15 cardiovascular
DESCRIPTION
Heart, blood vessels, flow of blood through the heartTRANSCRIPT
Chapter 15Cardiovascular System
Cardiovascular System
• heart• blood vessels
Average Size of Heart• 14 cm long• 9 cm wide•Fist-sized
Know all of this!
Heart Chambers
Right Atrium• receives blood from
• inferior vena cava• superior vena cava• coronary sinus
Left Atrium• receives blood from pulmonary veins
Right Ventricle• receives blood from right atrium
Left Ventricle• receives blood from left atrium
Heart Valves
Tricuspid Valve• right A-V valve• between right atrium and right ventricle
Bicuspid Valve• left A-V valve• aka mitral valve• between left atrium and left ventricle
Pulmonary Valve• semilunar valve• between right ventricle and pulmonary trunk
Aortic Valve• semilunar valve• between left ventricle and aorta
Path of Blood Through the Heart
Blood and its flow
• Remember that deoxygenated blood is represented by blue (but it is actually a deep, deep red)
• Oxygenated blood is represented by red and would be bright red in real life
• The deoxygenated blood always comes back to the heart and enters the right side (but from our view it looks like the left)
• It leaves and goes to the lungs to get oxygenated• It then enters the left side of the heart before getting
pumped out the aorta to the rest of the body
Path of BloodThrough the Heart
Pulmonary Circuit (lungs)CO2 blood from the
body
CO2 blood from the body
CO2 to the lungs
Superior vena cava
O2
CO2
Systemic Circuit (body)
O2 blood from the lungs
O2 blood from the lungs
O2 blood to the body
CO2
O2
Summary
•Atria receive blood
•Ventricles pump blood out of the heart
•Arteries carry oxygenated blood away from the heart
•Exception: pulmonary arteries carry deoxy. from the heart to the lungs
•Veins carry deoxygenated blood back to the heart
•Exception: pulmonary veins carry oxygenated blood from the lungs to the heart
Review of blood flow
• Deoxygenated blood comes in the SVC or IVC to the Rt. Atrium
• Through the tricuspid valve
• To the Rt. Ventricle
• Out the pulmonary valve
• Into the pulmonary artery
• To the lungs to get oxygenated
• Oxygenated blood comes back to the heart in the pulmonary veins into the Lt. Atrium
• Through the bicuspid valve
• To the Lt. Ventricle
• Out the aortic valve
• Into the Aorta and out to the rest of the body
The explanation of blood flow on the worksheet is great except that it leaves out the valves that are getting passed through, make sure you know that too!
“Pumps your Blood”
Coronary Arteries
• These are the arteries that feed the heart muscle with oxygen
• If these get clogged you have a heart attack• When oxygenated blood gets pushed into the aorta
there are detours leading to the coronary arteries• Coronary arteries right and left cardiac veins
coronary sinus right atrium
Summary of Changes During Cardiac Cycle
Lubb dupp
• This is the terminology most scientists use to describe the sound of the heart
• It is made by the opening and closing of valves• The lubb sound is made by the A-V valves closing• The dupp sound is made by the aortic and
pulmonary valves (semilunar) closing• Listen to your partners (or your) heart for this
sound with the stethoscope
The conduction of the heart
• Remember how your heart can even beat outside of your body???
• It has its own electrical system!!
The conduction of the heart
• The Sinoatrial (SA) node is at the top of the rt. atrium
• The Atrioventricular (AV) node is at the bottom of the rt. atrium (in between atrium and ventricle)
• The impulse is conducted down the septum of the ventricles
• It then branches back up
S-A node
A-V node
Follow the path!
Electrocardiogram
• recording of electrical changes that occur in the myocardium• used to assess heart’s ability to conduct impulses
P wave – atrial depolarization; about to contractQRS wave – ventricular depolarization; about to contractT wave – ventricular repolarization
Regulation of Cardiac Cycle
• physical exercise• body temperature• concentration of various ions
• potassium• calcium
• parasympathetic impulses decrease heart action• sympathetic impulses increase heart action• cardiac center regulates autonomic impulses to the heart
Regulation of Cardiac Cycle
Autonomic nerve impulses alter the activities of the S-A and A-V nodes
Blood Vessels
• arteries• carry blood away from ventricles of heart
• arterioles• receive blood from arteries• carry blood to capillaries
• capillaries• sites of exchange of substances between blood and body cells
• venules• receive blood from capillaries
• veins• carry blood toward RA of heart
*Veins have valves because they have to work against gravity. With each pump of the heart the blood goes through a valve and can’t go back!
Capillary Network
Regulation of Capillary Blood Flow
Precapillary sphincters • may close a capillary• respond to needs of the cells• low oxygen and nutrients cause sphincter to relax
Arterial Blood Pressure
Blood Pressure – force the blood exerts against the inner walls of the blood vessels
Arterial Blood Pressure• rises when ventricles contract• falls when ventricles relax• systolic pressure – maximum pressure• diastolic pressure – minimum pressure
Blood Pressure
• Desired to be under 120/80• Measured in mmHg• Top number is systolic (pressure when heart contracts)• Bottom number is diastolic (pressure when heart is at rest)• Both are important but especially the bottom number
because your heart needs to rest• Learn and practice taking blood pressure with a
sphygmomanometer