PHYS E2

E2

Located in the R atrium, near opening of SVC

Sinoatrial (SA) Node

Passes signal from SA node to the R atrium

Internodal pathways

Passes signal from the SA node to the L atrium

Bachmann’s Bundle

Passes signal from atria to ventricles

Atrioventricular AV Node

Passes signal from AV node to bundle branches

Bundle of His

Passes signal from bundle of HIS to Purkinje fibers

Left/Right Bundle Branches

Passes signal to R and L ventricles

Purkinje Fibers

What area in the cardiac conduct has the highest conduction velocity **ANSWER,** because it has to make sure the whole myocardium contracts at the same time

Purkinje Fibers

What area has the slowest conduction velocity, **Answer,** because you want the atrium to fully contract before the ventricles contract

AV Node

Phase 0 of the Action Potential of the pacemaker cells, and channels open

depolarization and LTCC open (L-type Calcium channels)

Phase 3 of the action potential of the pacemaker cells, and channels open

repolarization K+ open

Phase 4 of the action potential of the pacemaker cells, channels open/Closed (**PART 1)**

Funny Na channels open, K close

Phase 4 of the action potential of the pacemaker cells, channels open/Closed (**PART 2)**

Transient T-Type Calcium channels open and you go back to phase 0 after reaching threshold

Phase 4 of the action potential of the pacemaker cells is considered the **What potential**

Pacemaker Potential

Firing rate of SA node

60-100

Firing rate of the AV node

40-60

Firing rate of the Purkinje

20-40

Rate of firing equals

Heart rate

The highest rate of nodes regulates heart rate, what is the descending order of set pace for pacemakers

SA to AV to Purkinje

Phase 4 of the ventricular myocyte action potential

complete depolarization NA/K pump and K channels

Phase 0 of the ventricular myocyte action potential

Sodium influx, depolarization

Phase 1 of the ventricular myocyte action potential

K+ efflux, slight repolarization

Phase 2 of the ventricular myocyte action potential

plateau because of LTCC opens

Phase 3 of the ventricular myocyte action potential

K+ efflux

What is Ca used for in cardio myocytes

maintains plateau

P wave of EKG (first little hump)

Atrial depolarization

QRS complex (Large Spike)

Ventricular depolarization

T wave ( broader wave)

ventricular repolarization

(EKG NOT A SPIKE) the flat line between the P-wave and the QRS tells you the time delay between atrial and ventricular activation (AV node activity)

PR segment

(EKG NOT A SPIKE) distance of the beginning P-wave to the beginning of the QRS, tells you the time interval from the onset of the atrial activation to the onset of ventricular activation

PR Interval

(EKG NOT A SPIKE) the time between QRS and T wave- tells you the time between ventricular depolarization and repolarization

ST segment

(EKG NOT A SPIKE) length of ventricular depolarization and repolarization (beginning of QRS to the end of the T wave)

QT interval

Relationship between EKG and Ventricular Myocyte action potential- Phase 0

QRS

Relationship between EKG and Ventricular Myocyte action potential-Phase 2

St- segment

Relationship between EKG and Ventricular Myocyte action potential- Phase 3

T Wave

SCV and IVC bring de-oxygenated blood into the

Right atrium

After the right atrium the blood enters the **ANSWER** through the tricuspid valve

Right Ventricle

After the right ventricle the Blood enters the **ANSWER** to the **ANSWER**

Pulmonary valve, Pulmonary artery

After the lung the blood returns in the **ANSWER** to the

left atrium

After the blood enters the left atrium blood enters through the **NASWER** valve into

Mitral valve into the left ventricle

After the left left ventricle the blood exits via the

Aorta

The purpose of valves is to ensure

one way blood flow

The purpose of **Answer** is to ensure the AV valves are closed and blood does not back flow into the atria

Chordae tendinea

AV valves open when pressure is higher in the **ANSWER** than in the ventricle to ensure one way flow

Atrium

You have an aortic and pulmonary **ANSWER** and it opens passively when ventricular pressure id greater than the outflow tract

Semilunar valves

When ventricles are relaxed and filling with blood (passively)

