1
Q
What are some characteristics of the Atrioventricular Node?
A
- Located at the interatrial septum.
- The AV Node receives the impulse and slow the signal.
- Serves as a delay signal that allows for ventricular filling.
1
Q
Where to veins carry blood to?
A
veins carry blood towards the heart
2
Q
Which hormones increase blood pressure (BP)?
A
- Epinephrine/Norepinephrine –increasesCO and causes vasoconstriction.
- Antidiuretic Hormone (ADH)- blood volume
- Angiotensin II – “”
- Aldosterone – “”
3
Q
Describe the tunica media of the artery
A
Very thick layer composed of smooth muscle cells and elastic fibers.
3
Q
What is angina pectoris
A
Chest pain due to a obstruction of cornary arteries
3
Q
What would an enlarged Q wave suggest?
A
myocardial infarction (heart attack)
3
Q
What would an enlarge R wave suggest?
A
Ventricular hypertrophy
(enlarged ventricle)
5
Q
What are characteristics of the arteries
A
- Strong, thick-walled vessels.
- Blood is under high pressure and high in oxygen; low in carbon dioxide.
- Branch into arterioles.
- Contain 3 distinct layers
7
Q
What structures are associated with the atrioventricular valves?
A
- Chordae Tendineae- tendon-like cords that connect the cusps of AV valves to the muscle of the ventricles. – Prevents cusps from swinging back into the atria.
- Papillary Muscle – the muscular columns
that are located on the inner surface of the ventricles.
7
Q
If blood pressure is too high or low, negative feedback regulation happens. Discuss the negative feedback that happens.
A
- BP is detected by baroreceptors in the carotidartery and/or aorta.
- They send an impulse to the Medulla.
- Medulla interprets that message and sends asignal to the SA Node which increases ordecreases heart rate, lowering or raising CO and BP.
- Vasomotor sends an impulse to the arterioles causing constriction or dilation of vessels to alter BP.
8
Q
Give characteristics of Tunica Media.(Artery)
A
Very thick layer composed of smooth muscle cells and elastic fibers.
9
Q
What is the refractory period?
A
The time following a contraction when a second contraction cannot be triggered.
9
Q
Give characteristics of Tunica Interna. (Artery)
A
Surronds lumen and is composed of a layer of simple squamous.
10
Q
Describe the characteristics of the Atrium
A
- Represent the upper chambers of the heart.
- Separated by the interatrial septum.
- Receives blood (passively) returning to the heart from either the lungs (pulmonary vein) or the body (superior and inferior vena cavae).
- Atria are thin walled chambers.
- Atria are covered by auricles, small pouches on the anterior surface of each atrium used to increase capacity.
- Right atrium receives deoxygenated blood from the superior and inferior vena cavae and the coronary sinus.
- Left atrium – receives oxygenated blood from the pulmonary veins.
10
Q
What are the 3 major arteries?
A
- Aorta- carries blood from the left ventricle to the body.
- Pulmonary arteries – carry blood from the right ventricle to the lungs (via the pulmonary trunk).
- Coronary arteries- carry blood to the myocardium.
10
Q
What are the three structures of the veins?
A
- Tunica Interna– composed of endothelial tissue and a basement membrane.
- Tunica media – very thin layer of smooth muscle (much thinner than the artery).
- Tunica externa– contains elastic and collagen fibers.
10
Q
What are the major role of the arterioles?
A
Perform a major role in regulating blood flow to the capillaries…regulates blood pressure.
11
Q
Discuss the pathway of Cardiac Conduction
A
Sino-artial node
Atrioventricular Node
Bundle of His
Bundle Branch
Purkinje Fibers
Ventricular Depolarization
12
Q
What are 4 major veins?
A
- Superior Vena Cava – brings blood from the head upper limbs.
- Inferior Vena Cava – brings blood from the trunk and lower limbs.
