Key Terms

abdominal aorta

portion of the aorta inferior to the aortic hiatus and superior to the common iliac arteries

adrenal artery

branch of the abdominal aorta; supplies blood to the adrenal (suprarenal) glands

adrenal vein

drains the adrenal or suprarenal glands that are immediately superior to the kidneys; the right adrenal vein enters the inferior vena cava directly and the left adrenal vein enters the left renal vein

anaphylactic shock

type of shock that follows a severe allergic reaction and results from massive vasodilation

angioblasts

stem cells that give rise to blood vessels

angiogenesis

development of new blood vessels from existing vessels

anterior cerebral artery

arises from the internal carotid artery; supplies the frontal lobe of the cerebrum

anterior communicating artery

anastomosis of the right and left internal carotid arteries; supplies blood to the brain

anterior tibial artery

branches from the popliteal artery; supplies blood to the anterior tibial region; becomes the dorsalis pedis artery

anterior tibial vein

forms from the dorsal venous arch; drains the area near the tibialis anterior muscle and leads to the popliteal vein

aorta

largest artery in the body, originating from the left ventricle and descending to the abdominal region where it bifurcates into the common iliac arteries at the level of the fourth lumbar vertebra; arteries originating from the aorta distribute blood to virtually all tissues of the body

aortic arch

arc that connects the ascending aorta to the descending aorta; ends at the intervertebral disk between the fourth and fifth thoracic vertebrae

aortic hiatus

opening in the diaphragm that allows passage of the thoracic aorta into the abdominal region where it becomes the abdominal aorta

aortic sinuses

small pockets in the ascending aorta near the aortic valve that are the locations of the baroreceptors (stretch receptors) and chemoreceptors that trigger a reflex that aids in the regulation of vascular homeostasis

arterial circle

(also, circle of Willis) anastomosis located at the base of the brain that ensures continual blood supply; formed from branches of the internal carotid and vertebral arteries; supplies blood to the brain

arteriole

(also, resistance vessel) very small artery that leads to a capillary

arteriovenous anastomosis

short vessel connecting an arteriole directly to a venule and bypassing the capillary beds

artery

blood vessel that conducts blood away from the heart; may be a conducting or distributing vessel

ascending aorta

initial portion of the aorta, rising from the left ventricle for a distance of approximately 5 cm

atrial reflex

mechanism for maintaining vascular homeostasis involving atrial baroreceptors: if blood is returning to the right atrium more rapidly than it is being ejected from the left ventricle, the atrial receptors will stimulate the cardiovascular centers to increase sympathetic firing and increase cardiac output until the situation is reversed; the opposite is also true

axillary artery

continuation of the subclavian artery as it penetrates the body wall and enters the axillary region; supplies blood to the region near the head of the humerus (humeral circumflex arteries); the majority of the vessel continues into the brachium and becomes the brachial artery

axillary vein

major vein in the axillary region; drains the upper limb and becomes the subclavian vein

azygos vein

originates in the lumbar region and passes through the diaphragm into the thoracic cavity on the right side of the vertebral column; drains blood from the intercostal veins, esophageal veins, bronchial veins, and other veins draining the mediastinal region; leads to the superior vena cava

basilar artery

formed from the fusion of the two vertebral arteries; sends branches to the cerebellum, brain stem, and the posterior cerebral arteries; the main blood supply to the brain stem

basilic vein

superficial vein of the arm that arises from the palmar venous arches, intersects with the median cubital vein, parallels the ulnar vein, and continues into the upper arm; along with the brachial vein, it leads to the axillary vein

blood colloidal osmotic pressure (BCOP)

pressure exerted by colloids suspended in blood within a vessel; a primary determinant is the presence of plasma proteins

blood flow

movement of blood through a vessel, tissue, or organ that is usually expressed in terms of volume per unit of time

blood hydrostatic pressure

force blood exerts against the walls of a blood vessel or heart chamber

blood islands

masses of developing blood vessels and formed elements from mesodermal cells scattered throughout the embryonic disc

blood pressure

force exerted by the blood against the wall of a vessel or heart chamber; can be described with the more generic term hydrostatic pressure

brachial artery

continuation of the axillary artery in the brachium; supplies blood to much of the brachial region; gives off several smaller branches that provide blood to the posterior surface of the arm in the region of the elbow; bifurcates into the radial and ulnar arteries at the coronoid fossa

brachial vein

deeper vein of the arm that forms from the radial and ulnar veins in the lower arm; leads to the axillary vein

