Alimentation

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  • Created by: Sarah
  • Created on: 04-05-17 11:14
what controls entry into oesophagsus?
upper sphincter
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what is the function of the GI tract?
breakdown and absorption of nutrients
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how does the GI tract acheive this function?
1) mechanical-chewing 2)chemical- enzymes
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what is the diamter and how long is the oesophagus?
25cm long, 2cm diamter
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where does the oesophagus carry food to and from?
pharynx to stomach
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what structural feature of the the small intestine makes it adapted to absorbing food?
hgihly coiled/folded
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what makes up the small intestine?
duodenum, jejenum, ilium
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where does food that leaves the stomach go?
duodenum
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what part of the ANS stimulates digestion?
parasympathetic system
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what is peristalsis?
involuntary constircition and relaxation of muscles in small intestine or other pushing food along
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what does the mouth make food into?
a soft bolus
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what is saliva for?
digestion, lubritication,swallowing/speech, taste, antimicrobial function
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what is different about the GI tract from other organs?
it is part of the outside world
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what is part of the upper Gi TRACT?
Buccal cavity, oropharynx/oesophagus, stomach and duodenum
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what is part of the lower GI tract?
caectum, rectum and anal canal
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what does the caecum do?
absorbs fluids and salts remaining after interstininal digestion, mixes with mucus
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what happens in the rectum?
the faces is thickened by electrolytes and water being reabsorbed. Mucus added.
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functions of buccal cavity?
Mastication
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what is mastication
(teeth+tonugue mechanically break down food+ add saliva
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why do some people have more amylase than others?
amount you have is genetic
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what are the muscles of mastication?
masseter, temporalis and pteygoids
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what are the muscle sof mastication innervated by?
V3 of trigeminal (cnv)
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Where does digestion begin?
in the mouth
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what does saliva contain?
alpha amylase
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what does alpha amylase do?
breaks down starches in bolus
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what is the oesophagus?
a fibromuscular tube
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where is the oesophagus loctaed?
posterior of trachea and heart, pushes up against diaphragm
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where does the oesophagus enter the stomach?
the fundus
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what does the oesophagus consist of?
layersof muscle, CT, mucosa and submucosa
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what do the muscular layers of the oesophagus do?
perfoms peristaltic (contraction+relaxation) movements to push soft bolus into stomach
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where does the stomach lie in the body?
the upper left of abdominal cavity against the diaphragm
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what does Hcl do to bacteria?
doesnt kill it stops it proliferating
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what does the stomach secrete?
Hcl and proteases
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how long does it take the stomch churning through peristalisis to produce chyme?
40-60 minutes
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what is relased into the duodenum?
small amounts of chyme at a time
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what does the stomach do?
churn food, bag like can hold and store 1L of food, breakdown by proteases+Hcl
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what happens in the duodenum?
enzyme activity to break down chyme
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what does the duodenum regulate?
how much food is released by the stomach sends signals to hypothalmus saying this is too much
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what hormones does the duodenum use to reguklate control of stomach emptying?
cholecytostokinin and secretin
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where does much of the absorption occur in the small intestine?
jejenum
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what does the jejunum contain to maximise reabsorption?
villi epithelium that has microvilli
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what do they call the villi epithelium + microvilli of the jejunum?
brush border
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what is the PH of the jejunum?
PH 7
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what nutrient transport across epithelial cells requires AT?
amino acids, small peptides, vitamins, most glucose
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what is passive transport across epithelial cells
fructose
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whats the differences between the jejunum and Ileum?
ileum is smaller diamter of lumen and thinner walls, more fat in mesentry of ileum
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what does ileum have that is linked to the immune system and are encapsulated lymphoid nodules?
Peyers Patches
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what does the ileum absorb?
vitamin B12, bile salts and digestion products not absorbed by the jejunum
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what is another name for the large intestine?
colon
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3 functions of the large intestine?