Diastole

Ventricular contraction, ejecting blood out of the heart actively

systole

Rapid ventricular filling

Reduced ventricular filling

Atrial contraction

Isovolumetric contraction

Inflow phase of cardiac cycle

Raid and reduced ejection

isovolumetric relaxation

Outflow phase of the cardiac cycle

Closing of the AV valves is the Lub (isovolumetric contraction)

S1

Closing of the aortic, pulmonary valves = dub ( semilunar valves closing)

S2

End diastolic volume-end systolic is the

stroke volume

Stroke volume times Heart rate is

Cardiac output

Normal cardiac output is **?L/Min**

5

End diastolic volume-end systolic volume/ end diastolic volume

ejection fraction

fraction of the end diastolic volume that is ejected during systole

ejection fraction

High function ejection fraction is greater than

70

Normal ejection fraction is

55-70

Low ejection fraction

40-55

Heart failure is less than what (ejection rate)

Lots of smooth muscle and elastin allowing it to stretch out when blood comes in and close back up to propel blood into the next major artery

structure of artery

Increasing the Sympathetic nervous system you?

Increase the radius of the arterioles

Decreasing the sympathetic nervous system you?

Decrease the radius of the arterioles

High metabolic areas, like muscles, liver, kidneys, nervous system

capillaries

Thins walls, low pressure, valves, strtcht, capable of radius change and reservoir for blood

Veins

Most of the blood is in

veins and venules

High pressure with arterial circulation- systemic system had resistance so higher pressure

Left Heart

Low for venous circulation- pulmonary system has low resistance so you don’t need a lot of pressure

Right heart

How does cross sectional area influence velocity

Inversely proportional

Stretchiness of a vessel is?

compliance

How is compliance calculated

Volume over Pressure

As volume increases **ANSWER** increases

compliance

As aortic pressure increases **ANSWER** decreases

compliance

High compliance means **ANSWER** venous return

less

Low compliance means **ANSWER** venous return

More

increased venous tone, venoconstriction, decreased venous compliance, venodilation, increased compliance, decreased tone =synonyms for a change in

radius

calculation for net filtration pressure

(Pc + pi(i)) -(Pc+ pi(c))

oncotic pressure in capillary

PI C

Oncotic pressure in the interstitium

PI I

Pull fluid into the capillary and out of the tissue

Oncotic pressure PI C

Pull fluid into the tissue and out of the capillary

Oncotic pressure PI I

Lubdub is turbulent flow caused by narrowed

arteries valves and disease

Systolic pressure - Diastolic pressure =

pulse pressure

\

2/3 DBP +1/3 SBP is what equation

Mean arterial pressure

Innervates via vagal nerve innervates SA and AV nodes

Parasympathetics

Innervates SA and AV node and ventricles

Sympathetics

IS a change in heart rate which affects the pacemaker potential of the SA node

Chronotropy

Alteration of intracellular CA levels in myocytes

Inotropy

Only affects Heart rate by decreasing slope of pacemaker potential via sa node. Does this by having ACH binding to M2 receptors which decrease funny NA and both T and L type ca channels

PNS effect on the heart

Increase heart rate by increasing slope of pacemaker potential in the SA node. Norepinephrine will bind to B1 adrenergic receptor to increase funny sodium channels and both T and L type Ca channels

SNS effect on the heart

An increase of MAP, stimulates the baroreceptor, which then takes the signal to the medulla and the medulla decreases heart rate and vasodilates to counteract MAP

baroreceptor reflex

The location of the Arterial baroreceptor reflex is in the

carotid sinus and aortic arch

Renin, which is made by the kidney cleaves to angiotensinogen making ANG-I, ACE is added to make ANG-II. ANG-II then binds to AT1R this……

Decreases blood volume, causing a drop in blood pressure, and decreased filtrate flow in their kidney

The air is made up of what percentage of N and O2

78% N and 21% O2

Barrier formation in the Lung

Type I alveolar epithelial cells

Surfactant in the lung

Type II alveolar epithelial cells

Immune cells in the lungs

Macrophages

As volume increases in the lung the resistance

Decreases

Because the chest protrudes outward and wants to extend. While the lungs want to collapse. These forces counteract and make

Pleural Space

Volume a the end of MAX inhalation. **Calculated by taking residual volume and vital capacity and adding them**

Total lung capacity