Digestive System Flashcards

Components, Layers of the Gut & Worms

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1
Q

What is the role of the digestive system?

A

It’s responsible for chemically and physically digesting large insoluble molecules into smaller soluble molecules, which can be absorbed into the blood stream,

And used for bodily processes (e.g. respiration, protein synthesis).

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2
Q

Buccal Cavity-
Chemical Digestion

A

Amylase breaks down starch and glycogen into maltose

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3
Q

Buccal Cavity-
Saliva

A

Moistens food and maintains pH (for enzyme activity)

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4
Q

Buccal Cavity-
Mechanical Digestion

A

The tongue moves food to the cutting and grinding surfaces of the teeth

Tongue rolls food into a bolus which is swallowed

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5
Q

Bolus

A

a ball like mixture of food and saliva that forms during chewing (mechanical digestion) which is swallowed into the stomach
It’s the same colour as the food eaten, and saliva gives it an alkaline pH

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6
Q

Oesophagus

A

A long tube which extends from the buccal cavity to the stomach.
It’s responsible for pushing the bolus into the stomach using peristaltic waves of muscle contraction. It’s also lubricated with mucus.

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7
Q

Layers of the gut

A

Serosa (outermost)
Muscle Layers
Sub-mucosa
Mucosa
Lumen

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8
Q

Serosa

A

The outer most layer of the gut made of a thick tough connective tissue to provide protection.

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9
Q

Muscle Layers

A

The second outer most layer of the gut. Used to contract in waves and squeeze food down (peristalsis)

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10
Q

Sub mucosa

A

The second inner most layer of the gut. Contains connective tissue, nerves, blood & lymph capillaries

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11
Q

Mucosa

A

Inner most layer of the gut. This area secretes mucus and can secrete digestive juices.

In the ileum it’s covered with microvilli to increase SA

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12
Q

Stomach

A

A J shaped organ found at the end of the oesophagus which physically churns up food using muscles from the stomach wall
It also chemically breaks down food by releasing gastric juices

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13
Q

Mucus

A

Produced by goblet cells throughout the digestive system (e.g. stomach) to lubricate food and protect organ walls from self digestion via enzymes

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14
Q

Gastric Juice

A

A digestive fluid produced within the stomach lining with an acidic pH made up of mainly HCl, mucus, endopeptidase (pepsin), lipase

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15
Q

What produces gastric juice?

A

Gastric glands in the mucosa

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16
Q

Oxyntic Cells

A

Produce hydrochloric acid (HCl) in the stomach which kills bacteria and lowers pH down to 2 (for optimum pepsin enzyme activity)

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17
Q

Pepsinogen

A

The inactive form of endopeptidase (pepsin) which is activated by HCl to break down polypeptides into peptides

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18
Q

Liver

A

Produces Bile

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19
Q

Gall Bladder

A

Stores Bile and releases it to the duodenum from the bile duct

20
Q

Bile

A

Emulsifies lipids to maximise the SA for lipase enzyme action & digestion/absorption

Alkaline in pH to neutralise stomach acid and form slightly alkaline (food)

21
Q

Pancreas

A

Produces enzymes that are released into the duodenum via the pancreatic duct

22
Q

Pancreatic Juice

A

The pancreatic enzymes produced by the pancreas and released into the duodenum by the pancreatic duct (slightly alkaline in pH)

23
Q

What (pancreatic) enzymes does the pancreas produce?

A

Carbohydrase (pancreatic amylase)
Lipase
endo & exopeptidase

24
Q

Duodenum

A

The start of the small intestine (connected to the stomach) where food is further digested on the epithelial cells of the villi

25
Q

What enzymes are in the duodenum?

A

amylase
maltase
lactase
sucrase
endopeptidase
exopeptidase
dipeptidase

26
Q

Amylase

A

A type of carbohydrase which hydrolyses starch into maltose

It is found in the mouth (from salivary glands) and duodenum (from pancreas)

27
Q

Maltase

A

A type of disaccharidase which hydrolyses maltose into alpha glucose

Found membrane bound in the duodenum

28
Q

Sucrase

A

A type of disaccharidase which hydrolyses sucrose into glucose and fructose

Found membrane bound in the duodenum

29
Q

Lactase

A

A type of disaccharidase which hydrolyses lactose into glucose and galactose

Found membrane bound in the duodenum

30
Q

(pancreatic) Lipase

A

Hydrolyses triglycerides into monoglycerides (and then eventually into fatty acid and glycerol)

31
Q

Endopeptidase

A

A type of protease which hydrolyses non-terminal (central) peptide bonds to form smaller poly peptides

Found in the stomach and duodenum

32
Q

Trypsinogen

A

The inactive form of Trypsin (a type of endopeptidase) which becomes activated by enterokinase

33
Q

Exopeptidase

A

Type of protease which hydrolysis terminal (end) Peptide bonds to form dipeptides and amino acids

Found in the stomach and ileum

34
Q

Dipeptidases

A

Type of protease which hydrolyses specifically peptide bonds on dipeptides to form amino acids

Found membrane bound in the duodenum

35
Q

Absorbing Glucose

A

Na+ actively transported out of the ileum into the blood using sodium potassium pump. (Low concentration in ileum cells).

Na+ diffuses from lumen to epithelium by sodium glucose co transporter.

Glucose then diffuses out of the cell into the bloodstream through facilitated diffusion

36
Q

Absorbing Amino Acids

A

Active transport using carrier proteins into villi cells and then facilitated diffusion into capillaries

37
Q

Absorbing minerals

A

facilitated diffusion and active transport

38
Q

Absorbing fats

A

Lipase breaks down lipids into monoglycerides & fatty acids

Bile & lipase act on the triglycerides to form a micelle made up of monoglycerides, fatty acids and bile salts

Break and move into the cell membrane, reform before moving to the ER or Golgi

Modified into chylomicrons, which allow them to move into the lacteal by exocytosis and then be drained into the blood

39
Q

Ileum

A

The final part of the small intestine (connected to the duodenum) which mainly absorbs any left over nutrients/substances

40
Q

Colon

A

The longest section of the large intestine, which is responsible for absorbing any excess water and some nutrients

41
Q

Rectum and Anus

A

Rectum- lower part of the large intestine where faeces (waste products of digestion) are stored

Anus- the opening at the end of the rectum where faeces are released from

42
Q

Tapeworm

A

A (parasite) disease caused by eating uncooked/ raw meat or by not washing hands

The heads attach to the inner walls of the small intestine and feed off food being digested

43
Q

Identifying Tapeworms

A

Pieces of white, flat, rectangular worms in the faeces about the size of a grain of rice

44
Q

Symptoms of Tapeworm

A

tummy pain
diarrhoea
nausea
vomiting
weight loss
change in appetite

45
Q

Transmission of Tapeworm

A

raw/undercooked meat
faecel contaminated water
very close contact to those infected

46
Q

Treating Tapeworm

A

Anti Worm medication

47
Q

Reducing spread of Tapeworm

A

food well cooked
fruit & veg throughly washed
only drink clean water

Hands thoroughly washed before food, after toilet or after touching animals