brachiocephalic artery

single vessel located on the right side of the body; the first vessel branching from the aortic arch; gives rise to the right subclavian artery and the right common carotid artery; supplies blood to the head, neck, upper limb, and wall of the thoracic region

brachiocephalic vein

one of a pair of veins that form from a fusion of the external and internal jugular veins and the subclavian vein; subclavian, external and internal jugulars, vertebral, and internal thoracic veins lead to it; drains the upper thoracic region and flows into the superior vena cava

bronchial artery

systemic branch from the aorta that provides oxygenated blood to the lungs in addition to the pulmonary circuit

bronchial vein

drains the systemic circulation from the lungs and leads to the azygos vein

capacitance

ability of a vein to distend and store blood

capacitance vessels

veins

capillary

smallest of blood vessels where physical exchange occurs between the blood and tissue cells surrounded by interstitial fluid

capillary bed

network of 10–100 capillaries connecting arterioles to venules

capillary hydrostatic pressure (CHP)

force blood exerts against a capillary

cardiogenic shock

type of shock that results from the inability of the heart to maintain cardiac output

carotid sinuses

small pockets near the base of the internal carotid arteries that are the locations of the baroreceptors and chemoreceptors that trigger a reflex that aids in the regulation of vascular homeostasis

cavernous sinus

enlarged vein that receives blood from most of the other cerebral veins and the eye socket, and leads to the petrosal sinus

celiac trunk

(also, celiac artery) major branch of the abdominal aorta; gives rise to the left gastric artery, the splenic artery, and the common hepatic artery that forms the hepatic artery to the liver, the right gastric artery to the stomach, and the cystic artery to the gall bladder

cephalic vein

superficial vessel in the upper arm; leads to the axillary vein

cerebrovascular accident (CVA)

blockage of blood flow to the brain; also called a stroke

circle of Willis

(also, arterial circle) anastomosis located at the base of the brain that ensures continual blood supply; formed from branches of the internal carotid and vertebral arteries; supplies blood to the brain

circulatory shock

also simply called shock; a life-threatening medical condition in which the circulatory system is unable to supply enough blood flow to provide adequate oxygen and other nutrients to the tissues to maintain cellular metabolism

common carotid artery

right common carotid artery arises from the brachiocephalic artery, and the left common carotid arises from the aortic arch; gives rise to the external and internal carotid arteries; supplies the respective sides of the head and neck

common hepatic artery

branch of the celiac trunk that forms the hepatic artery, the right gastric artery, and the cystic artery

common iliac artery

branch of the aorta that leads to the internal and external iliac arteries

common iliac vein

one of a pair of veins that flows into the inferior vena cava at the level of L5; the left common iliac vein drains the sacral region; divides into external and internal iliac veins near the inferior portion of the sacroiliac joint

compliance

degree to which a blood vessel can stretch as opposed to being rigid

continuous capillary

most common type of capillary, found in virtually all tissues except epithelia and cartilage; contains very small gaps in the endothelial lining that permit exchange

cystic artery

branch of the common hepatic artery; supplies blood to the gall bladder

deep femoral artery

branch of the femoral artery; gives rise to the lateral circumflex arteries

deep femoral vein

drains blood from the deeper portions of the thigh and leads to the femoral vein

descending aorta

portion of the aorta that continues downward past the end of the aortic arch; subdivided into the thoracic aorta and the abdominal aorta

diastolic pressure

lower number recorded when measuring arterial blood pressure; represents the minimal value corresponding to the pressure that remains during ventricular relaxation

digital arteries

formed from the superficial and deep palmar arches; supply blood to the digits

digital veins

drain the digits and feed into the palmar arches of the hand and dorsal venous arch of the foot

dorsal arch

(also, arcuate arch) formed from the anastomosis of the dorsalis pedis artery and medial and plantar arteries; branches supply the distal portions of the foot and digits

dorsal venous arch

drains blood from digital veins and vessels on the superior surface of the foot

dorsalis pedis artery

forms from the anterior tibial artery; branches repeatedly to supply blood to the tarsal and dorsal regions of the foot

ductus arteriosus

shunt in the fetal pulmonary trunk that diverts oxygenated blood back to the aorta

ductus venosus

shunt that causes oxygenated blood to bypass the fetal liver on its way to the inferior vena cava

elastic artery

(also, conducting artery) artery with abundant elastic fibers located closer to the heart, which maintains the pressure gradient and conducts blood to smaller branches

