Digestive

Question 1

What is the overall purpose of the digestive system?

Answer 1

Extract nutrition
Remove waste

Question 2

What does the mouth do?

Answer 2

Teeth mechanically break down food
Tongue mixes food + saliva into a bolus
Saliva contains amylase to begin chemical digestion

Question 3

What does the pharynx do (digestive)?

Answer 3

Muscular tube from mouth to oesophagus
Rhythmic contractions = peristalsis to move food bolus

Question 4

What does the oesophagus do?

Answer 4

Muscular tube to stomach
Moves bolus via peristalsis
Lower oesophageal sphincter prevents stomach content back flow

Question 5

What does the stomach do?

Answer 5

Secretes gastric juices containing hydrochloride acid and pepsin to chemically digest
Muscular wall mixes juices with food = chyme

Question 6

What is reflux?

Answer 6

When the lower oesophageal sphincter is weak or too relaxed stomach contents can back flow into the oesophagus
SX: heartburn, regurgitation, hoarse, cough

Question 7

What is a peptic ulcer?

Answer 7

Sores on the stomach lining
Usually caused by H. Pylori infection or NSAID use
SX: heartburn, indigestion, nausea, GI bleed

Question 8

What does the small intestine do?

Answer 8

Duodenum: receives digestive enzymes from the pancreas and bile from the liver/gall bladder and mixes with chyme
Jejenum: absorbs nutrients
Ileum: further absorption including B12, bile salt, water and electrolytes

Contains villi to increase surface area for absorption

Question 9

What is gastroenteritis?

Answer 9

Inflammation of stomach or intestines caused by an infection
SX: D+V, nausea, pain, fever

Question 10

What is a hernia?

Answer 10

A bulge where an organ or tissue protrudes through a weakened area.
Commonly inguinal (groin/scrotum) and hiatal (stomach through diaphragm)
May become strangulated causing ischemia, necrosis or obstruction

Question 11

What does the liver do (digestive)?

Answer 11

Produced bile to digest fat
Metabolises nutrients from small intestines
Detoxification
Stores vitamins and minerals
Produces clotting proteins

Question 12

What is cirrhosis?

Answer 12

Chronic condition of scarring on the liver causing impaired function
Caused by hepatitis, alcohol, fatty liver disease
Liver gets repeatedly injured —> tries to repair resulting in inflammation and scarring —> lots of scarring forms nodules

Question 13

What is hepatitis?

Answer 13

Inflamed liver
Caused by virus, medication, alcohol or autoimmune disease
SX: jaundice, pain, n+v, dark urine

Question 14

What does the gall bladder do?

Answer 14

Stores and concentrates bile from the liver
Ejects it into the small intestine via the common bile duct

Question 15

What are gallstones?

Answer 15

Hard collections of bilirubin or fat in the gallbladder or bile duct
SX: right upper quadrant pain, usually after a meal/at night, n+v

Question 16

What does the pancreas do (digestive)?

Answer 16

Release digestive enzymes into the duodenum (exocrine)
Releases bicarbonate to neutralise content from the stomach as it enters small intestine

Question 17

What does the large intestine do?

Answer 17

Absorbs water and electrolytes from undigested food to form faeces
Houses bacteria that ferments fibre and produces vitamins

Question 18

What does the rectum do?

Answer 18

Stores faeces and excretes out anus

Question 19

What is pancreatitis?

Answer 19

Inflammatory process damages pancreatic tissue and can block ducts
Caused by alcohol, obesity, infection, trauma, medications, gall bladder issues
SX: pain with eating that radiates into the back, n+v, weight change, bowel change, fever

Question 20

What is gastritis?

Answer 20

Inflamed stomach lining
Caused by infection, NSAID, alcohol, stress, autoimmune
SX: pain, n+v, indigestion, bloat, reduced appetite

Question 21

What are the 4 stages of digestion?

Answer 21

Mechanical - teeth grind, bolus formed, chyme mixed
Chemical - enzyme and chemical
Absorption - villa absorb into blood
Elimination

Question 22

What is chemical digestion?

Answer 22

Enzyme or chemical action
Saliva has amylase to break down carbohydrate into sugars
Stomach has HCl and pepsin to break down protein into peptides
Pancreas secretes amylase, lipase and protease
Bile breaks down fat

Question 23

Describe the abdomen

Answer 23

Between diaphragm and pelvic brim
Lined with two layered peritoneum
Outer parietal layer adhered to wall
Inner visceral layer wraps around organs
Organs attached to rear wall via mesentery (also has vessels, fat and nerves)
Retroperitoneal at posterior side
Quadrants divide space into four

Question 24

What are macronutrients?

Answer 24

Fatty acids, carbohydrates and proteins

Question 25

What are carbohydrates?

Answer 25

Chains of C, O and H that the body uses for energy
Generally sugars, starches and fibre
Monosaccharides are simple sugars used for energy (glucose)
Disaccharides (lactose)
Polysaccharides are complex sugars which undergo hydrolysis before being used for energy

Question 26

What are fatty acids?

Answer 26

Used for energy, hormones, supports vitamins, builds cell membranes
Saturated and unsaturated

Question 27

What is protein?

Answer 27

Chains of amino acids and peptide bonds that the body uses for energy, growth and repair

Question 28

What are micronutrients?

Answer 28

Vitamins (fat soluble are D, E, K, A)
Minerals - macro and trace

Question 29

Which organs regulate BSL?

Answer 29

Liver
Pancreas
Muscle

Question 30

Describe the process of BSL control

Answer 30

Food is consumed and GI breaks down carbohydrates into glucose which is absorbed into the blood stream in the small intestine raising the BSL

Pancreas beta cells release insulin to move glucose into cells. It also promotes the liver to store glucose as glycogen and stops the liver from producing glucose itself. The BSL eventually drops

When BSL low again, pancreas alpha cells release glucagon which stimulates liver to release stored glycogen as glucose and BSL rise again

Question 31

What is glycogenolysis?

Answer 31

The process of glycogen being converted to glucose

Question 32

What other hormones may influence BSL?

Answer 32

Cortisol, adrenaline and growth hormone can increase BSL during stress, exercise or fasting via triggering gluconeogenesis

Question 33

What is gluconeogenesis?

Answer 33

Process of the liver producing glucose from a non-carbohydrate source

Question 34

What is normal BSL?

Answer 34

4.0-8.0 mmol

Question 35

What is cellular respiration?

Answer 35

Process of cells converting glucose into ATP
1. Glycolysis: glucose converted into pyruvate (in cytoplasm)
2. Citric Acid / Krebs Cycle: pyruvate converted into electrons (in mitochondria)
3. Oxidative Phosphorylation / Electron transport chain: electrons passed down protein chain releasing energy and chemiosmosis occurs (in mitochondria)

Question 36

What is the cellular respiration equation?

Answer 36

Glucose + O2 —> CO2 + water + ATP

Question 37

How do paediatrics digestive system differ?

Answer 37

Reduced ability to store glucose so become hypoglycaemic more rapidly
High metabolic rate needs plenty of glucose
Oesophageal sphincter has reduced tone so high incidence of regurgitation

Question 38

How does the geriatric digestive system differ?

Answer 38

Reduced oesophageal sphincter = reflux
Reduced GI mobility = constipation and reduced appetite
Weak stomach lining = prone to ulcer
Weak colon lining = diverticulitis
Reduced absorption = malnutrition

Question 39

What is appendicitis?

Answer 39

Inflamed appendix
Caused by blockage or lymphoid follicle
SX: lower right quadrant pain worsens with strain, low appetite, n+v, fever, bowel change, distension

Question 40

What is a GI bleed?

Answer 40

Any bleed from the digestive tract
Multiple causes
SX: hematemesis (bloody vomit), melena (dark stool), hematochezia (bright red stool), pain, fatigue, pale, dizzy, low BP, high HR