12. Digest and ExcretoryBT ed_2009

12. Digest and ExcretoryBT ed_2009 - Exercises 12 & 13...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
1 The Digestive System- Fuel for Life The Excretory System
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 The Digestive System The Vertebrate Digestive System WHY must we eat to live??? Provides chemical energy for cellular respiration Provides “building block” materials for cells Provides essential nutrients that cells cannot produce WHAT do we eat to live??? Organic molecules Carbohydrates Lipids Proteins Nucleic Acids
Background image of page 2
3 A journey through the vertebrate digestive tract… There are 4 stages to digestion: Ingestion This is the stage of digestion that we play an active role in… EATING!!! Involves the mechanical breakdown of large pieces of food Digestion The chemical breakdown of organic macromolecules into their “building blocks” or monomers Absorption The cellular absorption of organic monomers Elimination Undigested materials are purged from the system
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Ingestion Structures: Oral cavity (mouth) - Food is broken up (increases surface area for enzymatic digestion) Produces salivary amylase to begin the chemical breakdown of carbohydrates (digestion starts here!) Tongue - Tastes food Manipulates food to prepare for swallowing (involved in chewing and forming a ball, or bolus, to be swallowed) Salivary Glands - Produce saliva pH buffer Contains antibacterial agents Produce Salivary Amylase Enzyme that begins to breakdown carbohydrates
Background image of page 4
5 Ingestion Cont. Structures: Pharynx - The junction of the esophagus and trachea (wind pipe) The trachea must be closed while swallowing. Esophagus - Tube that directs food from the pharynx to the stomach via peristalsis ( waves of involuntary muscle contractions)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 Digestion Structures: Stomach - Food storage organ Lining is highly folded with pits leading to gastric glands that secrete a mixture of digestive fluids. HCl
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 30

12. Digest and ExcretoryBT ed_2009 - Exercises 12 & 13...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online