general characteristics of circulatory systems
1+ pumps/structures that apply force to drive fluid flow
system of tubes that the fluid can flow through
fluid that circulates through the system
bulk flow
aggregated movement of molecules together
allows fluids to move through an organism’s body faster than diffusion
what controls bulk flow of blood?
tubes, pumps, and valves
open circulatory system
heart type structure which is attached to tube-like structures whose ends are open to the rest of the organism
doesn’t allow huge control over the distribution of velocity of the system
closed circulatory system
heart and tubes are connected
supports relatively high pressures
evolved multiple times in animals
what does the high pressure in closed circulatory systems allow?
rapid adjustments in oxygen and nutrient delivery to specific issues
ultrafiltration of blood
artery
carries blood from the heart to capillary beds
vein
carries blood from capillary beds back to the heart
what is tunica externa made of?
collagen
what is tunica media made of?
smooth muscle and elastin
what is endothelium made from?
epithelial cells
elastic artery
has very thick tunica external
also has tunica media,, tunica intimate, and endothelium
muscular artery
has thinner tunica external, and thicker tunica media
also has tunica intima and endothelium
arteriole
has only tunica media surrounding endothelium
structures allows for its key role in blood distributions
leads into capillaries
capillary
specialized for transport of materials across the capillary bed
types: continuous, fenestrated, sinusoidal
continuous capillary
most common capillary type
present in the brain, muscles, and skin
fenestrated capillary
pores aid in movement of materials through the capillary beds
present in specialized organs (ex. kidneys, endocrine glands)
sinusoidal capillary
rare
has large intercellular lets, which allow protein movement
only found in the liver and in bone marrow
venule
only contains tunica externa and endothelium (NO MUSCLE)
vein
has tunica externa, a small tunica media, tunica intima, and endothelium
large vein
contain tunica externa, tunica media, tunica intima, and endothelium
Law of Bulk Flow
fluids flow down pressure gradient (from high pressure to low pressure)
Q = (delta)P/R
resistance opposes the flow of fluids
what can blood transport?
respiratory gases nutrients waste products hormones antibodies salts/ions
Ohm’s Law
I = V/R
equation for blood velocity
blood velocity = Q/A
where is blood velocity the lowest and cross sectional area the highest?
at the capillary beds
right atrium
receives blood from the body via the vena cava
superior vena cava
collects blood from the upper body
inferior vena cava
collects blood from the lower body
right AV valve
separates the right atrium from the right ventricle
aka the tricuspid valve
chordate tendineae
connects AV valves to the papillary muscles of the heart
semolina valve
separates the right ventricle from the pulmonary artery
pulmonary artery
transports blood to the lungs
left atrium
receives blood from the lungs
pulmonary veins
carry blood from the lungs to the left atrium
mitral valve
separates the left atrium from the left ventricle
aka the bicuspid valve
aorta
major artery of the heart
branches blood supply throughout the body
aortic semilunar valve
separates the aorta from the left ventricle
myocardium
makes up the muscle wall of the heart
is much thicker on the left side of the heart
thick in ventricles, thin in atria
is compact in mammals
supplied with its own circulation system via coronary arteries
endocardium
lining inside the heart
epicardium and parietal pericardium
two layers of pericardium
are separated by a fluid filled sac
diastole
relaxation of heart muscle
negative pressure
blood flows into heart
systole
contraction of heart muscle
positive pressure
blood flows out of the heart
SA node
has special characteristics that allow it to fire action potentials intrinsically
is the pacemaker of the heart
EKG
detects the integrated electrical activity of the whole heart
parts of an EKG
P-wave: atrial polarization
QRS complex: ventricular depolarization, atrial depolarization
T-wave: ventricular depolarization
what circulatory structure has the highest blood pressure? which structure has the lowest?
the left ventricle has the highest blood pressure; veins have the lowest
mean arterial pressure (MAP)
average blood pressure in the arteries across the cardiac cycle
baroreceptors
monitor blood pressure and signal to the cardiovascular control center of the medulla
what controls local flow of blood?
the diameter of arterioles
