Respiratory System

What is the chemical equation for cellular respiration?

C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP

Difference between external and internal respiration?

External respiration encompasses the steps involved in the exchange of O2 and CO2 between the external environment and tissue cells

Cellular respiration encompasses the intracellular metabolic reactions involving the use of O2 to derive energy (ATP) from food, producing CO2 as a by-product

Why is it necessary to eliminate CO2?

To maintain acid-base balance in the body and prevent respiratory acidosis

How does the respiratory system assist in blood pressure regulation?

It helps in the synthesis of Angiotensin II.

What are the 8 functions of the respiratory system?

2. Gas exchange

3. Communication

4. Olfaction

5. Acid-base balance

6. BP regulation (Angiotensin II)

7. Blood and lymph flow (pressure gradients)

8. Blood filtration (dissolve small blood clots)

9. Expulsion of abdominal contents (breath-holding during childbirth, defecation, and urination)

The respiratory airways include?

The nasal passages

Pharynx

Larynx

Trachea

Bronchi

Bronchioles

What is clustered in grapelike arrangements at the end of terminal bronchioles?

Alveoli

What is the functional difference between the conducting division and the respiratory division?

Conducting division: responsible for airflow and does not participate in gas exchange

Respiratory division: involves structures like alveoli where actual gas exchange occurs

What are the three primary functions of the nose?

1. Detects odors (olfactory nerves)

2. Warms, cleanses, and humidifies inhaled hair

3. Serves as a resonating chamber that amplifies voice

Where is the respiratory erectile tissue (swell body) located?

In the epithelium of the inferior concha.

Every 30-60 minutes, tissues on one side of the nose?

Swells with blood so most air is directed through the other nostril

How often does the preponderant flow of air shift between the right and left nostrils?

Once or twice every hour (every 30 to 60 minutes).

What is the physiological purpose of the alternating swell body in the nasal cavity?

It restricts airflow through one fossa to allow the engorged side time to recover from drying.

What are the three distinct regions of the pharynx?

Nasopharynx, oropharynx, and laryngopharynx.

What structure is commonly referred to as the 'voicebox'?

The larynx.

What is the function of the epiglottis?

It guards the superior opening of the larynx to prevent food from entering the airway.

What is the anatomical definition of the glottis?

The opening or hole between the vocal cords.

How is a high-pitched vocalization produced by the vocal cords? How is a low-pitched vocalization produced by the vocal cords?

The vocal cords are pulled tight by muscles associated with the larynx to produce high pitched vocals

The vocal cords are loosened by the relaxation of muscles associated with the larynx to produce low pitched vocals

What type of cartilage makes up the tracheal rings (trachea)? What shape is it?

Hyaline cartilage, C-shaped

What is the function of the trachealis muscle?

It bridges the gap in the C-shaped tracheal rings and allows the trachea to adjust its diameter.

What specific tissue type lines the conducting airways of the respiratory tract?

Ciliated pseudostratified epithelium.

What is the role of goblet cells in the respiratory epithelium?

They secrete mucus to trap inhaled particles and debris.

What cellular change, known as metaplasia, occurs in the respiratory tract after approximately 30 days of smoking?

Ciliated epithelium transforms into squamous epithelium, reducing mucus clearance and increasing infection risk

Which cells in the alveoli are responsible for producing surfactant?

Type II alveolar cells.

Which cells forms the alveolar walls?

Type I alveolar cells

What is the primary function of pulmonary surfactant?

It reduces surface tension to prevent the alveoli from collapsing during expiration.

Which alveolar cells are extremely thin to facilitate rapid gas exchange?

Type I alveolar cells.

What is the function of alveolar macrophages (dust cells)?

Part of non-specific immune system that phagocytizes dust particles and debris may have been inhaled

Visceral pleura vs Parietal pleura

Visceral: Inner membrane attached to lung tissue

Parietal: Outer membrane attached to thoracic wall tissue

What is the space between the visceral and parietal pleurae called?

The pleural cavity.

Which nerve innervates the diaphragm and is essential for breathing?

The phrenic nerve.

Accessory muscles of inspiration contract when?

During forced inhalation to assist breathing

Muscles of active expiration contract when?

During forced exhalation to assist breathing

Major muscles of inspiration contract when?

