CH 21: The Heart Flashcards
The heart keeps blood in what?
It beats — per minute
Motion
70 beats per minute
What are the four chambers of the heart?
Right and left atria(top)
Right and left ventricles (bottom)
What are the two circuits the heart pumps blood into?
Pulmonary circuit
Systemic circuit
What is the pulmonary circuit?
The right side of the heart (right atrium and right ventricle) receive and then pump blood to the lungs. Right side pumps to lungs and then back to the left and that is called “pulmonary circuit”
What is the systemic circuit?
The left side receives the blood in the left atrium, and then the left ventricle pumps the blood out to the entire rest of the body (exclusion of the lungs). Left ventricle pumps to the entire body, then flows back to the right side which is called “systemic circuit”
Each of the circuit involves?
Arteries
Veins
Capillaries
What do arteries do?
Transports blood “away” from the heart
What do veins do?
Transport blood “toward” the heart
What do capillaries do?
What happens here?
They are vessels that interconnect arteries and veins
This is where gas exchange happens
What is the pericardium?
What are the two layers?
Pericardium is the serous membrane lining the pericardial cavity
The two layers are visceral and parietal pericardium
— visceral and parietal are the same membrane folded in on itself
What is cardiac tamponade?
This is when there’s excessive fluid in the pericardial cavity which increases pressure on the heart
What are the three layers of the heart walls?
Epicardium- external surface it’s right on top of the heart
Myocardium - consist of cardiac muscle cells ( big, beefy, part of the heart)
Endocardium - internal surface made of simple squamous epithelium
What are intercalated discs made of?
Desmosomes - intercellular junctions that provide strong adhesion between cells
Gap junctions - in the heart it mediates intercellular communication
What surrounds all four valves and what is its function?
Fibrous skeleton
It anchors valve cusps, prevents overdilation of valve openings, gives the muscle leverage(something to pull on), and blocks direct spread of electrical impulses (acts as an insulator)
Where does the apex of the heart rotate toward?
The left side, and that is why the left lung has the cardiac notch to accommodate the apex of the heart
Why is the myocardium twisted (spiraled) within the heart?
The twisting and spiraling of the myocardium allows the heart as it squeezes to twist so the blood can be moved out of the chambers efficiently, which helps each heartbeat.
What is the purpose of the interatrial grove?
It’s separates the left and right atria
What is the purpose of the coronary sulcus?
It separates the atria and the ventricles
What is the purpose of the anterior and posterior interventricular sulcus?
It separates the left and right ventricles
What kind of blood does the right atrium receive?
It receives deoxygenated blood (depleted of oxygen) via the superior vena cava, inferior vena cava, and coronary sinus
What are the ridges in the right atrium?
Pectinate muscles
What is the fossa ovalis?
It is the smooth oval portion in the atrium
What kind of blood does the right ventricle receive and from where?
It receives deoxygenated blood from the right atrium
Blood enters the ventricle by passing through the tricuspid valve
Blood leaves the ventricle by passing through the pulmonary valve
What is another name for the tricuspid valve in the right chambers?
Right atrioventricular valve
( Right AV valve)
The tricuspid (right AV valve) is connected to the papillary muscles via what?
The chordae tendineae
What is the trabeculae carneae and it’s function?
It is the muscle going in different directions
It helps the ventricles contract in different directions
What is the purpose of the papillary muscles and the chordae tendineae?
It prevents valve inversion when the ventricles contract
( it keeps the valve stabilized so blood flows in one direction and not backwards)
What kind of blood does the left atrium receive and from where?
It receives oxygenated blood from the lungs via the right, and left pulmonary veins
What is the two other names for the bicuspid valve?
Left atrioventricular valve
(Left AV valve)
Mitral valve
The left ventricle has the thickest wall. Why is that?
It is needed for strong contractions to pump blood throughout the entire systemic circuit ( Pumping blood to everywhere in the body, except for the lungs)
Blood leaves the left ventricle by passing through the ?
