Cardiovascular Flashcards
pumps and directs blood cells and substances carried in blood to all tissues of the body
Circulatory System
organ that serves as a pump to circulate the blood
Heart
three main layers of the heart
Epicardium
Myocardium
Endocardium
Consists of a very thin inner layer of
endothelium and supporting connective
tissue, a middle myoelastic layer of smooth
muscle fibers and connective tissue
Endocardium
Consists mainly of cardiac muscle with its
fibers arranged spirally around each heart
chamber ; Thicker in the walls of the ventricles, particularly the left, than in the atrial walls
Myocardium
A simple squamous mesothelium supported by a layer of loose connective tissue containing blood vessels and nerves ; Corresponds to the visceral layer of the
pericardium
Epicardium
Dense irregular fibrous connective tissue ; Forms part of the interventricular and
interatrial septa surrounds all valves of the heart, and extends into the valve cusps and the chordae tendineae to which they are
attached
Cardiac skeleton
divides the atrium and
ventricles
Septa
Generates and propagates waves of
depolarization that spread through the
myocardium to stimulate rhythmic
contractions
Conducting system of the heart
Conducting system of the heart
Sinoatrial (SA) node (or pacemaker) and the
atrioventricular (AV) node AV bundle (of
His) subendocardial conducting network
Composed of connective tissue with overlying endocardium
Heart valves
3 layers of the heart valve
Fibrosa
Spongiosa
Ventricularis
core of the valve and contains
fibrous extensions from the dense irregular
connective tissue of the skeletal rings of the
heart
Fibrosa
loose connective tissue located
on the atrial or blood vessel side of each valve ; acts as a shock absorber to dampen
vibrations associated with the closing of the valve
Spongiosa
adjacent to the ventricular or
atrial surface of each valve and is covered
with endothelium ;
Ventricularis
Tissues of the Vascular Wall
Endothelium
Smooth muscle
Connective tissue
specialized epithelium that acts as a
semipermeable barrier between two major
internal compartments: the blood plasma and the interstitial tissue fluid
Endothelium
Vascular endothelial cells are squamous,
polygonal, and elongated with the long axis in the direction of blood flow
Endothelium
agents that control local clot formation
heparin
tissue plasminogen activator
von Willebrand factor
Layers of Vascular Wall
Tunica intima
Tunica media
Tunica adventitia
The innermost layer of the vessel
Tunica intima
Consists primarily of circumferentially
arranged layers of smooth muscle cells
Tunica media
Composed primarily of longitudinally arranged collagenous tissue (type I) and a few elastic fibers ; Contains the vasa vasorum and nervi vascularis
Tunica adventitia
the blood supply of the blood
vessel
Vasa vasorum
the nerve supply of the blood
vessels
Nervi vascularis
Distribute blood to the organs and help
regulate blood pressure by contracting or
relaxing the smooth muscle in the media
Muscular arteries
called conducting arteries because their
major role is to carry blood to smaller arteries
Elastic arteries
Smallest arteries branch ; Indicate the beginning of an organ’s microvasculature
Arterioles
Form blood vascular networks that allow fluids containing gases, metabolites, and waste products to move through their thin walls
Capillaries
Capillaries always function in groups called
capillary beds
3 types of capillaries
Continuous capillaries
Fenestrated capillaries
Sinusoidal capillaries
Distinct continuity of the endothelial cells in its wall ; Most common type of capillary ; Found in all kinds of muscle tissue, connective tissue, exocrine glands, and nervous tissue
Continuous capillaries
Characterized by the presence of small
circular fenestrae through the very thin
squamous endothelial cells ; Each fenestra is usually covered by a very thin
diaphragm
Fenestrated capillaries
Endothelial cells have large fenestrae without
diaphragms ; the cells form a discontinuous
layer and are separated from one another by
wide spaces ; the basal lamina is also
discontinuous
Sinusoidal capillaries
Collect blood from the capillary network ; Characterized by the presence of pericytes
Post capillary Venules
pericytescells of mesenchymal origin with long
cytoplasmic processes partly surrounding the
endothelial layer
pericytes
provide vascular support and promote
stability of capillaries and postcapillary
venules
pericytes
Diameter of as much as 10mm ; Valves are a characteristic feature of these
vessels ; Most numerous in the inferior portion of the body, particularly the lower limb
Medium Veins
Diameter greater than 10mm ; Tunica adventitia of large veins (subclavian
veins, portal vein, and the venae cava) is the
thickest layer of the vessel wall ; Tunica adventitia also contains longitudinally
disposed smooth muscle cells
Large Veins
Direct routes between the arteries and veins
that divert blood from the capillaries
Arteriovenous shunts
Found in the skin of the fingertips, nose, and
lips and in the erectile tissue of the penis and
clitoris
Arteriovenous shunts
Atypical Blood Vessels
Coronary arteries
Dural venous sinuses
Great saphenous vein
Central adrenomedullary vein
Considered to be a medium-sized muscular
arteries ; Blood vessels that supplies nutrients and oxygen to the blood
Coronary arteries
Originate from the proximal part of the
ascending aorta and lie on the surface of the
heart in the epicardium surrounded by
adipose tissue
Coronary arteries
Venous channels in the cranial cavity ; Broad spaces within the dura mater that are
lined with endothelial cells and devoid of
smooth muscles ; also the blood supply to cranial activity
Dural venous sinuses
A long subcutaneous vein of the lower limb
that originates in the foot drains into the
femoral vein just below the inguinal ligament
Great saphenous vein
Possesses numerous longitudinal smooth
muscle bundles in the intima and in the well-developed adventitia
Great saphenous vein
Passes through the adrenal medulla and its
tributaries have an unusual tunica media ; Contains several longitudinally oriented
bundles of smooth muscle cells that vary in
size and appearance (MUSCLE CUSHIONS)
Central adrenomedullary vein
have more numerous internal valves than veins ; often dilated with lymph ; ultimately converge as two large trunks
Lymphatic Vessels
Excess interstitial fluid
Lymph
Originate as closed-ended vessels consisting
of a single layer of very thin endothelial cells on an incomplete basal lamina
Lymphatic capillaries (or lymphatics)
Resembles that of veins except with thinner
walls and no distinct separation among tunics
Lymphatic vessels
