1. Unit 1: Biochemistry, Nutrition, and Digestion Chapter 30: Nutrition and Digestion

2. Chapter 30 Section 30.2 Food and Nutrition

3. Food Energy Measured in calories calorie Dietary Calories
Amount of heat needed to raise the temperature of 1 gram of water 1 degree celsius
Dietary Calories
Also called kilocalories
Equal to 1000 calories
Written with capital C

4. What Do You Use Food For? Energy Build and repair body tissues
There are at least 45 different components in food that the body needs that it can’t make itself
These components are called nutrients

5. Nutrients Water Found in all cells Necessary for chemical reactions
Helps maintain body temperature
1 liter of water a day is necessary to replace what is lost
Can be lost through urination, sweating, breathing

6. Nutrients Carbohydrates
Provide about 4 Cal/gram
Simple carbs provide quick energy
Complex carbs take longer to break down, and provide energy over a longer period of time
Complex carbs provide fiber, or cellulose, which helps move waste through the digestive system
Complex carbs with lots of fiber are healthiest to eat

7. Carbs and Stored Energy
Carbs that are not immediately used can be stored as a complex carb
Converted into glycogen
Stored in the liver, muscles, and brain
Carbs that are not used can also be turned into body fat

9. Nutrients Fats Unsaturated fats are the healthiest to eat
Provide about 9 Cal/gram
Help the body absorb fat-soluble vitamins
Are a part of cell membranes
Provide insulation and protect organs
Can act as hormones
Store energy long-term
Unsaturated fats are the healthiest to eat
Absorbed least by the body

11. Nutrients Proteins Provide 8 essential amino acids
Are the raw materials for many body parts, especially muscles
Also control chemical reactions (enzymes!)
Can act as hormones
Provide about 4 Cal/gram
Provide 8 essential amino acids
Any animal product has all 8
A combination of plant products will have all 8
Lean meat is the healthiest to eat (93% fat or less)

13. Nutrients Vitamins Fat-soluble vitamins Water-soluble vitamins
Organic molecules that the body needs in very small amounts
Needed for chemical reactions
Fat-soluble vitamins
A, D, E, K
Can be stored in fat tissue
Water-soluble vitamins
B complex, C
Cannot be stored, and are lost through urination

15. Nutrients
Minerals
Inorganic molecules that the body needs in very small amounts
Many of them are elements
Water-soluble, and are lost through sweat, urination, and solid waste

17. What Should You Eat? A balanced diet is based on Percent Daily Values
For a 2000-Calorie diet
Calories can change with age, activity level, and age
2200 Cal for female teens, 2800 Cal for male teens
A balanced, healthy diet contains:
Lean proteins for 8 essential amino acids
Complex carbs for energy and fiber
Unsaturated fats in small amounts

18. Chapter 30 Section 30.3 The Digestive System

19. Functions of the Digestive System
Ingestion
Take food into body
Digestion
Mechanical
Physical breakdown of food into small pieces
Chemical
Enzymes break down food into individual nutrients
Absorption
Nutrients absorbed into body
Elimination
Waste is compacted and eliminated

20. The Mouth Teeth Saliva Tongue Pharynx
Incisors, cuspids, and bicuspids cut and tear food
Molars grind food
Saliva
Amylase breaks down starch
Tongue
Forms a bolus, or ball of food
Pushes food into back of throat, or pharynx
Pharynx
Contains epiglottis, which blocks the trachea and prevents choking

21. The Esophagus Connects the pharynx to the stomach
Moves food by peristalsis
Smooth, wave-like muscle contractions

23. The Stomach
Is a muscular sac that continues mechanical and chemical digestion
Chemical digestion
Protein is broken down by the enzyme pepsin
Hydrochloric acid (HCl) also breaks down food
Mechanical digestion
Stomach squeezes and churns food to produce chyme
Chyme is the mixture of food and digestive enzymes

24. The Small Intestine Connects to the stomach
Ends at the large intestine
First section is called the duodenum
Chemical digestion by enzymes continues after food is pushed from stomach
Enzymes are made in the small intestine walls, or are from the pancreas

26. The Small Intestine
Absorption of nutrients into the blood occurs through villi
Villi are fingerlike projections that line the small intestine, and are covered with microvilli
Microvilli are tiny projections of cells on villi that aid nutrient absorption