esophageal artery

branch of the thoracic aorta; supplies blood to the esophagus

esophageal vein

drains the inferior portions of the esophagus and leads to the azygos vein

external carotid artery

arises from the common carotid artery; supplies blood to numerous structures within the face, lower jaw, neck, esophagus, and larynx

external elastic membrane

membrane composed of elastic fibers that separates the tunica media from the tunica externa; seen in larger arteries

external iliac artery

branch of the common iliac artery that leaves the body cavity and becomes a femoral artery; supplies blood to the lower limbs

external iliac vein

formed when the femoral vein passes into the body cavity; drains the legs and leads to the common iliac vein

external jugular vein

one of a pair of major veins located in the superficial neck region that drains blood from the more superficial portions of the head, scalp, and cranial regions, and leads to the subclavian vein

femoral artery

continuation of the external iliac artery after it passes through the body cavity; divides into several smaller branches, the lateral deep femoral artery, and the genicular artery; becomes the popliteal artery as it passes posterior to the knee

femoral circumflex vein

forms a loop around the femur just inferior to the trochanters; drains blood from the areas around the head and neck of the femur; leads to the femoral vein

femoral vein

drains the upper leg; receives blood from the great saphenous vein, the deep femoral vein, and the femoral circumflex vein; becomes the external iliac vein when it crosses the body wall

fenestrated capillary

type of capillary with pores or fenestrations in the endothelium that allow for rapid passage of certain small materials

fibular vein

drains the muscles and integument near the fibula and leads to the popliteal vein

filtration

in the cardiovascular system, the movement of material from a capillary into the interstitial fluid, moving from an area of higher pressure to lower pressure

foramen ovale

shunt that directly connects the right and left atria and helps to divert oxygenated blood from the fetal pulmonary circuit

genicular artery

branch of the femoral artery; supplies blood to the region of the knee

gonadal artery

branch of the abdominal aorta; supplies blood to the gonads or reproductive organs; also described as ovarian arteries or testicular arteries, depending upon the sex of the individual

gonadal vein

generic term for a vein draining a reproductive organ; may be either an ovarian vein or a testicular vein, depending on the sex of the individual

great cerebral vein

receives most of the smaller vessels from the inferior cerebral veins and leads to the straight sinus

great saphenous vein

prominent surface vessel located on the medial surface of the leg and thigh; drains the superficial portions of these areas and leads to the femoral vein

hemangioblasts

embryonic stem cells that appear in the mesoderm and give rise to both angioblasts and pluripotent stem cells

hemiazygos vein

smaller vein complementary to the azygos vein; drains the esophageal veins from the esophagus and the left intercostal veins, and leads to the brachiocephalic vein via the superior intercostal vein

hepatic artery proper

branch of the common hepatic artery; supplies systemic blood to the liver

hepatic portal system

specialized circulatory pathway that carries blood from digestive organs to the liver for processing before being sent to the systemic circulation

hepatic vein

drains systemic blood from the liver and flows into the inferior vena cava

hypertension

chronic and persistent blood pressure measurements of 140/90 mm Hg or above

hypervolemia

abnormally high levels of fluid and blood within the body

hypovolemia

abnormally low levels of fluid and blood within the body

hypovolemic shock

type of circulatory shock caused by excessive loss of blood volume due to hemorrhage or possibly dehydration

hypoxia

lack of oxygen supply to the tissues

inferior mesenteric artery

branch of the abdominal aorta; supplies blood to the distal segment of the large intestine and rectum

inferior phrenic artery

branch of the abdominal aorta; supplies blood to the inferior surface of the diaphragm

inferior vena cava

large systemic vein that drains blood from areas largely inferior to the diaphragm; empties into the right atrium

intercostal artery

branch of the thoracic aorta; supplies blood to the muscles of the thoracic cavity and vertebral column

intercostal vein

drains the muscles of the thoracic wall and leads to the azygos vein

internal carotid artery

arises from the common carotid artery and begins with the carotid sinus; goes through the carotid canal of the temporal bone to the base of the brain; combines with branches of the vertebral artery forming the arterial circle; supplies blood to the brain

internal elastic membrane

membrane composed of elastic fibers that separates the tunica intima from the tunica media; seen in larger arteries

internal iliac artery

branch from the common iliac arteries; supplies blood to the urinary bladder, walls of the pelvis, external genitalia, and the medial portion of the femoral region; in females, also provide blood to the uterus and vagina

internal iliac vein

drains the pelvic organs and integument; formed from several smaller veins in the region; leads to the common iliac vein

