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Foundations of Medicine > Week 8 Science and Scholarship: Metabolism and Digestive system > Flashcards

Week 8 Science and Scholarship: Metabolism and Digestive system Flashcards

1
Q

what serous membrane lines the abdominopelvic cavity

A

peritoneum

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2
Q

the kidneys and blood vessels are ___peritoneal

A

extraperitoneal

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3
Q

the stomach and spleen are ___peritoneal

A

intraperitoneal

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4
Q

name the 9 abdominal regions

A

Right hypochondriac Epigastric Left
hypochondriac

Right lumbar umbilical Left lumbar

Right iliac hypogastric Left iliac

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5
Q

describe the transpyloric plane

A

-lies equidistant to the superasternal notch and pubic symphysis

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6
Q

describe the embryology of the GI tract

A

*5-7 metre tube that connects the mouth to the anus
*4 layers
*3 segments

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7
Q

name the 4 layers of the GI tract

A

-mucosa
-submucosa
-muscularis externa /(muscularis propria)
-serosa/(adventitia)

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8
Q

name the 3 segments of the GI tract

A

foregut (superior)
midgut (middle)
hindgut (inferior)

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9
Q

what artery supplies each segment of the GI tract

A

foregut = coeliac artery
midgut = superior mesenteric artery
hindgut = inferior mesenteric artery

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10
Q

where is pain localised for each segment of GI tract

A

foregut = epigastric area
midgut = periumbilical area
hindgut = suprapubic area

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11
Q

function of mouth in digestion

A

contains teeth for mastication (chewing), mechanical digestion

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12
Q

function of oesophagus in digestion

A

conduit between mouth and stomach

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13
Q

function of stomach in digestion

A

mechanical digestion and little absorption

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14
Q

function of duodenum

A

digestion due to the arrival of pancreatic juice and bile allowing for significant absorption

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15
Q

identify components of upper GI tract

A

oesophagus
stomach
duodenum

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16
Q

structure of oesophagus

A

-25 cm peristalsis tube
-lined by squamous more proximal and columnar epithelium distally
-contains oesophageal sphincter

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17
Q

function of gastro-oesophageal junction

A

prevents (acid) reflux of food and hallmarks the transition from squamous to columnar epithelium

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18
Q

whats acid reflux

A

condition in which the GOJ closing is impaired, the contents of the stomach (including its acid) is regurgitated and enters oesophagus

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19
Q

structure of stomach

A

-J shaped organ with 4 regions
-highly acidic (1.5-3.5)
-largely variable in size
-has two openings which are joined by two curvatures
-doesn’t absorb foods, more so fluids eg alcohol, water

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20
Q

what are the two openings into the stomach

A

oesophageal + duodenum

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21
Q

what are the two curvatures of the stomach

A

the greater and lesser curvature

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22
Q

describe blood supply to the stomach

A

-stomach in foregut hence supplied by coeliac trunk
-coeliac trunk divides into 3 arteries : left gastric, common hepatic and gastroduodenal arteries
-the gastroduodenal artery forms the gastro-mental network that forms around the greater curvature
-the left gastric artery forms the gastric network that forms around the lesser curvature

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23
Q

function of pharynx in digestion

A

upper portion of the conduit between mouth and stomach

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24
Q

function of salivary glands in digestion

A

secretions help in lubrication , are antibacterial and begins digestion

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25
Q

function of small intestine in digestion

A

digestion and most absorption (with help of pancreatic and liver secretions)

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26
Q

function of large intestine in digestion

A

completion of absorption of water and electrolytes (faeces remains)

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27
Q

function of rectum in digestion

A

final part of large intestine where faeces are stored prior to defecation

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28
Q

function of anus in digestion

A

terminal part of GI tract where faeces are propelled into extracellular environment

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29
Q

function of gall bladder in digestion

A

Storage : store bile products between meals
Concentration: concentrates bile products by removing and clearing fluids
Regulation:regulates systemic release of bile during meals

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30
Q

function of pancreas in digestion

A

vital for digestion, contains enzymes for the digestion of all food categories

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31
Q

features of mucosa layer of GI wall

A

innermost layer
-contains epithelium, lamina propria and muscularis mucosa

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32
Q

features of submucosa layer of GI wall

A

layer beneath mucosa
-contains blood vessels, lymphatic tissue and nerves that provide support and nutrition to the submucosa

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33
Q

features of muscularis externa layer of GI wall

A

-responsible for rhythmic contractions of GI tract that are propel food through digestive system

