Chapter 42 Flashcards
circulatory system can be…
opened or closed
3 basic components of the circulatory system
circulatory fluid (blood or hemolymph) a set of tubes (blood vessels) muscular pump (the heart)
open circulatory system
blood bathes the organs directly
no distinction between blood and interstitial fluid (hemolymph)
present in insects and other anthropods
closed circulatory system
blood is confined to vessels
distinct from interstitial fluid
more efficient at transporting circulatory fluids to tissues and cells
cardiovascular system
closed
made up of 3 main types of blood vessels: arteries, veins
arteries
branch into arterioles
carry blood to capillaries
veins
converge form nevules
return blood from the capillaries to the heart
atrium
blood enters the heart
ventricle
blood leaves the heart
2 types of closed circulatory systems
single and double circulation
single circulation
blood leaving the heart passes through 2 capillary beads before returning
ex: bony fish, rays, sharks
double circulation
oxygen-poor blood and oxygen-rich blood are pumped separately from the right and left sides of the heart
maintains high blood pressure
double circulation in reptiles and mammals
oxygen-poor blood flows through the pulmonary circuit to pick up oxygen through the lungs
oxygen-rich blood delivers oxygen through the systemic circuit
cardiac cycle
heart contracts and relaxes in a rhythmic cycle
systole
contraction or pumping phase
diastole
relaxation or filling phase
heart rate
number of beats per minute
stroke volume
amount of blood pumped in a single contraction
cardiac output
volume of blood pumped into the systemic circulation per minute
depends in both heart rate and stroke volume
2 atrioventricular valves
separate each atrium and ventricle
2 semilunar valves
control blood flow to the aorta and the pulmonary artery
what is the sounds a heart beat males
Lub-dup
caused by the recoil of blood against the AV valves (lub)
pacemaker
sets the rate and timing at which cardiac muscle cells contract
blood flow velocity
slowest in the capillary beds due to high resistance
flow for exchange of material
blood pressure
hydrostatic pressure that blood exerts against the wall of a vessel
systolic pressure
pressure in the arteries during ventricular systole
diastolic pressure
pressure in the arteries during diastole
lower than systolic pressure
pulse
rhythmic bulging of artery walls with each heartbeat
vasoconstriction
contraction of smooth muscles in arteriole walls
increases blood pressure
vasodilation
relaxation of smooth arteriole walls
causes blood pressure to fall
components of blood
plasma (water, ions, proteins) cellular elements (red blood cells, white blood cells, platelets)
water in blood
solvent for carrying other substances
ions in blood
blood electrolytes
osmotic balance
pH buffer
regulation of membrane permeability
proteins in blood
osmotic balance
pH buffer
clotting
defense
red blood cells
erythrocytes
transport oxygen
white blood cells
leukocytes
defense
platelets
fragment cells
clotting
vasoconstriction and vasodilation help…
maintain adequate blood flow as the body’s demands change
