Digestive System Flashcards
What is the function of the digestive system?
Ingestion:Taking in of food to stomach
Mastication:Chewing food
Propulsion which consists of Deglutition which is swallowing and then Peralstalsis which is movement down the digestive system
Mixing-Which is movement in the small intestine
Secretion-lubrucating and liqifying
Digestion
Absorption-Move from tract to circulation or lymph
Elimination -Removal of food out the body
What is the vestibule in the oral cavity?
It is the space between cheeks or lips and avelolar processes
What is the structure of lingual frenelum?
At the base of the frenelum is a V shaped hump of tissue at the floor of the mouth
Where are Whatons ducts?
Whartons ducts are at the center just in front of the attachment of the frenelum which empty the sub maxillary and sub lingual glands
What are the 3 pairs of salivary glands?
The parotid
The submaxillary
Sublingual
What are the functions of the salivary glands?
Lubrication
Prevents bacterial infection
Produces salivary amalyse which breaks down starch
Produces saliva
What is the structure of the paritid gland?
Mainly consists of serous acini and produces alot of salivary amalyse and is drained mainly by Stensens ducts which empty at the vestibular at upper molar
Where is the sublingual gland located?
It is located at the inferior mucosa of the floor of the mouth and just anterior to the process submandibular gland
What is the function of the mucous acini in the sublingual gland?
ACTS as a buffer and lubricant
What does the submandibular duct secrete?
Mucins,salivary amylase,glycoprotiens and buffers
What is the composition of Saliva?
1.5 liters of Saliva are produced daily
99% Is water and the other 0.6% consists of glucoproteins,waste products,Na,Cl,HCO3
Mucins(Glycoproteins) which lubricate food making is easier for swallowing the food
Lyosozome kills bacteria
The Ptyalin(Salivary amylase which breaks down starch in the mouth but inactive in the stomach
Then we have Salivary lipase which begins fat digestion
What is control of Salivary secretion?
It’s part of the autonomic nervous system
It’s innervated by the parasympathetic and sympathetic nerves
The parasympathetic nerves originate in the salivary nuclei in the medulla oblongata and synapses at the submandibular and otic ganglia
And stimulated by receptors monitored by the trigeminal nerve and or taste buds innervated by the cranial nerve X,VII,XI
The parasympathetic stimulation speeds up secretion
What does irritation in the oesphagus,stomach and small intestine do?
It increases secretion
What are the other parts of the brain that affect secretion?
The stem nuclei and higher centers
What does sympathetic stimulation do?
It produces thick Saliva and inhibits secretion
What is the structure of the Pharynx?
Nasopharynx
Oropharynx
Larynagopharnx
What is the purpose of the Oesaphagus?
Transmits food from the phyrnx to the stomach
How is food transmitted to stomach?
The diaphragm has a oesopheagal hiatus which food passes through and then to the end of the stomach which is the hiatal hernia
What are the 3 phases of Deglutition?
Voluntary,Pharyngeal,Eosophygeal
What happens during the voluntary stages of Deglutition?
The bolus moves from the oral cavity to phyrnx
What happens during the Eesophegeal phase?
This is where the epiglottis is tipped posteriorly and the larynx is elevated and prevents food from passing through the larynx but rather into the pharynx
What is the pharyngeal phase?
This is where the upper sphincter relaxes and the pharynx relaxes and allows food to pass through the eosophagus
What is the purpose of the parietal cells in the stomach?
It produces hcl which kills microorganisms that enter digestive system and then converts inactive pepsinogin to pepsin
What are the chief cells?
They produce pepsinogen which is a protease enzyme
What do the lacteals do?
The recieve the lipoprotein before transporting them to the circulatory system
What do the muscular walls do?
They maintain the movement of chyme for peralstalsis
What are the two openings in the stomach?
The gastroesophegeal-Opening to the the oesphagus
Pyloric-To the duodenum
What are the layers of the stomach?
The serosa
The muscularis -outer longitudinal,middle circular and outer oblique
Submucosa
Mucosa
What ate rugae in the stomach?
It folds in when the stomach is empty
What are the divisions of the small intestine?
The duodenum
The jejunum
The illeum(Peyers patches or lymph nodes)
What is the site of the greatest absorption and digestion?
The small intestine
What are the digestive enzymes of the small intestine?
Disaccharidase-Breaks down disaccarides to monosacharides
Peptidase-Hydrolyizes peptide bonds
Nucleidase-Breaks down nucleic acids
How do the duodenal glands assist in secretions in the small intestine?
The duodenal glands are stimulated by the vagus nerve,secretin,chemical or irritation of the duodenal mucosa
What are the lobes of the liver?
The right,left,quadrate and caudate
What are the ducts at the liver?
Common Hepatic
Cystic from gallbladder
Common bile(which joins the pancreatic duct to the hepatopancreatic ampulla
What are functions of the liver?
Bile production-Salts emulsify fats and contains bilirubin
Nutrient interconvertion
Detoxification -Hepatocytes remove ammonia and convert it to urea
Phagocytosis-Where Kupffer cells remove worn out rbc and wbc and some bacteria
Storage-copper,iron and glycogen
Synthesis -Albumin,Heparin,clotting factors
What is the function of a gallbladder?
Bile is stored here and concentrated
And stimulated by Vegas stimulation and cholecytokinin
Abd bile Is dumped into small intestine
What are the components of the large intestine?
Cecal
Rectum
Canal
Rectum
What are the movements in the large intestine?
Mass movements after meals
Local reflexes in enteric plexus
Gastrolic and duodenocolic
Defecation reflex dissension of rectal wall by feaces
Defecation
What are the secretions of the large intestine ?
Parasympathetic stimulation increases production of goblet cells to secrete mucus
Pumps bicarbonate ions for chloride ions
Then sodium ions for hydrogen ions
