circulatory system part 2 Flashcards
Arthropod heart:
5 characteristics?
heart pumps hemolymph out of arteries
blood returns via OSTIA durning diastole
valves in ostia open and close to regulate flow
the heart is sustended with a series of ligaments
the heart is neurogenic (contractioon in response to signals from nervous system)
Cardiac cycle in arthropods:
neurons of cardiac ganglion undergo what?
spontaneous rhythmic depolarization
Vertebrate hearts:
what are the complex walls with four main parts called?
Pericardium
Epicardium
Myocardium
endocardium
What is the pericardium
sac of connective tissue that surrounds heart
outer(Parietal) and inner(visceral) layers
space between the layers filled with lubricating fluid
What is the epicardium?
outer layer of heart, continuous with visceral pericardium
contains nerves that regulate heart and coronary arteries
what is the myocardium?
layer of heart muscle cells (Cardiomyocytes)
What is the endocardium?
innermost layer of connective tissue covered by epithelial cells (called endothelium)
What are the two types of mycardium?
Compact - tightly packed cells arranged in regular pattern
spongy
-meshwork of loosely connected cells
Caracteristics of myocardium in mammals, birds, and reptiles?
mostely compact
characteristics of myocardium in fish and amphibians?
mostely spongy
arranged as trabeculae that extend into chambers
Fish heart characteristics?
four chambers arranged in series
sinus venosus
atrium
ventricles
bulbus arteriosus
Cardiac cycle of fish hearts?
serial contractions of chambers
valves are passive
opens and closes according to pressure differences
assure unidirectional flow of blood
noncontractile bulbus arteriosus serves as volume and pressure reservoir
Amphibian Hearts:
Three chambers two atria one ventrical
Trabeculae in ventrical- helps prevent mixing of oxygenated and deoxygenated blood in ventrical
spiral fold in conus arteriosus
-helps direct deoxygenated blood to pulmocutaneous circuit and oxygenated blood to systemic circuit
Reptile heart:
five chambered heart
two atria
threee interconnected ventricular compartments
cavum venosum-leads to systemic aortas
cavum pulmonale - leads to pulmonary artery
cavum arteriosum
seperation of oxygenated and deoxygenated blood in the venricle is nearly complete
Shunting in reptile hearts:
right to left
left to right
Can shunt blood to bypass pulmonary or systemic circuit
right to left shunt- deoxygenated blood bypasses pulmonary circuit and enters systemic circuit
(during breath holding)
left to right shunt
oxygenated blood reenters pulmonary circuit
aids oxygen delivery to myocardium
Bird and mammals hearts:
four chambers
two atria (thin walled)
two ventricles (thick walls, left ventricle thicker than right)
ventricles spereated by intraventricular septum
Bird and mammals:
valves
Atrioventricular (AV) valves
between atria and ventricles
tricupid on right
Bicuspid or mitral on left
Bird and mammals:
valves
Semilunar
between ventricles and arteries
AORTIC: between left ventrical and aorta
PULMONARY: between right ventricle and pulmonary artery
Hearts:
Cardiac syscle- pumping action of the hearts
systolic - contraction , blood is forced out into the circulation
Diastole- relaxation
blood enters the heart
Mammalian cardiac cycle:
atria and ventricals alternate systole and diastole
the two atria contract simultaneously
there is a slight pause
the two ventricales contract simultaneously
atria and ventricles relax while the heart fills with blood
Ventricular pressure:
left ventricle contracts more forcefully and develops higher pressure
resistance in pulmonary circuit low due to high capillary density in parallel (large cross sectional area)
less pressure needed to pump blood through pulmonary circuit
low pressure protects delicate blood vessels of lung
pressure in certebrate circulatory systems:
blood pressure in left ventricle changes with what?
changes is systolic and diastolic pressure
pressure in certebrate circulatory systems:
pressure decreases when?
as blood moves through system
ressure in certebrate circulatory systems:
pressure and pulse decrease in arterioles due to what?
due to increase in total cross sectional area
ressure in certebrate circulatory systems:
velocity of blood is highest where and least where?
highest in arteries, lowest in capillaries and intermediate in veins
Mean arterial pressure:
average arterial pressure in aorta over time?
MAP= 2/3 diastolic pressure + 1/3 systolic pressure
Blood velocity:
Flow (Q)
volume of fluid transferred per unit time
Blood velocity:
velocity?
distance per unit time
Blood velocity:
=Q/A
A= cross sectional area of the vessel
velocity of flow is inversely related to total cross sectional area