- Coronary Sinus –brings blood from the myocardium. – All the vessels will deposit their blood intro the right atrium.
- Pulmonary Veins – bring blood from the
lungs to the left atrium.
13
Q
Describe Purkinje Fibers
A
- Located within the papillary muscles of the ventricles.
- Conduct the impulse into the mass of ventricular muscle tissue, leading to the contraction of the ventricles.
14
Q
What is cardiac conduction?
A
Specialized cardiac tissue that conducts impulses throughout the myocardium and coordinates the events of the cardiac cycle.
15
Q
What are arteries?
A
- Arteries are large vessels that carry blood away from the heart.
- Carry blood that is high in O2 and low in CO2 (exception: pulmonary artery).
17
Q
What are some characteristics of the Sinoatrial node?
A
- Self-excitatory
- Located on the posterior right atrium
- Generates impulses responsible for the heartbeat (Pacemaker)
- Resting membrane potential of the SA Node ~ 60mV
- Threshold potential of the SA Node ~ -40mV
17
Q
What does vasodilation lead to?
A
Vasodilation
leads to increased blood flow = decreased blood pressure.
18
What is cardiac output?
* Cardiac Output is the volume of blood pumped by either ventricle in one minute.
* Cardiac Output = Heart rate (HR) X Stroke Volume (SV)
19
Discuss the pulomary circuit
Carries blood from the right atrium to the lungs, and back to the left atrium.
20
The friction in peripheral resistance (factor that alter BP) is due to what?
* 1. Blood viscosity – increased viscosity = increased R = increased BP
* 2. Blood vessel length – Increased length = increased R = increased BP
* 3. Blood vessel radius- increased radius = decreased R = decreased BP
21
What are veins?
Thin-walled vessels that carry blood under **low pressure** and high carbon dioxide concentrations.
22
What are the 3 layers of the heart?
– 1. Epicardium – outer layer; protects the heart.
– 2. Myocardium – middle layer; responsible for pumping blood out of the heart chambers.
– 3. Endocardium – smooth inner lining of the heart chambers and valves; contain the Purkinje fibers.
22
What is the difference between lipid-soluble and wate-soluble in capillary exchange diffusion?
* **Lipid-soluble** substances pass directly through the cell membrane.
* ** Water-soluble** substances require assistance to pass the membrane.
24
Describe the capillaries.
* ** Site of exchange:** gases, nutrients, and waste products between blood and tissues.
* Connect arterioles to venules.
* Composed of simple squamous epithelium.
25
What is a P- wave?
Small upward wave
Represents atrial depolarization.
Corresponds with atrial contraction.
26
Describe the tunica externa layer of the artery
outermost layer composed of elastic and collagen fibers.
27
List the three distinct layers of arteries.
1. Tunica interna
2. Tunica media
3. Tunica externa (adventitia)
28
What are factors that alter BP?
1. CO = the volume of blood that is circulating through the body per minute.
2. Blood volume – increase in blood volume increases B.P.
3. Peripheral Resistance – opposition to blood flow due to friction.
29
Discuss the Arterial system.
Arteries carry blood, rich in oxygen, to the body's tissues/system.
30
Discuss the Venous system.
Veins return blood to the heart after gas exchange.
32
Discuss the regulation of blood pressure?
* Neural Regulation: Cardiovascular Centerand vasomotor center are located at the Medulla Oblongata.
* Nerve impulses are sent to the Medulla from 3 areas:
– *Higher Brain Centers*
– *Baroreceptors*- detect changes in stretch.
– *Chemoreceptors* – detect changes in chemical concentration.
33
What would an altered ST segment suggest?
Myocardial infraction (heart attack)
36
Describe Semilunar valves
* Semilunar Valves- regulates blood flow from the ventricles to the arteries.
* – Pulmonary valve: controls blood flow from the right ventricle to the pulmonary artery (pulmonary trunk)
* Aortic valve: controls blood flow from the left ventricle to the aorta.
