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45 terms

Chapter 15 - Digestion

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digestion
refers to the mechanical and chemical breakdown of foods so that nutrients can be absorbed by cells.
alimentary canal
a muscular tube about 9 meters long that passes through the body's ventral cavity.
mucosa
the inner layer of the alimentary canal which is lined with epithelium attached to connective tissue; it protects tissues of the canal and carries on secretion and absorption.
submucosa
the next layer of the alimentary canal made up of loose connective tissue housing blood and lymph vessels and nerves; it nourishes the surrounding layers of the canal.
muscular layer
consists of inner circular fibers and outer longitudinal fibers that propel food through the canal.
serosa
the outer layer composed of visceral peritoneum that protects underlying tissues and secretes serous fluid to keep the canal from sticking to other tissues in the abdominal cavity.
mixing movements and propelling movements
the motor functions of the alimentary canal are of two types
mixing movements
occur when smooth muscles contract rhythmically in small sections of the tube.
propelling movements
include a wavelike motion called peristalsis, which is caused by contraction behind a mass of food as relaxation allows the mass to enter the next segment of the tube.
mouth
the first portion of the alimentary canal; it functions to receive food and begins mechanical digestion by mastication.
Cheeks
form the lateral walls of the mouth.
lips
highly mobile structures that surround the mouth opening; contain sensory receptors that help to judge the temperature and texture of food.
tongue
a thick, muscular organ covered by mucous membrane with taste buds within papillae; it is attached to the floor of the mouth by the frenulum.
papillae
provide friction for moving food around in the mouth.
Lingual tonsils
lymphatic tissues located at the root of the tongue.
palate
forms the roof of the oral cavity and has an anterior hard palate and posterior soft palate.
soft palate and uvula
function to close off the nasal cavity during swallowing.
palatine tonsils
associated with the palate in the back of the mouth; because they are lymphatic tissue, help to protect the body against infection.
pharyngeal tonsils
(adenoids), another lymphatic tissue; located on the posterior wall of the pharynx, above the border of the soft palate.
two
How many sets of teeth develop in sockets within the alveolar processes of the maxillary and mandibular bones?
20, 32
The _____ primary teeth are shed in the order they appeared and are replaced by _____ secondary teeth.
mechanical digestion
Through the actions of chewing, teeth break food into smaller pieces, beginning ________.
periodontal ligament
A tooth is held tight in its socket by a ________.
incisors
very front teeth, used for biting into something
cuspids
next to incisors/ little sharp ones
bicuspids
next to cuspids/ called premolars/ usually pulled by dentist if has to
molars
great big teeth in the back used for crushing
wisdom teeth
not everyone has a third set of teeth called ________
crown
the part of the tooth that you can see
enamel
the crown has an outer layer called _____
root
the part of the tooth that you can't see
periodontisis
when the actual membrane that holds the tooth becomes inflamed and starts losing bone and teeth are loosening
cavity
bacteria in your mouth carries this
acid
when bacterial metabolize, they produce _____ and wear away the tooth enamel
saliva
what the salivary gland secretes; moistens and dissolves food particles, binds them together, allows tasting, helps to cleanse the mouth and teeth, and begins carbohydrate digestion.
parotid gland
largest of salivary glands; thin and watery/ used primarily when you need to digest
sublingual gland
under the tongue; very small and this salvia is the thick and the stringy kind
submandibular gland
thicker; located on the floor of the mouth, secrete a more viscous fluid.
serous
Salivary glands contain _____ cells that produce a watery fluid with amylase, and mucous cells that produce lubricating and binding mucus.
parasympathetic stimulation
Salivary glands receive _____ that triggers the production of a large volume of saliva at the sight or smell of food.
parotid glands
lying in front of the ear, are the largest of the major salivary glands; they secrete a clear, watery fluid rich in amylase.
sublingual glands
inferior to the tongue, are the smallest of the major salivary glands and secrete a saliva that is thick and stringy.
pharynx
a cavity lying behind the mouth
esophagus
a muscular tube leading to the stomach
nasopharynx, oropharynx, largyngopharynx
The pharynx connects the nasal and oral cavities with the larynx and esophagus and is divided into three portions: