Regulation of digestion, diseases and Laboratory work 4

Food excites taste receptors on the tongue; the impulse goes along a sensory nerve to the digestion centre in the medulla, from which motor nerves order salivary and gastric glands to secrete juice. In experiments on dogs I. P. Pavlov showed that juice is secreted not only when food arrives but also at the sight or smell of food or a habitual signal – a conditioned reflex, “appetite juice”. In humoral regulation, hormones made by the stomach and intestine (for example gastrin) and hormones of other glands influence the glands’ work. Digestion slows in heat, so light, liquid dishes, fruit and vegetables suit summer. Eating hygiene: 3–4 times a day at set times, unhurried and well chewed; no distraction by noise, books or phones while eating; washing hands; not overeating. Doctors examine digestive organs with X-ray, endoscope (a thin instrument with a camera) and ultrasound – this cannot be done on one’s own. Everyone’s needs differ; if worried about body shape or weight, talk to a doctor or parents, and do not diet on your own.