The document provides detailed information about heart anatomy and physiology. It describes the heart's layers (endocardium, myocardium, epicardium), chambers (right and left atria and ventricles), valves (atrioventricular and semilunar), blood vessels (vena cava, pulmonary artery/veins, aorta), and conduction system (SA node, AV node). It also explains cardiac cycle, blood pressure, EKG readings, and the differences between arteries, veins, and capillaries. Factors influencing blood pressure and methods for lowering high blood pressure are also summarized.

1. Thoracic Mediastinum
Pleural
Pericardial
We often put our hand over our heart. But where exactly is the
heart located. Look carefully at the diagram. What is the name
of the general cavity where the heart is located? What is the
more specific cavity where the heart is located?

3. The heart consists of 3 layers
• Endocardium- inside layer. Remember how the
endometrium lines the uterus? This layer is the
inner layer of the heart.
• Myocardium- the middle, muscular layer.
Remember how the myometrium was the
muscular layer of the uterus? The prefix “myo”
refers to muscle.
• Epicardium- Outer layer of the heart. Sometimes
called pericardium. Remember how “peri” means
“to cover”? Pericardium covers the “cardia”,
which refers to the “heart”.

5. The heart has 4 chambers. The upper chambers are the atrium. The lower chambers
are the ventricles.
An atrium is a smaller room you enter before you enter the building. In large stores it
is the space between the outside doors and the inside doors. The atrium of the heart
is the first chamber blood enter.
left
atrium
right
atrium
left
ventricle
right
ventricle

6. When identifying parts of the heart, remember that the “right”
and “left” refer to the heart owner’s right and left side!
Left atrium
Right atrium
Left ventricle
Right ventricle
Left hand
Right hand

7. Your heart is about
the size of your fist!

8. What are the major blood vessels around the heart?
Blood enters the right side of the heart via the VENA CAVA.
right
atrium
Superior vena cava
Inferior vena cava

9. Blood travels from the right atrium to the right ventricle.
Blood leaves the right side of the heart through the PULMONARY ARTERY.
This blood is heading toward the right and left lungs. “Pulmonary” refers to
lungs.
Right ventricle
Pulmonary artery

10. Blood returns to the heart from the lungs. The blood is now filled with oxygen.
Blood enters the left side of the heart through the PULMONARY VEINS.
Left atrium
Pulmonary veins

11. Blood leaves the left side of the heart through the AORTA. This
blood will be circulated around the body.
Left ventricle
Aorta

12. The heart needs blood too! It is cardiac muscle and is flexing constantly, so
the heart muscle needs lots of oxygen and glucose. The CORONARY blood
vessels supply the heart with blood.
.

13. The chambers of the heart keep oxygenated blood separated from
deoxygenated blood. The VALVES of the heart prevent blood from traveling
backwards. Blood circulates in one direction.
The VALVES between the chambers are called ATRIOVENTRICULAR valves.
These valves are between the atrium and the ventricles.
Left AV valve
Right AV valve

14. The valves that lead to blood vessels are names based on their
shape. They are called SEMILUNAR. Semilunar refers to looking
like a half moon shape. The rest of the name is the blood vessel
the valve leads to.
Aortic
semilunar
valve
Pulmonary semilunar
valve

15. Can you identify these parts of the heart?

16. Blood circulates through the heart and either goes to the body
systems and back or to the lungs and back.
Systemic circulation- body systems and back
Pulmonary circulation- lungs and back

17. The first exits from the AORTA are the coronary arteries, the
brachiocephalic, the left common carotid and the left subclavian
brachiocephalic
Left common carotid
Left subclavian
Brachiocephalic- blood travels to the
“brachio” region (upper arm) and the
“cephalic” region (head)
Common carotid- goes to the brain
Subclavian- goes under the clavicle
and to the upper arm

18. Don’t bug out! You’ve seen most of these already. Remember, everything on
the left side is also on the right side. The SEPTUM divides the lower
chambers of the heart.

19. Can you identify these parts of the heart?

20. What can you label on this heart?

21. Heart Anatomy Lists
• Right atrium
• Left ventricle
• Right A-V valve
• Aortic semilunar
• Vena cava
• Pulmonary artery
• Septum
• Left atrium
• Right ventricle
• Left A-V valve
• Pulmonary semilunar
• Aorta
• Pulmonary veins

22. Trace the path of blood through the heart. Which parts are
involved with systemic circulation? Which are involved with
pulmonary circulation?

23. The CARDIAC CYCLE refers to the contractions and relaxation of
the atriums and ventricles. When the atrium contract they are
in systole. When the atrium relax, they are in diastole. Both
atria contract at the same time.

24. When the ventricle contract they are in systole. When the
ventricles relax, they are in diastole. Both ventricles contract at
the same time. The strong contractions of the ventricles
increases the pressure of blood in the arteries.

25. The strong contractions of the ventricles sends blood out of the
heart. The amount of blood leaving the heart every minute is
called CARDIAC OUTPUT.
Calculate CO by multiplying the number of beats or heart rate,
by the the amount of blood that is pumped out. The amount of
blood pumped out is STROKE VOLUME.