1) absorb remaining water+Electrolytes 2) accepts and stores food remains that were not digested in the small intestine 3) eliminates solid waste from the body
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order of the large intestine?
appendix comes of cecum-> cecum -> ascending colon -> transverse colon -> descwending colon -> sigmoid colon -> rectum ->anus
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what is the structure of the Caecum?
a pouch like structure that is considered to be the start of the large intestine
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what valve does the chyme go through from the ileum to the caecum?
the ileo caecal valve
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start of the large intestine?
Caceum
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what is larger in herbivores where cellulose digesting bacteria are housed?
caecum
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what is smaller or not present in carnivorous animals an replaced by the appendix?
caecum
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what is the rectum a temporary store for?
faeces
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what is the rectum part of?
last part of large intestine connects to anus
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what does the rectum shape follow?
the sacrum (bone at bottom of back)
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where does the end of the rectum expand to?
rectal ampulla (food storwed here)
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what causes the desire to defacate?
stretching of rectal walls that stimulates receptors
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what leads to constipation?
voluntary retention (not pooing when you need to) pushes it back up into the colon where more water reabsorbed
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why do we chew?
fruit+ veg have indigestible walls around the nutritious bits, large SA:vol for enzyme, finer particles prevent excoriation (scrapin) of GI + increase ease food is emptied from the stomach
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what do you chew more on, incisors or molars?
molars (90kg)
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what is the chewing reflex?
bolus initiates reflex inhibition of muscle of mastification (MOM)-mandible drop-> stretch reflex of MOM leads to rebound contraction + elevation mandible+teeth close-> compresses bolus against mouth lining of mouth inhibits MOM drops again
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how long is the oesophagus?
20cm
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what is the oesophagus?
muscular tube lined with mucosa
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what is the upper 1/3 of the oesophagus?
skeletal muscle
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what is the lower 2/3s of the oesophagus?
smooth muscle
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position of the oesophagus?
runs posterior to trachea, heart and lungs anterior to vertebrate and pierces the diaphragm before entering the stomach
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what is peristalsis?
constriction and relaxation of muscle creates a wavelike movement
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what is primary peristalsis of the oesophagus?
coniutation of peristaltic wave that commences in oropharynx spreads to oesophagus,
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how long does it take for food to get from the pharyx to stomach? without gravity? with gravity?
without gravity 8-10 secs, with gravity 5-8 seconds
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what is secondary peristalsis?
sweeps down any remaining food,
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what is secondary peristalsis triggered by?
distension of oesophagus
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what are peristaltic waves of skeletal muscle controlled by?
skeletal nerve impulses from- gloosopharyngeal and vagus nerve
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what is the smooth muscle in the oesophagus controlled by?
vagus nerve
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what is barrats oesophagus?
metaplasia of cells lining lower oesophagus as they exposed to stomach acid in reflux oesophagitis
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what do cells change to in barretts oesophagus?
normal stratified squamous epithelium is replaced with simple columnar epithelium with goblet cells lower (GIT cells)
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what has a strong association with barratts oesophagus?
oesophageal adenocarcinoma
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what is oesophageal carcinoma? whats the mortality rate?
a virulent form of cancer 85% mortality rate.
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what is barrats oeophagus if its related to oesophageal adenocarcinoma?
premalignant condition
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what are the symptoms (none in themselves but associated with acid reflux)?
heartburn, dysphagia (prob swallowing), haemtemsis (coughing up blood), sub-sternal pain, erosion of teeth due to acid exposure
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how can barrats oesophagus be treated?
proton pump inhibitor, endoscopic surveilance so can resection of oesophagus
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what shape is the stomach?
J shaped
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what are features of the stomach?
J shaped, muscular, elastic pouch
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what does the stomach do?
churns and partly digests masticated food
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what is the vol of the stomach?
1L usually but from 0.8-1.5L
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length and width of stomach?
30cm x 15cm
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how do you tell your stomach to accomodate more food?
food stretches stomach, stretch recs give a vagovagal relfex from the stomcah to brainstem and back to stomach redicing muscular tone and allowing stomach to bulge outwards for more food
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whaatt is the vagoval reflex?
strech rec in stomach sig to brain sig no stomach to allow more food bulges stomach
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what happens to food once it enters the stomach?
