11/11/24 - Cardiac Physiology (Part 1) Lecture Questions

What are the three components of the Cardiovascular System?

1. Heart

2. Blood Vessels

3. Blood

Which side of the body is the heart located in?

What is the top part of the heart called?

Bottom part?

Left side

Top part is called the Base and the bottom part is called the Apex

Where is the Heart located at?

Located in the Thoracic Cavity behind the Ribs

What is the purpose of the Diaphragm’s location?

Separates the Thoracic Cavity from the Abdominal Cavity

What is the Pericardium?

Sac surrounding the heart

What layers make up the Pericardium?

(From outside to inside)

1. Fibrous Pericardium

2. Parietal Layer

3. Pericardial Cavity

4. Epicardium / Visceral Layer

(FrPaPE)

What layers make up the Serous Pericardium?

(From outside to inside)

1. Parietal Layer

2. Pericardial Cavity

3. Epicardium / Visceral Layer

(PPE)

What two layers of the heart are inside past the Pericardium?

(From outside to inside)

1. Myocardium

2. Endocardium

What are the four chambers of the Heart?

What are these chambers’ main functions?

Two Atrias and Two Ventricles

Atrias — receiving chambers

Ventricles — pumping chambers

What is the Myocardium?

What does it do?

Known as the Heart Muscle

Contracts when the heart beats

Where is the Papillary Muscle located?

Attached to the Chordae Tendineae

What is the main function of the Interventricular Septum?

Separates the two Ventricles and keeps the Deoxygenated Blood from the Oxygenated Blood

What is another name for the Chordae Tendineae?

Also called the “Heart Strings”

What is the main function of Intercalated Discs?

What are they composed of?

Holds adjacent Cardiac Muscle Cells together

Composed of Desmosomes

What is the general path of blood flow through the Cardiovascular System?

1. Start at the Right Atrium

2. Tricuspid Valve (Right AV Valve)

3. Right Ventricle

4. Pulmonary Semilunar Valve

5. Pulmonary Arteries

6. Pulmonary Arterioles

7. Pulmonary Capillaries (GAS EXCHANGE)

8. Pulmonary Venules

9. Pulmonary Veins

10. Left Atrium

11. Bicuspid Valve (Mitral / Left AV Valve)

12. Left Ventricle

13. Aortic Semilunar Valve

14. Aorta

15. Systemic Arteries

16. Systemic Arterioles

17. Systemic Capillaries (GAS EXCHANGE)

18. Systemic Venules

19. Systemic Veins

20. Inferior / Superior Venae Cavae

*Bold = Oxygenated Blood, Not Bold = Deoxygenated Blood

In the Pulmonary Circuit, where does Deoxygenated blood pass from?

Where is the blood oxygenated?

Where does the oxygenated blood then go?

How does it get there?

Passes from the Right Ventricle to the Pulmonary Arteries and the Lungs

Blood is oxygenated in the Lungs

Oxygenated blood then goes to the Left Atria

It is carried by the Pulmonary Veins

Is blood carried in the Pulmonary Arteries oxygenated or deoxygenated?

Does this follow the rule?

Deoxygenated

No; Arteries normally carry Oxygenated blood

Is blood carried in the Pulmonary Veins oxygenated or deoxygenated?

Does this follow the rule?

Oxygenated

No; Veins normally carry Deoxygenated blood

In the Systemic Circuit, where does Oxygenated blood pass from?

Where is the blood deoxygenated?

Where does the deoxygenated blood then go?

How does it get there?

Passes from the Left Ventricle to the Aorta and Tissues

Blood is deoxygenated in the Tissues via Internal Respiration (load CO2, unload O2)

Deoxygenated blood then travels to the Right Atrium (chamber of the heart)

Travels through the Inferior / Superior Venae Cavae

Which blood circuit is longer / has blood travel the furthest?

Is it under higher or lower pressure?

Why?

Systemic Circuit is longer

Higher pressure

Has to drive the blood at higher pressure due to higher resistance

What is Parallel Flow?

What are the advantages of Parallel Flow?

Blood flows to organs at the same time instead of from one organ to another

Advantages include:

1. Each organ is fed by a separate artery, so each one gets fully oxygenated blood (not diluted)

2. Blood can be regulated independently for each organ (some need more blood than others)

What are Reconditioning Organs?

Which organs are considered to be this?

Are there exceptions?

Organs get different levels of blood flow depending on their needs

All organs in the human body are considered Reconditioning Organs

EXCEPT the Brain, which needs the same amount of blood at all times

What is the general path of Coronary Circulation?

Why does this occur?

1. Left Ventricle

2. Aorta

3. Coronary Arteries

4. Myocardium

5. Coronary Veins

6. Coronary Sinus

7. Right Atrium

Occurs because the Heart Muscle is a tissue too and needs a blood supply

What is Systole?

