Respiration 1 Flashcards
What is the most critical function the respiratory system provides?
Providing oxygen
Need oxygen for the electron transport chain–>final electron acceptor
What are the 7 main functions of the respiratory system
- Provide Oxygen
- Eliminate Carbon Dioxide
- Regulate Blood pH
- Facilitate speech
- Microbial Defense
- Activate and Inactivate Chemical Messengers
- Defend Against Blood Clots
How does respiratory system regulate blood pH
The ventilation rate affects how much CO2 is released which in turn affects how much CO2 is in the plasma
Why do we need respiratory system for speech
When we say words air flows out of the mouth
We don’t suck in air when we speak
How does the respiratory system combat pathogens (3 major ways)
Coughing and sneezing: expel mucous that is loaded with pathogens
Epithelial secretions: respiratory tubes lined with epithelium secrete antibacterial substances
Lymphoid tissue: B and T lymphocytes cluster beneath the mucosal layer
What is an example of activation of chemical messengers by the respiratory system
Angiotensin I–> Angiotensin II
Angiotensin II stimulates aldosterone secretion
How does respiratory system prevent clot formation
The endothelial cells lining the capillaries secrete substances that promote protein lysis
Cause fibrolysis: break down fibers in clots and inhibit platelet aggregation
What are the three main components of the respiratory system
- Lungs
- Airways
- Mechanical aids
What is the main purpose for the airways
Series of tubes to exchange air between the lungs and the environment
Need a way for CO2 to leave the lungs and get out to the environment
What major process occurs at the lung and what is happening during this process
Site for gas exchange
O2 into the blood
CO2 out of the blood
What are the three different zones the airways are divided
- Upper Airways
- Conducting Zone
- Respiratory Zone
What are mechanical aids and what are they used for
Skeletal muscles
Help relax and contract the diaphragm to change the volume in the thoracic cavity
what structures make up the upper airway and where are they in relation to the thoracic cavity
mouth/nose, pharynx, larynx, upper trachea
these structures are outside the thoracic cavity
what structures make up the conducting zone and where are they in relation to the thoracic cavity
trachea and its branches -primary -secondary -tertiary bronchioles and terminal bronchioles
inside the thoracic cavity
what is characteristic of the tubules in the conducting zone to allow proper air flow
the tubules are not collapsible and stay open at all times
what zone of the airways do gas exchange occur
respiratory zone
conducting zone has no gas exchange
what is the trend regarding cartilage and smooth muscle in the conducting zone
Bronchi, as they get smaller, will lose cartilaginous rings and increase in smooth muscle
where are mucous glands present in the conducting zone?
in the bronchi but not in the bronchioles
as move down the tubules there are less and less mucous glands
what is a key thing that happens in the respiratory zone
gas exchange
what is characteristic about the respiratory zone that allows for gas exchange
thin walled respiratory bronchioles
what makes the tubules in the respiratory zone different from the tubules in the conducting zone
these tubules are collapsible
need to have air flowing through to keep them open
the structures of the respiratory zone
respiratory bronchioles
alveolar ducts
alveolar sacs
when initially inhaling air it is cold and dry, what does the respiratory system do to it?
heat and water vapor are exchanged with the blood in the airway walls to moisten and warm the air
what does branching structure do to the air flow rate
decreases resistance to flow
what are the two types of cells that are in the conducting zone that protect against microbes and how
goblet cells:
-secrete mucous that traps pathogens and airborne particles
ciliated epithelial cells:
-cillia on epithelial cells pulse upward to move mucous up and out of the larynx into the esophagus to be swallowed or expelled
“frog in throat”
how does the mucous produced by the goblet cells become watery so it can be easily moved up into the esophagus to eliminate microbes
there are Cl- channels in the tracheal cells that normally transport Cl- from the inside of the cell to the lumen of the trachea
Na+ goes with it
Extracellular fluid goes with it making the mucous more watery
what is cystic fibrosis
a disease that impairs normal function of the conduction zone
how does cystic fibrosis affect the normal function of the conducting zone
WHAT ARE 2 CONSEQUENCES OF CYSTIC FIBROSIS
mutation in genetic code for Cl- channel reduces the amount of Cl- and Na+ that moves into the lumen of the trachea
water does not follow and the mucous becomes thick, dry, and sticky
cilia cannot beat hard enough to move the mucous upwards
- infectious agents are trapped in the mucous but cannot be expelled–INFECTIONS
- airways obstruction
what are 3 functions of the conducting zone
- branching to decrease resistance to airflow
- microbial defense
- warm and moisten air
what are 3 functions of the respiratory zone
- regulate airflow
- site for gas exchange
- microbial defense
what is responsible for regulating airflow in the respiratory zone
the smooth muscles in bronchioles
how is airflow regulated in the respiratory zone
controlled by psymp and symp nervous system
sympathetic stimulation causes smooth muscle to relax and dilate bronchioles to increase air flow
how are alveoli modified to promote gas exchange (4)
- INCREASED SURFACE AREA
- HIGHLY VASCULARIZED:
- lots of capillaries - LOW RATE of BLOODFLOW
- provides time for gas exchange
- need time for O2 to be picked up by the blood
- low resistance to flow, low pressure - THIN SURFACES
- good diffusion of O2 from air into the blood
how does respiratory zone provide microbial defense
by pulmonary macrophages
what are the mechanical aids of the respiratory system
skeletal muscles and bones of the thoracic cavity
what are the main purposes of respiratory mechanical aids
do work of respiratory system
allows air to flow in and out of the lungs
bones provides protection to lungs
