Blood Vessels Vocabulary

arteries

carry blood away from the heart

sympathetic branch

division of the autonomic nervous system that carries signals related to your "fight or flight" response

vasoconstriction

narrowing of blood vessels by small muscles in their walls

vasodilation

widening of blood vessels as a result of the relaxation of the blood vessels' muscular walls

arterioles

small artery that delivers blood to capillaries

capillaries

microscopic vessels connect arterioles to venules, and which permit the exchange of nutrients and wastes between blood and tissue cells

venules

small veins formed by joining of several capillaries

veins

highly distensible, accommodating variable volumes of blood and acting as a blood reservoir

blood reservoir

an area from which a significant volume of blood can be rapidly redistributed in a precise and controlled way

blood pressure

the pressure exerted by blood on the wall of a blood vessel

arterial pressure

blood pressure is clinically referred to as this, which fluctuates in relation to ventricular systole and diastole

sphygmomanometer

indirectly measures arterial blood pressure; consists of an inflatable compression bag enclosed in a cuff and connected to a pressure gauge

baroreceptor reflex

series of quick actions your body takes to keep your blood pressure in a normal range in response to an abrupt change in position

vasomotor center

main center for neurogenic control of vascular tone and hence blood pressure; in the midbrain

hemostasis

prevents blood loss from small damaged blood vessels

prothrombinase (prothrombin activator)

responsible for the proteolytic conversion of prothrombin to thrombin

prothrombin

plasma protein formed by liver

thrombin

a proteolytic enzyme

fibrinogen

soluble plasma protein formed by liver

fibrin

insoluble protein

tissue factor (thromboplastin)

initiates prothrombinase; a factor extrinsic to blood

clot retraction

once a clot is formed contraction of the platelets within the clot shrinks the fibrin network, pulling the edges

plasmin

a fibrinolytic enzyme that slowly dissolves blood clots

thrombus

a clot which stays in the place where it is formed

thrombosis

the condition in which a clot stays in the place where it is formed

embolus

the part of the clot that dislodges, it circulates thru the bloodstream

embolism

a condition where part of a blood clot dislodges and circulates thru the bloodstream

atherosclerotic plaque

the mass of fatty substances and together with smooth muscle fibers that is deposited in the walls of medium and large sized arteries

coronary artery bypass graft

a procedure to bypass a blocked section of a coronary artery and to deliver oxygen to the heart