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Flashcards in Digestive system Deck (104)
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1

peritoneal relationship of LI

ascending colon, descending colon and rectum are retroperitoneal
appendix, transverse colon, sigmoid colon are intraperitoneal
caecum is variable

2

distinguishing features of the large intestine

semilunar plicae --> internal mucosal folds that are not complete circular.

haustra --> one haustrum is bordered by two neighbouring semilunar plicae, because tania are shorter than the length of the large intestine giving rise to sacculations

tenia coli --> 3 band like structures compose of segregated outer longitudinal muscular layer

epiploic appendages --> fat filled peritoneum projecting from right and left borders of the free tania. are more common in transverse and sigmoid colon

3

tenia coli

mesenteric tenia : attached to mesentery
mental ténia : attached to greater momentum
Free tania: is free from any attachment (epiploic appendages attach on its right and left borders)

4

function of the large intestine

reabsorb water and electrolytes and create solid waste

ascending and transverse = involved in reabsorption of water and electrolytes = processing units

descending and sigmoid colon = involved in storage of faeces = storage units

rectum and anu = involved in elimination of faces = elimination units

5

blood supply of colon and superior rectum

appendix, caecum, ascending and transverse colon = superior mesenteric artery and vain

descending and sigmoid colon = inferior artery and vein

superior part of the rectum = superior rectal artery and vein

6

nerve supply of colon

midgut :
SNS = superior mesenteric ganglia and lesser splanchnic nerve
PNS = vagus nerve

hind gut
SNS = inferior mesenteric ganglia and lumbar splanchnic nerve
PNS = pelvic splanchnic nerve

7

histology of large intestine

goblet cells that produce mucous; helps to transport solid content
few absorptive cells (enterocytes) and villi than SI
has straight glands

8

Rectum

begins at S3 and is bout 12 cm long
peritoneum covers the anterior and lateral walls of the superior 1/3 of the rectum
remainder of the rectum is retroperitoneal

9

transverse folds of rectum

support the weight of the rectal content and lessen the urge for defecation

10

border between the rectum and anal canal

anorectal line (upper level of the pelvic diaphragm

11

line that divides the upper and lower anal canal

pectinate (dentate) line

12

upper anal canal

gut derivative (endoderm) and is covered by simple columnar epithelium

13

lower anal canal

ectodermal derivative, covered by stratified squamous epithelium

14

bloodd supply of the rectum

superior part of the rectum (hindgut) = superior rectal artery (branch of inferior mesenteric artery)

lower part of the rectum develop from the cloaca = middle and inferior rectal arteries (branches of bilateral internal iliac arteries

15

endocrine glands of pancrea

pancreatic islets = islets of langerhans

16

liver secretion

produces bile and drains the bile via bile duct into the mucousal surface of the duodenum

17

pancreas secretion

produces digestive pancreatic juice and drains the juice via pancreatic duct into the duodenum

18

liver function

produces and stores bile, plasma proteins, and anticoagulant substances
is involved in a variety of metabolic activities of nutrients
detoxifies harmful agents

19

falciform ligament

attaches the liver to the anterior abdominal wall

splits cranially into right and left coronary ligaments

20

round ligament

previous umbilical vein is located at the caudal margin of falciform ligament

21

covering of liver

visceral peritoneum = intraperitoneal

22

coronary ligament of liver

formed at the reflection site of the visceral peritoneum fro the liver to the diaphragm
completely surrounds the bare area

23

four lobes of the liver

right lobe, left lobe, caudate lobe and quadrate lobe

24

what separates the caudate and quadrate lobe?

porta hepatis

25

where is gall bladder located?

between quadrate and right lobe

26

what is the ports hepatis?

attachment site of the lesser momentum

blood vessels and nerves enter into the liver via ports hepatis

27

lesser omentum

spans between the liver and the lesser curvature of the stomach (hepatogastric ligament)
spans between the liver and the duodenum (hepatoduodenal ligament

28

hepatoduodenal ligament

hepatic triad
contains the bile duct, portal vein and hepatic artery proper

29

fetal circulation of liver

has ductus venosus of umbilical vein and umbilical vein so that umbilical blood can bypass the liver

umbilical vein becomes the ligamentum teres
ductus venous becomes ligamentum venosum

30

where does liver receive its blood supply from?

portal vein = oxygen poor and nutrient rich from the intestines

hepatic artery proper from cell trunk
= oxygen rich

31

gall bladder function

stores concentrated bile
has a cystic duct with spiral valve

32

blood supply to the gall bladder

cystic artery in the cystohepatic triangle of calot

33

histology of liver

venous blood from portal vein and arterial blood from hepatic artery mix at the liver capillaries (sinusoids)
direction of blood flow and bile flow are inverse

