GI and oral cavity and pharynx

Question 1

what is the gastrointestinal tract

Answer 1

a continuous tube from oral cavity to anus

Question 2

what are the gastrointestinal tract components

Answer 2

HEAD - oral cavity, pharynx
NECK - pharynx, oesophagus
THORAX - oesophagus
DIAPHRAM - stomach, small intestine, large intestine
PELVIS - rectum
PERINEUM - anal canal, anus

Question 3

what are the funtions of the GI tract

Answer 3

1. introduce food into body
2. digest and absorb nutrients and toxins
3. excrete residual waste out body

Question 4

what are the functions of each components of the GI tract

Answer 4

Oral Cavity: Sensing ,Salivation, Chewing, Initiating swallowing

Pharynx: Defence against infection (tonsils), Swallowing, Airway protection

Oesophagus: Transit from pharynx to stomach

Stomach and small intestine - Transit, Defence against infection (acid), Digestion and absorption
(accessory organs of GI tract)

Large Intestine and Anus: Transit, Reabsorption of H2O & electrolytes, Stool formation, Waste excretion

Question 5

what is mastication

Answer 5

movement of jaw and tongue to break down food and mix with saliva for taste and digestion

Question 6

what are the muscles of mastication

Answer 6

control opening and closing of mouth

Temporalis (elevates mandible)
masseter (elevates mandible)
lateral pterygoid (depresses mandible)
medial pterygoid (elevates mandible)

Question 7

describe the adult dentition

Answer 7

upper dental arch - maxillary
lower dental arch - mandibular

4 quadrants - upper right, upper left, lower right, lower left

1, 2 = incisor
3 = canine
4,5 = premolar
6,7,8 = molar
8 = wisdom tooth

32 in total

Question 8

describe the anatomy of the tongue

Answer 8

posterior one third - vertical part
anterior 2 thirds - horizontal part

Question 9

what are the muscles in the toungue used for

Answer 9

move tongue around during mastication, speech and swallowing

extrinsic muscles - four pairs which attach tongue to bony skeleton

intrinsic muscles - change shape of tongue

Question 10

what are the 7 properties of saliva

Answer 10

• 99% water
• solute to allow tasting
• contains mucin (lube) to aid - swallowing and speech and keep mucosa moist
• buffer for plaque acids
• antibacterial elements
• contains amylase for carbohydrate digestion

Question 11

what are the major and minor glands in saliva

Answer 11

major -
parotid - near ear
submandibular - under mandible
sublingual - under tongue

minor -
1000s in oral mucosa and basal secretions to keep mouth moist

Question 12

what stimulates saliva

Answer 12

thought,sights,smell of food or food in mouth
painful oral conditons like teething or fractured mandible

Question 13

where do the salivary glands MISSSING

Answer 13

submandibular gland - enters floor of mouth, secretes via sublingual caruncle

sublingual gland - located in floor of mouth, secretes via several ducts superiorly

Question 14

What occurs if ducts are blocked

Answer 14

swelling due to back up of secretions

Question 15

what are the muscles of facial expression used for

Answer 15

buccinator - tenses cheek, aligns food between teeth

orbicularis oris - circular muscles surrounding the mouth lying withing lips, prevents dribbling during chewing and swallowing by closing lips

Question 16

what are the 3 parts of the pharynx and where are they situated

Answer 16

nasopharynx - posterior to nasal cavity, superior to soft palate

oropharynx - posterior to oral cavity between soft palate and epiglottis

laryngopharynx - posterior to larynx, between epiglottis and oesophagus

Question 17

how do the oropharynx and part of the laryngopharynx aid in pulmonary aspiration

Answer 17

raising of the larynx towards the oesophagus reduces the chance of aspiration

epiglottis moves posteriorly aiding closure of laryngeal inlet

but if it does occur, cough reflex engages