Respiratory System Flashcards
Where are the lungs located?
- in the thoracic cavity
- each contained in a separate chamber
What separates the two chambers that contain the lungs?
the mediastinum
What kind of membranes covers the lungs?
pleural membranes
What are the two kinds of pleural membranes covering the lungs?
Parietal pleura and Visceral pleura
Parietal pleura:
lines thoracic cavity
Visceral pleura
covers the lungs
What is the pleural cavity?
the space between pleural membranes
The pleural cavity contains what?
- filled with fluid
- negative pressure
What is the function of the fluid filling the pleural cavity?
- prevent friction
- causes membranes to adhere to one another
What is the function of the negative pressure in the pleural cavity?
- draws the air that you breathe into your lungs
- aids in inhalation
What is the hilus?
the region where blood vessels, nerves, and bronchi enter/exit the lungs
What do the lungs contain?
- pleural cavity
- pleural membranes
- hilus
- alveolar ducts
- alveoli
Alveolar ducts
arise from bronchioles
What kind of tissue makes up the alveolar ducts?
simple squamous
Alveoli
Small sacs at the ends of alveolar ducts
Alveoli characteristics
sites of gas exchange
Look like clusters of grapes.
Large surface area (70-140 m2 )
Closely associated with pulmonary capillaries
Secrete surfactant
What is the function of surfactant?
reduce the surface restriction at the air-liquid interface
What waste product is produced by gas exchanges?
CO2
Pulmonary ventilation
exchange of gases between the atmosphere and the lungs
Pulmonary ventilation requires what?
muscles/ATP
Pulmonary ventilation involves what two processes?
inhalation and exhalation
What are the two types of respiration?
external and internal respiration
External respiration
gas exchange between the lungs and the blood (diffusion)
What is external respiration on a molecular level?
exchange between gases in alveoli and gases in pulmonary capillaries
Internal respiration
gas exchange between blood and tissues (diffusion)
What is internal respiration on a molecular level?
between systemic capillaries and all the cells and tissues in the body
Air flows due to what?
pressure gradients
What must the pressure be to inhale?
Pressure in lungs must be less than atmospheric
When pressure inside is less than atmospheric, air enters into lungs
What causes the decrease in pressure during inhalation?
by increasing the volume of the lungs
Inhalation follows what gas law?
Boyle’s law
Boyle’s law
pressure and volume are inversely related
- As volume increases, pressure decreases
- As pressure increases, volume decreases
The change in volume during inhalation is achieved by what?
- Contraction of the diaphragm
- Contraction of external intercostal muscles
- Accessory muscles
Contraction of the diaphragm is responsible for what?
responsible for the change in volume
Contraction of diaphragm: inhalation
Pulls lungs downward
(expands thoracic/chest cavity vertically)
The contraction of the diaphragm does most of the work when?
Does most of the work when the body is at rest (75%)
Contraction of external intercostal muscles (25% of work)
expands chest/thoracic cavity front to back/horizontally
Pulls ribs & lungs outward and upward
What accessory muscles assist in the change of volume during inhalation?
Sternocleidomastoids, scalenes, pectoralis minor
When does exhalation occur?
Occurs when pressure in the lungs is greater than atmospheric
Exhalation is what kind of process?
Passive process at rest (no need energy/ATP/muscles relax)
Breathing out: The pressure in the lungs being greater than the pressure in the atmosphere is due to what?
Due to elastic recoil of lungs when diaphragm relaxes
Exhalation is assisted by what accessory muscles during what activity?
During exercise, is aided by internal intercostals and abdominals (pushes up)
Gases exchanges within the body (internal and external respiration) are what kind of processes?
- passive (simple diffusion from here on out)
- obey gas laws
Dalton’s law (law of partial pressure)
Each gas in a mixture exerts its own pressure as if all other gases are not present
Pressure of each gas is called a partial pressure
Total pressure of the mixture is calculated by adding the partial pressures of all gases present
What is atmospheric pressure (amount)?
