Heartoxy artery arterioles capillaries (half blue)gas exchange venuolesdeoxy veins heart Systemic circulation:

heart oxy

artery

arterioles

capillaries (half blue)gas exchange

venuolesdeoxy

veins

heart

Systemic circulation:

THREE CIRCULATORY SYSTEMS

- overall there are 3 circulatory systems in your body

1) Systemic- delivers blood between the heart and body cells

2) Pulmonary- blood goes to the lungs to be oxygenated- delivers blood between the heart and the lungs

3) Cardiac- circulation of blood in the heart

The Heart

CARDIAC CIRCULATION

• the mammalian heart is a double pump, separated by a wall of muscles called a septum

• each side of the heart is divided into two chambers: an upper atrium and a lower ventricle (four chambers in total)

• it is used to push blood through the body and provides a connection between our pulmonary and systemic circulatory systems

• it is supplied by blood via the coronary arteries (come off main aorta)

• http://www.fed.cuhk.edu.hk/~johnson/teaching/transport/animations/HyperHeart.swf

Heart Sounds: lubb-dubb• caused by the closing of the heart valves

1) Diastole- relaxation of the ventricles, atria fill with blood

2) Systole- contraction of the ventricles, atrioventricular valves close (lubb) and blood is pushed through the semilunar valves, as semilunar valves close you get the dubb

• (if valves don’t close properly, esp. the bicuspid (left), you get a murmur (soft gurgling as blood comes back to the atrium from the ventricle

SETTING THE HEART’S TEMPO• the heart’s tempo or beat rate is set by the sinoatrial

(SA) node

– located where the venae cavae enter the right atrium

– acts as a pacemaker, setting a rhythm to ~70 beats per minute

– from the SA node the contractions travel to the atrioventricular (AV) node, which sends the contractions through to the walls of the heart, causing the atria to contract first, and then the ventricles (using Purkinje fibers)

• seen on an ECG, p.260, dead tissue doesn’t conduct electrical signals well to you can see where the problem is

Purkinje fibers

- carry the signal from the AV node to the bottom tip of the heart, allowing the ventricles to contract simultaneously

•seen on an ECG, dead tissue doesn’t conduct electrical signals well to you can see where the problem is

OVERALL CARDIAC CIRCULATION- deoxygenated blood is collected

from your upper body through the superior vena cava

from your lower body through the inferior vena cava

right atrium

(through atrioventricular tricuspid valve)

right ventricle

(through semilunar valve)

right pulmonary artery left pulmonary artery

right lung left lung

capillaries -> CO2 exchanged for O2 through simple diffusion

pulmonary veins

left atrium

(through atrioventricular bicuspid valve)

left ventricle

(through semilunar valve)

aorta

arteries

arterioles

veins

venules

capillaries (O2 is dropped off, CO2 is picked up)

• Homework:– P.263 #1,2,3, 5, 6,7