Unit 17 - Digestive System #1 Flashcards
Not everything we eat is used by the body, such as cellulose and fiber.
These materials must be expelled from the body via a process called _____
“defecation”.
The digestive system is composed of two separate categories of organs.
The digestive organs and accessory digestive organs
The ______collectively make up the “gastrointestinal (GI) tract” or “alimentary (Latin for “relating to nourishment”) canal”.
digestive organs
1) The GI tract organs include:
(a) Oral cavity
(b) Pharynx
(c) Esophagus
(d) Stomach
(e) Small intestine
(f) Large intestine
The ______ do not form the long GI tube, but often develop as outgrowths from and are connected to the GI tract.
accessory digestive organs
1) The accessory digestive organs include:
(a) Teeth
(b) Tongue
(c) Salivary glands
(d) Liver
(e) Gallbladder
(f) Pancreas
The digestive system performs six main functions.
- Ingestion
- Digestion
- Propulsion
- Secretion
- Absorption
- Elimination
the introduction of solid and liquid nutrients into the oral cavity.
Ingestion
The breakdown of large food items into smaller structures and molecules.
Digestion
Two types of digestion
Mechanical Digestion & Chemical Digestion
physically breaks down ingested materials into smaller pieces.
Mechanical Digestion
The first part of mechanical digestion is ______”, the chewing of ingested food by the teeth in the oral cavity.
Mastication
breaks down ingested molecules into smaller molecules by using enzymes.
Chemical Digestion
After the materials are swallowed, they move through the GI tract in a process termed ______
“propulsion”
There are two types of movements involved in propulsion.
Peristalsis & Segmentation
the process of muscular contraction
that forms ripples along part of the GI tract (much like pushing toothpaste out of a
tube) and causes material to move further along the tract
Peristalsis
is churning and mixing movements in the small intestine which help dispense the material being digested and combine it with intestinal secretions
Segmentation
the process of producing and releasing fluid products, such as acid, bile, digestive enzymes, and mucin
Secretion
When these fluids are secreted into the lumen of the GI tract, they facilitate chemical digestion and the passage of materials through the GI tract.
involves either passive movement or active transport of electrolytes, digestion products, vitamins, and water across the GI tract epithelium and into GI tract blood and lymphatic vessels.
Absorption
the final function of the digestive system.
Elimination
All undigestible materials as well as the waste products secreted by the accessory organs into the GI tract are compacted into ______, or fecal material, and then eliminated from the GI tract by the process of “defecation”
“feces”
The _____, or mouth, is the entrance to the GI tract.
“oral cavity”
The _____ is the initial site of mechanical digestion (via mastication) and chemical digestion (via an enzyme in the saliva).
mouth
The mouth is lined with ______ that protects against the abrasive activities associated with digestion.
stratified epithelium
This lining is continually moistened by the secretion of saliva.
The floor, or inferior surface, of the oral cavity contains the tongue as well as muscles covered with mucosa.
True
The oral cavity has two distinct regions:
1) The “vestibule” is the space between the cheeks or lips and the gums.
(a) This is where persons who chew tobacco hold the material after chewing.
2) The “oral cavity proper” lies central to the alveolar processes of the mandible and maxillae.
The “lips” have a reddish hue because of their abundant supply of superficial blood vessels and the reduced amount of _____ within their outer skin.
keratin
The ______ or “gums” are composed of dense regular connective tissue, with an overlying stratified epithelium that covers the alveolar processes of the upper and lower jaws and surrounds the necks of the teeth.
“gingivae”
The internal surfaces of the superior and inferior lips each are attached to the gingivae by a thin mucosal fold in the midline, called the ______
“labial frenulum”
The _____ forms the roof of the oral cavity and acts as a barrier to separate it from the nasal cavity.
“palate”
The _____, which makes up the anterior two-thirds, is formed by the palatine processes of the maxillae and the horizontal plates of the palatine bones.
“hard palate”
The Hard Palate exhibits prominent ______, to assist the tongue in manipulating ingested materials prior to swallowing.
“transverse palatine folds” or “friction ridges”
The arching _____ is primarily composed of skeletal muscle.
“soft palate”
Extending inferiorly from the posterior part of the soft palate is a conical projection called the ____
“uvula”
When you swallow, the soft palate and the uvula elevate to close off the posterior entrance to the nasopharynx and prevent ingested materials from entering the nasal region.
The _____ are located toward the posterior lateral portions of the oral cavity and serve as an early line of defense as they monitor ingested food and drink for antigens.
palatine tonsils
They can initiate an immune response when necessary.
In addition, the tongue manipulates and mixes ingested materials during chewing and helps compress the partially digested materials against the hard palate to turn these materials into a _____, a globular mass of partially digested material.
“bolus”
The inferior surface of the tongue attaches to the floor of the oral cavity by a thin vertical mucous membrane, the _____
“lingual frenulum”
The salivary glands collectively produce and secrete ______, a fluid that assists in the initial activities of digestion or to keep the mouth moist.
“saliva”
The volume of saliva secreted daily ranges between _____.
1.0 and 1.5 liters
The salivary enzyme _____ begins chemical digestion by breaking down starch.
“amylase”
Saliva contains antibodies and an antibacterial substance called _____ that helps inhibit bacterial growth in the oral cavity.
“lysozyme”
It is a watery medium into which food molecules are dissolved so taste receptors can be stimulated.
Saliva
_____ pairs of multicellular salivary glands are located external to the oral cavity
What are they
Three
“parotid salivary glands”, “submandibular salivary glands”, “sublingual salivary glands”
the largest salivary glands.
“parotid salivary glands”
This gland becomes infected and swollen with mumps.
“parotid salivary glands”
Each _____ is located anterior and inferior to the ear, partially overlying the masseter muscle.
parotid gland
The “parotid duct”, which carries the saliva to the oral cavity, travels parallel to the _____ and opens into the vestibule of the oral cavity near the second upper molar
zygomatic arch
salivary glands that are inferior to the body of the mandible.
“submandibular salivary glands”
A “submandibular duct” opens from each gland in the floor of the mouth on the lateral sides of the _____.
These are the squirters used in “gleeking”!
lingual frenulum
The “______ glands” are inferior to the tongue and internal to the oral cavity mucosa.
sublingual salivary
Each sublingual salivary gland extends multiple tiny sublingual ducts that open onto the inferior surface of the oral cavity.
True
The salivary glands are primarily innervated by the _____ division of the autonomic nervous system.
parasympathetic
In particular, the ______ innervates the submandibular and sublingual glands, while the ______ innervates the parotid glands.
facial nerve (CN VII), glossopharyngeal nerve (CN IX)