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A and P quarter 3 Exam 1
Cardiovascular and Muscular Systems
59
Anatomy
Undergraduate 3
04/05/2011

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Cards

Term
1. Describe the structure and location of the heart.
Definition
The heart has four chambers and is made of cardiac muscle.
Term
3. Describe the differences between the pulmonary and systemic circulation and relate the differences in the structure of the right and left ventricles to the distinctions between these circuits.
Definition
Pulmonary:
Low Pressure System
Rt. Ventricle Pumps De-Oxygenated Blood to Lungs

Systemic: High Pressure System
Left Ventricle Pumps Oxygenated Blood to All Tissues. Left ventricle has thicker muscle because it has to pump blood to more places.
Term
4. Describe the basic structure and function of cardiac muscle. (4)
Definition
1.Highly Oxidative Tissue (prefers lipids as energy source but can use a wide variety of energy sources)

2. Mature Cardiac Muscle cells don’t divide by mitosis: instead hypertrophy occurs when cardiac muscle is damaged.

3. Striated Muscle (sarcomeres found in cardiac muscle) (also short and are capable of branching unlike skeletal muscle, also another difference is they only have one nucleus. They are also interconnected muscle cells which include gap junction which means they communicate and share action potentials)

4. Works as Functional Unit (Syncytium)
Atrial Unit
Ventricular Unit
Term
7. Describe the conduction system of the heart and the functional role of the sinoatrial node as the pacemaker of the heart.(2)
Definition
Sinoatrial Node (SA-Node): Pacemaker Located in the Posterior Wall of the Right Atrium, normally action potential starts here.
Normal path of action potential conduction: SA node→ atrial muscle → AV node→ bundles of His → purkinje fibers → ventricular muscle (contracts from apex to base)
Term
Physiological Properties of Myociardial Cells (6 facts 4 general features)
Definition
1. Contractility: The force of contraction of the heart is dependent on the number of myosin crossbridges bound to actin, and is varied by changing the amount of calcium available to bind to troponin.

2. Excitability (fig 18-12): Heart muscle generates action potentials. The action potential has is longer in duration due to the opening of voltage-gated Ca+2 channels after the opening of voltage gated Na+ channels and prior to opening of voltage gated K+ channels. This longer action potential results in a longer refractory period and prevents the heart from contracting tetanically.

The SA node and conduction tissues each have different action potentials, than cardiac muscle, that are initiated by pacemaker potentials.



3. Automaticity (figure 18-13) Normally only the SA node and the conduction tissues have the ability to depolarize automatically.

4. Conductivity (figures 18.11 and 18.14)

Cardiac muscle cells are connected via gap junctions in the intercalated disks. These gap junctions allow the action potential to move from myocardial cell to myocardial cell in the heart.

Conducting fibers in the heart direct and provide the appropriate timing for the conduction of the action potential in the heart.

Heart is more sensitive to Ca2+ concentration due to Ca2+ being brought in cell from outside of cell and not just from sarcoplasmic reticulum. Due to voltage gated Ca++ channels.
Term
Cardiac Conduction System Features (3) and the normal path of action potential conduction.
Definition
Tissues in the Heart Specialized To Conduct Electrical Impulse (Action Potential) Across the Heart

Sinoatrial Node (SA-Node): Pacemaker Located in the Posterior Wall of the Right Atrium

Atrioventricular Node (AV-Node): Mass of Conducting Fibers Between The Atria And Ventricles

Normal path of action potential conduction: SA node→ atrial muscle → AV node→ bundles of His → purkinje fibers → ventricular muscle
Term
What are ECGs used for? (3)
Definition
Diagnosis of Pacemaker or Conduction Defects; Useful in suggesting Changes in The Muscle Mass of The Heart; Used To Indicate Areas of Ischemia That Occur With Coronary Disease
Term
Numerically Define Brachycardia
Definition
HR < 50
Term
Numerically Define Tachycardia
Definition
HR > 120
Term
Define Premature Beats
Definition
Beats That Originate From a Site Other Than the SA-Node
Term
Define Fibrillations
Definition
Very Rapid Uncoordinated Depolarizations that Produce Uncoordinated Contractions
Term
Which two valves is the second heart sound associated with?
Definition
Pulmonary And Aortic Valves
Term
Define Murmur
Definition
Abnormal Heart Sound
Term
Define systole and list its two phases
Definition
Heart Cycle portion where muscle is contracting

