Digestive Anatomy Flashcards
(127 cards)
1
Q
What makes up the digestive system?
A
- Digestive tract
- Accessory organs
2
Q
What are under digestive tract?
A
Mouth, teeth, pharynx, esophagus, stomach, small intestine, large intestine
3
Q
What are accessory organs?
A
- Salivary glands (parotid, sublingual and submandibular)
- Liver
- Gallbladder
- Pancreas
4
Q
What makes up the abdominal cavity?
A
- Peritoneum
- Mesenteries
- Peritoneal cavity
5
Q
What is the structure of the peritoneum?
A
- Parietal peritoneum (outer layer): lines the body wall
- Visceral peritoneum (inner layer): covers the surface layer of organ and continues with parietal
- Peritoneal cavity: filled with fluid (peritoneum fluid) allows organs to slide each other and along the body wall to function
6
Q
What are mesenteries?
A
- Double layer of peritoneum –> fused back to back –> one connects to organ, one connect to the body wall
- Fold of membrane that attaches the intestine to the abdominal wall and holds it in place
7
Q
What is dorsal mesentery?
A
- Attached to the dorsal body wall
- Dorsal: posterior part of the body (cranial + spinal)
8
Q
What is ventral mesentery?
A
- Attached to the ventral body wall
- Ventral: anterior part of body (thoracic + abdominal + pelvic)
9
Q
What are retroperitoneal organs?
A
- Lose their mesentery during development
- Mesentery reabsorbed and lost –> lie behind the peritoneum
- SAD PUCKER
o Suprarenal (adrenal) glands
o Aorta/IVC
o Duodenum (except the proximal 2 cm)
o Pancreas (except tail)
o Ureters
o Colon (ascending and descending)
o Kidneys
o Esophagus
o Rectum
10
Q
What are intraperitoneal organs?
A
- Retains their mesentery, covered by visceral peritoneum
- Stomach
- 5cm-4th part of duodenum
- Jejunum
- Ileum
- Liver
- Spleen
- Cecum
- Appendix
- Transverse and sigmoid colon
- Upper third of rectum
- (intraperitoneal organs perforates can see the contents of organs spilling into peritoneal cavity eg. perforated appendicitis)
11
Q
What are the subdivisions of peritoneum?
A
- Mesentery
- Mesocolon
- Greater Omentum
- Lesser Omentum
- Ligaments
12
Q
Describe the mesentery of small intestine
A
- Attached to the jejunum and ileum
- Double layer peritoneum
- Have blood vessels, lymphatics
- Anchors the jejunum and ileum
13
Q
What is the mesentery that covers large intestine?
A
Mesocolon
14
Q
What is a mesocolon?
A
- A mesentery joining the colon to the dorsal abdominal wall
- Parts of the transverse coon
- Eg. transverse mesocolon, sigmoid mesocolon etc
15
Q
What is the mesentery that covers stomach?
A
Omentum (2 types: greater and lesser)
16
Q
Describe the omentum
A
- Stabilize stomach in position
- Forms a root for blood vessels, nerves and lymphatics to go between the stomach
17
Q
What is the greater omentum?
A
- Attaches the stomach to transverse colon
- Attach from the greater curvature of the stomach and covers and hangs over the intestine
- Double sheet of peritoneum, folded on itself = 4 layers
18
Q
What is the lesser omentum?
A
- Attaches the stomach and duodenum to liver
- Attach from lesser curvature of the stomach
- Double layer of peritoneum
19
Q
What is the mesentery of liver?
A
- Ligaments
- Double layer folds of peritoneum
- Attach liver to surrounding organ or abdominal wall
20
Q
What are the subdivisions of peritoneal cavity?
A
- Greater peritoneal cavity
- Lesser peritoneal cavity
21
Q
What makes up the greater sac?
A
- Greater peritoneal cavity
22
Q
What makes up the lesser sac?
A
- Lesser peritoneal cavity
23
Q
What is the role of a peritoneal cavity?
A
- Divides into spaces, compartments
- Closed space –> cannot be visualize in radiology, but apparently in pathology
- Treatment for peritoneal diseases
24
Q
What is the Foramen of Winslow?
A
- Passage between the greater and lesser sac that allows communications between the sacs
25
What is the structure of an alimentary canal?
- Lumen
| - Wall layers
26
What are the wall layers of the alimentary canal?
- Mucosa, submucosa, muscularis externa, serosa
27
What are the special features of layers for the oesophagus and retroperitoneal organs?
- They have adventitia instead of serosa
| - Wall layers: mucosa, submucosa muscularis externa and adventitia
28
What makes up the mucosa layer of the alimentary canal?
- epithelium
- lamina propria
- muscularis mucosae
29
What is the type of epithelium that lines the mucosal layer of the alimentary canal?
- Epithelium (2 main types)
o Stomach to rectum: simple columnar epithelium + cells secretes mucous and enzymes
o Esophagus to anal canal: stratified squamous non-keratinized epithelium (protection + avascular)
30
What is the lamina propria of the mucosal layer of the alimentary canal?
o Under epithelium lining + loose connective tissue and capillaries for nourishment + glands + lymphatic vessels
o Presence of MALT (mucosa-associated lymphoid tissue): defense against microbes entering alimentary canal
31
What is the muscularis mucosae of the mucosal layer of the alimentary canal?
o Smooth muscle tissue + inner circular + contraction for motility of mucous membrane --> enhancing secretion
o Protects underlying layers
o Absorb digestive products
32
What makes up the muscularis externa layer of the alimentary canal?
- outer longitudinal muscle
| - inner circular muscle
33
Describe the muscularis externa layer of the alimentary canal
- Outer longitudinal muscles and inner circular muscle
o Circular: muscles in circular shape of tube (INNER)
o Longitudinal: horizontal way, straight (OUTER)
- Aka muscularis propria: external to submucosa
- Provides motility in alimentary canal
- Some inner circular muscle thickens --> form anatomical sphincters --> eg. pyloric sphincter (at stomach and duodenum) and ileocecal valve (at small and large intestine), internal anal sphincter (upper part of anal canal)
o Controls passage of nutrients or waste in GI to prevent regurgitation
- Between two muscle layers: have myenteric nerve plexus (motility of alimentary canal)
34
What makes up the serosa layer of the alimentary canal?
- Outermost layer of all intraperitoneal organs
- Contributed by visceral peritoneum
- Epithelial cells (mesothelial cells)
- Outer layers (adventitia)
o For retroperitoneal organs
o Esophagus lie in the thorax, outermost layer have adventitia
35
What are the intrinsic nerve plexus of the alimentary canal?
- Myenteric nerve plexus
| - Submucosal nerve plexus
36
What is the anatomy of the oral cavity?
- Lips are lined with mucous membrane --> buccal mucosa
- Hard palate: anterior, separates oral and nasal cavity, made up of palatine bone
- Soft palate: posterior, mobile skeletal muscles separate the oropharynx and nasopharynx
o Temporary close the opening of nasopharynx, oropharynx
o Move when swallowing, close the oropharynx
- Uvula: hangs from soft palate
- Vestibule: keep food between the teeth and help with speech
- Soft palate to tongue: palatoglossal fold/arch
- Palatopharyngeal arch
- In between these two arches/fold: palatine fold
- Aaaaa: soft palate goes up --> palatoglossal and palatopharyngeal folds
37
What makes up the tongue?
- Vascular and sensitive
- Muscular organ with interlacing bundles of skeletal muscles of intrinsic and extrinsic
- Sensory organ for taste
- Oral cavity + tongue: lined with stratified squamous non-keratinised epithelium
- Sulcus terminal
o V shape line (behind V is pharynx area, infront V is oral cavity)
o Divides tongue into anterior 2 thirds and posterior
o Separates the oral and pharynx
o Dorsal of tongue is not smooth --> aka papilla
- Papilla: bumps on the tongue, all have taste buds except for filiform papillae
- 4 kinds of papilla
- Posterior of tongue --> have lymphoid follicles
o Collection of lymphoid follicles are lingual tonsils
o Extrinsic muscles: help protrude or elevate tongue, up down in out
o Intrinsic muscles: help give shape and size changes of the tongue,
- Midline groove: anterior part --> separate the right and left tongue
38
What makes up the adult dentition?
