The Heart

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  • Created by: Lotto65
  • Created on: 24-03-17 16:25
What is the name of the muscle that makes the walls of the heart contract?
Cardiac muscle
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What is the special property of cardiac muscle?
Can contract on its own without being stimulated by a nerve
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What is the official name of the cardiac muscle's special property?
Myogenic contraction
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What are the names of the arteries that supply blood to the heart muscle?
Coronary arteries
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Coronary arteries branch off from the...
Aorta
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By which valve does the aorta branch into coronary arteries?
Semi-lunar valve
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What does blood bring to the cardiac muscle?
Nutrients and oxygen
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The oxygen is for aerobic respiration but what does the energy produced do?
It is used for cardiac muscle contraction
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The atria are ... chambers
Collecting
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The ventricles are ... chambers
Pumping
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What acts as a pacemaker in the heart?
A group of specialised cardiac muscles cells
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How do the specialised cardiac cells act as a pacemaker?
They initiate each contraction
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Where are the specialised cardiac cells located?
Right atrium
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What are the specialised cardiac cells called?
Sinoatrial node
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How does the sinoatrial node initiate contraction?
Sends out an electrical signal
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Where does the electrical signal reach first and then second?
The walls of the atrium and then the walls of the ventricles
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How can messages be sent to the sinoatrial node?
Nerves or hormones
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Where in the brain do impulses come from to go to the SA about changing heart rate?
Medulla
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How many nerves do impulses travel down to get to the SA from the brain?
2
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What do the two nerves do to heart rate?
One slows down the rate and one speeds it up
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Which hormone increases heart rate?
Epinephrine
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What does epinephrine help prepare the body for?
Vigorous physical activity
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What causes CHD?
Fatty plaque builds up in the inner lining of the coronary arteries
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What does 'occluded' mean?
Narrowed
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What happens if coronary arteries become occluded?
It restricts blood to the heart muscle, causing chest pain
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What makes the fatty plaque hard and tough?
Minerals that get deposited in plaque
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What are some causes of CHD?
Smoking, high blood cholesterol levels, high blood pressure, high blood sugar levels, genetic factors
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What is another word for high blood pressure?
Hypertension
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What usually causes high blood sugar levels?
Diabetes
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What do we mean by 'genetic factor'?
Family have history of the disease
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What does CHD stand for?
Coronary heart (or artery) disease
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What does 'dorsal' mean?
The back
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What does 'ventral' mean?
The front
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How many flaps does a semi-lunar valve have?
3
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What does the septum contain?
Conducting fibres to stimulate the ventricles to contract
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How is heart muscle myogenic?
The membrane of heart muscle cells depolarises when the cell contracts which activates adjacent cells
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Which cells in the heart are the first to depolarise?
The cells in the sinoatrial node
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What are the properties of the cells in the sinoatrial node?
Extensive membranes and a few proteins that cause contraction in other muscle cells
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What is used to replace a defective pacemaker?
An artificial pacemaker or output regulation
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What is an artificial pacemaker?
An electronic device that is placed under the skin with electrodes implanted in the wall of the heart that initiate the heartbeat
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How can electric signals spread through the walls of the atria?
There are interconnections between adjacent fibres and the fibres branch out
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What is the time delay before the electric signal is conveyed to the ventricles?
0.1 seconds
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Why is there a time delay between atria and ventricle contraction?
Allows time for atria to pump blood into the ventricles
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How does the cardiovascular centre receive information on the blood?
Receptors that monitor blood pressure, oxygen concentration and pH
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What does the pH of the blood show?
It's carbon dioxide concentration
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Low blood pressure, oxygen concentration and pH suggests...
The heart rate needs to speed up
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High blood pressure, oxygen concentration and pH suggests...
Heart rate needs to slow down
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What is another name for epinephrine?
Adrenaline
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Where is epinephrine produced?
Adrenal glands
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What controls the secretion of epinephrine?
Brain
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When does epinephrine secretion increase?Why?
During vigorous exercise to prepare for fight or flight
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How do athletes ensure their heart rate is already increased when vigorous activity begins?
Pre-race routines to stimulate adrenaline secretion
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What is atherosclerosis?
The development of fatty tissue in the artery wall adjacent to the endothelium
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What is the name of this fatty tissue build up?
Atheroma
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How do atheromas develop?
Low density lipoproteins (LDL) accumulate and phagocytes are attracted by signals from smooth muscle and endothelium. Smooth muscle cells migrate to form tough cap over atheroma so bulges into lumen, restricting blood flow
