1. Biology, 9th ed, Sylvia Mader
Chapter 34
Circulatory Systems
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2. Outline Transport in Invertebrates Transport in Vertebrates
Open versus Closed Circulatory Systems
Transport in Vertebrates
Transport in Humans
Heartbeat
Vascular Pathways
Blood Pressure
Cardiovascular Disorders
Blood
Components
Clotting

3. Transport in Invertebrates
Small aquatic animals with no circulatory system
Sponges, cnidarians and flatworms – thin body walls
Each of their cells is exposed to water and can independently exchange gases and eliminate wastes
Roundworms and other pseudocoelomates
Use a fluid-filled body cavity as a means of transporting substances
Fluid-filled cavity can also act as a hydrostatic skeleton
Animals that have a rigid skeleton
May still rely on body fluids for the purpose of locomotion
Bivalves pump hemolymph into the foot for digging into mud

4. Circulatory System Transports oxygen and nutrients and wastes products
Two types of circulatory fluids:
Blood – is contained within blood vessels
Hemolymph – is a mixture of blood and tissue fluid; it flows into the body cavity called hemocoel; present in animals with an open circulatory system
Examples of organisms: molluscs and arthropods

5. Open vs. Closed Invertebrate Circulation
Open Circulatory System
Consists of blood vessels and open spaces
Heart pumps hemolymph via vessels into tissue spaces
Hemolymph will eventually drain back into heart when the heart relaxes through the ostia
Hemolymph in grasshopper is colorless because it doesn’t contain hemoglobin; oxygen taken to cells by air tubes called tracheae, as well as carbon dioxide

6. Open vs. Closed Invertebrate Circulation
Closed Circulatory System
Consists of heart and blood vessels only
Found in annelids, some molluscs
Heart pumps blood to blood vessels
Valves prevent backflow of blood
Gas exchange occurs at the capillary level. Gases and materials diffuse to and from nearby cells
Vessels return blood to heart without contact between blood and tissues

7. Open vs. Closed Circulatory Systems
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dorsal
aorta
tubular
heart
ostia
heart
dorsal
blood
vessel
ventral
blood
vessel
lateral
vessel
ostia
valve
pump
pump
hemolymph
hemocoel
a. Open circulatory system
b. Closed circulatory system

8. Transport in Vertebrates
All vertebrates have a closed circulatory system called a cardiovascular system
Vertebrate heart:
Atria of heart receive blood from general circulation
Ventricles of heart pump blood out through blood vessels

9. Animation
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10. Transport in Vertebrates
Types of blood vessels:
Arteries, capillaries, and veins
Arteries - Carry blood away from heart
Arterioles – smallest of the arteries lead to capillaries
Capillaries – 1 cell thick tissues that exchange materials with tissue fluid
Venules – smallest of the veins that lead to veins
Veins - Return blood to heart

11. Anatomy of a Capillary Bed
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artery
arteriole
O2-rich
blood flow
precapillary
sphincter
arteriovenous
shunt
venule
O2-poor
blood flow
vein

12. Transport in Vertebrates
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Outer layer
Middle layer
Inner layer
fibrous connective tissue
smooth
muscle
elastic
tissue
endothelium
a. Artery
endothelium
b. Capillary
Outer layer
Middle layer
Inner layer
fibrous connective tissue
smooth
muscle
elastic
tissue
endothelium
closed valve
c. Vein

13. Comparison of Circulatory Pathways
Fish - Blood flows in single loop
Single atrium and single ventricle

14. Comparison of Circulatory Pathways
Amphibians - Blood flows in double loop
Systemic circuit and pulmonary circuit
Two atria with a single ventricle

15. Comparison of Circulatory Pathways
Other vertebrates - Blood flows in a double loop
Heart divided by septum into separate sides

16. Comparison of Circulatory Circuits in Vertebrates
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pulmonary
capillaries
pulmonary
capillaries
gill capillaries
pulmonary
circuit
pulmonary
circuit
right
atrium
left
atrium
right
atrium
left
atrium
ventricle
heart
ventricle
right
ventricle
left
ventricle
atrium
heart
aorta
aorta
aorta
systemic
circuit
systemic
circuit
systemic
capillaries
systemic
capillaries
systemic
capillaries a. b. c.

