Artery
Branches exstensively to form a dense netwrok of capillaries around the alveoli
Structure of the Capillaries + Blood flow (3)
One endothelial cell thick
Blood flow slows down significantly
large crossectional area
O2 diffuses ____ capillaries and CO2 diffuses ___.
into
out
From capillaries to heart
Oxygen rich blood flows back to the heart through the pulmonary vein
From capillaries
Oxygen rich blood flows back to the heart through the pulmonary vein
How many alveoli in a healthy human lung?
3 million
Structure of Alveoli (2)
Walls are 1 cell thick
composed of alveolar type 1 cells
Alveolar Type II cells
secrete a liquid called surfactant that lines the alveoli
A large number of _____ surround the _____ in close proximity.
Capillaries
Alveoli
Region between the alveolar space and the capillary lumen
Respiratory membrane
R. Membrane (2)
0.3 microns
where gas exchange takes place
Macrophages and lymphocytes
Protect alveoli from foreign particles
Fibers (Type + Location)
Of elastin and collagen are present in the walls of the alveoli, around the blood vessels and bronchi
Pleural Membranes
Outside sticks to the ribs: Parietal Pleura
Inside sticks to the lungs: Visceral Pleura
Two layers of the pleural membranes form the
Interpleural space
Fluid between the membranes
Pleural fluid (10-15ml)
reduces friction between the two pleural membranes during breathing
Ribs (Motion)
Tend to spring outwards
Lungs (Motion)
Tend to recoil and collapse due to the presence of elastin
Pressure Inside the Lungs
Alveolar Pressure
760 mmHg
Pressure Outside the Body
Atmospheric Pressure
760 mmHg
Interpleural Space Pressure
756 mmHg
Chest wall and lungs move in opposite directions causing lower interpleural space pressure
Transpulmonary Pressure
Alveolar Pressure-Intrapleural Pressure
the difference in pressure across the alveoli holds the lungs open
In healthy lungs transpulmonary pressure is
positive and keeps the lungs and alveoli open
If AP and IP pressures were equal
The lungs will collapse
Boyle’s Law
Pressure and volume are inversly related
When pressure increases volume decreases and vice versa
Moving air in the lungs requires an
air pressure gradient
In order for air to move into the lungs (pressure gradient)
High pressure outside and a low pressure inside the alveoli
In order for air to move out (pressure gradient)
There is a high pressure in the lungs and a low pressure outside
In order to inhale or exhale
Alveolar pressure must change
Decrease alveolar pressure by
Increasing lung volume
Increasing Lung volume
Move diaphragm down and external intercostal muscles of the rib contract, lifting the rib cage up and out
Alveolar pressure drops to _ _ _ mmHg while EP is _ _ _ mmHg
759 mmHg
760 mmHg
air rushes into the lungs
the contrations of these respiratory muscles during inhalation is an
Active process
Inspiration relies on signals from the
respiratory center located in the brainstem and causes the muscle to contract
Mechanism of expiration
Depends on rest or exercise
Mechanism of Expiration: At rest
Diaghragm and external intercostal muscles simply relax.
Lungs recoil to their original size
Volume decreases causing alveolar pressure to increase above atmospheric pressure
Alveolic Pressure _ _ _ mmHg (expiration)
761 mmHg
Alveolic Pressure _ _ _ mmHg (expiration)
761 mmHg
Outside Pressure _ _ _ mmHg
760mmHg
Alveolic Pressure greater than atmospheric pressure
Air flows out of the lungs
During exercise
Air must be forced out of the lungs
Contraction of the following structure
Abdominal muscles and the internal intercostal muscles of the rib
Pressure in the lungs during exercise
763mmHg inside
760 mmHg outside
The stretchability of the lungs: the more stretchable
The more stretchable the more compliant
Volume change that occurs as a result of a change in pressure
compliance = change in volume/ change in pressure
Compliance determines
the ease of breathing
low compliance is a lung that is difficult to inflate
a high compliance is a lung that is easy to inflate but difficult to deflate
Compliance of the lung is influenced by
Amount of elastic tissue found in the walls of alveoli, blood vessles and bronchi
the surface tension of the film of liquid that is lining all the alveoli
Pulmonary Fibrosis
Scar tissue in the lungs caused by inelastic collagen deposits on the immune cells inability to clear substances like coal dust, air pollution and abestos that have been inhaled
scar tissue decreases compliance
Aging and Pulmonary Emphysema
Causes increased compliance
PE is a chronic condition produced by smoking which destroys the elastin fibers in the lungs
the presence of the fibers decrease compliance
Compliance increases significantly and without
without elastin fibers to help recoil the lungs exhalation even at rest is very difficult and requires muscle contraction
Elastic Tissue components + location
fibers of elastin and collagen are present in the walls of alveoli, blood vessels and bronchi
Fibers are arranged in
A specific geometrical arrangement where elastin fibers are easy to stretch but collagen fibers are not
Arrangement of the fibers contributes to
1/3 of the total compliance of “elastic behaviour” of healthy lungs
The more elastin
