Anatomy and Physiology Chapter 24

Food contains what

It contains substances and energy the body needs to construct all cell components.

Food must be broken down through what?

Through the digestion to molecular size before it can be absorbed by the digestive system and used by the cells. The organs that collectively perform these functions compose the digestive system.

What is Gastroenterology

The study of the structures, functions, and disorders of the digestive tract for the upper end of the system

What is Proctology

The study of the structures, functions and disorders of the digestive tract for the lower end of the system.

Function of the Mouth

Bite, chew, swallow

Function of the Pharynx and esophagus

transport

Function of the stomach

Mechanical disruption; absorption of water and alcohol

Function of the small intestine

chemical and mechanical digestion and absorption

Function of the Large Intestine

Absorbs electrolytes and vitamins (B and K)

Function of Rectum and Anus

Defecation

The two major sections of the digestive system perform what

Peform the process required to prepare food for use in the body

What is the Gastrointestinal tract

It is the tube open at both ends for transit of food during processing

What are the functional segments of the GI Tract

Include the mouth, esophagus, stomach, small intestine, and large intestine

Accessory Structures contribute to what?

Contributes to the food processing include the teeth, tongue, salivary glands, liver, gallbladder, and pancreas

Digestion includes how many processes

6 basic processes

What is ingestion

Is taking the food into the mouth (eating)

What is secretion

Is the release, by cells within the walls of the GI tract and accessory organs, of water, acid, buffers, and enzymes into the lumen of the tract.

What does mixing and Propulsion result from

It results from the alternating contraction and relaxation of the smooth muscles within the walls of the GI tract.

What does Mechanical digestion consists of

It consists of movements of the GI tract that aid chemical digestion

What is Chemical digestion

It is the series of catabolic (hydrolysis) reaction that break down large carbohydrate, lipid, and protein food molecules into small molecules that are usable by body cells.

Absorption is the passage of what

It is the passage of end products of digestion from the GI tract into blood or lymph for distribution to cells.

What is Defecation

it is the emptying of the rectum, eliminating indigestible substances from the GI tract

What are the basic arrangement of layers in the gastrointestinal tract

from the inside outward includes the mucosa, submucosa, muscularis, and serosa

Layers of the GI tract

1. Mucosal layer
2. Submucosal layer
3. Muscularis layer
4. Serosa layer

What does the Mucosa consist of

It consist of an epithelium, lamina propria, and muscularis mucosa.

What does the epithelium of the GI tract consist of

It consists of a protective layer of non-keratinized stratified cells, simple cells for secretion and absorption, and mucus secreting cells, as well as some enteroendocrine cells that put out hormones that help regulate the digestive process

What does the lamina propria consists

it consist of three componenets, including loose connective tissue that adheres the epithelium to the lower layers, the system of blood and lymph vessels through which absorbed food is transported, and nerves and sensors.

The lymph system is part of what

It is part of the mucosa-associated lymph tissues (MALT) that monitor and produce an immune response to pathogens passing with food through the GI tract,

What does the Muscularis Mucosa cause

it causes the local folding of the mucosal layer to increase surface are digestion and absorption

Gi Tract and immune cells

It is estimated that there are as many immune cells associated with the GI tract as in all the rest of the body

Lamina Propria Anatomy

Thin layer of loose connective tissue. Contains BV and lymphatic tissue

Muscularis Mucosa does what

It causes folds to form in mucosal layer, increases local movements increasing absorption with exposure to “new” nutrients

Submucosa consists of what

it consists of the aerolar connective tissue. It is highly vascular. Contains a part of the submucosal plexus (plexus of meissner) contains glands and lymphatic tissue

The submucosal plexus is a part of what

It is a part of the autonomic nervous system. It regulates movements of the mucosa, vasoconstriction of blood vessels, and innervates secretory cells of mucosal glands

Loose connective tissue of the Submucosa

Containing BV, glands and lymphatic tissue

Meissner’s plexus of the submucosa

Parasympathetic, innervation. Vasoconstriction, local movement by muscularis mucosa smooth muscle.

Skeletal muscle in muscularis equals what

it equals voluntary control. In mouth, pharynx, upper esophagus and anus. Control over swallowing and defectation.

Smooth muscle in muscularis equals what

It equals involuntary control. Inner circular fibers and outer longitudinal fibers. Mixes, crushes and propels food along by perstalsis.

Auerbach’s plexus (Myenteric)

Both parasymphathetic and sympathetic innervation of circular and longitudinal smooth muscle layers

Serosa is an example of what

An example of a serous membrane

Serosa covers what

It covers all organs and walls of cavities not open to the outside of the body.

What does serosa secrete

It secretes slippery fluid

What does serosa consist of

It consist of connective tissue covered with simple squamous epithelium

Enteric Nervous System consist of what

Consists of neurons that extend from the esophagus to the gut. Consist of motor neurons, interneurons, and sensory neurons.

Where is the Enteric Nervous System located

It is located in the myenteric plexus and the submucosal plexus

What do Myentaric neurons control

they control gastric motility while the submucosal neurons control the secretory cells.

Enteric Nervous System can function independently of the what?

Independently of the CNS.

