SENIOR SCIENCE BIONICS Part 2: Circulatory System

1 Explain the relationship between the structure and function of the following parts of the heart – valves – atria – ventricles – major arteries and veins

Circulatory System The blood enters the heart from the body through the vena cava. It enters the right atrium travels through the tricuspid valve and flows into the right ventricle. 1

Circulatory System The muscle surrounding the right ventricle contracts, pushing blood through the pulmonic valve. 2

Circulatory System Blood then travels to the lungs through the pulmonary artery. 3

Circulatory System Here it exchanges carbon dioxide for oxygen. The blood then flows back to the heart through the pulmonary vein into the left atrium. 4

Circulatory System Once the left atrium fills with blood, the bicuspid valve opens to allow blood into the left ventricle. 5

Circulatory System The left ventricle then contracts, pushing blood through the aortic valve into the aorta. 6

Circulatory System From here, oxygen rich blood is circulated around the body, giving oxygen and nutrients to cells. 7

Arteries Vs Veins d

Arteries Vs Veins

a) Blood from the aorta travels to the body T F b) Blood moves into the left atrium through the tricuspid valve T F c) Blood travels through the pulmonic valve from the right ventricle T F d) The vena cava delivers blood to the heart from the lungs T F e) The left side of the heart contains oxygen rich blood T F f) The right side of the heart contains blood rich in carbon dioxide T F g) The pulmonary vein sends blood to the left ventricle T F h) The aortic valve opens, allowing blood from the left ventricle T F into the aorta i) The left ventricle is more muscular than the right ventricle. T F

2 Explain that specialised tissues in the heart produce an electrical signal that stimulates rhythmic contractions of the cardiac muscle

Electrical Activity of the Heart Sinoatrial (SA) node in the right atrium send an electrical signal to the atria, contracting the atria. This sends blood through the valves to the ventricles on both sides of the heart. The electrical impulse from the atria passes to an atrioventricular (AV) junction to the ventricles. The AV junction can be likened to wires between the atria and ventricles. The impulse is slowed here, before being passed to the ventricles. This allows the atria to relax (and fill with blood) before the ventricles contract.

Electrical Activity of the Heart

Electrical Activity of the Heart

Heart Beat The sound of a heartbeat is often described as ‘lub–dub Lub = a long low–pitched sound, is produced by the closing of the valves between the atria and ventricles. Dub = a short, louder and high–pitched sound, comes from the closing of the valves between ventricles and the aorta and pulmonary artery.

Electrocardiograph (ECG)

Electrocardiograph (ECG) Record these electrical impulses Metal electrodes are attached to the skin on a person's arms, legs and chest. The electrodes detect the electrical activity and record it on moving paper or electronically to produce an electrocardiogram (ECG). Doctors can use the patterns produced to help diagnose heart problems.

QRS Wave signals that bring about the contraction of the ventricles. ECG QRS Wave signals that bring about the contraction of the ventricles. P Wave produced by the electrical signals that cause the atria to contract, forcing blood into the ventricles. T Wave recovery wave as the electrical signals spreads back over the ventricles in the opposite direction.

ECG

Identifying Aspects of a Heartbeat Activity Spotlight Senior Science Pg 170

3 Discuss the problems that can result from interruptions to the normal rhythm of the heart

Interruptions to the heart’s normal rhythms Summarise each of the following from the Spotlight textbook (page 171) Heart murmur Ischaemia and fibrillation Tachycardia and bradycardia Damage to the pacemaker region of heart

4 5 Identify that a pacemaker will produce a regular electrical impulse Identify the types of materials used to make pacemakers and the properties that make these suitable for implanting in the body

occasional extra heartbeats Palpitations Palpitations occur when the heart beats too fast or too slow or beats in a irregular manner. This happens when there is a malfunction in some part of the heart's electrical system. These can be felt as: skipping a heartbeat rapid heartbeat pounding in the chest occasional extra heartbeats

Common Problems Requiring Medical Treatment 1 the heart beats too quickly (more than 100 beats per minute) 2 the heart beats too slowly (less than 50 beats per minute) 3 the heart beats irregularly (disorganised electrical impulses)

Treatment

Artificial Pacemaker

Artificial Pacemaker Spotlight Senior Science Page 171-172

Describe the problems that can result from faulty valves in the heart 6 Describe the problems that can result from faulty valves in the heart

Heart Valves

Heart Valves

Faulty Valves Faulty valves can cause symptoms such as: chest pain shortness of breath inability to sleep fatigue and an inability to carry out daily activities swollen ankles abnormally large abdomen.

1 Stenosis Valve cannot open all the way because of disease or injury. Blood has a hard time flowing to the next heart chamber. Heart valves can become calcified (coated in layers of calcium salts.) Narrow opening of the valve.

Insufficiency or regurgitation 2 Insufficiency or regurgitation Valve does not close completely, and blood leaks backwards. The heart has to work harder to pump blood - it has to push harder to get blood through smaller openings or it has to re- pump blood that has leaked backwards.

Insufficiency or regurgitation 2 Insufficiency or regurgitation

7 Describe the properties of materials such as teflon/pyrolytic carbon that make them versatile materials for making artificial body parts, including heart valves

Artificial Valves Spotlight Senior Science Page 172-173

Artificial Valves

8 Describe and explain the effects of a build-up of plaque on the walls of major arteries and veins on blood flow to and from the heart 9 Discuss ways in which plaque could be eliminated or altered to ease blood flow

Heart Health Spotlight Senior Science Page 173

Treatment for Coronary Heart Disease Spotlight Senior Science Page 173-174

THE END Spotlight Senior Science Answer To Think Questions Page 174