Physiology III - UNIT 1 (Part 1 - Cardiovascular System Overview)

What are the two major divisions of the Cardiovascular System? Which side of the heart does each make up?

1) Pulmonary Circuit --> RIGHT

2) Systemic Circuit --> LEFT

Which major division of the Cardiovascular system connects the heart and lungs, carrying deoxygenated blood to the lungs for gas exchange, then oxygenated blood back to the heart?

Pulmonary Circuit

Which major division of the Cardiovascular system makes up the rest of the body and carries oxygenated blood to ALL tissues for gas exchange, then deoxygenated blood back to the heart?

Systemic Circuit

What are the 8 key structures (in order) that make up the Pulmonary Circuit?

1) Right Atrium

2) Tricuspid valve

3) Right Ventricle

4) Pulmonary valve

5) Pulmonary trunk

6) Right & Left Pulmonary Arteries

7) Lungs

8) Right & Left Pulmonary Veins

What is the valve between the right atrium and right ventricle? How many cusps does this valve have?

Tricuspid valve

(Right AV valve)

-- 3 cusps

Which structure carries deoxygenated blood FROM the heart to the lungs? What structure brings oxygenated blood TO the heart from the lungs?

FROM heart = L & R Pulmonary arteries

TO heart = L & R Pulmonary veins

What is the valve between the right ventricle and the pulmonary trunk?

Pulmonary valve

(Pulmonic valve)

Where does deoxygenated blood enter the heart?

Right Atrium

Normally, where do arteries go in reference to the heart, and what type of blood do they carry? How about veins? What are two exceptions to this rule?

Arteries go AWAY from heart carrying OXYGENATED blood

Veins go TO heart carrying DEOXYGENATED blood

Two exceptions = Pulmonary arteries (carries deoxygenated) and Pulmonary veins (carries oxygenated)

What are the 6 key structures that make up the Systemic circuit?

1) Left atrium

2) Mitral (bicuspid) valve

3) Left ventricle

4) Aortic valve

5) Aorta to body

6) Returns via superior & inferior vena cava

Which side of the heart recieves oxygenated blood from the lungs?

Left atrium

What is the valve between the left atrium and left ventricle? How many cusps does it have?

Mitral (bicuspid) valve

(Left AV valve)

-- 2 cusps

What structure carries oxygenated blood away from the heart?

Aorta

What is the valve between the left ventricle and the aorta?

Aortic valve

Which great vessels return deoxygenated blood to the heart?

Superior & Inferior vena cava

(also coronary sinus)

The left ventricle is significantly more powerful/muscular than the right ventricle. Describe how the structural difference relates to the functions of the systemic and pulmonic circuits?

Left ventricle needs to be stronger because it must pump blood throughout body against gravity (since part of systemic circuit)

- Right ventricle also pumps against gravity but a much shorter distance to the lungs

What are the functions of the pericardium layers?

Allow heart to beat without friction and allow room for heart to expand

What are the two layers of the pericardium?

1) Outer (fibrous) layer

2) Inner serous pericardial layer

What are the two parts of the Serous pericardium?

1) Parietal layer of serous pericardium

2) Visceral layer of serous pericardium (EPICARDIUM)

What are the three layers of the heart wall?

1. Epicardium

2. Myocardium

3. Endocardium

Which layer of the heart wall is the smooth inner lining of heart and blood vessels that covers the valve surfaces and is continuous with the endothelium of blood vessels?

Endocardium?

Which layer of the heart wall is the serous membrane covering the heart, with adipose in thick layers in some places? What travels through this layer?

Epicardium (visceral layer of serous pericardium)

- Coronary blood vessels travel through this layer

Which layer of the heart wall consists of cardiac muscle that wraps in SPIRALS around the heart and is the fibrous skeleton of the heart?

Myocardium

Which layer of the heart provides structural support and attachment for cardiac muscle and anchor for valve tissue?

Myocardium

The electrical insulation between the atria and ventricles is important for what?

Timing & coordination of contractile activity

What are the 4 great vessels of the heart? What circuit are each of these a part of?

