Circulatory system Flashcards
large blood vessels all have 3 common layers
tunica intima, tunica media, and tunica adventitia
large vessels have other smaller vessels called _ that branch through adventitia
vasa vasorum
what has more vasa vasorum
veins
larger vessels may have lymphatic vessels and nerves called _ in adventitia
nervi vascularis
described as endothelium and underlying subendothelial connective tissue; has internal elastic lamina too
tunica intima
described as primarily smooth muscle cells and also external elastic lamina
tunica media
described as fibroelastic connective tissue (dense irregular CT with small amounts of elastic fibers)
tunica adventitia
arteries are classified as large _, medium _, and small _
elastic
muscular
arterioles
what type of artery conducts blood to muscular arteries
elastic (conducting) artery
elastic fibers of intima from an
incomplete internal elastic lamina
elastic arteries have _ media and _ adventitia while no distinct _ and an incomplete _
thick
thin
external elastic lamina
internal elastic lamina
what type of artery delivers blood to organs
muscular (distributing)
muscular arteries have a _ intima with _
thin
well-developed internal elastic lamina
muscular arteries have a _ external elastic lamina
thick
how many layers of endothelial cells are capillaries
one
capillaries are surrounded by a thin sheath of reticular and collagenous fibers and some _, which are
pericytes
mesenchymal-like stem cells (can become fibroblasts or smooth muscle cells)
what type of capillary has continuous endothelium and basal lamina
continuous
continuous capillaries have _
no fenestrae
continuous capillaries are found
in muscle, connective tissue, CNS, exocrine pancreas, and gonads
in the CNS, continuous capillaries have a type of _ that contributes to _
tight junction
blood-brain barrier
fenestrated capillaries are located in the
mucosa of GI tract, endocrine glands, renal glomerular and peritubular capillaries, choroid plexus, and ciliary body
fenestrated endothelium in the glomerular capillaries have _
no diaphgrams
discontinuous (sinusoidal) capillaries are found in
liver and hemopoeietic organs such as bone marrow and spleen (know all of these)
discontinuous capillaries have _ basal lamina and wide gaps between cells
incomplete
what receives blood from capillaries
postcapillary venules
postcapillary venules have an _ layer of pericytes
incomplete
postcapillary venules are an important site of
activity in inflammation
veins start as
venules
vein intima consists of
endothelial cells
vein media consists of
1-2 layers of smooth muscle
what type of venule has 1-2 layers of smooth muscle and thin adventitia; no pericytes
muscular venules
intima of small to medium size veins are how big
1-9 mm diameter
intima of small to medium size veins consists of
thin subendothelial connective tissue layer
superior and inferior vena cava and portal trunk are examples of
large veins
large veins have _ with
thick adventitia (collagenous fibers and longitudinal arranged smooth muscle cells)
venous valves prevent _ blood flow; valves are usually in _ to _ size veins; valves are paired _ folds of the intima covered with endothelium
retrograde
small to medium
semilunar folds
arteriovenous anastomoses have a specialized tunica media with a sphincter; when this shunt is closed what happens
arterial blood flows into the capillary bed
when the arteriovenous anastomoses shunt is opened what happens
blood bypasses the capillary bed and flows into a vein
some microvascular beds have a _ sphincter, which controls the amount of blood flowing into the capillary
precapillary
_ in the intestine are an important route of fat absorption
lacteals
lacteals are an _ lined vessel; lymph only flows in one direction; towards the base of the neck
endothelial
lympathic vessels originate in connective tissue as
anastomosing capillaries
lymphatic capillaries have no
basal lamina
CNS and bone have no
lymphatic system
lympathic vessels can be held open by
fine anchoring filaments attached to perivascular collagen
skeletal muscle has lymphatics only in
perimysium
foam cell (lipid laden macrophage) formation and fatty deposits in intima may block vessel
atherosclerosis
smooth muscle cell proliferation that follows angioplasty procedure; may occlude vessel
restenosis
ballooning out of artery causing weakness in the arterial wall
aneurysm
tortuous, dilated veins, primarily in legs of older persons; caused by decrease in muscle tone and failure of venous valves
varicose veins
atheroma formation eventually leads to
calcification
endothelial cells play a
regulatory role
endothelial cells produce _ from arachidonic acid; what does this product do
prostacyclin that inhibits platelet adhesion and clot formation
endothelial cells secrete _ that causes smooth muscle in the t. media to relax = vasodilation
nitric oxide
endothelial cells also secrete _ that is a vasoconstrictor
endothelin-1
endothelial cells regulate the traffic of
inflammatory cells
mother’s circulatory system does not exchange blood with the fetus, only materials carried in the blood; exchange occurs at the interface of what
umbilical cord fusing with the uterine walls (placenta)
the fetal side (syntrophoblast) consists of an outer layer of
multinucleated syncytiotrophoblasts
heart has 3 layers homologous to the 3 tunics of blood vessels
intima: endocardium
media: myocardium
adventitia: epicardium
Endocardium is lined by
endothelium that is continuous with blood vessels that enter and leave the heart
endocardium has a _ of fine collagenous fibers, a thin layer of dense _ connective tissue, and then a subendocardial layer of loose connective tissue connected to the myocardium
subendothelial layer
fibroelastic
subendocardial CT contains
blood vessels, nerves, and Purkinje fibers
in the ventricles, the myocardium is arranged into _ and _ layers
deep
superficial
_ myocardial layer has a spiral course around the ventricle
superficial
_ myocardial layer has a circular course around the ventricles
deep
the outermost coat of epicardium is formed by
mesothelial cells (note that the visceral layer of the serous pericardium is epicardial mesothelium)
underneath mesothelium of epicardium is loose CT and adipose tissue, which contains
the coronary blood vessels and nerves (adipose tissue contains these)
fibrous skeleton of heart is composed of
dense irregular connective tissue
fibrous portion of the interventricular septum
septum membranaceum
fibrous rings around the origins of the pulmonary artery, aorta, and atrioventricular canals
annuli fibrosi
fibrous tissue between the arterial foramina and the atrioventricular canals
trigona fibrosa
electrical continuity between myocardial cells of atria and ventricles controlled by specialized conduction tissue
A-V bundle
SA node fires and then
action potentials spread through atria
AV node fires and then
impulses go along conducting fibers
atrioventricular valves are
tricuspid and mitral valves
AV valves are connected to papillary muscles of the ventricles by fibrous cords called
chordae tendineae
semilunar valves exist between
ventricles and aorta and pulmonary artery
valves have both _ and _ layers surrounded by endothelium
dense and smooth CT layers
SA node is the _ of the heart
pacemaker
SA node contains _
modified cardiac muscle cells
AV node forms a common stem called the
AV bundle of His
AV bundle of His if formed by _ that are made of
Purkinje fibers
modified muscle cells filled with glycogen (important)
what is the source of polypeptide hormones
atrial cardiac muscle cells
what is released from modified atrial muscle cells in response to high blood pressure with the purpose to increase sodium and water secretion from kidney
atrial natriuretic peptide
