9/17/2015By Dr. Rick Woodward1 Today’s Agenda: (1) Journal Questions: What did you have for breakfast today? Was it healthy? Explain your response. *(2)

04/21/23 By Dr. Rick Woodward 1

Today’s Agenda:(1) Journal Questions: What did you

have for breakfast today? Was it healthy? Explain your response.

*(2) Lecture: Digestion, Absorption, Excretion. (Ending on slide 56)

(3) Film: The Diet (Body Story)(4) Homework: Read Chapter 49.

Digestion & Nutrition: 1. What is a calorie?

A calorie is defined as a unit of energy supplied by food.


Digestion & Nutrition 2. What is normal daily caloric intake?

a. Teenage Girls, Active Women, Most Men: 2,000 Calories

per day

b. Teenage Boys, Active Men: 2,400 Calories per day


Digestion & Nutrition


Obesity Definition:A. Obesity is defined by a Body Mass

Index (BMI) of greater than 30% with a body fat percentage of:

(1) Greater than 28% for males.

(2) Greater than 36% for females.



Who’s Big? (NIH Study 2010)A. Prevalence of overweight and

obesity in the United States 2010

(1) Adults (20 years of age and up)

a. 32.9% of U.S Adults are

obese.

(2) Children (Ages 2 – 19)

a. 31.9% are overweight and

obese.


The Children of 2010A. From 2006 - 2010, millions of

teenagers and young adults joined the ranks of clinically obese.

B. There is an increased incidence in type II diabetes in teens.

C. Even our pets are overweight, 25% of dogs and cats are heavier than they should be.


Fat Animals in the Wild


The Children of 2010 D. Twenty years ago, 5% of American

kids were overweight.E. Today 20% are overweight and

another 15% are headed that way.F. In 1969, 80% of kids played sports

everyday; today only 20% play sports everyday.

G. By age 17, a child has spent 38% more time in front of the television or computer than in school.

H. 80% of a teenager’s calories come from sodas.


Fruit Juices vs. Soft Drinks A. Look at sugar content:

(1) Which has the most grams of total sugar?


Who’s Big? (CDC 2010)B. Obese children and

adolescents are more likely to become obese as adults.

(1) One study found that approximately 80% of the children who were overweight at ages 10 – 15 years of age were obese adults at age 25.


Who exercises? A. The proportion of youth (18 years

of age) who report engaging in no physical activity is high, and the proportion increases with age.


Why is this happening?

A. We eat too much high-calorie food and we do not burn it off with enough exercise.

B. 3,500 calories = 1 pound of fat; It is very easy to gain 1 pound of fat in a week.


Fat Cells A. The amount of fat cells you are born with

will probably be the same number when you die.

(Only the size of the cell increases or decreases depending on weight gain and weight loss)

B. There are 3 times in life when you can increase the number of fat cells your body has:(1) The Toddler Years(2) Puberty(3) Third Trimester of Pregnancy


First Law of ThermodynamicsA. Calories In = Calories Out

B. If the calories you take in are greater than the calories you expend (exercise) you will get fat.

C. Excess calories are stored as fat.

D. Average daily caloric intake varies:

2,000 – 2,500 calories per day.


Role Models???


What did Sushi A say to Sushi B?


Was up B? (Wasabi)



Digestion, Absorption & Excretion

By Rick Woodward


Digestion Starts in the Mouth

I. The Mouth

1. Secretion of saliva upon the sight or smell of food.

A. Lubricates each morsel with mucus to make passage easier.

-Saliva contains amylase, mucus, and lysozymes.


The Mouth

B. Contains amylase, an enzyme that breaks down starch (carbohydrate chains).

-Starch digestion begins in the mouth.


The Mouth

C. Lysozymes break into the cell walls of bacteria that are on or in your food.


The Mouth

D. The body manufactures 1-2 quarts of saliva a day.

E. Saliva is mostly water and it is weakly alkaline (basic) with a pH of 7.4


The Mouth

2. Chewing creates smaller particles whose increased surface area allows digestive enzymes to access more surface area of swallowed food.

(Mastication)


The Mouth3. The tongue assesses

the amounts and types of food found in saliva.

a. Tastes include:

(1) Sweet

(2) Salty

(3) Sour

(4) Bitter


The Esophagus

II. The esophagus is a tube through which your food travels to your stomach.

A. Food is transported with a peristaltic (pumping) motion.


The EsophagusB. An opening called the

glottis is covered by a flap of tissue called the epiglottis.


The Esophagus

C. The epiglottis prevents choking by covering the trachea (wind pipe/breathing tube) when swallowing.


The EsophagusD. The lower esophageal valve

prevents backflow of the stomach’s contents from going back into the esophagus.

(Heartburn/Acid Reflux)


The StomachIII. The stomach secretes mucus,

hydrochloric acid, pepsin, lipase, and an intrinsic factor which is necessary to activate and absorb Vitamin B-12.


