circulatory system part 2 Flashcards
ostia
crustacean heart - hemolymph returns to the heart through these holes
contains valves that open and close to regulate the flow
what controls the crustacean heart?
neurogenic
nervous system signals control contraction
what is the cardiac cycle in arthropods
neutrons spontaneously depolarize causing cardiomycotes to contract
decreases volume of heart, increases pressure
valves in ostia close, forcing blood to leave through arteries
ligaments pull on walls of heart increasing volume and decreasing pressure
valves in ostia open, sucking blood into heart
types of myocardium
mammal - compact
fish/amphibians - spongy
how many layers does the pericardium have?
2 layers
what are the four main parts of vertebrate heart walls?
pericardium
epicardium
myocardium
endocardium
pericardium
sac of connective tissue that surrounds heart
outer (parietal) and inner (visceral) layers
- space between layers filled with lubricating fluid
epicardium
outer layer of heart, continuous with visceral pericardium
contains nerves that regulate heart/ coronary arteries
myocardium
layer of heart muscle cells - cardiomycotes
spongy - meshwork of loosely connected (fish/amphibians)
compact - tightly packed cells arranged regularly (mammals, birds reptiles)
endocardium
innermost layer of connective tissue covered by epithelial cells (endothelium)
four chambers of fish hearts
sinus venosus
atrium
ventricle
bulbous arteriosus
fish heart cycle
passive valves open and close depending on pressure differences
unidirectional flow of blood
bulbous arteriousus does not contract but instead serves and pressure/ volume reservoir
amphibian heart
3 chambered: 2 atria and 1 ventricle
trabaculae - amphibian heart
in ventricle - helps prevent mixing of de/oxygenated blood
spiral fold in conus arteriosus - amphibian heart
helps direct deoxygenated blood to pulmocutaneous circuit and oxygenated blood to systemic circuit
reptile hearts
five chambered - 2 atria and 3 ventricles
caveum venosum- reptile hearts
leads to systemic aortas
caveum pulmonale
leads to pulmonary artery
caveum arteriosum
third compartment of ventricle
right to left shunt (reptile heart)
deoxygenated blood bypasses pulmonary circuit and enters systemic circuit
breath holding
left to right shunt
oxygenated blood reenters pulmonary circuit
helps oxygen delivery to myocardium
bird and mammals hearts
four chambers:
2 thin walled atria
2 thick walled ventricles
intraventricular septum - birds and mammals
separates ventricles
atrioventricular valves
between atria and ventricles
tricuspid - right
bicuspid (or mitral) - left
semi lunar valves
between ventricles and arteries
aortic - left ventricle and aorta
pulmonary - between right ventricle and pulmonary artery
phases of cardiac cycle (mammal heart)
systole - contraction - blood forced out diastole - relaxation - blood enters the heart
mammalian cardiac cycle
- ventricular diastole
- atrial systole
- ventricular systole (isovolumetric)
- ventricular systole (ventricular ejection)
- ventricular diastole
pressure in ventricles
left ventricle - contracts forcefully, higher pressure
right ventricle - lower resistance, less pressure to protect delicate blood vessels
velocity in blood
highest in arteries
middle in veins
lowest in capillaries
mean average arterial pressure in aorta
2/3 diastolic pressure + 1/3 systolic pressure
resisters in series
Rt= R1+R2
resisters in parallel
1/Rt = 1/R1 +1/R2
law of bulk flow
Q= P/R (pressure over resistance)
diffusion rate
CAD/X
concentration x surface area x diffusion coefficient / distance
