A&P II Quiz #4

What is contained in the pericardial cavity?

Pericardial fluid

Is the fibrous pericardium soft or tough?

Tough

Which layer of the serous pericardium is directly in contact with the heart?

The visceral layer

What is another name for the visceral pericardium

The epicardium

What is the epicardium?

The most superficial layer of the heart

What are the 3 layers of the heart from superficial to deep?

1) Epicardium

2) Myocardium

3) Endocardium

What does the epicardium do?

It anchors the heart to the pericardium

What does the epicardium often contain?

Fat

* Energy for the heart
* Protection for the heart

What is the myocardium?

The layer of the heart that actually contracts

What are cardiac cells called?

Myocites

What is the endocardium directly in contact with?

The blood

What is the endocardium?

A really thin layer that is a blood barrier between the blood and the myocardium

Why does the endocardium have to protect the heart from the blood?

To protect the heart from nutrients and things in the blood

* If you ate too much sodium you don’t want your heart to spazz because of the sodium in the blood

What are the 4 chambers of the heart?

1) Right atria

2) Left atria

3) Right ventricle

4) Left ventricle

What is the septum?

A wall barrier dividing the heart into the right and left sides

What are the 2 types of septum there can be?

1) Interatrial septum

2) Interventricular septum

What are the 2 types of valves in the heart?

1) Atrioventricular valves

2) Semilunar valves

What are the 2 atrioventricular valves in the heart?

1) Tricuspid valve (3 flaps)

2) Bicuspid valve (2 flaps)

Where is the tricuspid valve located?

Between the right atria and right ventricle

Where is the bicuspid valve located?

Between the left atria and the left ventricle

What are the 2 semilunar valves in the heart?

1) Aortic semilunar valve

2) Pulmonary semilunar valve

Where is the aortic semilunar valve located?

Between the left ventricle and aorta

Where is the pulmonary semilunar valve located?

Between the right ventricle and the pulmonary trunk or artery

What are atria in the heart?

Receiving chambers

Where does the right atrium receive blood from?

The body

Is blood entering the right atrium oxygenated or deoxygenated?

Deoxygenated

Where does the left atrium receive blood from?

The lungs

Is the blood entering the left atrium oxygenated or deoxygenated?

Oxygenated

What structure do both atria have?

Auricles

What are auricles?

Little pockets that hold extra blood if it needs to be stored

What does the right atrium have on the inner side of its anterior flap?

Pectinate (comb-like) muscles

Does the left atrium have pectinate muscles?

No

* It’s very smooth

Why does the right atrium have pectinate muscles?

They allow it to contract a little harder than the left atrium

Which atria receives more blood?

The right atria

Why does the right atria use auricles?

Because you don’t how much blood is coming back from the body based on a lot of factors

Why does the left atria use auricles?

Because in unhealthy individuals, blood can back flow

What does the left ventricle have more than the right ventricle of?

More mass, more myocardium

What are the muscles in the ventricles called?

Trabeculae carneae

What do trabeculae carneae help with?

Contracting and firing power

What muscles are extensions of trabeculae cornea?

Papillary muscles

Are papillary muscles or trabeculae cornea bigger and more pronounced?

Papillary muscles

What do papillary muscles do?

They keep valves shut while the heart is contraction

What are papillary muscles attached to?

Chordae tendineae

What are chordae tendineae?

Heart strings

Why are chordae tendineae important?

They make sure blood flows in one direction

What are ventricles?

Chambers that pump blood out of the heart

When the right ventricle contracts, where does the blood go?

To the lungs

When the left ventricle contracts, where does the blood go to?

The aorta and to the body

* It’s systemic

Which ventricle is affected by bad diets and high blood pressure?

The left ventricle because it has to overcome more pressure because the pressure in the left ventricle has to be greater than the pressure in the rest of the body

What happens to the left ventricle the harder it has to work?

It gets weaker and weaker

* Blood starts to accumulate and back flows through the left atrium and eventually to the lungs

What is congestive heart failure?

When the left ventricle gets so weak that blood back flows to the lungs

From what veins does blood enter the right atrium?

