1. The Circulatory System

2. Blood Type of connective tissue composed
Fluid matrix called plasma
Formed elements
Functions of circulating blood
Transportation
Regulation
Protection

3. Plasma
(92% water, 55%
of whole blood)
Red blood
cells
Plasma
Platelets and
leukocytes (<1%)
Formed
elements
Red blood cells
(erythrocytes)
(45% of whole
blood)
Platelets
White blood cells
Blood Plasma
Red Blood Cells
Platelets
Plasma proteins (7%)
Albumin (54%)
Globulins (38%)
Fibrinogen (7%)
All others (1%)
4 million–6 million/
mm3 blood
150,000–300,000/
mm3 blood
Water (91.5%)
Other solutes (1.5%)
Neutrophils
Eosinophils
Electrolytes
Nutrients
Gases
Regulatory
substances
Waste products
60–70%
2–4%
Monocytes
Basophils
Lymphocytes
3–8%
0.5–1%
20–25%

4. Blood plasma 92% water Contains the following solutes
Nutrients, wastes, and hormones
Ions
Na+, Cl–, HCO3, and trace Ca2+, Mg2+, Cu2+, K+, Zn2+
Proteins
Albumin (produced in liver, helps maintain osmotic pressure in blood)
Fibrinogen (aids in formation of clots)
If fibrinogen is removed, plasma is called serum

5. Formed elements Red blood cells (erythrocytes)
About 5 million per microliter of blood
Hematocrit is the fraction of the total blood volume occupied by red blood cells
Mature mammalian erythrocytes lack nuclei
RBCs of vertebrates contain hemoglobin
Pigment that binds and transports oxygen

6. Formed elements White blood cells (leukocytes)
Less than 1% of blood cells
Larger than erythrocytes and have nuclei
Can migrate out of capillaries into tissue fluid

7. Formed elements Platelets
Cell fragments that pinch off from larger cells in the bone marrow
Function in the formation of blood clots
Prothrombin
Thrombin
Fibrinogen
Thrombin
Fibrin
3. Cascade of enzymatic
reactions is triggered
by platelets, plasma
factors, and
damaged tissue.
1. Vessel is damaged,
exposing surrounding
tissue to blood.
2. Platelets adhere
and become sticky,
forming a plug.
4. Threads of fibrin trap
erythrocytes and form
a clot.
5. Once tissue damage
is healed, the clot is
dissolved.

8. Formed elements All develop from stem cells
Blood cell production occurs in the bone marrow

9. Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pluripotent Stem Cell
Myeloid stem line
Lymphoid stem line
Myeloid Stem Cell
Lymphoid Stem Cell
Progenitor cell
Progenitor cell
Progenitor cell
B lymphoblast
Tlymphoblast
Proerythroblast
Megakaryoblast
Myeloblast
Monoblast
Early erythroblast
Promegakaryocyte
Monocyte
Eosinophil
Basophil
Neutrophil
B lymphocyte
Tlymphocyte
Late
erythroblast
Normoblast
Megakaryocyte
Nucleus
ejected
Reticulocyte
Erythrocyte
Platelets

10. Vertebrate Circulatory Systems
Mammals, birds, and crocodilians
4-chambered heart
2 separate atria and 2 separate ventricles
Right atrium receives deoxygenated blood from the body and delivers it to the right ventricle, which pumps it to the lungs
Left atrium receives oxygenated blood from the lungs and delivers it to the left ventricle, which pumps it to rest of the body

11. The heart and circulation of mammals and birds
Head
Systemic
capillaries
Aorta
Lungs
Pulmonary
artery
Superior
vena cava
Respiratory
capillaries
Pulmonary
artery
Pulmonary
vein
Pulmonary
veins
Aorta
Superior
vena cava
Left atrium
Pulmonary
semilunar valve
Bicuspid
mitral
valve
Right atrium
Inferior
vena cava
Artery
Tricuspid valve
Left
ventricle
Right ventricle
Body
Inferior
vena cava
Systemic
capillaries
The heart and circulation of mammals and birds

