The circulatory system transports blood, nutrients, gases, hormones, and wastes throughout the body. It consists of the heart, blood vessels (arteries, veins, and capillaries), and blood. The heart pumps blood through two circuits - the pulmonary circulation and the systemic circulation. It has four chambers and uses valves to ensure one-way blood flow. The cardiovascular system is regulated by both intrinsic and neural factors. Diseases can occur if the circulatory system is not functioning properly.

1. The Circulatory SystemThe Circulatory System
(complete Info. Ppt)(complete Info. Ppt)
By- Dr. Armaan singhBy- Dr. Armaan singh

2. Interesting Facts
 The heart beat is strong enough to squirt blood 30 feet
 The longer a boy’s ring finger is, the less likely they are to have a
heart attack (according to one study)
 The human heart beats ~35 million times per year
 The heart pumps ~1,000,000 barrels of blood in a lifetime
 Most heart attacks occur between 8-9 a.m.

3. Interesting Facts
The blue whale has the largest heart – it
weighs ~ one ton
The hummingbird has a heart that beats
1000 times per minute
Your entire volume of blood goes through
your entire body once every minute
Humans have ~60,000 miles of blood
vessels in their bodies (more than twice the
circumference of the earth!)
Your heart beats 100,000 times and pumps
~2000 gallons of blood every day
Pig and baboon hearts have been
transplanted into humans

4. Cardiovascular System
 Heart, vessels, blood
 Function: transport gases,
nutrients, wastes, hormones

5. The Heart
 Size of a fist; less than a pound
 In thorax; flanked by lungs; rests on
diaphram
 Top: base
 Bottom: apex

6. Pericardium
 Double-layered sac covering
the heart
 Outer layer anchors heart in
chest
 Inner layer (epicardium)
attached to heart wall
 Lubricating fluid in pericardial
space (between layers)
reduces friction

7. Pericarditis
Decrease in fluid
causes layers to
cling & rub against
each other resulting
in pain & decreased
efficiency of heart

8. Pericardial Tamponade
 Bleeding into pericardial space
after chest trauma
 Excess blood restricts
expansion of heart during
pumping
 Causes shock or death if not
corrected

9. Heart Wall
3 layers:
 Epicardium: outer wall joined with pericardium
 Myocardium: the actual cardiac muscle that contracts
 Endocardium: lines heart chambers & vessels

10. Heart Chambers
Four chambers:
 2 atria: top of heart –
receive blood from veins
 2 ventricles: bottom of
heart – pump blood
through arteries

11. Heart Chambers
 Septum: divides left from
right heart
 Valves: keep blood flowing
in one direction
 Four valves:
 2 AV valves,
 2 semilunar valves
Heart sounds (Lupp-
dupp) from valves closing

12. Atrioventricular
Valves
AV valves: between atria
and ventricles
Bicuspid (mitral) valve:
on the left
Tricuspid valve: on the
right
When valves are open blood drains from atria
into ventricle
When ventricle contract, valve flaps are
forced shut, blocking blood from reentering

13. Semilunar Valves
 Located in arteries leaving
ventricles
 Pulmonic valve: at base of
pulmonary artery
 Aortic valve: at base of aorta
 When ventricles contract, valves are forced open & let blood flow
 When ventricle relaxes, backflow of blood fills flaps of valve & forces
them to shut

16. Blood Vessels
 Arteries: carry blood
away from the heart
 Veins: carry blood to
the heart
 Capillaries: connect
arteries to veins &
exchange gases with
tissues

17. Arteries
 Carry blood at high pressure
 Very thick, stretchy walls that expand
in size
 Most carry oxygenated blood (red)
 Damaged arteries spurt in time to
heart beat

18. Arteries
 Aorta: largest vessel
(diameter of a garden hose) –
receives blood from left
ventricle
 Arteriole: smaller vessels
connecting arteries to
capillaries

19. Veins
 Carry blood at low pressure
 Have valves to prevent backflow
of blood against gravity
 Most carry de-oxygenated blood
(purple)
 Damaged veins ooze blood

20. Veins
 Vena Cava: dump all blood from the
body into the right atria
 superior vena cava: receives blood
from upper body
 inferior vena cava: receives blood from
lower body
 Venules: smaller vessels connecting
veins to capillaries

22. Capillaries
Connect arteries and veins
Walls are one cell thick
Allow exchange of gases through thin walls
Drop off oxygen delivered from heart by arteries

23. How Blood Travels thru Vessels
heart artery arteriole capillary venule vein
heart

24. Atherosclerosis
Narrowing of
vessel lumen
due to
plaque/fat
formation on
inside of walls
Causes: diet
high in fat,
cholesterol, salt;
inactive
lifestyle;
smoking
Risks: high BP,
enlarged heart,
embolus
blocking

