Digestive system

What are the 7 primary organs of the digestive system?

Mouth

Pharynx

Oesophagus

Stomach

Small intestine

Large intestine

Rectum and Anal canal

What are the 4 accessory organs of the digestive system?

Three pairs of salivary glands

Pancreas

Liver

Biliary tract

What is the peritoneum?

Serous membrane forming a closed sac within the abdominal cavity

What are the two layers of the peritoneum?

Parietal

Visceral

What is the function of the peritoneal fluid?

Prevent friction between organs in close contact

What are intraperitoneal organs?

Organs completely by visceral peritoneum

What are retroperitoneal organs?

Organ covered by visceral peritoneum anteriorly

What is the mesentery?

Double fold in the peritoneum suspending the small and large intestine from the abdominal wall

What is the greater omentum?

Fused double fold of the peritoneum which attaches to the stomach and transverse colon

What are the two functions of the greater omentum?

insulation and energy storage

What are the four layers of the alimentary canal?

Adventitia/serosa

Smooth muscle

Submucosa

Mucosa

What is the adventitia?

Outermost layer of tissue at the superior region of the oesophagus

What is the serosa?

Outermost layer of tissue at the distal part of the oesophagus

What is the structure of the muscle layer?

Outer layer of longitudinal smooth muscle

Inner layer of circular smooth muscle

What are the two oesophageal sphincters?

Upper sphincter preventing airflow

Lower sphincter preventing reflux

What is the function of the muscle layer of the alimentary canal?

Involuntary contraction and relaxation occuring in waves pushing the content forward

What is the submucosa made up of?

Loose aerolar connective tissue of collagen and elastic fibres

What are the three layers of the mucosa?

Mucous membrane

Loose connective tissue

Smooth muscle

What are the cells of the mucous membrane?

Protective stratified squamous epithelium with mucus secreting glands

What are the two functions of the mucous membrane?

Lubricates the wall of the tract

Provides a physical barrier

What is the structure of the lining of the mouth?

Mucous membrane containing small mucus secreting glands

What is the vestibule?

Anatomy between gums and cheeks

What is the uvula?

Curved fold of muscle covered in mucous membrane

What are the cells that make up the tongue?

Stratified squamous epithelium with numerous papillae

What are salivary glands?

Exocrine glands that release salvia into ducts

What are the three pairs of salivary glands?

Parotid Glands

Sublingual glands

Submandibular glands

Where do the parotid gland ducts empty into the mouth?

Second upper molar

Where do the submandibular glands empty into the mouth to?

One on each side of the frenulum

What is the structure of the salivary glands?

Lobules of acini lined with secretory cells surrounded by a fibrous capsule

What are the three layers of the pharynx?

Mucosa

Connective tissue

Involuntary muscles

What is the location of the oesophagus?

Runs centrally behind the trachea and heart

What is the structure of the oesophagus when it reaches the stomach?

Passes between diaphragm muscle fibres at T10

Curves upwards to enter stomach to prevent gastric reflux

What are the two structures anterior to the stomach?

Left lobe of liver

Anterior abdominal wall

What are the five structures anterior to the stomach?

Abdominal aorta

Pancreas

Spleen

Left kidney

Adrenal gland

What are the three superior structures to the stomach?

Diaphragm

Oesophagus

Left lobe of liver

What are the two inferior structures to the stomach?

Transverse colon

Small intestine

What are the two left lateral structures to the stomach?

Diaphragm

Spleen

What are the two right lateral structures to the stomach?

Liver

Duodenum

What are the three regions the stomach occupies?

Epigastric

Umbilical

Left hypochondriac

What are the two structures the stomach is continuous with and which structures join them?

Oesophagus at the lower oesophageal sphincter

Duodenum at the pyloric sphincter

What are the two curvatures of the stomach?

Lesser

Greater

What are the three regions of the stomach?

Fundus

Body

Pylorus

What are the differences in the muscle layer of the stomach?

Additional inner layer of oblique muscle fibres

What are the rugae and what are its features?

Longitudinal folds in the stomachs mucous membrane lining

Stretch out when the stomach fills

What is the function of the gastric smooth muscles and what is it for?

Contraction to break down food and mix it with gastric juices to make chyme

What are peristaltic waves in the stomach?

Waves of contraction to propel the chyme towards the pylorus

What is the function of the pyloric sphincter that aids proper digestion?

Remains closed to retain food until it is sufficiently mixed

What are the two regions the pancreas occupies?

Epigastric

Left hypochondriac

What are three sections of the pancreas?

Head

Body

Tail

What are the features of the pancreas that make it an exocrine structure?

Made up of multiple lobules of acini

Each acini duct unites to from the pancreatic duct

What are the features of the pancreas that make it an endocrine structure?

pancreatic islets secrete hormones directly into capillaries

What are the three regions the liver occupies?

Right hypochondriac

Epigastric

Left hypochondriac

What are the four lobes of the liver?

Right lobe

Left lobe

Caudate lobe

Quadratus lobe

What is the structure of the external anatomy of the liver?

Thin inelastic capsule

What is the coronary ligament?

Folds attaching the liver to the diaphragm

Form right and left triangular ligaments

What is the function of the falciform ligament?

Divides the lobes of the liver

What are the six ducts of the biliary tract?

Right hepatic

Left hepatic

Common hepatic

Cystic

Common bile

Pancreatic

What are the three additional structures of the biliary tract?

Hepatopancreatic ampulla of the vater

Duodenal papilla

Hepatopancreatic sphincter

What are the modifications to the structure of the walls of the bile ducts?

Mucous membrane has circular folds to act as a spiral valve

What is the pathway of bile through the biliary tract?

Cystic duct

Common bule duct

Duodenum through ampulla of vater

What is the structure of the gall bladder?

Same as alimentary canal

Includes oblique smooth muscle layer

Superiorly contact with liver

Inferiorly covered by peritoneum

What two organs is the small intestine continuous with and what structures join them?

Stomach by the pyloric sphincter

Large intestine by the ileocecal valve

What is the function of the small intestine?

Chemical digestion

Absorption of most nutrients

What are the three sections of the small intestine?

Duodenum

Jejunum

Ileum

What are the modifications of the small intestine walls?

Permanent circular folds called plicae in the mucosa that promote mixing of chyme

What is the caecum?

First part of the large intestine that merges with the ascending colon

What is the function of the ileocecal valve?

Connects the terminal ileum to the large intestine

What are the four continuous parts of the large intestines?

Ascending colon

Transverse colon

Descending colon

Sigmoid colon

What are the two flexures of the large intestines?

Hepatic flexure

Splenic flexure

What is the rectum?

Slightly dilated section of large intestine linking the sigmoid colon to the anal canal

What is the structure of the anal canal?

Two muscular sphincters made up of thickened circular muscle rings

What are the two muscular sphincters of the anal canal?

Internal

External

What are the modifications of the longitudinal muscle fibres in the caecum and colon?

Form three strips called taeniae coil instead of a layer

Slightly shorter than anal canal