forms concentric circles in the orad portion of the stomach
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where is the old and new food in the stomach?
newest food-by opening of oesophagus, old food-squashed against the walls
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where do gastric glands cover?
almost the entire lumen of the stomach
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where is gastric juice secreted from?
gastric glands
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where does mixing waves become more powerful towards in the stomach?
towards the pylorus
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where does weak mixing waves churning food and gastric secretions begin
mid/upper portion of stomach
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how long does it take food to reach the antrum from coming into stomach?
15-20 seconds
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how much chyme is squirted out through pylorus into dudoenum with each wave?
few millilitres
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what does the pylorius act as as it is slightly tonically contracted?
a sphincter
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what does the pylorus prevent?
food particles passing into the duodenum until they are well mixed and fluid like
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what is the opening and closing of the pylorus controlled by?
NS and hormonal signals from stomach and duodenum
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where are enteroendocrine cells mostly found?
in base of gastic glands
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what do the G cells secrete?
gastrin
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what can the post-gang fibres of the vagus nerve release during parasympa stimulation to stimulate secretion?
gastrin-releasing peptide
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what provides the most important signals for stomach emptying?
duodenum
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what does the rate of somach emptying nerver get greater than?
the rate chyme can be digested and absorbed in the small intestine
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what increases the rate of stomach emptying?
increase food volume in the stomach-stretches the wall eliciting myenteric reflexes, gastrin hormone produced
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what does gastrin hormone do?
mainly causes production of highly acidic gastric juice, mild stimulatory effects on motor activity of pyloric pump
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where is gastrin released from?
produced by G cells in the antral mucosa
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what decreases rate of stomach emptying?
stretch of duodenal wall
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what is the 3 outcomes of decreasing rate of stomach emptying by stretching the duodenum wall?
1) directly inhibits pyloric pump via enteric NS in gut wall 2) extrinsic nerves -> prevertebral sympa ganglia->stomach inhibitory sympa fibres 3) vagus nerves to brainstem -> inhibit excitatory sigs to somach through vagi (only a bit)
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what is a peptic ulcer?
damage to the wall of the stomach by stomach acid, can affect duodenum and lower oesophagus
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what are the symptoms of peptic ulcer?
gnawing, burning, upper abdominal pain that worsens on eating (more acid) indigestion heartburn, nausea
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what is the cause of peptic ulcers?
1) helicobacter pylori (60% gastric. 50-75% duodenal ulcers) 2) non-steroid anti-inflammatory drugs ibuprofen or aspirin for long time at high doeses
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what does helicobacter do to cause peptic ulcers?
causes chronic inflammation in the antral mucosa, acid secretion leads to erosion of gastric wall
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treatment of peptic ulcers?
proton pump inhibitor- reduces acid to near zero allowing ulcer to heal, triple therapy
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what is triple therapy 3 drugs that can induce and remove an ulcer?
amocicillin, clarithromycin and PPI
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where does gatric cancer develop from what is the average age of diagnosis?
devs from lining of stomach, average 69yrs
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what are the symptoms of gastic cancer?
pain or burning sensation on swallowing, food stickin throat or chest, weight loss, upper abdo pain, persistent dyspepsi and burping, feeling full after small amounts as tumour, nausea and comitiing, bleeding (dark stool) tiredness and breathkleness
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what causes gastric cancer?
all bad things eg smoking, obesity etc
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what is the limiting factor for absorption?
surface area over which it occurs
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what are folds of kerckrina?
fold taht increase absorptive surface area by 3 times
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where are fold of kerckring found?
well dev in duodenum + jejunem protrude 8mm into lumen
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villi project from where and by how much?
surface of mucpsa by 1mm
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where do numbers of villi start to decrease?
towards distal end of GI tract
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what does each epithelial cell have in absorptive parts of GI tract?
many 1000s od 1um extensions of microvilli brush moder, 20 fold increase in surface area!
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how is things absorbed structure of intestine?
central lacteal in mid surrounded by venules, arteriols, capillry surrounded by basement membrane, surrounded by brush border
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how is water transported in the small intestine?
entirely by diffusion from high -> low concs, if chyme dilure enough water absorrbed from mucus villi by osmosis entirely
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where does water transport int he small intestine mainly occur?
at tight junctions between apical borders of epithelial cells (paracellular route) but also thro cells (transcellular)
