1. Chapter 5
Cardiovascular System:
Heart and Blood Vessels

2. Points to Ponder What are the functions of the cardiovascular system?
What is the anatomy of the heart and blood vessels (veins and arteries)?
How is the heart beat regulated?
What is blood pressure?
What are common cardiovascular diseases and how might you prevent them?

3. What is the cardiovascular system?
5.1 Overview of the cardiovascular system
What is the cardiovascular system?
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CO2 O2
Includes the heart and blood vessels
Brings nutrients to cells and helps get rid of wastes
Blood is refreshed in the lung, kidneys, intestine and liver
Lymphatic vessels help this system by collecting excess fluid surrounding tissues and return it to the cardiovascular system
Respiratory System
tissue cells
Cardiovascular System
food
kidneys
liver
Digestive System
Urinary System
indigestible
food residues (feces)
metabolic wastes
(urine)

4. What are the function of the cardiovascular system?
5.1 Overview of the cardiovascular system
What are the function of the cardiovascular system?
Generate blood pressure
Transport blood
Exchange of nutrients and wastes at the capillaries
Regulate blood flow as needed

5. What is the main pathway of blood in the body?
5.2 The types of blood vessels
What is the main pathway of blood in the body?
Heart – arteries – arterioles – capillaries - venules – veins – back to the heart…

6. Arteries and arterioles:
5.2 The types of blood vessels
Arteries and arterioles:
Carry blood away from the heart
Their walls have 3 layers:
Thin inner epithelium
Thick smooth muscle layer
Outer connective tissue
Arterioles are small arteries that regulate blood pressure

7. Capillaries: Microscopic vessels between arterioles and venules
5.2 The types of blood vessels and
5.6 Exchange at the capillaries
Capillaries:
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Microscopic vessels between arterioles and venules
Made of one layer of epithelial tissue
Form beds of vessels where exchange with body cells occurs
Combined large surface area
artery
connective
tissue
arteriole a.
precapillary
sphincter
blood
flow
elastic tissue
capillary bed
endothelium
arteriovenous
shunt v.
smooth muscle
valve
venule
blood
flow
vein
v = vein; a = artery
(left): © Ed Reschke; (right): © Biophoto Associates/Photo Researchers,Inc.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
arteriole
tissue
cells
lymphatic
capillary
blood
capillary
lymphatic
duct
venule

8. 5.2 The types of blood vessels
Veins and venules:
Venules are small veins that receive blood from the capillaries
Venule and vein walls have 3 layers:
Thin inner epithelium
Thick smooth muscle layer
Outer connective tissue
Veins carry blood toward the heart
Veins that carry blood against gravity have valves to keep blood flowing toward the heart

9. How can you tell the difference between an artery and vein?
5.2 The types of blood vessels
How can you tell the difference between an artery and vein?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
artery
connective
tissue
arteriole a.
precapillary
sphincter
blood
flow
capillary bed
elastic tissue
endothelium
arteriovenous
shunt v.
smooth muscle
valve
venule
blood
flow
vein
v = vein; a = artery
(left): © Ed Reschke; (right): © Biophoto Associates/Photo Researchers,Inc.

10. 5.3 The heart is a double pump
Anatomy of the heart
A large, muscular organ consisting of mostly cardiac tissue called the myocardium
It is surrounded by a sac called the pericardium
Consists of two sides, right and left, separated by a septum
Consists of 4 chambers: 2 atria and 2 ventricles
2 sets of valves: semilunar valves and atrioventricular valves (AV valves)
The valves give the resulting “lub” and “dup” sound of the heart

11. External anatomy of the heart
5.3 The heart is a double pump
External anatomy of the heart
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left subclavian artery
left common carotid artery
brachiocephalic artery
superior vena cava
aorta
left pulmonary artery
pulmonary trunk
left pulmonary veins
right pulmonary artery
right pulmonary veins
left atrium
left cardiac vein
right atrium
right coronary artery
left ventricle
right ventricle
left anterior descending
coronary artery
inferior vena cava
apex a.

