The Heart
SBI 3U
Ms. Raper
The Heart
• Is a pump
• Actually it is TWO pumps
• One pump deals with blood to the lungs, the
other pump deals with blood to the body.
• Heart is made of Cardiac Muscle
• The two sides are separated by a thick wall of
muscle called the SEPTUM
• The blood for the two pumps is kept separate in
mammals.
Fetal Heart circulation
• Because the fetus is not using its lungs,
the blood is “shunted” between the right
and left atria through a hole called the
foramen ovale. This usually closes shortly
before birth.
• Babies who do not have the foramen ovale
closed are born with a “hole in the heart”
This diagram shows
the path taken by the
blood through the
heart.
Use the following
link to label the
heart.
http://www.bishopstopford.com/f
aculties/science/arthur/Heart%2
0drag&drop.swf
http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/table22-3_blood_flow_th.jpg
Cardiac Muscle
The synchronous beating of the cardiac muscles are controlled by bundles
of nerves.
http://learninglab.co.uk/headstart/
Structure of the Heart.
• Four chambers, 2 upper called ATRIA
2 lower called VENTRICLES
• The Right side of the heart receives
deoxygenated blood from the body via the
superior and inferior vena cava.
• The Left side receives oxygenated blood
from the lungs via the Pulmonary veins
Valves of the Heart
• The atria and ventricles are separated by one way atrioventricular
valves.
• Between the right atria and right ventricle is the TRICUSPID valve
• Between the left atria and left ventricle is the MITRAL valve.
• SEMILUNAR valves are found at the base of the PULMONARY
artery and AORTA.
• The purpose of the valves is to prevent blood flowing backwards.
• Leaking of these valves can result in a heart murmur
Watch the heart valves at this link
•
http://www.wellesley.edu/Biology/Courses/111/HeartValves.MOV
Cardiac Cycle - Heart Beat.
• Phase 1 SYSTOLE – Contraction
“Occurs when the Ventricles contract, closing the AV
Valves and opening the SL Valves to pump blood into
two major vessels leaving the heart.”
• Phase 2 DIASTOLE – Relaxation
“Occurs when the Ventricles relax, allowing the back
pressure of the blood to closed SL Valves and opening
AV valves.”
(Mr. Johnson)
http://www.sirinet.net/~jgjohnso/circulation.html
http://www.biologymad.com/HeartExercise/HeartE3.gif
http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f22-11_cardiac_cycle_c.jpg
Check out the following link.
http://www.owensboro.kctcs.edu/gcaplan/anat2/notes/Notes5%20Cardiac%20Cycle.htm
EKG - electrocardiogram
•
•
•
•
•
•
•
Records the electrical activity of
the heart.
S-A node generates an electrical
impulse that spreads over the two
atria causing them to contract.
S-V node causes the ventricles to
contract.
P to Q represents the small
electrical voltage increase due to
depolarization when the atria
contract.
The large spike Q-S represents
the contraction of the ventricles.
As the ventricles recover, a small
spike at T precedes the next firing
of the S-A node
Check this link
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookcircSYS.html
Chemical Regulators of the Heart
• Noradrenaline: increase in CO2 stimulates
receptors in the blood vessels. The Medulla
oblongata sends impulses to produce
noradrenaline, this chemical causes the S-A
node to fire more rapidly
• Acetylcholine: increase in blood pressure
causes receptors in the blood vessels to send
the information to the medulla oblongata which
in turn causes the release of acetylcholine. This
chemical slows the firing of the S-A node.
Other chemicals that affect the
heart….
•
•
•
•
•
Nicotine – increases heart rate
Caffeine - increases heart rate
Amphetamine – increases heart rate
Cocaine – increased heart rate
Anabolic steroids – increased blood
pressure.
• Barbiturates – slow pulse
• Alcohol - decreases heart rate
• http://www.nida.nih.gov/DrugPages/DrugsofAbuse.html
Cardiac Output & Fitness
• Like all muscles, the heart needs exercise
• The volume of blood pumped out by the heart is
known as the CARDIAC OUTPUT.
• Factors that affect cardiac output are heart rate
and stroke volume
• Cardiac output = heart rate X stroke volume
Average person data
•
•
•
•
•
Stroke volume = 70mL
Heart rate = 70 beats/minute
Cardiac cycle = 70mL X 70beats/min
= 4900mL/min
There is a correlation between heart
health and fitness
Relationship between stroke volume, heart
rate & and cardiac output
Individual
Cardiac
output
Stroke
Volume
mL/beat
Heart Rate
Beats/min
A
4900
70
70
B
4900
50
98
C
4900
140
35
D
9800
70
140
•C is exceptionally fit has
a high stroke volume and
maintain a low hear rate.
•B is less fit
•Regular cardiovascular
exercise increases the
resting stroke volume.
•Fitness is measured by
how quickly the heart
rate returns to the resting
rate before exercise
began.
http://www.owensboro.kctcs.edu/gcaplan/anat2/notes/Notes5%20cardiac_equations.htm
Resources that you need to review
•
•
•
•
•
Text – Chapter 9
Mr. Johnson’s biology –chapter 46.
http://www.sirinet.net/~jgjohnso/circulation.html
Professor Fajer – Circulation, Heart & Blood
http://fajerpc.magnet.fsu.edu/Education/2010/20
10_INDEX.HTM
• Online Biology Book: Circulation
http://www.emc.maricopa.edu/faculty/farabee/BI
OBK/BioBookcircSYS.html
Check out these
• Biology animations:
http://science.nhmccd.edu/biol/index.html
• Anatomy & Physiology II
http://science.nhmccd.edu/biol/ap2.html
• Science animations:
http://science.nhmccd.edu/biol/animatio.htm
• And especially http://science.nhmccd.edu/biol/ap2int.htm
• Check out the section on cardiovascular.
• Anatomy of the Heart:
http://www.owensboro.kctcs.edu/gcaplan/anat2/notes/No
tes5%20Anatomy%20of%20the%20Heart.htm