Regulation of the circulatory organs
Heart work is controlled by nervous and humoral means. Sympathetic nerves speed up and strengthen contractions; parasympathetic nerves (the vagus nerve) slow and weaken them. Humorally, adrenaline and calcium ions strengthen the heart. During exercise impulses from muscle receptors go to the brain, the heart speeds up and blood is redistributed: working muscles receive more. Heart and vessel diseases (high blood pressure, atherosclerosis – narrowing of vessel walls, heart attack, stroke) can often be prevented by a healthy lifestyle: more movement rather than less; not smoking and avoiding smoky air; no alcohol; varied, moderate, low-salt and low-fat food; enough sleep; calming stress. Severe chest pain, shortness of breath, one-sided weakness of the face or arm, and slurred speech are signs that require calling 103 at once. Diagnosis and treatment are made only by a doctor.
Make a “Heart health” poster for your family: 5 rules (activity, food, sleep, smoke-free air, check-ups) and the number 103. Show it to your parents.