Respiratory System

What are the major functions of the respiratory system?

Speech and sound production

Olfaction (smell)

Thoracic cavity pressure changes (urination, childbirth, venous blood)

Homeostasis (blood pH)

What are the four respiratory processes?

Pulmonary ventilation, pulmonary gas exchange, gas transport in blood, and tissue gas exchange

What is the conducting zone?

The part of the respiratory tract that air travels through

What is the respiratory zone?

The area where gas exchange occurs

What are the functions of the nose and nasal cavity?

Warms and humidifies air, filters debris, and provides sound resonance.

What are the nasal meatuses?

Spaces between the nasal conchae that increase surface area and turbulence and help filter/extract debris and dust and allow for more mucus pickup

What is the function of the sinuses?

They connect to the nasal cavity and allow movement of air and mucus; they warm, humidify, and filter air and provide voice resonance.

Where is the olfactory mucosa located?

In the roof of the nasal cavity

What do olfactory receptors do?

They are located in the olfactory mucosa

What do goblet cells do?

Secrete mucus that trap particles

What does cilia do in the respiratory tract?

Propels mucus and debris towards the posterior nasal cavity

What does the lamina propria contain?

Blood vessels

What does lymphatic tissue do?

Traps pathogens

What are the three regions of the pharynx?

Nasopharynx, oropharynx, laryngopharynx

What is the function of the nasopharynx

Warms, humidifies, and filters air

What is the function of the oropharynx and laryngopharynx?

Passageway for food and air

What does the pharyngotympanic tube connect?

The middle ear to the nasopharynx

What is the function of the pharyngotympanic tube?

Equalizes pressure and aids sound transmission

What is the function of the larynx?

Keeps food and liquids out of the respiratory tract

Supports sound production and structure

What do cilia in the larynx do?

Propel mucus and debris upward

What is the epiglottis?

Flap of elastic cartilage that covers the glottic during swallowing

What does the epiglottis prevent?

Food and liquids from entering the lower respiratory tract

What are the vestibular folds?

False vocal cords

Folds that tighten during swallowing to close of the glottis

What are vocal folds?

True vocal cords

Vocal cords containing elastic bands that vibrate to produce sound when air passes over them

What determines the pitch of the voice?

Muscle control of vocal cord length and tension

What happens to vocal cords for a high pitch?

They become longer and thinner

Rotate inward

Narrow the glottis and vibrate

What happens to vocal cords for a low pitch?

They become shorter and thicker

Rotate outward

Expand the glottis and vibrate

What is the function of the trachea?

Delivers air to the lower respiratory tract

What tracheal cells trap and move debris?

Goblet cells and cilia

What type of tissue gives the trachea flexibility?

Elastic tissue

What supports the trachea and keeps it open?

C shaped cartilage rings

Why are cartilage rings absent from the posterior tracheal surface?

Allow the esophagus to expand

What is the carina?

The last cartilage ring of the trachea

What happens when sensory receptors at the carina are stimulated?

They trigger a violent cough reflex

How does the right primary bronchi compare with the left?

Right is wider, shorter, straighter

Left is narrower, longer, horizontal

How many secondary bronchi are on each side

Right-3

Left-2

(One per lobe of the lung)

What are bronchioles?

Smallest airways

What distinguishes bronchioles from bronchi?

Bronchioles lack cartilage and have thick rings of smooth muscle

What is the last part of the conducting zone?

Terminal bronchioles

What begins the respiratory zone?

Respiratory bronchioles

What do respiratory bronchioles branch into?

Alveolar duct→ alveolar sacs→alveioli

What are type I alveolar cells?

Make up most of alveolar cells

Thin, allowing for rapid gas diffusion

What are type II alveolar cells?

Make up about 10%

Thick and not involved in gas exchange

What do type II alveolar cells contain?

Precursor to surfactant

What cells clean up debris inside alveoli?

Alveolar macrophages

What happens to alveolar macrophages after collecting debris?

They migrate up the bronchiole chain and are eventually swallowed or coughed out

What is the respiratory membrane?

The barrier across which gases diffuse

What are the three components of the respiratory membrane?