25. Coronary
Artery Disease
 When Atherosclerosis affects the arteries that supply the heart muscle
 Symptoms: short of breath after simple exertion, angina (chest pain)
 Risk: MI, cardiac arrest, death

26. How is CAD
treated?
 Medication
 Angioplasty (balloon surgery)
– balloon is inserted and
inflated in blocked vessel to
compress fatty mass against
the artery wall

27. How is CAD Treated?
Stent – wire mesh inserted into the artery to
expand its lumen
Coronary Artery Bypass – arteries are removed
from leg and grafted into the heart to restore
circulation

28. Vessel Disorders
Varicose Veins:
twisted, dilated veins
resulting from pooling of
blood due to long periods
of standing, obesity, or
inactivity

29. Vessel Disorders
Thrombophlebitis:
inflammation of a vessel due
to clot formation & poor
circulation. Clot can become
an embolus if freed.

30. Aneurysm
 Weaking in the wall of a vessel, causing it to balloon outwards.
 Rupture of the site causes
 Stroke (if in the brain)
 Death (in a large artery – aorta).

32. Cardiac
Circulation
 Coronary arteries exit the aorta & supply oxygen/blood to heart muscle
(myocardium)
 Coronary veins pick up & return deoxygenated blood from myocardium

33. Defects in
Coronary
Circulation
Angina Pectoris: impaired circulation to
myocardium causes oxygen deprivation & pain
Myocardial infarction: “heart attack” – blockage
of circulation to section of myocardium causes
the muscle to infarct (die)

34. Pulmonary Circulation
 Right ventricle pumps deoxygenated blood through pulmonary
artery to the lungs
 The blood picks up O2 from the lungs and dumps CO2 into the
lungs
 Oxygenated blood is returned to the left atrium thru the
pulmonary vein

37. Systemic
CirculationOxygenated
blood is pumped
from left
ventricle thru
aorta to the
body
Blood dumps
oxygen into
tissues and
picks up CO2
Deoxygenated
blood travels
from body to
vena cava to

42. The Circulation

45. Play the Game
Number the parts 1 – 17 (just write the correct order on a piece of
paper). Pass your paper to a classmate when you finish. We will grade
them as a class.

46. Congestive Heart Failure
 Heart is ‘worn out’ from hypertension, multiple MI, atherosclerosis, or
age
 Heart pumps too weakly to meet tissue needs
 If one side is weaker than the other, blood will back up in system

47. Congestive Heart Failure
 Left ventricle is failing:
 Pulmonary congestion
 Pulmonary edema (blood in lungs)
causes suffocation
 Right ventricle is failing:
 Peripheral congestion
 Edema in distal body parts (ankles,
feet)

48. Pulmonary
Edema
Pulmonary
edema (A);
normal lung
(B)

49. Peripheral Edema
Swelling of feet and ankles due to CHF

51. Conduction System of the Heart
Heart is under two types of control:
 Autonomic Nervous system
 Sympathetic: speeds up contractions
 Parasympathetic: the “brakes” that slows down contractions
 Intrinsic Conduction System
 Also called “nodal system”
 Heart determines its own rate of contractions

52. Intrinsic Conduction
System
 Nodes are heart tissue that
stimulate heart muscle to
depolarize (contract)
 Depolarization moves from base to apex
 Different areas of the heart have different nodes, each with a different
rate
 Node rate gets slower as it moves downwards
 Faster nodes will override slower nodes

54. Nodes (you need to know
these)

55. SA node fires, atria
contract (depolarize)
Impulse travels to AV
node, then travels
thru bundle of His,
bundle branches, &
Purkinje fibers –
ventricles contract
(depolarize)
Contraction of
ventricles has
‘wringing’ action,
pushing blood upward
and out through large
arteries

56. Parts of the
Conduction
System
SA node:
 “The Heart’s Pacemaker”
 In atria
 Normally sets the pace of 60 – 70
 SA can increase rate when stimulated by drugs, fever, or sympathetic
NS (exercise, stress, emotion)

57. AV Node:
 Between atria &
ventricles
 Special tissues transmit signal from SA to AV node
 Intrinsic rate: 40 - 60

58. Parts of the
Conduction
System
Bundle of His:
 Transmits impulse to
ventricles
 Rate: 30 – 40 beats/min
Bundle Branches:
 Within ventricular muscles
 Rate: 20 – 30 beats/min
Purkinje fibers:
 Terminal end of branches

59. What if Damage Occurs?
 If SA node is damaged or its signal is blocked, the AV
node takes over setting the pace (40-60/min)
 If AV node is next damaged, the bundles set the rate
(20 – 40/min)

60. What is a Pacemaker?
If heart is unable to generate
impulse, or pace is too slow,
mechanical pacemaker is
surgically implanted to
provide artificial impulses

61. Electrocardiogra
m (ECG/EKG)
 Electrical impulses in heart
are measured with ECG
 Electrical activity is
translated into waves

