Mouth and Oesophagus

Question 1

What type of muscle and fibre are Lips and cheeks made up of?

Answer 1

Skeletal muscle in elasto-fibro CT

Question 2

What is the oral cavity lined by?

Answer 2

stratified squamous epithelium, slightly keritanised on gums tongue hard palate for protection

Question 3

What is the tongue composed of?

Answer 3

Skeletal muscle, interspersed with glands and covered with mucous membranes

Question 4

How is the tongue intrinsic and extrinsic?

Answer 4

Intrinsic - to change shape

Extrinsic - allow movement

Question 5

What is the position of the oesophagus?

Answer 5

Posterior, passes down midline of thorax through diaphargm at oesophageal hiatus ‘gap’ to enter abdomnen.

Question 6

Where does the oesophagus recieve innervation from?

Answer 6

vagus nerve , 10th cranial

Question 7

Describe layers of the oesophagus?

Answer 7

Mucosa - nonkeritanised stratified squamous as transit passage
Submucos - mucous secreting glands
Muscularis - skeletal, transitional, smooth
Serosa - is fibrous CT instead

Question 8

What happens to the mucosa of oesophagus longitudinal folds?

Answer 8

Flatten out when filled

Question 9

What are the 2 oesophageal sphincters?

Answer 9

Hypopharyngeal sphincter of skeletal muscle (upper)

Lower gastro-oesophageal or cardiac sphincter - has high pressure

Question 10

What is gustation?

Answer 10

Taste

Question 11

How is taste detected?

Answer 11

detects chemicals in saliva solution by use of chemoreceptors - taste buds

Question 12

What does taste have a strong relationship with?

Answer 12

Olfaction - smell

Question 13

What are the 5 primary tastes?

Answer 13

Sour - acid h+ content
Salt - metal ions, Na modifies saltiness
Bitter - plant alkaloids such as caffeine
Sweet - mono-di saccharides, sugars
Umami - glutamate content meatiness

Question 14

Can all taste buds detect all taste?

Answer 14

Yes, but sensitive to 1

Question 15

What is the position of 5 tastes on the tongue?

Answer 15

Tip - sweet
Sides of tip - salty
Back - bitter
Sides - sour

Question 16

How many taste buds on tongue and where?

Answer 16

10,000 taste buds on epithelium on papillae

Question 17

What are the 4 papillae and where are they based?

Answer 17

Filiform - not involved
Fungiform - mushroom on dorsal surface
Foliate - leaf on tip and sides
Circumvallate - grooved anterior/posterior

Question 18

What do taste buds contain?

Answer 18

40-100 basal stems cells and gustatory

Question 19

How often are taste buds replaced?

Answer 19

7-10 days by division of basal stem cells

Question 20

Where are microvilli?

Answer 20

are the receptor membrane, project through taste pore to surface in saliva

Question 21

What neurones are around gustatory cells?

Answer 21

Dendrites of sensory nerves - for brain perception of taste

Question 22

What happens to taste?

Answer 22

Substance in saliva
enters taste pore attached to membrane
depolarisation of taste cell
neurotransmitter release to stimulate sensory neurone
neural path to brain 7 9 10 cranial
Impulses to tractus soliatarius of medulla to thalamus to parietal cortex

Question 23

What disorders of the taste are there?

Answer 23

Aguestia - loss of taste could be from medication causing neuronal damage
Alterations in taste perception drug induced
Genetic deficiences - phenlythiourea cant taste bitter

Question 24

What are 3 major pairs of salivary glands?

Answer 24

Parotid, submandibular, sublingual and numerous glands through mucosa

Question 25

What type of secretions do each gland do?

Answer 25

Parotid - serous, water, a-amylase Submandibular - seriousm mucous, weak a-amylase and lysozyme Sublingual - mucous, thick viscous

Question 26

What is saliva composed of?

Answer 26

>99% water <1% solids, ions 50+ proteins such as a-amylase, mucins, lysosome, immunoglobulins

Question 27

What is PH of saliva?

Answer 27

6.2-8

Question 28

What are flow rates of saliva and how much produced daily?

Answer 28

0.05 sleep 0.5 - 7ml at rest 1/2 L daily

Question 29

Why is saliva needed?

Answer 29

For lubrication, movement, chewing, swallowing, taste sensation Thirst, speech, chemical balance for tooth enamel

Question 30

What does saliva digest?

Answer 30

A-amylase hydrolyses a-14 glyogosidic link of starch

Question 31

What does saliva protect from?

Answer 31

Bacteriostatic , mucins, iga

Question 32

How does saliva help dissolve absorbale drug?

Answer 32

glyceryl trinitrate - escapes first pass metabolism

Question 33

What are disorders of salivary glands?

Answer 33

Mumps = infection of parotid by myxovirus | Xerostomia - dry mouth, people on medication, autoimmune, diabetes, age atrophy

Question 34

What can lack of saliva do?

Answer 34

Make swallowing difficult lead to problems with halitosis, gum disease, mouth infections, digestion not impaired if sufficient a-amylase from pancreas

Question 35

What is mastication?

Answer 35

Chewing

Question 36

How are teeth adapted to function?

Answer 36

Incisors - chisel for cutting, nipping Canines - tearing, piercing Molars for grinding crushing

Question 37

When chewing how is jaw and tongue controlled?

Answer 37

Touch and pressure receptors in oral cavity and stretch receptors in muscles

Question 38

What is the process of chewing?

Answer 38

up and down - biting of incisors Side to side - crushing by molars = mixing food with saliva to lubricate to allow taste

Question 39

What is the max force generated by muscles for chewing?

Answer 39

250N to 900 N

Question 40

Why is occulusal contact of molars important?

Answer 40

Determining efficiency of chewing

Question 41

What are jaw movements involved with?

Answer 41

voluntary, involve cerebral cortex and skeletal muscle

Question 42

What is bite strength controlled by?

Answer 42

sensory receptors in teeth signals to brain stem to stop/reduce

Question 43

What does the tongue move with?

Answer 43

Lower jaw, shape alters to collect food in tongue until food ground, tongue moves bolus to swallowing

Question 44

What is deglutition?

Answer 44

Swallowing

Question 45

What kind of movement occurs with food processed?

Answer 45

voluntary to involuntary

Question 46

What are 3 phases of swallwing?

Answer 46

Voluntary, pharyngeal, oesophageal

Question 47

What happens in voluntary phase?

Answer 47

tongue seperates food into bolus and moves back and up to back of mouth

Question 48

What happens in pharyngeal phase?

Answer 48

food into pharynx activate pressure receptor in palate and impulses in trigem and glossophar nerve to medulla cause elevation of soft palate, impulses from swallow centre inhibit respiration closes glottis, bolus tilts epiglottis back, sphincter opens by contraction, bolus passes and closes, glottis open breathing resumes

Question 49

What happens in the oesophageal phase?

Answer 49

food moves down by peristalsis of circ SM by relaxationm progress by autonomic vagus nerve by swallow centre, as wave moves down, lower sphincter relaxes allow food to enter and close to prevent reflux

Question 50

What increase the tone of sphincter and when?

Answer 50

Increased gastrin when stomach is filled

Question 51

What is dysphagia?

Answer 51

Difficulty of swallowing

Question 52

What are disroderds of deglutition?

Answer 52

Damage to cranial nerve or medulla swallow centre degenerative disease of skeletal muscle -myasthenia gravis, polio dystrophy, defects in autonomic nerves e.g chagas diseases by trypan infection, achalsasia Swallow reflex inactive, hiatus hernia, diffuse oesopha spasm, thick sm, GORD - reflux disease heartburn