Circulation 3

Question 1

birds and mammals: heart structure (5)

Answer 1

• endothelium connective tissue which directly contacts blood
• endocardium
• myocardium
• coronary arteries
• pericardium consisting of: epicardium, pericardial fluid in pericardial cavity, and the parietal pericardium

Question 2

fish: heart structure (6)

Answer 2

• endocardium that covers the trabeculae
• spongy myocardium
• compact myocardium
• coronary arteries (only in very active fish)
• pericardial cavity
• pericardium

Question 3

which fish have coronary arteries and examples (2)

Answer 3

• very active fish; most don’t have coronary arteries
• eg. tuna and sharks

Question 4

vertebrate heart walls (4)

Answer 4

• pericardium
• epicardium
• myocardium
• endocardium

Question 5

vertebrate heart: pericardium (3)

Answer 5

• sac of connective tissue that surrounds the heart
• outer (parietal) and inner (visceral) layers
• space between the layers is filled with lubricating fluid

Question 6

vertebrate heart: epicardium (2)

Answer 6

• outer layer of heart, continuous with the visceral pericardium
• contain nerves that regulate heart and coronary arteries

Question 7

vertebrate heart: myocardium

Answer 7

• layer of heart muscle cells (cardiomyocytes)

Question 8

vertebrate heart: endocardium (2)

Answer 8

• innermost layer of connective tissue covered by epithelial cells (called endothelium)
• directly contacts the blood

Question 9

myocardium types (2)

Answer 9

• compact
• spongy

Question 10

compact myocardium (2)

Answer 10

• tightly packed cells arranged in regular pattern
• much more muscle than spongy myocardium (more compact), increasing the ability to do work to support metabolism

Question 11

spongy myocardium (3)

Answer 11

• 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

Question 12

myocardium: mammals

Answer 12

• mostly have compact myocardium

Question 13

myocardium: fish and amphibians (2)

Answer 13

• mostly have spongy myocardium, but active fishes can have more compact myocardium
• arranged as trabecular that extend into chambers

Question 14

why does oxygen needed to be supplied to the heart

Answer 14

• myocardium is extremely oxidative and has a high O2 demand

Question 15

how do mammals and birds obtain O2 to the heart

Answer 15

• coronary arteries supply oxygen to compact myocardium

Question 16

how do fish obtain O2 to the heart

Answer 16

• spongy myocardium obtains oxygen from blood flowing through the heart

Question 17

fish hearts (3)
- chambers
- separation
- myocardium

Answer 17

• four chambers arranged in series
• only deoxygenated blood passes through the heart
• spongy myocardium

Question 18

fish heart chambers (4)

Answer 18

• sinus venosus
• atrium
• ventricle
• bulbus arteriosus

Question 19

amphibian hearts (3)
- chambers
- separation
- myocardium

Answer 19

• three-chambered heart
• partial separation of oxygenated and deoxygenated blood; the beginning of separation in heart
• spongy myocardium

Question 20

amphibian heart: chambers (3)

Answer 20

• two atria
• one ventricle
• conus arteriosus

Question 21

amphibian heart: ventricle (2)

Answer 21

• trabecular in ventricle
• helps to prevent mixing of oxygenated and deoxygenated blood in the ventricle

Question 22

amphibian heart: right atrium (2)

Answer 22

• contains the sinus venosus
• receives deoxygenated blood

Question 23

amphibian heart: left atrium

Answer 23

• receives oxygenated blood from the pulmonary vein

Question 24

amphibian heart: conus arteriosus (2)

Answer 24

• contains a spiral fold
• helps direct deoxygenated blood to pulmocutaneous circuit and oxygenated blood to the systemic circuit

Question 25

circulatory pattern in amphibians (5)

Answer 25

- 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

Question 26

reptile hearts (3) - chambers - separation - myocardium

Answer 26

- five-chambered heart - separation of oxygenated and deoxygenate blood in ventricle is nearly complete - compact myocardium

Question 27

reptile heart: chambers (2)

Answer 27

- two atria - three interconnected ventricular compartments, which allow for good degree of blood separation

Question 28

reptile heart: interconnected ventricular compartments (3)

Answer 28

- cavum venosum - cavum pulmonale - cavum arteriosum

Question 29

reptile heart: cavum arteriosum

Answer 29

- receives blood from left atrium and leads to the cavum venosum

Question 30

reptile heart: cavum venosum

Answer 30

- leads to systemic aortas

Question 31

reptile heart: cavum pulmonale

Answer 31

- leads to pulmonary artery

Question 32

reptile heart: shunts (2)

Answer 32

- 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

Question 33

reptile heart: right-to-left shunt (2)

Answer 33

- deoxygenated blood bypasses pulmonary circuit and enters systemic circuit, bypassing the lungs - thought to be active during breath-holding

Question 34

reptile heart: left-to-right shunt (2)

Answer 34

- 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

Question 35

circulatory pattern in reptiles (5)

Answer 35

- 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

Question 36

crocodile heart (4) - chambers - separation - myocardium - unique structures

Answer 36

- 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

Question 37

crocodile heart: foramen of panizza (3)

Answer 37

- 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

Question 38

crocodile heart: ventricles

Answer 38

- ventricles completely separated by ventricular septum

Question 39

crocodile heart: anastomosis (2)

Answer 39

- connects right and left aorta - thought to even out volume between both sides of the systemic circulation

Question 40

bird/mammal hearts (3) - chambers - separation - myocardium

Answer 40

- four chambers - complete separation of oxygenated and deoxygenated blood - compact myocardium

Question 41

bird/mammal hearts: chambers (2)

Answer 41

- two atria - two ventricles

Question 42

bird/mammal hearts: atria (2)

Answer 42

- thin-walled - left receives oxygenated blood, right receives deoxygenated blood

Question 43

bird/mammal hearts: ventricles (2)

Answer 43

- thick-walled - completely separated by intraventricular septum

Question 44

bird/mammal hearts: valves (2)

Answer 44

- valves prevent flow reversal during contractions - contain the atrioventricular (AV) valves and the semilunar valves

Question 45

bird/mammal hearts: atrioventricular valves

Answer 45

- present between atria and ventricles

Question 46

bird/mammal hearts: semilunar valves

Answer 46

- present between ventricles and arteries

Question 47

why are bird and mammal hearts so divided (2)

Answer 47

- they are endotherms - they must maintain heat and a high metabolic rate