62. Electrocardiogram (ECG/EKG)
 P Wave: atria depolarize
 QRS complex: ventricles
depolarize
 T wave: repolarization

63. Abnormalities in
ECG
 Heart Monitor hooked up with pads on chest
 Abnormalities in ECG used to diagnose heart damage
 Diagnostic signs: changes in shape of wave, distance between waves,
lack of waves…

64. Irregular Heart Rhythms
 Tachycardia: heart is beating too fast
 Bradycardia: heart is beating too slow
 Heart Block: no connection between atria & ventricles – ventricles
beat at their own rate
 Ventricular Fibrillation: heart is ‘shivering’ – no contractions or pulse
(cardiac arrest)
 Asystole: dead heart – no electrical activity

65. Comparing Rates
 Normal Sinus Rhythm
 Sinus Bradycardia
 Sinus Tachycardia

66.  Elevated ST segment (sign of a MI)
 Ventricular Tachycardia
 Heart Block

67.  PVC (premature ventricular fibrillation)
 Ventricular Fibrillation
 Asystole

69. Cardiac Cycle
Cardiac Cycle: The events
within one heartbeat. Three
main stages:
Mid-to-late diastole: SL
valves are closed, AV open;
atria contract; blood is forced
into ventricles
Ventricular systole:
ventricular pressure forces AV
closed; SL forced open; blood
rushes out of ventricles; atria
relax & refill
Early diastole: SL shut; AV

70. Heart Sounds
 Cardiac cycle heard with a stethoscope
 Two sounds: “lub dup” (pause) “lub dup” (pause) …..
 Lub = closing of AV valves (ventricular systole)
 Dup = Closing of semilunar valves (between ventricular systole &
diastole)
 Murmurs: abnormal heart sounds that usually indicate valve
problems

71. Valve Disorders
 Leaky Valves: caused by
incompetent or deformed
valves that force the heart to
re-pump blood because of
backflow

72. Stenosis
Valves are stiff and do not open completely. Heart has to pump harderMurmur: stenosis

73. Mitral Valve Prolapse
 The most common
valve disorder
(5-10% of people)
 Mitral valve opens
(prolapses) into atrium
when shutting & allows
blood backflow

74. Cardiac Output
 Cardiac Output: the amount of blood pumped by each
side of the heart per minute
 Cardiac output = heart rate X stroke volume
 Stroke volume = the amount of blood pumped with each
contraction

75. What is the cardiac output if….
HR = 75 bpm; SV = 70 ml/beat?
This is the normal cardiac output for a resting adult.
How is the output affected with exercise?
Do you think it increases or decreases?

76. What affects Stroke Volume?
(you don’t have to write this down)
Increase in Stroke volume:
 Increased venous blood return
 exercise (muscles force blood into heart)
 Slow hr (more time to fill ventricles)
Decrease in stroke volume
 Decreased venous return
 Hemorrhage (less blood volume)
 Tachycardia (not enough time to fill)

77. What affects Heart Rate?
(you don’t have to write this either)
Increase:
 Decline in SV (heart
compensates by hr)
 Babies and kids
 Females
 During exercise
 Sympathetic NS
Decrease:
 Parasympathetic NS
 Getting older
 Males
 Being fit (heart is more
efficient)
 Cold temperatures

78. Taken to assess overall health status
 Arterial pulse
 Blood Pressure
 Respiratory Rate
 Temperature

79. Arterial Pulse
 Alternating expansion and recoil
of arteries with each heart beat
 Measured in beats per minute
 Normal resting pulse: 60 – 100
bpm
 Taken at pulse points: place
where pulse is easily palpated
(felt)

80. Pulse Points
Can also be used as
pressure points to stop
bleeding

81. Blood Pressure
Pressure of the blood against artery walls
Measured as systolic/diastolic (ex. 120/80)
Systolic: pressure at peak of contraction
Diastolic: pressure during ventricular relaxation
Can be taken by:
Auscultation (listening for pulse)
Palpation (feeling for pulse)
Normal: 100 + age / 60-90

82. What Determines
the BP?
 Cardiac Output (blood pumped per min)
 Peripheral Resistance
 friction inside vessel that hampers flow of blood
 Usually results from narrowing of arteries

83. What affects BP
Increases BP:
 Atherosclerosis
 Thick blood
 Drugs/nicotine
 Obesity
Decreases BP:
 Shock/blood loss
 MI
 Drugs
 Physical fitness

84. Problems with BP
 Hypotension (low BP):
 Systolic < 90mm/Hg
 Cause: MI; warning sign of shock; athletes
 Hypertension (high BP)
 Systolic >140; Diastolic >90
 Heart is forced to work hard for extended time
 Vessels damaged due to higher pressure
 Causes: obesity, diet, exercise, smoking, genes
 Risks: heart attack, stroke