Drive - swallowing and salivary glands

Question 1

What initiates swallowing?

Answer 1

When pressure receptors in the walls of the pharynx are stimulated by food and drink (forced into the rear of the mouth by the tongue)

Question 2

Explain the process that occurs during the voluntary stage of swallowing:

Answer 2

Food is compressed against the roof of the mouth. then is pushed towards the oropharynx by the action of the tongue.
Buccinator and suprahyoid muscles manipulate the food

Question 3

What is the role of the buccinator and supra hyoid muscles? (3)

Answer 3

Manipulate food during chewing.

Elevate the hyoid bone

Flatten the floor of the mouth

Question 4

What causes the nasopharynx to be closed off?

Answer 4

The soft palate (via the action of the muscles of the palate) and the pharynx is shortened and widened by elevation of the hyoid bone

Question 5

What causes the food to pass down to the stomach?

Answer 5

Sequential contraction of the constrictor muscles followed by the return of the hyoid bone and pharynx (to normal). Upper Oesophageal sphincter relaxes, Peristatic waves move the food towards the relaxed lower oesophageal sphincter into the stomach.

Question 6

What is the gag reflex?

Answer 6

The reflex elevation of the pharynx (often followed by vomiting) due to irritation of the oropharynx

Question 7

Which nerve(s) cause/allow the gag reflex?

Answer 7

sensory = glossopharyngeal
effector = vagus nerve (causes the constriction of the muscles)

Question 8

What are the main functions of saliva (3)?

Answer 8

Lubrication for mastication

Maintaining oral pH

Digestion via salivary amylase

Question 9

What is oral pH maintained between?

Answer 9

pH = 6.2 - 7.4

Question 10

What is the daily secretion of saliva?

Answer 10

800 - 1500 ml in adults

Question 11

What do serous secretions contain?

Answer 11

alpha amylase for starch digestion

Question 12

What do mucous secretion contain?

Answer 12

mucins for lubrication of mucosal surfaces

Question 13

What type of secretion does the parotid gland produce?

Answer 13

serous

Question 14

What is the parotid gland innervated by?

Answer 14

Sympathetic = mandibular branch of the trigeminal nerve
Parasympathetic = glossopharyngeal nerve

Question 15

What is the submandibular gland supplied by?

Answer 15

Sympathetic = Lingual nerve (branched from the facial nerve)
Parasympathetic = chorda tympani branch of the facial nerve.

Question 16

What type of secretion does the submandibular branch produce?

Answer 16

Both mucous and serous

Question 17

What type of secretion does the sublingual gland produce?

Answer 17

Mainly mucous but some serous

Question 18

What factor affect the composition and amount of saliva produced? (9)

Answer 18

Flow rate

Circadian rhythm

Type and size of gland

Duration and type of stimulus

Diet

Drugs

Age

Gender

Time of day

Question 19

How does mucosa aid in the defence of the oral cavity?

Answer 19

Forms a physical barrier

Question 20

How do the salivary glands aid in the defence of the oral cavity?

Answer 20

Washes away food particles which bacteria or viruses could use as metabolic support

Question 21

How do the palatine tonsils aid in the defence of the oral cavity?

Answer 21

Immune surveillance system

Question 22

How do the surrounding lymphatic system aid in the defence of the oral cavity?

Answer 22

Contain a broad range of functional immune cells

Question 23

When unstimulated (e.g. no food) what is the main source of saliva?

Answer 23

Submandibular gland

Question 24

When stimulated what is the main source of saliva?

Answer 24

Parotid gland

Question 25

What are the two different types of epithelial cells form which salivary glands are composed?

Answer 25

Serous acini and mucous acini

Question 26

Give 5 key facts about serous acini:

Answer 26

Dark staining nuclei Nucleus in basal third Small central ducts Mainly found in the parotid gland Secrete: water and alpha amylase

Question 27

Give 5 key facts about mucous acini:

Answer 27

pale staining "foamy" appearance Nucleus at base Large central duct Found in the submandibular and sublingual glands Secrete: mucous

Question 28

What is mucous comprised of?

Answer 28

water and glycoproteins

Question 29

What are the 2 types of intralobular ducts ?

Answer 29

intercalated and striated

Question 30

What is the function of the intercalated ducts?

Answer 30

Connect the acini with the striated ducts

Question 31

What is the (histological) appearance of intercalated ducts?

Answer 31

Short narrow duct segments lined with cuboidal cells

Question 32

What is the function of the striated ducts?

Answer 32

Main site for reabsorption of NaCl

Question 33

What is the histological appearance of striated ducts?

Answer 33

Highly folded basal membrane into microvilli with lots of mitochondria to provide energy for the active transport of HCO3.

Question 34

What is the function of the intralobular ducts?

Answer 34

To modify the electrolyte composition of saliva.

Question 35

Combined what % of the salivary flow is contributed to by the parotid, submandibular and sublingual glands?

Answer 35

80%

Question 36

Where are the minor salivary glands found?

Answer 36

In the submucosa, lips, cheeks, hard palate, soft palate and the tongue.

Question 37

What is the sublingual gland supplied by?

Answer 37

``` Sympathetic = Lingual nerve (branched from the facial nerve) Parasympathetic = chorda tympani branch of the facial nerve. ```

Question 38

What does sympathetic innervation of the salivary glands cause?

Answer 38

Stimulation of salivary secretion

Question 39

What does parasympathetic innervation of the salivary glands cause?

Answer 39

Inhibition of salivary secretion