Double circulatory system

Blood flowing to and from the lungs

Blood flowing to and from all other organs in the body. Including, heart muscles.

Draw and label a diagram of the heart. Include the following labels: Aorta Semi lunar (aortic) valve Left ventricle Atrioventricular (mitral) valve Left atrium Pulmonary vein Vena cava Right atrium Atrioventricular (tricuspid) valve Right ventricle Semi lunar (pulmonary) valve Pulmonary artery Septum

Causes and consequences of occlusion (blockage) of the coronary artery. Development of fatty tissue (aka atheroma) in the artery wall next to the endothelium. Risk factors include: -High concentration of low density lipoproteins in the blood, consumption of trans fats (damage endothelium, chronic high blood pressure due to smoking/stress -Chronic high blood glucose concentration (diabetes, poor diet), infection of the artery wall (Chlamydia pneumoniae),

Control of heart rate Cardiac muscle contracts and relaxes spontaneously – myogenic muscle contraction Sinoatrial node (SA) in the right atrium. Natural pacemaker, ‘sends out’ electrical signals every 0.8 sec. Contracts both atria. Atrioventricular node (AV) also in the right atrium. Receives signal, sends a second signal 0.1 sec. later. Contracts ventricles. The medulla area in the brainstem, sends signals to the SA, via the cranial nerve to alter the heart rate depending on body conditions. E.g. exercise.

Intent and consequences… Ethical decisions often faced by doctors who are asked by a patients family to withdraw treatment to ‘ease a patients suffering’, this can result in the death of the patient. Euthanasia is illegal in many countries, but should we always prolong life if we can… these are important questions which cannot always be answered easily.

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Aka adrenaline Hormone, produced by the adrenal glands. Causes an increase in the heart rate – fight or flight hormone.