17. Transport in Humans Human Heart Fist-sized Cone-shaped
Very muscular organ (cardiac fibers)
Lies within a membranous sac (the pericardium)

18. Human Heart: Gross Anatomy
Septum separates the heart into left & right sides
Each side has two chambers
Upper two chambers are the atria
Thin-walled
Receive blood from circulation
Lower two chambers are the ventricles
Thick-walled
Pump blood away from heart

19. Animation
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20. External Heart Anatomy
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lung
sternum
left subclavian artery
left common carotid artery
brachiocephalic artery
superior vena cava
aortic arch
aorta
left pulmonary artery
pulmonary trunk
left pulmonary veins
right pulmonary artery
right pulmonary veins b.
pericardium
heart
left atrium
left cardiac vein
right atrium
right coronary artery
left ventricle
right ventricle
Inferior vena cava
apex a.
b: © SIU/Visuals Unlimited

21. Internal View of the Heart
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left subclavian artery
left common carotid artery
cardiac
muscle cell
brachiocephalic artery
mitochondrion
superior vena cava
aorta
intercalated
disk
left pulmonary artery
pulmonary trunk
left pulmonary veins
right pulmonary artery
right pulmonary veins
semilunar valve
left atrium
right atrium
atrioventricular
(bicuspid) valve
gap junction
atrioventricular
(tricuspid) valve
chordae tendineae b.
papillary muscles
right ventricle
septum
left ventricle
inferior vena cava a.
b: © Dr. Don W. Fawcett/Visuals Unlimited;

22. Human Heart: Valves
Valves open and close to control blood flow through heart
Atrioventricular valves
Tricuspid valve between right atrium and ventricle
Bicuspid valve between left atrium and ventricle
Semilunar valves
Pulmonary semilunar valve between right ventricle and pulmonary trunk
Aortic semilunar valve between left ventricle and aorta

23. Transport in Humans Blood returning to heart from systemic circuit
Venae cavae return blood to the right atrium
Right atrium pumps blood through the tricuspid valve to right ventricle
Right ventricle pumps blood through the pulmonary semilunar valve to the pulmonary circuit
Blood returning to heart from pulmonary circuit
Enters left atrium
Left atrium pumps blood through the bicuspid valve to the left ventricle
Left ventricle pumps blood through the aortic semilunar valve to the systemic circuit
Oxygen-poor blood never mixes with oxygen-rich blood (in humans)

24. Heartbeat Systole - Contraction of heart chambers
Diastole - Relaxation of heart chambers
Cardiac cycle - Two-part pumping action that takes about a second
Blood collects in atria, the atria contract
Pushes blood through tricuspid and mitral valves into the resting lower ventricles
This phase (the longer of the two) is called diastole
Second part begins after the ventricles fill
Ventricles contract
This is called systole
After blood moves into the pulmonary artery and aorta, the ventricles relax

25. Animation
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26. Stages in the Cardiac Cycle
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semilunar
valves close
(“dub”)
aortic semilunar valve
bicuspid valve
pulmonary
vein
semilunar
valves
superior
vena cava
aorta
left
atrium
right
atrium
right
atrium
left
ventricle
inferior
vena cava c. a.
right
ventricle
pulmonary
vein d.
aorta
atrioventricular (AV)
valves close
(“lub”)
represents
contraction b.
d: © Biophoto Associates/Photo Researchers, Inc.

27. Animation

28. Animation
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29. Heartbeat
The pulse is a wave effect passing down the walls of the arterial blood vessels when the aorta expands and recoils falling ventricular systole
Rhythmic contraction of the heart is due to the cardiac conduction system
Sinoatrial node (SA) keeps the heartbeat regular
Atrioventricular node (AV) signals ventricles to contract - Purkinje Fibers

30. Animation
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31. Animation
Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at

32. Conduction System of the Heart
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SA node T P
AV node Q
branches of
atrioventricular
bundle S
b. Normal ECG
Purkinje fibers a.
c. Ventricular fibrillation
d. Recording of an ECG
d: © David Joel/MacNeal Hospital/Getty Images

