Download Digestive System

Question of the Day
Outline the pathway of digestion from
when it enters the mouth.
Leave room by each structure to add
more information
Digestive System
Chapter 35
Digestive System
Breaks down food to be used as energy
Utilizes both chemical and mechanical process
1. Mouth - chemical and physical digestion
occurs
Teeth - chewing breaks down food into smaller
pieces
 Tongue - moves the food around to be broken
down
 Saliva - contains the digestive enzyme amylase
that breaks down starch therefore utilizing chemical
digestion (works for 30 min after it hits the stomach)
 you make 100-1500 ml of saliva/day
 slightly acidic

Digestive System
Swallowing forces the food
into your esophagus which
connects your mouth to your
stomach
Epiglottis - flap of cartilage
that closes over the trachea
(respiratory tract) when you
swallow to keep food from
entering the lungs
Peristalysis - involuntary,
smooth muscular
contractions that move the
food along the digestive
tract in a wave like action
Teeth – 32 in adults
8 Incisors - teeth with
a single cutting edge.
4 Canines - round
teeth for puncturing.
8 Premolars - teeth
with several cutting
edges for shredding.
12 Molars - teeth with
a flat surface for
grinding.
Parts of a tooth:
•Enamel - the smooth,
hard covering.
•Dentine - the porous
"bone" of the tooth.
•Pulp - the cavity
containing blood vessels
and nerves.
•Cementum - binds the
enamel to the dentine
Stomach - muscular J shaped
enlargement of the GI tract (9
meters)
Esophageal sphincter - keeps
food from going back up
Pyloric Valve - between stomach
and small intestine
3 layers of involuntary muscle
contract to break down food,
this creates a churning of
gastric juice which contains:


1. Enzyme pepsin - digests
proteins into peptides
2. HCL acid - pH 2
Stomach is protected by a
mucous covering
Chyme - digested food in a
thin liquid after 2-4 hours
Small Intestine smooth involuntary
muscle
6 meters long X 2.5
cm
90% of digestion &
absorption of food
molecules occurs
3 Parts:
1. Duodenum - first 25
cm of the small
intestine
2. Jejunum - second
part, ~ 2.2 m
3. Ilium - third part,
longest ~ 3.3 m
*jejunum and ilium are
continuous
Pancreas
“Pancreatic Juice” - Digestive
enzymes and hormones that unite with
the common bile duct and enter the
small intestine. Contains:
1. Insulin to regulate blood sugar
2. Enzymes
 amylase - starch CHO (carbohydrates)
 lipase - fat
 trypsin - protein
 nuclease - nucleic acids
Liver - large, vascular
organ
Produces bile
 Removes toxic substances
from the blood
 Stores Vitamins & minerals
 Destroys damaged RBC

Bile – breaks down fats
into smaller droplets
Gallbladder - stores bile
Cholesterol in bile may
form crystals called
gallstones
Liver
Small Intestine
All these move to the small
intestine for 3-5 hours
Villi - fingerlike projections
enfolded to increase surface
area and allow for absorption of
food molecules into the blood
stream (page 953)
Mesentery - supports the coils
of the small intestine, contains
blood vessels to carry nutrients
away
Large Intestine - 1.5 meters long but 6.5 cm in
diameter





Absorbs water
Leaves wastes & undigested food behind
In-digestable substances
 Mucous
 dead cells
 Bacteria
 synthesizes some B and K vitamins anaerobically
 Breaks down RBC - bilirubin, give feces its color
Cecum - beginning of the large intestine, pouchlike, closed
end called the vermiform appendix (ileocecal valve)
Colon - ascending / transverse / descending / sigmoid
Feces eliminated through the rectum out the anus
Total time 24-33 hours!!!!
Human digestive system length:
An 8.5 meter long piece of rope can be used to illustrate the
length of the alimentary canal.
Approximate lengths for each part of the alimentary canal are
as follows: mouth, 15cm
pharynx, 15cm
esophagus, 35cm
stomach, 30cm
duodenum, 25cm
jejunum, 2.5m
ileum, 3m
colon, 1.5m
rectum, 15cm
If the rope has a diameter of 2.5cm, the size of the small
intestine, the part of the rope representing the small
intestine can be coiled to show how the intestine fits into the
abdominal cavity
Nutritional Needs
Nutrients – substances that provide the body
with substances your body needs, over 40
different, they:
regulate bodily functions
 promote growth
 repair body tissues
 obtain energy

