BIO 241 HISTOLOGY BIO 241 HISTOLOGY REVIEWREVIEW

Respiratory SystemRespiratory System

Dr. Tim BallardDr. Tim Ballard

Department of Biology and Marine BiologyDepartment of Biology and Marine Biology

TracheaTrachea

Trachea –section – H&E – 4x objective

lumen

ciliated pseudostratified columnar epithelium

submucosa C-shaped ring of hyaline cartilage

esophagus

The arrowhead indicates the trachealis muscle, which bridges the open ends of the C-shaped cartilage ring.

TracheaTrachea

Trachea –section – H&E – 10x objective

lumen

ciliated pseudostratified columnar epithelium

submucosa

hyaline cartilage

adventitia

adipose tissue

Although not shown in this view, goblet cells should be seen easily scattered throughout the epithelial layer.

TracheaTrachea

ciliaTrachea –section – H&E – 40x objective

ciliated pseudostratified columnar epithelium

submucosa

hyaline cartilage

The arrow shows a plate of cartilage, not a C-shaped ring. This is a diagnostic feature of this type of bronchus. Very little smooth muscle is present.

Intrapulmonary bronchusIntrapulmonary bronchus

Intrapulmonary bronchus – cross section – H&E – 10x objective

lumen

ciliated pseudostratified

columnar epithelium

alveoli

The arrow shows a bronchiole. Note that there are no plates of cartilage around it. The arrowhead points out a branch of the pulmonary artery.

BronchioleBronchiole

Bronchiole – cross section – H&E – 4x objective

The star shows a bronchiole. Note that there are no plates of cartilage around it.

BronchioleBronchiole

Bronchiole – cross section – H&E – 10x objective

smooth muscle

Note the change in the epithelium to a short columnar/cuboidal with no goblet cells. Cilia are still present.

BronchioleBronchiole

Bronchiole – cross section – H&E – 40x objective

ciliated simple columnar epithelium

Arrows indicate alveoli arises directly from the respiratory bronchiole. There is simple squamous epithelium and some smooth muscle. PA=pulmonary artery

Respiratory bronchioleRespiratory bronchiole

Respiratory bronchiole – cross section – H&E – 10x objective

respiratory bronchiole

AlveoliAlveoli

Respiratory bronchiole – cross section – H&E – 10x objective

alveolar sac

alveolar wall