Download Heart Notes and Questions

Biology 12: The Heart Notes
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The Heart
Fist Sized
Myocardium
Pericardium
4 Chambers: 2 Atria
and 2 Ventricles
Auricles: ear-like flaps
of the atria
Septum: divides the
heart into 2
External Anatomy:
Coronary arteries (R
& L) surround heart;
embedded in SULCUS
and also some fat.
Biology 12: The Heart Notes
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INTERNAL ANATOMY:
VALVES: Atrioventricular Valves (AV) are between the atria and ventricles
The right side AV is TRICUSPID
The left side is BICUSPID = mitral valve
Both are supported by chordae tendineae (stop flaps from inverting)
Biology 12: The Heart Notes
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( note: these diagrams show the valves as seen from above)
Left
tricuspid
Bicuspid aka MITRAL
semilunar
Atrioventricular Valves
Right
semilunar
SEMILUNAR (3 half-moon shaped) valves control blood in arteries leaving the heart
PULMONARY semilunar valve
AORTIC semilunar valve
Biology 12: The Heart Notes
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Viewed from ABOVE ( superiorly)
Biology 12: The Heart Notes
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Biology 12: The Heart Notes
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What makes the “sounds” in a heart-beat?
Opening and closing of Valves at the start and end of SYSTOLE ( = contraction)
of the heart.
LUB =
DUB =
Biology 12: The Heart Notes
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HEART RATE CONTROL
1. The PACEMAKER of the heart, or SINOATRIAL node.
2. Hormones secreted by the adrenal glands into the bloodstream
3. Two sets of nerves that originate from the CNS ( mostly for slowing the heart)
1. The PACEMAKER of the heart, or SINOATRIAL node.
The heart CAN beat with NO direct stimulus from the nervous system due to the
SA node.
It can do this because it has a CONDUCTION SYSTEM : SA node, AV node, the
AV bundle and the Purkinje fibres.
1. The SA node
is located in the
dorsal wall of
the right
atrium. The
AV node is
located at the
base of the right
atrium.
2. The SA node, or
pacemaker, starts the cycle
Biology 12: The Heart Notes
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by sending a nerve impulse
through the heart, to BOTH
atria.
3.
When the SA signal reaches
the AV node, the AV node
sends a signal down thorough
the AV bundle. The AV
bundle reaches through the
septum, and then into small
fibres called Purkinje fibres
that relay the signal to heart
muscle cells.
The heart can beat on it’s own
if not stimulated by the SA
node, but it’s a bit slow.
The AV Bundle is also called
the Bundle of His.
2. Hormones secreted by the adrenal glands into the bloodstream
Biology 12: The Heart Notes
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Adrenaline = Epinephrine
Biology 12: The Heart Notes
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3. Two sets of nerves that originate from the CNS ( mostly for slowing the heart)
The heart is under AUTONOMIC control.
Nerves coming the cardioacceleratior center ( CAC) in the MEDULLA connect to the SA
node… these nerves release adrenaline (norepinephrine) that increase the heart rate.
To slow the heart rate, neurons from the MEDULLA ‘s cardioinhibitory center
(CIC) connect to the SA via the VAGUS nerve. These nerves release acetycholine
and SLOW the heart rate.
Nervous System Control
PARASYMPATHETIC
SYMPATHETIC
for resting
for action; fight or flight
decreases AV / SA node activity
increases AV / SA node activity
VAGUS nerve sends neurotransmitters to
SLOW the heart rate
norepinephrine/noradrenaline speeds heart
rate
Biology 12: The Heart Notes
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Questions: about the heart. Please answer on a separate sheet of paper. Short answers.
1.
On the diagram shown here, label the following structures:
superior vena cava
inferior vena cava
aortic arch
right atrium
left ventricle
right ventricle
aortic valve
tricuspid (AV) valve
pulmonary arteries
pulmonary veins
aorta
left atrium
pulmonary valve
mitral (AV) valve
septa
2.
Myocardium is composed of two root words. What does MYO mean? What does CARDIUM
refer to?
3.
What is the sac called that surrounds the heart?
4.
In the diagram of the heart at right, label the atria,
ventricles, apex, coronary arteries, aortic arch,
pulmonary arteries
5.
