respiratory system

functions of respiratory system

gas exchange, pH balance, sound production, olfaction, communication, filter particles from air

What is the process called when oxygen passes from the air into the lungs (alveoli)?

ventilation

What is the process called when oxygen passes from the lungs (alveoli) into the blood (pulmonary capillaries)?

external respiration

What is the process called when oxygen passes from the blood (local capillaries) into the cells?

internal respiration

What is the process called when oxygen is used up inside cells to make ATP?

cellular respiration

During which process does carbon dioxide form inside cells as oxygen is consumed?

cellular respiration

What is the process called when carbon dioxide passes out of cells into the blood (local capillaries)?

Internal respiration

What is the process called when carbon dioxide passes from the blood (pulmonary capillaries) into the lungs (alveoli)?

external respiration

What is the process called when carbon dioxide passes from the lungs (alveoli) back into the air?

ventilation

What are the four levels of gas exchange between oxygen and carbon dioxide?

Ventilation, External Respiration, Internal Respiration, Cellular Respiration

What is the external part of the nose made of?

hyaline cartilage

what are the openings that allow air to enter through the nose called?

External nares (nostrils)

What divides the nasal cavity into right and left halves?

The nasal septum

the nasal septum is made of

ethmoid bone and the vomer

What is the function of the moist, vascular mucous membrane lining the nasal cavities?

To warm and moisten incoming air

What is the function of the nasal conchae?

To circulate, warm, and moisten air

Which bones form the nasal conchae?

Superior and Middle conchae- Part of the ethmoid bone

Inferior conchae- Separate bones

What are the three regions of the pharynx?

Nasopharynx, Oropharynx, and Laryngopharynx

Where is the nasopharynx located?

Posterior to the nasal cavities

What specialized lymphoid tissue is found in the nasopharynx?

pharyngeal tonsil (adenoids)

What important structure opens into the nasopharynx and connects to the middle ear?

The Eustachian (auditory) tube

What is the function of the Eustachian tube?

To equalize air pressure on both sides of the eardrum

Where is the oropharynx located?

Posterior to the oral cavity

What tonsils are found in the oropharynx?

Palatine tonsils and lingual tonsils

What is the function of the tonsils?

Act as lymph nodes to filter incoming air

Where is the laryngopharynx located?

posterior to the larynx

The larynx marks the end of what part of the respiratory tract?

The upper respiratory tract

What is the opening into the larynx called?

The glottis

What structure rests above the glottis and anchors the tongue?

The hyoid bone

What is the function of the epiglottis?

Covers the glottis during swallowing to prevent food from entering the airway

What type of cartilage forms the “Adam’s Apple”?

Thyroid cartilage (hyaline cartilage)

What cartilage forms the back of the larynx?

Cricoid cartilage (hyaline cartilage)

The trachea begins what part of the respiratory tract?

The lower respiratory tract

What lines the trachea to trap particles?

Ciliated mucous membrane

What prevents the trachea from collapsing?

C-shaped rings of hyaline cartilage

What does the trachea branch into?

Two primary bronchi (right and left)

What are the smaller divisions of the bronchi called?

Secondary and tertiary bronchi

What structure do bronchi eventually lead to?

Bronchioles

How do bronchioles differ from bronchi?

They lack cartilage rings and have smooth muscle walls

What are the two types of bronchioles?

Terminal bronchioles and respiratory bronchioles

What do respiratory bronchioles connect to?

Alveoli

What surrounds each alveolus?

Pulmonary capillaries

What occurs at the alveoli during ventilation?

oxygen passes across alveolar membrane into pulmonary capillaries

What do specialized alveolar epithelial cells produce?

Surfactant

What is the function of surfactant?

Reduces surface tension and prevents alveoli from collapsing after exhalation

What stimulates the diaphragm to contract during resting breathing?

Stimulatory signals from the primary respiratory center in the medulla oblongata

What happens when the diaphragm contracts downward?

Lung volume increases, pressure inside lungs decreases, air rushes in.