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whats absorbed dialyin terms of carbs, fat, aa, ions and water?
100g+ fat, several hundred g of carbs, 50-110 aa, 50-100g ions, 7-8L of water
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How do ions get reabsorbed by the small intestine?
Na actively transpoted across intestinal membrane
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how much Na is lost in faeces?
less than 0.5%
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what happens ito Na levels with diarrhoea?
inestinal secretions are lost and Na reserves depleted to lethal levels in hours
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how much Na does the small intestine absorb a day?
25-35g/day
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how long is the large intestine?
1.5m length
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how much fluid and electrolytes can the large intestine absorb a day?
5-8L
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what does he large intestine remove?
water, salts, vitamins and sugar
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what are the regions 1st to 5th of the large intestine?
1st) ccecum-compress material into feccal mater 2) ascending colon 3) transverse colon 4) descending colon 5) sigmoid colon
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what are the areas of lymphoid tissue in the large intestine for local immune protection called?
peyers patches
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what are peyers patches teeming with in the large intestine?
bacteria
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whatare the main functions of the large intetine?
1) high mucus secretion 2) no carrier mediated transport of nutrients (all by diffusion) 3)efficient water reabsorption follows Cl and Na 4) HCO2 buffers acid produced by bacterial fermentation
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how much of the time is there segmentted contractions in the colon?
99% of the time
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what are the contractions in the colon that squeeze tight to form faeces and reabsorb water called?
segmented contraftions
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2 parts of segmented contractions?
1) retain material in the proximal colon (water reabsorption+fermentation) 2) mixing contents form faeces
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how much of faeces is water?
3/4
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what is the normal brown colour of faeces caused by?
derivatives of billurubin: 1)stercobilin 2) urobilin
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what is the odour of faeces from?
bacterial action, smell varies for individuals depending on the flora in the colon and food eaten
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what are the odouriderous compounds?
idole, skatole, mercaptans and hydrogen sulphide
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what is the tenia coli in the large intestine?
3 bands of longlitudinal muscle
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what is the haustra in the large intestine?
pockets (segmeted appearance), slow movementof contents, no villi, high conc of gpoblet cells- mcuus secretion
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why is the tight junctions between epithelial cells smaller in the large intestine than the smallintestine?
prevents backflow/backdiffusion of already absorbed ions, allows more Na absorption (esp with aldosterone)
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what absorption does aldosterone greatly enhance?
Na absorption
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why in the large intestine when Na cells are absorbed does it drag Cl with it?
electric potential, diff charges attract
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where is aldosterone produced and secreted?
zona glomerulsa of adrenal glands
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when is aldosterone secreted?
when you are dehydrated
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what does aldosterone do to the large intestine?
within 1-3hrs increased activation of transport and enzyme mechanisms for Na absorption by intestinal epithelium, increased Cl and water absorption
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how are virtually all monosaccjharides absorbed?
by secondary AT processes
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what are the final digestion products of starches?
monosaccharides -> glucose 80% and galactose (milk) and fructose (20%)
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what are co-tranported with Na in the small intestine?
proteins, dipeptides, tripeptides and amino acids
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what are fats broken down into?
monoglycerides and free fatty acids
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broad list of things that control our hunger?
brain receptor, liver, stomach and intestines, fatty tissue, external cues
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3 main fates of nutrients?
1) supply energy 2) provide building blocks 3) stored for duture (glycogen in muscle+liver, triglycerides in adipose tissue
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what building blocks do nutrients give?
muscle proteins, cell membranes, DNA, hormones and enzymes
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what do nutrients supply energy for?
AT, muscle contraction, body temp and DNA reploication
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6 maindietary constituents?
1) proteins 2) carbs 3) fats 4) minerals 5) vitamins 6) water
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3 essential fatty acids?
linoleic acid, liolenic acid, arachidonic acid
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how many aa are required for pro syn?
22
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how many aa can we synthesis from carb precursors?
11
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what are proteins needed for?
essential for growth and repair
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what is the bodys main source of energy?
carbs essential for brain metabolism
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what are minerals?
inorganic elements neccessary to body processes
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how much of the body is water?
60%
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how many of the essential aa can be obtained form the diet?
9