internal jugular vein

one of a pair of major veins located in the neck region that passes through the jugular foramen and canal, flows parallel to the common carotid artery that is more or less its counterpart; primarily drains blood from the brain, receives the superficial facial vein, and empties into the subclavian vein

internal thoracic artery

(also, mammary artery) arises from the subclavian artery; supplies blood to the thymus, pericardium of the heart, and the anterior chest wall

internal thoracic vein

(also, internal mammary vein) drains the anterior surface of the chest wall and leads to the brachiocephalic vein

interstitial fluid colloidal osmotic pressure (IFCOP)

pressure exerted by the colloids within the interstitial fluid

interstitial fluid hydrostatic pressure (IFHP)

force exerted by the fluid in the tissue spaces

ischemia

insufficient blood flow to the tissues

Korotkoff sounds

noises created by turbulent blood flow through the vessels

lateral circumflex artery

branch of the deep femoral artery; supplies blood to the deep muscles of the thigh and the ventral and lateral regions of the integument

lateral plantar artery

arises from the bifurcation of the posterior tibial arteries; supplies blood to the lateral plantar surfaces of the foot

left gastric artery

branch of the celiac trunk; supplies blood to the stomach

lumbar arteries

branches of the abdominal aorta; supply blood to the lumbar region, the abdominal wall, and spinal cord

lumbar veins

drain the lumbar portion of the abdominal wall and spinal cord; the superior lumbar veins drain into the azygos vein on the right or the hemiazygos vein on the left; blood from these vessels is returned to the superior vena cava rather than the inferior vena cava

lumen

interior of a tubular structure such as a blood vessel or a portion of the alimentary canal through which blood, chyme, or other substances travel

maxillary vein

drains blood from the maxillary region and leads to the external jugular vein

mean arterial pressure (MAP)

average driving force of blood to the tissues; approximated by taking diastolic pressure and adding 1/3 of pulse pressure

medial plantar artery

arises from the bifurcation of the posterior tibial arteries; supplies blood to the medial plantar surfaces of the foot

median antebrachial vein

vein that parallels the ulnar vein but is more medial in location; intertwines with the palmar venous arches

median cubital vein

superficial vessel located in the antecubital region that links the cephalic vein to the basilic vein in the form of a v; a frequent site for a blood draw

median sacral artery

continuation of the aorta into the sacrum

mediastinal artery

branch of the thoracic aorta; supplies blood to the mediastinum

metarteriole

short vessel arising from a terminal arteriole that branches to supply a capillary bed

microcirculation

blood flow through the capillaries

middle cerebral artery

another branch of the internal carotid artery; supplies blood to the temporal and parietal lobes of the cerebrum

middle sacral vein

drains the sacral region and leads to the left common iliac vein

muscular artery

(also, distributing artery) artery with abundant smooth muscle in the tunica media that branches to distribute blood to the arteriole network

myogenic response

constriction or dilation in the walls of arterioles in response to pressures related to blood flow; reduces high blood flow or increases low blood flow to help maintain consistent flow to the capillary network

nervi vasorum

small nerve fibers found in arteries and veins that trigger contraction of the smooth muscle in their walls

net filtration pressure (NFP)

force driving fluid out of the capillary and into the tissue spaces; equal to the difference of the capillary hydrostatic pressure and the blood colloidal osmotic pressure

neurogenic shock

type of shock that occurs with cranial or high spinal injuries that damage the cardiovascular centers in the medulla oblongata or the nervous fibers originating from this region

obstructive shock

type of shock that occurs when a significant portion of the vascular system is blocked

occipital sinus

enlarged vein that drains the occipital region near the falx cerebelli and flows into the left and right transverse sinuses, and also into the vertebral veins

ophthalmic artery

branch of the internal carotid artery; supplies blood to the eyes

ovarian artery

branch of the abdominal aorta; supplies blood to the ovary, uterine (Fallopian) tube, and uterus

ovarian vein

drains the ovary; the right ovarian vein leads to the inferior vena cava and the left ovarian vein leads to the left renal vein

palmar arches

superficial and deep arches formed from anastomoses of the radial and ulnar arteries; supply blood to the hand and digital arteries

palmar venous arches

drain the hand and digits, and feed into the radial and ulnar veins

parietal branches

(also, somatic branches) group of arterial branches of the thoracic aorta; includes those that supply blood to the thoracic cavity, vertebral column, and the superior surface of the diaphragm

