Digestive system overview: intro to internal organs

Question 1

What does the digestive system consist of

Answer 1

digestive tract- oral cavity, oesophagus, stomach, small/large intestine, anus, salivary glands, liver pancreas

Also called GASTOINTESTINAL TRACT

Helps to obtain molecules from ingested food

Question 2

What do the structures of digestive tract allow us to do

Answer 2

ingestion- food can enter oral cavity

Mastication- chewing to make pieces smaller

Motility- muscular movement of material down tract eg peristalsis

Secretion- digestive enzymes, acid/alkaline fluids, bile

Hormone release- to control motilty and secretion

Chemical digestion- using enzymes to make large molecules into smaller soluble molecules

Absorption- small molecules absorbed into blood and lymph

Elimination- indigestible, unabsorbed molecules

Question 3

What are internal organs divided into

Answer 3

Hollow- tube/pouch shape. Consist of cavity and wall
GI, respiratory, urogenital tract, gallbladder, urinary
bladder

Solid (parenchymal)- liver, pancreas, kidney, spleen, ovary, most glands

Question 4

parenchymal organs structure

Answer 4

parenchyma- part of organ that performs specific function.
Epithelial origin
Eg hepatocytes in liver

Stroma- skeleton of the organ: support, nourish, regulate
Dense connective tissue
Investing capsule- lobes, lobules, segments
interstitial fluid
Blood, lymphatic vessels, nerves
External surface covered by serosa

Question 5

hollow organs structure

Answer 5

Mucosa- epithelium, lamina propria, muscularis mucosae

Submucosa- blood/lymph vessels, submucosal nerve plexus

Muscularis- smooth muscle -stratum circulare + longitudinale
Myenteric nerve plexus

Serosa- LOOSE connective tissue with blood/lymph vessels
White adipose tissue, mesothelium lining

Question 6

If epithelium is the bodys first line of defence, what does the mucosal immune system do?

Answer 6

lamina propria is rich in macrophages and lymphocytes=IgA antibodies

lymph tissue in submucosal layer- MALT

Question 7

difference between tunica serosa and tunica adventitia

Answer 7

If theres no connection with the serous layer (mesothelium) then its adventitia eg oesophagus

secures organ to surrounding tissues

Question 8

what does duodenum have that produces mucous for protection

Answer 8

Brunner glands