Digestive System II Flashcards
largest cavity in the body
Abdominal cavity
- Extends from the diaphragm to the pelvis
- Abdominal cavity
ABDOMEN
*Boundaries of the Abdomen
Cranially
diaphragm
*Boundaries of the Abdomen
Dorsally
lumbar vertebrae
sublumbar muscles
crura of the diaphragm
*Boundaries of the Abdomen
Bilaterally
abdominal muscles
*Boundaries of the Abdomen
Ventrally
R&L rectus abdominis
*Boundaries of the Abdomen
Caudally
it communicates with the pelvic cavity at the pelvic inlet
*openings in the diaphragm
– Passage for the esophagus, vagal nerve trunks & esophageal vessels
Esophageal hiatus
*openings in the diaphragm
– Passage of caudal vena cava
Caval foramen
*openings in the diaphragm
– Passage for the aorta, thoracic duct, azygos vein and hemiazygos vein
Aortic hiatus
3 abdominal openings
- Umbilical aperture
- Inguinal canal
- Vascular canal
– external pudendal a. & v.
– genitofemoral nerve
– spermatic cord (male) or vaginal process (female)
Inguinal canal
- the passage to the femoral vessels, lymph node, and femoral branch of the genitofemoral nerve
Vascular lacunae
• A closed cavity & almost non-existent
• No organs or tissues are found here, except for a little fluid
• is a potential space between the parietal peritoneum (the peritoneum that surrounds the abdominal wall) and visceral peritoneum (the peritoneum that surrounds the internal organs).
Peritoneal cavity
- Serous membrane lining the abdominal cavity
- Reduces friction of adjacent organs
Peritoneum
*CLASSIFICATIONS of peritoneum (4)
- Parietal
- Visceral
- Connecting
- Retroperitoneal
*CLASSIFICATIONS of peritoneum
– mesentery, omentum, ligament
Connecting
*CLASSIFICATIONS of peritoneum
*Connecting
mesogastrium
Mesentery of the stomach
*CLASSIFICATIONS of peritoneum
*Connecting
mesoduodenum
Mesentery of the duodenum
*CLASSIFICATIONS of peritoneum
*Connecting
mesocolon
Mesentery of the colon
- Lacy apron that extends from the stomach as far as the urinary bladder
- Covers intestinal coils ventrally
Greater Omentum
4 parts of Greater Omentum
– Supercifial or ventral layer
– Deep or dorsal layer
– Omental bursa
– Epiploic foramen
- Extends from the lesser curvature of the stomach to the duodenum and liver
Lesser Omentum
*Lesser Omentum
– Liver to the duodenum =
hepatoduodenal ligament
*Lesser Omentum
– Liver to the stomach =
hepatogastric ligament
Functions of the Omentum
- Protects the organs it covers
- For holding and isolating of foreign materials
- The greater omentum is used by surgeons to vascularize tissues which have impaired blood supply
- C-shaped musculoglandular organ situated between the esophagus and the intestine
- Highly elastic and can adjust its size to the volume of its content
Stomach
- Storage and mixing of food (partial digestion)
- Production of enzymes, mucus & hydrochloric acid by its numerous glands
Stomach
Regions of the Stomach
- Cardia or stomach inlet (cardiac sphincter)
- Fundus
- Body
- Pylorus or stomach inlet (pyloric sphincter)
Curvatures of the Stomach
- Greater curvature
- Lesser curvature
Layers of the Stomach wall (microscopic)
- Tunica serosa or serous coat
- Tunica muscularis or muscular coat
- Tunica submucosa
- Tunica mucosa or mucous coat
- provide the stomach with increased surface area for nutrient absorption
- Folds stretch outward when food enters stomach
Plica gastricae / Gastric folds / Gastric rugae
Glands of the Stomach
- Gastric glands proper or fundic glands
- Cardiac glands
- Pyloric glands
*Blood supply to the Stomach
Main arteries:
L&R gastric arteries (lesser curvature)
L&R gastroepiploicarteries (greater curvature)
*Blood supply to the Stomach
Blood supply from the stomach enters the liver via the
portal vein
Nerve supply (1)
Vagus Nerve (CN X)
- Longest portion of the alimentary canal
Small Intestine
3 main parts of the small intestine
- Duodenum – short proximal loop
- Jejunum – long distal portion; freely movable
- Ileum- very short terminal part
Functions of Small Intestine (2)
- Serves for mechanical digestion and absorption
- Transport of intestinal contents and undigestible material
- First and most fixed part of the SI
- Has openings for pancreatic and bile ducts
Duodenum
4 Portions of the Duodenum:
- Cranial portion
- Descending
- Transverse
- Ascending
- Most mobile and free part of the entire alimentary canal
- Great mesentery of the jejunum or mesojejunoileum
JEJUNUM AND ILEUM
_____ is connected to the ascending colon via the ileocolic orifice
Ileum
*Blood Supply
supplied by jejunal arteries which are branches of cranial mesenteric arteries
Jejunum
*Blood Supply
duodenal branches of cranial and caudal pancreatico duodenal arteries
Duodenum
*Blood Supply
– its mesenteric side is supplied by a branch of accessory cecal artery
– antimesenteric side is supplied by ileal branch of ileocecocolic artery
Ileum
- For dehydration of its fecal contents
- For excretion of waste materials or feces
Large Intestine
Parts of the large intestine
- Cecum
- Colon
- Rectum
- No direct communication with ileum; but has an opening to the ascending colon via the cecocolic orifice (cecocolic sphincter)
Cecum
- Ascending, transverse, descending
- Right colic flexure & left colic flexure
- Descending duodenum is the largest segment of the colon
- Mesocolon – mesentery of the colon
Colon
An important feature of the rectal mucosa is the presence of around 100 solitary lymph nodules and goblet cells
Rectum
Terminal portion of the alimentary canal
Anal Canal / Anus
Special muscles of the rectum & anal canal (4)
- Internal Anal Sphincter
- External Anal Sphincter
- Pars Analis of the retractor penis (clitoridis) muscle
- Rectococcygeal muscle
A well developed band of smooth muscle inserted on the anal canal to retract the anus.
Pars Analis of the retractor penis (clitoridis) muscle
stabilizes the anal canal & rectum; prevents it from being pulled cranially by a peristaltic wave & it contracts during defecation to move the anal canal & rectum caudally
- Rectococcygeal muscle
Area surrounding the anus, bounded dorsally by the tail, ventrally by the scrotum or vulva
Perineum
