1. Chemistry plays an important role in the study of nutrition by examining the organization of atoms, molecules, cells, tissues, and organ systems that make up the human body.
2. Nutrients from food are broken down and absorbed through a series of biological and chemical processes along the gastrointestinal tract and circulated through the cardiovascular and lymphatic systems to provide energy and building blocks to cells.
3. The kidneys and liver help eliminate cellular waste and metabolize nutrients circulating in the bloodstream before they are used by tissues and organs throughout the body.
2. How Does Chemistry Apply to
the Study of Nutrition?
• Organization
• Atoms → simple molecules → complex
molecules → cells → tissues → organs → organ
systems
• Made of and fueled by nutrients in food
6. How Does Chemistry Apply to
the Study of Nutrition?
• Reduction-oxidation
(redox) reactions
• Oxidation
• Loss of electrons
• Reduction
• Gain of electrons
7. How Does Chemistry Apply to
the Study of Nutrition?
• Simple molecules
• Elements – 20 essential for human health
• 6 elements account or 99% of total body weight
• Chemical bonds
• Compounds
• Molecular formulas
9. How Does Chemistry Apply to
the Study of Nutrition?
• Complex molecules
• Examples
• Assembly and disassembly
• Condensation
• Hydrolysis
• Acid-base chemistry
• pH scale
– Basic, neutral, acidic
– Buffers
11. How Do Biological Molecules Form
Cells, Tissues, Organs, & Organ
Systems?
• Cells
• Organelles, cytoplasm, Extracellular and
intracellular environments
• Cell membranes
• Selectively permeable
• Transport mechanisms
– Passive transport mechanisms
– Active transport mechanisms
12. How Do Biological Molecules Form
Cells, Tissues, Organs, & Organ
Systems?
• Passive transport mechanisms
• Simple diffusion
• Facilitated diffusion
• Membrane-bound transport proteins
• Osmosis
• Solutes
14. How Do Biological Molecules Form
Cells, Tissues, Organs, & Organ
Systems?
• Active transport
mechanisms
• Carrier-mediated
active transport
• Requires ATP &
transport proteins
• Vesicular active
transport
• Endocytosis
• Exocytosis
Carrier-mediated active transport
19. How Do Biological Molecules Form
Cells, Tissues, Organs, & Organ
Systems?
• Organs
• Two or more different types of tissues
• Organ system
• Communication systems
• Nervous system
– Neurotransmitters
• Endocrine system
– Hormones
• Negative feedback systems
21. How Does the Digestive System
Break Down Food into Absorbable
Components?
• Gastrointestinal tract
• Hollow tube from mouth to anus
• Organs
• Mouth, esophagus, stomach, small intestine, and
large intestine
• Accessory organs
• Three important functions
• Digestion, absorption, and egestion
23. How Does the Digestive System
Break Down Food into Absorbable
Components?
• Tissue layers
• Mucosa
• Mainly epithelial cells
• GI secretions
• Lifespan
• Submucosa
• Rich supply of blood vessels
• Lymphatic vessels
• Network of nerves
25. How Does the Digestive System
Break Down Food into Absorbable
Components?
• Tissue layers
• Muscularis
• Two layers of smooth muscle
– Longitudinal layer and circular layer
• Mixing of food mass with digestive secretions
• Serosa
• Secretes fluid that lubricates digestive organs
26. How Do Gastrointestinal Motility and
Secretions Facilitate Digestion?
• Transit time
• 24 to 72 hours
• Factors affecting transit time
• Sphincters
• Named according to anatomical locations
28. How Do Gastrointestinal Motility and
Secretions Facilitate Digestion?
• GI motility
• Mixing and propulsion of material
• Muscular contractions
• Two types of movement
• Segmentation
– Mixes and propels food
• Peristalsis
– Vigorous propulsive movements
33. How Do Gastrointestinal Motility and
Secretions Facilitate Digestion?
• Three regulatory control mechanisms
• Neural
• Enteric nervous system
– Sensory receptors: chemoreceptors &
mechanoreceptors
• Central nervous system
• Hormonal
• GI hormones
– Influence desire to eat
35. How Does the GI Tract Coordinate
Functions to Optimize Digestion &
Nutrient Absorption?
• Three phases of digestion
• Cephalic phase
• Before food enters mouth
• Gastric phase
• Arrival of food in stomach
• Intestinal phase
36. How Does the GI Tract Coordinate
Functions to Optimize Digestion &
Nutrient Absorption?
