Circulatory System

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

4
(No Transcript)
5
(No Transcript)
6
Blood

• Leukocytes
• Function in immunity, antibody production
• Phagocytosis

7
(No Transcript)
8
Blood

• Platelets
• Clotting of blood

9
(No Transcript)
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

11
(No Transcript)
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

14
(No Transcript)
15
Heart

• Parietal pericardium part of pericardial sac
  that encloses the heart
• Visceral pericardium epicardium
• Pericardial cavity between parietal visceral
  pericardium

16
(No Transcript)
17
Gill Breathing Fish Heart

• Single circuit pump with 4 chambers
• Sinus venosus pacemaker (through reptiles)
• Atrium
• Ventricle
• Conus arteriosus (trunk)

18
(No Transcript)
19
(No Transcript)
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

21
(No Transcript)
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

23
(No Transcript)
24
(No Transcript)
25
Amniote heart

• More complete divisions of heart, 2 circuit heart
• Two atria, two ventricles

26
(No Transcript)
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

28
(No Transcript)
29
(No Transcript)
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?

32
(No Transcript)
33
(No Transcript)
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

37
(No Transcript)
38
Amniote heart

• Fate of conus arteriosus
• Three trunks in reptiles
• Two trunks in birds and mammals

39
(No Transcript)
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

42
(No Transcript)
43
Key Points

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