A&P Quiz 8 (Ch 24 pt 2)

Oral Cavity

mouth, lined by nonkeratinized stratified squamous epithelium

2 Regions of Oral Cavity

vestibule

oral cavity proper

Vestibule

space between the lips/cheeks and teeth

Oral Cavity Proper

space medial to the teeth

Lips (Labia)

form anterior boundary of the vestibule, important for mastication and speech, formed by the orbicularis oris muscle and connective tissue, outer skin is not highly keratinized making it more transparent

Labial Frenulum

central mucosal fold that attaches each lip to the gingiva within the vestibule

Cheeks

form the lateral walls of the oral cavity, lined with nonkeratinized stratified squamous epithelium and covered by skin

Buccinator Muscle

flattens cheek against the teeth

Buccal Fat Pad

act as a gliding pad for muscles of mastication

Palate

forms the roof of the oral cavity to prevent food from passing into the nasal cavity during chewing and swallowing

2 Regions of Palate

hard

soft

Hard Palate

anterior bony portion

Soft Palate

posterior nonbony portion composed of skeletal muscle and connective tissue

Uvula

posterior projection of the soft palate

Fauces

posterior boundary of the oral cavity, opening to the pharynx, palatine tonsils are located on the lateral wall

Tongue

large muscular organ, occupies most of the oral cavity proper when the mouth is closed

3 Features of Tongue

terminal sulcus

body

root

Terminal Sulcus

divides the tongue into the body and root

Body of Tongue

anterior portion found in the oral cavity, relatively free except at the attachment to the lingual frenulum, covered by nonkeratinized stratified squamous epithelium and papillae

Root of Tongue

posterior portion in the oropharynx, contains a few scattered taste buds and the lingual tonsil

2 Muscle Groups of Tongue

intrinsic

extrinsic

Intrinsic Tongue Muscles

within the tongue itself, responsible for the changing shape of the tongue (flattening, elevating)

Extrinsic Tongue Muscles

outside the tongue but attached to it, protrude and retract the tongue, move the tongue from side to side, change the tongues shape

5 Functions of the Tongue

moves the food in the mouth

hold food in place during mastication

major role in swallowing

location of taste buds

functions in speech

Teeth

dentition, function in mastication of food and assist in speech, 32 permanent (secondary) teeth that are in 2 dental arches (maxillary arch and mandibular arch)

Permanent Teeth

32, secondary, replace deciduous teeth staring at about 6 until 11 years, divided into four quadrants

Deciduous Teeth

primary, milk, lost during childhood, erupt between 6 months and 24 months of age

4 Quadrants of Permanent Teeth

right upper

left upper

right lower

left lower

Each Quadrant of Permanent Teeth Contains

one central and one lateral incisor

one canine

first and second premolars

first, second and third molars

3 Main Regions of Teeth

crown

neck

root

Crown

region of tooth exposed in the oral cavity and covered with enamel, can have one or more cusps

Neck

small region of tooth between crown and root

Root

largest region of tooth that anchors it to the bone

4 Structures of Teeth

pulp cavity

dentin

enamel

cementum

Pulp Cavity of Tooth

region in the center of the neck and root of the tooth, contains pulp, includes root canal and apical foramen

Tooth Pulp

collection of blood vessels, nerves, and connective tissue

Root Canal

portion of pulp cavity within root

Apical Foramen of Tooth

opening that allows nerves and blood vessels to enter and exit the pulp

Dentin of Tooth

living, cellular, calcified tissue that surrounds the root canal

Enamel of Tooth

hard, nonliving, acellular substance covering the dentin of the tooth crown, protects from abrasion and acids produced by bacteria in the mouth

Cementum of Tooth

bonelike structure that covers the surface of the dentin in the root, helps anchor the tooth to the periodontal ligament

3 Connective Structures of Tooth

alveoli (sockets)

gingiva

periodontal ligaments

Alveoli (Sockets) of Tooth

anchor site along the alveolar process of the mandible and maxilla

Gingiva of Tooth

dense fibrous connective tissue and stratified squamous epithelium covering the alveolar process

Periodontal Ligaments of Tooth

secure the teeth in the alveoli

Mastication

chewing of food by the teeth, anterior teeth (incisors and canines) primarily cut and tear food, posterior teeth (premolars and molars) crush and grind food, breaks down large food particles to increase surface area

4 Muscles of Mastication

temporalis m

masseter m

medial pterygoid m

lateral pterygoid m

Temporalis m Role in Mastication

closes jaw, retracts jaw

Masseter & Medial Pterygoid m Role in Mastication

closes jaw, protraction and lateral and medial excursion of the jaw

Lateral Pterygoid m Role in Mastication

opens jaw, protraction and lateral and medial excursion of the jaw

Mastication (Chewing) Reflex

integrated in the medulla oblongata, controls basic movements of chewing, stimulated by activation of presence of food in the mouth (relaxes muscles), muscles are stretched as mandible is lowered (activates a reflex that causes muscles of mastication to contract), descending pathways from cerebrum influence the mastication reflex to allow conscious control of chewing

Salivary Glands

scattered throughout the oral cavity, major salivary glands are compound (branching) acinar glands, can produce thin serous secretions or thicker mucous secretions