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34
Q

features of serosa layer of GI wall

A

outermost layer
-secrets slippery fluid to reduce friction and facilitate movement within the abdominal cavity

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35
Q

name 4 main processes in digestion

A

motility
secretion
digestion
absorption

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36
Q

what is digestion stage

A

mechanical and biochemical breakdown of foods into smaller units
-hydrolysis of water

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37
Q

whats is absorption stage

A

small units (with water and electrolytes) are transferred into blood / lymph
-achieved by sodium-depended symport

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38
Q

what is secretion stage

A

exocrine glands secrete digestive juices and endocrine glands release hormones

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39
Q

what is motility stage

A

muscular contractions that propel (peristalsis) and mix (segmentation) foods, highly regulated by nerves

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40
Q

what substance(s) does mouth release

A

saliva (salivary amylase, mucous and lysozymes)

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41
Q

what substance(s) does pharynx/oesophagus release

A

mucous

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42
Q

what substance(s) does liver/gall bladder release

A

bile (bile salts, alkaline secretions and bilirubin)

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43
Q

what substance(s) does exocrine pancreas release

A

digestive enzymes (trypsin, chymotrypsin, amylase and lipase)

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44
Q

what substance(s) does stomach release

A

gastric juices (HCl, pepsin, mucous, intrinsic factor)

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45
Q

what substance(s) does small intestine release

A

succus entericus, enzymes

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46
Q

Name the factors that regulate digestive function with a focus on neural components and smooth muscle.

A

Autonomous smooth muscle function
Intrinsic nerve plexuses
Extrinsic nerves
Gut hormones

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47
Q

Explain how autonomous smooth muscle regulates digestive function

A

smooth muscle is able to contract rhythmically without neural input, which is regulated by specialised pacemaker cells (cajal cells)

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48
Q

Explain how intrinsic nerve plexuses regulates digestive function

A

network of nerve fibres located in the walls of digestive system that regulates functions eg motility and secretion

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49
Q

Explain how extrinsic nerves regulates digestive function

A

responsible for regulating functions like motility, secretion and blood flow by communicating with CNS

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50
Q

Explain how GI hormones regulates digestive function

A

chemical messengers produced and secreted by cells lining the digestive tract that regulate various functions eg digestion, hunger, absorption

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51
Q

Describe the components of saliva

A

water (99.5%), carbohydrate (0.5%) and protein (<0.01%)
-contains mucous, amylase, lingual lipase, lysozyme and bicarbonate buffer

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52
Q

function of saliva

A

washes particles away and acts as a solvent for taste

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53
Q

name the two reflexes for increased saliva secretion

A

conditioned and simple reflex

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54
Q

describe the conditioned reflex for increases saliva

A

Receptor: taste receptors on tongue
Afferent nerve: taste fibres of the facial and glossopharangyeal nerve
Control centre: higher centres of the brain including cerebral cortex
Efferent nerves: parasympathetic fibres of facial and glossopharangyeal nerve
Effector: salivary glands
Response: increased saliva secretion

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55
Q

describe the simple reflex for increased saliva

A

Receptor: chemoreceptors in the oral cavity
Afferent nerve: glossopharangyeal nerve and trigeminal nerve
Control centre: salivary centres in medulla oblongata
Efferent nerves: parasympathetic fibres of glossopharangyeal nerve
Effector: salivary glands
Response: increased salivary secretion

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56
Q

name salivary glands

A

parotid
sublingual
submandibular

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57
Q

Name the stages of swallowing

A
  1. oral phase
  2. pharangyeal phase
  3. oesophageal phase
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58
Q

describe oral phase of swallowing

A

-tongue moves bolus to back of mouth triggering swallowing reflex
-causes soft palate to close off the nasal cavity
-causes epiglottis to close off the larynx

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59
Q

describe pharangyeal phase of swallowing

A

-bolus enters the pharynx
-triggering series of involuntary reflexes that move it into oesophagus

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60
Q

describe oesophageal phase of swallowing

A

-bolus is propelled down oesophagus by peristalsis until it reaches stomach

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61
Q

name the two sphincters in oesophagus

A

pharyngo-oesophageal sphincter
gastro-oesophageal junction/ sphincter

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62
Q

function of pharyngo-oesophageal sphincter

A

prevents excess air from entering GI tract

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63
Q

name 3 regions of stomach

A

fundus
body
antrum

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64
Q

difference between body and antrum of stomach

A

there is differences in glandular mucosa (secretions and cells)

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65
Q

identify the functions of the stomach

A

-storage of food
-secretion
-chyme

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66
Q

Describe what is meant by the stomach is involved in ‘storage of food’

