12. Be able to describe the properties of cardiac action potentials and contrast those properties to skeletal muscle.

1. Rapid Depolarization: A) reaches theshold, voltage gates sodium open. B) Influx NA+ C) depolarization 2. Plateau: a) membrane potential reaches + 30mv b) Sodium channels close c) Na+ pumped out d) calcium channels open e) calcium pumped in 3. Repolarization: a) calcium channels close b) potassium channels open c) potassium rushes out D) negative charge restored Contrast: Heart muscles are self excitable and can start there own depolarization Skeletal Muscle impulses do not spread cell to cell, cardiac muscle functions as a whole unit Refractory period for cardiac muscle is longer than skeletal. Also cardiac muscle involved the exchange of calcium rather than potassium.

The Cardiovascular System Flashcards by Amanda Wollard

Arteries carry blood?

Away from heart (efferent vessels) think exit

The blood is oxygenated

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Veins carry blood?

Towards Heart (afferent vessels)

The blood is deoxygenated

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What are the 4 chambers of the heart?

R/L Atria

2. R/L Ventricles

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Flow of Blood to the Heart?

Superior and inferior vena cava
Right Atrium
Right AV Valve
Right Ventricle
Pulmonary Valve
Pulmonary Trunk
Pulmonary Artery
Pulmonary Vein
Left Atrium
Left A.V. Valve
Left Ventricle
Aortic Valve
Ascending Aorta
Aortic Arch
Descending Aorta

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Location and Size of the heart

Lies In Mediastinum, the middle of the thorax.

Approximate dimensions are 12 cm long, 9cm wide and 6cm deep.

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Describe the Pericardium

A loose fitting inextensible sac. Lines the heart. Consist of 2 parts: fibrous and serous portion. Sac is tough white fibrous tissue lines with smooth moist serous membrane.

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Trace Coronary Circulation

Ascending Aorta
R Coronary Artery posterior interventricular –> Antrioventricular nodal Artery-> posterior septal Artery
Marginal Artery—>acute marginal Artery

Ascending Aorta
L coronary Artery
Anterior Interventricular branch–> anterior septal Artery
Circumflex branch—> anterior and posterior ventricular branches

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Be able to explain what leads to coronary artery disease?

The reduce of blood flow to the vital myocardial tissue.

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How does Coronary Artery disease relate to angina and ischemia

The coronary arteries are unable to supply enough blood and oxygen to the heart muscle (myocardium). This can be caused by fatty deposits in the Artery to reduce blood supply.

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Be able to describe and/or identify the features and functions of each of the heart’s chambers.

Atria: 2 chambers separated by the interatial septum. Often called receiving chamber because they receive blood from the veins (return Blood to heart) by relaxing and contracting. It also pushes the blood into the lower chambers

Ventricles: 2 lower chambers of the heart separated by interventricular septum. Known as the pumping chamber of the heart because they receive blood from the atria and pump blood out of the heart into the arteries.

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Be able to describe the events of the cardiac cycle.

Atrial Systole:
•begins with P wave of the ECG- triggers atrial contraction
•Contraction of atria creates pressure gradient that pushes blood out of atria into the relaxed ventricles
• Because of gradient AV valves are open; SL valves are closed
• Ventricles are relaxed filling with blood from atria
Isovolumetric venticular contraction-
• onset of ventricular systole coincides with R wave of ECG & appearence of 1st heart sound
• Occurs between start of ventricular systole and opening of SL valves
• Ventricle volume remains constant pressure increases rapidly
- intraventricular pressure rises enough to close AV Valve produces 1st heart sound
- pressure is not high enough to open SL valves
Ejection
• SL valves open and blood is ejected from ventricles when the IV pressure exceeds the pressure in the pulmonary artery and Aorta
• Rapid Ejection- initial short phase characterized by a marked increase in ventricular and aortic pressure and in aortic blood flow
• Reduced ejection: characterized by less abrupt decrease in ventricular volume; coincides with the T wave of the ECG
Isovolumetric ventricular relaxation
• Ventricular diastole begins
• occurs between closure of SL valves and opening of AV valves
• A dramatic fall in intraventricular pressure but not enough to open AV valves, thus no change in volume
•2nd heart sound heard
Passive Ventricle Filling
• continued ventricular relaxation reduces intraventricular pressure and returning venous blood increases intraatrial pressure, produces enough pressure to open AV valves
• blood rushes into relaxing ventricles
• Diastis later longer period of slow ventricular diastole

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Define the Cause of S1 and S2

S1: primarily caused by contraction of ventricles and by vibration of closing AV Valves

S2: Vibrations of closing SL valves

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Be able to trace an electrical impulse through the conducting system and explain the relationship to the cardiac cycle.