34

liver lobe

hexagonal shape
functional unit of the liver
separated from other lobules by connective tissue
composed of hepatocyte plates, a central vein and liver sinusoids

35

perisinusoidal space

(Disse)
portal triads contain a vein, artery and bile duct
kupffer cells (macrophages) are found in liver sinusoids
space between liver cells and sinusoids are filled with blood plasma that has leaked from the sinusoids
contain stellate cells that store fat and vitamin A

36

Pancreas features

retroperitoneal
pancreatic enzymes
pancreatic juice also contains sodium bicarbonate which neutralised the stomach acid present in chyme
hormones insulin and glucagon regulate blood glucose levels and are secreted into the blood stream to enter hepatic portal system

37

five parts of pancreas

uncinate process, head, neck, body and tail

38

pancreatic ducts

major pancreatic duct runs the entire length of pancreas, joins bile duct at major duodenal papilla

accessory pancreatic duct enters the duodenum separately into minor duodenal papillae

39

histology of the pancrea

acinus = exocrine part
islets of langerhans = endocrine part

40

origin of pancreas

2 buds
2 pancreatic duct: accessory duct and main duct

41

blood supply of the pancreas

celiac trunk
- splenic artery and gasproduodenal artery
superior mesenteric artery
- inferior gastroduodenal artery

superior and inferior pancreaticoduodenal veins

42

innervation of liver and pancrea

SNS = greater splanchnic nerves and celiac ganglia
PNS = vagus

43

venous outflow of liver

hepatic portal vein is formed by superior mesenteric and splenic veins. the inferior mesenteric vein drains into the splenic vein
hepatic portal veins drains only unpaired organs

44

portocaval anastomoses

obstruction causes portal hypertension, blood backs up through the portal system, eventually pac through the portocaval anastomoses . they are not able to cope with large amounts of blood and become congested- varicose veins

45

four collateral pathways possible in GI tract

umbilical, oesophageal, anorectal, retroperitoneal

46

daily inflow into GIT

8 litres

47

daily reabsorption though GIT

SI = 6 L
LI = 1.5L 92L enters)

48

division of the digestive system

1. digestive tract
- upper = mouth to duodenum
- lower = jejunum to anus
2. accessory digestive organs
- glands, teeth and tongue

49

four major layers of the gut tube wall

1. mucosa
- epithelial lining, lamina propria, muscularis mucosa
2. submucosa
3. muscular externa
- circular inner layer
- long. outer layer
4. series

50

mesenteries of the foregut vs midgut and hindgut

foregut = ventral and dorsal mesenteries
midgut and handgun = dorsal mesentery only

51

cranial foregut

between oropharyngeal membrane and lung bud
formed by the pharyngeal arches and gives rise to the pharynx

52

caudal foregut

from the lung bud to the liver bud
thoracic part become the trachea, lung and oesophagus
abdominal part forms the stomach, superior duodenum, liver, gall bladder and pancreas

53

midgut

from the liveried to the 1/3rd of transverse colon

54

esophagus

attached with the hypo pharynx at the level of C6 to with stomach at T10

55

structure of the topography of the esophagus

longitudinal folds

56

three oesophageal constrictions

cricoid cartilage- C6
bifurcation of the trachea- T4
diaphragm at oesophageal hiatus T10

57

microstructure of the esophagus

stratified squamous epithelium
oesophageal glands secrete lubricant
muscular externa = upper 1/3 is skeletal, lower 2/3 is smooth muscle
lacks serosa- adventitia instead

58

oesophageal veins

cervical - inferior thyroid veins
thoracic- azygous and hemiazygous veins
abdominal part- left gastric veins

59

nerve supply of esophagus

intramural- submucosal and myenteric plexus
PNS- vagus nerves
SNS- sympathetic chain

60

achalasia

motor disorder of the oesophagus characterised by absence of peristalsis and impaired relaxation of the lower oesophageal sphincter

61

four parts of the stomach

cardia, funds, body and pyloric region

62

chemical digestion in the stomach

via acids and enzymes- Hcl and pepsin
little absorption of nutrients

63

greater and lesser omentum

lesser- attaches at the lesser curvature to the liver
greater- attache tot eh greater curvature and pancreas

64

cells in stomach wall

parietal cells- produce Hcl
chief cells- produce pepsin
surface mucous cells produce mucous

65

morphogenesis of the stomach

ventral wall and mesentery grows slower giving rise to lesser curvature
dorsal wall grows faster giving rise to the greater curvature
stomach rates around its axis 90o clockwise
left stomach becomes ventral surface supplied by left vagus nerve
right stomach becomes dorsal surface supplied by right vagus nerve

66

what does the falciform ligament contain?

umbilical vein that becomes the ligamentum teres

67

what foes the lesser omentum contain?