12. The Cardiac Cycle Heart has two pairs of valves
Atrioventricular (AV) valves
Maintain unidirectional blood flow between atria and ventricles
Tricuspid valve = On the right
Bicuspid, or mitral, valve = On the left
Semilunar valves
Ensure one-way flow out of the ventricles to the arterial systems
Pulmonary valve located at the exit of the right ventricle
Aortic valve located at the exit of the left ventricle

13. The Cardiac Cycle
Valves open and close as the heart goes through the cardiac cycle
Ventricles relaxed and filling (diastole)
Ventricles contracted and pumping (systole)
“Lub-dub” sounds heard with stethoscope
Lub – AV valves closing
Dub – closing of semilunar valves

14. Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100
Pressure (mm Hg) 75
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

15. atrioventricular (AV) valves close, and pressure in the
Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100
pressure in
left ventricle
Pressure (mm Hg) 75
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

16. atrioventricular (AV) valves close, and pressure in the
Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100
pressure in
left ventricle 1.
Pressure (mm Hg) 75
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

17. atrioventricular (AV) valves close, and pressure in the
Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100 2.
pressure in
left ventricle 1.
Pressure (mm Hg) 75
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

18. atrioventricular (AV) valves close, and pressure in the
Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100 2.
pressure in
left ventricle 1.
Pressure (mm Hg) 75 3.
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

19. atrioventricular (AV) valves close, and pressure in the
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100 2.
pressure in
left ventricle 1. 4.
Pressure (mm Hg) 75 3.
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

20. atrioventricular (AV) valves close, and pressure in the
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100 2.
pressure in
left ventricle 1. 4.
Pressure (mm Hg) 75 5. 3.
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

21. atrioventricular (AV) valves close, and pressure in the
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100 2.
pressure in
left ventricle 1. 4.
Pressure (mm Hg) 75 5.
pressure
in aorta 3.
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

22. atrioventricular (AV) valves close, and pressure in the
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonary
valve
Aortic
valve
Right
atrium
Left
atrium AV
valves
Left
ventricle
Right ventricle
1. The atria contract.
2. “Lub”: The ventricles
contract, the
atrioventricular (AV)
valves close, and
pressure in the
ventricles builds
up until the aortic
and pulmonary
valves open.
3. Blood is pumped out
of ventricles and
into the aorta and
pulmonary artery.
4. “Dup”: The ventricles
relax, the pressure in
the ventricles falls at
the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
5. The ventricles fill
with blood.
Diastole
Systole
Diastole
125
130 mL
100 1. 2.
pressure in
left ventricle 4. 75
volume in
left ventricle
Pressure (mm Hg) 5.
pressure
in aorta 3.
“Lub”
“Dup” 50 25
65 mL
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Time (seconds)

23. The Cardiac Cycle Heart contains “self-excitable” autorhythmic fibers
Most important is the sinoatrial (SA) node
Located in wall of right atrium
Acts as pacemaker
Autonomic nervous system can modulate rate

24. The Cardiac Cycle Each SA depolarization transmitted
To left atrium
To right atrium and atrioventricular (AV) node
AV node is only pathway for conduction to ventricles
Spreads through atrioventricular bundle
Purkinje fibers
Directly stimulate the myocardial cells of both ventricles to contract

25. The Cardiac Cycle
Electrical activity can be recorded on an electrocardiogram (ECG or EKG)
First peak (P) is produced by depolarization of atria (atrial systole)
Second, larger peak (QRS) is produced by ventricular depolarization (ventricular systole)
Last peak (T) is produced by repolarization of ventricles (ventricular diastole)

26. 1. The impulse begins at the SA node and travels to the AV node.
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Right atrium
Left atrium
SA node
(pacemaker)
Internodal
pathway
AV node AV
Interventricular
septum
AV bundle
AV bundle
Purkinje fibers
Purkinje fibers
Left and right
bundle branches
1. The impulse begins at the SA node and travels to the
AV node.
2. The impulse is delayed at the AV node. It
then travels to the AV bundle. R +1
P wave
T wave
Millivotts Q S
1 sec -1
Seconds