During normal and deep inhalation to increase lung volume

What makes up the accessory muscles of inspiration?

Sternocleidomastoid

Scalenus

What makes up the muscles of active expiration?

Abdominal muscles

Internal intercostal muscles

What makes up the major muscles of inspiration?

Diaphragm

External intercostal muscles

Diaphragm contracts and relaxes when?

Contracts during inhalation and relaxes during exhalation

Which spinal nerve roots contribute to the phrenic nerve?

C3-C5

Internal vs external intercostal muscles?

Intercostal: exhaling, thoracic cavity smaller

• thoracic cavity decreases in size

• Ribs flatten

External: inhale

• thoracic cavity increases in size

• Ribs increase horizontally

What are the primary muscle actions during inspiration?

The diaphragm contracts and flattens while the external intercostal muscles contract to elevate the ribs.

If the phrenic nerve is damaged, what happens?

The diaphragm may become paralyzed, leading to impaired ability to breathe and potential respiratory distress

What was the mechanical purpose of an 'iron lung' used during the polio epidemic?

It served as a negative pressure ventilator, expanding the chest cavity to draw air in by vacuum and release, at certain # breaths/min

Modern medical devices for ventilation work how?

They use a breathing tube and positive pressure to blow air or a mixture of other gases (like oxygen and air) into lungs at a certain volume for a set # breaths/min

What is intrapleural fluid?

A lubricating fluid found in the pleural cavity that facilitates the movement of the lungs and prevents friction during breathing

In a healthy individual at rest, how does intrapleural pressure compare to atmospheric pressure?

Intrapleural pressure is usually less than atmospheric pressure

Atmospheric pressure

The pressure exerted by the weight of the gas in the atmosphere on objects on Earth’s surface

• 760 mmHg @ sea vele

Intra-alveolar pressure

The pressure within the alveoli that is involved in the process of gas exchange

Intrapleural pressure

The pressure within the pleural cavity that is always less than intra-alveolar pressure, creating an environment that allows for lung expansion

• 756 mmHg

How does intra-alveolar pressure relate to atmospheric pressure when the airways are open and no air is moving?

They are equilibrated and equal (both at 760 mmHg at sea level).

In terms of airway physics, what is the result of bronchoconstriction?

Airway radius decreases

Resistance increases

Airflow decreases

Transmural pressure gradient across lung wall

Intra-alveolar pressure - intrapleural pressure

Transmural pressure gradient across thoracic wall

Atmospheric pressure - intrapleural pressure

What happens when the transmural pressure gradient is abolished across the thoracic wall?

Lungs collapse due to its unstretched size and the chest wall springs outward

What happens when the transmural pressure gradient is abolished across the lung wall?

The lung collapses due to loss of volume

What happens in traumatic pneumothorax?

A puncture in the chest wall permits air from the atmosphere to flow down its pressure gradient and enter the pleural cavity, abolishing the transmural pressure gradient

What happens in spontaneous pneumothorax?

A hole in the lung wall permits air to move down its pressure gradient and enter the pleural cavity from the lungs, abolishing the transmural pressure gradient.

What is Boyles law?

P1V1 = P2V2

• volume of a gas increases the pressure of the gas decreases proportionately - vise versa

Atelectasis

Atelectasis refers to the collapse or partial collapse of a lung or a lobe of the lung

Lung Compliance

The willingness or ease with which the alveoli stretch and expand.

Which division of the respiratory system contains the respiratory bronchioles and alveolar sacs?

The respiratory division

The process by which oxygen moves from the blood into tissue cells is called _.

Systemic gas exchange.

The ridge of cartilage at the base of the trachea that directs airflow to the left and right lungs is the _.

Carina.

Air flows from?

High pressure to low pressure

What characteristics show when inspiration?

• Diaphragm contracts and moves downward

• Rib cage expands

• Thoracic cavity volume increases

• Lungs expand

What characteristics show when expiration?

• Diaphragm relaxes

• Rib cage moves back down

• Lungs recoil to original size

• Thoracic volume decreases

When pressure increases, which is higher intra-alveolar or atmospheric pressure?

Intra-alveolar pressure is higher

Airway radius decreasing =

Bronchoconstriction

• Increased resistance

• Decreased airflow

Airway radius increasing =

Bronchodilation

• Decreased resistance

• Increased airflow