• Digestion begins in the mouth
• Mastication
• Saliva
• Taste sensation
• Salty, sour, sweet, bitter, umami
• Olfactory and gustatory cells
• Swallowing
• Phases
• Bolus
38. How Does the GI Tract Coordinate
Functions to Optimize Digestion &
Nutrient Absorption?
• Esophagus
•
•
•
•
Delivers food to the stomach
Dysphagia
Gastroesophageal sphincter
Transit time
• Less than 10 seconds
39. How Does the GI Tract Coordinate
Functions to Optimize Digestion &
Nutrient Absorption?
• Stomach
• Regions
• Fundus, body, and antrum
• Pyloric sphincter
• Storage
• Rugae
• Mixing food with gastric secretions
• Third layer of smooth muscle
• Chyme
45. How Does the GI Tract Coordinate
Functions to Optimize Digestion &
Nutrient Absorption?
• Regulation of gastric emptying
• Influential factors
• Volume
• Consistency
• Composition of chyme
• Influence of small intestine
• Cholecystokinin (CCK)
46. How Does the GI Tract Coordinate
Functions to Optimize Digestion &
Nutrient Absorption?
• Small intestine
• Chemical digestion and nutrient absorption
• Regions
• Duodenum, jejunum, and ileum
• Lining of small intestine
• Plica circulares
• Villi
– Enterocytes
• Microvilli
• Lacteal
49. How Does the GI Tract Coordinate
Functions to Optimize Digestion &
Nutrient Absorption?
• Digestion in the small intestine
• Regulated by hormones
• Secretin and CCK
• Pancreatic juice
• Bile
• Produced in liver; stored in gallbladder
• Digestion of fatty foods
• Enterohepatic circulation
• Enzyme facilitation
51. The Role of the Liver and
Gallbladder in Digestion
52. How Does the GI Tract Coordinate
Functions to Optimize Digestion &
Nutrient Absorption?
• Nutrient absorption
• Passive and active transport mechanisms
• Stomach absorption
• Small intestine absorption
• Entry into and exit from enterocyte
• Bioavailability
• Influential factors
54. How Does the Body Circulate
Nutrients & Eliminate Cellular Waste
Products?
• Transport
• Circulatory system
• Absorption from small intestine
• Water-soluble nutrients
• Circulate to liver in bloodstream
55. How Does the Body Circulate
Nutrients & Eliminate Cellular Waste
Products?
• Cardiovascular system
• Two loops
• Systemic circulation
• Delivers blood to all the body’s organs except
lungs
• Capillaries
• Exchange of materials, nutrients, and gases
• Arterial and venous vascular systems
• Similarities and differences
57. How Does the Body Circulate
Nutrients & Eliminate Cellular Waste
Products?
• Cardiovascular system
• Pulmonary circulation
• Circulation between the heart and lungs
• Pulmonary arteries and veins
59. How Does the Body Circulate
Nutrients & Eliminate Cellular Waste
Products?
• Lymphatic system
• Circulates fat-soluble nutrients
• Eventually delivers them to cardiovascular
system
• Route initially bypasses the liver
60. How Does the Body Circulate
Nutrients & Eliminate Cellular Waste
Products?
• Kidneys
• Cellular waste products
• Nephrons
• Filtration
– Initially removes substances from the blood
• Reabsorption
• Causes of impaired kidney function
• Hemodialysis
• Formation of urine
62. What Is the Role of the Large
Intestine?
• Major functions
• Absorption and reabsorption
• Microbial action
• Storage and elimination
• Four general regions
• Cecum
• Colon
• Rectum
• Anal canal
64. What Is the Role of the Large
Intestine?
• Cecum
• Appendix
• Ileocecal sphincter
• Colon
• Ascending, transverse, descending
• Anal canal
• Internal and external anal sphincters
65. What Is the Role of the Large
Intestine?
• Absorption and reabsorption
• Haustral contractions
• Absorption
• Some water and electrolytes
• Reabsorption
• GI secretions
• Feces
• Diarrhea and constipation
66. What Is the Role of the Large
Intestine?
• Microbial action
• Intestinal microbiota
• More than 400 species
• Important roles
• Probiotic and prebiotic foods
• Egestion
• Defecate
67. Irritable Bowel Syndrome &
Inflammatory Bowel Disease
• Inflammatory bowel disease (IBD)
• Autoimmune disease
• Examples
• Ulcerative colitis
• Crohn’s disease
• Irritable bowel syndrome (IBS)
• Functional disorder
• Underlying cause has not been determined