A

regulates the controlled release of food into the small intestine

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67
Q

Describe what is meant by the stomach is involved in ‘secretion’

A

secretes enzymes and HCl to enable protein digestion

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68
Q

Describe what is meant by the stomach is involved in ‘chyme’

A

food and secretions are mixed to create acidic chyme

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69
Q

briefly what happens in gastric filling

A

-eating triggers the relaxation of folds within the mucosa (gastric Rugae) in a process called receptive relaxation
-however, intragastric pressure doesn’t change because of he rugae flattening

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70
Q

briefly what happens in gastric mixing

A

-regulated by smooth muscle in walls of stomach
-pacemaker cells generate slow wave potentials
-slow wave potentials set the basic electrical rhythm of the heart
-muscles in wall contract due to slow wave potentials
-these contractions allow for gastric mixing

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71
Q

briefly describe what happens in gastric emptying

A

-process in which food leaves stomach into small intestine
-regulated by rate at which pyloric sphincter opens
-gastric emptying is influenced by size of meal, presence of nutrients in small intestine, neural and hormonal signals form gut

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72
Q

whats gastroperesis + symptoms, causes

A

-Gastroparesis: stomach empties slowly
-Symptoms: nausea, vomiting, stomach pain, bloating, feeling full fast
-Causes: vagus nerve damage, diabetes, autoimmune diseases, certain meds

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73
Q

whats achalasia + symptoms, causes

A

-Muscles in the lower oesophageal sphincter (LES) don’t relax properly.
-Symptoms include trouble swallowing, food coming back up, chest pain, heartburn, and weight loss.
-Nerve damage in the oesophagus often causes achalasia.

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74
Q

identify the local and distal factors that controls gastric motility and emptying

A

stomach: volume of chyme
stomach: fluidity
Duodenum: fat
Duodenum: acid
Duodenum: hypertonicity
Duodenum: distension
External: emotion and pain

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75
Q

describe how stomach: volume of chyme controls gastric motility and emptying

A

proportional to distension (stretch, intrinsic plexus, vagus nerve, gastrin)

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76
Q

describe how stomach: fluidity controls gastric motility and emptying

A

more easily emptied (must reach threshold fluidity to empty)

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77
Q

describe how duodenum: fat controls gastric motility and emptying

A

slowly digested, needs time process fat already there

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78
Q

describe how duodenum: acid controls gastric motility and emptying

A

chyme must be neutralised, or it inactivates enzymes and irritates duodenal mucosa

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79
Q

describe how duodenum: hypertonicity controls gastric motility and emptying

A

amino acids and glucose draws water from plasma to reach isotonicity

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80
Q

describe how duodenum: distension controls gastric motility and emptying

A

too much chyme leads to excess volume

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81
Q

describe how external: emotion and pain controls gastric motility and emptying

A

varies autonomic balance, activates ANS and decrease motility

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82
Q

secretin and CCK ____ _____ contractions

A

inhibit antral contractions

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83
Q

what regulates short and long reflexes

A

intrinsic nerve plexuses and autonomic nerves

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84
Q

emesis =

A

vomiting

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85
Q

name factors that can cause emesis

A

-tactile stimulation of the back of throat
-elevated intracranial pressures
-chemical factors
-irritation or distention of the stomach and duodenum
-vestibular/visual cues (motion sickness)
-psychogenic (mental/emotional factors)

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86
Q

Describe process of vomiting

A

1.coordinated by vomiting centres of medulla in brainstem
2.deep inspiration; glottis is closed uvula raises
3.stomach, oesophagus and gastro-oesophageal sphincter relax
4.respiratory muscles contract, stomach is squeezed between descending diaphragm and increasing intra-abdominal pressure
5.sensation of nausea , salivation , sweating, tachycardia regulated by ANS
6. Excess vomiting results in loss of fluids and acids

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87
Q

identify the exocrine secretory cells

A

mucous cells
chief cells
parietal cells

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88
Q

identify endocrine secretory cells

A

ECL cells
G cells
D cells

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89
Q

what do mucous cells secrete, the stimulus and function

A

secretion : alkaline mucous
stimulus: mechanical stimulation by gastric contents
function: protects mucosa against mechanical, pepsin and acidic injury

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90
Q

what do chief cells secrete, the stimulus and function

A

secretion: pepsinogen
stimulus: Ach
function: initiates protein digestion

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91
Q

what do parietal cells secrete, the stimulus and function

A

secretion: HCl, intrinsic factor
stimulus: Ach, gastrin and histamine
function : activates pepsinogen, breaks down CT, denature proteins, kill microorganisms, facilitate vitamin B12 absorption