The cardiac cycle consists of three main events.
Describe them.
Biology 12: The Heart Notes
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6.
Atrioventricular valves are named so as they are situated_________________
7.
The bicuspid valve is on the _______ side of the heart, and is also known as the
___________________
8.
What is the role of the chordae tendineae ?
9.
Name the valves that control blood LEAVING the heart, and tell the position of each.
10.
Look at the pictures of heart valves in your handout. They are drawn from the perspective of
being ABOVE the heart. Why do the AV valves look so different from the Aortic and
pulmonary (semilunar) valves?
11.
In which chamber of the heart is the highest pressure generated?
12.
Why is the heart referred to as a “double-pump” ?
13.
Which ventricle has the thickest walls? Why?
14.
Describe the 3 major events that occur during the cardiac cycle.
15.
Explain the difference between systole and diastole.
16.
In the cardiac cycle, is there a time when the atria and ventricles are both in systole? is there a
time when the atria and ventricles are both in diastole?
17.
Where is the “pacemaker” of the heart?
18.
Which structure sends a signal to the AV node?
19.
The heart muscle is signaled to contract by way of the _______________ .
20.
In which units is blood pressure measured?
21.
What might be considered a “high” blood pressure?
22.
When blood pressure is measured, it is expressed in (some pressure) OVER (some other
pressure). Which number is diastolic pressure, the first or second?
Biology 12: The Heart Notes
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23.
In the diagram above, draw in the correct arterial blood pressures at the bottom of the graph.
24.
The heart is under control of the ___________________ nervous system.
25.
Generally speaking, the __________________ division of the autonomic nervous system tells
the heart to relax, slow down, and take it easy, while the ____________________ division
tells the heart to ____________________ . Also, adrenaline, produced by the
___________________ glands can tell the heart to ____________________ ; this is a
response termed the “__________ or _________ “ response.
26.
A human heart is about as big as a _____________
27.
During the cardiac cycle, the “lub” sounds is caused by..? The “dub” sound is caused by … ?
28.
Both the right and left sides of the heart
a. have semilunar valves between their chambers
b. consist of an atrium and a ventricle
c. pump blood to the lungs and the body
d. communicate with each other
e. all of these are correct
29.
Systole refers to the contraction of the
a. major arteries
b. SA node
c. Atria and ventricles
d. major veins
e. All of these are correct
Biology 12: The Heart Notes
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30.
During a heartbeat,
a. the SA node initiates an impulses that passes to the AV node
b. first the atria contract, and then the ventricles contract
c. the heart pumps blood out into the attached arteries
d. all the chambers rest for a while.
e. all of the above are correct
31.
The first heart sound, the “lub” of the “lub-dub” sound, is caused by
a. the closing of the semilunar valves
b. the closing of the atrioventricular valves
c. the contraction of the ventricles
d. the closing of all four valves at the same time
e. a heart murmur
32.
Blood leaving the right ventricle will move through pulmonary arteries, then to the lungs for
gas exchange. Which blood vessel was omitted from the sentence?
a. pulmonary trunk
b. pulmonary vein
c. aorta
d. superior vena cava
e. coronary arteries
33.
The heart is controlled extrinsically by two influences. What are they?
34.
After the ventricles have fully contracted, there is an immediate “dub” sound created by
vibrations in the heart tissue. Which valves are closing to create this sound?
35.
What is the function of the Bundle of His?
36.
The SA node is known as the pacemaker because it sets the pace of the heart rate. But the AV
node is also known as the gatekeeper of the pace of the ventricles. What would a properly
functioning AV node do if there were too many stimulations signaled by the SA node?
36.
The AV node also makes sure that there is a short delay between contraction of the atria and
the ventricles. What would happen if there were not enough of a delay?
37.
In WPW, or Wolff-Parkinson-White syndrome, there is an extra electrical pathway between
the atria and the ventricles that does NOT act as a proper gatekeeper of pace like the AV
node. What can happen to “Marilyn Manson” or “Meatloaf’s” heart function if they have
WPW?
Biology 12: The Heart Notes
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QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Biology 12: The Heart Notes
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