Lecture 10: Circulatory System Flashcards
what is included in the cs?
cardiovascular and lymphatic system
how does the cardiovascular system develop?
- heart from splanchnic mesoderm
- vessels and blood comprising of mesenchyme and mesodermal cells
what are erythrocytes? what do they do?
- red blood cells
- transport oxygen
what are leucocytes? what do they do?
- white blood cells
- resist infection and diseases
what are thrombocytes? what do they do?
- platelets
- initiate clotting
what do arteries do?
carry blood away from heart
what do veins do?
- carry blood to heart
- portal veins carry blood between organs
what are capillaries?
tiny vessels between arterioles and venules
what is the innermost layer of a vessel?
- tunica intima
- lining composed of epithelial cells
what is the middle layer of a vessel?
- tunica media
- contains smooth muscles
- connective tissue fibres allow expansion and recoil
what is the outermost layer of a vessel?
- tunica adventitia
- fibrous connective tissue
what does vasoconstriction do to vessels?
narrows vessels due to smooth muscle contraction
what does vasodilation do to vessels?
expands vessels due to blood pressure when smooth muscle relaxes
how does blood travel in fishes?
- single circulation
- heart > gills > body > heart
how does blood travel in birds and mammals?
- double circulation
- pulmonary circuit: heart > lungs > heart
- systemic circuit: heart > rest of body > heart
what are the haemodynamic patterns?
- pressure rises on ventricular contraction and drops in relaxation
- pressure declines with distance from heart
- one-way valves prevent retrograde flow
what is the function of the ventral aorta in fishes?
carries deoxygenated blood from heart to branchial region
describe the aortic arches in cyclostomes
8 in lampreys and 15 in hagfish
describe the aortic arches in gnathostomes
- mandibular (1) lost and hyoid (2) lost in some taxa
- 5 in chondricthyans
- 4 in actinopterygians
- 5 in lungfishes
describe the aortic arches in salamanders
- 1 and 2 lost
- 3-6 persist without gills
- 3-7 lost dorsal aorta
- 3: supplies carotid circulation of head
- 4 and 5: systemic circulation
- 6: supplies blood to pulmonary circulation
describe the aortic arches in frogs
- 3,4,6 persist in adults
- 5: carotid duct lost
- 3: supplies head
- 4: supplies body
-6: forms pulmonary circuit and cutaneous artery
describe the aortic arches in non-avian reptiles
- 1,2,5 lost
4: forms right and left systemic arches
3: provides cranial blood supply
6: forms single pulmonary arch to lungs
describe the role of heart
- pushes blood out into arteries
- receives blood from veins
what are the 4 chambers of the heart
- sinus venosus (first to receive blood)
- atrium
- ventricle
- bulbus cordis (leads to arteries
where does the heart derive from
splanchnic mesoderm
what is the fourth chamber referred to in other taxa?
- embryo: bulbus cordis
- lissamphibians/fish: conus arteriosus
- lamprey/teleosts: bulbus arteriosus
- absent in amniotes and hagfish
describe the hagfish heart
- 3 chambers
- no major nerves
- supplementary pumps occur in venous system
describe lamprey hearts
- 4 chambers
- semilunar valves present in lumen of 4th chamber
- no accessory hearts
describe gnathostome hearts
- 4 chambers
- s-shaped heart
describe chondrichtyan hearts
- 4 chambers
- multiple conal valves
describe teleost heart
- 4 chambers
- single bulbal valve at the entrance to bulbus arteriosus
describe lungfish heart
- partial double circulation
- atrium divided by interatrial septum
- pulmonary and systemic vein enters sinus venosus
describe lissamphibia heart
- 5 chambers: sinus venosus, conus arteriosus, right atrium, left atrium, and ventricle
