RESP1193 Cardio A&P Chapter 17, Functional Antomy of the Cardiovascular System

Mediastinum behind the sternum

location of the heart

Apex

lower tip of the heart

Base

the top end of the heart where the great vessels are located

Point of maximal Impact (PMI)

this is created by the repeated impact of the heartbeat on the inner chest wall.

Apical Beat

another term for PMI

The 5th intercostal space

Where is PMI typically felt

Shift the heart to the left

How will a right lung pneumothorax affect the heart?

Pericardium

Loose fitting membranous sac which covers the heart

fibrous pericardium

Tough, superficial most portion of pericardium

Parietal Pericardium

Lines the inner surface of the fibrous pericardium

Visceral pericardium (epicardium)

innermost layer of pericardium directly adhered to the hearts surface

epicardium (visceral pericardium), myocardium, endocardium

Name the 3 components of the heart wall from most superficial to most deep.

cardiac muscle

what is myocardium?

right atrium

heart chamber that receives deoxygenated blood from the vena cava and coronary sinus

Tricuspid Valve

Blood flows from the right atria to the right ventricle via this structure

The pulmonary artery

The right ventricle pumps deoxygenated blood into...

Semilunar Valves

Valves that are closed during ventricular diastole

atrioventricular valves (AV)

valves that are open during ventricular diastole

atrioventricular valves

valves that are closed during ventricular systole

Semilunar Valves (SV)

valves that are open during ventricular systole

left atrium

heart chamber that receives oxygenated blood from the 4 pulmonary veins

bicuspid (mitral) valve

blood flows from the left atrium to the left ventricle thru this structure

Pulmonary artery, Aorta

where are the semi-lunar vales located?

atrioventricular valves

structure that prevents backflow of blood into the atria during ventricular systole

interatrial septum

structure that separates the two atria, preventing the mixture of oxygenated and deoxygenated blood

semilunar valves

structure that prevents backflow of blood into the ventricles during atrial systole.

interventricular septum

structure that separates the right and left ventricles preventing the mixture of oxygenated and deoxygenated blood.

papillary muscles

cone shaped pillars which attach to the chordae tendinae

Chordae Tendinae

strong connective tissue strings that attach to the AV valves allowing them to open and close

Fibrous annuli

tough set of connected rings that form a semi-rigid framework to which the heart valves and and cardiac muscle are attached

Apex, Base

blood stroke volume is squeezed from _________ to __________

the right and left coronary arteries

Where does the myocardium itself receive it's blood supply from?

right coronary artery

which coronary artery is the dominant blood supplier in the coronary circulation

FALSE: there is a lack of collateral circulation between the coronary arteries; if one becomes blocked, there are few detours the blood flow can take.

True or False: There is an abundance of collateral circulation between the coronary arteries.

Ischemia, Angina Pectoris

potential consequences of occluded coronary blood flow

ischemia (tissue hypoxia)

decreased oxygen supply to the heart

angina pectoris

central chest pain caused by occluded coronary blood flow

myocardial infarction

heart muscle tissue death caused by tissue hypoxia

True

True or False: Coronary veins flow parallel to coronary arteries

Coronary sinus (right atrium)

where does 75% of the coronary venous drainage empty

All four; contributing to normal anatomical shunt

which heart chamber(s) do Thesbian (coronary) veins empty into?

70%

how much oxygen does the myocardium extract from it's arterial blood?

Exercise increases myocardial oxygen requirements, thus increasing coronary blood flow

how does exercise affect myocardial oxygen needs?

myocardial oxygen needs

what factor governs coronary blood flow?

ventricular diastole

coronary blood flow only occurs during which phase of heartbeat?

4-5%

coronary blood is what percent of total cardiac output?

TRUE: this momentarily stops coronary blood flow during ventricular systole.

True or False: During systole, the ventricles compress the coronary blood vessels.

shortens diastolic time

effect of extreme tachycardia on diastolic time

1. decreased coronary blood flow

2. decreased end diastolic volume

3. Decreased ejected stroke volume

name 3 effects of a shortened diastolic time

Stroke volume (SV)

the volume of blood ejected by a ventricle with each heartbeat

Cardiac Output (CO)

measurement of the amount of blood ejected per minute from either ventricle of the heart

to conduct electrical impulses to stimulate rhythmic, synchronized myocardial contractions.