The StomachA. Digesting protein using:

1. Stomach acid juices, like hydrochloric acid (HCl) pH = 2.

a. Pepsin, an enzyme, works directly on large proteins.

b. Protein digestion begins in the stomach.


The StomachB. The average capacity of

the stomach is one liter.


The StomachC. Food stays in the stomach for

about 2-3 hours.


The Stomach

D. Fatty meals or solid foods take longer to digest than liquids and low-fat meals.

-Lipase, an enzyme, starts the digestion of certain fats.


The Small Intestine

IV. The Small Intestine (Duodenum): 95% of all digestion and nutrient absorption takes place here.


The Small IntestineA. Food entering the small

intestine from the stomach is strongly acidic.

-Secretions from the pancreas alkalize the food coming in from the stomach.

-Small Intestine has a pH = 8.3


The Small Intestine B. Can be up to 10 feet long (referred

to as “small” because of its small diameter.)


The Small Intestine

C. Food may remain in it from 4-10 hours.

D. Most nutrient absorption occurs within the small intestine.


The PancreasV. The Pancreas supplies the following

enzymes to the duodenal are of the small intestine: (1) Trypsin, an enzyme, for protein digestion.(2) Amylase, an enzyme, for starch digestion.(3) Lipase, an enzyme, for fat digestion.(4) Bicarbonate, for acid neutralization.


The LiverVI. The Liver supplies the

duodenum with bile.

A. Bile envelopes fat droplets in a fluid for intestinal absorption.

B. Bile emulsifies fats.

C. Up to one liter of bile is stored in the gall bladder.


The Large Intestine

VII. The large intestine can be up to six feet long.

A. Can hold food for as long as three days.


The Large IntestineB. Colonies of helpful bacteria are

permanent residents.

(1) They aid in the digestion of plant matter.

(2) Bacteria produce vitamins: B12, Riboflavin, Thiamine, and Vitamin K.


The Large IntestineC. Water is removed from food in

the large intestine. (water absorption)

(1) Some diseases that affect the large intestine can cause diarrhea.

(2) Waste matter is packaged for removal.

a. About ½ of waste is dead bacteria.


Overview of Digestive SystemA. Something happens to

your food through each part of the digestive tract.

B. Nutrients become available and transported throughout your body via the circulatory system (blood).


Excretory SystemA. Your excretory system works in

a similar way to the equipment that purifies water.

B. Your excretory organs are:(1) Kidneys(2) Lungs(3) Skin

C. The organs help your body get rid of waste products.


Excretory SystemD. The amount of water in blood is

important to maintain:

(1) Normal Blood Pressure (120/80)

(2) Movement of Gases

(3) Excretion of Solid Waste.


Excretory SystemE. Filters out nitrogen wastes

and helps maintain osmotic balance.


Excretory SystemF. The main excretory organs

are two kidneys; fist size, bean-shaped structures that lie near the dorsal abdominal wall.


Excretory SystemG. Kidneys filter blood that has

collected waste products from cells.

-If waste products build up, they act as poisons to the body cells.

(1) Each kidney is made up of about 1 million nephrons, the tiny filtering units of the kidney.


Excretory SystemH. Each nephron is made up of a

cup-shaped Bowman’s capsule, which narrows into a long, coiled tubule.

(1) In the center of each Bowman’s capsule is a mass of capillaries called the glomerulus.

(2) A glomerulus forms from a small artery that branches from one of the two renal arteries.


Excretory SystemI. The Filtering Process:

1. Blood entering the kidney contains needed materials being transported to body cells, plus urea and excess salts.


The Filtering Process

2. The blood acquires urea when it passes through the liver, which converts ammonia to urea.

a. Urea is less toxic than ammonia.

b. It conserves water because it requires less water for excretion.


The Filtering Process3. The continuous flow of blood into the

kidneys forces the liquid out of the cup portion of Bowman’s capsule and into the tubule.

a. In the tubule is where the actual filtering process takes place.

b. 99% of the water passing through the kidneys is reabsorbed.

c. What remains in the collecting duct of the nephron is: urea, salts, and a small amount of water.

-This is called urine.


The Filtering Process4. Urine passes from the

collecting duct to the ureter, which conveys urine to a muscular storage sac, called the urinary bladder.


The Filtering Process

5. When the bladder becomes filled, a muscular valve relaxes, and urine is excreted and discharged through the urethra.

With the remainder of class time:1. Answer the vocabulary

activity in your packet.

2. Color in sections of the digestive system in your packet.

3. Label the organs of the digestive system on page 1 of your packet

By Dr. Rick Woodward 57

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9/17/2015By Dr. Rick Woodward1 Today’s Agenda: (1) Journal Questions: What did you have for breakfast today? Was it healthy? Explain your response. *(2)