* Superior Vena Cava
* Inferior Vena Cava
* Coronary Vein (or Sinus)

Where does the superior vena cava collect blood from?

Any blood above the diaphragm

Where does the inferior vena cava collect blood from?

Any blood below the diaphragm

What does the coronary sinus do?

It supplies blood to the myocardium

When blood leaves the right atrium, where does it go?

Through the pulmonary semilunar valve to the pulmonary trunk which splits into 2 pulmonary arteries that go to the lungs

Which side of the heart is the pulmonary circuit associated with?

The right side

What is the goal of the pulmonary circuit?

To get deoxygenated blood to the lungs

Which side of the heart is the systemic circuit associated with?

The left side

What is the goal of the systemic circuit?

To get oxygenated blood out to the body

Do the ventricles contract at the same or different times?

At the same time

Ideally, do the right and left ventricles pump the same or different amounts of blood?

The same

What is coronary circulation?

Arteries and veins supplying the myocardium of the heart with blood

What interferes with blood flow to the heart?

The heart contracting

* It causes pressure on the blood vessels

What does the coronary circulation do when the heart relaxes?

It promotes the delivery of oxygen and nutrients

Does the heart rely on the nervous system to contract?

No

What are the 2 types of cardiac cells?

1) Contractile cells

2) Intrinsic conducting cells (non-contractile cells)

Which cardiac cells need to be stimulated to contract?

Contractile cells

Which type of cardiac cells are very rare and don’t contract?

Intrinsic conducting cells

Why is the heart able to beat on its own when removed from the body?

Intrinsic conducting cells don’t need to be stimulated. They stimulate themselves

* They don’t rely on the nervous system

Can the intrinsic conducting cells be affected by the nervous system?

Yes

What stimulates contractile cells?

Intrinsic conducting cells

What is the intrinsic conducting system composed of?

Cells that generate their own rhythm

What are the 5 cells that generate their own action potentials?

1) SA node

2) AV node

3) Bundle of His (AV bundle)

4) The right and left sides of the Bundle of His (AV bundle)

5) Purkinje fibers

What speed of action potentials does the SA node generate?

About 70-80 bpm

What are the action potentials generated by the SA node called?

Pacemaker potentials

What is the SA node called?

The pacemaker of the heart

What speed of action potentials does the AV node generate?

About 40-60 bpm

Is the AV node life-sustaining?

Yes, but not for a long time

What are the Bundle of His and sides of the Bundle of His like?

Tract for signals to travel on

* No bpm generated

What speed of action potentials do purkinje fibers generate?

About 20-40 bpm

What is the start of the intrinsic conducting pathway?

The SA node in the right atrium below the superior vena cava

Where does an action potential travel after the SA node?

The AV node in the bottom of the right atrium

Where does the action potential go from the AV node?

To the Bundle of His which branches to the right and left Bundles of His in the middle of the heart

Where does the action potential go from the bundles of His?

To the purkinje fibers at the bottom of the heart

What do the purkinje fibers do?

Run the signals up the sides of the heart

* The fibers penetrate different layers of the heart stimulating contraction from the bottom of the heart

What special gate do intrinsic conducting cells have?

Funny sodium gates

Is the process of generating an action potential the same for all intrinsic conducting cells?

Yes

Do intrinsic conducting cells have resting membrane potentials?

No

* They are never at rest because of the funny sodium channels

What makes funny sodium channels funny?

They are ALWAYS open

What charge do intrinsic conducting cells start at?

\-60 mV

What channels are closed at -60 mV?

Potassium channels are closed

What ion takes you to -50 mV?

Sodium influx through the funny sodium channels

What channels open at -50 mV?

Transient-type Calcium channels open

What happens when the influx of calcium takes it to -40 mV?

* The transient-type calcium channels close
* The long-lasting calcium channels open

What type of channels are long-lasting calcium channels?

Voltage-gated channels

What do the long-lasting calcium channels opening take it to?

\-10 mV

At what charge does depolarization of intrinsic conducting cells end?

\-10 mV

What happens at the start of repolarization?

* Calcium channels close
* Potassium channels open

What charge does repolarization return intrinsic conducting cells to?

\-60 mV