Unit 4: Concept I: Digestive System (GI Tract & Accessory Organs)

Coronary Ligament

-From Superior Surface of Liver to diaphragm -At Margins of bare

Describe the three surface features that identify the large intestine

1.) Tenia Coli: Thin, distinct longitudinal bundles of smooth muscle fibers 2.) Haustra: Sacs formed as a result of Tenia Coli causing Large Intestine to bunch up 3.) Omental Appendices: Lobules of fat hanging off of haustra

What are the general functions of the liver?

A. PRODUCE BILE: Emulsifies fats during chemical digestion B. DETOXIFIES DRUGS, metabolites and poisons from blood C. STORES excess nutrients and vitamins D.) Synthesizes blood PLASMA PROTEIN E.) REMOVES DEBRIS from blood and recycles worn out blood cells

Name all RETROPERITONEAL organs or organ segments in the digestive system

A.) Most of Duodenum B.) Pancreas C.) Ascending Colon D.) Descending Colon E.) Rectum

Name all INTRAPERITONEAL organs or organ segments in the digestive system

A.) Stomach B.) Part of Duodenum C.) Jejunum D.) Ileum E.) Cecum F.) Appendix G.) Transverse Colon

Describe the function of the rugae in the stomach

Allows stomach to expand when full and return to normal when empty

Define Intraperitoneal Organs

An organ that pushes into abdominal cavity. Suspended by peritoneal reflections: Permits Movements & Blood Vessels to pass; Completely surrounded by visceral peritoneum

Define Retroperitoneal Organ

Between parietal peritoneum and posterior wall. No Visceral Peritoneum,

Name the semifluid product that exits the stomach

Chyme

Laryngopharynx

Conducts air, passage for food and drink to esophagus

Lesser Omentum

Connection between the lesser curvature of the stomach

Greater Omentum

Connection the Greater Curvature of Stomach & Transverse Colon. Hangs down like an apron anterior to much of the digestive tract

Describe the ileocecal valve

Controls entry of materials into cecum of large intestine

Hindgut

Digestive Organs Formed: Distal 1/3 Transverse Colon, Descending Colon, Sigmoid Colon, Rectum, Superior Anal Canal Branch: Inferior Mesenteric Artery Autonomic Nerve Plexus: -Sympathetic Nerves: L1-L2 -Parasympathetic Nerves: Pelvic Splanchnic Nerves (S2-S4)

Foregut

Digestive Organs Formed: Pharynx, Esophagus, Stomach, Proximal Duodenum Accessory Organs Formed: Liver, Gallbladder, Biliary Tree, Pancreas Branch: Celiac Trunk/Aorta Autonomic Nerve Plexus: -Sympathetic Nerve: T5-T9 -Parasympathetic Nerve: Vagus Nerve (CN X)

Midgut

Digestive Organs Formed: distal duodenum, jejunum, ileum, cecum, appendix, ascending colon, proximal 2/3 of transverse colon Branch: Superior Mesenteric Artery Autonomic Nerve Plexus: -Sympathetic Nerves: T8-T12 -Parasympathetic Nerves: Vagus Nerve (CN X)

What is mesentary?

Double-layer reflection of peritoneum formed as an organ pushed into abdominal cavity, wrapping itself visceral peritoneum

Compare the external

Internal- Involuntary Smooth Muscle External-Voluntary Skeletal Muscle Both: Close off opening to anal canal and relax during defecation

What is the function of bile?

It assists in the digestion and absorption of fats, and it is responsible for the elimination of certain waste products from the body, particularly hemoglobin from destroyed red blood cells and excess cholesterol

Describe the components and connection of the biliary tree

Left & Right Hepatic Ducts to Common Hepatic Duct Cystic Duct & Common Hepatic to Bile Duct Pancreatic Duct to Bile Duct

Describe the two ducts of the pancreas

Main: Joins bile duct & drains digestive enzymes from pancreas into duodenum Accessory: Drains into duodenum superior/proximal to main pancreatic duct

What is unique about the muscularis of the stomach and how does this help with the function of the stomach?

Muscularis= 3 layers of smooth muscle -Longitudinal, Circular, & Oblique -Allows for churning/blending of contents

Nasopharynx

Posterior to Nasal Cavity; Conducts Air

Oropharynx

Posterior to oral cavity conducts air, passageway for food and drink

What is the function of the pyloric sphincter

Regulating entrance of chyme into duodenum

Describe the embryological significance of the ligamentum teres hapatis

Remnant of fetal umbilical vein

What are the general functions of the pancreas?

Secrets pancreatic juices

What is the function of the gallbladder?

Stores & concentrates bile produced by the liver until needed for digestion

Describe the anatomical relationship between the duodenum and pancreas

The pancreas is superior to the duodenum

Define Peritoneum

The serous membrane that line the abdominopelvic wall and many organs.

Describe the peritoneal cavity and its content

The spaces between: parietal (lines cavity) & visceral (lines organs) Peritoneum: Allows for movement and expansion of organs that are filled with serous fluid.

Describe the function of the esophagus

Transport swallowed materials from pharynx to stomach

Describe the way in which the abdominal cavity is divided into 4 quadrants. Name the quadrants

Transverse & Midsagittal Planes intersection @ the umbilicus form: Left & Right Upper; Left & Right Lower

List the general functions of the digestive system

a.) Ingestion- Solid & Liquid materials enter oral cavity b.) Digestion- Break down materials into smaller structures & molecules c.) Propulsion- Materials swallowed & move through GI Tract d.) Secretion- Release of fluids to aid in digestion and protection of GI tract e.) Absorption- Digestion products, water, vitamins, and electrolytes move from GI tract into blood or lymph f.) elimination of water

Describe the 4 layers/tunics of the wall of the GI Tract

a.) Mucosa (deepest-in contact w/ lumen) b.) Submucosa c.) Muscularis d.) Adventitia or Serosa (Superficial, Outer Layer) Serosa- covered by visceral peritoneum on intraperitoneal organs Adventitia- On retroperitoneal organs

Name the organs of the GI tract (alimentary tract)

a.) Oral Cavity b.) Pharynx c.) Esophagus d.) Stomach e.) Large Intestine f.) Small Intestine g.) Anus

Name the accessory digestive organs

a.) Parotid Salivary Gland b.) Teeth c.) tongue d.) Sublingual Salivary Gland e.) Submandibular Salivary Gland f.) Liver g.) Gallbladder h.) Pancreas

Sigmoid Mesocolon

From Abdominal Wall to Sigmoid Colon

Mesentery Proper

From Abdominal Wall to Small Intestine

Transverse Mesocolon

From Abdominal Wall to Transverse Colon

Falciform Ligament

From Liver to Anterior Abdominal Wall