- 32 dentitions
o 8 each side (bottom, top divide into two) (8 x 4 sides)
o 2, 1, 2, 3 (from centre to side)
- 2 incisors (central and lateral)
- 1 canine
- 2 premolar (bicuspids): first and second premolars
- 3 molar (first, second and third/wisdom)
- Pulp: contains blood vessels, nerve and connective tissue
39
What makes up the fetus dentition?
```
- 20 deciduous (milk) teeth
o 5 each side
o 2, 1, 2 (from centre to side)
- 2 incisors
- 1 canine
- 2 molars (first and second)
```
40
What are the corresponding glands and ducts in the oral cavity?
- 3 types and in pairs (left and right side)
- All are exocrine (have ducts)
- Parotid gland & parotid duct (or Stensen's duct)
o Largest
o Infront of ear
o Between the masseter muscle and skin
o Open to oral vestibule, next to second upper molar
o Facial nerve pass through parotid gland
o Diseased parotid gland facial nerve is cut facial paralysis one side
- Submandibular gland & submandibular duct
o Under jawline, under the chin
o Opens at the base of lingual frenulum
- Sublingual gland & sublingual ducts
o Under the tongue
o Opens via 10-20 ducts into the floor of mouth
o Anterior to submandibular gland
41
What are the cells present at the salivary glands?
Serous, mucous
42
What is the role of serous cells?
- produce a watery secretion containing enzymes, ions and tiny bit of mucin
43
What is the role of mucous cells?
produce mucus, stringy, vicious solution
44
What cells can be found on the parotid and submandibular glands?
mostly serous cells
45
What cells can be found on sublingual glands?
mostly mucous cells
46
What cells can be found on buccal glands (inner side of cheeks) ?
equal serous and mucous cells
47
What are the functions of the pharynx, oropharynx, and laryngopharynx?
- Pharynx: transport food to esophagus (protection of airway from aspiration of food particles)
o Connects mouth to esophagus
- Oropharynx and laryngopharynx: common passage for air, food and liquids
48
Which part of pharynx has no digestive role?
Nasopharynx
49
What are the components of the oesophagus?
- Starts at the neck --> crosses through thorax within mediastinum
- Presence of longitudinal muscles
- Pierces diaphragm at esophageal hiatus and enter abdomen and join at junction gastroesophageal or cardiac orifice
- Cardiac orifice: surrounded by a ring of smooth muscles aka Lower Esophageal Sphincter (LES) or cardiac sphincter
- LES: physiological sphincter
o Remains contracted and closed
o Opens to incoming food, or when swallow
o Both LES + muscular diaphragm helps keeps LES close when food is not swallowed
- UES: Upper Esophageal Sphincter
o Junction of pharynx, upper end of esophagus, muscularis externa modified to form UES
o Aka cricopharyngeal sphincter
o Most narrow point of the entire alimentary canal
o Made up of skeletal muscle
50
What is the histology of esophagus?
- Mucosa: lined with stratified squamous NK epithelium (eat hard food)
- Submucosa: areolar connective tissue
o Had many glands that produce mucous for the rib
```
- Muscularis externa
o Inner circular layer
o Outer longitudinal layer
o Upper 1/3: skeletal muscle
o Middle 1/3: mixed (both skeletal and smooth)
o Lower 1/3: smooth muscle
```
- Adventitia: fibrous connective tissue
51
What are the muscles in the oesophagus?
- Upper 1/3: skeletal muscle
- Middle 1/3: mixed (both skeletal and smooth)
- Lower 1/3: smooth muscle
- Skeletal: voluntary
- Smooth: involuntary
52
How is the muscalaris externa unique in the oesophagus?