vessels of the liver- portal triad

68

what does the gastrosplenic ligament contain?

blood vessels of the stomach that branch from splenic vessels

69

what does the splenorenal ligament contain?

splenic artery and vein

70

what 4 ligaments does the spleen divide the dorsal mesogastrium into?

gastrophrenic,
gastrosplenic, splenorenal and greater omentum

71

artery supply of stomach

left gastric artery from celiac trunk
right gastric artery from hepatic artery proper
left gastro-mental artery from the splenic artery
right gastro-mental artery from the gastro-duodenal artery

72

supply of the funds of stomach

from th short and posterior gastric arteries, branches of the splenic arteries

73

venous drainage of the stomach

left and right gastric vein, left and right gastro-mental veins

74

gastric innervation

intrinsic- submucosal and myenteries
PNS- vagus nerves
sympathetic- greater splanchnic nerves

75

4 parts of duodenum

superior, descending, horiztonal and ascending

76

function of duodenum

neutralises acids of chyme from stomach

77

superior duodenum ligament

hepatoduodenal ligament

78

duodenojejunal flexure

where duodenum is continuous with the jejunum
supported by the ligament of treitz

79

ligament of treitz

fold containing the suspensory muscle of the duodenum

80

blood supply of the duodenum

celiac trunk- Branches of the gasproduodenal artery :superior pancreaticoduodenal artery
superior mesenteric artery: inferior pancreaticoduodenal artery

81

drainage of the duodenum

superior and inferior pancreaticoduodenal veins

82

ileum

has meckels diverticulum which is located in the distal ileum, around 60-100cm oral wards from the ileocecal valves
has peters patches in the terminal ileum

83

functional anatomy of the SI

has circular folds- valves of kerckring
has finger like intestinal villi
contains microvilli

84

circular folds

plicae circulars
increase SA and slow the passage of food
duplications of the mucous membrane
unlike the folds in the stomachs and LI they are permanent structures
appear more prominently in the duodenum and jejunum

85

microvilli

mucosa cells- lined by goblet and enterocytes
mikrovilli- located on the luminal surface of the enterocytes
lacteals- terminal lymphatic vessels in villi and transport fat metabolites and glucose whereas blood vessels in villi transport protein metabolites

86

density of veins in the GIT

most dense in the SI ---> LI ---> stomach

87

histology of SI

goblet cells
enterocytes
paneth cells
lymph nodes

88

paneth cells

located in crypts and are part of mucosal defence system

89

lymph nodules

located in mucosa for purposes of defence

90

enterocytes

most abundant cells in SI and LI
absorptive cells and contain microvilli on their apical surface

91

muscles of the anterolateral and posetior abdomen

anterolateral:
internal oblique, external oblique, transversus abdominus and rectus abdominus
posterior: posts major and minor, quadrates lumborum and ilacus

92

rectus sheath

contains anterior and posterior lamina

below the arcuate line there is no posterior lamina

93

between the rectus abdominis

tendinous intersections

94

umbilical folds

median umbilical fold contains the remanent of the urachus

medial umbilical fold contains the remnants of the umbilical arteries

lateral umbilical folds contain the inferior epigastric vessels

95

three types of peritoneal folds

1. mesenteries- planar double layered fold of peritoneum that provide physical attachment to organs that are suspended into body cavities
omen- double layered fold of peritoneum, have a net-like structure and connect the stomach to other organs
ligaments- frequently connect organs with eachother; hence each momentum can be divided into several ligaments

96

lesser sac

superior wall: diaphragm and caudate lobe of liver
anterior wall= lesser momentum, posterior wall of stomach, anterior part of greater momentum
posterior wall= posterior part of greater momentum, transverse mesocolon, pancreas
left wall= spleen
right wall = liver and epiploic foramen

97

greater sac

extends from the diaphragm down to its lowest part in the pelvis (douglas pouch)

98

how do the greater and lesser sac communicate

through the mental foramen

99

fusion of different layers of the dorsal mesentery

the mental bursa decreases in size because the greater omentum fuses

100

supramesocolic compartment

contains the upper digestive organs
transverse mesocolon is the boundary

101

inframesocoloic compartment

contains the lower digestive organs

102

recesses within the supramesocolic compartment

subphrenic space- gap between the diaphragm and liver, divided by the falciform ligament
sub hepatic space - gap between the liver and right kidney

103

gutters

right parabolic gutter freely cominucates with the right supramesocolic spaces

phrenjicocolic ligament forms a partial barrier between the left parabolic gutter and the left supramesocolic space

104

movement of fluid within the inframesocolic spaces

within the right inframesocolic space is restricted inferiorly by the ileocaecal junction
fluid in the larger left inframesocolic space can flow into the pelvic cavity