blood vessels and heart review guide bio 202
f. What ion is responsible for repolarization? (Cardiocyte)
Calcium ion channels close, potassium channels open. Rapid potassium efflux (out) returns cell to resting potential.
27. What is the scientific term for the "heart strings" that extend from the AV cusps to the papillary muscles? What is their function?
Chordae tendinae. They help shut the valves and prevent blackflow.
8. Describe the importance of the elasticity of an artery? What happens to this elasticity as one ages? How would this affect a person?
Elasticity of an artery is important because it maintains blood pressure even when the heart relaxes. This elasticity fades as one ages and can affect a person's blood pressure.
19. What is the inner lining of the heart called?
Endocardium: inner surface of the heart, including the heart valves
5. What is a venipuncture?
Fresh whole blood is generally collected from a superficial vein, such as the median cubital vein on the anterior surface of the elbow.It is a common sampling technique because (1) superficial veins are easy to locate, (2) the walls of veins are thinner than those of comparably sized arteries, and (3) blood pressure in the venous system is relatively low, so the puncture wound seals quickly.
36. Draw AND label the arrangement of blood vessels arising from the aortic arch
From left to right Ascending arch---- brachicephalic artery--- right subclavian artery, right common carotid artery----- left common carotid artery---- left subclavian artery.
g. How does the length of the action potential compare to an action potential in a skeletal muscle cell? Why is this important?
In a typical nerve, the action potential duration is about 1 ms. In skeletal muscles, the action potential duration is approximately 2-5 ms. This is important because it shows that cardiac muscles is not able to create another action potential too soon due to long relatice refractory period. This provides time for the chambers to completely empty and refill. The length of time between depolarization and repolarization is long. This refractory period is about the same amount of time between the contraction and relaxation of the heart muscle. Because of this, the cardiac muscle does not tire as easily.
29. What are papillary muscles? What are their functions?
They are what the chordae tendinae attaches to help shut the valve.
veins
blood returns back to heart, thinner-walled because blood travels back to heart at low speed and pressure from the fact that it is far away, and there are valves in large veins to allow blood to flow only toward heart.
pulmonary circuit
blood vessels that carry blood to and from alveoli of lungs for gas exchange (right side of heart)
Myocardial infarction
complete obstruction causes death of cardia cells in affected area. Pain or pressure in chest that often radiates down left arm.
systemic circuit
transports blood to and from rest of body (left side of heart)
3. What layer of an artery consists mostly of smooth muscle?
tunic media
25. What are the bottom two chambers of the heart called?
ventricles
h. Summarize the role of calcium ions in cardiac muscle contractions.
20 percent of calcium ions required for a contraction comes from calcium ions entering through the plasma membrane during the plateau phase. Arrival of extracellular calcium ions: triggers release of calcium ion reserves (the other 80 percent) from sarcoplasmic reticulum (SR). As slow calcium channels close: intracellular calcium ions is absorbed by the SR or pumped out of cell. Cardiac muscle tissue is very sensitive to extracellular calcium ion concentrations.
33. What are the veins, in relation to the cardiovascular system, which carry oxygenated blood? How many are there?
4. Left pulmonary veins and right pulmonary veins.
1. What are the functions of an artery, arteriole, vein, venule, and capillary?
Arteries carry oxygen rich blood from heart. Veins carry oxygen deficient blood back to heart. All blood is red. Blood flows from capillaries to heart through venules and veins. Blood flows from heart through arteries and arterioles to capillaries.
14. Compare and contrast the apex and the base of the heart.
Base: broad superior portion of heart Apex: inferior end, tilts to the left, tapers to point
c. What is the threshold value?(Cardiocyte)
The threshold value is -40 mv
e. The influx of calcium into the heart cell causes what to happen. Hint: Think actin and myosin! (Cardiocyte)
Increased amount of calcium ions into cytosol causes contraction.
21. Where would you find the interatrial septum and interventricular septum of the heart?
Interatrial septum: wall between atria Interventricular septum: thicker wall between ventricles
39. What the heck is a CABG? Generally explain the procedure.
Involves bypassing major blocks in the blood vessels of the heart to improve the blood to the cardiac muscle (myocardium). The conduits used for the bypass grafting can be veins taken from the legs or arterial conduits which include the mammary arteries from the chest wall, the radial artery from the forearm and an artery from near the stomach.