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What do the phagocytes do in atherosclerosis?
Engulf the fats and cholesterol by endocytosis and grow very large
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What do low density lipoproteins contain?
Fats and cholesterol
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Do atheroma in children's arteries affect health?
No
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How can atheroma in older people affect health?
Goes unnoticed until major artery becomes so blocked the tissues it supplies are compromised
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What is coronary occlusion?
Narrowing of the coronary arteries
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What is anoxia?
Lack of oxygen
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What are the symptoms of atherosclerosis?
Angina, increased heart rate, impairs muscle's ability to contract, anoxia, acute heart problems
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How can atherosclerosis cause acute heart problems?
The fibrous cap covering atheromas sometimes ruptures to stimulate blood clots to form which blocks arteries supplying blood to the heart
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Why does heart rate increase with atherosclerosis?
Lack of oxygen causes impairment of heart muscle so heart beats faster to try and maintain circulation while some muscle is out of action
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What are some theories regarding the causes of atherosclerosis?
High LDL concentrations, high blood glucose concentrations, high blood pressure, consumption of trans fats, infection of artery wall with chlamydia pneumoniae and production of trimethylamine N oxide by microbes in intestine
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What are some causes of high blood glucose concentrations?
Overeating, obesity, diabetes
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What causes high blood pressure?
Smoking, stress
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How does consuming trans fats affect the artery?
Damages endothelium lining
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What is systole?
Contracting
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What is diastole?
Relaxing
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What creates the heartbeat sound?
The valve flaps shutting
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Atrium contracting --> ventricle contracting --> ...
All relaxing
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If the heartbeat makes a 'lubdub' sound, which sound is louder?
Dub
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What is the name of the atrioventricular valve on the right side?
Tricuspid valve
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What is the name of the atrioventricular valve on the left side?
Bicuspid valve
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What is the name of the cardiac muscle?
Myocardium
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What is the purpose of the non-conducting septum between the atria and ventricles?
Prevents cardiac impulse in atrial muscles spreading directly into ventricles
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What is the name of the node in also in the wall of the right atrium?
Atrio-ventricular node
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What is the name of the conductive bundle that the AV transmits impulses down?
His
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After reaching the apex of the heart, which fibres do the impulses spread up?
Purkinje fibres
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What are the two types of semi-lunar valves?
Pulmonary and aortic
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What makes valves respond?
Blood pressure changes by contraction and relaxation of heart chambers
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What prevents the atrioventricular valves inverting?
Chordae tendineae
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Which muscle alllows the chordae to stretch?
Papillary muscle
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What prevents the semi-lunar valves inverting?
Thickened ridges on the valve's leaflets
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Are the semi-lunar valves tricuspid or bicuspid?
Tricuspid
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As blood flows in to the ventricles, what happens to the venae cavae and pulmonary vein?
Sphincters close
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What is the name of the valve between the left atrium and left ventricle?
Mitral valve
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What is stroke volume?
The amount of blood pumped out of the left ventricle of the heart during a contraction
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What is cardiac output?
The amount of blood the heart pumps around the circulatory system in one minute
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What is a more elaborative name for the septum in the heart?
Interventricular septum
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What is isovolumetric contraction?
When the ventricles contract but this results in no volume change (occurs at the start of systole)
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What is the name of the nerve that causes the heart to beat faster?
Cardiac accelerator nerve
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What is the name of the nerve that causes the heart to slow down?
Vagus nerve
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Where do the nerves come from that control the heart rate?
Medulla oblongata
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Where do the nerves controlling heart rate attach to?
Sinoatrial node
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How does epinephrine help with the heart rate?
Increases the conduction speed of electrical impulses from the sinoatrial node and atrioventricular node. Also increases rate electrical impulses are sent from sinoatrial node
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What else does epinephrine do?
Increases muscle strength, sugar metabolism and blood pressure
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Why do we need fats in our diet?
Insulation, energy and a starting material for certain hormones and anti-inflammatory compounds
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What is angina?
Chest pain due to heart cells not being supplied with enough oxygen and glucose
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What can cause high blood pressure?
Smoking and stress
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What does diabetes cause?
High blood glucose concentration
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What sort of diet could cause atherosclerosis?
A diet high in trans fats
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Other cards in this set

Card 2

Front

What is the special property of cardiac muscle?

Back

Can contract on its own without being stimulated by a nerve

Card 3

Front

What is the official name of the cardiac muscle's special property?

Back

Preview of the front of card 3

Card 4

Front

What are the names of the arteries that supply blood to the heart muscle?

Back

Preview of the front of card 4

Card 5

Front

Coronary arteries branch off from the...

Back

Preview of the front of card 5
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