Flashcards
Digestive Sytem
Cards in this deck (69)
- 1Name and identify the organs that make up the Digestive Tract *--
- 2*Describe the basic functions of the digestive tract, mechanical and chemical digestion*--
- 3*Define the process of secretion, absorption and elimination of wastes*--
- 4*Identify the accessory organs and their functions*--
- 5What is the Digestive System made up of?The digestive system is made up of the GI tract and accessory organs that assist the GI tract
- 6What is the Gartointestinal tract madeup of?Oral cavity
Oesophagus
Stomach
Small intestine
Large Intestine
Rectum
Anus - 7What are the accessory organs viscera?Liver
Gall bladder
Pancreas
Biliary Apparatus - 8What are the main functions of the Digestive System?Ingestion - the introduciton of solid and liquid materials into the oral cavity
Digestion - breakdown of large food items into smaller pieces and molecules
Propulsion - Action os moving the food material along the gastro-intertinal tract (GI) 2 types of movemet (Segmentation and peristalisis)
Secretion - Production and release of mucin, or fluids e.g. acid and bile
Absorption - passive or active transport of particles such as digestion products and water accross GI tract and into blood and lymph vessels
Elimination - Removal of undigestible materials in the form of feces - 9What epithelia lines the oral cavity?Stratified squamous epithelial cells
- 10What is teh entrance to the GI tract?Oral Cavity
- 11What occurs in the oral cavity?It is the first site of mechanical and chemical (enzymes in saliva digestion)
- 12What are the main two cavities of the oral cavity?Vestibule and Oral Cavity Proper
- 13What makes up the oral cavity?Hard Palate - roof of the oral caivty (Separates the oral cavity from the nasal caity)
Soft Palate - comprised mainly of skeletal muscle and ends in the Uvula
Uvula - and soft palate elevate to close of the nasopharynx
Tongue - manipulates ingested food
Tonsils - detects antigens that maybe present on food and drink and can elicit an immune response
Gingivae - Gums
Slivary glands - produce saliva and enzymes e.g. amylase - 14What are the phases of the oral cavity?VOLUNTARY PHASE - Food and Saliva mix in the oral cavity and form a bolus (Chewed up food). THis is manipulated by the tongue and pushed up agains the hard palate which directs the food posteriorly with its transverse folds towards the oropharynx.
PHARYNGEAL PAHSE (involuntary) - Tactile sensory receptors generate the swallowing reflex - controlled by the medulla oblongata. - The bolus travels quickly and involuntarily into the oesophagus - Soft palate and uvula elevate (block passageway between nasopharynx and oropharynx), bolus enters ororopharynx and then the larynx and laryngeal opening elevate towards the epglottis (covers and seal the glottis) = prevents food from entering the trachea.
OESOPHAGEAL PAHSE (involuntary) - Bolus goes into the stomach. - Superios oesophageal sphincter relaxes = allows food inot the esophagus where peristaltic waves push the food toward the stomach. Soft palate, uvula and larynx return to their original state. - 15What is the purpose of teeth?They are the initial site for mechanical breakdown of food via mastication
- 16What is the difference between child and adult teeth?Babies have 20 deciduous teeth (milk teeth) which generally erupt between 6 - 30 months after birth. THese teeth are eventually lost and replaces with 32 permanent teeth.
- 17What are the different salivary glands?Saliva is produced by 3 different paired glands:
PAROTID GLAND: Largest Gland and produces 25-30% of the saliva and is located just inferior to the ear which is connected through the parotid duct ot the oral cavity.
SUBMANDIBULAR GLAND: Produce 60-70% of the saliva and is located inferior to the body of the mandible.
SUBLINGUAL GLAND: Tiny glands that produce 3-5% of the saliva and located inferior to tongue and internal to the oral cavity - 18What is saliva?Consists of 99.5% water and 0.5% solutes (Ions, ImmunoglobulinA, Iysozyme, mucin and salivary amylase).
