CV Anatomy Flashcards
Arteries
Carry blood away from the heart to tissues
Gradually decreasing size of vessels (arteries, arterioles, capillaries)
3 layers of arteries
Tunica externa (outer layer) Tunica media (Middle smooth muscular layer) Tunica intima (inner layer) (smooth inner lumem, elastic laminate to maintain shape)
3 types of arteries
Elastic (abdominal aorta) (largest in size, allow for high degree of expansion between heart beats)
Muscular (femoral artery) (distributing arteries, regulate flow of blood to different parts of body)
Arterioles (tributaries) (narrow lumina, thick muscular walls, blood pressure mainly regulated by degree of muscular tone)
Blood pressure is primarily regulated at
Arterioles level
Veins
Carry blood towards heart
Gradually increasing size of vessels (capillaries, venues, veins)
Similar structure to arteries
Walls thinner due to lower blood pressure
Poorly developed muscular layer
3 types of veins
Large (inferior vena cava) (wide bundles of smooth muscle, well developed tunica externa)
Medium (great saphenous vein) (have valves to maintain direction of flow, musculovenous pump)
Small (venules) (unite to form venous plexuses)
Blood flows through arteries and veins
Arteries Arterioles Capillaries Venules Veins
Arteries vs. Veins
Arteries have thick walls (due to smooth muscle in tunica media), veins have thin walls
Arteries have more elastic fibres in tunica media than veins
Arteries smooth muscle is under control of sympathetic nervous system, veins do not have any significant sympathetic innervation
Arteries smallest vessels (arterioles) are surrounded by smooth muscle, venules have no appreciable smooth muscle
Arteries do not have valves, medium vessels contain valves
Capillaries
Simple endothelial tubes
Arranged in networks (capillary beds)
Oxygen, nutrients, carbon dioxide, and other materials exchanged through diffusion
Anatomically similar to tunica intima
Mediastinum
Middle septum occupied by tissue between 2 pulmonary cavities
Covered on each side by mediastinal pleura
Tissues united by loose connective tissue and infiltrated by fat (allows for accommodation to changes in movement, volume, and pressure)
Heart
Slightly larger than clenched fist
Right side receives and sends de-oxygenated blood
Left side receives and sends oxygenated blood
Each side has an atrium and a ventricle
Left is more posterior and right is more anterior
Pericardium
A double walled fibroserous sac enclosing the heart
2 layers
Fibrous pericardium = tough outer layer that stabilizes and prevents over dilation
Serous pericardium = lies within and directly covers heart (can be further divided into visceral/parietal layers)
Visceral and parietal layers of serous pericardium
Between them is the pericardial cavity = a space filled with fluid allowing heart to beat in a frictionless environment
Visceral = on top of organ
Parietal = superficial
3 tissue layers of heart
Epicardium = thin external layer for lubrication Myocardium = thick middle layer for contraction Endocardium = thin internal layer for protection
Walls of heart consist mostly of
Myocardium