16. What is the name given to the thin, tough sac which covers the heart? What happens if blood gets caught in the space between between this sac and the heart itself?
It is called a pericardial sac. It would cause a pericardial tamponade.
43. Explain the concept of overdrive suppression, including the intrinsic pacemaker rates of the different regions of the heart.
Latent pacemakers include cells of the AV node, Bundle of His, and Purkinje fibers. Pacemaker cells with fastest rate of phase 4 control HR and shortest refractory period. SA node cells recover faster and are the first to fire an action potential. When SA node drives the heart, latent cells are suppressed, which refrers to overdrive suppression. The intrinsic firing rate for the SA node is 70-80, AV node is 40-60, Bundle of His is 40, and Purkinje fibers are 15-20.
18. What type of tissue comprises the bulk of the myocardium?
Muscle wall of the heart (forms both atria and ventricles) that contains blood vessels and nerves
a. What is the resting potential value? (Cardiocyte)
Myocytes have stable resting potential of -90 mv
40. What does myogenic mean? How about autorhythmic?
Myogenic: heartbeat originates within heart Autorhythmic: regular, spontaneous depolarization
48. List AND describe the key differences between a skeletal muscle AP and a heart muscle cell AP.
One. All-or-none law: gap junctions allow all cardiac muscle cells to be linked electrochemically, so that activation of a small group of cells spreads like a wave throughout the entire heart. This is essential for "synchronistic" contraction of the heart as opposed to skeletal muscle. Two/. Automacity (autorhythmicity): some cardia muscle cells are "self-excitable" allowing for rhythmic waves of contraction to adjacent cells throughout the heart. Skeletal muscle cells must be stimulated by independent motor neurons as part of a motor unit. Three/ length of absolute refractory period: the absolute refractory period of cardiac muscle cells is much longer than skeletal muscle cells (250 ms. 2-3 ms), preventing wave summation and tetanic contractions which would cause the heart to stop pumping rhthymically.
46. List several ways that a ventricular heart cell and pacemaker heart cell differ in terms of action potential generation.
Pacemaker heart cells have three gos before there is action in a ventricular heart cell.
a. What ions slowly leaks out of the cell, helping the cell to begin to depolarize? (pacemaker cell)
Potassium leak channels allow potassium OUT of the cell more slowly than in skeletal muscle. Specialized sodium channels allow sodium IN, generating a slow inward flow of sodium ions into the cell of the SA node.
28. What does prolapse and regurgitation refer to in terms of the heart?
Prolapse: valve opens backwards. Blood can then regurgitate—causes the backflow of blood across the valve.
follow the electrical impulse through the heart again
SA node activity and atrial activation begin Stimulus spreads across the atrial surfaces and reaches the AV node There is a 100msec delay at the AV node, atrial contraction begins. The impulse is distributed by Purkinje fibers and relayed throughout the ventricular myocardium. Atrial contraction is completeted, and ventricular contraction begins.
42. Follow an electrical impulse through the heart, beginning at the sinoatrial (SA) node.
SA node: pacemaker, initiates heartbeat, sets heart rate AV node: electrical gateway to ventricles. This is where there is a brief delay so atria can contract before ventricles. AV bundle: pathway for signals from AV node. Right and left bundle branches are divisions of AV bundle that enter interventricular septum Purkinje fibers: upward from apex spread throughout ventricular myocardium in order to maximize ventricular ejection.
Anterior and posterior interventricular sulci:
Separate left and right ventricles Contain blood vessels of cardiac muscle
41. What region of the heart is referred to as the pacemaker?
Sinoatrial node. SA node
d. When sodium gates close, which gates open?(Cardiocyte)
Slow calcium ion channels open, calcium ions bind to fast calcium ion channels which releases increased amount of calcium ions into cytosol which causes contraction.
what causes the threshold to be reaches(Cardiocyte)
Stimulus (from neighboring cardiocyte) opens voltage regulated sodium ion gates and sodium rushes in, so the membrane depolarizes (increases) rapidly
26. Where are the SVC and IVC? What do they drain into?
Super vena cava and inferior vena cava and they drain into the right atrium.Coronary sinus also returns blood from the heart itself into the right atrium.
d. How does the pacemaker cell repolarize?