Aortic valve
What is the right ventricle shape and kind of wall?
Half moon shape
Thin walls with weaker contractions
What is the left ventricle shape and kind of wall?
Cylindrical shape
Thicker wall with powerful contraction
— 6 to 7 times more powerful than the right ventricle
What are the four valves in the heart?
Two AV valves
- Tricuspid
- Bicuspid
Tri before you Bi
Two Semilunar valves
- Aortic
- Pulmonary
All the valves do not open at the same time
What is the cardiac cycle?
The cardiac cycle is the coordination of the filling and emptying of blood by electrical signals that caused the heart muscles to contract and relax.
What is the valve function during the cardiac cycle?
-Papillary muscles relax
-Due to the pressure in the atria, the AV valves open
-When the ventricles contract, pressure causes semilunar valves to open
-Also upon contraction, the blood force is the AV valves closed, does resulting in blood going through the semi lunar valves
Know the right coronary artery (RCA) and the left coronary artery (LCA) on the heart diagram
Right coronary artery
-Right marginal branch
-Posterior interventricular branch
Left coronary artery
-Circumflex branch
-Anterior interventricular branch
What does the coronary veins do?
Drain cardiac venous blood into the right atrium
What are the four coronary veins?
1.Great cardiac vein
2.Middle cardiac vein
3.Small cardio mean
4.Coronary sinus - drains directly into the posterior aspect of the right atrium
What is systole?
Contraction of the heart
( blood is injected into the ventricles)
( blood is injected into the pulmonary trunk in the ascending aorta)
What is diastole?
Relaxation of the heart
( Chambers are filling with blood)
Cardiac contractions are coordinated by?
Conducting cells
What are the two kinds of conducting cells?
Nodal cells — establish the rate of contractions
* Sinoatrial node
* Atrioventricular node
Conducting fibers — distribute the contractile stimulus to the myocardium
What is the pacemaker of the heart and how many action potentials per minute does it generate?
Sinoatrial node
80 to 100 action potentials for a minute
The Cardiac Cycle
What is the flow of electrical signal?
1.Impulse travels from the SA node to the AV node
—Atrial contraction occurs
2.Impulse travels from the AV node to the AV bundle
3.The AV bundle travels along the intraventricular septum, and then divides to form the right and left bundle branches
4.The bundle branches send impulses to the Purkinje fibers
— Ventricular contraction occurs
Nerves associated with the autonomic nervous system (ANS) innervate the ?
SA Node — ( sympathetic/parasympathetic)
AV Node — (sympathetic/parasympathetic)
Cardiac Cells — (sympathetic)
Smooth muscles in the cardiac blood vessels — (sympathetic)
Norepinephrine from the ANS causes?
An increase in the heart rate and force of contractions
Acetylcholine from the ANS causes?
A decrease in the heart rate and in the force of contraction
What controls the heart?
The medulla oblongata
Which center activates sympathetic neurons?
Cardioacceleratory center
(Increases heart rate)
Which center activates parasympathetic neurons?
Cardioinhibitory center
CN X (Vagus nerve) carries the signal
Heart rate decreases
Know the flow of blood in the heart
Blood enters right atrium from superior and inferior vena cavae.
Blood in right atrium flows through right AV valve (tricuspid) into right ventricle.
Contraction of right ventricle forces pulmonary semilunar valve open.
Blood flows through pulmonary valve into pulmonary trunk
Blood is distributed by right and left pulmonary arteries to the lungs, where it unloads CO2and loads Oxygen.
Blood returns from lungs from pulmonary veins to left atrium.
Blood in left atrium flows through left AV valve (mitral) into left ventricle.
Contraction of left ventricle ( simultaneous with Step 3) forces aortic semilunar valve open.
Blood flows through aortic valve into ascending aorta.
Blood in aorta is distributed to every organ in the body, where it unloads O and loads CO2.
Blood returns to heart from venae cavae
