Download autonomic nervous system

Do Now 11/5/14
1. Which chambers of the heart act as pumps?
2. Where does blood go after it leaves the right ventricle?
Through what valve does it pass?
3. What are the substages of systole? Describe the
relaxation/contraction of the chambers and the
opening/closing of valves at each substage.
4. What are the substages of diastole? Describe the
relaxation/contraction of the chambers and the
opening/closing of valves at each substage.
Regulation of the
Heart
agenda
Do Now
Quiz
Regulation of the heart
Practice
RAFT
ECG
Exit Ticket
5 min
20 min
15 min
10 min
10 min
15 min
5 min
Objectives
By the end of today’s class period, I will be able to …
Describe the control centers of the heart
Describe how the heart receives electrical impulses
Describe what an ECG is and how it is interpreted
Regulation of the heart
There are three regulation mechanisms of the heart
1 internal – sinoatrial node
2 external – medulla oblongata, endocrine system
Internal control
The sinoatrial node (pacemaker) produces an electrical impulse
which tells the heart to beat.
It is located in the right atrium.
Two forms of external control
Medulla Oblongata: located in the brain
Endocrine system
The cardiac center
The cardiac center is located in the medulla oblongata
Controls the autonomic nervous system
The autonomic nervous system
Baroreceptors located in the atria, aortic arch and carotid
arteries monitor blood pressure and send info to the cardiac
center
Autonomic nervous system:
Sympathetic branches increase heart rate
Parasympathetic branches decrease the heart rate
The endocrine system
Glands in the endocrine system secrete hormones
Epinephrine (adrenaline), norepinephrine, and thyroxine
increase the heart rate
The Conduction system
The conduction system transmits signals which control heart
rate and contraction strength
The pathway of an electrical
impulse
1. The sinoatrial node creates the impulse
2. The impulse goes to the left atrium and the atrioventricular
node (between the right atrium and right ventricle) – atria
contract
3. The impulse travels down the atrioventricular bundles in
the interventricular septum (middle of the heart) to millions
of Purkinje fibers
4. The Purkinje fibers stimulate the ventricles to contract.
The pathway of an electrical
impulse
1. The sinoatrial node creates the impulse
2. The impulse goes to the left atrium and the atrioventricular
node (between the right atrium and right ventricle) – atria
contract
3. The impulse travels down the atrioventricular bundles in
the interventricular septum (middle of the heart) to millions
of Purkinje fibers
4. The Purkinje fibers stimulate the ventricles to contract.
View the heart
animations at
McGraw Hill to
understand the
Cardiac Cycle
Practice
Discuss all of the following questions with your partner, but do
not shout out.
I will call on one person to answer each question
Question #1
What are the 3 different mechanisms that regulate the heart?
#1. Sinoatrial Node
#2. Cardiac center in the medulla
oblongata
#3.Endocrine System
Question #2
What is another term for the sinoatrial node? What does it do?
Pacemaker. It creates electrical
impulses to tell the heart to pump.
Questions #3
The cardiac center has two branches of fibers that send
messages to the brain. What is this nervous system called?
What are the branches called?
Autonomic Nervous System
Sympathetic and Parasympathetic
Branches
Question #4
Describe the difference between the roles of the sympathetic
and parasympathetic branches.
Sympathetic increases HR
Parasympathetic decreases HR
Question #5
List the order in which an electrical impulse travels through the
heart.
#1 originates in the sinoatrial node
#2 Travels to the Left Atrium and the
Atrioventricular Node
#3 Travels from the AV node down the
center of the heart.
#4 The signal splits to go to each
ventricle through the Purkinje fibers
RAFT (role audience format topic)
The body contains many pathways for electrical impulses, of which the heart
is just one pathway.
Write a journal entry as if you are a nerve impulse the usually works in the
muscular system but are sightseeing in the heart’s control center.
Role – nerve impulse
Audience – fellow nerve impulses working the muscular system
Format – journal entry
Topic – you usually work in the muscular system but you are sightseeing in
the heart’s control center. Begin at the cardiac center and end at the
Purkinje fibers.
Electrocardiogram (ECG)
Interpretation of the electrical activity of the heart over a
period of time as detected by electrodes attached to the
surface of the skin
ECG – electrocardiogram – a recording of the
electrical events (changes) during a cardiac cycle
•P Wave – depolarization of
the atria (atrial contraction
– systole)
•QRS Complex –
depolarization of the
ventricles (ventricular
contraction, systole)
•T Wave – Repolarization of
the ventricles
Heart Sounds – opening and
closing of the valves, flow of
blood into and out of the
chambers, vibrations in muscle
Interpreting ECGs
An ECG is printed on paper covered with a grid of squares.
Notice that five small squares on the paper form a larger square.
The width of a single small square on ECG paper represents 0.04
seconds.
A common length of an ECG printout is 6 seconds; this is known
as a "six second strip."
Types of Arrhythmia
Arrhythmia – abnormal heart rhythm causing
the heart to be unable to pump blood
effectively
Bradycardia – heart rate below normal range, resting
heart rate under 60 BPM
Tachycardia – heart rate exceeding normal range,
resting heart rate over 100 BPM
Analyze an ECG
Each one of the figures
represents an ECG pattern
displaying three types of
abnormal rhythms: Tachycardia,
Bradycardia, and Arrhythmia.
Identify each.
Exit Ticket