Digestive System 1

Question 1

Describe enamel?

Answer 1

Crystalline rods or prisms of calcium phosphate and carbonate
No cells
Hardest tissue of the body
No sensation

Question 2

Describe dentin

Answer 2

Similar to bone but cells (odontoblasts) occur nearby in the pulp instead of scattered through the dentine

Question 3

Describe pulp?

Answer 3

Soft tissue

Blood vessels, nerves, lymphatics

Question 4

Describe cementum?

Answer 4

Calcified connective tissue covering the root of the tooth

Question 5

Describe the periodontal ligament?

Answer 5

The collagen fibres linking the bone of the socket (alveolar bone) to the cementum, and has a rapid turnover

Question 6

Three types of tastebuds?

Answer 6

Fungiform papillae
Filiform papillae
Circumvallate (8-12)

Question 7

What are the three major salivary glands?

Answer 7

Parotid (serous)
Sublingual (mucous)
Submandibular (mixed)

Question 8

When do salivary glands secrete?

Answer 8

After parasympathetic stimulation endured by seeing, smelling, tasting or thinking about food

Question 9

What is saliva made of?

Answer 9

Water, mucus and enzymes

Question 10

What enzymes are in the mouth?

Answer 10

Amylase (breaks down starchy debris around teeth) and lysozyme (antibacterial)

Question 11

Describe mucous and serous cells?

Answer 11

Mucous= viscous 
Serous= watery

Question 12

How does a tube gain surface area?

Answer 12

1. Plain tube
2. Circular folds
3. Finger-like projections
4. Simple tubular glands
5. Convolutions

Question 13

What are the four tunics that make up the gut wall?

Answer 13

Muscosa (mucous membrane)
Submucosa
Muscularis externa (external smooth muscle)
Serosa

Question 14

Parts of the mucosa?

Answer 14

Epithelium
Lamina propria
Muscularis mucosae

Question 15

Purpose of epithelium?

Answer 15

Protection, absorption or secretion (or all three)

Question 16

What is the lamina propria?

Answer 16

A soft fibrous bed of loose connective tissue on which the epithelium rests; carries nerves and blood capillaries, populated with defensive cells

Question 17

What is the muscularis mucosae and what does it do?

Answer 17

Two thin layers of smooth muscle; inner and longitudinal, and ur provides the mucosa with some movement independent of the external muscle coat (eg contractions squeeze secretions from gland or lymph along lacteals)

Question 18

What is the submucosa?

Answer 18

A thick bed of loose connective tissue carrying large blood vessels and nerves (submucosal plexus). It connects the mucosa to the external muscle coat, but allows some movement between the two

Question 19

What is the muscularis externa?

Answer 19

It’s into two layers to produce peristalsis- the inner layer is circular, the outer is longitudinal. The myenteric nerve plexus occurs between the two layers

Question 20

What is the serosa?

Answer 20

A slippery outer covering of the gut tube (except oesophagus); it is two layered with outer mesothelium sitting on a bed of connective tissue. Also known as the visceral peritoneum. Where structure is not in contact with the body cavity the outermost connective tissue layer is referred to as the adventitia

Question 21

What is digestion?

Answer 21

Chemical breakdown of ingested food into absorbable molecules

Question 22

What is absorption?

Answer 22

Movement of nutrients, water and electrolytes through epithelial lining of the gut into blood or lymph