1) Pulmonary trunk --> Pulmonary Circuit

2) Ascending aorta --> Systemic circuit

3) Superior vena cava --> Systemic circuit

4) Inferior vena cava --> Systemic circuit

What are the two superior chambers of the heart? What are the two inferior chambers of the heart?

Superior = right & Left Atria

Inferior = right & left ventricles

Which chambers of the heart receive blood returning to the heart? Which pump blood into the arteries?

Receive blood: R & L Atria

Pump blood: R & L Ventricles

What is the purpose of the auricles seen on the surface of the heart?

Enlarge chamber and help push blood into atrium

What internal feature on the chambers of the heart are the internal ridges of myocardium in the right atrium and both auricles?

Pectinate muscles

What is the function of the pectinate muscles?

Allows for stretch to increase the volume and help overcome constantly changing volume status of right atrium

- This is why less developed in left atrium

What internal feature on the chambers of the heart are the internal ridges in both ventricles?

Trabeculae carneae

What are the 2 functions of the trabeculae carneae?

- prevent ventricle walls from sticking together after contraction (decreases suction)

- Serve similar function to papillary muscles in their contraction pulls on chordae tendinea to prevent prolapse of mitral and tricuspid valve

Which valves control the blood flow between the atria and ventricles?

Atrioventricular (AV) valves

What are the tough tendinous cords that connect/hold AV valves to papillary muscles on the floor of the ventricles while blood is pumping? Why?

Chordae tendineae

-- prevents AV valves from flipping or bulging into atria when ventricles contract

Each papillary muscle has 2-3 attachments to the heart floor in order to allow what 3 things?

1) Distribute physical stress

2) Coordinate timing of electrical conduction

3) Provide redundancy

Which valves control flow into great arteries (pulmonary trunk & aorta), and opens/closes because of blood flow and pressure?

Semilunar valves

T/F: The atrioventricular valves need more pressure than the semilunar valves in order to open

FALSE

- Semilunar valves need more pressure to open (also pumping out to body rather than into heart)

- Gravity helps the AV valves open

What is volume vs blood volume referring to?

Volume = space (aka AVAILABLE volume/space)

Blood volume = actual measurement of blood

What is the most common valve to be replaced? What is the most common valve to be repaired?

Replaced: Aortic valve

Repaired: Mitral valve

What is the condition in which the valve opening becomes narrow and restricts blood flow?

Stenosis

What is the condition where a valve slips out of place, or the valve flaps (leaflets) do not close properly?

Prolapser

What is the condition in which blood leaks backward through a valve, sometimes due to prolapse?

Regurgitation

What is the 11 steps of blood flow through the chambers of the heart?

1) Blood enters right atrium from superior & inferior vena cava

2) Blood in right atrium flows through right AV valve into right ventricle

3) Contraction of right ventricle forces pulmonary valve open

4) Blood flows through pulmonary valve into pulmonary trunk

5) Blood is distributed by right and left pulmonary arteries to lungs where it unloads CO2 and loads O2

6) Blood returns form lungs via pulmonary veins to left atrium

7) Blood in left atrium flows through left AV valve into left ventricle

8) Contraction of left ventricle (simultaneous with step 3) forces aortic valve open

9) Blood flows through aortic valve into ascending aorta

10) Blood in aorta distributed to organs in body unloading O2 and loading CO2

11) Blood returns to right atrium via venae cavae

What is the relationship between volume, pressure, and blood volume?

Pressure & Blood volume proportional; Volume is disproportional

As Volume increases, Pressure & Blood volume decreases

As Volume decreases, Pressure & Blood volume increases

Once the ventricles contract & eject blood, they are now in a RELAXED state with volume ______, pressure _______, and blood volume _______.

Volume increased

Pressure decreased

Blood volume decreased

With the ventricles in a relaxed state, semilunar valves close as the blood attempts to back up into the ventricles form the great vessels due to the aortic and pulmonary trunk having a _______ Volume and ______ Pressure compared the the ventricle.