The calcium channels are rapidly inactivated, soon after they open. Potassium permeability is increased, and the efflux of potassium (loss of positive ions) slowly repolarizes the cell.
b. What is the funny current? (Pacemaker cell)
These sodium channels open more readily when the membrane is hyperpolarized (more negative). This is called this
37. Discuss the role and the importance of the coronary arteries and coronary veins.
The coronary arteries originate at the base of the ascending aorta, at the aortic sinuses. Blood pressure here is the highest in the systemic circuit. the combination of elevated blood pressure and elastic rebound ensures a continuous flow of blood to meet the demands of active cardiac muscle tissue.Most likely, the coronary veins give the heart its nutrients that are needed in order to pump properly.
30. Which side of the heart has a thicker ventricular wall? Why?
The left side of the heart is thicker than the right because it pumps blood to the whole body and so it needs more umph.
15. Explain the relationship between the parietal pericardium and the epicardium.
The parietal is the outermost layer and the epicardium is the inner layer. It holds the heart together but also forms the inner side of the pericardial sac.
47. Describe the importance of the plateau in a heart cell's action potential. What ion is responsible for this plateau?
The plateau extends the absolute refractory period of the cardia muscle cell. Cardia muscle is not able to create another action potential too soon due to long relative refractory period. This provides time for the chambers to completely empty and refill. The length of time between depolarization and repolarization is long. The refractory period is about the same amount of time between the contraction and relaxation of the heart muscle. Because of this, the cardiac muscle does not "tire" as easily.
34. What are the arteries, in relation to the cardiovascular system, which carry deoxygenated blood? How many are there?
The pulmonary trunk divides into right and left pulmonary arteries.
24. What chambers of the heart function to receive blood from the veins?
The right and the left atrium receive blood from the veins. The right gets blood from SVC and IVC and coronary sinus while the left gets blood from the pulmonary veins.
c. What ion is primarily responsible for depolarization once threshold is reached? (pacemaker cell)
Threshold is between -40 m and -50 mv, much lower than a neuron. Voltage sensitive calcium channels open at threshold, generating a slow depolarization. There are no fast sodium channels like in a neuron or cardiac muscle cell.
22. Where will you find the bicuspid and tricuspid valves in the heart? These valves are sometimes referred to as AV valves? What does AV stand for?
Tricuspid valve is in the right side of the heart between the right atrium and the right ventricle and the bicuspid valve is in the left side of the heart between the left atrium and the left ventricle. They can be called AV valves which also means atrioventricular valves.
2. From outermost to innermost, what are the three tunics (layers) of an artery.
Tunica adventitia, tunica intima, and tunica media
varicose veins
Varicose veins are causes by poor blood circulation from standing on legs all the time that there is no compression to keep veins to have a normal blood flood. The valve in big veins become deformed and the vein dilates which causes the skin to bulge and have abnormal blood flow.
4. Why do larger veins have valves?
Veins hold way more blood volume than an artery. blood tends to sit more in our veins. Valves prevent backflow
23. Where will you find the pulmonary and aortic semilunar valves in the heart?
You would find it in the pulmonary trunk and the other one would be in the aorta.
13. The bulk of the heart rests on this side of the body
anterior
arteries
blood flows away from heart, thicker walls to provide strength for high pressure pumping of blood, elastic and stretchable to maintain blood pressure even when heart relaxes
coronary sulcus
divides atria and ventricles
depolarization, repolarization
increase membrane potential. decrease membrane potential
6. What is the name of the space in a blood vessel where blood flows?
lumen
11. What is the specific space in the thoracic cavity where the heart is located?
mediastinum
hat is the muscular (middle) layer of the heart is called?
myocardium
stenosis
narrowed valve--- blood cannot move as well in the forward direction across the valve.
Angina pectoris
partial obstruction of coronary blood flow can cause chest pain. This chest pain is caused by ischemia (restricted blood flow), often activity dependent.
Sodium and potassium leak channels:
potassium leak permeability out of the cell, sodium leak permeability into the cell. Balance of the two determines resting membrane potential. Inside is mostly K (potassium). Outside is mostly sodium.
sodium ions, potassium ions, and calcium ions
sodium is high outside, potassium is high inside. Calcium is high outside.
what protects the heart anteriorly
sternum