12. Internal anatomy of the heart
5.3 The heart is a double pump
Internal anatomy of the heart
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
left subclavian artery
left common carotid artery
brachiocephalic artery
superior vena cava
aorta
left pulmonary artery
pulmonary trunk
left pulmonary veins
right pulmonary artery
right pulmonary veins
left atrium
left cardiac vein
right atrium
right coronary artery
left ventricle
right ventricle
left anterior descending
coronary artery
inferior vena cava
apex a.

13. What are the two cardiovascular pathways in the body?
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CO2 O2
Pulmonary circuit: the right side of the heart that brings blood from the body to the heart and the lungs
Systemic circuit: the left side of the heart that brings blood to the entire body to deliver nutrients and rid it of wastes
jugular vein
(also subclavian
vein from arms)
head and arms
carotid artery
(also subclavian
artery to arms)
CO2 O2 O2
CO2
lungs
pulmonary
artery
pulmonary
vein
superior
vena cava
aorta
heart
inferior
vena cava
hepatic
vein
intestinal
arteries
liver
digestive
tract
hepatic
portal
vein
renal
artery
renal
vein
kidneys
iliac vein
iliac
artery
CO2 O2
trunk and legs

14. How do the structure of the vessels and heart match their functions?
5.3 The heart is a double pump
How do the structure of the vessels and heart match their functions?
The left ventricle is much more muscular than the right ventricle because it must pump blood to the entire body
The arteries are more muscular than veins to withstand the higher pressure exerted on them
The veins have a thinner wall and a larger center to store blood

15. How does the heartbeat occur?
5.3 The heart is a double pump
How does the heartbeat occur?
During systole the atria contract together followed by the ventricles contracting together
This is followed by diastole, a rest phase, when the chambers relax
This cardiac cycle, heartbeat, on average occurs 70 times/minute

16. What is the cardiac cycle?
5.3 The heart is a double pump
What is the cardiac cycle?
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semilunar
valves close
(“dup”)
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”) b.
d: © BiophotoAssociates/Photo Researchers, Inc.

17. How is the heartbeat controlled?
5.3 The heart is a double pump
How is the heartbeat controlled?
Internal control:
The SA node in the right atrium initiates the heartbeat and causes the atria to contract
This impulse reaches the AV node, also in the right atrium, to send a signal down the AV bundle and Purkinje fibers that causes ventricular contraction
These impulses travel between gap junctions at intercalated disks
External control:
heartbeat is also controlled by a cardiac center in the brain and hormones such as epinephrine and norepinephrine

18. Visualizing the heartbeat
5.3 The heart is a double pump
Visualizing the heartbeat
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
SA node
AV node
branches of
atrioventricular
bundle
Purkinje fibers a.

19. What is an electrocardiogram (ECG)?
5.3 The heart is a double pump
What is an electrocardiogram (ECG)?
A record of the electrical changes in the heart muscle during a cardiac cycle
The atria produce an electrical current when stimulated by the SA node called the P wave
The contraction of the ventricles is the QRS complex
The recovery of the ventricles is called the T wave
Looking at these electrical changes allows doctors to detect abnormalities

20. How does a “normal” and “abnormal” ECG compare?
5.3 The heart is a double pump
How does a “normal” and “abnormal” ECG compare?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. R T P Q
SA node S
AV node
b. Normal ECG
branches of
atrioventricular
bundle
Purkinje fibers a.
b © Ed Reschke;

21. 5.4 Features of the cardiovascular system
What is blood pressure?
The pressure against a blood vessel wall, usually measured in an artery in the arm
The highest pressure is during blood ejection from the heart called the systolic pressure
The lowest pressure is the diastolic pressure when the ventricles relax
Average blood pressure is recorded at about 120/80 mmHg (systolic/diastolic)
Reminder: this is controlled by the arterioles
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
column of
mercury
indicating
pressure
in mm Hg
300
280
260
240
220
No sounds
(artery is
closed)
200
180
160
140
120
systole
Sounds heard
(artery is
opening
and closing)
100 80
diastole 60 40 20
No sounds
(artery is open)
inflatable rubber cuff
sounds are heard with
stethoscope
squeezable bulb inflates
cuff with air
air valve