Decreased volume (space)

Increased pressure

(compared to the current low ventricle pressure)

As the atria fill, the volume ________, pressure _______, and blood volume _______

Volume decreases

Pressure increases

Blood volume increases

Due to the filling of the atria with blood, what occurs?

AV valves open and blood flows form the atria to ventricles

The AV valves will close as what occurs?

As blood attempts to back up into the atria (ventricle contraction)

What happens to the pressure when the ventricles contract? What valve does this affect?

Increases pressure

- Semilunar valves open and blood flows into great vessels (Aorta & Pulmonary trunk)

- AV valves also CLOSED to prevent blood going backward

--> aka ejecting blood, which leaves the ventricles in a relaxed state which starts the cycle over

When the ventricles are in a relaxed state (ready to fill), you would predict that the _____ valves would be closed and the _____ valves would be open?

Semilunar

Atrioventricular

5% of blood pumped by the heart is pumped to the heart itself through what circuit to sustain its strenuous workload?

The Coronary Circulation

-- 250mL of blood per min and needs abundant O2 and nutrients

The left coronary artery (LCA) branches off what? What 4 features does this artery supply?

Branches off ascending aorta

Supplies

1) Left atrium

2) Left ventricle

3) Interventricular septum

4) AV bundles

What two branches of the left coronary artery (LCA) supplies blood to BOTH ventricles, and the anterior 2/3 of the interventricular septum?

Anterior interventricular branch (AIV) & Left anterior descending artery (LAD)

What branch of the left coronary artery (LCA) passes around the left side of heart in the coronary sulcus? What 2 features of the heart does it supply?

Circumflex branch

Supplies

1) Left atrium

2) Left ventricle

What branch is given off by the Circumflex branch on the posterior end of the heart? What does it supply?

Left marginal branch

Supplies

- Posterior wall of left ventricle

What 4 features of the heart the Right Coronary artery (RCA) supply?*

Supplies:

1) Right atrium

2) Sinoatrial node (pacemaker)

3) AV node

4) Posterior part of interventricular septum

NOTE: branches off ascending aorta

What branch of the right coronary artery (RCA) supplies the lateral aspect of the right atrium and ventricle (apex)?

Right marginal artery

What branch of the right coronary artery (RCA) supplies the posterior walls of ventricles and posterior 1/3 interventricular septum?

Posterior interventricular branch

Why is the flow through coronary arteries greatest when the heart is relaxed? (3)

1) contraction of myocardium compresses coronary arteries and obstructs blood flow

2) Opening of aortic valve flap during ventricular systole (cx) covers openings to the coronary arteries blocking blood flow into them

3) During ventricular diastole (rx) blood in aorta surges back toward heart and into openings of coronary arteries

What does cx and rx stand for?

Contract = cx

Relax = rx

What is a constriction (narrowing/blocking) of the coronary arteries, usually as a result of atherosclerosis?

Coronary artery disease (CAD)

What is an accumulation of lipid deposits that degrade the arterial wall and obstruct the lumen?

Atherosclerosis

What is transient chest pain from partial obstruction of coronary blood flow due to ischemia of cardiac muscle during exercise, is quickly resolve upon rest, but the obstruction partially blocks blood flow, causing anaerobic fermentation and production of lactate and pain stimulation?

Angina Pectoris

NOTE: If untreated can lead to Myocardial infarction

What is the sudden death of a patch of myocardium resulting from long-term obstruction of coronary circulation due to an atheroma obstructing the artery, cardiac muscle downstream dies, heavy pressure/pain radiates into left arm, and electrical conduction can be disrupted? What percent of deaths in the US does this pathology make up?

Myocardial infarction (MI)

- 25%

50% of all myocardial infarctions involve what artery (aka the widow-maker)?

Left anterior descending artery

-- stops all blood flow to left side of heart

What are the 3 main venous structures that drain into the coronary sinus? Where does the coronary sinus drain?

1) Great cardiac vein

2) Posterior interventricular vein

3) Left marginal vein

Coronary sinus empties into right atrium