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92
Q

what do ECL cells secrete, the stimulus and function

A

secretion:histamine
stimulus: Ach , gastrin
function: stimulates parietal cells

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93
Q

what do G cells secrete, the stimulus and function

A

secretion: gastrin
stimulus: protein products, Ach
Function: stimulates parietal, chief and ECL cells

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94
Q

what do D cells secrete, the stimulus and function

A

secretion: somatostatin
stimulus:acid
function: inhibits G, parietal and ECL cells

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95
Q

identify the 3 phases of gastric secretion

A

cephalic, gastric and intestinal

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96
Q

Describe cephalic phase of gastric secretion

A

-triggered by thought/thinking
-mediated by P.S NS, stimulates gastric secretion before food enters stomach

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97
Q

describe gastric phase of gastric secretion

A

-triggered by food entering stomach
-mediated by gastrin, which simulates secretion of gastric acid and enzymes

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98
Q

describe intestinal phase of gastric secretion

A

-triggered by chyme entering duodenum
-mediated by enterogastric reflexes and hormones eg gastrin, CCK, gastric inhibitory peptide

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99
Q

function of gastric mucosal barrier

A

helps gastric mucosa withstand strong acid and proteolytic enzymes

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100
Q

name 4 elements of gastric mucosal barrier

A

epithelial cells
tight junctions
mucosa
bicarbonate

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101
Q

describe elements of gastric mucosal barrier

A

epithelial cells: impenetrable to HCl
tight junctions:prevent acid diffusing between cells
mucosa: prevents physical penetration of HCl
bicarbonate: neutralised acid and inactivates pepsin

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102
Q

structure of small intestine

A

-hollow tube between 5-7 metres long
-three segments, duodenum, jejunum and ileum

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103
Q

describe functions of the small intestine

A

-absorption: utilises specialised epithelial cells to uptake nutrients from digested food

-secretion: release enzymes (maltase, lactase) to further beak down food molecules

-immunity: houses lymphoid tissue to to protect against foreign substances and pathogens

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104
Q

describe motility patterns in the small intestine

A

-segmentation (primary motility method), involves oscillating ring like contractions, this is done in an alternate manner leading to ‘Mexican wave’, mixing food with chyme

105
Q

how is segmentation regulated in small intestine

A

-pacemaker cells (cajal) generate basic electrical rhythm
-extrinsic nerves influences by P.S NS and SNS regulate strength of contraction, while smooth muscle responsiveness is regulated by distention

106
Q

whats another name for the gastrointestinal housekeeper

A

migrating motility complex (MMC)

107
Q

What does the MMC do

A

moves chyme forward once most nutrients have been absorbed

108
Q

Outline each phase of the MMC

A
  1. (40-60 mins) relatively quiet, few contractions
  2. (20-30 mins) some, inconsistent contractions
  3. (5-10 mins) intense peristaltic contractions that propagate from the upper stomach to the end of small intestine (growling)
109
Q

what hormones regulates MMC

A

motilin

110
Q

what is the ileocaecal juncture

A

the valve between the small and large intestine (caecum)

111
Q

name the secretions of the pancreas and what cell relates them

A

duct cells:
Na2CO3 solution

Acinar cells:
proteolytic enzymes
pancreatic amylase
pancreatic lipase

112
Q

function of NA2CO3 solution secreted by pancreas

A

maintains alkaline environment in pancreas

113
Q

function of proteolytic enzymes secreted by pancreas

A

protein digestion

114
Q

function of pancreatic amylase secreted by pancreas

A

carbohydrate digestion
-polysaccharides into disaccharides

115
Q

function of pancreatic lipase secreted by pancreas

A

fat digestion
-triglycerides into monoglycerides

116
Q

name the three pancreatic proteolytic enzymes (inactive)

A

trypsinogen
chymotrypsinogen
procarboxypeptidase

117
Q

trypsin = ___ + ____

A

enterokinase + trypsinogen

118
Q

chymotrypsin = ___ + ____

A

trypsin + chymotrypsinogen

119
Q

carboxypeptidase = ___ + ____

A

trypsin + procarboxypeptidase

120
Q

Outline steps in neutralisation of duodenum

A

1.acid in duodenal lumen
2.secretin released from duodenal mucosa
3.secretin is carried by blood to pancreatic duct cells
4.pancreatic duct sells secrete NaHCO3- solution into duodenal lumen