The less compliant the lungs
Surface tension
1/3 of the elastic behaviour of the lung
surface tension of the liquid film lining the alveoli
Pulmonary surfactant
Liquid substance produced by type 2 or great alveolar cells and consists mostly of phospholipids
Surfactant has a
hydrophobic tail and a hydrophilic head
Surfactant lies
on the surface at the air-water interface when added to water
phospholipid head groups are attracted to water molecules and will balance the inward forces w/ outward ones
forces are now equal in every direction and the water drop will flatten out due to the decreased surface tension
Pulmonary Surfactant + Infant respiratory distress syndrome
Babies born before 36 weeks gestation do not produce proper amounts of surfactant
their alveoli tend to collapse making it very difficult to breath causing infant respiratory distress syndrome
babies extend an incredible amount of energy trying to expand their lungs leading to exhaustion
Open heart surgery patients
Do not release a lot of surfactants as they find it difficult to take depp breaths leading to complications and repiratory issues
Maximum lung capacity
5L of air
Amount of air inhales depends on
health
age
level of activity
Spirometer
Device used to measure lung volumes and capacities
useful for diagnosing pulmonary diseases
Tidal Volume
Volume of air entering or leaving the lungs during one breath at rest (500 ml)
Inspiratory Reverse Volume
The maximum amount of air that can enter the lungs in addition to the tidal volume (2500 ml)
Expiratory Reverse Volume
The maximum amount of air that can be exhaled beyond the tidal volume (1000 ml)
Residual Volume
Volume remaining in the lungs after a maximal expiration (1200 ml)
Inspiratory Capacity
the maximum amount of air that can be inhaled after exhaling the tidal volume (tidal+ IRV)
Functional Residual Capacity
the amount of air still in the lungs after exhalation of the tidal volume (expiratory reverse volume + residual volume)
Vital Capacity
The maximum amount of air that can be exhaled after a maximal inhalation (inspiratory reverse + tidal volume + expiratory reverse volume)
Total Lung capacity
Maximum amount of air that lungs can hold (vital capacity +residual volume)
Respiratory Zone
Region in the lung where alveoli are located
Pulmonary Ventilation
Amount of air that enters all of the conducting areas + respiratory zones in 1 minute
Conducting Zone
Anatomical dead space
area in the lung where no gas exchange takes place
no alveoli
PV Determines
the amount of air/oxygen available to the body
VE =
Tidal Volume x Respiratory Rate
7500 ml/min at rest
Only air entering the
Respiratory zones is involved in gas exchange
Alveolar Ventilation
Volume of air entering only the respiratory zones each minute
volume of fresh air available for gas exchange
Alveolar Volume is
Difficult to measure
If tidal volume is 500ml approx. 150ml remains in the conduction zone where there are no alveoli
150 corresponds to the weight of the person in pounds
Alveolar Ventilation Equation
VA = VE - VD
Dead Space VD Equation
VD = dead space volume x respiratory rate
Partial Pressure
Pressure exerted by one gas in a mixture
Due to gas exchange
The actual value for alveoli PO2 is lower and PCO2 is much higher
Blood Entering the Lungs (Partial Pressure)
PO2 = 40 mmHg
PCO2 = 46 mmHg
Alveoli (Partial Pressure)
PO2 = 105 mmHg
PCO2 = 40 mmHg
As blood moves past the alveoli O2 will diffuse into the bloodstream and CO2 will diffuse into the alveoli
PO2 = 100mmHg
PCO2 = 40 mmHg
partial pressure equilibrate w/ the alveoli PO2 and PCO2
O2 and CO2 throughout the circulatory system
Blood leaving the lungs has a high PO2 (100 mmHg) and and a low PCO2
Blood returnss to the left side of the heart and is pumped through the systemic circulation.
Blood enters the tissue beds with the same PO2 and PCO2
Cells have a low PO2 (40 mmHg) and a high PCO2 (46 mmHg) inside
As blood flows through capillaries oxygen diffuses into the cells
very little oxygen is dissolved into the plasma
How is Oxygen transported in the blood
Carried by hemoglobin in RBC
Dissolved in plasma
Oxygen dissolved in plasma
Very little oxygen is transported in the blood dissolved plasma not enough to supply the bodies needs
1.5% of the total oxygen is carried by the protein hemoglobin in RBCs
15ml of oxygen dissolved in our plasma
require 250ml of oxygen
How much oxygen is carried by hemoglobin
98.5%
4 oxygen molecules
Red Blood Cell
Doughnut-shaped with a hole
just larger enough to squeeze single file through a capillary
no nucleus in their mature form
Number of RBCs in males or females
- 2 Million
4. 7 Million
RBC production
Erythropoiesis
120 day lifespan
250 million RBCs are produced every day
RBC Production Location + Requirements
Takes place in bone marrow
AA
Iron
Folic Acid
B12
RBC destruction
Destroyed and removed by the spleen and liver
Erythropoietin
Hormone control of erythrocyte production
90% secreted by the kidneys
10% by the liver
stimulates bone marrow to start producing RBCs
Erythropoietin is secreted in
Low amounts so RBCs secreted to keep up with loses
1250 mil. RBCs per day
Decrease in Oxygen
Increase in EPO
Lung disease
High Altitudes
Decrease in RBCs or total hemoglobin content
