Respiratory Zone, Alveoli, respiratory membrane, and Lungs (slides 18-24)

What is the sequence of the respiratory zone?

• Respiratory Bronchioles

• Alveolar Ducts

• Alveolar Sacs

• Alveoli

Each alveolus is surrounded by a?

Capillary bed

Pulmonary arteries bring what to the alveoli?

Deoxygenated blood

Pulmonary veins bring out of the alveoli?

Oxygenated Blood

What are common chambers connected to many individual Alveoli?

Alveolar sacs

Each lung contains how many alveoli?

~300-400 million alveoli

• more alveoli means more surface area for gas exchange

What structure in the alveoli helps with the recoiling and expansion of it?

• smooth muscle

• Elastic bands/fibers

What are the three major cell types in the alveolar epithelium?

• Type I alveolar cells

• Type Il alveolar cells

• Alveolar macrophages

What is the function of alveoli?

Transfers inhaled oxygen into the bloodstream and remove carbon dioxide from the blood to be exhaled

What alveolar cell is being described:

• Thin

• Delicate cells

• site of gas exchange

Type 1 alveolar cells

What alveolar cell is being described:

• Septal cells

• Produces surfactant (very slippery)

  • which reduces surface tension to prevent them from sticking together, preventing collapse

Type 2 alveolar cells

What alveolar cell is being described:

• Dust Cells

• Removes Debris

• Are known to be “fixed” because they only live in the lungs

Alveolar Macrophages

What is the respiratory membrane?

It’s the ultra‑thin barrier between:

• the air inside an alveolus
  and

• the blood inside a pulmonary capillary.

• Where gas exchange occurs

• ~0.5 micrometer thick

• Only consists of type 1 alveolar cell

What are the four layers of the respiratory membrane that oxygen, carbon dioxide, and other nutrients and waste must pass through during gas exchange?

• Capillary endothelium

• Capillary basement membrane

• Alveolar epithelial basement membrane

• Alveolar epithelium of type 1 alveolar cells

What two respiratory membranes are fused togther?

• Capillary basement membrane

• Alveolar epithelial basement membrane

What is a paired organ in the thoracic cavity?

Lungs

The thoracic cavity is divided by?

• Two pleural cavities

• Mediastinum in the middle

The lungs are within, enclosed, and protected by?

Right and left pleural cavities/membranes

How many layers does the pleural cavities/membranes have?

Three

• Parietal Pleura

• Visceral Pleura

• Pleural Cavity

The pleural cavity is full of?

Serous Fluid

• 15mm

• drained by lymphatic system

What two pleural membranes/cavities are always in contact with one another because if not, it will collapse?

• Parietal Pleura

• Visceral Pleura

If air comes in between the two layers → lungs collapse

The Parietal Pleura is attached to the wall of the?

Pleural Cavity

The Visceral Pleura is tightly attached to the?

Surface area of the lung

Serous membrane is a general term for?

A double‑layered membrane that lines body cavities and covers organs, producing a thin, watery serous fluid to reduce friction.

If we inhale, our chest?

Expands

• The parietal pleura moves outward with it because it is physically attached to the chest wall

• The visceral pleura and lungs follow because the pleural fluid prevents the two layers from separating.

Where does the primary bronchus enter the lungs? (along with arteries and veins)

Hilum/Hilus

What is the root of the lung?

Hilum and the contents passing through it (primary bronchus, arteries, veins, etc)

Which lung is bigger right or left?

Right

How many lobes are on the right lung?

three

• Superior

• Middle

• Inferior

How many lobes are on the left lung?

Two

• Superior

• Inferior

What fissures are on the right lung?

• Oblique

• Horizontal

What fissures are on the left lung?

• Oblique

Which lung has a specific feature to make space for the heart, what is the feature called?

Left lung

• Cardiac Notch

How many bronchopulmonary segments are on each lung?

~ 10 each side

Each bronchopulmonary segment is supplied by?

Segmental (tertiary) Bronchus

What are the two blood circulations the lungs are involved with?

• Systemic

• Pulmonary

What circulation is being described:

• Consists of pulmonary arteries and vein

• Take deoxygenated blood to the lungs to be oxygenated

• Right ventricle → pulmonary trunk → pulmonary arteries → lungs → pulmonary capillaries → pulmonary veins → left atrium

Pulmonary circulation

What circulation is being described:

• Consists of bronchial arteries and vein

• Take oxygenated blood to the rest of the body

• Left ventricle → aorta → systemic arteries → capillaries → systemic veins → vena cavae → right atrium

Systemic circulation

What is an autonomous unit, encapsulated within CT, and supplied with a segmental bronchus, pulmonary artery, pulmonary vein, and lymph vessels?

Bronchopulmonary segment