121
Q

Outline steps of digestion in duodenum

A

1.fat and protein products in duodenal lumen
2.CCK released from duodenal mucosa
3.CCK is carried by blood into pancreatic acinar cells
4.secretion of pancreatic digestive enzymes into duodenal lumen

122
Q

describe structure of liver

A

-comprised of hexagonal lobules, each lobule has a central vein and three peripheral tubes
-contains Kupfer cells, erythrocytes, sinusoids, hepatocytes, bile canaliculis, Peripheral bile duct and common bile duct

123
Q

what are sinusoids in liver

A

capillary like blood vessels found between hepatocyte plates

124
Q

what are kupfer cells in liver

A

hepatic macrophages that reside in sinusoids

125
Q

what are hepatocytes’ role in liver

A

primary functional cells of liver, responsible for metabolism

126
Q

what are bile canaliculi in liver

A

tiny ducts between hepatocytes for bile drainage

127
Q

what are peripheral bile ducts

A

ducts collecting bile from bile canaliculi

128
Q

what is the common bile duct

A

main duct carrying bile from liver to duodenum

129
Q

functions of liver

A

-digestion
-secreting bile salts to breakdown and absorb fats in small intestine

130
Q

outline blood flow to the liver

A

-two main sources arterial blood (via hepatic artery) and venous blood (through hepatic portal vein)
-venous blood supplies nutrient rich blood to sinusoids

131
Q

structure and location of gall bladder

A

-small, pear shaped organ located underneath liver in URQ

132
Q

outline flow of bile

A

During meals : L/R hepatic duct, common hepatic duct, bile duct, sphincter of oddi, duodenum

After meals: L/R hepatic duct, common hepatic duct, bile duct, cystic duct

133
Q

name two processes of bile production

A

emulsification and micelle formation

134
Q

what is emulsification

A

breakdown of fat globules into smaller droplets by bile salts

135
Q

what is micelle formation

A

creation of small lipid soluble clusters for fat absorption

136
Q

what are micelles

A

-have a hydrophobic core and hydrophilic shell
-if cholesterol secretion surpasses the ability of micelles this can lead to gall stones

137
Q

how much bile is reabsorbed by active transport

A

95%

138
Q

substances that increase the secretion of bile are known as ___

A

choleretics eg CCK

139
Q

how is bile secretion regulated

A

via
Chemical factors
Hormonal factors
Neural factors

140
Q

How do chemical factors regulate bile secretion

A

bile salts stimulate their own secretion when returned to the liver in digestion

141
Q

How do hormonal factors regulate bile secretion

A

secretin stimulates release of NaHCO3- solution to neutralise gastric chyme

142
Q

How do neural factors regulate bile secretion

A

vagal stimulation of the liver increases bile flow during the cephalic phase

143
Q

features of bilirubin

A

-2nd major component of bile
-yellow t/f contributes to jaundice
-waste product of digestion
-modified bilirubin is reabsorbed, unmodified is removed via urine

144
Q

whats hepatitis

A

-inflammatory disease of liver
-can lead to sorosis or failure
-

145
Q

causes of hepatitis

A

virus, toxins, alcohol , autoimmune

146
Q

symptoms of hepatitis

A

jaundice
fatigue
abdominal pain
loss of appetite

147
Q

Describe how carbohydrates are converted from macronutrients into absorbable units

A
  1. amylase breaks down polysaccharides into disaccharides and oligosaccharides
    2.membrane bound enzymes (anchored to brush borders of enterocytes) break down disaccharides and glucose oligomers into monosaccharides
  2. absorption of monosaccharides with two sodium ions via secondary active transport, water follows to maintain osmotic balance
148
Q

Describe how lipids are converted from macronutrients into absorbable units

A

1.ingested lipids (large droplets) are emulsified by bile salts and motility
2.emulsion droplets are digested by lipase and converted to monoglycerides and FFA’s
3.co-lipase binds to emulsion droplets, packaging these into micelles and moving them through the intestine to the surface of the cell
4.passive absorption of end products; micelles release their contents at cell membrane
5.end products are resynthesised into TAG, which forms a hydrophilic chylomicron that is released into the lymph via exocytosis

149
Q

Describe how proteins are converted from macronutrients into absorbable units

A

1.endogenous and exogenous proteins are broken down into amino acids (one or two step process)
2.digestion of proteins occurs via tertiary active transport dependent on H+, Na+ and energy
3.amino acids exit the cell via facilitated diffusion and diffuse into capillary

150
Q

what glucose transporter does glucose use for entry and exit

A

entry = SGLT-1
exit = GLUT-2

151
Q

what glucose transporter does galactose use for entry and exit

A

entry = SGLT-1
exit = GLUT-2

152
Q

what glucose transporter does fructose use for entry and exit

A

entry= GLUT-5
exit=GLUT-2

153
Q

Describe how carbohydrates are transported from GI tract into liver/tissues

A

absorbed as monosaccharides and transported via bloodstream to tissues for energy or stored as glycogen in liver

154
Q

Describe how amino acids are transported from GI tract into liver/tissues

A

broken down into amino acids and transported via bloodstream to tissues for protein synthesis or energy production

155
Q

Describe how lipids are transported from GI tract into liver/tissues

A

absorbed as fatty acids and glycerol, packaged into chylomicrons, transported via lymphatic system and then delivered to tissues or stored in adipose tissue for energy or structural purposes

156
Q

name two types of lipoproteins

A

HDL’s and LDL’s

157
Q

role of HDL’s

A

returns cholesterol to liver (or bile)

158
Q

role of LDL’s

A

delivers cholesterol to cells in body

159
Q

name the segments of the large intestine

A

1.caecum
2.ascending colon
3.transverse colon
4.descending colon
5.sigmoid column
6.rectum
7.anal canal

160
Q

structure of large intestine

A

-contain ‘haustra’, divided pouches of the column seen from caecum to rectum
-‘haustral formation’ (change in location) is caused by contractile activity of the circular muscle layer
-taeniae coli are also found, seperate bands of longitudinal muscles, these layers are gathered in haustral pouches
-the myenteric plexus is concentrated beneath the taeniae coli

161
Q

brief histology of large intestine

A

-mucosa, submucosa and muscularis externa but no vili (t/f decreasing SA)

162
Q

features of motility in the large intestine

A

-two main types of movements, haustral contractions and mass movements
-these help regulate movement and absorption of water and nutrients in large intestine (faeces form)

163
Q

describe haustral contractions

A

slow, segmenting movements that occur in the haustra, pouches along colon, this aids in water and electrolyte absorption

164
Q

describe mass movements

A

powerful peristalsis waves that propel faecal matter over long distances (1 to 3 times a day), facilitating defecation

165
Q

Describe how intrinsic innervation regulates large intestine motility

A

regulates via the myenteric plexus concentrated beneath the taeniae coli

166
Q

Describe how extrinsic innervation regulates large intestine motility

A

Parasympathetic NS: innervation via vagus nerve (proximal colon) and pelvic nerve (distal colon)
Sympathetic NS: innervation via superior mesenteric ganglion (proximal colon), inferior mesenteric ganglion (distal colon), hypogastric plexus (rectum and anal canal)

167
Q

what regulates haustral contractions itself

A

mediated by reflexes (linked to slow wave AP’s)

168
Q

what controls mass movements itself

A

neural and hormonal stimuli predominantly after a meal

169
Q

Outline steps in gastrocolic reflex

A

1.food enters stomach
2.release of gastrin and activation of extrinsic autonomic nerves
3.stimulation of colon motility (mass movement)
4.pushes content into rectum, leads to urge to defecate

170
Q

what is defecation

A

-removal of dried out faeces from the body
-involves involuntary control (myenteric plexus, spinal chord and cerebrum)
-involves voluntary control (abdominal contractions, pelvic floor relaxation)

171
Q

what is Hirschsprung’s disease

A

absence of enteric innervation results in enlargement of colon

172
Q

describe the absorptive mechanisms of the colonic epithelium

A

-absorptive enterocytes in colon enable transport of water out faeces
-these cells absorb Na+ and Cl-, water follows snd osmotic balance is retained

173
Q

name some components of faeces

A

water
cellulose
bacteria
ions
bilirubin

174
Q

describe the secretive mechanisms of the colonic epithelium

A

-no digestive enzymes in colon
-secretes a protective alkaline mucous, neutralises acid and lubricates): this is mediated by short reflexes and parasympathetic innervation

175
Q

short vs long reflexes

A

short reflexes are local, intrinsic reflex arcs within the ENS
while
long reflexes involve more complex neural pathways that extend to the CNS and back to the GI tract.

