Gastrointestinal System: Structure & Function Flashcards
The Gastrointestinal System
A network of organs and
specialised cells that
enables you to transform the food you eat into the energy and nutrients required for life.
The Gastrointestinal Tract
Mouth
Oeophagus
Stomach
Small intestine
Large intestine
Anus
Accessory Organs
Salivary glands
Liver
Gallbladder
Pancreas
Mesentery
Membranous tissue
Surrounds organs of the GI tract
Holds intestines in place
Provides blood vessels and lymphatics
Mouth
Teeth
Tongue
Mucous membranes
Main function is to chew food
Pharynx andepiglottis
Prevent food travelling to the lungs
Oesophagus
Tube like structure
Involuntary movement of food bolus
Transports food bolus to stomach
Stomach
Mixing
Protein digestion
HCl, Pepsin
Fat emulsification
different section
esophagus
cardia
fundus
body
pylorus
pyloric sphincter
duodenum
Small Intestine
Longest part of the GItract
Main site of absorption
Divided into 3 sections
Crypts of Lieberkuhn
Paneth cells - defensins - antimicrobial - lysozymes - phagocytic
Stem cells – regeneration
Gobletcells - mucous
Large Intestine
water and ion conservation
bulk movement of faeces
storage
defaecation
Salivary Glands
Lubrication - mucus
Protection – thiocyanate, lysozymes
Digestion
Amylase
Lipase
Liver
Bile productionandexcretion
Gallbladder
Concentrating reservoir for bile
Delivers bile to the duodenum in response to meals.
Pancreas
Makes enzymes to digest proteins, fats,and carbohydrates
Produces the hormones insulin and glucagon
Functions of the Gastrointestinal System
ingestion
secretion
movement
digestion
absorption
excretion
Ingestion
Ingestion - the process of taking in food, or drink, through the mouth.
Secretion
Secretion – the release of substances that contribute to digestion.
Movement
Segmentation- contract and relax
Peristalsis- contract and puch froward
Digestion
Digestion - breakdown of food into smaller components that can be absorbed into the bloodstream.
- Mechanical digestion
- Chemical digestion
Mechanical Digestion
Physically breaking down food substances into smaller particles
mastication
peristaltic contractions
gastric acids
Chemical Digestion
Use of enzymes to breakdown food:
Fats → fatty acids and monoglycerides
Nucleic acids → nucleotides
Polysaccharides or carbohydrate sugars → monosaccharides
Proteins → amino acids
Secreted by accessory organs
Absorption
Absorption – the process through which nutrients, water and electrolytes enter the blood.
Excretion
Excretion- the process by which metabolic waste
is eliminated from the body
Summary
The GI system is important as it transforms the food you eat into theenergy and nutrientsrequired for life
The main organs of the GI system include the mouth, oesophagus, stomach, small intestine and large intestine
There are 6 main functions of the GI system: ingestion, secretion,movement, digestion, absorption, excretion and immune function
Ingestion occurs in the mouth
Movement occurs in the mouth, oesophagus, stomach, small intestine and large intestine
Digestion occurs in the mouth, stomach, small and largeintestine
Absorption occursin the small and large intestine
Excretiontakes place in the large intestine
The large intestine is involved in immune function
