circulatory system Flashcards
substances transported by the circulatory system
gases, solutes, hormones, antibodies, waste, heat, and force
peristaltic pump
movement through a multi chambered pump via peristalsis, most common in invertebrates
chambered pump
the 2, 3, or 4 chambered heart in vertebrates
movement of blood in the circulatory system
movement via one way valves
elastic recoil
allows the arteries to expand and exert an inward force creating blood pressure
open circulatory systems
blood vessels from one large heart and several smaller hearts move hemolymph throughout the body; no pick up and delivery, just circulation around the body
closed circulatory system
smaller blood volume under high pressure, blood flow is highly regulated picking up and delivering oxygen, allows for a higher metabolic rate
water breathing organisms
water has unidirectional countercurrent flow over the gills allows pick up of more oxygen, lower metabolic rates than air breathers, single circuit heart > pulmonary > systemic > heart
air breathing organisms
greater degree of separation of the pulmonary and systemic systems accompanied by increased blood pressure
lungfish
have gills and lungs, blood flow is controlled by the ductus and the modified structure of the heart
circulatory system of amphibians and most reptiles
have a right and left atrium and 1 ventricle with incomplete separation; systemic artery > tissues > right atrium > pulmocutaneous artery > skin > right atrium OR pulmocutaneous artery > lungs > pulmonary vein > left atrium
foramen of panizzae
diving adaptation in crocodilians that bypasses transport of blood to the lungs to remain underwater, also aids in digestion
circulatory system of crocodilians
right atrium > right ventricle > lungs > left atrium > left ventricle > systemic system through left aorta; no mixing left and right aorta controlled by foramen of panizzae
vascular component to blood flow
flow rate is determined by the pressure gradient divided by resistance
resistance
(8viscositylength of blood vessel)/pi*r^4; radius of the blood vessels is the biggest determining factor
arteries
high pressure flow, variable in size
arterioles
resistance vessels lined with smooth muscle, regulate blood flow to tissues, able to contract and dilate; site of pressure regulation
capillaries
act in nutrient exchange, very abundant and close in proximity to the tissue it is delivering to, only 1 cell layer thick, found in the pulmonary and systemic circuits, sphincters only open 10% at rest
venules
accept or hold blood with very little muscle involved, low blood pressure
veins
capacitance vessels, at any given time roughly 60% of all blood is here, 19x more compliant than arteries, low resistance, return blood to the heart, regulate venous return
systolic blood pressure
pressure in your arteries when the heart beats; increases with exercise
diastolic blood pressure
pressure in the arteries when the heart is resting between beats; remains constant with exercise
hydraulic filter
arterial system converts intermittent pumping of the heart to a steady flow of blood through the capillaries; known as the windkessel effect
hydrostatic and osmotic pressure
determine net filtration pressure of the capillaries; hydrostatic pressure drops over the length but osmotic pressure stays the same this results in nutrients moving in at the venous end pushing out plasma containing dissolved solutes
factors influencing venous return
cardiac concentration, skeletal muscle activity, respiratory activity, sympathetic activity, venous valves, cardiac suction
baroreceptors
sense CO2 in the venous system and signal when excess CO2 needs removed to the CNS triggering parasympathetic and sympathetic control of the circulatory and respiratory systems
blood loss
arterial pressure decreases leading to either baroreceptor reflex to increase heart rate and vasoconstriction to increase blood pressure; OR capillary pressure decreases which increases fluid absorption from the interstitial compartment which increases plasma volume
blood clotting
prevents uncontrolled blood lass via local vasoconstriction, formation of a platelet plug and blood coagulation; a positive feedback loop
platelet plug
activated by tissue damage, platelets stick to collagen, ATP and arachidonic acid are released which increases stickiness and aggregation stimulating further vasoconstriction
blood coagulation
dominant hemostatic defense, conversion of fibrinogen to fibrin followed by a cascade reaction
3 steps of blood coagulation
prothrombin is activated and factor x is formed in response to tissue damage which creates thrombin, thrombin and fibrinogen form fibrin which enmeshes platelets and blood cells; calcium is a cofactor for many steps; thrombin affects platelet aggregation
hemophilia
A - clotting factor VIII is missing or low; B - clotting factor IX is missing or low
anticoagulants
prevent the blood clotting cascade from happening; includes antithrombin III and heparin which are also released by leaches
anticlotting mechanisms
anticoagulants, lysis breaks down binds in fibrin strands via plasmin, short lived and local products
