Respiratory & Digestive Anatomy

Lumen

a cavity or hole inside of a tube, blood vessel, or hollow organ

ex: blood flows through this of a blood vessel

Acini

a small ball shaped cluster of secretory cells surrounding ducts

Duct

a tubular structure that transports secretions of a gland

compromised of simple cuboidal epithelium arranged in a donut pattern

Lobes

large roundish projections or divisions of an organ

can be seen with the naked eye

Lobules

small divisions of the cells in an organ forming a functional unit

usually require a microscope to be seen

Canal Layers Deep to Superficial

deepest = mucosa, submucosa, muscularis externa, then serosa = superficial

Serosa

a very thin tunic made of simple squamous epithelium that surrounds the outside of the organ

difficult to see bc its so thin but is always present in organs

Muscularis Externa

compromised of at least two layers of the smooth muscle

outer layer has muscle fibers running longitudinally down the organ

next layer runs circularly around the organ

layers help with peristalsis

Submucosa

lays next to the muscularis externa

empty looking tunic in most organs containing only scattered nuclei, a few wavy collagen fibers, and glandular tissue

Mucosa

closest to the lumen

has three sublayers - muscularis mucosa, lamina propria, and epithelium

Muscularis Mucosa

thin layer of smooth muscle thats a distinct as a dark pink band

Lamina Propria

loose matrix of cells and ground tissue

Epithelium

protects the organs from the contents of the lumen

Mediastinum

medial cavity of the thorax containing the heart, great vessels, thymus, and parts of the trachea, bronchi,and esophagus

Visceral Pleura

layer covering the external lung surface and fissures

Parietal Pleura

covers the thoracic wall and superior face of the diaphragm

Visceral Peritoneum

covers the external surface of most digestive organs

Parietal Peritoneum

lines the body walls