27. Interventricular septum Left and right bundle branches
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AV bundle
Interventricular
septum
Left and right
bundle branches
Purkinje fibers
3. From the AV bundle, the impulse travels
down the interventricular septum.
4. The impulse spreads to branches from the
interventricular septum.
5. Finally reaching the Purkinje fibers, the impulse
is distributed throughout the ventricles. R +1
P wave
T wave
Millivotts Q S
1 sec -1
Seconds

28. The Cardiac Cycle
Right and left pulmonary arteries deliver oxygen-depleted blood from the right ventricle to the right and left lungs
Pulmonary veins return oxygenated blood from the lungs to the left atrium of the heart

29. The Cardiac Cycle
Aorta and all its branches are systemic arteries, carrying oxygen-rich blood from the left ventricle to all parts of the body
Coronary arteries supply oxygenated blood to the heart muscle
Blood from the body drains into the right atrium
Superior vena cava drains upper body
Inferior vena cava drains lower body

30. The Cardiac Cycle
Arterial blood pressure can be measured with a sphygmomanometer
Systolic pressure is the peak pressure at which ventricles are contracting
Diastolic pressure is the minimum pressure between heartbeats at which the ventricles are relaxed
Blood pressure is written as a ratio of systolic over diastolic pressure

31. Artery alternates closed/open
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Blood pressure gauge
100
150
100
150
100
150 50
200 50
200 50
200
250
250
250
Cuff
Stethoscope
1. Cuff pressure: 150 mm Hg
Artery closed
2. Cuff pressure: 120 mm Hg
Systolic pressure
3. Cuff pressure: 75 mm Hg
Diastolic pressure
150
150
150 C C O C O C O C O C O
120
120
120 O C 75 75 75
cuff pressure C
artery closed
blood pressure O
artery open
Artery always closed
“No sound”
Artery alternates closed/open
“Pulse sound”
Artery always open
“No sound”
Measurement of blood pressure

32. Characteristics of Blood Vessels
Blood leaves heart through the arteries
Arterioles are the finest, microscopic branches of the arterial tree
Blood from arterioles enters capillaries
Blood is collected into venules, which lead to larger vessels, veins
Veins carry blood back to heart

33. Characteristics of Blood Vessels
Arteries and veins are composed of four tissue layers
Endothelium, elastic fibers, smooth muscle, and connective tissue
Walls too thick for exchange of materials across the wall
Capillaries are composed of only a single layer of endothelial cells
Allow rapid exchange of gases and metabolites between blood and body cells

34. Characteristics of Blood Vessels
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Artery
Vein
Capillary
Capillary
Endothelium
Fenestrated
capillary
Elastic layer
Smooth muscle
Sinusoid
Connective tissue a. b. c.

35. Characteristics of Blood Vessels
Arteries and arterioles
Larger arteries contain more elastic fibers in their walls than other blood vessels
Recoil each time they receive blood from the heart
Contraction of the smooth muscle layer of the arterioles results in vasoconstriction
Greatly increases resistance and decreases flow
Chronic vasoconstriction can result in hypertension
Relaxation of the smooth muscle layer results in vasodilation
Decreasing resistance and increasing blood flow to an organ

36. Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Vasoconstriction
Epidermis
Air or water
Vasoconstriction and vasodilation are important means of regulating body heat in both ectotherms and endotherms
Arteriole
Precapillary
sphincter (contracted)
Decrease in heat
loss across epidermis
Capillary
Venule a.
Vasodilation
Precapillary
sphincter (relaxed)
Increase in heat
loss across epidermis b.