176
Q

name the GI microbiota in fermentation and health

A

colon microflora
colon fermentation
bacteria and flatulence

177
Q

how does colon microflora play a role in gut health

A

-rapid increase in Bacteria in ileocecal valve, humans have a symbiotic relationship
-mostly anerobes, raise acidity
-synthesis of vitamin K and promote Ca, Mg, Zn absorption

178
Q

how does colon fermentation play a role in gut heath

A

-microbiotas contribute to hosts mechanism through fermentation
-produce enzymes that breakdown nutrients that can’t otherwise be hydrolysed
-excess products eg FA’s, gases , glucose

179
Q

how does bacteria and flatulence play a role in gut health

A

-gas passed from anus is called ‘flatus
-comprised from non digestible carbs
-can be sign of functional gut health

180
Q

what can cause food poisoning

A

salmonella and campylobacter
-bacteria pass epithelium and cause inflammation

181
Q

what neurotransmitter plays a key role in salivation

A

Ach

182
Q

what is xerostomia

A

-hyposalivation or excess salivary clearance

183
Q

causes of xerostomia

A

medications
damage to salivary glands
cancer treatment
dehydration
Sjorgen’s syndrome

184
Q

how can xerostomia be treated

A

saliva substitutes and pilocarpine

185
Q

whats dysphagia

A

reduced laryngeal closure –> aspiration (disruption in swallowing process)

186
Q

outline control of sphincters

A

upper=neurally induced tonic contraction
lower=myogenic activity

187
Q

what happens in reflux oesophagifits

A

(heartburn)
-LES relaxes, upon inspiration, intrapleural pressure decreases and the oesophagus expands, lower pressure in the oesophageal lumen pulls acidic content into the oesophagus

188
Q

how do peptic ulcers occur

A

-H.pylori resides in mucous layer, towards the antrum and produces urase breaking down NH3 as the buffer
-H.pylori secretes toxins that cause inflammation (gastritis) and disrupting tight junctions in the epithelium and increasing (high pH gastrin) increasing the release of HCl to try decrease pH leading to peptic ulcers.

189
Q

how does biliary obstruction occur

A

-most common cause is choleliths, other causes include malignancy, infection, cirrhosis
-jaundice occurs
-it is the blockage of any duct that carries bile from the liver to gall bladder to small intestine

190
Q

how does pancreatitis occur

A

-inflammation of the pancreas, pancreatic enzymes irritate and damage the pancreas
-can lead to tissue loss, necrosis, pain

191
Q

what duct blockage causes biliary obstruction

A

cystic duct and CBD

192
Q

what duct blockage causes pancreatitis

A

CBD and pancreatic duct

193
Q

what is celiac disease/gluten enteropathy

A

intolerance to gluten, caused by shortened vili and and reduced SA of small intestine
-can lead to malnutrition

194
Q

what is diverticular disease

A

herniation of the sigmoid colon, causes inflammation of the diverticula

195
Q

define metabolism

A

the chemical reactions in an organism that maintain life

196
Q

define intermediary metabolism

A

reactions involving the degradation, synthesis, and transformation of energy rich organic molecules (carbs, fats,proteins)

197
Q

define catabolism

A

degradation of larger macromolecules eg hydrolysis or oxidation

198
Q

define anabolism

A

synthesis of larger macromolecules eg condensation

199
Q

describe the fates of absorbed fuel units

A

metabolic pool-fuels are converted into intermediate metabolites to enter metabolic pathways for energy production or biosynthesis of biomolecules
stored-excess fuel in body is stored as glycogen in liver and muscle or triglycerides in adipose tissue
utilised-fuel is oxidised through ACR to produce ATP

200
Q

how are different fuels metabolised

A

-glucose can be used for anaerobic or aerobic
-AA and FA’s are only used for aerobic

201
Q

name the three stages in ATP production (ACR)

A

-glycolysis
-krebs cycle
-electron transport chain

202
Q

describe glycolysis

A

-glucose is split into two pyruvate
-2 ATP produced
-aerobic and anaerobic

203
Q

describe Krebs cycle

A

-pyruvate converted into acetyl CoA
-citrate, ATP, NADH and FADH2 produced
-aerobic

204
Q

describe electron transport chain

A

-conversion of energy from NADH and FADH2 into ATP via mitochondrial enzymes
-aerobic

205
Q

describe insulin and glucagon in regulating fuel metabolism (fed state)

A

-High insulin levels
-Promotes glucose uptake and utilization
-Stimulates glycogen synthesis
-Inhibits glycogen breakdown
-Facilitates triglyceride synthesis

206
Q

describe insulin and glucagon in regulating fuel metabolism (fasting state)

A

-Decreased insulin levels
-Increased glucagon levels
-Promotes glycogen breakdown and- gluconeogenesis
-Enhances lipolysis
-Increases blood glucose levels

207
Q

role of liver in BGL control

A

-Storing extra glucose as glycogen when eating.
-Making new glucose from non-carb sources when fasting.
-Breaking down stored glycogen into glucose when needed.
-Releasing glucose into the blood for energy.

