Pulmonary Circulation Conus arteriosus

Superior end of the right ventricle Leads to the Pulmonary Trunk

Pulmonary Trunk Divides into Left and Right Pulmonary

Arteries Blood flow:

Right Ventricle -> Pulmonary Trunk through the Pulmonary Semilunar Valve (PSL Valve)

Pulmonary valve has 3 Semilunar cusps

Systemic Circulation

Blood leaves Left Ventricle through …• Aortic Semilunar Valve (ASL

Valve) into Ascending Aorta

Ascending Aorta turns to the left into the … Aortic arch and becomes the …. Descending Aorta

Systemic Circulation Structural Differences between the Left & the

Right Ventricle:

1. Left Ventricle Round Thicker myocardium wall -> more pressure

2. Right Ventricle Pouch shaped Thinner myocardium wall -> less pressure

Coronary Sinus Cardiac veins return blood to coronary

sinus Cardiac sinus opens into Right Atrium

Writing Activity (10 points) You are a Erythrocyte (RBC) traveling through the human

body. Describe the journey! Condition in lungs for O2 pick up Heart: atria, ventricles, 4 valves Systemic pathway Pulmonary pathway Conditions of tissue for O2 dispersal & CO2 pick up

2 Bonus points: if all possible names for valves are given Example: Atrioventricular valve, Mitral valve, …

Foramen Ovale Before Birth; an opening through

the Interatrial Septum Connects the two Atria Eliminates blood being sent to the

lungs in a Fetus!!

Seals off at birth -> Fossa Ovalis

Blue Baby Foramen ovale does not deal off

after birth Requires surgery

Heart Valves

Left AV valve:Bicuspid valveMitral valve

Aortic Semilunar Valve

Right AV Valve:Tricuspid

Pulmonary Semilunar Valve

Tricuspid Valve Bicuspid ValveMitral Valve

Aortic Semilunar Valve

Pulmonary Semilunar Valve

Cardiac Conduction Heart Beat

• A single contraction of the heart

The entire heart contracts in sequence1. Atria2. Ventricles

Cardiac Conduction Structures of the Conducting

System Sinoatrial (SA) nodes

In the wall of the Right Atrium

Atrioventricular (AV) node Between Atrium & Ventricle

Conducting Cells Throughout myocardium

The Cardiac Cycle Begins at the Sinoatrial ( SA)

Node with an Action Potential

The Action Potential is transmitted through the conducting System:

1. SA node2. AV node

Produces an Action Potential in the Cardiac muscle cells

• Contractile cells

5 Steps to the Cardiac Cycle:

1.Ventricular diastole 2.Atrial systole begins3.Atrial diastole4.Ventricular systole 1st phase5.Ventricular systole 2nd

phase

Diastole = RelaxationSystole = Contraction

5 Steps to the Cardiac Cycle:

1.Ventricular diastole All chambers are relaxed

Diastole = RelaxationSystole = Contraction

5 Steps to the Cardiac Cycle:

2. Atrial systole begins Atria contract & force

blood into ventricles

Diastole = RelaxationSystole = Contraction

5 Steps to the Cardiac Cycle:

3. Atrial diastole Atrium contraction ends Atrium relaxes Ventricle contractions begin

Diastole = RelaxationSystole = Contraction

5 Steps to the Cardiac Cycle:

4. Ventricular systole 1st phase

Contraction pushes AV valves close

Diastole = RelaxationSystole = Contraction

5 Steps to the Cardiac Cycle:

5. Ventricular systole 2nd phase

Increase in pressure forces SL valves to open

Blood is ejected

Diastole = RelaxationSystole = Contraction

5 Steps to the Cardiac Cycle:

1.Ventricular diastole 2.Atrial systole begins3.Atrial diastole4.Ventricular systole 1st phase5.Ventricular systole 2nd

phase

Diastole = RelaxationSystole = Contraction

Sinoatrial (SA) Node

Pacemaker of the heart Initiates heart beak Sends excitatory impulses every 0.85

seconds

Contracts: Atrium

Impulse is send to AV node

Atrioventricular (AV) Node Sends impulses to AV bundles Bundles branch into Purkinje

fibers Cause ventricle to contract

Cardiac Cycle

Cardiac Cycle - Review Is the period between the start of one heartbeat and the

beginning of the next

Includes contraction & relaxation with the Atria & Ventricle Systole

Contraction Diastole

relaxation

Phases of the Cardiac CycleAtrial systole

Ventricular systole phase 1

Atrial diastole

Ventricular systole

phase 2

Ventricular diastole

Cardio dynamics

Cardiac center is in the Medulla Oblongata

Cardio acceleration is controlled by the sympathetic neurons

Cardio inhibition is controlled by the parasympathetic neurons

Vagus Nerve (Cranial Nerve X) carries fibers to the heart