Download study guide - Histology on the Fly

Circulatory
System
Heart
•
Function
o Pump blood to the lungs and tissues of the body.
•
Location
o Located in the mediastinum of the thoracic cavity.
•
Structure
o Endocardium
 Simple squamous epithelium
 Thin layer of loose connective tissue
• Elastic and collagen fibers
 Some smooth muscle cells
 Subendocardial layer
• Loose connective tissue
• Veins, nerves and Purkinje fibers (branches of the
conduction system of the heart)
• Connects to myocardium
o Myocardium
 Cardiac muscle cells arranged in spiral layers
o Epicardium (visceral pericardium)
 Simple squamous epithelium (mesothelium)
 Thin layer of loose connective tissue
 Subepicardial layer
• Loose connective tissue
• Coronary vessels, nerves and ganglia
• Fat storage
o Cardiac valves
 Dense fibrous connective tissue
•
Video Recording
o Heart
•
Microscope images
o 4x
o 10x
o 40x
Myocardial Infarct
•
Etiology
o Interruption of blood supply to a portion of the heart
o Cardiac muscle has lack of oxygen and the tissue dies
•
Pathological features
o Acute
 Infiltrative zones of neutrophils
• 10x, 40x
• Necrotic tissue
• Amongst cardiac muscle
o Recent
 Loose connective tissue – granulation tissue
• Inflammation
o Inflammatory cells (i.e. macrophages)
o Remote or healed
 Cardiac muscle replaced with fibrous tissue
• Fibroblasts
• See remnants of cardiac muscle
•
Microscopic images
o 10x
o 40x
Blood Vessels
•
Function
o Transport blood throughout the body.
•
Location
o Most tissues of the body.
•
Structure (Typical)
o Tunica Intima
 Simple squamous epithelium (endothelium)
 Subendothelial layer
• Loose connective tissue
 Internal elastic lamina
• Fenestrated sheet of elastin
o Tunica Media
 Smooth muscle arranged concentrically around the lumen
 External elastic lamina
• Fenestrated sheet of elastin
o Tunica Adventitia
 Fibroelastic connective tissue
•
Structure (Arteries)
o Elastic Arteries
 4x, 10x, 40x
 Tunica Intima
• Endothelium
• Subendothelial layer
• Internal elastic lamina
 Tunica Media
• Many layers of elastic fibers
• Smooth muscle cells
• Thin external elastic lamina
 Tunica Adventitia
• Underdeveloped
o Muscular Arteries
 4x, 10x, 40x
 Tunica Intima
• Thinner than elastic arteries
• Subendothelial layer
• Prominent internal elastic lamina
 Tunica Media

• Many layers of smooth muscle cells
• Thick external elastic lamina
Tunica Adventitia
• Present
o Arterioles
 Tunica Intima
• Thin subendothelial layer
• Internal elastic lamina
o Absent
 Tunica Media
• 2-4 Layers of smooth muscle cells
• External elastic lamina
o Absent
 Tunica Adventitia
• Thin
o Capillaries
 Tunica Intima
• Single layer of endothelial cells
 Tunica Media
• Absent
 Tunica Adventitia
• Absent
•
Structure (Veins)
o Venules and Small Veins
 Tunica Intima
• Single layer of endothelial cells
 Tunica Media
• Absent
 Tunica Adventitia
• Absent
o Medium Veins
 4x, 10x, 40x
 Tunica Intima
• Subendothelial layer
• Valves
 Tunica Media
• Smooth muscle cells loosely organized
 Tunica Adventitia
• Collagen and elastic fibers
• Thickest of all the layers
o Large Veins
 Tunica Intima
• Thick subendothelial layer
• Valves
 Tunica Media
• Thin, few smooth muscle cells
 Tunica Adventitia
• Well developed
•
Video recording
o Muscular artery and medium vein