digestion. main purpose of the digestive system main goal: get usable nutrients out of our food and...
TRANSCRIPT
Main Purpose of the Digestive System
• MAIN GOAL: Get usable nutrients out of our food and eliminate waste!
• Secrete enzymes into locations where digestion occurs.
• Digest (break down) food particles into smaller molecules.
• Absorb nutrients & fluids.
Nitty Gritty Terms
Intracellular Digestion:- digestion occurs within the cell
Extracellular Digestion: - digestion occurs outside of the cell in body cavities (ex: sm intestine)
Mechanical Digestion:- changing the size or shape of foods
Chemical Digestion:- changing the chemical composition of foods (ex: converting a protein into several amino acids)
Parts is Parts…Mouth
Salivary Glands
Esophagus
Liver
Gall Bladder
Stomach
Pancreas
Small Intestine Large Intestine
Rectum
Anus
Appendix
Mouth• Teeth
– Mechanical Digestion (Physically breakdown food)
• Tongue– Helps mix food w/ saliva– Aids in swallowing
Salivary Glands• Salivary Glands
– Produce saliva which is water and enzymes.
– The water aids in mechanical digestion of all foods.
– Salivary Amylase is the enzyme found in saliva. It digests complex carbs into glucose. This is chemical digestion.
Esophagus• Muscular tube that connects the
mouth & stomach• Peristalsis is a wave-like
contraction of muscles.• Peristalsis moves food from mouth
to stomach even if you are standing on your head!
Peristalsis YouTube Clip
Stomach• Muscular sac about the size of your fist.• Has a mucus lining to protect from HCl
burns.• High acidity of gastric fluid denatures
proteins & exposes peptide bonds• Mixes food, enzymes (pepsin), and HCl
with muscular contractions.– Chemical digestion of protein– Mechanical digestion of all
Small Intestine• Contains intestinal glands that
secrete digestive enzymes.• Most digestions occurs here and all is
completed here.• Site of nutrient & vitamin absorption• Has villi which are small finger like
projections that increase surface area for absorption of nutrients.
Small Intestine…a bit
more!Roughage: Foods that are coarse and not readily digestible by humans that promotes “normal bowel function”
in other words….it is like a brillo pad for our intestines!!
Fruits, veggies and whole grains provide excellent roughage! You
never want “irregular poop”…especially climbing a mountain!
Large Intestine• Short tube w/ wider diameter.
• No digestion occurs here.• Function is water absorption.• Waste moves via peristalsis.
Rectum• Lower end of large intestine.• Semi-solid waste (feces) stay here
until egested via the anus.
WHY?
Accessory Organs:
These are organs that aid in digestions but do not touch
food.Salivary Glands: produce salivawhich contains water and Salivary Amylase.Salivary Amylase is an___________ that digests___________________.
enzymecarbohydrates
Accessory Organs, con’t• Pancreas: produces enzymes that digest every
type of nutrient.• These enzymes are called proteases, amylases
and lipases. What does each digest?• The enzymes are secreted into the small
intestine.
Accessory Organs, con’t• Liver: produces bile.
– Bile is an emulsifier. It does NOT digest fats, but rather breaks them into smaller “globs”. These smaller globs have more surface area for enzymes to do their jobs.
Gall Bladder: stores bile and secretes it into the small intestine.
Summary of Digestive Fun!Name of Organ Makes
Enzymes? Y or N
Touches food?
Y or N
Chemical made there? Nutrient acted upon?
Mouth No Yes None All - M
Salivary Glands Yes No Saliva, Salivary Amylase All – M, Carbs - C
Esophagus No Yes None None
Stomach Yes Yes HCl, Pepsin All – M, Protein - C
Sm. Intestine Yes Yes Enzymes All - C
Large Intestine No Yes None None
Liver NO No Bile Fats - M
Pancreas Yes No Lipase, Amylase, Protease All - C
Gall Bladder No No None None
Gall StonesGall Stones are small, hard particles usually of cholesterol which block the bile ducts.
OMG!
Ulcers:
Damage to the stomach wall due to the mucus lining thinning or being destroyed and the HCl acid burning the muscles of the wall.
Constipation:Feces (poopie) is too hard because too much water has been
removed. “Nuggets” are too hard and dry to pass smoothly through the rectum and anus!
Don’t strain! It’ll give you hemorrhoids!
Diarrhea:
Feces (again…poopie) has too much water due to the large intestine not reabsorbing enough resulting in runny…or really runny poo.