Around 1-1.5L of saliva is porduces daily
pH 6.4 (slightly acidic) - 19What is the function of the Salivary Glands?1. Moisten, cleans and lubricates
2. Chemical digestion - Amylase
3. Inhibit bacterial growth - Lysozyme
4. Allows food molecules to dissolve - Taste receptors - 20Types of muscles found in Tongue?BOTH SKELETAL MUSCLE
Intrinsic + within the body of the tongue
Extrinsic = run between the mandible and hyoid bone) - 21What is the purpose of the tongue and its muscles?To allow the manipulation and formation of the bolus
Papillae - come contain taste buds - 22What is the function of the oesphagus?The oesophagus allows us to swallow (deglutition) our food.
- 23How does the oesophagus work?Involves over 22 separate muscle groups
Pharyngeal-esophageal phase - controlled by the brain stem (medulla and lower pons)
Once food enters teh pharynx respiration is momentarily inhibited
Larynx rises so that the epiglottis covers teh trachea whilst the upper oesphageal sphincter relaxes
Wave like peristaltic contractions create pressure waves that propel the food through the pharynx into the oesophagus.
Sold food then apsses fromthe oropharynx to the stomach when the gastroesophageal sphincter relaxes.
Oeoshagus passes through the diaphragm at the oesphageal hiatus (Thoracic 10) - 24How can the oesophagus be identified in a cadaver?--
- 25How is food moved through the oesophagus?Assisted by gravty, perystalsis occus to move the bolus through the oesophagus.
Peristalsis = coordinated contraction and relaxation of the musculature in the GI tract wall
Peristalsis typically involves alternate contraction of lingitudinal and circular muscle coats (the former expanding the lumen of a bolus, the latter contstricting the lumen behind it) - 26What are the features of the abdominal cavity?Perietal Peritonium - Serous sac that lines the abdominal cavity
Visceral Peritoneum - covers most of the viscera (lines the organs)
Retroperitoneal organs - fixed organs stuck to the wall - external or posterior to the peritoneum
Intraperitoneal organs - re free - lcoation os the organ or structure that si completely covered in visceral peritoneum - 27What digestive organs are retroperitoneal and what organs are intraperitoneal?Intra- Stomach, Transverse colon, Jejunum and Ilium, Sigmoid Colon
Retro - Duodenum, Ascending colon, Descending colon, Rectum - 28What is the Mesentary and what is its role?The mesentary consists of two sheets o serous membrance with loose connective tissue. The sheets of serous membrane of the mesentary become continuous with the parietal layer of serous membrane at the parietal attachment of the mesentery (adjacent to the body wall).
Mesentery proper is a large, fan-shaped, double layered fold of peritoneum that connects the jejunum and ileum to the posterior abdominal wall. Between the layers is fat, arteries, veins, berves and lymphatics so they are also important for the transport of vessels.
Organs within a mesentery are mobile.
Its two major roles are:
1. Provides an attachement enabling mobility.
2. Vessels and nerves are transmitted in the connective tissue between the two sheets or serous membrane forming the mesentary - 29What is the greater omentum?Like an apron - attaches to teh greater curvature of the stomach and the first part of the duodenum. It drapes down and ascends past superior surfae of the transverse colon and loops back round to attach to the posterior abdominal wall.
- 30What is the lesser omentum?Lesser omentum extends from the lesser curvature of the stomach and first part of the duodenum and passes inferior on the liver.
- 31What are the regions of the stomach?CARDIA = Small narrow entry into the stomach lumen from the oesophagus.
FUNDUS = Superior surface contacts the diaphragm
BODY = Largest region
PYLORUS = Terminal region of the stomach
- PYLORIC ORIFICE = opening with teh duodenum
- PYLORIC SPHINCTER - regulare the entrace of the chyme into the small intestine - 32What is the main fucntion fo the Stomach?THe stomach is located in the left upper quadrant of the abdomen immediately inferior to the diaphragm
Performs further mechanical and chemical digestion fo the bolus. After processing in the stomach teh bolus is known as CHYME.
The stomach contracts its thick muscularis layer, that churns and mixes the bolus along with gastric secretions.
Chemical breakdown of the bolus is performed by the gastric juices and enzymes that are secreted. - 33What are the gastric folds in the stomach, and what are their purpose?The gastric folds are called RUGAE
And are found only when the stomach is empty as they allow the stomach to expand - 34What regions make up the small intestine?Duodenum - First Segment (10 inches)
Jejunum - Middle segment (2.5 m)
Ileum - Last segment (3.6 m) - 35How are material moved through the gut?Peristalsis and Segmentation move materials through the gut.