- It has 3 different muscles present at each 1/3 of the esophagus
53
Are there any mucus secreting glands in the oesophagus?
- Yes, in the submucosa
| - It aids in lubrication and movement
54
Which parts of the esophagus does it narrow?
- UES
- Arch of aorta and left main bronchus
- LES, where it is passing through the diaphragm (esophageal hiatus)
55
Which salivary duct is related to the molar tooth?
- Parotid duct
56
What are the quadrants and regions of the abdomen?
- 4 quadrants
| - 9 regions
57
Where is the stomach located at?
- Under diaphragm in the left upper quadrant and epigastric region
58
What is the anatomy of the stomach?
```
- Two orifices (two openings)
o Cardiac (food goes from esophagus to stomach entry)
o Pyloric/pylorus: chyme leaving the stomach to duodenum
```
- Two sphincters
o Cardiac or lower esophageal sphincter (LES) (physiological sphincter)
o Pyloric sphincter (anatomical sphincter)
- Two curvatures
o Lesser curvature: short, concave, medial surface of stomach
o Greater curvature: long, lateral border of stomach
- Two omentum
o Are peritoneal folds attached to stomach
o Membrane thin layer from liver and continuous to the stomach
o Fold connected to lesser curvature --> lesser omentum
o Folds connected to greater curvature --> greater omentum
- Two surfaces
o Anterior surface
o Posterior surface
59
What are orifices?
- Openings of the stomach
60
What are curvature?
- Medial and lateral borders of the stomach that are curved
| - Forms lesser or greater curvature
61
What is a pyloric canal/pylorus?
- Pyloric segment of stomach that opens up to the pyloric sphincter into duodenum
- Pylorus has 3 parts
o Antrum
o Canal (narrow)
o Sphincter (valve)
62
What are the layers of muscularis externa on the stomach?
- Longitudinal layer
- Circular layer
- Oblique layer: churn food and make chyme
- Help squeeze and churn food during mechanical digestion
63
What is the body of the stomach?
- Largest part of the stomach
64
What is cardia?
- Entrance of esophagus
65
What is fundus?
- Upper part of the stomach , next to cardia
| - It stores gas produced during digestion
66
What are the layers of the stomach?
- Mucosa: inner lining of stomach
- Submucosa: outer layer that covers mucosa
- Muscularis externa
- Serosa: fibrous membrane covering outside of stomach
67
What is rugae of mucosa?
- When stomach is empty, the walls are folded into a series of ridges called rugae (stomach folds – longitudinally)
o Present in people who are fasting, absent in those who eats a lot
- When there is the consumption of food and liquids, it allows the expansion of the stomach
68
Describe the mucosa layer of the stomach
o Presence of mucous neck cells
o Surface epithelium mucous cells:
- important for production of alkaline mucous layer under which there is trapped layer of bicarbonate rich alkaline fluid --> to neutralize harsh acids
o Lamina propria
- Smooth lining of surface mucosa --> disrupted by opening --> called gastric pits
- Gastric pits leads to gastric glands (gastric glands are in the lamina propria of mucosa)
o Muscularis mucosae
69
Describe the submucosa layer of the stomach
o Contains submucosal plexus
- regulates the configuration of the luminal surface, controls glandular secretions, alters electrolyte and water transport, and regulates local blood flow.
70
Describe the muscularis externa layer of the stomach
o Contains myenteric plexus
o Longitudinal layer
o Circular layer
o Oblique layer
o Innermost --> outermost
- Oblique --> circular --> longitudinal
o Smooth muscle modification: allows stomach to churn --> food converted to chyme
71
Describe the serosa layer of the stomach
o Outer layer
| o Watery secretion: helps protect the stomach from friction as it expands with food and moves to mix and propel food
72
What is a chyme?
- Food that leaves the stomach as a soupy mixture
73
What are the types of cells of the stomach?