28. The Pancreas Connects to the small intestine by a duct
Makes and secretes sodium bicarbonate, which neutralizes stomach acid
Makes and secretes enzymes, which break down food
Also produces hormones that regulate blood sugar

29. The Liver and Gallbladder
Liver produces bile
Gallbladder stores bile, and secretes it by a duct into the small intestine
Bile helps break down fats

30. The Large Intestine Also called the colon
Connects to the small intestine
Ends at the rectum
Absorbs water from chyme
Supports colonies of bacteria
Compacts unused nutrients into solid waste
Constipation
Occurs when there is too little water in solid waste
Diarrhea
Occurs when there is too much water in solid waste

32. The Rectum and Anus
Elimination occurs after the large intestine has compacted solid waste into feces
Feces is stored in the rectum
Anus is the muscle that controls release of feces

34. Section 30.1 Organization of the Body

35. Levels of Organization in the Body
Cells
Are the basic unit of structure and function in an organism
Tissues
Are a group of cells that perform a single function

36. Levels of Organization in the Body
Four types of tissues:
Epithelial
Lines interior and exterior body surfaces
Connective
Supports and connects body parts
Nervous
Transmits nerve impulses
Muscle
Moves body parts

38. Levels of Organization in the Body
Organs
Are groups of different tissue types that work together to perform a single function or several related functions
Organ Systems
Are groups of organs that perform closely related functions

43. Homeostasis
Is the relatively constant internal physical and chemical conditions that organisms maintain despite changes in internal and external environments

44. Homeostasis Is maintained through feedback inhibition
Also called negative feedback
A stimulus produces a response that opposes the original stimulus
A thermostat is a good example
Room gets cooler
Heater turns on
Room gets warmer

46. Examples of Homeostasis
Body Temperature
Hypothalamus acts like a thermostat
Triggers the body to shiver when cold, and to sweat when hot
Blood Sugar
Blood sugar (glucose) rises after a meal
Too much blood sugar can damage organs
Body cells absorb glucose, and the liver stores glucose as glycogen
Blood sugar drops to a safe level

47. Section 30.4 The Excretory system

48. Role of the Excretory System
All cells produce waste, and it must be removed from the body, as it is toxic
Excretion is the process by which metabolic wastes are eliminated to maintain homeostasis

49. Structures of the Excretory System
Skin
Excretes water and salts
Lungs
Excrete carbon dioxide
Liver
Converts nitrogen waste into urea

50. Structures of the Excretory System
Kidneys
Filter excess water, urea and metabolic waste from blood
Ureters
Transport urine from kidneys to bladder
Urinary bladder
Stores urine
Urethra
Releases urine outside the body

52. Structure and Function of the Kidneys
Filtration
Is pushing a liquid or a gas through a filter to remove wastes
Uses nephrons
Filtering units of kidneys
Removes water, urea, glucose, salts, amino acids, and some vitamins from blood
Creates liquid filtrate in the nephron from material removed from blood

53. Structure and Function of the Kidneys
Reabsorption
Occurs when water and dissolved substances are taken back into the blood
Also uses nephrons
Removes water, salts, vitamins, amino acids, fats, and glucose from the filtrate in the nephron
Leaves remaining fluid as urine in the nephron

54. Structure and Function of the Kidneys
Urine Excretion
Occurs when urine travels to the collecting ducts in the nephron, and then to the ureters, which connect to the urinary bladder

57. Homeostasis and the Kidneys
When waste builds up in the blood, it increases filtration by the kidneys
The pituitary gland releases antidiuretic hormone (ADH) if blood fluid levels are low, causing the kidneys to reabsorb more water into the blood

58. Kidney Disorders Kidney stones Kidney damage Kidney failure
Calcium, magnesium, and other salts can crystallize in the kidney
Kidney damage
High blood pressure can harm the filtering mechanism of the kidney
Kidney failure
Occurs when kidneys can no longer filter the blood, and will lead to death if untreated

59. Kidney Disorder Treatment
Dialysis
Uses a machine to filter wastes from the blood
Kidney Transplant
Leaves damaged kidneys in place unless they are secreting toxins
Adds donor kidney below old kidney