1. Circulatory System
Overall components are blood, blood vessels, and heart
Overall function is to transport nutrients, gases, hormones, waste, immunity, and temperature regulation

2. Circulatory System Ontogeny & Phylogeny
First system to be functional in development
Similar embryology in all vertebrates
Individual variation within species

3. Blood Plasma (serum is plasma minus clotting factors)
Formed Elements = Cells
Erythrocytes
Red Blood Cells
Have hemoglobin pigment to carry oxygen
Need iron for hemoglobin synthesis

6. Blood Leukocytes Function in immunity, antibody production
Phagocytosis

8. Blood
Platelets
Clotting of blood

10. Blood Hemopoiesis = Formation of blood cells
Sites in adult include liver, kidney, spleen and red bone marrow depending on class
Blood islands – located in wall of yolk sac is earliest site of hemopoiesis in vertebrates
Hemocytoblast = stem cell

12. Heart Develops early from splanchnic hypomere
Functional by 30 hours in chick (21 d incubation)
Functional by 4 weeks in humans (280 d gestation)

13. Heart Wall Endocardium – inner, smooth lining
Myocardium – striated cardiac m., intercalated discs
Epicardium – outermost layer

15. Heart
Parietal pericardium – part of pericardial sac that encloses the heart
Visceral pericardium = epicardium
Pericardial cavity – between parietal & visceral pericardium

17. Gill Breathing Fish Heart
Single circuit pump with 4 chambers
Sinus venosus – pacemaker (through reptiles)
Atrium
Ventricle
Conus arteriosus (trunk)

20. Gill breathing fish heart
AV valve – one way valve between atrium & ventricle to prevent backflow
Semilunar valve – one way valve between ventricle & conus arteriosus to prevent backflow

22. Lungfish & Amphibians Two circuit heart
Divisions to divide heart into oxygenated and deoxygenated sides
Interatrial septum (partial or complete)
Interventricular septum/Ventricular trabeculae – partial
Spiral valve – tries to divide conus arteriosus

25. Amniote heart More complete divisions of heart, 2 circuit heart
Two atria, two ventricles

27. Amniote Heart Sinus venosus is the pacemaker through reptiles
Sinus venosus becomes the sinoatrial node in birds & mammals which is the pacemaker & is located in the wall of the RA
Pacemaker sets the pace for all heartbeats

30. Amniote heart Interatrial septum is complete
Foramen ovale is an embyronic hole in interatrial septum
Auricle is an expansion of atria in mammals only
Interventricular septum is complete in most

31. Key Points
What do you suppose the function of the auricle is?

34. Key Points
Why would the foramen ovale be a necessary structure in the mammalian fetus?

35. Key Points
Summarize the difference between a single circuit and a double circuit pump.
What anatomical features support the heart being a double circuit pump?

36. Amniote heart AV valves are bicuspid & tricuspid in mammals
Semilunar valves between ventricles and trunks

38. Amniote heart Fate of conus arteriosus Three trunks in reptiles
Two trunks in birds and mammals

40. Key Points
The conus arteriosus becomes trunks. Are trunks arteries or veins?
Name the two trunks in birds and mammals.

41. Circulation between lungs and heart
Pre/Postcava RA RV
Pulmonary trunk – arteries
Lungs LA LV
Aorta
Systemic circulation

43. Key Points
Without looking, trace the blood flow from pre/post cavas through heart, to lungs, back to heart to aorta.