what are three types of cells found in alveoli
- type I cells
- type II cells
- macrophages
what is the main function of type I cells in alveoli
what is their structure like
gas exchange
squamous epithelial cells (pavement cells)
what is the main function of type II cells in the alveoli
secrete surfactant
what is surfactant and what does the secretion of this do for the lung
surfactant is a detergent like substance (mix of proteins and salts)
- keeps lungs from sticking to itself
- decreases surface tension
what are pulmonary macrophages and what is their function
immune cells that remove infected tissue in the lungs
what characteristics of the alveoli help with gas exchange
thin surface and small diameter
pulmonary capillaries
what does small diameter of alveolus do for gas exchange
allows for more gas to be in contact with the surface of the alveolus
what is the diameter of the alveolar sac
0.5 micrometers
what is the distance between the pulmonary capillary and the alveolus
0.2 micrometers
solubility diffusion rates O2 vs CO2
diffuse at different rates due to different solubilities
CO2=77mmol/L
O2=2.2mmol/L
CO2 more easily diffuses
diffusion of respiratory gases
- what decides the direction of diffusion
- describe polarity
respiratory gases are small non polar molecule
they diffuse along concentration gradient
they readily diffuse through membranes; do not diffuse as easily through bodily fluids
trace the path of diffusion of O2 from respiratory tubule to blood (name all the surfaces the gas must cross)
- cross plasma membrane on apical side of epithelial cell
- cross intracellular fluid
- cross basal membrane on other side of epithelial cell
- cross basal lamina which is where connective tissue is located where type I alveoli cells are attached
- cross extracellular fluid
GET INTO BLOOD VESSEL - cross basal side of endothelial cell
- cross intracellular fluid of endothelial cell
- cross apical membrane of endothelial cell
O2 now in blood vessel!
what are the “two layers” of the pleural sac
parietal: adheres to underside of thoracic wall and top of diaphragm
visceral: pleura covers outer surface of lung
what separates the two lungs
mediastinum
what is the space called between the “two layers”
pleural sac
how is airflow related to pressure difference and resistance to flow
airflow= change in pressure/resistance
directly related to change in pressure
indirectly related to resistance
what are the purposes of intrapleural fluid (3)
- lubricate surfaces: so when lungs expand, don’t rub on ribs
- subject to pressure changes when thoracic cavity expands or contracts
- controls volume of lung
ventilation relies on…
pressure differences between air in the lungs and air outside the lungs
how do we calculate change in pressure
pressure in alveoli minus pressure in atmosphere
describe air pressure inside lung and in atmosphere at inspiration
air pressure in lung is less than air pressure of atmosphere
describe air pressure inside lung and in atmosphere during expiration
air pressure in lung is more than air pressure of atmosphere
what causes pressure in the alveoli to change
change in volume of alveoli will change the air pressure if the molecules are constant
change in molecules but constant volume will change air pressure
are the lungs capable of changing volume
yes the lungs can stretch and recoil
what is the alveolar pressure
the pressure in the lung
what is the intrapleural pressure
pressure in the fluid in the intrapleural space
what is transpulmonary pressure
the difference between alveolar pressure and intrapleural pressure
important in inflation/deflation of the lung
what happens with muscles at the beginning of inspiration
diaphragm contracts which increases the volume of the thoracic cavity
external intercostals contract to lift rib cage further increasing the thoracic cavity
what happens with muscles at the beginning of expiration
the diaphragm relaxes which decreases the volume in the thoracic cavity (diaphragm domes up)
external intercostals relax lowering the rib cage and also decreasing the thoracic cavity (decrease volume)
what is the relationship between air pressure of alveoli and atmosphere between breaths
air pressure of alveolar and atmosphere equal each other (no air is moving)
what pressure is always negative and why
interpleural pressure
because chest wall tends to pull outward and lungs tend to recoil inward (opposite direction)
don’t want high pressure cause don’t want lungs to collapse
what happens to air pressure as diaphragm contracts and thorax expands
inspiration
interpleural pressure becomes more negative
makes transpulmonary pressure increase so lung will expand and pressure will decrease lower than atmospheric pressure therefore air will flow into the lungs until Palv=Patm again
what happens to air pressure as diaphragm relaxes and thorax compresses
expiration
interpleural pressure becomes less negative (increases)
transpulmonary pressure will then decrease so lung volume will decrease and pressure will increase higher than atmospheric air pressure therefore air will flow out of lung until Palv=Patm again
if additional muscles are involved other than diaphragm
forced expiration and forced inspiration
follow the pathway from beginning of inspiration to when air flows into the lungs
- diaphragm contacts
- thorax expands
- interpleural pressure decreases (more negative)
- transpulmonary pressure increases (Palv minus or more negative making more positive)
- lungs expand
- pressure in alveoli becomes less than atmospheric pressure
- air flows into lung
follow the pathway from beginning of expiration to when air flows out of the lungs
- diaphragm relaxes
- thorax compresses (chest wall recoils)
- interpleural pressure increases (becomes less negative)
- transpulmonary pressure decreases (Palv minus a less negative number)
- lungs recoil (compressed)
- pressure in alveolus increases above atmostpheric pressure
- air flows out of lungs
what causes pneumothorax
punctured lung
no longer different pressures
what happens to the lung and chest wall if pneumothorax
lung collapses; chest wall expands
can happen to just one lung while the other stays inflated
