Chapter 23 lecture- respiratory system

Whats the difference between external and internal respiration

Whats the difference between external and internal respiration

• External- gas exchange between air in lungs and blood in the pulmonary capillaries that surround the alveoli of the lungs

• Internal- gas exchange between the blood in the systemic capillaries and the interstitial fluid/cells that surround them

What are the functions of the respiratory system

• provide an air passageway, gas exchange, olfaction, voice production, regulation of blood pH, protection

What’s the first line of defense in the respiratory system

• The respiratory mucosa

What is the respiratory mucosa

• The respiratory passageway exposed to exterior

• The internal mucus lining acts as a sticky trap to keep stuff away from lungs

  • Mucous and salvia can do this as well

What are alveoli

• Give the lungs a spongy appearence and provide an increase in surface area for gas exchange

What are 3 types of cells in the alveoli and what do they do

• Type 1- 95% of surface and permit gas exchange through simple diffusion

• Type 2- produce surfactant, which reduces surface tension and prevent alveolar collapse and easier for alveoli to expand

• Macrophages

What are the components of the respiratory membrane

• Alveolar epithelium

• Alveolar epithelium basement membrane

• capillary endothelium basement membrane

• capillary endothelium

  • The 2 basement membrane layers fuse

What is pulmonary circulation

• deoxygenated systemic blood that feeds into the pulmonary capillary network and picks up oxygen

• The pulmonary veins being oxygenated blood from lungs back to heart

What is bronchial circulation

• Oxygenated blood to all lung tissue except alveoli

• The bronchial veins carry the deoxygenated blood back to the heart

What is lymph drainage

• IF removal of dust, carbon etc… get filtered by lymph nodes

How is the respiratory system innervated

• Sympathetic NS causes bronchodiolation

• Parasympathetic NS causes bronchoconstriction

What are the pressures associated with ventilation

• Atmospheric

• Intrapulmonary

• Intrapleural

What is the normal atmospheric pressure

• 760 mmHg

Is intrapulmonary or intrapleural pressure higher

• Intrapulmonary

What are the steps of respiration

• Pulmonary ventilation

• alveolar gas exchange

• gas transport

• Systemic gas exchange

What does boyle’s law state

• Volume and pressure are inversely related

How does ventilation occur

• Pressure and volume changes, which create pressure gradients

• Lungs change in volume due to diaphagm and external intercostals

What are two types of breathing

• Quiet breathing and forced breathing

During inspiration what happens to the diaphragm and external intercostals

• The diaphragm flattens and lengthens

• The external intercostals widen

What structures are in the respiratory

• Medulla oblongata and pons

What’s the difference between the medullary respiratory area vs the pontine respiratory center

• Medullary respiratory area connects to the diahragm and intercostal muscles

• Pontine respiratory center is the pons of the brainstem

What are the ventilation cycle steps

• 2 seconds in

  • Signals sent to diaphragm and intercostals → they contact

  • After 2 seconds nuerons become inactive and the muscles relax

• 3 seconds out

What’s a normal ventilation rate

• 12-15 cycles per minute

How does the PNS and CVS regulate respiration

• CNS- Medulla responds to changes in H+ or PCO2 in CSF

• PNS- Aortic arch and carotid arteries response to changes in h+ or PCO2 in the blood

How does a feedback system work with respiration

• When arterial CO2 is high, low pH causes the CNS and PNS to inspire those areas

What is hypocapnia

• Low CO2

what is the Hering Breuer reflex

• Baroreceptor site in bronchi and bronchioles

• Stimulated by an increase in stretch in inhaling

• Prevents excessive inflation in the lungs

how do you find a pressure gradient

• P atm- P alv

How do you find airflow

• P atm- P alv/R

How can resistance be altered

• decreased elasticity of the chest wall and lungs

  • age and diseases can cause this

• Change in diameter of airways

• Collapse of alveoli

  • increased surface tension

What does bronchoconstriction and bronchodilation do in the airpassageways

• Bronchoconstriction increases releases and slows down airflow from the parasympathetic nervous system

• Bronchodilation decreases resistance and speeds up airflow from the sympathetic nervous system

What is lung and throax compliance

• How easy it is for lungs and thorax to expand and recoil

  • low compliance=hard to expand

  • High compliance=east to expand

What is lung recoil

• The tendency of the lungs to decrease in size after inhaling

• The diaphragm moves up and decreases the amount of plueral space, the elasticity of lungs and cohesion of water molecules force lung size to go back to normal

What happens to energy as resistance increases

• energy increases because our inspirations are more forceful

What is the glottis

• The opening to the larynx

What is valsalva maneuver

• Trying to exhale when holding your breath and the glottis is closed

• This increases pressure and lowers VR and may cause fainting

How do you find pulmonary ventilation rate

• ventilation rate * tidal volume

What % of air reaches the alveoli and what happens to rest

• 70% for the alveoli

• 30% goes to the conducting zone

How much of the atmosphere is oxygen

• 20.9% or 159 mmHg

What changes do you see in the atmosphere air vs exhaled air

• The amount of nitrogen and oxygen decrease

• Water and CO2 increase

Does gas exchange increase or decrease if the respiratory membrane thickens

• Reduces

What is Henry’s law

• The amount of gas that can move into a liquid is equal to its partial pressure and solubility in the liquid

With gas transport how much oxygen stays in the plasma

• 2%

What happens to 98% of oxygen during gas transport

• Moves to erythrocytes and binds to hemoglobin

With gas transport how much carbon stays in the plasma

• 7%

How much of the carbon during gas transport binds to hemoglobin creating HbCO2

• 23%

What does 70% percent of CO2 do during gas transport

• Converts to H2CO3 and then to HCO3 and then into the plasma as HCO3-

Is pH lower in veins or arteries and why

• Veins

  • because it is transporting CO2

Does a decrease in pH lead to hypoventilation or hyperventilation

• Hyperventilation

How do you find the a-v O2 difference

• Arterial saturation (98%)- venous saturation

After oxygen dissociates where does it go and why

• To tissues so cell resp. can occur

During exercise does oxygen reserve increase or decrease

• Decrease

What mechanisms enhance the release of O2 to active tissues

• Active tissues produce more heat, lower pH, promotes oxygen unloading to tissue and carbon binding to Hb