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)
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PV – portal venule
A – hepatic artery
L – lymphatic duct
B – bile duct
S – sinusoids
Limiting plate
Respiratory System
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Main functions:
– Conducts air in/out
– Exchange gasses w/blood – respiration
– Includes mechanisms to prevent collapse of
conducting tubes
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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)
• Extrapulmonary• Intrapulmonary-
– 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
Cells
• Type I pneumocytes
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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
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E – epithelium
LP – lamina propria
SM – submucosa
F – fibroelastic tissue
Primary bronchus
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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
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T – terminal bronchiole
R – respiratory bronchiole
V – pulmonary vessel
AD – alveolar duct
AS – alveolar sac
A - alveolus
Drawings of gas exchange
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Capillaries
Lumen of capillary
Endothelial cell
Lumen of alveolus
Pneumocytes