L9 - DIGESTIVE SYSTEM

Quadrants and Regions of the Abdomen:

  • Four Q (RU< LU< RL< LL)

  • 9 regions of the abdomen (starting from the midclavicular lines, subcostal “transpyloric” plane - L1, and transtubercular plane - L5 = like a tic tac toe board)

    • from top left to bottom right: right hypocondriac region, epigastric region, left hypochondriac region, right lumbar region, umbillical region, left lumbar region, right inguinal region, suprapubic region, left inguinal region

The Anterior abdominal wall:

common function for all three layers: flexion, rotation of trunk, compression of abdominal contents, assists in expiration

  1. external oblique muscle, fiber orientation: ant/inferior

  2. internal oblique muscle, fiber orientation: ant/superior

  3. transversus abdominis muscle, fiber orientation: horizontal/transverse

Lina Alba (LA) is central attachment of all aponeruoses along the midline, tendinous intersections is the lines in between the abs, Linea semilunari: transition of skeltal muscle tissue into its aponeurrosis = lateral borders of the rectus abdomins muscle

rectus abdominis: compression of abdominal contents and flexion of vertebral column

surface anatomy of the abdomen:

layers of the rectus sheath

(above the umbilicus)

  • layers pos to rectus abdominis

    • pariental peritoneum, transversalis fascia, apon of transversus abdominis, ½ apon of internal oblique

  • layers ant to rectus abdomins

    • ½ apon of internal oblqie, apon of external oblique, scarpa fascia, camper fascia, skin

organization of the peritoneum:

parietal peritoneum is outer layer, visceral perit is inner, and mesentery is the line: suspends IP organs, contains vascular structures

IP organs (intraperitoneal) = surrounded by visceral peritoneum

retroperitoneal organs = sit behind the parietal peritoneum

organ systems of the abdomen:

the digestive system, gallbladder and liver, renal/urinary sys, biliary and pancreatic sys (accessory organs), teeth, tongue

pharynx - muscular pharnyx that will utilize peristalis to direct food from the oral cavity into the esophagus

soft palate - elevation during swallowing depression during chewing

epiglottis - cartilaginous structure within the larynx covered in mucosal epithelium that acts as a barrier to prevent food/drink from getting into our airways

adduction of the vocal folds to close off the rima glottidis - depression of epiglottis to close off laryngeal inlet

muscles help depress the epiglottis during swallowing

the process of deglutition (swallowing)

3 phases

  1. oral phase: movement of tongue in ant to pos seq against palate

    • initation = voluntary control

  2. pharyngeal phase: closure of nasal and laryngeal cavities via soft palate and epiglottis respectively

    • invol control

  3. esophageal phase: coordination of muscle contraction to propel the bolus inferiorly to the stomach (peristalsis)

  • invol control

divisions of the digestive tract:

foregut = esophagus (abdominal) to the D3/4 seg (liver, gall, pan, spleen)

hindgut = distal 1/3 transverse colon to the rectum

midgut = D4, jejunum, proximal 2/3 transverse colon

the foregut; the esophagus

no digestion happening, movement of food via peristalis to the stomach

the foregut; stomach

is intraperitoneal and involve both chem and mech digestion

the small intestine: duodenum

peristalsys, chem digest, absorp

blood supply of the abdomen:

celiac trunk

foregut: eso, stomach, D1 - 3/4, liv, pan, gall, spleen

superior mesenteric artery

midgut

inferior mesenteric artery

hindgut