perfusion

distribution of blood into the capillaries so the tissues can be supplied

pericardial artery

branch of the thoracic aorta; supplies blood to the pericardium

petrosal sinus

enlarged vein that receives blood from the cavernous sinus and flows into the internal jugular vein

phrenic vein

drains the diaphragm; the right phrenic vein flows into the inferior vena cava and the left phrenic vein leads to the left renal vein

plantar arch

formed from the anastomosis of the dorsalis pedis artery and medial and plantar arteries; branches supply the distal portions of the foot and digits

plantar veins

drain the foot and lead to the plantar venous arch

plantar venous arch

formed from the plantar veins; leads to the anterior and posterior tibial veins through anastomoses

popliteal artery

continuation of the femoral artery posterior to the knee; branches into the anterior and posterior tibial arteries

popliteal vein

continuation of the femoral vein behind the knee; drains the region behind the knee and forms from the fusion of the fibular and anterior and posterior tibial veins

posterior cerebral artery

branch of the basilar artery that forms a portion of the posterior segment of the arterial circle; supplies blood to the posterior portion of the cerebrum and brain stem

posterior communicating artery

branch of the posterior cerebral artery that forms part of the posterior portion of the arterial circle; supplies blood to the brain

posterior tibial artery

branch from the popliteal artery that gives rise to the fibular or peroneal artery; supplies blood to the posterior tibial region

posterior tibial vein

forms from the dorsal venous arch; drains the area near the posterior surface of the tibia and leads to the popliteal vein

precapillary sphincters

circular rings of smooth muscle that surround the entrance to a capillary and regulate blood flow into that capillary

pulmonary artery

one of two branches, left and right, that divides off from the pulmonary trunk and leads to smaller arterioles and eventually to the pulmonary capillaries

pulmonary circuit

system of blood vessels that provide gas exchange via a network of arteries, veins, and capillaries that run from the heart, through the body, and back to the lungs

pulmonary trunk

single large vessel exiting the right ventricle that divides to form the right and left pulmonary arteries

pulmonary veins

two sets of paired vessels, one pair on each side, that are formed from the small venules leading away from the pulmonary capillaries that flow into the left atrium

pulse

alternating expansion and recoil of an artery as blood moves through the vessel; an indicator of heart rate

pulse pressure

difference between the systolic and diastolic pressures

radial artery

formed at the bifurcation of the brachial artery; parallels the radius; gives off smaller branches until it reaches the carpal region where it fuses with the ulnar artery to form the superficial and deep palmar arches; supplies blood to the lower arm and carpal region

radial vein

parallels the radius and radial artery; arises from the palmar venous arches and leads to the brachial vein

reabsorption

in the cardiovascular system, the movement of material from the interstitial fluid into the capillaries

renal artery

branch of the abdominal aorta; supplies each kidney

renal vein

largest vein entering the inferior vena cava; drains the kidneys and leads to the inferior vena cava

resistance

any condition or parameter that slows or counteracts the flow of blood

respiratory pump

increase in the volume of the thorax during inhalation that decreases air pressure, enabling venous blood to flow into the thoracic region, then exhalation increases pressure, moving blood into the atria

right gastric artery

branch of the common hepatic artery; supplies blood to the stomach

sepsis

(also, septicemia) organismal-level inflammatory response to a massive infection

septic shock

(also, blood poisoning) type of shock that follows a massive infection resulting in organism-wide inflammation

sigmoid sinuses

enlarged veins that receive blood from the transverse sinuses; flow through the jugular foramen and into the internal jugular vein

sinusoid capillary

rarest type of capillary, which has extremely large intercellular gaps in the basement membrane in addition to clefts and fenestrations; found in areas such as the bone marrow and liver where passage of large molecules occurs

skeletal muscle pump

effect on increasing blood pressure within veins by compression of the vessel caused by the contraction of nearby skeletal muscle

small saphenous vein

located on the lateral surface of the leg; drains blood from the superficial regions of the lower leg and foot, and leads to the popliteal vein

sphygmomanometer

blood pressure cuff attached to a device that measures blood pressure

splenic artery

branch of the celiac trunk; supplies blood to the spleen

straight sinus

enlarged vein that drains blood from the brain; receives most of the blood from the great cerebral vein and flows into the left or right transverse sinus

subclavian artery

right subclavian arises from the brachiocephalic artery, whereas the left subclavian artery arises from the aortic arch; gives rise to the internal thoracic, vertebral, and thyrocervical arteries; supplies blood to the arms, chest, shoulders, back, and central nervous system

