Experiment 7: Cardiac Physiology

The Heart consists of _ pumps in series

2

Blood flow in the heart is ___-directional

Uni

3 Types of Major Cardiac muscle…

Atrial muscle, ventricular muscle, excitatory and conductive muscles

True or False: Cardiac Muscles are not striated

False

Flow of the Heart (Type 1)

1

True or False: If the SA node loses connection the AV node, purkinje fibers will lose its ability to perform an action potential…

True

____ happens at the P wave

Atrial depolarization

____ happens at the Q wave

Initial depolarization of the interventricular septum

____ happens at the R wave

Ventricular depolarization

________ __________ is the highest depolarization because the strongest contraction of the heart is produced here in order to overcome the pressure of the aorta and peripheral resistance

Ventricular depolarization

____ happens at the S wave

Final depolarization

____ happens at the T wave

Ventricular repolarization

True or False: Ventricular depolarization can still occur in the U wave.

True

Cardiac muscle fibers are arranged in a ___________.

latticework

Cardiac muscle contains ______ and _______ filaments.

actin, myosin

Cardiac muscle cells are separated by ___________.

intercalated discs

Ions move in the ICF of cardiac muscle through ___________.

Gap junctions

Cardiac muscle functions as a ___________, enabling a cascade of events.

syncytium

___________ is the key term in determining where electrical signals should start in a normal beating heart.

Sinus rhythm

When the action potential starts in the ___________, it marks the start of blood flow.

AV node

If backflow occurs, deoxygenated blood will return to the ___________ system.

peripheral blood

Specialized Excitatory and conductive systems of the heart flow:

__ Node → __________ pathways → __ Node → ________ → ________ → ________ _______

SA, internodal, AV, bundle of HIs, bundle branches, Purkinje fibers,

True or False: Heart rhythmicity would not have a direct effect on one’s BP and HR

False

Parasympathetic stimulation is distributed mainly to the __ and __ nodes.

SA, AV

___ decreases the rate of rhythm of the __ node and decreases _________ of __ junctional fibers.

Ach, SA, excitability, AV

Ach increases the _________ of fiber membranes to ___________ ions, leading to rapid leakage out and causing ____________

permeability, potassium, hyperpolarization

Sympathetic stimulation increases the rate of __ node discharge.

SA

Sympathetic stimulation increases the _____ ___ _______ and excitability of the cardiac muscle.

rate of conduction

Sympathetic stimulation increases the ___________ of contraction.

force

_____________ stimulates ___________ receptors, increasing membrane permeability to Na+ and Ca²⁺ ions.

Norepinephrine, b1 adregenic

Blood flow through vessels is affected by ___________.

Resistance

The ________ is the pressure exerted by circulating blood on the walls of blood vessels.

Blood pressure

The pressure in arteries during ___________ is typically higher than during ________ .

systole, diastole

___________ is a condition that can result from prolonged high blood pressure.

Hypertension

Factors that can affect blood pressure include ___________, heart rate, and blood volume.

cardiac output

True or False: Air temperature, emotions, body size, medication, and body position can all affect heart rate.

True

_______ __________ __________ is the resistance of the “entire” circulation.

Total peripheral resistance

True or False: PRU is computed by-
Total Pulmonary Vascular Resistance

Total Peripheral Vascular Resistance

False

During late diastole, the ___________ and _______ valves are open.

mitral, tricuspid

During late diastole, the ___________ and ________ valves are closed.

aortic, pulmonic

About __% of the blood that flows into the heart is passive.

70

In late diastole, blood flows into the heart passively from the ___________ and pulmonary _____.

superior and inferior vena cava, veins

In late diastole, there is a rise in ___________ as the __ valve cusps drift toward the closed position.

pressure, AV

Ventricular pressure remains ___________ during late diastole.

low

5 Phases of the Cardiac cycle:
1. ________
2.________
3.________
4.________
5.________

Atrial systole, Isovolumetric ventricular contraction, Ventricular ejection, Isovolumetric ventricular relaxation, Ventricular filling

Atrial systole places the remaining __% of blood into the __________.

30, ventricles

During Atrial systole, there is some ___________ of blood into the veins due to contraction.

regurgitation

True or False: Regurgitation is possible in Atrial systole

True

During Ventricular systole, the __ valves close.

AV

In Ventricular systole, ventricular muscle initially ___________ a little.

shortens

During ___________ _______ ________, intraventricular pressure rises sharply.

Isovolumetric ventricular contraction

True or False: During isovolumetric ventricular contraction, there is ejection of blood.

False

Isovolumetric ventricular contraction lasts _____ sec.

0.05

Aortic pressure during ventricular systole is ___________ mmHg.

80

Pulmonary pressure during ventricular systole is ___________ mmHg.

10

To overcome aortic and pulmonary pressures, the ventricles need to ___________ the pressure rapidly.

increase