Nutrition and the human body ch3Presentation Transcript
Nutrition and the Human Body Systems and Nutrient Interactions
Plasma, red blood cells, white blood cells, clotting factors, platelets, other components
Transports nutrients, waste products, gases, hormones, and helps with immune response and temperature regulation
Portal vein – transports absorbed nutrients from small intestine to liver (except lipids)
Lymph vessels, lymph nodes, lymph fluid empties into cardiovascular system
Removes foreign substances from blood and lymph
Tissue fluid balance
Fat absorption (first absorbed into the lymphatic system, then carried in the bloodstream)
Into which system are glucose and amino acids absorbed? Which structure carries them to the liver before being dispersed to the rest of the body?
Into which system is lipid absorbed? Which system eventually ends up carrying absorbed lipids?
Brain, spinal cord, nerves, sensory receptors
Regulate and control virtually all body activities
Specific nutrition connections:
Fat coat on myelin sheaths (like “insulation” on live electrical wires)
Some neurotransmitters formed from amino acids
Tyrosine dopamine, epinephrine
Glands and hormones
Thyroid gland, produces thyroid hormone
Pancreas, produces insulin
Adrenal glands, produce adrenaline
Regulates reproduction and cell metabolism
Lymph system, skin, white blood cells, antibodies
Antibodies are made from protein
Nutritional deficiencies quickly lead to immunocompromised state
Why are antibodies and white blood cells part of “specific immunity?”
Why is skin the major component of “nonspecific immunity?”
Why does an elderly man with poor appetite and poor protein intake have an elevated risk for infections?
Kidneys, ureters, bladder
Filter and remove waste and excess water-soluble vitamins and some minerals from blood
Help maintain acid-base balance
Form active vitamin D
Make erythropoietin (hormone that stimulates red blood cell synthesis)
Make glucose from certain amino acids under fasting/starving conditions
Most controlled by nervous system and hormones
Fig. 3.11 Enzymes – protein catalysts that help chemical or metabolic reactions to occur without being permanently changed themselves “ - ase” ending indicates an enzyme (ex: sucrase)
Tongue, taste buds
Flavor vs. taste
Chewing, grinding, etc.
Salivary amylase – begins digestion of starch
Lingual lipase – begins digestion of lipids
Dysphagia – difficulty swallowing, serious health risk for inhaling food
Lower esophageal sphincter (LES)
GERD = gastroesophageal reflux disease
Fig. 3.13 Fig. 3.12
4 cup capacity
Kill bacteria and parasites
Inactivate biologically active proteins (“denatures” them)
Convert digestive enzymes into active forms
Convert minerals into more soluble forms
Chemical digestion, cont.
Pepsin – protein-digesting enzyme
Activated by stomach acid
Digests proteins into di- and tripeptides
Protects stomach from acid and enzymes
Stomach acid protects us from the effects of biologically active proteins (enzymes and hormones) by denaturing them (change shape). When denatured, they are no longer active. Pepsin and other digestive enzymes break these proteins into amino acids, which are then absorbed and used by the body to make new proteins.
Why is the presence of bovine growth hormone in milk, or any other protein-based hormone or enzyme from a plant or animal, not of great concern for human health?
While food proteins are denatured, what happens to pepsin?
Most digestion and absorption take place here
Brush border enzymes
The structural features of this organ increase the absorptive surface over a flat tube by 600 times! That’s the size of a tennis court, covered by your small intestine!
Small intestine, cont.
Liver – produces bile from cholesterol
Gall bladder – stores bile until dietary fat enters small intestine
Pancreas – produces pancreatic juice
Why is there a thick layer of mucus covering the stomach wall?
Why is there NOT a thick layer of mucus covering the small intestine villi and absorptive cells?
What is the purpose of bicarbonate made by the pancreas?
Absorbs some water, vitamins and minerals
Bacterial colonies ferment soluble fibers, produce vitamin K