Digestive System Flashcards
(5 cards)
Primary vs Accessory Organs
Primary: ones that are actually coming into contact with the food we digest
Accessory: Important for processing the food but do not directly contact the food.
Chemical: breaking chemical bonds
Mechanical: stiring things up to break them apart
Structure of digestive tract
Four layers
Mucosa (epithelial cells)
Submucosal (connective tissue)
Muscularis (smooth muscle with two sublayers: longitudinal (squezze around tube) & circullar (coil around))
Serosa: membrane to encase the whole thing
What are the main steps of the digestive process?
Ingestion: intake of the food via mouth
Digestion: mechanically or chemically breaking down food into their subunits
Movement: food must be moved along the GI tract in order to fulfill all functions; mixing
Absorption: movement of nutrients across the GI tract wall to be delieveref to the cell via the blood
Elimination: removal of the indigestible molecules; defecation (things that your body could not use while urinary tract is waste from products that your body picked through)
Steps of Digestion
The mouth: 32 teeth begin mechanical digestion. Incisors front of mouth, canine tear food, premolars & molars: grind food. Saliva contains enzymes which begin chemical digestion of startches. Salavia is mostly water and has a biocarbonate buffer, mucins, and salivary amylase begins startch digestion. There are three glands: parotid, submandibular, and sublingual
Pharynx: swallowing is the transition from the mouth to the stomach via the esophagus and includes voluntary and involuntary phases. Epagutus prevents food from “going down the wrong tube”. The trachea is in the front and the esophagus is in the back, it begins with a voluntary swallow and pretty much everything else is involuntary. After it goes through the spintectur, it is in the stomach.
Stomach: activily acidifies the enviroment, connects to the brain to tell the body when to eat. Parietal cells and chief cells secrete things into the lumen. Starts to digest protien
Small intestine: Absorbs most nutrients, monomers are there to absorb things. Duodenum is the first section, jejunum is the longest section of your small intestine (where a lot of absorbtion happens), illeum right before the large intestine. Site of protien digestion (peptidases), lipase helps break down fats, increase the surface area of the fats–> bile breaks it apart into small bubbles. Lipase breaks down into monoglycerides and fatty acids. Know what amylase does
What are we digesting?
Carbohydrates (complex sugars, startch): glucose, monosacrides
Lipids (triglyverides & Phosopholipids): glycerol & free fatty acid
Protiens: Amino acids