Saliva (simple)

combination from various salivary glands

2 Sizes of Salivary Glands

three pairs of large, multicellular glands

many small, coiled, tubular salivary glands

3 Pairs of Large Salivary Glands

parotid

submadibular

sublingual

4 Small Coiled Salivary Glands

lingual

palatine

buccal

labial

Lingual Glands

deep to the epithelium of the tongue

Palatine Glands

in the palate

Buccal Glands

in the cheeks

Labial Glands

in the lips

Parotid Glands

largest, located anterior to the ears, contain serous glands that secrete mostly watery saliva, includes parotid duct

Parotid Duct

exits the gland on its anterior margin, crosses the lateral surface of the masseter muscle, pierces the buccinator muscle, enters oral cavity adjacent to the second upper molar

Submandibular Glands

mixed glands, more serous then mucous acini, felt as a soft lump along the inferior border of the posterior half of the mandible, submandibular duct exits

Submandibular Duct

exits each submandibular gland, passes anteriorly deep to the mucous membrane on the floor of the oral cavity, opens into the oral cavity beside the frenulum of the tongue

Sublingual Glands

smallest of the paired salivary glands, mixed glands (contain mostly mucous acini), lie immediately below the mucous membrane in the floor of the oral cavity, have multiple openings (10-12 ducts) into the floor of the oral cavity

Saliva

composed of fluid and proteins, 1-1.5 L/day, three main roles

2 Portions of Saliva

serous

mucous

Serous Portion of Saliva

provides moisten function, produced by parotid and submandibular glands

Mucous Portion of Saliva

contains mucin that provides lubrication, produced by submandibular and sublingual glands

3 Main Roles of Saliva

helps keep oral cavity moist (important for normal speech and tasting food)

protective function

begins the process of digestion

Protective Function of Saliva

large volume of saliva continually wash oral surface, bicarbonate ions act as a buffer to neutralize acids produced by the oral bacteria and protect tooth enamel, contains lysosome (weak antibacterial action), and immunoglobulin A (helps prevent bacterial infection), mucous in saliva helps protect digestive tract from physical irritation and enzymatic digestion

Digestive Function of Saliva

relatively minor, salivary amylase, lingual lipase

Salivary Amylase

digestive enzyme that breaks bonds betwee glucose molecules in starch and other polysaccharides to produce disaccharides (maltose and isomaltose), contributes to the sweet taste of sugar, only about 2-5% of total carbs are digested here

Why is such a small amount of carbohydrate digested in the mouth?

limited amount of time in the oral cavity, cellulose covering of plants products (most starchy foods)

Lingual Lipase

digest small amount of lipid digestion

Regulation of Salivary Glands is Stimulated By

stimulated by both parasympathetic and sympathetic nervous systems, parasympathetic stimulation is more prevalent

Nerves Involved in Regulation of Salivary Glands

salivary nuclei in brainstem increases salivary secretion via parasympathetic fibers of facial (vii) and glossopharyngeal (ix) nerves, stimulated by tactile stimulation in oral cavity and certain tastes (sour)

More Regulation of Salivary Glands

can be affected by higher centers of the brain, odors can trigger thoughts of food or sensations of hunger can stimulate saliva secretion

Swallowing: Pharynx

three parts but only two normally transmit food

Nasopharynx Role in Swallowing

not a normal passageway for food

Oropharynx Role in Swallowing

superior opening to nasopharynx, inferior opening to laryngopharynx, anterior opening to posterior larynx

Laryngopharynx Role in Swallowing

extends from oropharynx to esophagus posterior to larynx

Oro & Laryngopharynx Role in Swallowing

lined with nonkeratinized stratified squamous epithelium, three muscles in posterior wall (superior, middle, and inferior pharyngeal constrictors that are arranged stacked inside each other)

Swallowing: Esophagus

extends between pharynx and stomach, 25 cm long, has the four tunics, upper esophageal sphincter and lower esophageal sphincter regulate movement of materials into and out of the esophagus, lined with nonkeratinized stratified squamous epithelium, many mucous glands in submucosal layer that secrete thick lubricating mucus

Esophageal Hiatus

opening of the diaphragm

Modifications of Esophageal Muscularis

superior 1/3 contains skeletal muscle fibers

middle 1/3 contains a mixture of skeletal and smooth muscle

inferior 1/3 contain smooth muscle fibers

3 Phases of Swallowing

voluntary

pharyngeal

esophageal

Voluntary Phase of Swallowing

first phase, bolus of food formed in oral cavity, tongue pushes against hard palate and moves toward and into oropharynx

Pharyngeal Phase of Swallowing

involuntary, 1-2 seconds, reflex initiated by stimulation of tactile receptors in oropharynx, soft palate and pharynx elevates, pharyngeal constrictor muscles contract moving food down, upper esophageal sphincter realxes

Sensory Movement in Pharyngeal Swallowing Phase

action potentials travel trigeminal (v) and glossopharyngeal (ix) nerves to swallowing center in medulla oblongata

Motor Movement in Pharyngeal Swallowing Phase

carried via trigeminal (v), glossopharyngeal (ix), vagus (x), and accessory (xi) nerves to the soft palate and pharynx

Esophageal Phase of Swallowing

5-8 seconds, responsible for moving food from pharynx to stomach, peristaltic waves of contraction, gravity assists with liquids and watery food, bolus approaches the stomach and the lower esophageal sphincter relaxes

Neural Innervation of Esophageal Phase of Swallowing

food stimulates myenteric plexus to control peristaltic waves, tactile stimuli sends impulse via the vagus nerve to the medulla oblongata, motor impulses pass along vagal efferent fiber to skeletal and smooth muscles in esophagus