Introduction
➢ Other names are: Alimentary & Digestive system
▪ The function of this system is to receive, digest and absorb food & includes the following components:
Mouth, Pharynx, Esophagus, Stomach, small & large Intestine, Rectum, Anal canal, Liver and Pancreas.
➢ It has an area of about 320 m2(four times the size of a tennis court) and a length of about 7 to 10 m
➢ Transit time from the mouth to the anus is about 24 to 72 hours
➢ The wall of the alimentary canal consists of four layers:
Mucus, Submucous, Muscular layer & Connective tissue
➢ The majority of the this system is located inside the abdominal cavity.
Mouth & pharynx
▪ Mouth is the first part to get and start digesting food and consists of two parts: vestibule and proper oral cavity.
The mouth connects to the pharynx through the fauces.
▪ Pharynx or throat is a common way for
respiratory and digestive tracts which extends
from skull base to 6th cervical vertebra.
▪ And consists of three parts :- Nasopharynx, Oropharynx and Laryngopharynx.
➢ Mouth & pharynx are fully explained in the
topic of head and neck anatomy
Abdominal cavity
▪ It is the largest cavity in the human body that is enclosed by the vertebral column and abdominal wall (posterior & anterolateral walls)
➢ In addition to most of the gastrointestinal tract, abdomen contains the spleen, kidneys and adrenal glands
➢ In this section, in addition to the abdominal wall, inguinal region and inguinal canal, the coverage of the inner surface of the abdominal cavity, i.e. peritoneum, is also studied.
The cavity can be divided into two parts:
1) Larger upper & anterior part is abdominal cavity proper.
2) Smaller lower & posterior part, called the true pelvis.
Inlet separates true abdominal & true pelvis cavities.
The abdominal cavity has roof, floor, anterolateral and posterior walls.
I. The roof is formed by the diaphragm
II. The floor by the upper surface of the pelvic diaphragm
III. Anterior & lateral wall mainly consists of by the antero- lateral muscles
IV. Posterior wall is formed by the posterior abdominal muscles
Abdominal cavity contents
▪ The tracts that are located in the abdominal cavity and in the true pelvic cavity are:
I. Gastrointestinal tract
End part of the esophagus, stomach, duodenum, jejunum, ileum, colon, liver, and pancreas are located in the abdominal cavity, while the rectum and anal canal are located in the true pelvis
II. Urinary tract
The kidneys and half of the ureters are in the abdominal cavity but the bladder and part of the urethra are in the true pelvic cavity.
III. Reproductive tract
In women, the gonads (ovaries), fallopian tubes, uterus and vagina are all located in the true pelvis.
In men, the gonads (testicles) outside the abdominal cavity, the genital tract is located in the true pelvic cavity, And
IV. Vessels & nerves
Aorta, vena cava inferior, portal vein and its branches.
Lumbar plexus and Sympathetic chain.
