Upper GIT Structure and Function

Question 1

What makes up the upper GIT?

Answer 1

Mouth
Oesophagus
Pharynx
Stomach

Question 2

Why do we chew?

Answer 2

-To make us happy :) it’s due to prolonging taste exposure and enjoying the taste more!
-Prevents against respiratory failure

Question 3

Is chewing voluntary or involuntary?

Answer 3

Voluntary

Question 4

How many salivary glands are in the mouth?

Answer 4

6- 3 pairs

Question 5

Name the three pairs of glands

Answer 5

Sublingual glands
Submandibular glands
Parotid glands

Question 6

Why does food need saliva before we swallow?

Answer 6

To moisten it and prevent it from causing irritation to the mouth and oesophagus

Question 7

What are the components of saliva?

Answer 7

Water
Mucins
Amylase
Electrolytes
Lysosomes

Question 8

If you have water and mucins, what does it produce?

Answer 8

Mucus

Question 9

What does amylase do?

Answer 9

Catalyses the breakdown of polysaccharides into disaccharide and glucose.

Question 10

Where is amylase secreted from?

Answer 10

Salivary glands and pancreas

Question 11

What is the pH of saliva?

Answer 11

Approx 7.4

Question 12

Why is i important to keep the mouth at a neutral, or nearly neutral, pH?

Answer 12

Because if it’s too acidic, it makes the teeth weaker and more easily damaged
If it’s too alkaline, it deposits a thing called matter on the teeth

Question 13

What are lysosomes?

Answer 13

Bacterial chemicals which can cause cleaving of polysaccharides and kill bacteria

Question 14

Is saliva controlled by parasympathetic or sympathetic NS?

Answer 14

Both

Question 15

Is the parasympathetic control inhibitory or stimulatory?

Answer 15

Stimulatory for all parts of the GIT

Question 16

Is the sympathetic control inhibitory or stimulatory?

Answer 16

Inhibitory for all but the saliva glands

Question 17

Which nerves provide the parasympathetic innervation to all the GIT?

Answer 17

Vagus nerves (nerve 10)

Question 18

Which nerves provide the parasympathetic innervation to salivary glands?

Answer 18

Facial nerves (nerve 7)
Glossopharyngeal (nerve 9)

Question 19

Describe the saliva produced by stimulation from the sympathetic NS.

Answer 19

Small volume, more viscous

Question 20

Describe the saliva produced by stimulation from the parasympathetic NS.

Answer 20

Larger volume, watery

Question 21

Why is saliva produced by stimulation from the sympathetic NS a lot thicker and less volume?

Answer 21

Due to the activation of Alpha 1 adrenoreceptors

Question 22

What happens if there is activation of the beta 2 adrenoreceptors?

Answer 22

Mainly amylase would be released

Question 23

So basically, what happens-
1. When the alpha 1 adrenoreceptor is activated
2. When the beta 2 adrenoreceptor is activated

Answer 23

1. More mucous produced
2. More amylase produced

Hmm check this. Doesn’t seem right.

Question 24

Where does the oesophagus go between?

Answer 24

Mouth and stomach

Question 25

How long is the oesophagus?

Answer 25

25cm

Question 26

What are the four layers of the oesophagus?

Answer 26

Mucosa Submucosa Muscularis externa Adventitia

Question 27

Which type of cells lines the oesophagus?

Answer 27

Stratified squamous epithelium

Question 28

Why is there keratin is the oesophagus?

Answer 28

It needs to be flexible and keratin provides strength

Question 29

What is the main function for the submucosal mucous glands?

Answer 29

Produce mucous for lubrication

Question 30

Describe the muscle in the muscularis exertna

Answer 30

Upper third is composed of skeletal muscle, lower two thirds are composed of smooth muscle

Question 31

What is the role of the upper and lower oesophageal sphincters?

Answer 31

Regulates movement of material in and out of the oesophagus

Question 32

Name the three phases of swallowing.

Answer 32

1. Oral phase 2. Pharyngeal phase 3. Oesophageal phase

Question 33

Which part of the brain controls swallowing?

Answer 33

Swalloqing centre in the medulla

Question 34

When the upper sphincter opens, when needs to happen at the same time?

Answer 34

The epiglottis needs to close over the trachea

Question 35

Describe the difference between vomiting and regurgitation.

Answer 35

Vomiting is a forceful expulsion of gastric content, regurgitation is non-forceful

Question 36

How long does it take the bolus (chewed food) to reach the stomach?

Answer 36

10 seconds

Question 37

How much volume does an empty stomach have?

Answer 37

50ml

Question 38

What volume can the stomach expand to fit?

Answer 38

1.5L

Question 39

Is there a change in pressure in the stomach depending on how full it is?

Answer 39

No

Question 40

What are the functions of the stomach?

Answer 40

-Temporarily stores ingested material -Dissolves food particles and initiates digestive process -Controls delivery of material to small intestine -Sterilises ingested material -Produces intrinsic factor (helps w Vitamin B12 absorbtion)

Question 41

Where will digestion start for foods like glucose and carbs?

Answer 41

Mouth

Question 42

Where will digestion start for proteins?

Answer 42

Stomach

Question 43

What type of acid is stomach acid?

Answer 43

Hydrochloric acid

Question 44

What are the two layers of the muscularis externa?

Answer 44

Circular muscle Longitudal muscle

Question 45

What does the circular muscle do to the lumen?

Answer 45

Narrows it

Question 46

What does the longitudal muscle do to the lumen?

Answer 46

Shortens it

Question 47

What is the function for the oblique muscle in the stomach?

Answer 47

It allows the stomach to twist and helps mix and break the food

Question 48

List the three layers of muscle of the stomach from outer to inner.

Answer 48

Longitudal, circular, oblqiue

Question 49

Which enzymes degrades protein?

Answer 49

Pepsin