4.Digestive system

Question 1

define digestion

Answer 1

the breakdown of large insoluble molecules into small soluble molecules by chemical and physical (mechanical) means

Question 2

Features of mechanical digestion

Answer 2

-breakdown of food by (chewing, swallowing and muscular movements) into smaller pieces, increasing their SA without changing their chemical composition

Question 3

Features of chemical digestion

Answer 3

-chemical decomposition of food via enzymes and acids (mouth, stomach and intestine)

Question 4

eg of mechanical digestion

Answer 4

-chewing food/mastication -teeth
-muscular bags (smooth muscle in stomach) churns food

Question 5

eg of chemical digestion

Answer 5

-HCL in stomach and salivary amylase in mouth (saliva)

Question 6

overview of digestion

Answer 6

1.ingestion via mouth
2.mechanical an chemical breakdown of food
3.nutrient absorption in small intestine
4.elimination of waste via anus

Question 7

identify pathway of food through gastrointestinal tract

Answer 7

mouth (teeth), pharynx, oesophagus, stomach, small intestine, large intestine, rectum, anus,

Question 8

3 parts of small intestine

Answer 8

duodenum
jejunum
ileum

Question 9

parts of large intestine

Answer 9

caecum
ascending colon
transverse colon
descending colon
sigmoid colon and rectum

Question 10

three salivary glands

Answer 10

sublingual gland (below tongue)
submandibular gland (below mandible)
Parotid gland (below ears)

Question 11

function of mouth

Answer 11

to mechanically (teeth) and chemically (saliva) breakdown food

Question 12

function of oesophagus

Answer 12

transport food bolus from mouth to stomach via peristalsis

Question 13

function of stomach

Answer 13

-to mechanically (churn food through muscle contractions) and chemically breakdown food (through HCl)
-create pepsin (break down protein)
-secrete mucus that lubricates the stomach walls

Question 14

small intestine function

Answer 14

absorb nutrients into bloodstream

Question 15

large intestine function

Answer 15

-absorb water and electrolytes converting liquid chyme into semi solid (stool)
-form and propel faeces
-chemically digest food molecules using gut microbes

Question 16

rectum function

Answer 16

store (temporarily) faeces

Question 17

anus function

Answer 17

transport / provide pathway for faeces out of body-defecate

Question 18

salivary glands function

Answer 18

lubricate food- making it easier to pass through digestive system
chemically digest food (salivary amylase)
destroy ingested pathogens (non specific)

Question 19

pancreas function

Answer 19

regulate BGL via hormones (use insulin via endocrine gland)
produced and release enzymes for digestion (in pancreatic juice)

Question 20

liver function

Answer 20

secrete bile
metabolise fats, carbs and proteins
removes toxins

Question 21

gall bladder function

Answer 21

store, concentrate and release bile

Question 22

sphincter function

Answer 22

smooth muscle (circular) that closes off the stomach after a meal

Question 23

Identify the processes of digestion

Answer 23

Ingestion, propulsion, digestion, absorption, assimilation and elimination

Question 24

Define ingestion

Answer 24

intake of substances, passing of food or liquid from mouth into alimentary tract

Question 25

Define propulsion

Answer 25

movement of foo/liquid along GI tract

Question 26

Structure of stomach

Answer 26

Muscular bag on the left side of the abdominal region and posterior to liver -C shaped (4 regions)

Question 27

Identify 4 regions of stomach

Answer 27

cardia Fundus Body pylorus

Question 28

Define absorption

Answer 28

move digested food molecules across intestine wall into blood or lymph

Question 29

Structure of small intestine

Answer 29

-25 cm wide and 5 m long -joins and becomes large intestine

Question 30

Features of the small intestine to aid function

Answer 30

-single wall of columnar epithelial cells, short diffusion pathway, increased rate of diffusion -finger like projections (villi and microvilli), increaseSA of small intestine for absorption, increase rate of diffusion -each villus has large capillary network and lacteal, increase SA, increase rate of diffusion -mucous membrane, moist, protect intestine and provide lubrication (dissolve in solution)

Question 31

Structure of duodenum

Answer 31

1st part of small intestine, 25 to 30 cm long

Question 32

Function of duodenum

Answer 32

-final stage of digestion occurs here -secretin produced here to respond top acidic chyme (maintains pH)

Question 33

Structure of jejunum

Answer 33

2 m long, lined by villi and microvilli, middle section of small intestine

Question 34

Function of jejunum

Answer 34

absorb nutrients (90% of absorption)

Question 35

Structure of ileum

Answer 35

end section, 3 m long

Question 36

Function of ileum

Answer 36

absorb nutrients into blood

Question 37

define assimilation

Answer 37

movement of digested food molecules from bloodstream into cells

Question 38

Structure of pancreas

Answer 38

located in abdominal region, posterior to stomach, connected to duodenum by pancreatic duct

Question 39

Pepsin

Answer 39

made in stomach and breaks down proteins

Question 40

Secretin

Answer 40

made in duodenum and responds to acidic chyme

Question 41

amylase

Answer 41

made in pancreas and salivary glands and breaks down fats/lipids

Question 42

lipase

Answer 42

made in pancreas and breaks down fats/lipids

Question 43

trypsin

Answer 43

made in pancreas and breaks down proteins

Question 44

What is bile

Answer 44

water, mucous, mineral salts, bile pigments, bilirubin, bile slats and cholesterol

Question 45

function of bile

Answer 45

digest insoluble fats metabolise and absorb vitamins (KDEA) excrete bilirubin

Question 46

Define excretion

Answer 46

excretion of undigested food substance through anus after processing in blood

Question 47

Structure of large intestine

Answer 47

1.5 cm long, in-between small intestine and anus

Question 48

How are faeces formed

Answer 48

1. Undigested food (chyme) enters colon from intestine 2. H2O, salts and vitamins are reabsorbed 3. Dehydration and compaction of undigested matter 4. Semi solid faeces forms / stool

Question 49

What is faeces made of

Answer 49

60-70% water, fibre, dead and alive microbes, epithelial cells, fatty acid, mucous

Question 50

Rectum structure

Answer 50

starts at sigmoid colon and ends at anal canal, 13 cm long

Question 51

Structure of anus

Answer 51

-At end of digestive system (external opening) -contains inner and external sphincter

Question 52

Inner sphincter

Answer 52

is smooth muscle and involuntary

Question 53

External sphincter

Answer 53

is skeletal muscle and voluntary