Type I alveolar cells, basal lamina, and capillary endothelial cells

Why is the respiratory membrane thin?

To allow efficient gas exchange

What are pleurae?

Layered membranes covering each lung

What is the function of pleurae?

Maintain pressure that prevents lung collapse

What is the parietal pleurae?

The pleura fused to surrounding structures such as the rib cage and diaphragm

What is the pleural fluid?

Serous fluid lubricates the lungs and reduces friction

What else does pleural fluid help with?

It helps the visceral pleura adhere to the parietal pleura

What does the visceral pleura cover?

The lung surface and fissures

What is pulmonary ventilation?

Air moving into and out of the lungs

What is inspiration?

Air moving into the lungs

Pressure decreases, volume increases

What is expiration?

Air moving out of the lungs

Pressure increases, volume decreases

What is external respiration?

Gas exchange between the blood and lungs

What is gas transport?

Transport of gases in the blood

What is internal respiration?

Gas exchange between blood and tissue cells

How are pressure and volume related?

They are inversely related

When one is increases the other is decreased

What happens to gas pressure when volume increases?

Gas pressure decreases

What happens to gas pressure when volume decreases?

Gas pressure increases

What is atmospheric pressure?

Pressure exerted by the pull of gravity on air

How does atmospheric pressure change with elevation?

It increases at lower elevations and decreases at higher elevations

What is intrapulmonary pressure?

Pressure within the alveoli

How does intrapulmonary pressure change during inspiration?

It decreases

How does intrapulmonary pressure change during expiration?

It increases

What does intrapulmonary pressure equal between breaths?

Atmospheric pressure

What is intrapleural pressure?

Pressure within the pleural cavity

How does intrapleural pressure change during inspiration?

It decreases

does intrapleural pressure change during expiration?

It increases

Does intrapleural pressure equal atmospheric pressure?

No, it reamains lower than intrapulmonary pressure

What muscles contract during inspiration

The diaphragm and intercostal muscles

What happens during inspiration?

Thoracic/lung volume increases, intrapulmonary pressure decreases, and air flows in

What happens during expiration?

Muscles relax, elastic recoil decreases volume, pressure increases, and air flows out

What is airway resistance?

Resistance to airflow through the respiratory tract

How does airway diameter affect resistance?

Diameter changes affect resistance to airflow

What is bronchodilation?

An increase in airway diameter

What is bronchoconstriction?

A decrease in airway diameter

What causes airway diameter to vary during ventilation?

Changes in intrapulmonary pressure

What is alveolar surface tension?

Attraction between water molecules at the gas/water boundary

What can increases alveolar surface tension cause?

Alveoli to collapse

What does surfactant do?

Reduces surface tension by disrupting bonds between water molecules

Why is surfactant important during expiration?

It allows alveoli to stay open during expiration

What is pulmonary compliance?

The ability of the lungs and chest wall to stretch

What three factors affect pulmonary compliance?

Alveolar surface tension

Elastic tissue distensibility (stretch)

Chest wall stretch

How does increased surface tension affect compliance?

Increased surface tension decreases compliance

What is partial pressue?

The pressure exerted by an individual gas in a mixture

What determines how much gas dissolves in a liquid?

The gas’s partial pressure and its solubility

How does CO2 compare with O2 in water solubility?

CO2 has greater solubility in water

Which direction does O2 move during pulmonary gas exchange?

Alveoli→erythrocytes

Which direction does CO2 move during pulmonary gas exchange?

Plasma and erythrocytes→alveoli

What happens when respiratory membrane surface area increases?

Gas exchange efficiency increases

What happens when respiratory membrane thickness increases

Diffusion decreases

What is ventilation-perfusion matching?

The relationship between alveolar air and pulmonary capillary blood flow

What happens to pulmonary arterioles with low alveolar PO2?

They constrict

Blood vessels narrow in area with low oxygen to allow blood oxygen levels to stay high

What happens to bronchioles with increased PCO2?

They constrict

Bronchiole will keep as much CO2 as it can

How is most O2 transported in blood?

Bound to Hb