Grand Tour of the Alimentary Canal Flashcards
What is the Four functions of the digestive system
Digestion
Secretion
Absorption
Motility
What is the function of the mouth
Break down food chemically (saliva) and mechanically (chewing)
What is the general functions of saliva
Gives lubrication allowing the ability to swallow and contains amylase to break down food for digestion
What is the function of the stomach
Digestion of proteins
Sterilisation
Reduce food to liquid form
Allows storage
Other than in saliva where do you find digestive enzymes for fats, proteins and carbohydrates
Pancreas
What is the purpose of the liver in the digestive system
Produces bile salts that emulsify the fats/lipids to aid digestion in small intestine
Filters product of digestion
Stores excess nutrients
Where is concentrated bile stored
Gal Bladder
Where does the final stage of chemical digestion occur
Small intesitne
What features of the small intestine allows for maximum absorption
Vast surface area due to the folds and the presence of micro vili
What is the functions of the large intestine
Water absorption
Bacteria fermentation
Formation of faeces
Name the four colons that form the large intestine
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
What part of the Large intestine goes to the rectum
Sigmoid colon
What is the name of three parts that make up the small intestine
Duodenum
Jejunum
ileum
How long is the alimentary canal
Mouth/Oesophagus to Rectum
= 8m
The alimentary canal has the same structural arrangement of what 4 distinct layers
Mucosa
Submucosa
Muscularis externia
Serosa/adventitia
What is the further divides of the mucosa layer
Epithelium
Lamina propia
Muscularis mucosae
Where in the digestive tract would the epithelium be stratified squamous
Mouth
Oesophagus
Anal canal
Why in the stomach, small and large intestine is the epithelium simple columnar
Adapting for function as allows greater absorption to rescued the absorption time
What is the functions of the epithelium
Forms barrier separating lumen of alimentary canal from body
Synthesis and secretion of digestive enzymes, hormones, mucus
Absorbs products of digestion
What is the lamina proper, and its function
a loose connective tissue layer (glands and lymph vessels) that supports the epithelium
What is the submucosa and it function
Thick irregular connective tissue that
Supports the mucosa
What is contained in the submucosa layer
Neurons
Blood vessel
Lymph vessel
Glands
What is the name of the neutrons extensive network found between the Submucosa layer and the muscular layer and what is its autonomic intervention
Messiners plexus
parasympathetic
Where are submucosa glands found and what do they produce
Oesophagus - Mucus
Duodenum Glands (brunners gland) - Bicarbonate
What is the purpose of the secretion of bicarbonate
Neutralsies the acid produced from digestion
What is the name of the connective tissue layer found outside the alimentary canal
(in reference to peritoneal cavity)
Inside peritoneal cavity - serosa
Outside peritoneal cavity - adventitia
What is the two concenteric thick layers of smooth muscle found in the muscular externa
Inner layer = Circular muscle
Outer layer = longitudinal layer
What is the purpose of circular muscle
Constricts lumen
What is the purpose of the Longitudinal muscle
Shortens the tube
What is the overall function of the muscularis externia layer
Giver overall motility by Peristalsis and segmentation
What is the name of the neutron plexus found in-between the two muscle layers and what is the autonomic innervation
Myenteric plexus
Both sympathetic and parasympathetic
What forms the enteric nervous system
The myenteric plexus and the submucosa (messier) plexus
What makes up the autonomic control in the digestive system
Long (parasympathetic) and short (Enteric nervous system) reflexes
What nerve gives parasympathetic autonomic intervention
Vagus nerve
What nerve gives sympathetic autonomic intervention
splanchnic nerve
What nerve stimulates secretion and motility in the digestive tract
Vagus nerve
REST AND DIGEST WITH THE PARASYMPATHETIC
(splanchnic = inhibitory)
How does the innervation of the salivary gland differ
Isn’t innervated by vagus nerve
Stimulated by the facial nerve and the glossopharyngela nerve
also stimulated by the splanchnic rather than being inhibited
What are the three branching arteries of the descending abdominal aorta
Celiac trunk
Superior and inferior mesenteric artery
What does the celiac trunk supply
Stomach
Small intestine
Pancreas
Liver
What drains into the superior mesenteric vein and is suppled by the superior mesenteric artery supply
Small intestine
Caecum
Ascending colon
Transverse colon
What does the inferior mesenteric artery supply and what drains into the inferior mesenteric vein
Descending colon
Sigmoid colon
Rectum
Where does all veins drain into in the alimentary canal
Hepatic portal vein
What does the stomach drain into
Gastric vein
What does the Pancreas drain into
Splenic vein
What does the hepatic vein drain into
Inferior vena cava
What is the hepatic portal vein rich in
Nutrients
not oxygen
What is the hepatic artery rich in
Oxygen
not nutrients
What is present in the hepatic vein
Oxygen and nutrients