Purpose of the cardiac conduction system

SA node

AV node

Bundle of His

Right/Left Bundle Branches

Purkinje Fibers

List the order of impulse conduction in the cardiac conduction system

sinoatrial (SA) node

"Pacemaker" that initiates electrical impulses of the heart

Bundle of His (AV bundle)

this structure is the only connection of action potential between the atria and ventricles

Right/Left Bundle branches

this structure conducts the electrical impulse to the right/left ventricles via the interventricular septum

Purkinje fibers

subdivision of bundle branches throughout the right and left ventricular myocardium

Beta 1 receptors

Sympathetic receptors that increase heart rate and contractility are?

decrease heart rate and contractility

Effect of parasympathetic fibers on SA and AV nodes

myocyte

muscle fiber cell bounded by the sarcolemma

Sarcolemma

muscle cell membrane

T tubules

deep dipping of sarcolemma into the cells interior allowing electrical impulses to travel deep inside the muscle cell

sarcoplasmic reticulum

intracellular network of tubules throughout the muscle fiber that store calcium

Calcium is released from the sarcoplasmic reticulum

what happens when electrical impulses within the t-tubule stimulate adjacent sarcoplasmic reticulum

Cardiac Cycle (one heart beat)

A complete heartbeat consisting of contraction (systole) and relaxation (diastole) of both atria and both ventricles

ventricular filling

Preload is defined by

preload is 80% passive and 20% active (atrial kick)

what percent of ventricular filling (preload) is active, and passive?

isovolumetric contraction

brief period during ventricular emptying when all valves are closed before blood is ejected from the ventricles

afterload

the amount of resistance to ejection of blood from the ventricle

End Diastolic Volume (EDV)

volume of blood in each ventricle at end of ventricular diastole (PRELOAD)

Ejection fraction

the filled ventricles normally eject about 60% EDV. This is known as...

CO= HR x SV

cardiac output formula

decreased stroke volume

an increased afterload would have what effect on stroke volume?

dichrotic notch

"shock wave" from forceful closure of semilunar valves on the arterial pressure waveform

Frank-Starling Mechanism

venous blood return to the right atrium determines overall cardiac output. what is this concept?

increased blood flow

increased ventricular filling

increased muscle fiber distension

increased force of contraction

Explain the mechanics of the Frank-Starling Mechanism

Drugs, Exercise, Anxiety

name 3 sympathetic stimuli that regulate pumping activity

Respiratory vagal stimulation

name a parasympathetic regulator of pumping activity

increased cardiac output

effect of increased heart rate on cardiac output

the hearts pumping action; elastic recoil of the arteries

what are the 2 forces responsible for perfusion pressure?

systemic arterioles

these structures can form precapillary sphincters that can constrict or dilate

constrict

at rest, precapillary sphincters will ___________

the arteries will dilate to increase perfusion in order to meet increased tissue oxygen needs.

what happens to arteries in hypoxia, where PaCO2 is increased and pH is decreased (acidosis)

vasoconstriction

contrary to systemic arteries, hypoxia in the pulmonary artery will cause ___________

veins; contain 64% of blood volume

vessels that contain the greatest proportion of blood volume at a given time due to high distensibility

skeletal muscle milking

sympathetic venous constriction

cardiac pumping action

subatmospheric intrathoracic pressure during breathing

name 4 factors that augment (increase) venous return

high, low

in arteries, blood flows from ________ to

__________ pressure areas

P(systolic) - P(diastolic)

pulse pressure formula

{P(syst) + 2(Pdiast)]/3

Mean Arterial Pressure Formula

FALSE: Heart is in diastole 2/3 of the time; Systole is only 1/3 of the time.

True or False: Heart remains in systole longer than diastole

Lowest, Highest

Systolic pressure in the vena cava reads the ________; Sytolic pressure in the aorta reads the ___________.

increase vascular resistance

how will a decrease in the area of a vascular bed affect vascular resistance?

capillaries

what vessel does gas exchange occur in?

-Stroke Volume

-Arterial Compliance (elasticity/recoil force)

-Arterial Resistance (vessel diameter)

name the 3 factors that determine Mean Arterial Pressure

P(syst) > 135-140mmHg; P(diast) > 90mmHg

what are the systolic and diastolic pressures that characterize hypertension?

-increased workload to heart >>> heart failure

-Cerebral Vascular Accident (CVA)

-Renal Hemmorrhages

name 3 detrimental effects of hypertension

because blood from all systemic veins flows into the right atrium; thus anything that affects RAP affects all venous pressures in the body.

why is right atrial pressure (RAP) known as "central venous pressure (CVA)?"

-the hearts ability to pump blood out

-rate of blood return to the vena cava

name the 2 factors of that the determine RAP (Right Atrial Pressure)

JVD (jugular vein distention)

Hepatomegaly (enlarged liver)

Pedal (peripheral) edema

a RAP greater than 6 mmHg can cause

0-6 mmHg; RAP/CVP

what is the ventricular pressure value for RVEDP; what is used to measure it?