* – SL valves open when pressure in the ventricles exceeds the pressure in the arteries.
* Valves play a vital role in ensuring blood travels in only one direction (prevents backflow).
* Valves also help to establish a pressure gradient necessary for the cardiac cycle.
37
How are heart sounds created?
* Created from vibrations in heart tissue as blood rapidly changes velocity within the heart.
* First sound, is the result of ventricles contracting and the AV valves closing (lub).
* Second sound, dub, is the result of ventricles relaxing and semilunar valves closing.
38
Describe the tunica interna layer of the artery
* Surrounds lumen and is composed of a layer of simple squamous.
* Attached to a basement membrane.
39
Give characteristics of Tunica Externa. (Artery)
Outermost layer composed of elastic and collagen fibers.
41
What is blood pressure?
The pressure exerted by blood on the wall of a blood vessel.
42
Discuss the systemic circuit.
Vessels that carry blood from the heart to body cells and back to the heart,
43
Define systole and diastole
* Systole – phase of contraction.
* Diastole – phase of relaxation.
45
venules extend from capillaries then merge to form what?
veins
46
What is the QRS complex?
Doward delfection, continues as a large upright triangular wave; ends downward
Represents ventricular depolarization.
Corresponds with ventricular contraction.
47
What do veins do?
* Carry blood toward the heart.
* Carries blood that is high in CO2 and low in O2 (exception: pulmonary veins).
48
Describe cardiac muscle contraction
* RMP = -90mV
* Threshold potential = -70 mV
* Upon hitting threshold, voltage-gated Calcium channels open.
* Ca ion rushes in from the ECF.
* Ca ion channels close
* K+ ion channels open, and K+ rushes out of the cell . . . returning it to resting membrane potential
* Impulses from the S.A. Node spread to the atrial syncytium leading to atrial contraction.
* From the atrial fibers the impulse travels to the AV Node.
* The AV Node receives the impulse and slows the signal.
* From the AV Node the signal travels to the Bundle of His.
* The Right and Left Bundle Branches Carry the impulse downward through the interventricular septum toward the apex, and down to the Purkinje fibers.
* Once the impulse travels down to the Purkinje fibers the impulse then travels down into the mass of ventricular muscle tissue leading to the contraction of the ventricles.
49
Name the three layers of vein structure and give characteristics.
1. Tunica Interna compoased of endothelial tissue and basement membrane.
2. Tunica media very thin layer of smooth muscle
3. Tunica externa contains elastic and collagen.
50
What is stroke volume?
The volume of blood pumped out by aventricle with each contraction.
51
What are arterioles?
Small arteries that deliver blood to the capillaries.
53
Describe the characteristics of ventricles
* Represent the lower chambers of the heart.
* Ventricles have thick, strong walls.
* The left ventricle is thicker than right due to contractile differences.
* Receive blood from the atria and pump blood to the lungs or the body.
* Separated by the interventricular septum.
54
What substances diffuce within capillary exchange?
Substances include oxygen, carbon dioxide, glucose\*, hormones.
56
Describe atrioventricular valves
* Atrioventricular valves (AV valves) separate the atria from the ventricles.
* The tricuspid valve separates the right atrium from the right ventricle.
* The mitral or bicuspid valve separate the left atrium and left ventricle.
57
Vasoconstriction in the arterioles leads to what?
Vasoconstriction
leads to decreased blood flow = increased blood pressure.
58
What is T-wave
Dome-shaped, upward deflection
Represents ventricular repolarization.
Corresponds with ventricular relaxation.
59
What would an enlarged P wave suggest?
Enlargement of an atrium
60
During regulation of blood pressure, Nerve impulses are sent to the Medulla from what 3 areas?
* **Higher Brain Centers**
* ** Baroreceptors**- detect changes in stretch.
* **Chemoreceptors** – detect changes in chemical concentration.
A&P II - Test 1
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