Blood vessels Flashcards
What is the flow of blood?
Heart to arteries to arterioles to capillaries to venules to veins to heart
What are the 3 layers in the walls of blood vessels?
Tunica interna(intima)-deepest layer-simple squamous Tunica media-middle layer, mostly smooth muscle Tunica externa (adventitia)-superficial layer, mostly fibrous CT
Arteries
carry blood away from heart, thick walls to withstand high blood pressure
elastic arteries
larger arteries close to the heart, thickest walls - aorta, brachiocephalic trunk, common carotid arteries & subclavian arteries
muscular arteries
medium sized arteries further from heart, have high proportion of smooth muscle in tunica media- all arteries not listed as elastic arteries
arterioles
very small arteries leading to capillaries
Veins
carry blood towards the heart, thin walled, carry blood at low pressure, commonly equipped with valves to prevent backwards flow of blood due to gravity
venules
extremely small veins that drain blood from capillaries
capillaries
the smallest blood vessels that provide site for exchange of substances between the blood and other tissues
precapillary sphincters
control the flow of blood through the capillary beds, smooth muscle that respond to local controls
continuous capillaries
most common type of capillary found in almost all vascularized tissues, characterized by a complete endothelial lining with tight junctions between endothelial cells
intercellular clefts
small spaces between endothelial cells that allow substances to pass though the capillary wall
fenestrated capillaries
have pores (fenestrations) that make the capillary permeable to larger molecules and enable bulk flow to carry fluids at a higher rate *found in kidney, small intestine, and several endocrine organs
sinusoids
least common type of capillary have extensive intercellular gaps and incomplete basement membrane making them highly permeable to larger molecules and cells *found in liver, bone marrow, spleen and lymph nodes
What factors influence diffusion in capillary beds?
minimal diffusion distance
maximized surface area for exchange
maximized time for exchange (slow velocity of flow)
Left and Right coronary arteries
branch off from the ascending aorta
Circumflex artery
arises from left coronary and follows the coronary sulcus to the left
anterior interventricular artery
aka left anterior descending artery (LAD), second major branch arising from the left coronary artery
right coronary artery
proceeds along the coronary sulcus and distributes blood to the right atrium, portions of both ventricles and the heart conduction system
Marginal arteries
arise from the right coronary artery inferior to the right atrium, supply blood to the superficial portions of the right ventricle
posterior interventricular artery
aka posterior descending artery (PDA)-runs along posterior interventricular sulcus
coronary veins
drain the heart and generally parallel the large surface arteries
great cardiac vein
can be seen initially on the surface of the heart following the interventricular sulcus, but eventually flows along the coronary sulcus into the coronary sinus on the posterior surface, receives several major branches including the middle cardiac vein and the small cardiac vein
Middle cardiac vein
parallels posterior interventricular artery
small cardiac vein
drains the blood from the posterior surface of the right atrium and ventricle
coronary sinus
large, thin-walled vein on the posterior surface of the heart lying within the coronary sulcus and emptying directly into the right atrium
brachiocephalic artery
first branch off the aorta, travels superiorly towards the clavicle and branches into the right common carotid and the right subclavian
Left common carotid artery
second branch off the aorta, travels to the head
External carotid arteries
supplies skull outside cranium, terminates as superficial temporal artery
facial arteries
branch from the external carotid to supply the face
internal carotid arteries
supplies everything inside the cranium
vertebral arteries
first branch of the subclavian arteries, travels superiorly through cervical transvers foramen and then into the cranium through the foramen magnum
basilar artery
formed by the union of the right and left vertebral arteries
circle of willis
circles the pituitary gland, formed by anterior and posterior communicating arteries, connecting the right and left internal carotids and basilar artery
anterior cerebral arteries
branches anteriorly from the circle of willis. supplies the frontal lobe
middle cerebral arteries
supplies the temporal and parietal lobes
posterior cerebral arteries
branches off the basilar artery and supplies posterior cerebrum
superior sagittal sinus
runs sagitally along the top of the falx cerebri, drains to the transverse sinus to sigmoid sinus to internal jugular
internal jugular vein
receives most of the blood draining from the brain, drains into the subclavian veins forming the brachiocephalic veins
external jugular vein