Isovolumetric contraction
Ejection Phase
Term
Define Isovolumetric contraction phase
Definition
Systole Phase: Pressure increases but volume is constant. All valves are closed until ventricular pressures exceed the pressures in the arteries leaving the heart.
Term
Define Ejection Phase
Definition
Begins when the pressures in the arteries increase slightly above the pressures in the aorta and pulmonary artery and the aortic and pulmonary semilunar valves open. Volume in the ventricles decreases during this phase
Term
Diastole definition and two phases
Definition
Heart cycle portion where muscle is relaxed or relaxing

isovolumetric relaxation
filling phase
Term
Define isovolumetric relaxation phase
Definition
begins when pressures in the ventricles decrease below the pressures in the arteries leaving the heart (and the aortic and pulmonary semilunar valves close) This phase continues until the pressures in the ventricles decrease below the atrial pressures. Pressure decreases but volume is constant
Term
Define filling phase
Definition
Begins when the atrioventricular valves open and continues until the next ventricular contraction (and the atrioventricular valves close). Ventricular volume increases.
Term
Define stroke volume
Definition
Volume Pumped Per Beat
Term
Define Cardiac Output (CO)

And write the formula for it
Definition
Amount Of Blood Pumped by Each Ventricle Per Minute (liters/minute)

Stroke Volume (mls/beat) X Heart Rate (beats/min)
Term
What is the formula for MAP?

What is the formula for Estimated MAP?
Definition
(Cardiac Output)(Total Peripheral Resistance)

Diastolic Pressure + 1/3(Pulse Pressure)
Term
What are the three aspects of neuronal control for HR?
Definition
Cardiovascular center in the Medulla Oblongata is the integrating center

Autonomic Nervous System innervates the SA node and AV node (Mechanism of changing HR: Change in Slope of Pacemaker Potential by changing permeability of SA node to ions)

Sympathetic Nervous System (Increases Intrinsic heart rate)

Parasympathetic Nervous System Decreases Intrinsic heart rate (via vagus nerve)
Term
Local Factors that affect HR (3)
Definition
physical fitness, Ions: Ca+2, Na+, and K+ in extracellular fluid, CO2, O2, [H+] also influence smooth muscle in arterioles and change vascular resistance and blood pressure
Term
Define Preload
Definition
The Stretch on the Muscle Fibers before Contraction (Proportional to End Diastolic Volume) The length tension relationship is critical in adjusting the contraction force in the heart with changes in ventricular filling
Term
What is the Frank-Starling Law of the Heart?
Definition
The Greater the End Diastolic Volume the Greater the Force of Contraction (Within Normal Physiological Range)
Term
Define afterload
Definition
The Pressure that the Ventricle Must Exceed Prior To Ejection (Proportional To Aortic Pressure) Increased afterload tends to decrease stoke volume, but other changes compensate for the effects of afterload in a healthy heart
Term
Blood Pressure
Definition
The Driving Force for Tissue Perfusion also the homeostatically controlled variable for the cardiovascular system
Term
Formula for blood flow
Definition
(Arterial Pressure- Venous Press) / Resistance
Term
Define Pulse Pressure
Definition
Systolic Pressure - Diastolic Pressure
Term
What are the three vessel layers and what do they consist of?
Definition
Vessel Layers
1. Tunica Externa
Connective Tissue

2. Tunica Media
Smooth Muscle
Elastic Tissue

3. Tunica Intima
Elastic Fibers
Basement Membrane
Endothelium
Term
What are arteries, and what is their function?
Definition
Strong Elastic Vessels that Carry Blood Away From the Ventricles at High Pressure
(Pressure Reservoir) Primary function is dependent on the presence of a large amount of elastic tissue. Function to store pressure and maintain blood flow throughout the cardiac cycle
Term
What are arterioles and what are their two functions?
Definition
Small Branches of Arteries that lead into Capillaries and Actively Change Diameter: Primary function is dependent on the presence of a lot of smooth muscle which allows the diameter to be varied significantly (Vasoconstriction or Vasodilation). Arterioles Function to 1. Control Blood flow to specific regions by varying the radius and 2. collectively determine the vascular resistance and the MAP
Term
What are capillaries and what is their function?
Definition
Microscopic, Thin Walled Vessels that are Specialized for Exchange between the Blood and Tissues.