The signal is initiated by SA node (pacemaker) and spreads to the rest of the right atrial myocardium directly, to the left atrial myocardium by way of a bundle of interatrial conducting fibers and AV node by three intermodal bundles. The AV nose then initiates a signal that is conducted through the ventricular myocardium by way of the AV bundle and subendocardial branches (Purkinje Fibers).

Relationship: Heart Beat

SA node→ atrial muscle → AV node→ bundles of His → purkinje fibers → ventricular muscle (contracts from apex to base

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Be able to describe the properties of cardiac action potentials and contrast those properties to skeletal muscle.

Rapid Depolarization: A) reaches theshold, voltage gates sodium open. B) Influx NA+ C) depolarization
Plateau: a) membrane potential reaches + 30mv b) Sodium channels close c) Na+ pumped out d) calcium channels open e) calcium pumped in
Repolarization: a) calcium channels close b) potassium channels open c) potassium rushes out D) negative charge restored

Contrast:
Heart muscles are self excitable and can start there own depolarization

Skeletal Muscle impulses do not spread cell to cell, cardiac muscle functions as a whole unit

Refractory period for cardiac muscle is longer than skeletal. Also cardiac muscle involved the exchange of calcium rather than potassium.

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Volume of blood pumped by one Ventricle per minute

Cardiac output

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Amount of blood that is ejected from the ventricles of the heart with each beat

Stroke Volume

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Be able to describe the influence of the autonomic nervous system on the conduction system and heart rate.

Both divisions of Autonomic Nervous System send fibers to the heart. They increase the heart rate by stimulating the SA Nodes (Pacemaker)

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The rate at which the heart beats

Heart Rate

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describe end-diastolic volume the factors that influence it

Endiastolic - the amount of blood in ventricles when full

Influenced by preload. Increased increases EDV and Decreased decreases EDV

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describe end-systolic volume and the factors that influence it

The amount of blood left behind after Ventricle contracts

Contractility and afterload
Increased contractility decreases ESV, which increases SV
Increased afterload, increases ESV, which decreases SV

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How do you calculate cardiac output

CO= HR (Heart Rate) x SV (Stroke Volume)

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Causes a Myocardial Infarction

The reduce of blood flow to the vital myocardial tissue. Blood cannot pass through the occluded vessel and so cannot reach the heart muscle cells it normally supplies. Deprived of oxygen they sell soon die or are damaged.

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Causes of heart murmur

Incomplete closing of valves or the construction or narrowing(stenosis) of them

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Relationship between coronary artery disease, myocardial infarction, and arrhythmia

All have to do with the reduced blood flow to heart

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The phase of heart contraction is called

Systole

the phase of relaxation is called .

Diastole

pathway for conduction of an action potential through the heart?

SA node, AV node, AV bundle, bundle branches, Purkinje fibers

Which of the following would increase stroke volume?

Increased Ca2+ in the interstitial fluid, Epinephrine, Increase in venous return

indicates ventricular repolarization

T wave

represents the time from the beginning of ventricular depolarization to the end of ventricular repolarization

Q-T interval

represents atrial depolarization

P wave

represents the time when the ventricular contractile fibers are fully depolarized; occurs during the plateau phase of the action potential

S-T segment

represents the onset of ventriculat depolarization

QRS complex

represents the conduction time from the beginning of atrial excitation to the beginning of ventricular excitation

P-Q interval

describe what is represented by the colors blue and red.

Blue is usually veins and means that it is deoxygenated except in the pulmonary circuit veins are red Red means that the blood is oxygenated usually are the color of arteries except in the pulmonary circuit

Function of capillaries?

Bring nutrients and oxygen to tissues and remove waste products

Be able to explain why valves are found only in veins.

The pressure in the veins are very low compared to the arteries. This is why Veins need valves in order to prevent the back flow of blood. The arteries do not need valves due to the amount of pressure used to push the blood through.

What causes varicose veins

Varicose veins are caused by weakened valves and veins in your legs. Normally, one-way valves in your veins keep blood flowing from your legs up toward your heart. When these valves do not work as they should, blood collects in your legs, and pressure builds up. The veins become weak, large, and twiste

movement of blood through a vessel, tissue, or organ, and is usually expressed in terms of volume of blood per unit of time.

Blood flow

force exerted by a fluid due to gravitational pull, usually against the wall of the container in which it is locate

Hydrostatic pressure

What are two mechanisms used to return blood back to the heart?

Respiratory Pump mechanism- pressure changes occur in the thoracic and abdominal cavities during inspiration and expiration. This compresses veins and assists blood return to the heart. The muscle pump mechanism- muscular contractions compress the veins, squeezing blood back towards the heart. Pocket valves inside the veins prevent the back-flow of blood returning to the heart.