760 mmHg
The atmosphere is composed mainly of what gas?
nitrogen
Henry’s law
- Solubility of gases in solution
- The amount of gas that will dissolve in a solution (plasma) at a constant temperature is dependent upon:
- Partial pressure of the gas- ## Solubility: how well does the gas go into solution
Solubility of gases
O2 is only partly soluble
CO2 is 24x more soluble
N2 is barely soluble and does not affect us under normal conditions
External respiration process (actually)
O2 diffuses from air into the blood (pulmonary capillaries)
CO2 diffuses out of the blood into the air
Oxygen transport: plasma
O2 is not very soluble in water/plasma
This is approximately 1.5% of the O2-carrying capacity of the blood
What components are enough to support regular metabolism?
RBCs/hemoglobin
What increases the oxygen-carrying capacity?
hemoglobin
Each hemoglobin can carry how many oxygen molecules?
4
RBCs/hemoglobin accounts for how much blood carrying capacity?
98.5%
RBCs/hemoglobin: total O2 to blood
20 ml O2 per 100 ml of blood or 1L in 5L of blood
Fully saturated
When all of the oxygen binding sites on the hemoglobin are filled with oxygen
- hemoglobin either has all 4 or none at all
Partially saturated
When blood contains a mixture of saturated and deoxygenated hemoglobin
Percent saturation
the average saturation of hemoglobin with oxygen
What is the percent saturation dependent on?
partial pressure
What is the effect of higher partial pressure on percent saturation?
higher saturation percent (up to 100%)
When is 100% saturation good?
100% saturation is good at lungs
When is 100% saturation bad?
bad at tissues because no O2 was delivered/high affinity
The lower the oxygen partial pressure, the __________ amount of deoxyhemoglobin,
greater
Hemoglobin binds and releases at what O2 partial pressure?
- binds to O2 at high PO2
- releases O2 at low PO2
What is hemoglobin affinity?
How quickly & tightly does the hemoglobin bind to O2
When does high affinity hemoglobin become saturated?
at a lower PO2
High affinity is good for what?
Good for loading O2
Low-affinity hemoglobin requires what kind of oxygen partial pressure?
a higher PO2
What is low-affinity hemoglobin good for?
Good for delivering O2
What four factors affect hemoglobin affinity?
pH, CO2, temperature, BPG
What kind of relationship does hemoglobin affinity and pH have?
directly proportional
- increase/increase
- decrease/decrease
In acid conditions (low pH), hemoglobin has what kind of affinity?
low affinity
In acid conditions (low pH), hemoglobin does what to O2?
release O2
In alkaline conditions (high pH), hemoglobin has what kind of affinity?
high affinity
In alkaline conditions (high pH), hemoglobin does what to O2?
will bind to O2
What is the process of altering the hemoglobin/O2 loading/releasing depending on the pH?
Bohr effect
The Bohr effect aids in what?
Aids in the delivery of oxygen to tissues and pick up of oxygen at the lungs
CO2 is 24X more ___________ in plasma than _____.
soluble, O2
What are the three forms CO2 can be transported?
Dissolved CO2 (7%)
Carbaminohemoglobin (23%): bound to Hb
Bicarbonate ion (HCO3 - ) (70%)
What is responsible for controlling breathing?
respiratory centers
Where are respiratory centers located?
Located in the medulla and pons
What are the three respiratory centers?
- Medullary rhythmicity area
- Pneumotaxic area
- Apneustic area
Where is the medullary rhythmicity area located?
Medulla
What is the medullary rhythmicity area’s function?
Controls basic breathing patterns
What kind of neurons does the medullary rhythmicity area contain?
Inspiratory and Expiratory
Inspiratory are responsible for what?
normal breathing (only these used during normal breathing)
Expiratory neurons are active during what?
forceful exhalation (e.g. exercise)
Pneumotaxic area function
increases breathing rate by shortening inhalation to promote exhalation
Impulses shorten inhalation
Pneumotaxic area location
pons
What is responsible for the regulation of respiratory centers?