Diastole?

When does most Coronary Circulation occur?

Systole — when the heart is contracting

Diastole — when the heart is relaxing

Most Coronary Circulation occurs during Diastole / when the heart is relaxed

What happens during Coronary Artery Diseases (CAD)?

Pathology changes in the walls of the Arteries cause decreased blood to the Myocardium

What is the general process of Vascular Spasms?

1. Spastic contractions of the Coronary Arteries

2. Diameter of the Coronary Arteries narrow

3. O2 delivery to the Myocardium is limited

4. Causes a Myocardial Ischemia (inadequate blood supply to the heart)

5. Heart enters into a Hypoxic Condition

6. Chest pains / Angina Pectoris

What are some common causes for Vascular Spasms?

Are they reversible?

Exposure to cold, physical exercise, and anxiety

Yes, they are reversible

What is Atherosclerosis?

What causes it?

Progressive, degenerative Coronary Artery disease that is non-Reversible

Caused by consuming too much LDL (bad cholesterol)

Too much LDL causes formation of blood plaques that block the delivery of O2 through blood vessels

What is Myocardial Ischemia?

What happens if it progresses enough?

Inadequate delivery of oxygen to the Myocardium

If it progresses enough, it can cause the Myocardium to die

This can lead to Necrosis, which can cause a Myocardial Infarction (Heart Attack)

What is the white tissue that you see in a heart that suffered from Myocardial Infarction?

White Myocardial Tissue = Dead / Necrotic heart tissue

What is used by doctors to see blockages in the blood flow?

Coronary Angiograms

Is a blockage worse in the Left Coronary Arteries or the Right Coronary Arteries?

Why?

Left Coronary Arteries

They are the arteries that deliver blood to the Systemic Circuit, which specifically needs higher pressure to deliver blood

Otherwise, the tissue dies and blood cannot be transferred to other organs

What are the three main treatments used on patients suffering from Atherosclerosis?

1. Angioplasty — balloon is used to get past the plaque and open a narrow section of the Coronary Artery so blood can flow better

2. Stents — used alongside Angioplasty; wire mesh is used to keep the artery open by pushing the plaque to the side

3. Nitroglycerin (drug) Treatment — Nitroglycerin tablets relax the smooth muscle lining the blood vessels of the Coronary Artery to allow for more oxygen delivery

How does Nitroglycerin work mechanistically?

1. Nitroglycerin in the body turns into Nitric Oxide, which reacts with Receptors associated with Guanylate Cyclase on the smooth muscle of blood vessels

2. Guanylate Cyclase is activated and increases the production of cGMP (second messenger)

3. cGMP activates Protein Kinase G, which dephosphorylates the Myosin Light Chain of smooth muscle

4. Number of cross-bridges formed decreases

5. Calcium is sequestered out and causes less to bind to Calmodulin

6. Relaxation of the Vascular Smooth Muscle

What are the two types of Valves in the heart?

What do they separate?

1. Atrioventricular (AV) Valves — separates the Atria from the Ventricles

2. Semilunar (SL) Valves — separates the Ventricles from the Blood Vessels (specifically the Arteries)

What are the two kinds of AV Valves?

1. Right (Tricuspid) Valve

2. Left (Bicuspid / Mitral) Valve

What are the two kinds of SL Valves?

Which Ventricles and Arteries do they separate?

1. Pulmonary SL Valve — separates the Right Ventricle and the Pulmonary Arteries

2. Aortic SL Valve — separates the Left Ventricle and the Aorta

Do AV Valves contain Chordae Tendineae?

SL Valves?

Yes

No; however, their moon shape keeps them from prolapsing

What is the general process of the AV Valve in action?

1. Ventricles relax

2. Left and Right Atria fill with blood and opens the Bicuspid (Left) / Tricuspid (Right)

3. Left and Right Ventricles fill with blood, causing the Myocardium to contract

4. Papillary Muscles contract, keeping the AV Valve from prolapsing

5. AV Valves closes because the pressure in the Ventricle is higher than in the Atria

What causes the AV Valves to close?

Pressure in the Ventricles is higher than in the Atria

What is the general process of the SL Valve in action?

1. High pressure in the Ventricles (causes by their contraction) opens the SL Valves

2. Ventricles relax and cause the pressure in the Ventricles to be less than the pressure in the Arteries, causing the SL Valves to close

What causes the SL Valves to close?

Ventricles relax, causing the pressure in the Ventricles to be less than the pressure in the Arteries

What is the main function of Pressure Operated Valves?

Allows for unidirectional blood flow based on the pressure gradient

High pressure behind the Valve causes it to open

Low pressure behind the Valve / high pressure in front of the Valve causes it to close