Calculate Mean Arterial Pressure

(2 x diastolic BP) + systolic BP/3

Prevent back flow into the atria

Atrioventricular Valves

Prevents backflow into ventricles

Semilunar Valves

Quivering atria

Atrial fibulation

Fast Heart Rate

Tachycardia

Slow Heart Rate

Bradycardia

Calculate Stroke Volume

EDV-ESV

Baroreceptor Reflux: High BP

1. Stimulate Baroreceptors 2. Cardioinhibitory center turned on, vasomotor turned off, cardioaccelatory center turned off -->Heart Rate decreased 3. Decrease cardiac output 4. Homeostasis Restored

Baroreceptor reflux: Low BP

1. Stimulate Baroreceptors 2 Cardioaccelatory stimulated, cardio inhibitory inhibited, vasomotor stimulated --> increase HR 3. Increase cardiac output -vasoconstriction occurs 4. Homeostasis restored

Chemo Reflux

1. Increase CO2, decrease PH and O2 2. Chemoreceptors stimulated 3. Respiratory centers stimulated 4. Respiratory Rate increases

Natriuretic Peptides: BP too high

1. NP released by heart 2. Increase Na+ in urine, increase water loss in urine, reduce thirst, inhibit ADH, aldosterone, epinephrine and Neuro epinephrine, peripheral vasodilation 3. Decrease blood volume, decrease blood pressure 4. Homeostasis restored

Natriuretic Peptides: BP too low

1. Kidneys Secrete EPO 2. Makes blood cells 3. Blood Volume rises 4 BP rises OR 1. Kidneys release Renin 2. Widespread vasoconstriction, Antidiuretic Hormone released, aldosterone secreted , thirst stimulated 3. Increase BP and Blood Volume

Conducts blood flow from the heart (left Ventricle) through the blood vessels to all parts of the body (except the gas-exchange tissues in the lungs) and back to the heart.

Systematic Circuit

Exchange of gases between blood and air takes place, converting deoxygenated blood to oxygenated blood. This oxygenated blood then flows on through lung venues into 4 pulmonary veins and returns to the left Atrium of the heart. From the left Atrium it enters the left ventricle to be pumped again through the systematic Circuit.

Pulmonary Circuit

Largest Artery in the body

Aorta

Largest veins in the body

Superior and Inferior Vena Cava

What is the average blood pressure?

100 mg Hg to 35 mg Hg 120/80

Heart Rate is adjusted by

autonomic nervous system, hormones

Stroke Volume is adjusted by

changes in EDV and ESV

What does the sympathetic division do to the heart

Accelerate

What does the parasympathetic division (ACH) do to the heart

Slows it down

Decreases in heart rate

Cardioinhibitory center

Increases heart rate

Cardioacceletory center

Which blood vessels that present the greatest resistance to bloodflow

Arterioles

What is the primary determinants of arterial blood pressure

Cardiac output and peripheral resistance

What mechanisms control peripheral resistance

Blood viscosity and diameter of arterioles

Muscles in walls of arteriole making strict vessel or dolly for sought this changing the diameter of the arteriole

Vasomotor mechanism

Blood flow through capillary bed

1. Elastic Artery 2. Muscular Artery 3. Arteriole 4. Capillary bed 5. Venule 6. Medium-size Vein 7. Large Vein

What are the two types of capillaries?

Continuous and fenestrated

This type of capillary has pours

Fenestrated

What is Preload?

Degree of stretch?

What is the Starling's Principle?

More Blood goes on, more blood comes out

The amount of tension the contracting ventricles must produce to force open the semilunar valves

Afterload

Positive Factor Contractility: Sympathetic Division

``` Epinephrine binds to beta cells in cardiac muscle Stimulates cAMP cAMP release calcium More calcium--> more cross bridge cycles Strong contraction ```

Negative Factor Contractility: parasympathetic division

Stimulate vagus nerve Acetylcholine binds to beta receptor Inhibitory effect- decrease calcium- decrease force

Thyroid Hormone Contractility

Increase Metabolism | More ATP: faster cross bridge cycles, strong contraction

A bulge in a weak area of the artery caused by the pressure of the blood inside the vessel, something like a bulge in an over-inflated inner tube.

Aneurysm

A thickening and toughening of arterial walls

Arteriosclerosis

the blockage or closing of a blood vessel or hollow organ.

Occlusion

an escape of blood from a ruptured blood vessel, especially when profuse.

Hemorrhage

Marfans Syndrome

Effects the bodies connective tissues can effect other features of the body such as the heart to cause aortic enlargement expansion of the main blood vessel that carries blood away from the heart to the rest of the body)

The Cardiovascular System Flashcards

(82 cards)