Function is related to the presence of only a single layer of cells (endothelium) and a small amount of connective tissue
Term
What determines capillary density?
Definition
Capillary Density Is Proportional To Metabolic Activity of Tissue
Term
What four ways do substances pass through capillary walls?
Definition
Diffusion (lipid soluble substances)
Filtration:
Movement through intercellular clefts (water soluble substances)
Movement through fenestrations (water soluble substances)
Transport via vesicles or caveolae (large substances)
Term
Define venule & give function
Definition
Small Vessel; Transport Blood From Capillaries To Veins
Term
Define vein & give function
Definition
Low Pressure, Thin-Walled Vessels; Function is dependent on the presence of relatively less elastic tissue which makes veins very compliant. Also contain some smooth muscle so that the diameter can be varied somewhat
Term
What are the two functions of the venous system?
Definition
Veins Function to Return Blood to the Heart at low pressure Veins are

Very Compliant (Hold ~70% of Blood Volume at Low Pressure)
Term
What is central venous pressure?
Definition
Pressure in Right Atrium (0-2mmhg)
Term
Define Venous return
Definition
Amount of Blood Returned to the Right Atrium; Directly Effects End Diastolic Volum
Term
What 5 factors determine venous return?
Definition
Blood Volume

Valves

Skeletal Muscle Contraction

Respiratory Movements

Increased Smooth Muscle Tone in Veins (promoted by the Sympathetic Nervous System)
Term
What are the three determinants of total peripheral resistance?
Definition
Length of Blood Vessels: resistance is directly proportional to length

Viscosity of Blood: resistance is directly proportional to viscosity

Radius of Vessels (Arterioles vasoconstrict or vasodilate to change the radius): ! Resistance is proportional to 1/(radius)4 !
Term
What two areas have barorecetpors?
Definition
The aortic arch, the carotid arteries
Term
What are the two hormones used to control bp short term?
Definition
Epinephrine: extension of sympathetic effects
Angiotensin II is a vasoconstrictor which increases resistance or arterioles
Term
4 long term ways of controlling bp
Definition
Increasing Blood Volume → Increases Blood Pressure

Control of Blood Volume (neuroendocrine mechanisms that affect kidney function)

Antidiuretic Hormone (ADH): increases blood volume

Renin Angiotensin System: increases blood volume

Atrial Natriuretic Factor: decreases blood volume
Term
What does the sympathetic nervous system do to affect bloodflow? (2)
Definition
Increase Muscle Blood Flow

Decreases Blood Flow to Skin and Gastrointestinal (GI) Tract
Term
8. Briefly describe the cardiac muscle action potential with respect to the changes in membrane potential
Definition
Na+ comes in, Ca++ comes in, then K+ out

Ca++ voltage gated channels
Term
9. Describe how the atria and ventricles act as functional units (2)
Definition
They both have separate nodes, atria pump first

Atrium cells and Ventricle cells do not have gap junctions between them and do not communicate with each other
Term
List the events of the cardiac cycle and describe how these events are related (8)
Definition
Blood in from vena cavae

P-Wave: Atrial Depolarization

Atria pump

Blood to right and left ventricles

QRS-Complex: Ventricular Depolarization

Atria relax, but masked by QRS

Blood pumped to lungs and rest of the body from ventricles

T-Wave: Ventricular Repolarization

Ventricles relax
Term
Formula for Max HR
Definition
220 bpm minus age
Term
Describe how mean arterial pressure is homeostatically controlled to regulate the overall function of the cardiovascular system
Definition
When blood pressure is increased or decreased, tissue perfusion is affected relatively, and heart rate is adjusted inversely
Term
Describe how blood pressure generally changes as the blood moves from the ventricle through capillaries and into veins (2)
Definition
Ventricle pressure increases to just above aortic pressure

Pressure decreases with each decrease in size of arteries or veins
Term
What does increased venous pressure lead to?

What does a lower number of plasma proteins lead to?
Definition
Increase in [lymph] fluid accumulation

Less osmotic pressure which leads to edema
Term
What causes for the Net Movement of fluid from the Blood into the Interstitial Fluid?
Definition
a Balance of Hydrostatic Pressures and Osmotic Pressures between the capillary and intercellular space
Term
Why is low pressure in the veins a good thing?
Definition
So that capillary flow moves from arteries to veins, also why venous system has more blood (60%)
Term
Explain how vascular resistance is regulated by the autonomic nervous system (5)
Definition
Baroreceptors sense pressure, send signals to

Medulla Oblongata - integrating center, interprets baroreceptor signals

Effectors: Heart, Arterioles and Veins

Sympathetic Nervous System: Promotes Vasoconstriction of arterioles in most areas; increases heart function and increases venomotor tone (venous stiffness)

Parasympathetic Nervous System: Promotes Vasodilation in a Few Areas but is not important in influencing total peripheral resistance; reduces heart rate
Term
Describe the baroreceptor reflex and explain its significance in blood pressure regulation (5)
Definition
Mechanoreceptor measures stretch of arteries

Stimulates cardioacceleeratory center, inhibit cardioinhibitory center, and stimulate vasomotor center.

This results in vasomotor constriction increasing peripheral resistance, sympathetic impulses lead to heart rate increase, contractility and cardiac output increase.
Term
Describe how cardiac output, vascular resistance, MAP and blood flow change during exercise
Definition
CO up
VR up
MAP up
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