Download Chapter 36 – Digestive and Excretory System

Chapter 36 – Digestive and Excretory System
2/2 Classwork – Copy vocabulary terms from the board
Homework 2/2 (due Wednesday)
Keep a record of what you eat (breakfast, lunch,
dinner) on Tuesday and bring in on Wednesday.
Food and Energy
Nutrients are substances that the
body requires for energy, growth,
repair and maintenance.
Fuel
Other Essential Nutrients
Carbohydrates
Vitamins
Proteins
Minerals
Fats
Water
Calories vs. calories
When the body breaks
down food through
digestion, the chemical
bonds in nutrients are
broken and energy is
released.
The energy release when bonds break is measured in calories. 1000
calories is equal to 1 Calorie (information found on food labels).
Calorie Determination
Calories are determined by a process called
calorimetry.
Energy Requirements
The body needs energy to carry out both
voluntary (Running, swimming, biking) and
involuntary (breathing, growing, blinking)
activities.
Exercise
Calories
When you consume more calories than you burn, those calories get store in
the body as fat.
Body Fuels
Carbohydrates
Simple sugars (Glucose)
Found in fruits, honey and onions
Complex Sugars (starch and cellulose)
Found in fruits,
vegetables, cereal grains,
potatoes, and corn.
Body Fuels, cont.
Proteins
Essential Amino Acids
(found in foods)
Amino Acids (made
in the body)
Proteins
Enzymes
Antibodies
Muscles
Eggs
Milk
Fish
Poultry
Beef
Contain all of the essential
Amino acids
Only some are found in plants
Body Fuels, Cont
Fats (One type of lipid)
Used for storing energy, padding and insulating
organs, making hormones and cell membranes,
and dissolving fat soluble vitamins
Essential Nutrients
Water
Regulates body temperature, and transports gases, nutrients and
wastes.
Vitamins
Fat soluble vitamins – A, D, E, K
Stored in body fat and can become toxic in large amounts
Water soluble vitamins – B, C
Excess amounts are excreted in the urine and can be replaced
by the diet.
Minerals
Naturally occurring substances that are not made by the body (Na, K, Fe, Ca)
These substances are needed for nervous system function, muscle
contraction, transporting oxygen in the blood and normal immune function.
Healthy Eating Habits
Nutritional and Health
Body Mass Index (BMI)
Healthy Adult Weight Range (BMI = 18.5-25.0)
BMI 
(Weight..........
in pounds)
..........
......
(Height in inches)2
x703
Excess body fat can result in increased risk of:
Heart disease
Osteoarthritis
Type II diabetes
Eating Disorders
Anorexia
Obsession with being thin
Bulemia
Binge eating followed by behaviors to
reduce weight (vomiting, fasting, overexercising)
Abnormal eating habits may result in
dehydration, fatigue, organ failure and death.
Breaking Down Food Into Nutrients
Digestion
The body takes in food, breaks it down into
molecules that the body can use, and gets rid of
undigested molecules and waste.
Chemical Digestion – breaking of chemical bonds
Complex carbohydrates
Proteins
Fats
Simple sugars
Amino acids
Fatty Acids
Mechanical Digestion – Physical breakdown of food
Chewing and churning
Starting Digestion – Mouth
Mouth
Mechanical breakdown of food by teeth
Chemical breakdown of food by saliva
 Contains amylase – an enzyme that breaks down
starches
Swallowing
 The epiglottis covers the trachea and food moves into
the esophagus
 Peristalsis begins in the esophagus
Starting Digestion – Stomach
Stomach
Chemical breakdown of proteins by Gastric
juices (HCL and pepsin)
HCL unfolds proteins
Pepsin breaks bonds in proteins to form amino acid
chains
Mechanical breakdown occurs as the
stomach churns food and mixes it with
gastric juices
Absorbing Nutrients
Absorption of nutrients mostly takes place
in the small intestine and is aided by
secretions from the liver and pancreas.
Liver- Secretes bile that breaks fat
globules into tiny fat droplets and aids in
the absorption of vitamins A, D, E, and K
Gallbladder – Stores bile
Pancreas – Secretes lipases to
breakdown fat droplets
Other Important Functions of the Liver
and Pancreas
Homeostasis – Blood sugar regulation
The liver converts extra sugar into glycogen (a stored
source of energy). When energy is needed, the liver
breaks down glycogen and releases glucose. The
pancreas makes insulin that regulates the conversion of
glycogen to glucose.
Storage and Detoxification
Besides glycogen, the liver stores fat soluble vitamins
and iron. It also, removes poisons from the bloodstream
and monitors the production of cholesterol.
Small Intestine
The small intestine further
breaks down food and
reabsorbs nutrients through
the villi and microvilli that
cover its lining.
Capillaries in the villi,
transport nutrients to the
blood stream.
Removing Waste
The Large Intestine (No digestion occurs here)
Water and minerals are absorbed
Vitamins B and K are synthesized here by
bacteria
Bacteria transform undigested material into
feces
Excretion
Osmotic (amount of dissolved particles) and pH
balance of the blood is maintained through
excretion.
Excretory Organs
Skin
Lungs
Kidneys
removes excess water, salts and nitrogen
remove carbon dioxide
primary excretory organs that remove all of the
above and other cellular wastes.
Water
Most chemical reactions must take place in water
Water absorbs and distributes heat
Water transports gases, nutrients and wastes in
and out of cells
DRINK WATER
A health person should drink at least 2.5qt of water
each day to replenish the water lost through
excretion
Cleaning the Blood
Kidneys contain Nephrons that carry out 3
main functions:
Filtration of blood (Glomerulus)
Reabsorption of water and other nutrients (renal tubule)
Secretion of wastes, toxins and water (collecting ducts)
Urinary Excretion
The resulting product of filtration, absorption
and secretion is Urine.
Urine flows through:
Ureters
Bladder
Urethra
Kidney Disease
Kidneys are vital to maintaining homeostasis,
so damage to the kidneys may eventually
become life threatening.
Most common causes of kidney damage:
Infection
Diabetes
High blood pressure
Autoimmune diseases
Treatment for Kidney Disease
Dialysis (not a cure)
A process for filtering blood to remove
substances from the blood.
Kidney Transplant