- Cortical influences
- Chemical Levels of CO2 and H+ affect breathing patterns
- Proprioceptors during movement/exercise signal an increase in breathing
Hering-Breuer reflexes
Apneustic area function
opposite of pneumotaxic,
slows breathing rate activating and prolonging inhalation thus inhibiting exhalation
Apneustic area location
pons
Cortical influences
- too much CO2 causes decrease/acidic pH
- Breathing resumes, regardless of environmental conditions
What structure is responsible for our ability to control our breathing?
Cerebral cortex
The ability to not breathe is dependent upon what?
the buildup of CO2 and H+ in blood
An increase in CO2 or [H+ ] causes what?
stimulation of inspiration
Chemical Levels of CO2 and H+ are sensed by what?
chemoreceptors
What are the two types of chemoreceptors that sense chemical of CO2 and H+?
Central and Peripheral
Central chemoreceptors location
located in medulla
Peripheral chemoreceptors location
aorta and carotid arteries;
Peripheral chemoreceptors are sensitive to what?
these are also sensitive to changes in O2
Chemical Levels of CO2 and H+: what chemical levels increase the breathing rate?
Increased PCO2
decrease in pH,
and/or decrease in PO2
How do proprioceptors affect breathing?
proprioceptors during movement/exercise signal an increase in breathing
Hering-Breuer reflexes
Inflation reflex and exhalation reflex
Inflation reflex
baroreceptors in lungs prevent overfilling
Exhalation reflex
stimulates inhalation center (prevents exhaling too much)
What are the functions of the respiratory system?
- The exchange of gases between the atmosphere, the
blood and the cells - Communication/ speech
- Regulate pH
How does the respiratory system function in the exchange of O2 and CO2?
- To bring in oxygen needed for metabolism
- To rid the body of carbon dioxide
How does the respiratory system help maintain pH?
it keeps the pH slightly above neutral
What structures make up the upper respiratory system?
the nose passages and the pharynx
The nasal passages contain/include what structures?
Nose, nasal cavity, sinuses, hair, and mucus
What is the function of the hair and mucus in the nasal passages?
to trap and filter potentially harmful material from the air
What are the functions of the nasal passages?
- to trap and filter potentially harmful material from the air
- to warm and humidify air entering the nose to keep it at the bodies temperature
- modify sounds used in speech
The nasal passages are the site of what receptors?
olfactory receptors
What is the pharynx?
Common passageway for food and air
How is the pharynx connected to the nasal passages?
by 2 internal nares
Other than the nasal cavity/passage, what other cavity is the pharynx connected to?
oral cavity
What other structures are present in the pharyngeal area?
- Eustachian tubes to ears
- Tonsils and adenoids
What structures make up the lower respiratory tract?
- larynx
- trachea
- bronchi and bronchioles
- lungs
What is the structural function of the larynx?
Connects pharynx to trachea
What is the larynx composed of?
Composed 3 major pieces of cartilage and 3 pairs of smaller cartilage
What are the three pairs of smaller cartilage in the larynx?
- Thyroid cartilage: Adam’s apple
- Cricoid cartilage: below the thyroid cartilage
- Epiglottis: covers larynx during swallowing
The larynx contains what major structure?
Vocal cords: produce sounds used in speech
What is the trachea?
*Tube running from larynx to bronchi
Where is the trachea located?
*Located anterior to the esophagus
What supports the trachea?
*Supported by 15-20 “C” shaped pieces of cartilage
(the rings on the trachea)
What type of tissue lines the trachea?
*Lined by ciliated columnar epithelia
The trachea branches at the bottom to form what structure?
bronchi
What is the function of the bronchi?
*Connects the trachea to alveoli
Bronchi, like the trachea, have what?
*supported by cartilage rings
What are the three different bronchi?
- Primary bronchi (from trachea)
*Secondary bronchi
*Tertiary bronchi
Bronchi branch to form what?
*Bronchioles
*Terminal bronchioles
What are the trends seen in bronchi to terminal bronchioles?
*Pseudostratified ciliated columnar epithelia to simple
cuboidal
*Incomplete cartilage ring to plates to finally disappear
*As cartilage disappears more smooth muscle appears