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what cant be synthesised and must be obtained from diet?
essential fatty acids
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if blood glucose begins to drop what does the liver do?
converts glycogen to glucose
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what receptor and where are they in the brain are sensitive to gucose dropping in the blood?
glycoreceptors in hypothalamic cells
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what are the 2 things ain the stomach that tell you you are full?
1) stretch recs 2) chemoreceptors
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what are chemoreceptors in the stomach sensitive to?
small amounts of food dissolved in fluid 'im full' to brain
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what hormone released from the duodenum says to the brain stop eating?
cholecystokinin
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where is cholesystokinin released from?
mucousal cell layer of dudoenum
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3 characteristics of fat cells?
1) fat is longer term energy 2) slower to use 3) more energy per mass than glycogen
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what does adipose tissue (brown fat) releases what?
leptin
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what detects leptin?
hypothalamic recs
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what does lots of leptin in the blood do?
tells hypothalamic recs plenty of fat dont eat
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where is the on switchfor feeding?
lateral hypothalamic
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what is the dual centre hypothesis?
neuropeptide Y = stimulates apeptite but outside hypothalmus so hypothalamus is a centre but not the control cenre are many
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what switch does the ventromedial region of the hypothalamus control?
the off switch
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what does ventromedial lesions to hypothalamus- damage to parasympa syst cause?
more insulin to be secreted
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what is the vicious insulin cycle?
more insulin secreted -> blood glucose falls eat more -> food converted into adipose tissue rather than glucose so stay hungry -> animal eats more fatter -? more insulin secreted
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what explains the loss of apetite after a meal?
hormone secreted by the gut that reaches the brain via the blood stream
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2 hormones that make control hunger?
gherlin or PYY3-36
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what makes PYY3-36?
intestinal cells
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what makes gherlin?
stomach cells
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what makes you hungry?
gherlin from stomach
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what makes you feel full and decrease food uptake?
PYY3-35 from intestinal cells
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how did they prove gherlins the hormone of hnger?
high when fasting, fall after eating, when voluteers given gherlin they ate more than on days with a placebo
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where is PYY3-36 produced?
small and large intestine
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what does PYY3-36 inhibit?
apetite
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what does PYY3-36 do to stop apeptite?
inhibits appetite stimulating neurones by binding to NPY Y2.PYY2-26 recs
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what rec does GYY3-36 bind to?
NPY Y2.PYY2-36
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how does PYY3-36 make you feel?
full and satisfied
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how long do the effects of PPY-3-36 PERSIST?
24 hours after you eat
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what foods give bigger rises in PYY3-36?
slowly digested foods- fats and high fibre foods
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the more calories you eat the bigger the rise in what?
PYY3-36
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one theory to obesity?
reduced sensitivity to PYY3-36, carb diet reduces the rise in PYY3-36 levels after a meal
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why do gherin any PYY3-36 have no side effects?
they are produced by the body and are receptor specific
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why cant there be gherlin and PYY3-36 drugs?
they are peptides, destroyed by stomach so only injection works
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what is the off switch for feeding?
ventromedial hypothalamus
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what percent of our diets should be fats?
30%
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how many kcals per gram is carbs and proteins?
4kcals
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how many kcals per gram is fats?
9kcals (mpore energy per gram)
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how much of our diet should be pro?
13%
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how much of our diet should be carbs?
57%
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where does digeston begin?
in the mouth
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what are the muscles of mastification?
masseter, pterygoids, temporalis
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what are the muscles of masseter innervated by?
V3 (mandibular nerve) of the trigeminal nerve
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what cranial nerve is the trigeminal nerve?
5th
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whatis the position of the oesophagus?
passes posterior to the trachea and he heart and pierces through the diaphragm
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where does the oesophagus enter the stomach?
the fundus
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how long is the oesophagus?
20-25cm long
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what do the layers of the oesophagus constist of?
muscles, mucosa, submuscoa and CT
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what layer performs peristaltic movements to push bolus into stomach?
muscular layer
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where does the stomach lie?
upper left of abdominalcavity against oesophagues
