Chapter 6 - digestive system Flashcards
Active transport
Use of energy to move substances, usually ions across a cell membrane
Bile
- where from
- what does it do
Secretion of the liver, stored in the gallbladder and released into the small intestine. Contains bile salts that mechanically digest fats through the process of emulsification.
Bile salts
Bile is made up of bile salts. Substances that break fats into tiny droplets (emulsifies salts)
Bolus
A ball like structure of food and saliva
Chemical digestion
Breakdown of food to small molecules by chemicals
Chyme
Semifluid mass of partially digested food that leaves the stomach
Circular muscle
Smooth muscle with fibres arranged in a circle around an organ like the stomach
Deoxyribonuclease
An enzyme in pancreatic juice that digests DNA
Digestion
Mechanical and chemical breakdown of food to small molecules that can be absorbed into the body
Digestive system role
breaks down the food taken into the body into smaller components ready for absorption into the cells
Emulsify
Process of breaking down large fat globules into smaller droplets toenable them to mix with the enzymes.
The SA of the fat increases making it easier for digestive enzymes to access and break down the fat molecules.
Elimination - digestive system
Removal from the body - removal of indigestible material from the body. Use the term elimation when describing the removal of faeces.
Faeces
Material passed out of the rectum. Composed of undigested matter
Gastric juice
- composed of
The digestive juice secreted by the glands of the stomach.
- HCl
- Gastric protease
- Mucus
Ingestion
Intake of food and liquids into the mouth
intestinal juice
- what does it digest
- contains enzymes
Digestive juice secreted by the glands of the small intestine. Complete the digestion of fats, carbohydrates and proteins.
- Amylase
- Peptidase
- Lipase
Lacteal
Lymph capillary in villus diagram in the small intestine that absorbs fat from digested food
Large intestine
Part of the intestine between the small intestine and the anus. Made up of the caecum, colon and rectum. Undergoes peristalsis contractions to move food along the intestinal tract. Where much of the remaining water is absorbed from the remaining compound.
Longitudinal muscle
Smooth muscle with fibres arranged lengthwise along an organ.
Mastication - process
Process of chewing to grind or crush food with the teeth
Mechanical digestion
- example
Mechanical breakdown of food into smaller particles. Stomach churns particles, segmentation in small intestine, teeth grind food
Microvilli
Microscopic projections from the membranes of cells living the small intestine. They increase the surface area for absorption.
Mucosa membrane
Internal surface of the entire digestive system. Protective barrier against enzymes.
Oesophagus
Tube that carries food from the throat to the stomach
Pancreatic amylase
Enzyme in pancreatic juice that breaks down starches - to disaccharides
Pancreatic juice
Liquid secreted by the pancreas that is full of digestive enzymes. Aids in digestion in the small intestine.
Pancreatic lipase
Enzyme in pancreatic juice that breaks down fats - fatty acids and glycerol
Pancreatic protease
Enzyme in pancreatic juice that breaks down proteins - peptides
Peristalsis
Waves of muscular contraction that push food along the alimentary canal. In oesopghas and small intestines and large intestine. Move ingested materials through the digestive tract.
Pharynx
The throat. Joins the mouth cavity to the oesophagus and the trachea
Pyloric sphincter
Ring of smooth muscle between the stomach and the duodenum.
Ribonuclease
Enzyme in pancreatic juice that digests RNA
Saliva
Fluid secreted into the mouth by salivary glands to begin the digestion of food (chemical)
Segmentation
Mechanical digestion process occurring in the small intestine which uses the contraction of circular muscles to push the chyme into segments, mixing it with digestive juices
Small intestine
- size
- receives
- absorption maximised by
- M and C
Longest part of the alimentary canal, receives material from the stomach. Internal surface is lined with villi and microvilli to increase SA for absorption.
C - pancreatic juice and intestinal juice
M - Bile and segmentation
Stomach - what it does to the material
Muscular organ that receives food from the esophagus and mixes it with acid and enzymes to form chyme
Villi
Finger like projections from the internal lining of the small intestine. Enodethlial cells covering the outside of the villi have microscopic projections called microvili
chemical digestion
- carbohydrates
- proteins
- lipids
- glucose
- amino acids
- fatty acids and glycerol
HCl in gastric juice
Acidic environment kills bacteria and activates gastric protease
Mucus in gastric juice
Protects the lining of the stomach as of the acidic environment from the HCl in gastric juice
Gastric protease enzyme in gastric juice
Begins the digestion of proteins in the stomach when activated by HCl
duodenum
first part of the small intestine. where gastric protease in the chyme from the stomach become inactive from the more neutral environment that is created by the bile and other juices secreted into the small intestine.
Intestinal amylase
Disaccharides to glucose
Intestinal peptidase
Peptides to amino acids
Intestinal lipase
Converts lipids to fatty acids and glycerol
6 basic activities of digestion system performed
- ingestion of food
- mechanical break.
- chemical break.
- movement along alimentary canal
- absorption
- elimination
M and C digestion in mouth cavity
M - teeth
C - saliva containing salivary amylase
Salivary glands
Produces saliva which contains mucus to lubricate the mouth and enzyme salivary amylase that begins the breakdown of starch
Cardiac sphincter
- regulates
- prevents
Regulates passageway of food and liquids from the oesophagus into the stomach.
Prevents the acidic contents of the stomach regurgitating back into the oesophagus.
M and C in the stomach
M - churning action breaks down bolus
C - when gastric protease is activated by HCl, begins breakdown of proteins
Pyloric sphincter
Muscular ring between stomach and small intestine. Controls movement of chyme from the stomach into the duodenum to ensure it is released in small manageable amounts for proper digestion.
Large intestine
- made of
- absorbs
No villi and no digestive juices secreted but the lining does secrete large amounts of mucus.
Where the remaining water from faeces and important vitamins made by bacteria that act on remaining compound are absorbed.
Structure located at the junction between small and large intestine
Caecum
Attached to caecum.
Appendix. Role in immunity and storing useful bacteria.
Colon
- size
- movement
Longest part of large intestine, very slow movement of materials through peristalsis allows for water reabsorption.
Rectum
Final part of L.I where faeces are formed and stored before elimination.
Alimentary canal plays role in digestion
Each part of alimentary canal has specialized structures and functions that contribute to the overall process of digestion and nutrient absorption.
Accessory organs in the digestive system
Assist in digestive process but are not part of the digestive tract itself. pancreas, gall bladder, liver etc
