HBIOANA - DIGESTIVE SYSTEM

Break

Functions of the Digestive System:
\____ down the foods you eat

nutrients

Functions of the Digestive System:
Release their \_____

orbAbs

Functions of the Digestive System:
\______ those nutrients into the body

Alimentary Canal Organs

A one-way tube about 25 feet in length that functions to nourish the body by digesting food and absorbing released nutrients

mouth, anus

Alimentary Cana Begins at the ___ and ends at the ___

pharynx, esophagus, stomach, small intestine, large intestine

What are the 5 modifications to fit the functional needs of the body? PARTS OF THE ALIMENTARY CANAL

absorption

Only through the process of \______ do the nutrients in food enter into and nourish the body's "inner space"

Peristalsis

Movement of smooth muscle in order for your food to travel through alimentary canal

Mouth

Breaks down food bolus into food particles

Esophagus

A tube used to move down food into the stomach

hydrochloric acid, acidity

Stomach produces \______ to break down food to several micromolecules and maintain \_____ in the stomach.

Accessory Structures

Sprout from the lining cells of the developing gut (mucosa) and augment its function

chemical digestion, salivary amylase

The salivary glands begin \____ by producing \______

jaundice

obstruction of pathway which causes backflow of bile, this causes \_____

Jaundice

A yellowish discoloration of mucosa which is not necessarily skin

The mucosa, submucosa, muscularis and serosa

Four tissue layers of the alimentary canal

Epithelium
Lamina propria
Muscularis mucosa

The mucosa (mucous membrane) consists of:

Epithelium

directly in contact with
ingested food

Lamina propria

a layer of connective
tissue analogous to the dermis

Muscularis mucosa

a thin, smooth muscle layer; also known as gastrointestinal tract

non-keratinized, stratified
squamous

In the mouth, pharynx, esophagus, and anal canal is primary a \__________ epithelium

simple columnar

In the stomach and intestines is a \______ epithelium

Goblet cells

○ Interspersed among its epithelial cells
○ Secrete mucus and fluid into the lumen

Enteroendocrine cells

Secrete hormones into the interstitial spaces between cells

preserve the alimentary canal

Rapidly renewed to help \_______ despite the wear and tear

lumen

The epithelium is in direct contact with the \_____

lamina propria

● consist of loose connective tissue
● Contains numerous blood and lymphatic vessels that transport nutrients absorbed through the alimentary canal to the other parts of the body

mucosa-associated
lymphoid tissue (MALT)

Serves an immune function by housing clusters of lymphocytes, making up the \_______

Peyer's patches

○ Lymphocyte clusters in the distal ileum
○ Defense against foodborne bacteria and
other foreign matter

Muscularis Mucosa

Thin layer of smooth muscle in a constant state of tension, pulling the mucosa of the stomach and small intestine into undulating folds

Rugae

folds found inside the stomach

Villi

folds found inside your small intestine

increase the surface

These folds \______ are available for digestion and absorption

Submucosa

● Lies immediately beneath the mucosa
● A broad layer of dense connective tissue
● Includes blood and lymphatic vessels, and a
scattering of submucosal glands that release digestive secretions

submucosal plexus

Serves as a conduit for a dense branching network of nerves, the \_______

Muscularis Externa

The \_________ can be found in the small intestine, mouth, pharynx, anterior part of the esophagus, and the food along the canal, stomach, and colon

an inner circular layer and an outer longitudinal layer

The small intestine is made up of a double layer of smooth muscle:

mechanical digestion

The contractions of these layers promote \__________, and move the food along the canal

skeletal, voluntary control

For the mouth, pharynx, anterior part of esophagus, and food along the canal:
Made up of \_____ muscle which allows \______ over swallowing and defecation

churning action

For the stomach:
it has a third layer (oblique muscle) equipped for its \_______

two, tenia coli

For the colon:
○ Has \____ layers like the small intestine
○ But its longitudinal layer is segregated into three narrow parallel bands (the \______)

Serosa

● Superficial to the muscularis
● Consist of a layer of visceral peritoneum overlying a layer of loose connective tissue
● Serve to hold the alimentary canal in place of collagen fibers

Adventitia

dense sheath of collagen fibers in the mouth, pharynx, and esophagus instead of serosa

Enteric nervous system

○ Intrinsic innervations of the alimentary canal
○ Runs from esophagus to the anus

Myenteric plexus and submucosal plexus

Enteric neurons are grouped into two plexuses:

Myenteric plexus

(plexus of auerbach)
■ Lies in the muscularis layer of the alimentary canal

motility

■Responsible for \_____, especially the rhythm and force of the contractions of the muscularis

submucosal plexus

(plexus of Meissner)
■ Lies in the submucosal layer

digestive secretions, food

Responsible for regulating
\_____ and reacting to the presence of \____

Autonomic nervous system

○ Extrinsic innervations of the alimentary canal
○ Includes both sympathetic and parasympathetic nerves