Peristalisis =
Segmentation = - 36Main Components of the Dunodenum?-Originate at he pyloric sphincter, its C-shaped abd joins continuously with the jejunum at the duodenojejunal flexure
- Most of this segment is retro peritoneal, the very proximal part is intraperitonean and connects to the liver via the lesser omentum.
- Within the duodenum is the major duodenal pailla - where bile and pancreatic juices enter.
- THe minor duodenal papilla receives a small amount of pancreatic juice via an accessory pancreatic duct. - 37Main components of the Jejunum?It is the main region for chemical digection and nutrient absorption.
It is intraperitoneal and suspended in the mesentery proper.
Often empty
Larger diameter and thicker wall than ilium
Site wehre most nutrients are absorbed
Large and prominent plicae circulares
Less prominant arterial arcade and longer vasa recta than ilium - 38Main components of the Ileum?Its distal end terminated at the ileocecal valve into the large intestine where another sphincter is located
It is intraperitoneal and suspended by the mesentery proper.
Small plicare ciculares, absent at terminal end
Large number of lymphoid tissue
More prominent arterial arcade and shorter vases recta than jejunum.
REMOVES BILE SALTS AND RECYCLES THEM BACK TO LIVER - 39What are the main regions of the Large Intestine?Cecum = Fist part of large intestine
Illeum opens into it, a the ilieocecal valve
Appendix opens onto it, inferior to the ileocecal juction
Colon = 4 PARTS
Asending Colon - retroperitoneal,
Transverse Colon - Intraperitoneal
Descending Colon - retroperitoneal
Sigmoid Colon - intraperitoneal
Rectum = retroperitoneal, 3 transerves folds - known as rectal valves. THese ensure that the fecal material is retained during the passing of gas.
Anal Canal = Passes through an opening in the levator ani muscles of the pelvic floor and terminates at the anus.
The anal canal has thin longitudinal ridges knwon as anal sinuses, teh cells that makwe up the sinuses secret muscus when they have pressure excerted on them.
The excess mucin lubricated the anal canal during defecation.
At the end of the canal are the internal (involuntary) and external (voluntary) sphincters. - 40Features of the appendix?Position of the appendix can vary
Narrow, WORM-LIKE blind tube
Has its own mesentary - mobile - 41What is the main function of the large intestine?Absorb most of the water ions and a small amount of nutriend from the remaining digestive material - the mateiral becomes harder and solidifies = feces
Stored the feces until the body is ready to defecate - 42Properties of the liver?--
Produces bile continuously. - 43What is the purpose of the biliary apparatus?Bile passes fromthe liver via the bilary ducts right and left hepatic ducts, that join to t form the common hepatic duct which then unites with the cystic dcut to form the (common) bile duct.
- 44What is the purpose of the Gallbladder?The liver produces bile continuouslt, however between meals the bile is stored in the gall bladder. When food enters the duodenum the gallbladder real eases the concetrated bile ino the duodenum throguh the major duodenal pailla.
Function:
- Stored Bile
- Concentrates Bile
- Releases bile in reponse to teh introduction of fatty food into the duodenum - 45What is the purpose of the pancreas?Retroperitoneal - lies transverselt posterior to the stomach across the post abdominal wall
Function:
- Produces pancreatic juice that enters the duodenum wia the pancreatic duct
- Pancreatic duct starts at tail and receives tributaies
- Usually unites with bile duxt to form hepatopancreatic ampulla that oens on the duodenum
Excocrine
- Secretion of digestive enzymes and bicarbonate (pancreatic juices)
Endocrine
- Secretion of hormone
- Insulin and glucagon
- Somatostatin - 46What is the purpose of the spleen?Connected to teh greater curvature of stomach and left kidney
Contain large amount of blood
Function:
- Primarily involved in identifying, removing and destroying expended erthrocyted and platelets and recycling iron and globin.