208
Q

name factors effecting energy requirements

A

body size
activity
sex
body composition
age
hormonal status

209
Q

define basal metabolic rate

A

energy expended by the body to maintain basic physiological functions at rest, such as breathing, circulation and temperature regulation

210
Q

how to calculate BMR in men and women

A

M: (10 x weight) + (6.25 x height) - (5 x age) + 5

F: (10 x weight) + (6.25 x height) - (5 x age) -16

211
Q

list the main classes of macronutrients

A

fats
carbs
proteins
fibres

212
Q

function of fats

A

energy storage, protection of organs, insulation and absorption of fat soluble vitamins

213
Q

function of carbs

A

primary source of energy for the body, fuel

214
Q

function of proteins

A

building block of cells and tissues, growth, maintenance and repair

215
Q

function of fibres

A

promotes health digestion and aids in bowel regularity, regulates BGL and cholesterol

216
Q

sources of fats in food

A

oils and butter

217
Q

source of protein in food

A

meat and poultry

218
Q

source of carbs in food

A

poultry

219
Q

source of fibres in food

A

wholegrain

220
Q

is there digestive enzymes in colonic epithelium

A

no, digestion completed

221
Q

pain in right scapula is indicative of

A

gall bladder pathology

222
Q

pain radiating from epigastric region to back is indicative of

A

pancreatitis or perforated peptic ulcer

223
Q

pain radiating from loin to groin is indicative of

A

ureteretic colic

224
Q

pain radiating from periumbilical area to RIF

A

appendicitis

225
Q

leukonychia is indicative of

A

hypoalbuminaemia due to chronic liver disease

226
Q

Koilonychia is indicative of

A

chronic iron deficiency anaemia

227
Q

clubbing is indicative of

A

liver cirrhosis, IBD and coeliac disease

228
Q

pallor of palmar creases are indicative of

A

anaemia

229
Q

dupuytrens contracture is indicative of

A

genetics, age or manual labour

230
Q

hepatic flap (asterixis) are indicative of

A

hepatic encephalopathy due to chronic liver disease

231
Q

palmar erythema is indicative of

A

chronic liver disease

232
Q

ecchymoses is indicative of

A

clotting abnormalities due to hepatocellular damage interfering with clotting factors

233
Q

petechiae are indicative of

A

thrombocytopenia due to splenomegaly

234
Q

what is muscle wasting indicative of

A

late manifestation of malnutrition in alcoholic pt

235
Q

what is spider naevi indicative of

A

cirrhosis due to pregnancy alcohol, virus, hepatitis

236
Q

what is acanthosis nigricans indicative of

A

GI carcinoma, acromegaly, diabetes mellitus

237
Q

what are scratch marks indicative of (chronic cholestasis)

A

pruritus due to obstructive/cholestatic jaundice or primary biliary cirrhosis

238
Q

what is scleral jaundice indicative of

A

congestive heart failure leading to hepatic congestion

239
Q

what is conjunctival pallor indicative of

A

anemia

240
Q

what are Kayser-Fleisher rings indicative of

A

liver disease or Wilson’s disease

241
Q

unilateral enlargement if parotids indicates

A

tumour

242
Q

bilateral enlargement of parotids indicates

A

alcohol use

243
Q

gum hypertrophy and mouth ulcers indicate

A

numerous causes

244
Q

tongue coatings indicative of

A

disease or smoking

245
Q

leukoplakia is indicative of

A

maybe oral cancer

246
Q

glossitis is indicative of

A

atrophy of the papillae

247
Q

fetor hepaticus is indicative of

A

severe parenchymal liver disease

248
Q

angular stomatitis is indicative of

A

vitamin B(6) and B(12), folate and iron deficiency

249
Q

enlargement of the cervical or supraclavicular lymph nodes indicates

A

infection of mouth, pharynx,
-oropharangyeal malignancy

250
Q

enlargement of Virchow’s node (left supraclavicular node) is indicative of

A

metazoic spread of gastric cancer

251
Q

gynaecamastia is indicative of

A

chronic liver disease

252
Q

hair loss is indicative of

A

liver disease

253
Q

caput medusae is indicative of

A

portal HTN

254
Q

when is ascites present

A

when percussion is dull but then turns resonant (after 30s and manoeuvre)

255
Q

whats ileus

A

lack of bowel movements in intestines

256
Q

renal bruits indicate

A

renal artery stenosis

257
Q

pitting oedema is indicative of

A

hypoalbuminaemia

258
Q
A

Foundations of Medicine (18 decks)

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