Download Heart Sounds - Megan Semel

HEART SOUNDS
Biology 20 – Unit D: Human Systems
Pg. 324-326
Heart Sounds
♪Listen to your heart…
• Stethoscopes
Heart Sounds
• Lubb-dubb – caused by the closing of heart valves
• What are they called?
• Period of Relaxation/dilation = Diastole
• The heart fills with blood (atria and ventricles are relaxed)
• Period of Contraction = Systole
• The blood is pushed out of the heart
Lubb-Dubb
Lubb-Dubb Anatomy
Lets Take a Listen …
The Heart Sound Sequence
1. Diastole – chambers are relaxed (atria fill with blood)
2. Atria contract, fluid pressure increases in atria - AV
3.
4.
5.
6.
valves open
Blood flows from the atria into the ventricles
Systole – Ventricles contract when full
Pressure forces AV valves shut (lubb), blood pushes
blood through SV valves and into the arteries
Ventricles relax; As their volume increases, pressure
decreases  blood wants to move to an area of lower
pressure, however, the SV valves are one way and shut
(dubb)
Heart Murmurs
• When valves do not
close completely
• Improper seal
• Occurs mostly in AV
valves (especially the
Bicuspid valve)
• Gurgling sound
• Decreased Oxygen
• Heart Compensates by
beating faster
• Heart enlarges
The Heart Fights Back!
• The more cardiac muscle is
stretched, the stronger it
contracts
• When blood abnormally
flows from the ventricle back
into the atrium, volume in the
atrium increases
• There is now blood from both
the ventricle and normal
blood from the vein
• The extra volume stretches
the atrium and creates more
forceful contraction
ECG (Electrocardiogram)
• Maps electrical activity in the heart
• To diagnose heart problems
• Reveals normal or abnormal heart rhythms/beats
• Displayed on a graph called an ECG (electrocardiogram)
ECGs
• P wave – first wave
• Electrical impulse that
causes atrial contraction
• QRS wave – larger
spike
• Electrical impulse that
causes ventricular
contraction
• T wave – final wave
• Ventricles have
recovered
ECGs
ECGs
• By comparing electrical outputs to normal results
(control), physicians are able to locate the area of the
heart that is damaged
• Useful for monitoring the body’s response to exercise
• Some heart conditions are revealed during exercise
Irregular Heartbeat
• Arrhythmia
• Caused by a blocked coronary artery
• Heart beats in an irregular pattern
• Less blood  less O2
• Toxic products accumulate and can initiate contractions
• Wild contractions/ not coordinated (ventricular fibrillation)
• Faster heart beat
Medications
• Foxglove (traditional
homeopathic)
• Digitalis – active
ingredient
• Initiates strong, regular
heart contractions
• Treats congestive heart
failure
• Nitroglycerine
• Relaxes smooth muscles
and dilates blood
vessels
Medications
• Beta-blockers
• Help people with
irregular heart beats or
high blood pressure
• Eg. Beta-blockers
inhibit epinephrine
• Side effects:
• Slows the heart
• Tired,
lightheadedness/dizzine
ss (low blood pressure)
Chicken Embryo Heart Beat
Chicken Embryo Heart Beat
What do you think would happen to the
heart rate if you added a drop of caffeine
(Coke/Red Bull) into the egg?
Measure Up!
• Measure the electrical
output of your heart
using the ECG
machine (ECG in
British English; EKG in
American English)
• Fill out the provided
handout
Summary
• Diastole is heart
• Systole is heart
• Lubb-dubb sound is caused by
• A murmur is when
• An ECG maps