Vagus nerve (x) supplies what

It supplies the parasympathetic fibers. These fibers synapse with neurons in the ENS and increase their action

Sympathetic nerves arise from what

They arise from the thoracic and upper lumber regions of the spinal cord. These fibers also synapse with neurons in the ENS. However, they inhibit the ENS neurons

What do the Gastrointestinal Reflex Pathways do

They regulate secretions and motility in response to stimuli present in the lumen.

When do the reflexes of the Gastrointestinal Reflex Pathways begin

They begin with receptors associated with sensory neurons of the ENS

What is the peritoneum

Is the largest serous membrane of the body

What is the parietal Peritoneum

it lines the wall of the abdominal cavity

What is the Visceral Peritoneum

Covers some of the organs and constitutes their serosa

What is the Peritoneal Cavity

It is the potential space between the parietal and visceral portions of the peritoneum, and contains serous fluid.

Kidney and Pancreas lies where

Lies on the posterior abdominal wall behdin the peritoneum, and are called retroperitoneal

What does the peritoneum contain

It contains the large folds that weave between the viscera, functioning to support organs and to contain blood vessels, lymphatic vessels and nerves of the abdominal organs

Extensions of the peritoneum include what

Includes the mesentery, mesocolon, falciform ligament, lesser omentum, and greater omentum

Peritoneum contains what

Contains visceral layer which covers organs. Parietal layers lines the walls of body cavity

Peritoneal cavity contains what

contains potential space containing a bit of seroud fluid

Parts of the Peritoneum

Mesentery, Mesocolon, Lesser Omentum, Greater Omentum

What is Peritonitis

Inflammation, trauma, rupture of GI tract, appendicitis, perforated ulcer

What is the Cause of Peritonitis

Contamination by infectious microbes during surgery or from rupture of abdominal organs

The mouth is what

(oral or buccal cavity) is formed by the cheeks, hard and soft palate, lips and tongue

The vestibule is what

Of the oral cavity is bounded externally by the cheeks and lips and internally by the gums and teeth

The oral cavity proper is what

Is a space that extends from the gums and teeth to the fauces, the opening between the oral cavity and the pharynx or throat

Lips and cheeks contain what

Buccinator muscle that keeps food between upper and lower teeth

Vestibule is what

An area between cheeks and teeth

Oral Cavity proper

The roof=hard, soft palate and uvula, floor= the tongue

Pharygneal arches

Two skeletal muscles, Palatoglossal muscle and the palatopharyngeal muscle

What is the Palatoglossal muscle

It extends from palate to tongue, forms the first arch, posterior limit of the mouth

What is the Palatopharyngeal muscle

Extends from palate to pharyngeal wall, forms the second arch, behind the palatine tonsil

What are the salivary glands

where the major portion of saliva is secreted, which lie outside the mouth and pour their contents into ducts that empty into the oral cavity

Where does the remainder of the saliva come from

The remainder comes from buccal glands in the mucous membrane that lines the mouth

What are the three pairs of salivary glands

Parotid, submandibular (submaxillary), and sublingual glands

saliva does what

It lubricates and dissolves food and starts the chemical digestion of carbohydrates. It also functions to keep the mucous membranes of the mouth and throat moist

Chemically, what is saliva

It is 99.5% water and .5% solutes such as salts, dissolved gases, various organic substances, and enzymes

Mumps is what

An inflammation and enlargement of the parotid salivary glands cuased bu infection with the mumps virus (myovirus)

Symptoms of the mumps

Include fever, malaise, pain swelling of one or both glands.

what happens if mumps if contracted by a male past puberty

It is possible to experience inflammation of the testes and occasionally sterility

Where is the parotid gland

Below your ear and over the masseter

Where is the submandibular gland

is under the lower edge of mandible

Where is the sublingual gland

It is deep to the tongue in floor of mouth

All of the salivary glands have what

They all have ducts that empty into the oral cavity

Functions of saliva

Wet food for easier swallowing, dissolves food for tasting, bicarbonate ions buffer acidic foods. Protects mouth from infection with its rinsing action— 1 to 1 and ½ qts day

What is bulemia

Vomiting hurts the enamel on your teeth

Chemical digestion of starch begins with what

Begins with enzyme (salivary amylase)

What do enzymes do (lysozome)

helps destroy bacteria

Salivary Gland Cellular structure

• Cells in acini (clusters)
• Serous cells secrete a watery fluid
• Mucous cells (pale staining) secrete a slimy, mucus secretion

Serous cells secrete what

They secrete a watery fluid

Mucous cells (pale staining) secrete what

It secretes a slimy, mucus secretion

Ways the body increases salivation

– sight, smell, sounds, memory of food, tongue stimulation---rock in mouth
– cerebral cortex signals the salivatory nuclei in brainstem---(CN 7 & 9)
– parasympathetic nn. (CN 7 & 9)

What stops salivation

dry mouth when you are afraid, sympathetic nerves

What does the Myxovirus attack

It attacks the parotid gland

Symptons of the Myxovirus

– inflammation and enlargement of the parotid
– fever, malaise & sour throat (especially swallowing sour foods)
– swelling on one or both sides

Sterility in Mumps (Myxovirus)

Rarely possible in males with testicular involvement (only one side involved)

Vaccine of the mumps has been available since when

Since 1967

The tongue forms what

Together with its associated muscle, forms the floor of the oral cavity, It is composed of skeletael muscle covered with mucous membrane

Extrinsic and intrinsic muscles permit the tongue to be what

To be moved to participate in food manipulation for chewing and swallowing and in speech