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how long of the stomach churning does it take to produce chyme?
40-60 minutes
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what deos the stomach release?
digestive enzymes, gastric acid, proteases HCL
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whats the function of Hcl in the stomach??
bacericidal, prevents bac from proliferating
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where is the food from the stomach released into in small amounts?
the duodenum
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what knd of structure does the dudoenum have that lies adjacent to the stomach?
C-saped stucture, 25-38cm
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how does the duodenum control stomach emptyng?
hormones- secretin and cholecystokinin
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what is the duodenum important in?
enzymatic breakdown
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villi epithelium is a brush border made up of what?
microvilli
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what increases surface area of jejunum for more absorption of nutrients?
microvilli
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difference between illeum and jejunum?
ileum: has thinner walls and lumen smaller, more fat inside mesentry
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where are peyer patches? (encapsulated lymphoid nodules containing cells from immune syst)
Ileum
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whatis the caecum?
pouch like structure considered to be start of large intestine
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3 function of large intestine (colon)?
1) absorb remaining water+eectrolyte, 2) accepts +stores food remains not digested in SI 3) elimates faeces from body
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what valve does the chyme have to go through from the ileum to the caecum?
ileo-caecal valve
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in what is the caecum bigger why?
herbivores as whre it has cellulose digesting bacteria
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what can caecum be replaced by?
appendix
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what does the rectum follow the shape of?
the sacrum (bone at bottom of back
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where in the rectumis the faeces stored before defaecetion?
in the rectal ampulla
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what causes the desire to defaecate?
stretching of rectal walls -> sitmulates stretch recs
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why do you get constipation?
voluntarily not defaecating pushes it back into the colon where more water will be extracted
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what is the lower gi tracts main role?
absorption of water and electrolytes, elimination
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what is the main role of the small intestine as a whole?
nutrient and water absorption
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what triggers secondary peristaliss in the oesophagus?
distension- sweeps down any remaining food
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what is prmary peristalsis in the oesophagus?
continuaton of peristaltic wave from oropharynx spreads to oesophagus
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how long does food take to get from pharynx to stomach, a) withgravity b) without gravity?
5-8 secs with gravity, 8-10 seconds without
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persitaltic waves of skeletal muscles are controlled by nerve mpulses from what?
Cranial nerves 9 (glossopharyngeal nerve)and 10 (vagus)
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what isthe smooth muscle in the oesophagus controlld by?
vagus nerve
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what happens in barretts oesophagus?
normal stratified squamamous epithelium -> simple columnar with goblet cells (lower GIT cells)
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what is there a storng association with barretts oesophagus (premalignant condition)?
oesophageal adenocarcinoma(virulent form of cancer)
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what is the mortality rate of oesophageal adenocarcinoma?
85%
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what causes barretts oesophagus?
metaplasia of cells lining the lower oesophagus due to exposure to stomach acd in reflux oesophaitis
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what are the symtpoms due to acid reflux in barretts?
heartburn, dysphagia (difficulty swallowing), haemtemsis, sub sternal pain, erosion of teeth
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what can be used to manage barretts oesophagus
proton pump inhibitor, endoscopic surveillance, resection of oesophagus
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how much can the stomach hold without being stretched?
1L
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what does food form when it enters the stomach and where?
forms concentric circles in the orad portion of the stomach
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where is the new food? where is the old food?
new: middle opening of oesophagus,old: squashed against stomach wall
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what reflcts allows the stomach to bulge outward and store up 1.5L?
vagovagal reflex
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how does the vagovagal reflex work?
strecth receptors in the stomach signal to the brainstem and back to the stomach reducing the muscular tone
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what cells of the gastric glands secrete gastrin?
G cells in the antral mucosa
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what stimulates gastrin to be released? what does the vagus nerve release?
parasympathetic stimulation, vpost-gang fibes of cagus nerve releases gastrin-releasing peptide
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how does the pylorus act as a spinchter?
tonically (slowly) contracted , won't let food pass until they're well mixed and fluid like, opens enough to let fluid pass into duodenum
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what cotnrols the opening and closing of the pylorus? from where?
nervous signals and hormones from stomach+duodenum
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where does the waves in the stomach get stronger?
towards the pylorus