drains scalp and face, empties into the subclavian veins
Left subclavian artery
third branch off the aorta, travels under the clavicle and turns into axillary artery
internal thoracic
arise from the subclavian and supply the anterior wall of the thoracic cavity
axillary artery
as subclavian reaches axillary region it becomes the axillary artery
brachial artery
axillary artery turns into the brachial as it runs along the humerus
radial artery
runs down the lateral aspect of the forearm
ulnar artery
runs down the medial aspect of the forearm
palmar arches
radial and ulnar arteries anastomose as deep and superficial palmar arches
Veins draining the arm
Palmar venous arches to radial or ulnar vein to brachial vein to axillary vein to subclavian vein to brachiocephalic to superior vena cava
basilic vein
drain palmar venous arches and runs along the medial underside of the arm, merges with the brachial vein to become the axillary vein
cephalic vein
runs along the lateral side of the arm and merges with axillary becoming subclavian vein
medial cubital
antecubital anastomosis of cephalic and basilic veins (common venipuncture site)
Azygos (“unpaired”) vein
ascends from the abdominal cavity along the right side of the vertebrae
Hemiazygos vein
crosses from left to right in front of thoracic vertebrae and joins the azygos vein
abdominal aorta
thoracic aorta becomes the abdominal aorta inferior to the diaphragm
inferior phrenic arteries
supply the diaphragm
celiac trunk
large unpaired branch off the aorta that branches into the common hepatic, the left gastric artery and the splenic artery
common hepatic artery
gives off branches to the liver as the hepatic artery proper
splenic artery
supplies the stomach, pancreas, and branches terminate in the spleen
left gastric artery
supplies the stomach and inferior esophagus
superior mesenteric
unpaired branch off the descending aorta, immediately below the celiac trunk-supplies small intestines and most of the large intestines
middle colic
branches from the superior mesenteric, supplies transverse colon
right colic
branches from superior mesenteric, supplies ascending colon
ileocolic
branches from superior mesenteric, supplies ilium and cecum
renal arteries
arise on the lateral surface of the abdominal aorta below the superior mesenteric
gonadal arteries
arise off the descending aorta between the superior and inferior mesenteric
inferior mesenteric
final major unpaired branch of the descending aorta, arises anteriorly and supplies blood to the distal portion of the large intestines and the rectum
left colic
branches off the inferior mesenteric, supplies descending colon
lumbar arteries
four pairs arise on the posterior of the aorta to supply the posterior abdominal wall
Veins draining the digestive organs
different drainage pattern that seen elsewhere. Superior mesenteric vein, inferior mesenteric vein, and the splenic vein drain into the hepatic portal vein, the liver is then drained by hepatic veins that empty into the inferior vena cava
superior mesenteric vein
drains the small intestines and part of the large intestines
inferior mesenteric vein
drains the distal portions of the large intestines, joins the splenic vein
splenic vein
drains spleen, stomach, and pancreas-joins superior mesenteric forming hepatic portal vein
hepatic veins
drain the liver and empty into the inferior vena cava
gonadal veins
the right empties into the inferior vena cava while the left empties into the renal vein
renal veins
drain the kidneys into the inferior vena cava
common iliac arteries
the descending abdominal aorta branches into the right and left common iliac
internal iliac arteries
branches from the common iliac and supplies the pelvic organs
external iliac arteries
passes under the inguinal ligament to become femoral
femoral arteries
travels down the anterior of femur, on posterior side it becomes popliteal artery behind knee, branches into posterior and anterior tibial arteries
dorsalis pedis
forms from the anterior tibial artery at the ankle
digital veins
drain into the plantar and dorsal venous arches
posterior tibial veins
drainsthe plantar venous arch and travels up the posterior tibia where it is joined by the fibular (peroneal) vein
anterior tibial veins
drains the dorsal venous arch and merges with the posterior tibial at the knee to form the popliteal vein
popliteal veins
crosses the knee and is joined by the small saphenous vein to form femoral vein
small saphenous vein
superficial vein, runs on the lateral aspect of the leg to the popliteal vein
femoral veins
drains the thigh. is joined proximally by the femoral circumflex, deep femoral vein, and the great saphenous vein. The femoral vein then crosses under the inguinal ligament and becomes the external iliac vein
great saphenous vein
longest vein in the body, runs on medial leg and thigh to the femoral vein
external iliac veins
joined by the internal iliac vein to become the common iliac vein
common iliac vein
right and left common iliac veins merge to become the inferior vena cava
