Week 7 Flashcards
(31 cards)
What is the Digestive system?
- Converts food into raw materials to fuel body cells.
Function: Breaks food down into nutrient molecules as it absorbs nutrient molecules into the blood and excretes indigestible remains
What is Alimentary/Gastrointestinal Tract?
Digests food by breaking it down into smaller fragments
What are Accessory Organs?
Organs that aid in digestive process
Process Of Digestion
1.) Ingestion: Taking in food via the mouth
2.) Propulsion: Moving food along the GI tract through Peristalsis
3.) Mechanical Digestion: Physical breakdown of food to increase surface area so it can be digested by enzymes. For Ex; Chewing (Mastication)
4.) Chemical Digestion: Complex for molecules broken down into their chemical building blocks by enzymes
5.) Absorption: Passage of digested end products, along with vitamins, minerals and water
6.) Defecation: Indigestible substances are eliminated from the body in the form of faeces
What do Tongue/Hard Palate and Soft Palate do during digestion process?
Tongue: Facilitating movement of food during mastication/ Forms Bolus
Hard Palate: Provide space for tongue to move freely and rigid surface help form bolus
Soft Palate: Responsible for Gag reflex/ Ensure food and air go through the right passage to avoid choking
Stomach Cell Types 1: Mucosal Lining
Cell Type: Simple Columnar Epithelial Cells
Function: Secrete alkaline mucus to protect stomach wall against acidic gastric juices
Stomach Cell Types 2: Gastric Glands
Cell Types:
- Mucous Neck Cells: Role not understood
-Parietal Cells: Secrete hydrochloric acid
-Chief Cells: Secrete fat-digesting enzymes called lipases
-Enteroendocrine Cells: Release chemical messages that aid in digestion
Stomach Gastric Secretion phases and what initiates them?
1.) Cephalic Phase: The taste, sight, smell or thought of food
2.) Gastric Phase: Food entering the stomach
3.) Intestinal phase: Food entering the duodenum
What does Bile do?
Produce enzymes that breaks down food
What do Pancreas do and the Pancreatic Juice elements and their function?
Pancreas: Secrete alkaline bicarbonate to balance hydrochloric acid produced in the stomach
Pancreatic Juice Elements and Function:
-Amylases: Breaks down carbs
-Lipases: Breaks down lipids (fats)
-Nucleases: Break down nucleic acids
-Proteases: Protein-digesting enzymes
Small Intestine Regions
-Mucosa
-Submucosa
-Muscularis Externa
-Serosa
Small Intestine Region (Mucosa)
Functions:
-Epithelium: Secretes mucus, digestive enzymes, hormones
-Lamina Propria: Contains capillaries for nourishment and absorption
-Muscularis Mucosa: Smooth muscles that produce movement of mucosa
Small Intestine Region (Submucosa)
Blood, Lymphatic vessels and follicles, Nerve fibres
Small Intestine Region (Muscularis Externa)
Segmentation and peristalsis of small intestine
Small Intestine Region (Serosa)
Protective Outermost Layer
Subdivisions of Small Intestine
-Duodenum
-Jejunum
-Ileum
What does Duodenum do in Small Intestine?
Receive bile from liver and pancreatic juices from pancreas
What does Jejunum do in Small Intestine?
Further digest fodder coming From stomach
What does Ileum do in Small Intestine?
Absorb nutrients from food so they can be used by the body
Enzymes of Digestion
Digestion: Catabolic
Function: Breakdown of large food molecules into monomers
Absorption: Moves substances from the lumen of the GI tract into the body. GI tract can only absorb Monosaccharides
Saliva Functions
-Cleanses mouth
-Moistens and dissolves food chemicals
-Contains enzymes that begin the breakdown of starch (amylase)
Types of Saliva
-Serous (Watery) Secretions
-Mucous (Thick/Vicious) Secretions
Types of Saliva: Serous (Watery) Secretions
-Helps in lubrication and digestion of carbs.
-Rich in water, electrolytes and enzymes (Salivary Amylase)
Types of Saliva: Mucous (Thick/Vicious) Secretions
Lubricates an protects surfaces from mechanical abrasion, chemical irritation and microbial invasion