Metabolism – chemical processes by which
your body breaks down food to release energy
Calories – amount of energy (kcal) released
when nutrients are burned (1 g Water – 1o C)
6 Basic Nutrients: Carbohydrates,
Proteins, Fats, Vitamins, Minerals, Water
Carbohydrates – C,H,O, 4kcal/g
Carbohydrates – made up of Carbon,
Hydrogen, Oxygen,
2 types:
1. Simple or single are sugars - glucose is
basic, source of all energy, brain
2. Complex or Starches – cereals, grains,
pasta, breads, crackers, snacks, starchy
vegetables, cooked beans, peas, lentils
Good source of B vitamins, fiber
Serving Size – ½ cup cooked cereal, grain,
vegetables: 1/3 cup of cooked rice or pasta
1 oz of a bread produce or 1 slice of bread
 ¾ to 1 oz of snack foods

Glycogen – starch found in muscles that stores extra
carbohydrates
Fiber – complex carbohydrate found in plants, does no
digest but allows for a healthy digestive system
Fruits – fresh, frozen, canned, dried and juice
Good source of Vitamin C and fiber
Serving size – 1 small fresh fruit 4 oz


½ cup canned or fresh fruit or unsweetened juice
¼ cup of dried fruit
Milk – Serving size 1 cup milk or yogurt
Good source of calcium and protein, more saturated fa
and cholesterol
Non-starchy vegetables – ½ cup cooked, 1 cup raw
Good fiber, dark green and yellow better
Fats – highest energy content 9
kcal/g
Made up of C, H, O in different ratio’s
Unsaturated – liquid at room temperature,
plant
Saturated – solid at room temperature, animal
Cholesterol – waxy fatlike substance found in
animals, causes heart disease, clogs blood
vessels
Serving size – 1 tsp of regular margarine,
butter, oil, 1 tbsp salad dressing
Limit trans and saturated fatty acids, calorie
dense
Proteins - H, C, O, N 4 kcal/g
Long chains of amino acids – 9 essential that must
be gotten from food, body does not produce
Essential for proper growth and repair of tissues
Serving size – 1 oz of meat, fish, poultry or
cheese
 ½ cup beans, peas or lentils (very good for
you!!)
 Choose very lean meats – poultry no skin, fish,
shellfish, game, egg whites, deli meats, some
cuts of beef and pork from butcher
 High Fat meats – cheese, bologna,
hot dog, spareribs
Vitamins – nutrients the body needs for chemical
reactions
Fat soluble – dissolve in fat, can be stored, A,D,
E, K
Water Soluble – dissolve in water, Vitamin C and
B, body cannot store
Deficiency – person does not obtain enough of a
specific nutrient, not common in the US
Minerals - not made by living things, 24 minerals,
need 6 daily, the others in trace amounts (figure
12-9)
Calcium – bone, clotting
Iron – hemoglobin carries oxygen a deficiency is
Water
65% of body is water
Water essential
8 cups of water needed per day
Thermoregulation – keeps cool by sweating
Electrolytes – dissolved substances that regulate
temperature and help maintain homeostasis
(balance)
Dehydration – not enough water, sick, weak,
shock
Malnutrition – nutrient consumption inadequate or
unbalanced, damages body,
Protein-Energy Malnutrition – effects children,
growth, occurs in developing countries
Assessing your Body
Composition
Body Mass Index (BMI) - (weight (lbs)/height (in2))
X703 Example: 125/64 inches2 or 4096 X 703 =
21.45 BMI
< 18.5
Underweight
18.5 – 24.9
Normal
25.0 – 29.9
Overweight
30.0 – 39.9
Obese
>40.0
Extremely Obese
Percent Body Fat – skin fold measurements,
bioelectrical impedance, hydrostatic weighing
How many calories do I need??
Basal Metabolic Rate (BMR) rest
Calculate your BMR by: Weight X 10(11)X
activityX10%
1.Current weight X 10 for women
Current weight X 11 for men
2. Add in energy calories for physical activity:



