Physiology of Eating
Physiology : Eating
• Digestive system – stores and uses energy – Absorption & Fasting – See diagrams • Describe how brain & rest of body controls eating (100%) or role of Hypothalamus
Metabolism – Absorption & Fasting
When we eat we must obtain adequate amounts of carbohydrates, fats, amino acids, vitamins and minerals to construct and maintain our organs, to obtain energy for muscular movement and for keeping our bodies warm. Most of the molecules we eat get ‘burned’ to provide the energy needed. Metabolism consists of two phases; Absorption and Fasting.
Fuel comes from the digestive tract and its presence there is due to eating ….. Digestion Process
Once a meal is absorbed it is often empty until the next meal so a reservoir of fuel is needed. In fact we have two; a short term reservoir which stores carbohydrates and a long term reservoir which stores fat.
In the absorption phase …… In the fasting phase ……. See diagrams
When the body is subject to prolonged fasting, the liver converts fatty acids into ketones which provide energy that can be used by the whole body. Energy can also be extracted from muscle proteins which are broken down into amino acids and converted to glucose. Muscles will waste away but the brain is insured of an energy supply until there is nothing left.
Body : (HEAD – STOMACH – DUODENUM)
Scientists have always had the feeling that hunger originated in the stomach however the systematic search for factors that control eating behaviour really only began in the early 20th century.
• Cannon (1912) : persuaded human subjects to swallow a balloon, attached to a recording device that was inflated when it reached the stomach. The subject couldn’t see the inflation however they were asked to press a key when hunger pangs were felt. The results of the experiment showed that stomach contraction and hunger pangs were roughly coincided giving the suggestion that stomach contractions cause the subject to experience
• Digestive system – stores and uses energy – Absorption & Fasting – See diagrams • Describe how brain & rest of body controls eating (100%) or role of Hypothalamus
Metabolism – Absorption & Fasting
When we eat we must obtain adequate amounts of carbohydrates, fats, amino acids, vitamins and minerals to construct and maintain our organs, to obtain energy for muscular movement and for keeping our bodies warm. Most of the molecules we eat get ‘burned’ to provide the energy needed. Metabolism consists of two phases; Absorption and Fasting.
Fuel comes from the digestive tract and its presence there is due to eating ….. Digestion Process
Once a meal is absorbed it is often empty until the next meal so a reservoir of fuel is needed. In fact we have two; a short term reservoir which stores carbohydrates and a long term reservoir which stores fat.
In the absorption phase …… In the fasting phase ……. See diagrams
When the body is subject to prolonged fasting, the liver converts fatty acids into ketones which provide energy that can be used by the whole body. Energy can also be extracted from muscle proteins which are broken down into amino acids and converted to glucose. Muscles will waste away but the brain is insured of an energy supply until there is nothing left.
Body : (HEAD – STOMACH – DUODENUM)
Scientists have always had the feeling that hunger originated in the stomach however the systematic search for factors that control eating behaviour really only began in the early 20th century.
• Cannon (1912) : persuaded human subjects to swallow a balloon, attached to a recording device that was inflated when it reached the stomach. The subject couldn’t see the inflation however they were asked to press a key when hunger pangs were felt. The results of the experiment showed that stomach contraction and hunger pangs were roughly coincided giving the suggestion that stomach contractions cause the subject to experience