33. The Electrocardiogram
Electrocardiogram (ECG)
A recording of electrical changes that occur in the myocardium during cardiac cycle
When SA node triggers an impulse, the atrial fibers produce an electrical charge (P wave)
The P wave indicates that the atria are about to contract
The QRS complex signals that the ventricles are about to contract and the atria are relaxing
T wave is due to electrical changes occurring as the ventricular muscle fibers recover 33

34. Vascular Pathways
The human cardiovascular system includes two major circular pathways:
Pulmonary Circuit
Takes oxygen-poor blood to the lungs and returns oxygen-rich blood to the heart
Systemic Circuit
Takes oxygen-rich blood from the heart to tissues throughout the body and returns oxygen-poor blood to the heart through the venae cavae

35. Path of Blood CO2 head and arms O2 jugular vein (also subclavian
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CO2
head and arms O2
jugular vein
(also subclavian
vein from arms)
carotid artery
(also subclavian
artery to arms)
CO2 O2 O2
CO2
pulmonary
artery
lungs
pulmonary
vein
superior
vena cava
aorta
heart
inferior
vena cava
hepatic
vein
mesenteric
arteries
hepatic
portal
vein
liver
digestive
tract
renal
artery
renal
vein
kidneys
Iliac vein
iliac
artery
CO2 O2
trunk and legs

36. Blood Pressure
Contraction of the heart supplies pressure that keeps blood moving in the arteries
Systolic Pressure results from blood forced into the arteries during ventricular systole
Diastolic Pressure is the pressure in the arteries during ventricular diastole
Blood pressure
Normally measured with a sphygmomanometer on the brachial artery
Expressed in the form: Systolic “over” Diastolic

37. Blood Pressure
In arteries, the pressure of the blood forces it to move forward
Blood pressure falls as blood flows from the aorta into arteries and arterioles
Blood flow in the capillaries is slow
Blood pressure in the veins is too low to move blood back to the heart
Skeletal muscle contraction pushes blood in the veins toward the heart
Veins have valves to prevent backward flow of blood
A respiratory pump reduces pressure in the thoracic cavity to cause blood to move from the abdominal acvity into the thoracic cavity 37

38. Velocity and Blood Pressure
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ariteries
ariterioles
capillaries
venules
veins
total
cross-sectional
area of
vessels
blood
pressure
velocity
Magnitude
Blood Flow

39. Animation
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40. Cross Section of a Valve in a Vein
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
to heart
to heart
a. Contracted skeletal muscle
pushes blood past open valve.
b. Closed valve prevents
backward flow of blood.

41. Animation
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42. Cardiovascular Disorders
Hypertension - High blood pressure
Atherosclerosis - Accumulation of fatty materials between the inner linings of arteries
Stroke - Cranial arteriole bursts or is blocked by an embolus
Heart attack (myocardial infarction) – Coronary artery becomes completely blocked
Angina pectoris – Painful squeezing sensation from myocardial oxygen insufficiency due to partial blockage of a coronary artery

43. Coronary Arteries and Plaque
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coronary artery
ulceration
lumen of vessel
fat
atherosclerotic
plaque
cholesterol
crystals
© Biophoto Associates/Photo Researchers, Inc.

44. Blood: Homeostasis Functions
Transports substances to and from capillaries for exchange with tissue fluid
Helps destroy pathogenic microorganisms
Distributes antibodies
Maintains water balance and pH
Regulates body temperature
Carries platelets and factors to promote clotting and prevent blood loss

