Week 5 - Respiratory System (Trachea, Branchial Tree, The Lungs and Alveoli)

trachea

tube composed of cartilaginous rings and supporting tissue that connects the lung bronchi and the larynx; provides a route for air to enter and exit the lung

respiratory epithelium

ciliated lining of much of the conducting zone that is specialised to remove debris and pathogens, and produce mucus

bronchial tree

collective name for the multiple branches of the bronchi and bronchioles of the respiratory system

bronchus

tube connected to the trachea that branches into many subsidiaries and provides a passageway for air to enter and leave the lungs

primary bronchi

The first branches of the trachea. There are two primary bronchi, one for each lung.

hilum

concave structure on the mediastinal surface of the lungs where blood vessels, lymphatic vessels, nerves, and a bronchus enter the lung

secondary bronchi

The primary bronchi split into these smaller tubes within the lungs

tertiary bronchi

branches of the secondary bronchi that divide into bronchioles; also called segmental bronchi

terminal bronchiole

branch of bronchi that are 1 mm or less in diameter and terminate at alveolar sacs

respiratory bronchiole

branches of the terminal bronchioles that subdivide into several alveolar ducts

alveous

small, grape-like sac that performs gas exchange in the lungs

lung

organ of the respiratory system that performs gas exchange

lobes

smaller units that compose each lung

fissure

separates lobes in each lung

horizontal fissure

separates the superior and middle lobes of the right lung

right oblique fissure

separates the right middle and inferior lobes

left oblique fissure

separates the superior and inferior lobes of the left lung

pleurae

thin, double-layered serosal membrane that divides thoracic cavity into two pleural compartments and mediastinum

parietal pleura

outermost layer of the pleura that connects to the thoracic wall, mediastinum, and diaphragm

pleural cavity

space between the visceral and parietal pleurae

pleural fluid

substance that acts as a lubricant for the visceral and parietal layers of the pleura during the movement of breathing

visceral pleura

innermost layer of the pleura that is superficial to the lungs and extends into the lung fissures

lingula

a tongue-like extension of the left superior lobe projects anteriorly over the heart

cardiac notch

a concave space on the left lung in which the heart lies

caval foramen

carries the inferior vena cava from the abdomen to the thorax to empty blood into the right atrium of the heart

Oesophageal hiatus

allows the oesophagus to enter the abdomen to empty food into the stomach

aortic hiatus

opening in diaphragm for the aorta to pass from the heart to the abdomen

Type I alveolar cells

simple squamous cells where gas exchange occurs

Type II alveolar cells

secrete surfactant