Final: Circulation 3 Flashcards
birds and mammals: heart structure (5)
- endothelium connective tissue which directly contacts blood
- endocardium
- myocardium
- coronary arteries
- pericardium consisting of: epicardium, pericardial fluid in pericardial cavity, and the parietal pericardium
fish: heart structure (6)
- endocardium that covers the trabeculae
- spongy myocardium
- compact myocardium
- coronary arteries (only in very active fish)
- pericardial cavity
- pericardium
which fish have coronary arteries and examples (2)
- very active fish; most don’t have coronary arteries
- eg. tuna and sharks
vertebrate heart walls (4)
- pericardium
- epicardium
- myocardium
- endocardium
vertebrate heart: pericardium (3)
- sac of connective tissue that surrounds the heart
- outer (parietal) and inner (visceral) layers
- space between the layers is filled with lubricating fluid
vertebrate heart: epicardium (2)
- outer layer of heart, continuous with the visceral pericardium
- contain nerves that regulate heart and coronary arteries
vertebrate heart: myocardium
- layer of heart muscle cells (cardiomyocytes)
vertebrate heart: endocardium (2)
- innermost layer of connective tissue covered by epithelial cells (called endothelium)
- directly contacts the blood
myocardium types (2)
- compact
- spongy
compact myocardium (2)
- tightly packed cells arranged in regular pattern
- much more muscle than spongy myocardium (more compact), increasing the ability to do work to support metabolism
spongy myocardium (3)
- meshwork of loosely connected cells
- cells get bathed by blood entering the heart to obtain O2 and get rid of CO2
- allows for greater surface area for gas exchange
myocardium: mammals
- mostly have compact myocardium
myocardium: fish and amphibians (2)
- mostly have spongy myocardium, but active fishes can have more compact myocardium
- arranged as trabecular that extend into chambers
why does oxygen needed to be supplied to the heart
- myocardium is extremely oxidative and has a high O2 demand
how do mammals and birds obtain O2 to the heart
- coronary arteries supply oxygen to compact myocardium
how do fish obtain O2 to the heart
- spongy myocardium obtains oxygen from blood flowing through the heart
fish hearts (3)
- chambers
- separation
- myocardium
- four chambers arranged in series
- only deoxygenated blood passes through the heart
- spongy myocardium
fish heart chambers (4)
- sinus venosus
- atrium
- ventricle
- bulbus arteriosus
amphibian hearts (3)
- chambers
- separation
- myocardium
- three-chambered heart
- partial separation of oxygenated and deoxygenated blood; the beginning of separation in heart
- spongy myocardium
amphibian heart: chambers (3)
- two atria
- one ventricle
- conus arteriosus
amphibian heart: ventricle (2)
- trabecular in ventricle
- helps to prevent mixing of oxygenated and deoxygenated blood in the ventricle
amphibian heart: right atrium (2)
- contains the sinus venosus
- receives deoxygenated blood
amphibian heart: left atrium
- receives oxygenated blood from the pulmonary vein
amphibian heart: conus arteriosus (2)
- contains a spiral fold
- helps direct deoxygenated blood to pulmocutaneous circuit and oxygenated blood to the systemic circuit
circulatory pattern in amphibians (5)
- oxygenated blood leaves the heart and enters the aorta
- blood is delivered to the tissues, where it becomes deoxygenated
- deoxygenated blood enters the right atrium, where it mixes with oxygenated blood coming back from the skin (cutaneous respiration)
- blood is pumped from the ventricle into the pulmocutaneous artery, where it becomes oxygenated at the lungs or at the skin
- oxygenated blood enters the heart through the left atrium
reptile hearts (3)
- chambers
- separation
- myocardium
- five-chambered heart
- separation of oxygenated and deoxygenate blood in ventricle is nearly complete
- compact myocardium
reptile heart: chambers (2)
- two atria
- three interconnected ventricular compartments, which allow for good degree of blood separation
reptile heart: interconnected ventricular compartments (3)
- cavum venosum
- cavum pulmonale
- cavum arteriosum
reptile heart: cavum arteriosum
- receives blood from left atrium and leads to the cavum venosum
reptile heart: cavum venosum
- leads to systemic aortas
reptile heart: cavum pulmonale
- leads to pulmonary artery
reptile heart: shunts (2)
- reptiles can shunt blood to bypass the pulmonary circuit or systemic circuit
- can be a right-to-left shunt or a left-to-right shunt
reptile heart: right-to-left shunt (2)
- deoxygenated blood bypasses pulmonary circuit and enters systemic circuit, bypassing the lungs
- thought to be active during breath-holding
reptile heart: left-to-right shunt (2)
- oxygenated blood re-enters the pulmonary circuit, bypassing the peripheral tissue
- thought to be active when aiding in oxygen delivery to the myocardium in the right heart
circulatory pattern in reptiles (5)
- oxygenated blood leaves the cavum venosum and enters the systemic aortas
- blood is delivered to the tissues where it becomes deoxygenated
- blood re-enters the heart through the right atrium and fills the cavum pulmonale
- deoxygenated blood is pumped into the lungs, where it becomes oxygenated again
- oxygenated blood enters the heart through the left atrium and fills the cavum arteriosum, then cavum venosum
crocodile heart (4)
- chambers
- separation
- myocardium
- unique structures
- four-chambered heart, similar to birds and mammals
- complete separation of oxygenated and deoxygenated blood in the heart
- compact myocardium
- contain Foramen of Panizza and anastomosis
crocodile heart: foramen of panizza (3)
- connects blood exiting left ventricle to the blood exiting the right ventricle
- higher pressure from left ventricle causes blood from left ventricle to enter right aorta
- thought to be useful for diving to shut down blood flow to the lungs
crocodile heart: anastomosis (2)
- connects right and left aorta
- thought to even out volume between both sides of the systemic circulation
bird/mammal hearts (3)
- chambers
- separation
- myocardium
- four chambers
- complete separation of oxygenated and deoxygenated blood
- compact myocardium
bird/mammal hearts: chambers (2)
- two atria
- two ventricles
bird/mammal hearts: atria (2)
- thin-walled
- left receives oxygenated blood, right receives deoxygenated blood
bird/mammal hearts: ventricles (2)
- thick-walled
- completely separated by intraventricular septum
crocodile heart: ventricles
- ventricles completely separated by ventricular septum
bird/mammal hearts: valves (2)
- valves prevent flow reversal during contractions
- contain the atrioventricular (AV) valves and the semilunar valves
bird/mammal hearts: atrioventricular valves
- present between atria and ventricles
bird/mammal hearts: semilunar valves
- present between ventricles and arteries
why are bird and mammal hearts so divided (2)
- they are endotherms
- they must maintain heat and a high metabolic rate
