Respiratory system Flashcards
why do we breath?
- to provide oxygen to all metabollically active cells and to get rid of carbon dioxide
- This is accomplished by BOTH the cardiovascular and respiratory systems
The way the respiratory system is set up it allows for
adequate gas exchange because of its surface area
the lungs must be _______, _______ and protected from ____________.
- thin
- moist
- pathogens
the respiratory system requires a pump to create pressure gradients why?
- gas flows from high to low pressure
- the lungs are a pump with the help of the diaphragm and intercostals
•Trachea divides many times until terminating in _________.
- alveoli
how does gas flow change with resistance?
•Gas flow changes inversely with resistance
The greatest resistance is found in trachea and bronchi, Why?
- because there is an increased air flow; turbulence.
- air is going in all different directions in spaces with large dimeters; because oxygen is a gas molecule and does not go in the direction of gravity
Lowest resistance is found in bronchioles why?
•greater overall cross-sectional area
what happens when the air reaches the capillaries of the lungs?
diffusion
Asthma attacks happen because of
bronchiole constriction
airways______and _______ and are lined with ____________.
- humidify
- filter air
- respiratory epithelium
where does gas exchange happen?
- in the alveoli
Alveoli means
- small cavity
the lung contains millions of ________.
Aveoli
aveoli are _______,________ and________
- soft
- spongy
- elastic
Alveoli are composed of a ____________________.
single layer of squamous epithelial cells
Aveolar surface is covered by a “cobweb” of ______________.
pulmonary capillaries
Capillaries are always in contact with the alveoli _______________.
Capillaries serve as air-bloodbarrier
in the aveoli gas exchange occurs by ____________.
simple diffusion
Macrophages in the aveoli ____________ we breath in.
eat pathogens
what are the types of lung surfactant cells?
- Type 1
- Type 2
Type 1 lung surfactant cells
allow for gas exchange
Type 2 lung surfactant cells
make and secrete lipids and proteins to keep aveoli patent
IRDS
- IRDS: infant respiratory distress syndrome usually occurs in premature babies because their lungs are not developed, their lungs do not have surfactant which causes the aveoli to collapse and cause difficulty breathing in a baby
what is in the air we breath?
- Nitrogen
- Oxygen
- Carbon dioxide
- water
•Air is a mixture of gases and each gas exerts a “pressure”______________ that is directly proportional to percentage of the gas in the mixture
- partial pressure
•Gases move down their ___________, and are influenced by _____________.
- pressure gradient
- volume changes
At sea level what is the percentage of nitrogen in the air, what is its partial pressure?
- 78.6%
- 597 mmHg
At sea level what is the percentage of Oxygen in the air what is its partial pressure?
- 20.9 %
- 159 mmHg
at sea level what is the percentage of carbon dioxide in the air and what is its partial pressure?
- 0.04%
- 0.3 mmHg
at sea level what is the percentage of water in the air and what is its partial pressure?
- 0.46 %
- 3.7 mmHg
all together what do the percentages of gases in our air at sea level adds up to what do their partial pressures add up to?
- 100.0%
- 760 mmHg
in the aveoli what percent of nitrogen is present and what is its partial pressure?
- 74.9%
- 569 mmHg
In the aveoli what is the percentage of oxygen in the air and what is its partial pressure?
- 13.7%
- 104 mmHg
In the aveoli what is the percentage of carbon dioxide in the air and what is its partial pressure?
- 5.2%
- 40 mmHg
In the aveoli what is the percentage of water in the air and what is its partial pressure?
- 6.2 %
- 47 mmHg
In the aveoli what is the percentage of in the air of all the gases togther and what is their partial pressure?
- 100.0%
- 760 mmHg
Gases travel…
from high to low pressure
Po2
Partial pressure of oxygen
Pco2
Partial pressure of carbon dioxide
Pn
Partial pressure of nitrogen
Ph2o
partial pressure of water
while breathing in this happens
- volume of the thoracic cavity increases which leads to a decrease in pressure
- Intercostal muscles and diaphragm contracts
- Diaphragm contracts and moves downward
breathing out this happens
- thoracic cavity volume decreases causing pressure to go up
- respiratory muscles relax
- Gases flow from high to low pressure
Molecular oxygen is transported
–Bound to hemoglobin (Hb)
–Dissolved in plasma (1.5%)
Gases do not dissolve well in __________.
- solutions
- think soda
what is oxygen called when it is bound to hemoglobin?
- oxyhemoglobin
Hb that has released oxygen
- deoxyhemoglobin
Many factors affect Hb-O binding
- blood pH
- temperature
- CO2 levels
allosteric binding
- after oxygen binds to one site other oxygen molecules begin to bind quickly until there is room for only one more oxygen molecule
- causes S curve in oxygen called Hb disassociation curve
A) This part of the graph tells you the partial pressure of O2 in the blood
B) This axis tells you how saturated hemoglobin is with oxygen. at 100% all four binding sites are saturated.
C) the more O2 in the blood (higer Po2) the more O2 is bound to hemeglobin. because of hemoglobins properties binding strength changes with saturation, resulting in an S curve on the graph instead of a straight line
D) in the lungs were partial pressure of oxygen is high 100 mmHg hemoglobin is almost fully saturated with O2 at 98%
E) in tissues where O2 partial pressure is low (40 mmHg) hemoglobin is less saturated with O2 (75%)
What is special about fetal hemoglobin?
fetal hemoglobin has a higher binding affinity for O2, not more binding sites. The structure of their hemoglobin is a little different
•Normal cells produce about_________each minute… same amount excreted by lungs!
- 200 ml of CO2
Blood transports CO2 in 3 forms
–Dissolved in plasma(7-10%)
–Bound to Hb àcarbaminohemoglobin (20%)
–As bicarbonate ions in plasma (70%)
why is so much carbon dioxide carried in the blood as bicarbonate?
because of the bicarbonate buffering system
what is the equation for the bicarbonate buffering system?
Bohr effect
Decrease in blood pH and increase in CO2 levels weakens the Hb-O bond and promotes oxygen release
Hb can also bind to________, making blood pH changes __________________
- hydrogen ions
- minimal
carbonic acid-bicarbonate buffering system
HCO3¯ ions leave the RBC, enter plasma and act as alkaline reserve