45. Maintain blood osmotic pressure and pH
Composition of Blood
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Plasma
Formed Elements
55%
Type
Function
Type
Number (per mm 3 blood)
Water
(90–92% of
plasma)
Maintains blood volume;
transports molecules
Red blood cells
(erythrocytes)
Transport O2 and help
transport CO2
Plasma proteins
(7–8% of plasma)
Maintain blood osmotic pressure and pH
45%
4 million–6 million
Globulins
Fibrinogen
Transport; fight infection
Blood clotting
White blood cells
(leukocytes)
5,000–1 1,000
Fight infection
Neutrophils
Lymphocytes
Salts
(less than 1% of
plasma)
Maintain blood osmotic pressure and pH;
aid metabolism
40–70%
20–45%
Monocytes
Eosinophils
Basophils
Gases
(O2and CO2)
Cellular respiration
Nutrients
(lipids, glucose,
and amino acids)
Food for cells
4–8%
1–4%
0–1%
Platelets
(thrombocytes)
Aid clotting
Wastes
(urea and
uric acid)
End product of metabolism;
excretion by kidneys
Hormones
Aid metabolism
150,000–300,000

46. Red Blood Cells Small, biconcave disks
Lack a nucleus and contain hemoglobin
Hemoglobin contains
Four globin protein chains
Each associated with an iron-containing heme
Manufactured continuously in bone marrow of skull, ribs, vertebrae, and ends of long bones

47. White Blood Cells Most types larger are than red blood cells
Contain a nucleus and lack hemoglobin
Important in inflammatory response
Neutrophils enter tissue fluid and phagocytize foreign material
Lymphocytes
T Cells attack infected cells
B cells produce antibodies in response to antigens

48. Animation
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49. Platelets Platelets A blood clot consists of:
Result from fragmentation of megakaryocytes
Involved in coagulation
A blood clot consists of:
Red blood cells
Fibrin threads

50. 1. Blood vessel is punctured.
Blood Clotting
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red
blood cell
fibrin
threads
platelet plug
fibrin threads
2. Platelets congregate and
form a plug.
3. Fibrin threads form and
trap red blood cells.
1. Blood vessel is punctured.
© Eye of Science/Photo Researchers, Inc.

51. Capillary Exchange
Capillaries are very narrow – Tiny RBCs must go through single file
Walls of capillaries are very thin to facilitate diffusion of nutrients, gases, and wastes
Water exits a capillary near the arterial end
Water enters a capillary near the venous end
Solutes diffuse into and out of a capillary according to their concentration gradient
Oxygen and nutrients diffuse out of capillaries
Carbon dioxide and wastes diffuse into the capillary

52. Capillary Exchange from heart to heart Tissue fluid oxygen amino acids
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from heart
to heart
Arterial end
Blood pressure is higher
than osmotic pressure.
Net pressure out.
Venous end
Osmotic pressure is higher
than blood pressure.
Net pressure in.
Tissue fluid
oxygen
amino
acids
carbon
dioxide
glucose
water
wastes
water
salt
plasma
protein
smooth
muscle fiber
osmotic pressure
venule
arteriole
blood pressure

53. precapillary sphincters
Capillary Bed
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precapillary sphincters
lymphatic capillary
excess tissue fluid
arteriole
tissue fluid
blood capillary
lymphatic duct
venule

54. Blood Types Determined by the presence or absence of surface antigens
ABO System
Rh System
Antibodies in the plasma can cause agglutination
Cross-reactions occur when antigens meet antibodies

55. Blood Type

56. No Agglutination 500× antigen Type A blood of donor no binding
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500×
antigen
Type A blood
of donor
no binding
red blood cell
anti-B antibody of
type A recipient
no clumping
No agglutination

57. Agglutination 500× antigen Type A blood of donor binding
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500×
antigen
Type A blood
of donor
binding
anti- A antibody of
type B recipient
clumping
Agglutination

58. Blood Type
During pregnancy, if the mother is Rh negative and the father is Rh positive, the child may be Rh positive.
Rh-positive red blood cells may leak across the placenta
The mother will produce anti-Rh antibodies.
Antibodies may attack the embryo in a subsequent pregnancy

59. Review Transport in Invertebrates Transport in Vertebrates
Open versus Closed Circulatory Systems
Transport in Vertebrates
Transport in Humans
Heartbeat
Vascular Pathways
Blood Pressure
Cardiovascular Disorders
Blood
Components
Clotting

60. Biology, 9th ed, Sylvia Mader
Chapter 34
Circulatory Systems
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Leukemia
SEM 5,270×
(Normal): © Yorgos Nikas/Getty Images; (Leukemia): © SPL/Photo Researchers, Inc.