- Parietal cells
- Chief cells
- Enteroendocrine cells
- Mucous neck cells
- Surface mucous cells
74
What are the roles of parietal cells?
- Secretes HCl acid in the lumen of stomach
- Cellular mechanism of HCl: proton pump mechanism
- Produces intrinsic factor for absorption of vitamin B12
75
What are the roles of enteroendocrine cells?
- Secrete paracrine molecules
| - Histamine and serotonin
76
What are the roles of mucous neck cells?
- Smaller than surface mucous cells
| - Secretes acidic fluid containing mucin proteins
77
What are the roles of chief cells?
- Lie at the bottom of gastric gland -> secrete inactive precursor -> aka pepsinogen
- Pepsinogen + HCl -> pepsinogen will be converted to active form -> aka pepsin
- Secretes gastric lipase -> are pepsin secreting cells
78
What are the parts of the small intestine?
o Duodenum: c-shaped, shortest, retroperitoneal, curves around the head of pancreas, major duodenal papilla, submucosal brunner’s glands
- Major duodenal papilla: dilated junction of pancreatic duct and bile duct enter the duodenum
- Submucosal brunner’s glands: secretion of bicarbonate rich alkalin mucous -> use to neutralize acidic chyme from stomach -> help protect the intestinal wall from gastric juices
o Jejunum: 2.5m long, intraperitoneal, suspended by mesentery
o Ileum: longest (3.5m), intraperitoneal, suspended by mesentery, joins the large intestine at the ileocecal valve
79
What are the location of the small intestine?
left and right lower quadrant
80
What are the structure of the small intestine?
o Convoluted tube from pyloric sphincter to ileocecal valve
o Superior mesentery artery --> main arterial supply
81
What are the function of the small intestine?
major digestive organ, where digestion is completed (with the help of bile and pancreatic enzymes ) and virtually all absorption occurs
82
What are the parts of the large intestine?
Cecum, appendix, colon, rectum and anal canal
83
What is the cecum of the large intestine?
first part of large intestine
84
What is the appendix of the large intestine?
o masses of lymphoid tissue + MALT = important for immunity
o Structure problems: twisted --> susceptible to blockage
o related to cecum (projection at cecum)
85
What is the colon of the large intestine?
o Ascending, transverse, descending, sigmoid colons
o Ascending --> right colic (hepatic flexure) --> transverse colon
o Transverse colon --> left colic (splenic) flexure --> descending colon
o Descending colon --> enters pelvis --> S-shaped sigmoid colon
o Sigmoid colon --> joins rectum --> anal canal
86
What is the anal canal of the large intestine?
- two sphincters
o External: skeletal muscle, voluntary
o Internal: smooth muscles, involuntary
87
What is the special features of the large intestine?
teniae coli, haustra, epiploic appendages
| - Length (1.5m), diameter (6cm)
88
What is the function of the large intestine?
absorbs water and eliminates feces
89
What are the location of the large intestine?
left and right lower quadrant
90
What are plicae circulares?
- Permanent circular folds found prominently in the jejunum
91
What are the modifications for absorption in small intestine?
o Circular folds (plicae circulares)
o Villi
o Microvilli
92
What are the circular folds structure in the small intestine?
- Deep, contributed by mucosa and submucosa
- Seen with naked eye
- Folds forces to spiral through lumen
- Permanents fold (abundant in jejunum, less abundant in ileum)
- Provide huge surface area and length
93
What are villi structure of small intestine?
- Fingerlike projection of mucosa and towards lumen
- Covered by mucosa epithelium, simple columnar
- Epithelial cells are absorptive cells for absorption
- Pink coloured cells
- Goblet cells
- Between villus
o Blood capillaries and lacteal (wide lymphatic capillary)
- Digested nutrients are absorbed into blood or lymph capillary
94
What are microvilli structure of small intestine?