22. How is blood pressure categorized?
5.4 Features of the cardiovascular system
How is blood pressure categorized?

23. Why should we care about cardiovascular disease?
5.7 Cardiovascular disorders
Why should we care about cardiovascular disease?
Cardiovascular disease (CVD) is the most common cause of death in the western world

24. Disorders of the blood vessels:
5.7 Cardiovascular disorders
Disorders of the blood vessels:
Hypertension/high blood pressure
Atherosclerosis
Stroke
Heart attack
Aneurysm

25. 5.7 Cardiovascular disorders
Hypertension
High blood pressure results when blood moves through vessels at a rate higher than normal often due to arterial plaque
140/90 mmHg is considered hypertension
A silent killer because there are few symptoms
Can lead to a heart attack, stroke or kidney failure

26. Atherosclerosis A build up of plaque in blood vessels
5.7 Cardiovascular disorders
Atherosclerosis
A build up of plaque in blood vessels
Plaque that is stationary is called a thrombus and an embolus when it detaches and can move to distant sites
Associated with a stroke, heart attack and aneurysm
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
normal artery
coronary artery
plaque
artery with plaque
(plaque): © Biophoto Associates/Photo Researchers, Inc.; (normal): © Ed Reschke

27. Stroke Also known as a cerebrovascular accident (CVA)
5.7 Cardiovascular disorders
Stroke
Also known as a cerebrovascular accident (CVA)
Usually occurs when a cranial artery is blocked or bursts
Part of the brain dies dues to lack of oxygen
Symptoms may occur including numbness of hands or face, difficulty speaking and inability to see in one eye

28. Heart attack Also known as a myocardial infarction (MI)
5.7 Cardiovascular disorders
Heart attack
Also known as a myocardial infarction (MI)
Part of the heart dies due to lack of oxygen
Can begin with angina pectoris, a pain that radiates down the left arm due to a blockage of a coronary artery

29. Aneurysm A ballooning of a blood vessel
5.7 Cardiovascular disorders
Aneurysm
A ballooning of a blood vessel
Atherosclerosis and hypertension can weaken a vessel and cause ballooning
The most commonly affected is the abdominal artery or the arteries leading to the brain

30. How are disorders of the blood vessels treated?
5.7 Cardiovascular disorders
How are disorders of the blood vessels treated?
Dissolving blood clots:
t-PA is a drug that dissolves clots
Treating clogged arteries:
Bypass surgery: usually a vein from the leg is taken and used to bypass a clogged artery
Stents: wire mesh cylinder inserted into a clogged artery to hold it open
Angioplasty: a tube with a balloon is inserted into the clogged area and the balloon is then inflated to open the vessel
A stent and angioplasty may be used in combination

31. Disorders of the heart and its treatment
5.7 Cardiovascular disorders
Disorders of the heart and its treatment
Disorders:
Heart failure is when the heart no longer pumps properly
Treatments:
Left ventricular assist device (LVAD)
Heart transplant either natural or artificial
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
replacement
heart
wireless
energy
transfer
system
external
wireless
driver
internal
controller
external
battery
pack
rechargable
internal
battery
Photograph of
artificial heart
Artificial heart inside body
(right): Courtesy of SynCardia Systems, Inc.

32. Bioethical Focus: Cardiovascular Disease Prevention
5.7 Cardiovascular disorders
Bioethical Focus: Cardiovascular Disease Prevention
Preventable risk factors include:
Use of tobacco products
Drug and alcohol abuse
Obesity and a sedentary lifestyle
Poor Diet
Stress
Poor dental hygiene