27. Normally, CO= HR x SV. If a normal person has a HR of 75 and
pumps 70ml of SV. The result is pumping 5.25 liters of blood out
of one side of the heart every minute!
There are 3 things that regulate HR
1. Autonomic nervous system- increases or decreases HR
based on information from chemoreceptors or
baroreceptors.
2. Chemical regulation- hormones like EPI and NOR
3. Other factors- fitness, age, sex, and temperature

28. A normal adult HR is around 75 bpm. An infant may have a HR
of over 100! Typically, as people age their heartrate decreases.
A rapid heart rate of over 100 is TACHYCARDIA.
A relatively slow HR of under 60 is BRADYCARDIA.
Your maximum HR is 220 - your age. Your workouts should get
you HR to 75% of your maximum heartrate.

29. The autonomic nervous system signals the heart by the VAGUS
nerve. However, the heart can still beat outside of the body!
The heart has an intrinsic conduction system.
The SINOATRIAL NODE or SA node sends electrical impulses
around the atrium. The atrium contract. The SA node is called
the “pacemaker” It is located in the sinus of the right atrium.
The ATRIOVENTRICAL NODE or AV node sends an electrical
impulse down the septum and to the ventricles. The ventricles
contract. It is located between the atrium and the ventricles.

30. SA node starts the
electrical impulse
AV node makes the
ventricles contract

32. We cannot detect if the heart muscle is actually contracting, we
can read the electoral impulses.
The tool to read the electrical impulses is an ECG or EKG, both
are the same thing.
There are 3 waves in an EKG.
P wave- the atrium contract
T-wave- the
ventricles relax
QRS complex- the
ventricles contract

33. This is a 6 second ECG. Notice that there are 8 QRS complexes. We
can assume that the heart beats 8 times every 6 seconds. Using
some simple math we can estimate the HR.
6 x 10 = 60 s or 1 minute
8 x 10 = 80 beats per minute
Seconds QRS complex

34. There are a 3 other things to analyze on an ECG.
Rhythm- Are the QRS complexes equally spaced apart?
If so, the SA node is working properly. If not, the SA node is
not setting the pace of the heart.
QRS complex
T wave
P wave

35. Example of an irregular rhythm:

36. There are 2 other things to analyze on an ECG.
Hypertrophy: are the waves the right height?
If so, the muscle is contracting with the right amount of
force. If not, the muscle is working too hard.
QRS complex

37. Is the muscle working too hard?
Here is an example of an elevated p wave:
Elevated P wave

38. There is one last thing to look for on an ECG.
Blocks: are the waves the right length. If the impulse is
blocked it takes longer to get around the muscle. Look for a
wave that is longer than it should be.
QRS complex
T wave
P wave

39. Here is an example of third-degree heart block:
Elongated QRS complex

40. Blood that leaves the heart travels through ARTERIES. Blood
that enters the heart enters through VEINS.
Arteries are elastic, thick walled, muscular, and carry blood
AWAY from the heart. Arteries= away.
Veins have valves, a large lumen, and carry blood toward the
heart. Veins = valves.
Capillaries are the super small network of blood vessels where
blood drops off oxygen and nutrients, while picking up carbon
dioxide and wastes.

41. 1. How many layers are in each blood vessel?
2. Can you identify 2 differences between the blood vessels?

42. When the ventricles contract, blood leaves heart. This blood
travels through the arteries and is exerting high pressure.
Normal blood pressure is 120/80. The 120 refers to the
expanding arteries when the ventricles contract. The 80 refers
to the lower pressure of blood flow when the ventricles are in
diastole (relaxing). The 120 is the systolic pressure. The 80 is
the diastolic pressure.
Arteries are high pressure blood vessels. The elastic layer allows
the arteries to stretch during systole. The reason veins have
valves is because of the low pressure blood flow. The valves
prevent blood from flowing backwards.

43. There are several factors that can influence blood pressure.
1. Baroreceptors- baroreceptors detect pressure in the blood
vessels and send that feedback to the hypothalamus. Think
“barometers” reading atmospheric pressure.
2. Chemoreceptors detect oxygen, CO2, and H+ levels.
Chemical imbalances may cause and increase or decrease in
HR.
EX: Increases in HR or CO can increase BP
3. Hormones like EPI or NOR or ADH all influence blood
pressure.
EX: ADH increases blood volume, which increases blood
pressure.

44. There are several factors that can influence blood pressure.
4. Chemicals like vasoconstrictors will narrow blood vessels.
Nicotine is an example.
EX: Vasodilators will open blood vessels. Increased diameter
decreases blood pressure.
5. Temperature or physical changes like cooling or heating can
also change blood pressure.
6. Blood viscosity- the thicker the blood, the higher the
pressure
7. Vessel length- longer blood vessels create more resistance
and higher pressure.
EX: if a person gains 10lbs, their blood vessels get longer

45. How to fix high BP?
• Lower sodium. This lowers blood volume and
blood pressure
• Stop smoking. Less nicotine means blood vessels
dilate and less blood pressure
• Lose weight. Less weight means shorter blood
vessels and less pressure
• More vegetables. More vegetables decreases
cholesterol levels, unclogging arteries. Less
restriction means less blood pressure
• Exercise. Strengthening the heart means more
cardiac output for a lower heartrate.