Sympathetic activation

\________ restricts the activity of enteric neurons

Parasympathetic activation

\________ increases GI secretion and motility by stimulating neurons of the enteric nervous ustem

transport, mucosal cells, lumen

First function is to \_____ the protein and carbohydrate nutrients absorbed by \_____ after food is digested in the \____

lacteals

Lipids are absorbed via \______, tiny structures of the lymphatic system

nutrients and oxygen, cellular processes

Second function is to supply the organs of the alimentary canal with the \_____ and \____ needed to drive their \________

aortic arch and thoracic
aorta

Anterior part of the alimentary canal: Supplied by \_____ and \______

abdominal aorta

Posterior part of alimentary tract: Supplied by \_______

The celiac trunk

Supply the liver, stomach, and duodenum

The superior and inferior mesenteric arteries

Supply the remaining small and large intestines

Hepatic portal system

○ Drains the veins that collect nutrient-rich blood from the small intestine
○ Carries that venous blood to the liver for processing

The portal vein

Formed by the union of the splenic vein
and the superior mesenteric vein

Peritoneum

A broad serous membranous sac made up of squamous epithelial tissue surrounded by connective tissue

abdominal cavity

Hold the digestive organs within the \____ in place

Parietal peritoneum

lines the abdominal wall

Visceral peritoneum

envelops the abdominal organ

The peritoneal cavity

The space bounded by the visceral and parietal peritoneal surfaces

Pleural fluid

act as a lubricant to minimize friction between the serosal surfaces of the peritoneum

Visceral peritoneum

Large folds that envelope various abdominal organs, holding them to the dorsal surface of the body wall

mesentery

attaches the small
intestine to the body wall, a fibrous connective tissue that holds abdominal organs in place

Omentum

has fibrous tissue and fat which covers your small and large intestine

adipose, fibrous

Their difference is that omentum has \____ tissue while in mesentery is purely \_____ tissue

mesocolon

the portion of the mesentery serving the colon

Oral cavity

Framed by the cheeks, tongue, and palate

Lips or labia

○ The entrance to the mouth
○ The outer skin covering transitions to a mucous membrane in the mouth proper
○ Cover the orbicularis oris muscle

Labial frenulum

A midline fold of mucous membrane that attaches the inner surface of each lip to the gum

Cheeks

Make up the oral cavity; sidewalls

non-keratinized, stratified squamous

The inner covering made up of \_____ epithelium

connective tissue, buccinator muscles

○ Between the skin and mucous membranes
are \____ and \____

Uvula

Fleshy tissue that drops down from the center of the posterior edge of the soft palate

upward, nasal cavity

The uvula moves \____ during swallowing to help keep foods and liquid from entering the \_____

palatoglossal arch and palatopharyngeal arch

Two muscular folds extend downward from the soft palate, on either side of the uvula

palatine

The \____ tonsils are located between these two arches

lingual

The \____ tonsils are located at the base of the tongue

tongue

Facilitate ingestion, mechanical digestion, chemical digestion (lingual lipase), sensation (of taste, texture, and temperature of food), swallowing, and vocalization

mandible, the styloid process of the temporal bones, and the hyoid bone

The tongue is attached to the:

oral cavity

The tongue is positioned over the floor of the \_____

medial septum

A \_______ extends the entire length of the
tongue, dividing it into symmetrical halves

The intrinsic muscles (within the tongue)

○ The longitudinalis inferior, longitudinalis superior, transversus linguae, and
verticalis linguae muscles
○ Allow change of the size and shape of the
tongue, as well as to stick it out

Extrinsic muscles of the tongue

○ Mylohyoid, hyoglossus, styloglossus, and genioglossus muscles
○ Originate outside the tongue and insert into connective tissues within the tongue

Papillae

extensions of lamina propria of the mucosa, which are covered in stratified squamous

Fungiform papillae

Mushroom shaped, cover a large area of the tongue; they tend to be larger toward the rear end of the tongue and smaller on the tip and sides

Circumvallate papillae

Only 8 to 12 in number and lie in a row along the posterior portion of the tongue anterior to the lingual tonsil

Foliate papillae

Clustered into two groups positioned on each side of the tongue

Filiform papillae

○ Long and thin papillae creating an abrasive surface
○ Have touch receptors that help the tongue move the food around in the mouth

Lingual glands

Located in the lamina propria of the tongue

lingual lipase

Secrete mucus and a watery serous fluid that contains the enzyme \_____

Lingual frenulum

A fold of mucous membranes on the underside of the tongue, that holds the tongue to the floor of the mouth

Ankyloglossia

a congenital anomaly also known by the non-medical term (tongue tie)

Salivary Glands

● Housed within the mucous membranes of the mouth and tongue
● Constantly secreting saliva, either directly into the oral cavity or indirectly through ducts

●the labial glands in the lips
●the buccal glands in the cheeks
●palatal glands in the palate
●lingual glands in the tongue

Small amounts of saliva are also secreted by these four glands: