Chapter 3 THE REMARKABLE BODY

1. Chapter 3 THE REMARKABLE BODY Why proper nutrition is important.

2. Summary Organization of the human body Fluids and the cardiovascular system Hormonal and Nervous system Immune system Digestive system Excretory system Storage systems

3. Organization of the Body Cells � the smallest unit of life Tissues � groups of similar cells working as a unit. Organs � two or more tissues form a functional structure. Organ systems � groups of organs working together. Organism (Body) � groups of organ systems working together.

4. Organization of the Body Cells � trillions of self-contained, living entities, each with a specific job and nutrient requirements. Basic requirements for all cells: Water Oxygen �Essential nutrients� � nutrients they cannot make for themselves. Basic structure, fig 3.1

5. FIGURE 3-1: A CELL (SIMPLIFIED DIAGRAM).FIGURE 3-1: A CELL (SIMPLIFIED DIAGRAM).

6. Organization of the Body Genes � DNA Blueprints for the production of proteins Proteins are important structural and functional molecules in living things. Genes affect nutrient utilization and nutrients affect gene function.

7. Organization of the Body Tissues � groups of similar cells that function as a unit. Ex. muscle tissue Organs � 2 or more tissues that make up a unique structure. Ex. heart Organ systems � groups of organs that perform a certain function. Ex. cardiovascular system.

8. Organization of the Body Body systems � groups of organ systems that work together to support body functions. Ex. cardiovascular and respiratory system.

9. Body Fluids and the Cardiovascular System Function: delivery of nutrients, including oxygen, to all of the cells in the body. Delivery of wastes to kidneys and lungs. Body fluids Extracellular fluid � fluid outside cells Blood and lymph Interstitial fluid � filtrate of plasma that bathes cells Intracellular � fluid inside cells

10. Body Fluids and the Cardiovascular System Body fluids cont�d Blood consists of 2 components Plasma � liquid containing proteins and other molecules and� Cells - RBC (red blood cells) carry oxygen to cells. WBC (white blood cells) our immune cells. Platelets � fragments of cells that participate in blood clotting. Lymph � milky fluid similar to plasma.

11. Body Fluids and the Cardiovascular System Cardiovascular system, fig 3.3 Heart � a pump Blood vessels: Arteries carry blood away from the heart Veins carry blood toward the heart and Capillaries connect the two and circulate blood to individual cells. Circulations Two loops in series: 1) Pulmonary loop: lungs ? heart ? � 2) Systemic loop: heart ? tissues ? heart Special Hepatic Portal: Heart ? intestines ? liver ? heart

12. FIGURE 3-3: BLOOD FLOW IN THE CARDIOVASCULAR SYSTEM. FIGURE 3-3: BLOOD FLOW IN THE CARDIOVASCULAR SYSTEM.

13. FIGURE 3-4: HOW THE BODY FLUIDS CIRCULATE AROUND CELLS. The upper box shows a tiny portion of tissue with blood flowing through its network of capillaries (greatly enlarged). The lower box illustrates the movement of the extracellular fluid. Exchange of materials also takes place between cell fluid and extracellular fluid. FIGURE 3-4: HOW THE BODY FLUIDS CIRCULATE AROUND CELLS. The upper box shows a tiny portion of tissue with blood flowing through its network of capillaries (greatly enlarged). The lower box illustrates the movement of the extracellular fluid. Exchange of materials also takes place between cell fluid and extracellular fluid.

14. FIGURE 3-5: OXYGEN�CARBON DIOXIDE EXCHANGE IN THE LUNGS. FIGURE 3-5: OXYGEN�CARBON DIOXIDE EXCHANGE IN THE LUNGS.

15. Hormonal and Nervous Systems Function Communication systems that work together. Monitor and regulate body processes

16. Hormonal and Nervous Systems Hormonal system Hormones (proteins) are secreted by endocrine glands directly into the blood. Regulate many functions including: Appetite/hunger Satiety Digestion Nutrient utilization, ex. pancreas hormones that control blood glucose.

17. Hormonal and Nervous Systems Nervous system � the major communication system Central nervous system: brain and spinal cord - receive information from sensory receptors, interprets and delivers instructions to regulate body functions. Peripheral nervous system � connects brain and spinal cord to the rest of the body.

18. Hormonal and Nervous Systems Brain � nutrition related functions: Hypothalamus regulates hunger/appetite. Cerebral cortex makes us conscious of hunger and causes us to eat. With peripheral nerves regulates digestive tract functions.

19. Hormonal and Nervous Systems Both systems work together to monitor and regulate nutrient delivery to tissues as needed. Ex. Stress response: nerves release neurotransmitters that stimulate endocrine glands that release hormones to speed up metabolism and provide energy. Both systems need nutrients to function properly.

20. Immune System Function: protect the body from invaders (viruses, bacteria, fungi and cancer cells). Organs and cells Skin and mucous membranes � mechanical barriers. Proper function is sensitive to vitamin and other nutrient deficiencies.

21. Immune System Organs and cells cont�d WBCs Phagocytes �roam� around our tissues seeking pathogens which they �eat and destroy�. T-cells: Killer T-cells respond to chemicals from phagocytes and destroy pathogens. Helper T-cells stimulate the immune system. B-cells produce antibodies, proteins that kill or inactivate pathogens.

22. Digestive System Hunger and appetite are regulated by our nervous and hormonal systems but our choice of foods is mediated in our mouths, noses and eyes. Taste, aroma, texture, temperature and appearance + habits affect our choice of food.

23. Digestive System Digestive tract � muscular tube that breaks down food into nutrients and absorbs them into the blood or lymph, fig 3.78. Organs: Primary: mouth, pharynx, esophagus, stomach, small and large intestine and rectum Accessory: salivary glands, teeth and tongue, pancreas, liver and gall bladder.

24. FIGURE 3-8: THE DIGESTIVE SYSTEM.FIGURE 3-8: THE DIGESTIVE SYSTEM.

25. Digestive System Mouth Taste buds on the tongue detect salty, sweet, bitter, sour and savory (umami). Mechanical digestion of food by teeth and tongue. Mixing of food with saliva Swallowing � tongue and pharynx

26. Digestive System Esophagus � passes food from mouth to stomach by peristalsis. Peristalsis � waves of muscular contractions from mouth to stomach, fig 3.9.

27. FIGURE 3-9: PERISTALTIC WAVE PASSING DOWN THE ESOPHAGUS AND BEYOND. Peristalsis moves the digestive tract contents. FIGURE 3-9: PERISTALTIC WAVE PASSING DOWN THE ESOPHAGUS AND BEYOND. Peristalsis moves the digestive tract contents.

28. Digestive System Stomach � mechanical and chemical digestion of food forming a liquid mass = chyme. Small intestine Chemical digestion of food into primary nutrients Absorption of nutrients into the blood/lymph.

29. Digestive System Large intestine Absorbs water and some minerals Compacts undigested components into feces. Rectum � stores feces for elimination, opening held closed by anus (=sphincter composed if muscles).

30. Digestive System Chemical Digestion, Table 3.1 Mouth � some partial digestion of starch by amylase, an enzyme in saliva. Stomach � acid (HCl) and pepsin begin digestion of proteins into peptides.

31. Digestive System Chemical digestion Small intestine Receives bicarbonate from pancreas to neutralize acid from the stomach. Receives bile from the gall bladder to emulsify fats. Bile works like soap to break fats into small droplets.

32. Digestive System Chemical digestion Small intestine Receives enzymes from pancreas that breakdown starches to disaccharides, peptides to amino acids and fats into glycerol and fatty acid chains. Also produces enzymes that breakdown disaccharides to monosaccharides and peptides to amino acids.

33. Digestive System Chemical Digestion Release of enzymes is controlled by the foods eaten. Absorption of nutrients Primarily in small intestine Walls have finger-like projections = villi, with smaller hair-like projections = microvilli. These increase the surface area for absorption of nutrients.

34. FIGURE 3-12: DETAILS OF THE SMALL INTESTINAL LINING. FIGURE 3-12: DETAILS OF THE SMALL INTESTINAL LINING.

35. Digestive System Absorption cont�d Nutrients pass into villi: Water soluble nutrients pass into the blood and are delivered to the liver. Fat soluble nutrients pass into the lymph and enter the blood near the heart. Malnutrition destroys many villi and absorption decreases. Malnutrition also weakens muscles that control the movement of food through the tract.

36. Digestive System OYO (On Your Own) � read �A letter from your digestive system�, pp 83-87.

37. Excretory System Cells produce CO2 as they work. CO2 is transported in the blood to the lungs for elimination. The liver filters toxins and other wastes and delivers them, via the blood, to the kidneys or digestive tract for elimination.

38. Excretory System Kidneys � are composed of smaller units called nephrons that filter blood, decide what nutrients to keep and eliminates the rest in the urine.

39. Storage Systems Hold nutrients for period between meals. Liver and muscle store glucose in the form of glycogen. Between meals the glycogen is broken down to glucose and delivered to cells via the blood. Limited storage!

40. Storage Systems Fat cells (adipose tissue) store excess nutrients as fat and releases it when glucose stores are depleted. Unlimited storage!!

41. Alcohol is it good for you? Source of energy but a non-nutrient. Beneficial and adverse effects � OYO read the Controversy, pp 91-98.