- Stored erythrocyted, platelets
Prenatally, the spleen is a hematopoietic organ - 47What are the main accesory organs and their functions in the digestive system?Liver = bile production, detox, store excess vitamins, syntesize blood plasma, breakdown and recycle components of RBCs
Pancreas = Endocrine/exocrine
Gall bladder = stores and concentrates bile
Biliary apparatus = carry bile from liver and gall bladder to duodenum - 48What arteries support what sections of the digestive system?All branch from the Aorta
Celia Trunk = Supplies all foregut structures
Superior mesenteric artery = Supplies all midgut structures
Inferior mesenteric atery = Supplies all hindgut structures - 49How does venous drainage occur from the Digestive System?Venous drainage of the spleen, pancreas, gallbladder and abdominal part of the GI tract.
The veins merge into the Hepatic Portal vein.
Nutrients move into the veins (Superior mesenteric vein and inferior mesenteric vein) through either passive diffusion or active transport. The nutrient rich deoxygenated blood then flows into the hepatic portal vein, which connects to the liver (after splitting into left and right for the different lobes). The blood has any toxins removes and then the blood flows into the hepatic vein which joins to the vena cava and moves onto the heart. - 50What epithelia makes up the taste bud and tongue?Keratinized squamous epithelia
- 51What epithelia? And where would this be found?Taste Bud and Tongue
Keratinized Squamous Epithelium - 52WHat epitherlia makes up the salivary glands?Simple columnar epithelium
Salivary Glands - 53What is the epithelia? And where would it be located?Simple Columnar Elithelium
Salivary Glands - Good for secretion?
- 54What are is the histology from the oesophagus to the large intestine (Everything aside from stomach)? MAJORITY ALL SIMPLE COLUMNAR
- 55What epithelia is located in the mocusa?Oesophagus and Anal Canal - Stratifies squamous epithelium
Stomach - Secretory epithelium showing surface pits and long gastric glands secreting gastric galnds
Small Intestine - Absorptive epithelium showing villi (Staining shows microvilli - PAS staining attaches to glycoproteins that cover membranes)
Large Intestine - Absorptive epitherlium modified to extract water - 56What Epithelium? And where would it be found?Stratified Squamous Epithelium
Would be found in Oesophagus and Anal Canal
- 57What Epithelium? And where would it be found?Simple Columnar Epithelia
Secretory eptiherlium showing surface pits and long gastric glands secreting gastric glands.
FOund in Stomach
- 58What Epithelium? And where would it be found?Simple Columnar Epithelia
Absorptive Epithelium showing villi (Staining shows microvilli - PAS staining attaches to glycoproteins that cover membranes)
Would be found in Small Intestine
- 59What Epithelium? And where would it be found?Simple Columnar Eptihelia
Golblet Cells (Lubrication etc)
Absorptive epithelium modified to extract water
Would be found in Large Intestine
- 60What are the three muscularis external layers of the stomach?3 smooth muscle layers
1. longitudinal
2. Circular
3. Oblique - 61Different cell types of stomach? IMPORTANTSurface mucousa cell =
Mucous neck cells = excrete acidic mucous to protect stomach
Parietal Cell = secretes hydrochloric acid and intrinsic factor
Chief cells = secrete pepsinogen - helps to break down food
Enteroendocrine cells = secreted gastrin - hormone - 62What are the features of the small intestine?Circular folds (Plicae circulares) =
Villi = increase surface area for bsorption
Microvilli = increase surface area for absorption
Intestinal Glands =
Submicosal Glands =
Brunner Glands = - 63Cells of the small intestine?Enteroendocrine cells = secrete hormone
Simple Coloumnar Epithelium - 64Features of the Duodenum histologically?Brunners Glnads = secretes alkaline fluid - to neutralise the contents that come from the stomach
Epithelia lines and the brunners sit within - 65INSERT HISTOLOGICAL IMAGE OF BRUNNERS GALNDS--
- 66Jejunum features?Plicae circulares = increasing surcare area
Plicae circulae - on top is Villi - on top is micro villi = which builds up a large surface area - 67HISTOLOGICAL IMAGE OF JEJUNUM--
- 68Cells of JejunumEnteroendocrine Cells - secrete hormone
Paneth Cells - antimicrobial
Goblet Cells - mucous
Simple Columnar Epithelial - 69Features of Large Intestine?Intestinal Glands =
Lymphatic Nodules =
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- Flashcards on Digestive Sytem, created by Elise Rawlinson on 01/04/2018.
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