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Flashcards in Digestive Deck (82)
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1

Name the order of layers in a tooth from enamel to pulp:

Enamel, periodontal ligament, cementum, detin, pulp

2

Describe the pulp:

It is a soft tissue that contains blood vessels, nerves and lymphatics

3

Describe the dentin:

It is similar to bone but contains odotondoblasts. Occurs near by the pulp not throughout the dentin

4

Describe enamel:

Crystilline rods or prisms of calcium/phosphate and carbonate. It contains no cells, so no sensation

5

What is the hardest tissue of the body?

Enamel

6

Describe cementum:

Calcified connective tissue covering the root

7

Describe the peridontal ligament:

Collagen fibres linking the bone of the socket (alveolar bone) to the cementum. It has a rapid turnover so it is constantly broken down and remade. Embedded in the ligament are mechanoreceptors that sense stretch and act as a protector and force transmitter.

8

What types of muscle fibres are found in the tounge?

Verticle, longitunal and trabsverse

9

What are the 3 types of pipillae found on the tongue?

Filliform
Fungiform
Vallate

10

Describe filiform papillae:

No taste buds (pointy)

11

Describe fungiform papillae:

Some taste buds
(Rounded)

12

Describe vallate pipillae:

They have lots of taste buds and a moat

13

What do mucus cells secrete and why?

A viscous solution for lubrication

14

What do serous cells secrete and why?

A watery secretion that consists of amylase and lysozome

15

What are the 3 pairs of salivery glands and what do they secrete?

Parotid (serous)
Sublingual (mucus)
Submandibular (mixed)

16

What is saliva made up of?

Water, mucus and enzymes

17

When do salivery glands secrete their secretions?

After parasympathetic stimulation induced by seeing etc food

18

What is the omentum?

A large, apron like fold of visceral peritoneum that hangs down from the stomach

19

What are the 4 ways of increasing surface area?

1. Circular folds - plicae circulare
2. Upwards projections (into lumen) - evaginations e.g villi
3. Downwards projections - invaginations e.g glands
4. Gross convolutions

20

What are the 4 linings of the gut tube starting from the lumen?

Mucosa
Submucosa
Muscularis externa
Serosa

21

What makes up the mucosa?

1. Epithelium
2. Lamina propria - loose connective tissue that carries blood vessels, nerves and defence cells
3. Muscularis mucosae - 2 layers of smooth muscle - inner circular and outer longitudinal

22

What makes up the submucosa?

A thick bed of loose connective tissue carrying larger blood vessels, lymph and nerves (submucosal plexus)

23

What makes up the muscularis externa?

2 layers of smooth muscle inner circular and outer longitudinal. Contains the myenteric nerve plexus

24

What makes up the serosa?

A slippery outer covering for the gut tube (except oesophagus). It is 2 layered with outermost mesothelial cells sitting on a bed of connective tissue. It is also known as the visceral peritoneum and when it is not attached to a body cavity it is adventitia

25

What controls the submucosal plexus and the myenteric nerve plexus?

The enteric nerve system which is self governing and is influenced by the autonomic nervous system

26

When the oesophagus is empty, what shape is it?

Collapsed

27

What are the 3 functions of the oesophagus?

Transport
Protection
No absorption, little secretion and no digestion

28

What is special about the epithelium layer of the oesophagus?

It is stratified squamous with a sacrificial layer for protection against hard food. Cells are replaced by division in basal layers then slow migration outwards. Old cells are shed from the surface outwards

29

What is special about the external muscle of the oesophagus?

It has some skeletal muscle in the upper third of the oesophagus to allow for rapid contraction and voluntary swallowing

30

What is special about the serosa on the esophagus?

It is a fibrous adventitia, because it does not lie in a body cavity