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how long does it take to the mixing waves churning food and gastric secretions to reah the antru from mid/upper portion of the stomach?
15-20 seconds
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what 3 things decreases the rate of stomach emptying by stretching the duodenum wall?
1) directly inhibit pyloric pump by enteric NS in gut wall 2) extrinsic nerves ->sympa ganglia inhibitorysympa fibres 3) vagus nerves to brainstem -> inhibit excitatory sigs to stomach through vagi
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what does Gastrin hormone do?
increase the rate of stomach emptying by causing prodction of highly acidic gastric juice+ stimulatory effects on pyloric pump
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other than gastrin what else increases rate of stomach emptying?
increase food vol in stomach stretches walls eliciting myenteric relflexes
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what provides the most potent signals for stomach emptying?
duodenum
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what is the chart for stool caled?
bristol stool chart
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what is the normal brown colour of faeces called?
derivatives of billurubin- urobilin and stercobilin
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what is steatorrhoea?
excess fat in stool
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how much of the 1/4 solid matter in faeces is undigested roughage?
30%
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how much dead bacteria?
30%
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how much of faeces is water?
1/4
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what is the faces odour caused by? why does smell change for diff people?
bacterial action, different colonic flora and food eaten
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what are odouriferous compounds foudn in faeces>
idnole, skatole, mercaptans and hydrogen sulphide
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what are well devloped at the duodenum and jejunim that increase the absorptive SA by 3 times?
folds of Kerckrina
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vili project for the surface of mucsa by 1mm where do numbers start to decrease?
towards the end of the GI tract
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microvill on each epithelial cells give a brush border that increase the SA how many fold?
20 fold
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segmented contractions in the colon occur how much percent of the time?
99%
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what do the segmented contractions do?
1) retain material in proximal colon (water reabsoption+fermentation) 2) mixing contents
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what does heliobactor pylori cause?
60% gastric ulcers 50-75% of duodenal ulcers
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what are the symptoms of a peptic ulcer?
gnawing, bruning, upper abdo pain worses on eaten, indigestion heartburn, nausea
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where can peptide ulcers affect?
lower oesophagus and duodenum
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what is the problem in pepticulcers?
damage to the wall of the stomach by stomach acid
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where does peptic ulcers cause chronic inflammation?
antral mucosa
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in peptic ulcers what erodes due to acid secrtion?
gastric wall of the stomic
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what drugs (non-steroidal anti-inflammatory drugs) can cause peptic ulcers if they are used for a long time or at high doses?
aspirin and ibuprofen
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what is the treatment for peptide ulcers?
proton pumps (no acid anymore), if Heicobactor pylori then trple therapy- amoxicyln, clathithromycin and PPI
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whats the average age of diagnosis of gastric cancer?
69 years
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where does gastric cancer develop from?
the lining of the stomach
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what causes gastric cancer?
all the bad things- alcohol, smoking, obesity
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what is the symptoms of gastric cancer?
nausea+vomiting, feeling full after small amounts, blood in stool, tiredness, breathlessness, persistent dyspepsi+burbing, weight loss, upper abdo pain, pain on swallowing, food sticks in chest or throat
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how is cl dragged into the interstital fluid from the intestine?
by its attraction to Na
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Na absorption from inside epthelial cell to interstial by what?
active transport (sodium potassium ATPases)
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how does sodium move into the epithelial cell from the intestine?
Na-aa co-transporter, Na-glucose co-transporter, sodium-hydrogen exchangers
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pathway of Na from intestine?
aa and glucose co-transportersand Na- hydroge exhnagers bring Na into epithelail cell sodium is being actively pumped out of the cell into the interstitial fluid
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monosaccharides are absorbed by what?
secondary active transport processes
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products of monosaccharide digestion?
80% glucose and galactose and 20% fructose
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how are substances reabsorbed in the small intestine?
doum co-transport mechanism, AT of Na from epithelial cell cyto to interstitial fluid, allows diffusion of Na and other substances by co-transporters, substances move down conc gradient out of cell, Na pumped out by Na/K ATPase
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Card 2

Front

what is the function of the GI tract?

Back

breakdown and absorption of nutrients

Card 3

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how does the GI tract acheive this function?

Back

Preview of the front of card 3

Card 4

Front

what is the diamter and how long is the oesophagus?

Back

Preview of the front of card 4

Card 5

Front

where does the oesophagus carry food to and from?

Back

Preview of the front of card 5
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