Upper GI structure

Question 1

What is the purpose of chewing

Answer 1

Prolong taste experience

Defence against respiratory failure - prevent blockage of airways

Question 2

How is chewing voluntarily controlled

Answer 2

Somatic nerves innervating the skeletal muscle of jaw/mouth

Question 3

What is pathway of the reflex control of chewing

Answer 3

Contraction of jaw muscle, which creates a pressure of food against the gums/hard palate and tongue

This pressure stimulates mechanoreceptor, that inhibit jaw muscles,

This then reduce pressure causing jaw to contract again

Question 4

What is the three salivary glands and where do they sit in reference to the oral cavity

Answer 4

Sublingual - Underneath the tongue

Submandibular - underneath the jaw

Partoid - Largest and sits above

Question 5

What is the 5 components found in salvia

Answer 5

Water 
Muccins 
Alpha amylase 
Electrolytes 
Lysozyme

Question 6

What is the purpose of water in saliva

Answer 6

Softens, moistens and dilute particles creating a solvent to ease digestion

Question 7

What does Muccins combins with to form Mucus

What is the Purpose of Mucus

Answer 7

Water and Muccins creates Mucus

Mucus is a viscous solution with a lubricant function

Question 8

What is the function of alpha amylase

Answer 8

Catalyses the brakdown of polysaccaharides / complex carbohydrates into glucose

Question 9

What is the purpose of the electrolytes in the saliva

Answer 9

Control the tonicity and ph

Question 10

What is the purpose of lysozyme in salvia

Answer 10

Baceriocidal, kills of unwanted components at first entry part of the body

(by breaking down polysaccharide component of bacterial cell wall)

Question 11

What kind of gland is a salvia gland

Answer 11

Exocrine gland -releases its secretions external to the body

Question 12

What stimulates watery salivary secretion

Answer 12

parasympathetic intervention via the cranial nerves facial + glossopharnygeal

Question 13

What stimulates viscous salvia with high mucus content

Answer 13

Sympathetic intervention through alpha 1 adrenoreceptros

Question 14

What stimulates viscous salvia with a high amylase content

Answer 14

Sympathetic intervention of beta 2 adrenoceptors

Question 15

How does reflex control work in the secret of saliva

Answer 15

The presence of food in the mouth stimulates the chemceptors due to the pressure in the mouth, triggering the secretion of saliva

Question 16

What is the cell arrangement of the mucosa layer in the oesophagus

Answer 16

Mucosa is a Non keratinised stratified squamous epithelium

Question 17

Why isn’t keratin present in the oesophagus

Answer 17

Needs to remain flexible

Question 18

What Layer of the oesophagus is is mucous glands and serous glands present and what is their function

Answer 18

Found in submucosa layer

Mucus glands produce mucus for lubrication

serous glands produces amylase

Question 19

Why is the superior part of the oesophageal muscular extern layer skeletal and the inferior part is smooth muscle

Answer 19

Skeletal muscle present in the upper third for the swallowing reflex

Question 20

What helps regulate material in and out of oesophagus

Answer 20

Upper and lower spinchters

Question 21

What happens in oral phase of swallowing

Answer 21

You voluntarily chose to swallow and bolus is pushed back to the mouth by the tongue

Question 22

What starts of the sequence of the pharyngel phase

Answer 22

The presence of the bolus (chewed food)

Question 23

What co-ordiantes the relflex contractions of the pharyngeal muscles

Answer 23

The swallowing centre in the medulla

Question 24

What is the first reflex of the pharyngeal phase

Answer 24

Soft palate reflected backward and upward (closes off nasopharynx)

Question 25

What happens as the bolus approaches the oesophagus in the pharyngeal phase of swallowing

Answer 25

Upper oseophageal sphincter relaxes and epiglottis covers opening to larynx (prevents food entering trachea)

Question 26

What is the affect of the epiglottis covering the opening of the larynx when you swallow

Answer 26

Breathing is inhibited

Question 27

What happens once food has entered the oesophagus in the pharyngeal phase

Answer 27

Upper Oesophageal spinchter contracts Epiglottis opens again Prevents reflux of food

Question 28

In the oesophageal phase how is the bolus propelled to the stomach and how long does this take

Answer 28

Through a peristaltic wave Propelled in 10 seconds

Question 29

What happens to the lower oesophageal spinchter as the bolus enters the stomach

Answer 29

Lower oesophageal spinchter relaxes

Question 30

What is initiated following the relaxation of the lower oesophageal sphincter and the bolus entering the stomach

Answer 30

Receptive relaxation of the stomach

Question 31

What occurs in receptive relaxation of the stomach

Answer 31

Relaxation of thin, elastic smooth muscles of the fundus and the body of the stomach which therefore increases the volume of the stomach

Question 32

What coordinated the receptive relaxation of the stomach

Answer 32

Vagal reflexes

Question 33

What is the overall functions of the stomach

Answer 33

Temporary store of ingested material Dissolve food particles and initiate digestive process Control delivery of contents to small intestine Sterilise ingested material Produce intrinsic factor (Vitamin B12 absorption)

Question 34

What does the stomach overall control the rate of

Answer 34

Digestion

Question 35

hat is the three different parts of the stomach

Answer 35

``` Top = Fundus Middle = Body Bottom = Antrum ```

Question 36

What is the muscular changes in the stomach from top to bottom and why

Answer 36

Muscle at the Top/Fundus is thinner Muscle moving down the stomach becomes thicker to help in the contractions of digestion and to squeeze products of digestion out into the duodenum

Question 37

What is the two normal muscle layers of the stomach and the third additional muscle layer found at the bottom of the stomach

Answer 37

Longitudinal - outer Circular - middle Additional: Oblique muscle layer - inner

Question 38

Where is the cardiac region located on the stomach

Answer 38

In-between the lower oesophageal spinchter and the funds

Question 39

Where is the pyloric spinchter located

Answer 39

In the pyloric region that sits above the duodenum

Question 40

Why doesn't stomach stretch when increasing in volume

Answer 40

As submucosa and mucosaa are arranged as folded (Rugae) when the stomach is empty

Question 41

What is present on the lumenal surface of the stomach (in the mucosa)

Answer 41

``` Gastric pits (Surface mucus cells) Gastric glands (Mucus neck cells +parietal cells + chief cells + G cells + D cells ) ```