subclavian vein

located deep in the thoracic cavity; becomes the axillary vein as it enters the axillary region; drains the axillary and smaller local veins near the scapular region; leads to the brachiocephalic vein

subscapular vein

drains blood from the subscapular region and leads to the axillary vein

superior mesenteric artery

branch of the abdominal aorta; supplies blood to the small intestine (duodenum, jejunum, and ileum), the pancreas, and a majority of the large intestine

superior phrenic artery

branch of the thoracic aorta; supplies blood to the superior surface of the diaphragm

superior sagittal sinus

enlarged vein located midsagittally between the meningeal and periosteal layers of the dura mater within the falx cerebri; receives most of the blood drained from the superior surface of the cerebrum and leads to the inferior jugular vein and the vertebral vein

superior vena cava

large systemic vein; drains blood from most areas superior to the diaphragm; empties into the right atrium

systolic pressure

larger number recorded when measuring arterial blood pressure; represents the maximum value following ventricular contraction

temporal vein

drains blood from the temporal region and leads to the external jugular vein

testicular artery

branch of the abdominal aorta; will ultimately travel outside the body cavity to the testes and form one component of the spermatic cord

testicular vein

drains the testes and forms part of the spermatic cord; the right testicular vein empties directly into the inferior vena cava and the left testicular vein empties into the left renal vein

thoracic aorta

portion of the descending aorta superior to the aortic hiatus

thoroughfare channel

continuation of the metarteriole that enables blood to bypass a capillary bed and flow directly into a venule, creating a vascular shunt

thyrocervical artery

arises from the subclavian artery; supplies blood to the thyroid, the cervical region, the upper back, and shoulder

transient ischemic attack (TIA)

temporary loss of neurological function caused by a brief interruption in blood flow; also known as a mini-stroke

transverse sinuses

pair of enlarged veins near the lambdoid suture that drain the occipital, sagittal, and straight sinuses, and leads to the sigmoid sinuses

trunk

large vessel that gives rise to smaller vessels

tunica externa

(also, tunica adventitia) outermost layer or tunic of a vessel (except capillaries)

tunica intima

(also, tunica interna) innermost lining or tunic of a vessel

tunica media

middle layer or tunic of a vessel (except capillaries)

ulnar artery

formed at the bifurcation of the brachial artery; parallels the ulna; gives off smaller branches until it reaches the carpal region where it fuses with the radial artery to form the superficial and deep palmar arches; supplies blood to the lower arm and carpal region

ulnar vein

parallels the ulna and ulnar artery; arises from the palmar venous arches and leads to the brachial vein

umbilical arteries

pair of vessels that runs within the umbilical cord and carries fetal blood low in oxygen and high in waste to the placenta for exchange with maternal blood

umbilical vein

single vessel that originates in the placenta and runs within the umbilical cord, carrying oxygen- and nutrient-rich blood to the fetal heart

vasa vasorum

small blood vessels located within the walls or tunics of larger vessels that supply nourishment to and remove wastes from the cells of the vessels

vascular shock

type of shock that occurs when arterioles lose their normal muscular tone and dilate dramatically

vascular shunt

continuation of the metarteriole and thoroughfare channel that allows blood to bypass the capillary beds to flow directly from the arterial to the venous circulation

vascular tone

contractile state of smooth muscle in a blood vessel

vascular tubes

rudimentary blood vessels in a developing fetus

vasoconstriction

constriction of the smooth muscle of a blood vessel, resulting in a decreased vascular diameter

vasodilation

relaxation of the smooth muscle in the wall of a blood vessel, resulting in an increased vascular diameter

vasomotion

irregular, pulsating flow of blood through capillaries and related structures

vein

blood vessel that conducts blood toward the heart

venous reserve

volume of blood contained within systemic veins in the integument, bone marrow, and liver that can be returned to the heart for circulation, if needed

venule

small vessel leading from the capillaries to veins

vertebral artery

arises from the subclavian artery and passes through the vertebral foramen through the foramen magnum to the brain; joins with the internal carotid artery to form the arterial circle; supplies blood to the brain and spinal cord

vertebral vein

arises from the base of the brain and the cervical region of the spinal cord; passes through the intervertebral foramina in the cervical vertebrae; drains smaller veins from the cranium, spinal cord, and vertebrae, and leads to the brachiocephalic vein; counterpart of the vertebral artery

visceral branches

branches of the descending aorta that supply blood to the viscera