Histology 14 with supplement Much of this is from Histology 14 Liver Respiration

Pig liver (20X)

Human (20X)

Alternative theory to hepatic systems –Lobule Classical Portal –Acinar (grape-like)

PV – portal venule A – hepatic artery L – lymphatic duct B – bile duct S – sinusoids Limiting plate

Respiratory System Main functions: –Conducts air in/out –Exchange gasses w/blood – respiration –Includes mechanisms to prevent collapse of conducting tubes Bones Cartilage –Two major tube types: 1.Conducting pathway (nasal portion – lungs) 2.Respiration pathway (area of alveolar sacs)

Conducting Pathway Specialized lining of epithelium –“respiratory” epithelium that changes with arborization –Pseudostratified ciliated columnar epithelium With goblet cells – secrete lots of mucus –Cilia beat in one direction: Above pharynx – beat downwards Below pharynx – beat upwards Mucocilary escalator Mucus moved throughout passageway – trap dust

Conducting Pathway (cont.) Blood vessels – warm and moisten air Trachea (main passageway): –Contains C-shaped rings in adventitia R,L primary bronchi (enter lungs) –Same as trachea –Cartilage becomes reduced in bronchi of lungs –Epithelium – begin with pseudostrat ciliated to ciliated columnar Bronchioles –Epithelium – ciliated cuboidal to non-ciliated simple squamous Terminal bronchioles Respiratory bronchioles – start of the respiratory pathway Decrease in cartilage, glands, goblet cells height of epithelium Increase in smooth muscle and elastic tissue Extrapulmonary- Intrapulmonary-

Cells Type I pneumocytes –95% of alveolar surface –Highly flattened –Simple squamous epithelium –Form occluding junctions with one another Barrier to extracellular fluid into alveolus Type II pneumocytes –More numerous; only about 5% of alveolar surface –Cuboidal –Dispersed among type I pneumocytes and form occluding junctions with them –Job: provide surfactant – glycoprotein; reduces surface tension (alveolus won’t collapse) Dust Cell –Small macrophages –Can pass over gas-blood barrier of alveoli

Trachea xs

Trachea ls E – epithelium LP – lamina propria SM – submucosa F – fibroelastic tissue

Primary bronchus E – epithelium LP – lamina propria M – smooth muscle G – seromucous glands C – cartilage Goblet Cells in epith.

Bronchiole V – vein M – sm. Muscle

Terminal portion of respiratory tree –T – terminal bronchiole –R – respiratory bronchiole –V – pulmonary vessel –AD – alveolar duct –AS – alveolar sac –A - alveolus

Drawings of gas exchange

Capillaries Lumen of capillary Endothelial cell Lumen of alveolus Pneumocytes