Transcript Digestion - Hicksville Public Schools / Homepage

OBJ: Given video, notes, activity sheet SWBAT explain the functions
of the digestive system and the role of the mouth esophagus and
stomach play in digestion with 70% accuracy.
BRING IN TEXTBOOK
DN: Distribute SMSD Review Sheets (**EXAM**)
HW Check- Skin Booklet; Video: Digestive System
ACT: Introduction to Digestion (notes)
Text, read p. 60-65; Work on Digestive Process
Begins Booklet
HW: Complete Digestive Process Begins Booklet; Work
on SMSD Review Sheets; SMSD EXAM, Wednesday, Feb
25; Winter Recess NYSSAE 2008 Exam (on scantron, due
Feb 23)
Digestive Process Begins Notes
Digestive System Functions:
1. breakdown food into nutrient molecules
2. absorption of nutrient molecules
(into Circulatory System)
eliminate solid waste (Excretory System)
Absorption: nutrient molecules pass through wall of
small intestine into bloodstream (Circulatory
System)
Digestion Notes
Digestion: breakdown food into nutrient
molecules. Two (2) types of digestion:
– Mechanical Digestion: physical breakdown by
chewing (mouth) and churning (stomach)
– Chemical Digestion: chemicals (enzymes,
acids) breakdown food. Example: enzymes in
mouth breakdown starch into sugars, acids in
stomach breakdown proteins
Digestion Notes
• Mouth: digestion begins; saliva contains
water, DNA, enzymes (which breaks down
starches). Teeth physically breaks down food.
Teeth Types:
incisors: cut into pieces
canines: tear, slash into pieces
molars: crush and grind into powder
Enzyme: protein that speed up chemical
reactions
Digestion Notes
• Esophagus: muscular tube connecting
mouth to stomach.
• Epiglottis: flap (sheet) of tissue which
seals off trachea (windpipe) to lungs.
• Peristalsis: involuntary muscular
contractions that push food toward
stomach and through intestines.
Digestion Notes
• Stomach: holds/stores food; where
digestion begins (protein breakdown):
mostly mechanical digestion (churning) but
some chemical digestion (acids, enzymes)
occurs.
Digestive Juice: HCL acid and pepsin
(enzyme).
Pepsin: enzyme that breaks down protein.
HCL Acid: chemical that breaks down solid
food into paste (chyme); kills bacteria
Mucus: covers stomach wall which protects
stomach against ulcers (= holes in stomach
wall)
Final Digestion & Absorption Digestion Begins
Mouth
Esophagus
Stomach
Liver
Gallbladder
Pancreas
Small Intestine
Large Intestine
Rectum
Anus
Digestion Notes
Stomach cells are quickly replaced if
damaged or worn.
Chyme: solid food is broken down into thick
liquid paste
Next Lesson: in small intestine, final
digestion and absorption occurs