(Slides 1-8) Digestive overview, peristalsis, segmentation, & GI tract

What are the two groups of organs that make up the digestive system?

• Alimentary Canal organs/ Gastrointestinal (GI) tract organs

• Accessory structures

What organs make up the alimentary Canal organs/ Gastrointestinal (GI) tract of the digestive system?

• Mouth

• Pharynx

• Esophagus

• Stomach

• Small Intestine

• Large Intestine (colon)

• Rectum

• Anus

What organs make up the accessory structures of the digestive system?

• Teeth

• Tongue

• Salivary Glands

• Liver

• Gallbladder

• Pancreas

What is the purpose of the alimentary Canal organs/ Gastrointestinal (GI) tract of the digestive system?

Continous tube that nourishes the body

• has two opening to the outside world

What is the purpose of the accessory structures of the digestive system?

Facilitates Digestion

What are three salivary glands?

• Parotid Glands

• Sublingual Glands

• Submandibular Glands

What body system provides this benefit to the digestive system:

• Blood supplies digestive organs with oxygen and processed nutrients

Cardiovascular System

What body system provides this benefit to the digestive system:

• Hormones help regulate secretion in digestive glands and accessory organs

Endocrine System

What body system provides this benefit to the digestive system:

• Skin helps protect digestive organs and synthesizes vitamin D for calcium absorption

Integumentary System

What body system provides this benefit to the digestive system:

• Mucosa-associated lymphoid tissue and other lymphatic tissue defend against entry of pathogens; lacteals absorb lipids; and lymphatic vessels transport lipids to bloodstream

Lymphatic System

What body system provides this benefit to the digestive system:

• Skeletal muscles support and protect abdominal organs

Muscular System

What body system provides this benefit to the digestive system:

• Sensory and motor neurons help regulate secretions and muscle contractions in the digestive tract

Nervous System

What body system provides this benefit to the digestive system:

• Respiratory organs provide oxygen and remove carbon dioxide

Respiratory System

What body system provides this benefit to the digestive system:

• Bones help protect and support digestive organs

Skeletal System

What body system provides this benefit to the digestive system:

• Kidneys convert vitamin D into its active form, allowing calcium absorption in the small intestine

Urinary System

What are the processes of the digestive system? How many are they?

Six

• Ingestion

• Propulsion

• Mechanical Digestion

• Chemical Digestion

• Absorption

• Defecation

What digestion process is being described:

• Taking food or liquid into the mouth; eating or drinking.

Ingestion

What digestion process is being described:

• Moving food forward through the GI tract by:

  • swallowing (oropharynx)

  • involuntary peristaltic waves (esophagus, stomach, small intestine, large intestine)

Propulsion

What digestion process is being described:

• Physical breakdown of food:

  • chewing in the mouth

  • churning in the stomach

  • segmentation in the small intestine.

Mechanical digestion

What digestion process is being described:

• Enzymatic breakdown of food into its chemical building blocks.

Chemical Digestion

What digestion process is being described:

• Movement of nutrients and water into blood and lymph vessels in the small intestine

• Water absorption in the large intestine.

Absorption

What digestion process is being described:

• Elimination of indigestible material as feces through the anus.

Defecation

Where does chemical and mechanical digestion begin?

The mouth

• through mastication and salivary amylase

What are the two muscle layers that are in every organ of the digestive system?

• Inner circular

• Outer longitudinal muscle layers

What are alternating contraction sequence of both the inner circular and outer longitudinal muscle layers?

Peristalsis

What are localized contractions of the circular muscle layer facilitate the blending of materials by back-and-forth movements of material?

Segmentation/Mixing

What digestive process is a voluntary action?

Ingestion

Propulsion

• Swallowing

Defecation

• External sphincter Muscles

What digestive process is an involuntary action?

Propulsion

• Peristalsis

Mechanical Digestions

Chemical Digestion

Absorption

Defecation

• Internal sphincter Muscles

What are the four basic tissue layers of the Alimentary canal/GI tract

• Mucosa

• Submucosa

• Muscularis

• Serosa

What is commonly called as the mesentery of the digestive system?

Two layers of serous membrane

• Pariteal Peritoneum

• Visceral Peritoneum

What is located between the muscularis and submucosa layer of the GI tract and innervates the mucosa and submucosa (supplies those areas with nerves)?