Light activity = basal needs + 30%
Moderate activity = basal needs + 40%
High activity = basal needs + 50%
3. Add 10% for calories expended during digestion
and absorption
125 lbs X 10 + 1250 X 30% = 375 + 1250 = 1720 X
10% = 1845 kcal per day
* May vary depending on metabolism – increases
Reducing Weight and Fat
Safely
Recognize Eating Patterns - triggers
Tired
 Stressed
 Depressed

Plan healthy strategies –
small portions
 frequent meals
 healthy snacks
 set the table – make it a priority to eat

Exercise – increases calories burned and
endorphins
Diets
Fad Diets – temporary, doesn’t last, limiting
Diet Pills – caffeine, stimulants
Fasting – not eating, lose muscle
High Blood Pressure (hypertension)– sodium free or
decreased
Diabetic Mellitus – insulin enables glucose to go from
blood to the body’s cells insulin injections and eat
balanced diet
Hypoglycemia – low blood sugar (glucose), small
meals
Vegetarian – no meat, rice and beans
Pregnancy – need extra nutrients
Athletics – carbo load,
Food Labels
Calories
Fats, Carbohydrates, Proteins, Sugars
Additives/Preservatives - chemicals to
keep from spoiling
Enriched – nutrients added to replace
those lost in processing niacin,
vitamins, thiamin, iron
Fortified – vitamins, minerals and
proteins, food normally does not have
1.
2.
3.
4.
5.
6.
Title
Serving Size
% Daily value
Nutrients
Summary
Ingredients
The Endocrine
System
Chapter 35.3
Coordination of body systems
by
Chemical control of hormones
I A. Systems that
chemically
coordinate the body:
NERVOUS
ENDOCRINE
Stimuli-response
Rapid response
Short time
Stimuli-response
Slow response
Lasts long time
Both=HOMEOSTASIS
B.Components of the
Endocrine system
1. Glands make ?
Hormones or
chemical
messengers
2. Travel through ?
Blood stream
(Ductless glands)
3. To where ?
Specific Target
Organs
Pituitary
Thyroid
Thymus
Adrenal
Pancreas
Ovaries
Testes
Examples of
hormones & glands...
Mammary glands prolactin
Ovaries make estrogen
Testes make testosterone
Adrenal make adrenaline
IIA.Hypothalamus: Brain
area that controls the
Master Gland: Pituitary
Also controls oxytocin for uterus contraction
& ADH for water balance in the kidneys
Pancreas: Regulates sugar
balance
Insulin =
sugar into
cells
Glucagon
= sugar
leaves
the liver
Adrenal Medulla makes
epinephrine & nor
epinepthrine
Adrenal gland
sits on top of the
kidney
Controls “fight or
flight” response
Superhuman
strength @
adrenaline
Insulin sources for
diabetics :
From
domestic
livestock
Genetically
engineered
bacteria
Feedback
thermostat . . . . . . .
High Blood sugar
Glucagon
Releases
Sugar
From
liver
Low
Blood
Sugar
Cell needs
sugar
Pancreas
makes
Insulin
= Sugar goes into the cell
Feed back loop . .
.....
High Blood
sugar
Pancreas
makes insulin
Sugar enters
the cells
Blood sugar
lowered
Low Blood
sugar
Pancreas makes
glucagon
Sugar leaves the
liver
Blood sugar is
Thyroid: controls
metabolism with
thyroxine hormone
Pituitary gland
controls the thyroid
with TSH
Iodine is important
for the thyroid
tissue
Goiter results from
lack of iodine