37. Characteristics of Blood Vessels
Capillaries
Every cell in the body is within 100 micrometers (μm) of a capillary
Although each capillary is very narrow, so many of them exist that the capillaries have the greatest total cross-sectional area of any other type of vessel
Slows blood flow to allow for exchange with extracellular fluid

38. Characteristics of Blood Vessels
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Blood flows
toward heart
Veins and venules
Thinner layer of smooth muscles than arteries
Venous pump helps return blood to heart
Skeletal muscle contractions and one-way venous valves
Vein
Open
valve
Contracting
skeletal
muscles
Valve
closed

39. The Lymphatic System
Significant amount of water and solutes in the blood plasma filter through the walls of the capillaries to form the interstitial (tissue) fluid
Most fluid leaves at the arteriole end of the capillary and returns at the venule end
Fluid that does not return to capillaries is returned to circulation by the lymphatic system

40. Relationship between blood, lymph, and interstitial fluid
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Arteriole
Lymphatic
capillary
Capillary bed
Venule
Interstitial
fluid
Relationship between blood, lymph, and interstitial fluid a.
Lymphatic
capillary
Excess interstitial fluid
becomes lymph
Interstitial
fluid
Blood
flow
Capillary
Filtration
Absorption
Arteriole
Venule
Blood pressure
Osmotic pressure
Net absorption due to
osmotic pressure
Pressure
Net filtration due to
blood pressure
Arteriole
Venule
Direction of blood flow b.

41. The Lymphatic System
Consists of lymphatic capillaries, lymphatic vessels, lymph nodes, and lymphatic organs (spleen and thymus)
Excess fluid in the tissues drains into blind-ended lymph capillaries
Lymph passes into progressively larger vessels with one-way valves
Eventually drains into subclavian veins

42. Cardiovascular Diseases
Leading cause of death in the United States
Atherosclerosis
Accumulation of fatty material within arteries
Impedes blood flow
Arteriosclerosis
Arterial hardening due to calcium deposition
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. b. c.
2000 mm
2500 mm
1000 mm
a-b: © Ed Reschke; c: © Dr. Gladden Willis/Visuals Unlimited.

43. Cardiovascular Diseases
Heart attacks (myocardial infarctions)
Main cause of cardiovascular deaths in U.S.
Insufficient supply of blood to heart
Angina pectoris (“chest pain”)
Warning sign that the blood supply to the heart is inadequate but is still sufficient to avoid myocardial cell death
Stroke
Interference with blood supply to the brain

44. Blood Flow and Blood Pressure
Autonomic nervous system modulates heart rhythm and force of contraction
Cardiac center of the medulla oblongata modulates heart rate
Norepinephrine, from sympathetic neurons, increases heart rate
Acetylcholine, from parasympathetic neurons, decreases heart rate

45. Blood Flow and Blood Pressure
Cardiac output is the volume of blood pumped by each ventricle per minute
Increases during exertion because of an increase in both heart rate and stroke volume
Arterial blood pressure (BP) depends on the cardiac output (CO) and the resistance (R) to blood flow in the vascular system
BP = CO x R

46. Blood Flow and Blood Pressure
Baroreceptor reflex
Negative feedback loop that responds to blood pressure changes
Baroreceptors detect changes in arterial blood pressure
If blood pressure decreases, the number of impulses to cardiac center is decreased
Ultimately resulting in blood pressure increase
If blood pressure increases, the number of impulses to cardiac center is increased
Ultimately resulting in blood pressure decrease

47. Blood Flow and Blood Pressure
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
( – )
Sensor
Integrating Center
Effector
Response
Baroreceptor senses
expansion of blood
vessels and high
blood pressure
Cardiac center of
medulla increases
frequency of
impulses
Decreases
sympathetic
Decreased heart rate,
stroke volume,
vasodilation
Effector
( + )
Increases
parasympathetic
Stimulus
( – )
Lowers blood pressure
Blood pressure
Negative feedback
( – )
Raises blood pressure
( + )
Sensor
Integrating Center
Effector
Response
Baroreceptor senses
contraction of blood
vessels and low
blood pressure
Cardiac center of
medulla sends
fewer impulses
Increases
sympathetic
Increased heart rate,
stroke volume,
vasoconstriction
Effector
( – )
Decreases
parasympathetic

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49. Blood Flow and Blood Pressure
Blood pressure increases with blood volume
Blood volume is regulated by four hormones
Antidiuretic hormone (ADH)
Aldosterone
Atrial natriuretic hormone
Nitric oxide (NO)