Chapter 19

Question 1

Pulmonary circuit

Answer 1

Right side receives blood that has circulated through the body

Question 2

Systemic circuit

Answer 2

Left side blood leaves it by way of another large artery aorta

Question 3

Heart

Answer 3

With then mediastinum between two lungs more than half the heart is to the left of the bodies median plane

Question 4

Pericardium

Answer 4

Isolates heart from other thoracic organs allows room to expand

Question 5

Function of pericardial fluid

Answer 5

Lubricates the membranes and allows the heart to beat within minimal friction

Question 6

Fibrous skeleton

Answer 6

Tissue concentrated in the walls between the heart chambers

Question 7

Functions of fibrous skeleton

Answer 7

Provide structural support for the heart

Anchors the cardio sites and gives them something to pull against

Serves as electrical insulation between the arteria and the ventricles

Question 8

Heart valves

Answer 8

To pump blood affectively to ensure a one-way flow

Question 9

What closes the semi lunar valve’s

Answer 9

Changes in blood pressure that occur as a heart chambers contract and relax

Question 10

Pathway of blood through the heart

Answer 10

Enters the right atrium from the superior and inferior venae cavae

Blood entering right atrium is oxygen poor

Flows from the right atrium through the right AV

Into the right ventricle through the pulmonary valve and exit through the pulmonary trunk

Pulmonary trunk splits into pulmonary arteries they carry blood to lungs where CO2 is unloaded and 02 is loaded

Blood is return to heart by vena cava

Blood enters the left atrium oxygen is Rich

Through the left AV valve into left ventricle then through the aortic valve and exits through ascending aorta

Now blood is in systemic circulation 02 will be unloaded and CO2 will be loaded

After gas exchange blood will be returned to the right atrium by superior and inferior vena cava

Question 11

Where does the coronary sinus empty into

Answer 11

Empties blood into the right atrium

Question 12

Myocardial infarction

Answer 12

A heart attack caused by a fatty deposit or blood clot in a coronary artery

Question 13

Arterial anastomoses

Answer 13

Where two arteries come together and combined their blood flow to points farther down stream

Question 14

Collateral circulation

Answer 14

The route points take that supply the heart tissue with blood if the primary route becomes obstructed

Question 15

Autorhythmic

Answer 15

Doesn’t depend on nervous system for its rhythm heart has its own pace maker and electrical system

Question 16

Cardiocyte

Answer 16

Short thick branched cells

Question 17

Where are calcium ions admitted from to activate muscle contractions

Answer 17

T tubules admit calcium ions from the extracellular fluid

Question 18

What is unique about the mitochondria

Answer 18

Large

Question 19

Intercalated discs

Answer 19

Cardiocytes joined end to end by thick connections

Question 20

Electrical junction

Answer 20

Form channels that allow ions to flow from the cytoplasm of one cardiocyte directly into the next

Question 21

How is damaged cardiac muscle repaired

Answer 21

No satellite cells so repair is almost entirely by fibrosis

Question 22

Why is cardiac muscle so vulnerable to oxygen deficiency

Answer 22

Cardiac muscle depends almost exclusively on aerobic respiration to make ATP

Question 23

Is cardiac muscle prone to fatigue

Answer 23

No

Question 24

Sympathetic fibers innervate which part of the heart

Answer 24

SA and AV node

Question 25

Affects sympathetic innervation has on the heart

Answer 25

Control of contraction strength Increases heart rate

Question 26

What cranial nerves do parasympathetic fibers travel to the heart

Answer 26

Vagus nerves in the medulla oblongata

Question 27

Parasympathetic fibers innervate which part of the heart

Answer 27

Synapse with postganglionic neuron's in the epicardial surface and within the heart wall

Question 28

Main effect of parasympathetic innervation

Answer 28

Reduce heart rate

Question 29

Sequence of conduction

Answer 29

SA node pacemaker that initiates each heartbeat and determines the heart rate Signals from the SA node spread throughout the atria AV node acts as an electrical gateway to ventricles fiber skeleton acts as an insulator to prevent currents from getting to ventricles AV bundle is pathway by which signals leave AV node Purkinje fibers are nerve like and distribute the electrical excitation to cardiocytes of the ventricles

Question 30

Sinus rhythm

Answer 30

Normal heartbeat triggered by the SA node

Question 31

Pacemaker potential

Answer 31

Cells of the SA node slowly drift upward showing a gradual depolarization

Question 32

Cardiac muscle duration

Answer 32

Long duration for action potential contraction and absolute refractory period

Question 33

Skeletal muscle duration

Answer 33

Short action potential contraction absolute refractory period

Question 34

Pressure in the atria and ventricles during ventricular filling

Answer 34

Ventricles expand pressure drops below that of the atria AV valves open blood flows into ventricles causing ventricular pressure to rise and atrial to fall

Question 35

Pressure in the atria and ventricles during ejection

Answer 35

Ventricular pressure exceeds arterial pressure and forces semi lunar valves open

Question 36

Dicrotic notch

Answer 36

Ventricular diastole blood from the aorta and pulmonary trunk briefly flow through the semi lunar valve's Backflow quickly fills creating a slight pressure rebound that appears as the notch of the aortic pressure curve

Question 37

Stroke volume

Answer 37

Amount of blood each ventricle ejects about 70

Question 38

End diastolic volume

Answer 38

At the end of ventricular filling each ventricle contains an EDV of about 130 mL of blood

Question 39

End systolic volume

Answer 39

Blood remaining behind in ventricles

Question 40

Cardiac output

Answer 40

Amount of blood ejected by each ventricle

Question 41

Heart rate

Answer 41

Counting the number of pulses in 15 seconds multiply by four to get beats per minute

Question 42

Positive inotropic agents

Answer 42

Raises heart rate

Question 43

Negative inotropic Agents

Answer 43

Lowers heart rate

Question 44

Cardiac reserve

Answer 44

Difference between maximum and resting cardiac output

Question 45

Preload

Answer 45

Amount of tension in the ventricular myocardium immediately before it begins to contract

Question 46

Frank starling law of the heart

Answer 46

The more the ventricles are stretched The harder they contract on the next beat

Question 47

Contractility

Answer 47

How hard the myocardium contracts for a given preload cardio sites more responsive to stimulation

Question 48

How do positive negative inotropic agents affect contractility

Answer 48

Positive increases contractility negative decreases

Question 49

What is afterload

Answer 49

Sum of all forces a ventricle must overcome before it can Eject blood blood-pressure opposes the opening of these valves and thus limits stroke volume