Submucosal Plexus

• Plexus of meissner

What is located between the two muscles (inner circular and outer longitudinal muscle layers) of the muscularis layer in the GI tract and innervates them (supplies those areas with nerves)?

Myenteric Plexus

Why does the mucosa have the muscularis mucosae layer?

Our GI tracts have digestive glands that secrete enzyme and other stuff. In order to release this content to the lumen the muscularis mucosae layer must contract.

What are the different epithelium in our digestive system?

Simple Columnar

Stratified Squamous

What areas of our digestive system have Simple Columnar Epithelium?

• Stomach

• Small intestine (duodenum, jejunum, ileum)

• Large intestine (colon + rectum)

What areas of our digestive system have Stratified Squamous Epithelium?

• Mouth

• Oropharynx

• Laryngopharynx

• Esophagus

• Anal canal (distal end)

• Rectum

Why are these areas lined with stratified squamous epithelium:

• Mouth

• Oropharynx

• Laryngopharynx

• Esophagus

• Anal canal (distal end)

• Rectum

Because these areas need to be protected because they are subjected to abrasions

What are the parts of the mucosa layer of the GI tract?

- Epithelium

- Lamina propria

- Muscularis mucosae

What is the lamina propria of the mucosa layer of the GI tract made of and have?

• Areolar Connective Tissue

• MALT: Lymphatic Nodules

  • If any pathogen in our food crosses the epithelium, it must go through lymphatic nodules

What is the muscularis mucosae of the mucosa layer of the GI tract made of and have?

• Narrow band of smooth muscle

• Elastic Fibers

What are the parts of the submucosa layer of the GI tract?

- Areolar Connective Tissue

-Dense irregular Connective Tissue

- Blood & lymphatic vessels

- Submucosal plexus

What are the parts of the muscularis layer of the GI tract?

- Circular muscle (Inner layer)

- Longitudinal muscle (Outer Layer)

- Myenteric plexus

What are the parts of the serosa/adventia layer of the GI tract?

- Areolar Connective Tissue

-Collagen

-Elastic fibers

Whether or not the outer layer of the GI tract contains serosa or Adventia depends on?

The location on GI tract

• Serosa: Intraperitoneal

• Adventitia: Retroperitoneal

If the outer most layer of the area of the GI tract is made of serosa, it must be?

Intraperitoneal

• Small Intestine

• Large Intestine (Transverse & Sigmoid)

• Gallbladder

• Liver

If the outer most layer of the area of the GI tract is made of Adventitia, it must be?

Retroperitoneal

• Duodenum

• Pancreas

• Colon (ascending and descending)

• Esophagus (abdominal portion)

• Rectum

The GI tract has its own nervous system called the?

Enteric Nervous System (ENS)

What best describes the enteric nervous system (ENS)?

• The “brain of the gut”

• The second brain

• Working independently

• Intrinsic set of nerves

• Has two primary plexuses

  • Submucosal Plexus

  • Myenteric Plexus

What best describes the automatic nervous system (ANS)?

• Extrinsic set of nerves

• Parasympathetic

  • increases secretion and motility (By stimulating ENS)

• Sympathetic

  • Decreases secretion and motility (By inhibiting ENS)

What does the sympathetic stimulation of the Automatic nervous system do to the digestive system?

Decreases secretion and motility

• by inhibiting ENS

• fight or flight

What does the parasympathetic stimulation of the Automatic nervous system do to the digestive system?

Increases secretion and motility

• By stimulating ENS

• Rest and digest

85% or more of serotonin is released by our?

Gut Microbiota

The enteric nervous system works independently from the?

Central Nervous system

What plexus of the enteric nervous system controls secretions and muscular contractions?

Submucosal Plexus

What plexus of the enteric nervous system is in charge of GI tract mobility and peristalsis?

Myenteric Plexus

What is the connection between the enteric nervous systtem and our central nervous system?

Automatic Nervous system

What are the neural innervations of the gut?

• Enteric Nervous System (ENS)

• Autonomic Nervous System (ANS)

What is the ability of an organism, cell, or fluid to move independently and spontaneously using metabolic energy?

Motility