Digestive system

Question 1

main functions of digestive system:

Answer 1

• ingestion
• secretion
• mixing and propulsion
• digestion (mechanical, chemical)
• absorption
• defecation

Question 2

define bolus:

Answer 2

soft rounded mass of food that is swallowed

Question 3

define chyme:

Answer 3

semifluid mixture of partly digested food, and digestive secretions
- in stomach and small intestine

Question 4

define feces:

Answer 4

discharged from rectum, from large intestines

- made up of bacteria, excretions and food residue```

Question 5

list parts of alimentary canal:

Answer 5

aka gastrointestinal tract

• oral cavity
• pharynx
• oesophagus
• stomach
• small intestine
• large intestine

Question 6

list accessory digestive organs:

Answer 6

• teeth
• tongue
• salivary glands
• liver
• gallbladder
• pancreas

Question 7

what is the alimentary canal: general

Answer 7

hollow tube with lumen, layers:

• mucosa
• submucosa
• muscularis
• serosa/ adventitia

Question 8

features: mucosa

Answer 8

mucous membrane

• epithelial lining: enteroendocrine cells
• lamina propria (areolar ct) MALT
• muscularis mucosae (inner circular/ outer longitudinal layer) - smooth muscle

Question 9

features: submucosa

Answer 9

areolar ct.

• blood,
• lymph vessels
• submucosal (Meisnner’s) nerve plexus (ENS)`

Question 10

GENERAL features: muscularis

Answer 10

• internal (circular) and external (longitudinal) muscle layer
• myenteric (Auerbach’s) nerve plexus (ENS)

Question 11

type of muscle in muscularis layer and eg: skeletal and smooth muscle

Answer 11

skeletal:
- mouth
- pharynx
- superior/ middle part of - - oesophagus
- external anal sphincter

smooth muscle: others

Question 12

features: serosa/ adventitia

Answer 12

• serous membrane (covered by serous fluid)
• areolar ct.
• blood vessels, lymph vessels, simple squamous epithelium (mesothelium)

adventitia: in oesophagus (single layer of ct.)

Question 13

features: peritoneum

Answer 13

largest serous membrane: abdominopelvic cavity

• parietal, visceral layers
• peritoneal cavity (serous fluid)

Question 14

list retroperitoneal organs:

Answer 14

duodenum, pancreas, ascending, descending colon, kidneys, adrenal glands

Question 15

features: oral cavity

Answer 15

buccal cavity

• cheeks
• tongue
• hard, soft palate
• uvula
• lips, teeth
• oral vestibule
• covered by mucous membrane: stratified squamous epithelium (keratinised in high impact areas)

Question 16

features: tongue

Answer 16

• 2 halves separated by median septum
• mucous membrane: lingual frenulum

skeletal muscle:

• extrinsic- og outside of tongue, floor of oral cavity moves tongue side to side/ in and out
• intrinsic: og and insert into ct. of tongue, changes size and shape

Question 17

tongue: papillae

Answer 17

• fungiform: taste buds on tip of tongue and margins
• vallate: V shaped, post taste buds
• foliate: lateral taste buds. degenerate in childhood, scarce
• filliform: anterior 2/3, no taste buds, touch receptors

Question 18

teeth: general features

Answer 18

alveolar processes covered by gingiva (gum), periodontal ligament attachment

• crown (above gingiva)
• neck
• root (within socket)

tissues: high Ca salts
- dentin
- enamel
- cementum

• pulp cavity: ct, nerves, blood vessels, lymph
• root canals
• apical foramen

Question 19

how many dentitions:

Answer 19

deciduous (milk): 20

permanent: 32

Question 20

types of teeth

Answer 20

• incisors
• canines
• premolars
• molars

Question 21

dental caries:

Answer 21

decay of enamel, dentin into pulp

Question 22

features: salivary major and minor glands

Answer 22

exocrine glands:
major paired: (90% of saliva)
- parotid
- submandibular
- sublingual

minor: (70% of mucus)
- lingual
- labial
- buccal
- molar
- palatine

Question 23

salivary glands: secretory portion and ducts

Answer 23

secretory: acini
- blind sacs (secretory cells)
produces secretions which drains to intercalated ducts -> striated ducts -> excretory ducts
- mucous, serous, mixed ducts

Question 24

parotid, submandibular and sublingual salivary gland secretions:

Answer 24

parotid: serious only
submandibular: mixed
sublingual: mostly mucous

Question 25

features: saliva

Answer 25

99. 5% water - keeps mucous membrane moist - cleans teeth and mouth - lubricates, dissolves and starts chemical breakdown of food (amilase, lipase) - parasympathetic and sympathetic control

Question 26

features: pharynx

Answer 26

- connects nasal cavity and oesophagus - wall: skeletal muscle, lined with mucous membrane - passageway for food and air - nasopharynx - oropharynx: stratified squamous epithelium - laryngopharynx: sse, begins at hyoid bone

Question 27

features: oesophagus

Answer 27

- muscular tube - through mediastinum, through oesophageal hiatus -> ends at stomach - upper, lower sphincters 4 layers: - mucosa (sse non-k), muscularis, adventitia, submucosa

Question 28

deglutition: list stages

Answer 28

voluntary, pharyngeal, oesophageal

Question 29

deglutition: features

Answer 29

v: bolus passed into oropharynx p: involuntary passage of bolus- through pharynx to oesophagus o: involuntary passage of bolus- from oesophagus to stomach