What does food provide us with?
-energy for body processes
-heat for body temperature regulation
-building blocks for growth and maintenance of body tissues
What is appetite?
the psychological desire to eat certain foods
What are strong cravings even when we are not hungry due to?
What is hunger?
the physiological sensation that prompts us to eat
What is satiety?
the feeling of being satisfied
What region of the brain processes the signals that stimulate hunger and satiety?
What are the 2 types of signals involved in hunger?
nervous and hormonal
Which nutrient has the highest satiety value?
Do carbs or fats have a higher satiety value?
What 3 processes does the food we eat undergo?
digestion, absorption and elimination
What is digestion?
the process of breaking large food molecules down to smaller molecules
What is mechanical digestion?
the physical breakdown of food
What is chemical digestion?
enzymatic reactions that break down large food molecules
What type of digestion takes place in the mouth?
-chemical: salivary amylase (carbs) and lingual lipase (triglyceride)
What types of digestion occur in the stomach?
-mechanical: mixing food w/ gastric juice
-chemical digestion of proteins and fats
What does gastric juice contain?
HCl (to denature proteins), pepsin (to digest protein), gastric lipase (to digest fat)
What protects the stomach lining?
What is chyme?
semi-solid product of mechanical and chemical digestion in the stomach
Chemical digestion in the small intestine
pancreatic enzymes, bile and intestinal enzymes
What are the accessory organs of the GI tract?
liver, pancreas and gallbladder
What is the pancreas role in digestion?
produces digestive enzymes and produces bicarbonate to neutralize chyme
What is the role of bile in digestion?
the process of moving molecules across a cell membrane and into cells of the body
Where does most absorption take place?
small intestine (but a small amount occurs in the stomach)
What are the specialized structures of the small intestine to facilitate absorption?
folds, villi, microvilli and the brush border
what occurs in the large intestine?
-some water and nutrient absorption
-concentration to form feces
How long does it take to form feces?
valve to the large intestine
T/F: hunger is more physiological and appetite is more psychological
T/F: the nerves of the GI tract are collectively known as the enteric nervous system?
T/F: vitamins and minerals are digested in the small intestine
false: vitamins and minerals are not "digested" but broken down or absorbed with fat
T/F: atoms are the smallest unit of life