Heart & Blood Vessel Guided Notes
Name:__________________________
Do Now
Write down 1-3 questions about how your heart works.
Cardiovascular System
What is the major function of the cardiovascular system?
What is the heart’s role in this system, and what are the other major components?
Heart Size and Location
Describe the heart size,
location, and tilt.
Heart Layers. Describe the location and function of the three layers.
Pericardium –
What is pericarditis?
Myocardium –
Endocardium –
Cardiac circulation
Cardiac vessels cover the outer surface of the heart and supply the heart muscle itself with blood.
Heart disease (___________________________) occurs when the aorta or cardiac arteries
Heart Anatomy (Frontal Section)
The heart is a double pump
•
The ____________________ of the heart receives
________________________________________
________________________________________ and
pumps it to the _____________________
 ________________________________________
•
The ______________________ of the heart receives
_________________________________________
_________________________________________ and
pumps it to the _____________________
 ______________________________________
The heart has four chambers

Each side has an ___________________________________________________ and a _____________
____________________________________________________________

Blood collects in atria while ventricles contract.

Then, as ventricles relax, atria contract slightly and ventricles refill.

Two sides of heart contract and relax simultaneously.
Flow of Blood
Use the diagram to determine the flow of blood
through the heart and body.
Vena cava









Vena cava
The walls of the ventricles are much thicker than that of the atria? Why?
Look at the diagram – how does the left ventricle differ from the right? What is the reason for the difference?
Heart valves ensure unidirectional flow of blood
valves (tricuspid and mitral)
•
hang open when the ventricles are filling
•
forced closed when the ventricles contract
•
Anchored by ___________________________
Prevent backflow from ____________________
to ______________________________
_________________________________ (pulmonary and aortic)
• forced open when ventricles contract
• closed when ventricles relax
Prevent backflow from ______________________ to _____________________
In what stage of the cardiac cycle is the heart shown above? How do you know?
Heart Sounds
Normal hearts make the sound:
LUB-dup LUB-dup LUB-dup
The “LUB” is caused by the closing of the _________________________________.
The “dup” is caused by the closing of the _________________________________.
Heart murmurs are __________________________heart sounds.
• In children, these are often benign.
• In adults, they usually indicate a problem – often, the _____________________________________
_______________________________________.
Why is it a problem if the valves don’t function properly?
ECG and the Heart’s Internal Conduction System Guided Notes
Do Now
What is an action potential and where do they occur?
Intrinsic conduction system

_______________ is the heart’s natural pacemaker.
◦

Impulse travels throughout the ____________ and to
the ________________
◦
_______________________________________
_______________________________to allow atria to
finish contracting

The ______________ (aka bundle of His) transmits
the impulse to the _______________________ and
______________________________________.
Interestingly, all the cells of the conduction system are
_______________________________.
That is, all will depolarize at a certain rate.
The __________________ has the fastest rate of
depolarization, though, so it sets the pace for the entire heart.
What is the function of
-
AV node
-
Gap junctions
Travels cell-to-cell through __________
_________________ in intercalated discs –
another unique feature of cardiac muscle

◦
Quick Review – Intrinsic Conduction System
It depolarizes ~75 times / min, to start each
heartbeat.
◦
These bundles and fibers speed the
transmission of the impulse throughout the
ventricles, to coordinate ventricular
contraction
-
SA node
-
Purkinje fibers
Name 3 differences between cardiac and skeletal muscle contraction & explain why each is important to cardiac
function.
ECG

An electrocardiogram (ECG or EKG) records the electrical current
through the heart.

A normal ECG has three distinct waves:
◦
P wave – atrial depolarization
◦
QRS complex – ventricular depolarization AND atrial
repolarization
◦
T wave – ventricular repolarization
ECG Questions
What is responsible for the delay between P wave and QRS complex?
What is responsible for the delay between T wave and next P wave?
Examine this normal ECG.
 When would the ventricles be in systole?
 When would they be in diastole?
 When would the heart sounds occur, and what do the heart sounds correspond to?
ECG abnormalities
Examine these ECG readouts, and identify how they differ from a normal ECG.
a)
b)
c)
d)
Descriptors –
Name
AV block
Atrial fibrillation
Tachycardia
Bradycardia
Characteristic ECG
In severe cases, there is NO
relationship between P waves and
QRS complex. QRS still occurs
due autorhythmic cells in AV
node, but at a slower rate.
Wavy baseline, no regular p waves
QRS normal shape but occurs
randomly
Looks messy
Heart beats faster than normal
(more than 100 bpm)
Heart beats slower than normal
(less than 60 bpm)
Cause(s)
Damage to AV node, such as from
reduced blood flow (ischemia) or
fibrosis.
Treatment: dual chamber artificial
pacemaker- one that ‘listens’ to the
SA node and sends a signal to the
AV node
Heart is doing uncoordinated,
ineffective contraction due to lack
of blood, excess alcohol, or
infection
Exercise, drugs
Many conditions, including heart
damage, medications, etc,
Regulation of Heart Rate
Earlier, we said that the SA node depolarizes at a rate of ~75 beats per minute, and that this acts as a pace maker
for heart contraction.
Does this mean our hearts always beat at ~75 bpm?
What are the two branches of the autonomic nervous system, and how do they affect heart rate?
Other factors that influence heart rate
 Age (fastest in fetus, young children)
 Gender (faster in females)
 Temperature (faster in heat)
 Exercise (faster with exercise)
 Ions imbalances & medicines (faster or slower)
 Weak / damaged heart (can be either faster / slower)
Blood Vessels
Types of Blood Vessels
Draw a cycle that shows how blood
flows through the heart and blood
vessels.
Blood Vessel Tunics
 All vessels except capillaries have three layers, or tunics
 Capillaries have a single layer of epithelial cells
Different vessels differ in the thickness
and adaptations of each tunic.
Comparison of the blood vessels
Explain the function of each special feature
Blood vessel micrograph
Which is which? How can you tell?
How does blood return to the heart?
Muscular pump
Respiratory Pump
How does the muscular pump work?
How does the respiratory pump work?
Capillary Bed
What is the difference between the vascular
shunt and a true capillary?
What is the function of the precapillary
sphincters?