- Each absorptive cells and identify the extension of cellular of apical membrane
- Densely cellular extension of apical membrane --> brush border straited structure
- Includes enzymes: brush border enzymes
- Between the villus presence the intestinal glands (INTESTINAL CRYPTS)
o Crypts decrease in number along the length of small intestine
95
What are the cells of the small intestine?
- Enterocyte
- Goblet cells
- Enteroendocrine cells
- Stem cells
- Paneth cells
96
What is the role of enterocyte?
o Bulk of epithelium
o Simple columnar absorptive cell
o In villi: absorption of nutrients and electrolytes
o In crypts: secrete intestinal juice --> contains mucus and serves as a carrier fluid for absorbing nutrients from chyme
97
What is the role of goblet cell?
o Mucus-secreting cells in the crypts and villi
98
What is the role of enteroendocrine cell?
o Source for enterogastrones (secretin and cholecystoskinin)
o Mostly in crypts, some in villi
99
What is the role of stem cell?
o In depts of crypts
o Differentiate to form other cell types
o Regeneration of cell population
100
What is the role of paneth cell?
o Found deep in crypts
o Secretory cells that fortify the small intestines defense secrete anti-microbial agents (defensins and lysozyme)
101
What are teniae coli, haustrum, epiploic appendages?
- Epiploic appendages: fat filled pouches
- Haustrum: series of pouches
- Teniae coli: bands of longitudinal layer of muscularis externa forms bands of teniae
102
What is the interior of cecum?
- 2 openings: ileocecal valve and appendix
103
What are the positions of appendix?
- Most common: retrocecal (64%), pelvic (32%)
104
What is the structure of anal canal?
- Rectum: valve are transverse folds, called rectal valves (permanent folds), separates fecal materials and prevents feces from passing out along with gas
- Terminal of anal canal -> have 2 sphincters -> closed except during defecation
o Internal
- Involuntary
- By smooth muscles + autonomic
- Reflux
o External
- Voluntary
- By skeletal muscles + somatic nervous system
- Contract to close the rectum and prevent poop from coming out
- Back up
- Piles: veins elongated coming out of anus
- pectinate line: divides 2 thirds and lower third of the anal canal
105
Where is the location of the liver?
- Right hypochondric & epigastric region
| - Under the diaphragm, within the ribcage for protection
106
What are the functions of the liver?
- Filter, detoxify, process nutrients coming via the portal vein
- Blood from hepatic artery and portal vein passes through sinusoids --> flows towards the central vein
107
What are the features of the liver?
- Anatomical lobes (right and left) (defined by ligaments)
o Right lobe (largest lobe)
- Caudate
- Quadrate
- Porta hepatis (or portal triad)
o Main gateway for entry and exit
o Consists of hepatic ducts, hepatic artery, portal vein
- 2 hepatic ducts fuses and joins to form common hepatic duct
- Hepatic artery and portal vein: 2 sources for blood entry into liver
108
What is the falciform ligament?
- It divides the liver anatomically/physiologically
109
What is the ligamentum venosum?
- Ductus venosus as blood stops flowing through the umbilical vein -> converted to ligamentum venosum on liver undersurface
110
What are the physiological lobes?
- They are functional lobes
- Defined by blood supply
- Marked by a line that runs through the bed of inferior vena cava and gallbladder fossa
- Line separates the 2 physiological lobes equally
111
What is the histology of liver?
- 100000 liver lobules --> forms the basic functional units of liver
112
Describe the liver lobule?
- Hexagonal shape
- Boundaries are portal spaces (PS)/portal triad
- Has central vein in the center of the lobule
- Hepatocytes are separated by sinusoids
o Plates of liver cells -> radiate from centre towards
o Sinusoids: type of leaky capillaries
113
What makes up the portal triad?
- Bile ducts
- Portal vein
- Hepatic artery
114
What is the biliary drainage?
- Hepatic: bile secreted by hepatocytes -> flows into network of channels -> bile canaliculi -> into bile ductules -> into interlobular biliary ducts -> into right and left hepatic ducts of right and left lobes -> which unites to form common hepatic duct
- Blood flows towards central vein
o Bile produced moves in opposite direction
- Common hepatic ducts exits liver at porta hepatis
115
What forms the common hepatic duct?