When does inhalation stop?

When air pressures inside and outside the lungs become equal.

What is the Hering-Breuer reflex?

Stretch receptors in the lungs send inhibitory signals to the medulla when lungs inflate, stopping inspiration.

What happens when the diaphragm relaxes?

Lung volume decreases, pressure inside lungs increases, air rushes out.

What causes exhalation to stop?

When internal and external air pressures become equal.

What restarts the breathing cycle after exhalation?

Stretch receptors stop inhibiting the medulla, medulla sends new signals to diaphragm

What direction do gases like air always move?

From areas of higher pressure to lower pressure.

state Boyle’s Law.

As gas volume increase, pressure decrease

As gas volume decrease, pressure increase

What do the secondary respiratory centers in the pons do?

Modify breathing for voluntary control, deeper or stronger breaths

Which muscles do the pons centers (apneustic center and pneumotaxic center) control?

External intercostal (inhalation) and internal intercostal (exhalation) muscles

What are the two pleural membranes?

Visceral pleura (on lungs) and parietal pleura (lining thoracic cavity)

What separates the pleural membranes?

Serous fluid, allows smooth movement and gentle adhesion.

What muscle forms the floor of the thoracic cavity?

the diaphragm

What membrane covers the lungs?

The visceral pleura

What membrane lines the thoracic cavity?

The parietal pleura.

What is Tidal Volume (TV)?

air breathed in and out in a normal breath.

What is Inspiratory Reserve Volume (IRV)?

volume that can be forced in beyond TV

What is Expiratory Reserve Volume (ERV)?

volume that can be forced out beyond TV.

What is Residual Volume (RV)?

air remaining after maximum expiration.

What is Vital Capacity (VC)?

maximum exhaled after maximum inhale (TV + IRV + ERV)

What is Total Lung Capacity (TLC)?

maximum amount of air the lungs can contain (VC + RV)

What is Dead Space (DS)?

150 mL, air in the respiratory tract not available for gas exchange

What is Forced Vital Capacity (FVC)?

vital capacity exhaled all at once as forcefully as possible.

What is Forced Expiratory Volume 1 (FEV₁)?

percentage of forced vital capacity exhaled in the first second (normally about 80%)

What is Minute Volume?

Breathing rate * tidal volume

What is Alveolar Ventilation Rate (AVR)?

amount of air breathed in one minute of regular breathing available for gas exchange, or that reaches the alveoli

How much oxygen dissolves in plasma?

About 3%.

How much oxygen binds to hemoglobin?

About 97%, forming oxyhemoglobin.

What happens to oxyhemoglobin as it reaches tissues?

It releases oxygen to tissues with the lowest partial pressure of O₂.

What conditions cause more oxygen release from hemoglobin?

Increased temperature and lower pH (more acidic tissues)

What is the formula for bicarbonate formation?

CO₂ + H₂O — H₂CO₃ — H⁺ + HCO₃⁻.

What is the chloride shift?

The exchange of bicarbonate and chloride ions between RBCs and plasma to transport CO2 efficiently and maintain charge balance

When and where does the chloride shift reverse?

In the lungs, bicarbonate re-enters RBCs, converted back to CO2 for exhalation

What happens to CO₂ produced by tissues?

It diffuses into RBCs.

What does CO₂ combine with inside RBCs?

Water (H₂O), forming H2CO3 via carbonic anhydrase

What does carbonic acid (H₂CO₃) break into?

H⁺ and bicarbonate ions

What happens as bicarbonate ions build up in RBCs?

bicarbonate ions flow out into the plasma.

What happens to maintain electrical balance?

chloride⁻ ions move from plasma into RBCs

In what form does most CO₂ travel to the lungs?

As bicarbonate ions, dissolved in plasma

What happens when blood reaches the lungs?

Bicarbonate ions re-enter RBCs

What happens to the CO₂ formed in the lungs?

It diffuses from RBCs into alveoli and is exhaled.

Alveolar ventilation rate formula

Breathing rate * (Tidal volume - dead space)