- 2 hepatic ducts fuses and joins to form common hepatic duct
116
What are kuppffer cells?
- Specialized cells lining the sinusoids that can engulf particles
- To protect liver cells
- Type of macrophage -> deals with foreign particles and worn out blood cells
117
What are gall bladders? Location?
- Pear shaped organ
- Muscular sac
- Lies on the inferior surface of the liver
118
What are the roles of gall bladder?
- Concentrates bile
- Stores and releases bile
o Mediated by hormones (enterogastrone hormones)
- Converts watery bile to viscid bile
119
What is the extrahepatic biliary drainage?
- CHD exits at the porta hepatis -> joined by cystic duct on the right -> forms the common bile duct
- Bile duct -> opens into duodenum along the main pancreatic duct
- Gallbladder, cystic duct and bile duct: are extra biliary apparatus
120
Where is the pancreas located?
- Central part of the abdomen
- Posterior to the stomach
- Projects to the left
- Lies on the c-shaped duodenum
121
What are acinar cells? Location? Role?
- Lines acinar (glandular component of pancreas)
- Helps in digestion
- Highly metabolic cells: produces enzymes (proteases, amylase, lipase) -> digest 3 nutrients
- These enzymes enter the duct in inactive forms
o Linings of the duct secrete bicarbonate rich alkaline fluid
122
What is the relationship of liver, gall bladder and pancreas to duodenum?
- In pancreas: main pancreatic duct (starts at tail -> body -> head) opens at duodenum at major duodenal papilla
- At termination: pancreatic duct fuses with bile duct (point of fusion: hepatopancreatic ampulla)
- Hepatopancreatic ampulla: enclosed by sphincter of oddi
123
What is the mechanism for secretion of bile and pancreatic juice?
- Regulated by hormones
1. Chyme entering duodenum -> releases cholecystokinin (CCK) and secretin -> from duodenal enteroendocrine cells
2. CCK and secretin enter bloodstream
a. Regulate the secretion of bile and pancreatic juice
3. CCK induces secretion of enzyme rich pancreatic juice, secretin causes the secretion of HCO3- rich pancreatic juice
4. Bile salts and (less amt) secretin -> transported via bloodstream -> stimulate liver to produce bile rapidly
5. CCK -> enters bloodstream -> causes gallbladder to contract + hepatopancreatic sphincter to relax -> bile enters duodenum
6. Cephalic and gastric phases: vagal nerve stimulation -> weakens the contraction of gallbladder
124
What is the splanchnic circulation-blood supply?
- Serves the digestive system and hepatic portal system
- Includes the arteries, branches of abdominal aorta --> supplies the digestive system within the abdomen
- Blood supply to digestive system comes from 3 branches of aorta
125
What are the arteries of the splanchnic circulation?
```
- Celiac artery supplies to
o Liver
o Gallbladder
o Lower esophagus
o Stomach
o Parts of pancreas
o Duodenum
o Spleen
```
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- Superior mesenteric artery supplies to
o Remaining parts of pancreas
o Duodenum
o Jejunum
o Ileum
o Cecum
o Appendix
o Ascending and part of transverse colon
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- Inferior mesenteric artery supplies to:
o Remaining parts of transverse colon
o Descending
o Sigmoid colon & continuous at superior rectal artery to supply upper part of rectum
126
What is the dual blood supply for duodenum?
- The celiac and the superior mesenteric arteries
127
What is the hepatic portal circulation?
- A system where blood passes through 2 capillary veins before entering the general circulation
- Hepatic veins are not part of the portal system
- Liver 2nd capillary vein --> provided by sinusoids of liver
- Portal vein:
o formed by union of superior mesenteric vein and splenic vein
o drains the venous blood from abdominal part of digestive organs (LES to rectum)
o includes veins from gallbladder, pancreas and spleen
