2.3. GI System

Question 1

Functions of mouth

Answer 1

• Ingestion of food
• Mechanical breakdown- food mixes with saliva containing enzymes
• Carries food through the pharynx and oesophagus to stomach

Question 2

Functions of oesophagus

Answer 2

• Moves food from mouth to stomach

- Food propulsion accomplished by deglutition (peristalsis)

Question 3

Function of liver

Answer 3

• Secretes bile which emulsifies fats by breaking down into smaller pieces

Question 4

Function of gallbladder

Answer 4

stores bile

Question 5

Functions of stomach

Answer 5

• Mechanical breakdown of food by peristalsis

- Protein digestion occurs here, by hydrochloric acid and pepsin

Question 6

Functions of pancreas

Answer 6

• Secretes digestive enzymes

- Supplies enzymes that digest chyme and bicarbonate that neutralise HCL

Question 7

Function of small intestines

Answer 7

• Digestion is completed and virtually all absorption occurs (microvilli, villi, circular folds)

Question 8

Functions of large intestines

Answer 8

• Absorb remaining water from indigestible food residues
• Stores residues temporarily
• eliminate them from the body as semisolid feaces

Question 9

Function of anus

Answer 9

• The opening at the end of the GI that allows faeces to leave the body

Question 10

Explain difference between peristalsis and segmentation

Answer 10

Peristalsis primarily propulsive whereas, segmentation is the mixing of food.
Peristalsis occurs all the way from oesophagus to large intestine but segmentation only occurs in the small intestine.
Food is moved distally in peristalsis and forwards then backwards in segmentation.

Question 11

General GI tract in pregnancy

alteration, significance/physiology, effect of which hormone

Answer 11

• Appetite increases, cyclical patterns of appetite, cravings and aversions
• hCG, leptin, oestrogen, progesterone

Question 12

Mouth in pregnancy

alteration, significance/physiology, effect of which hormone

Answer 12

• Gums become hyperaemic, oedematous (fluid filled) and spongy. Saliva becomes more acidic
• Oestrogen increases blood flow to the gums and changes the connective tissue consistency. This makes the gums more vulnerable.

Question 13

Oesophagus in pregnancy

alteration, significance/physiology, effect of which hormone

Answer 13

• Heartburn

- Progesterone relaxes the lower sphincter, causing a back flow of partially digested food and stomach acid.

Question 14

Stomach in pregnancy

alteration, significance/physiology, effect of which hormone

Answer 14

• Acid secretion decreases, secretion of pepsin falls, decreased gastric motility
• Slow emptying of stomach, increased pulping of food, nausea, delay absorption of glucose
• Progesterone

Question 15

Small/large intestine in pregnancy

alteration, significance/physiology, effect of which hormone

Answer 15

• Gut tone and motility decreases, abdominal distension, constipation, increased iron absorption, raised levels of angiotension and aldosterone
• Progesterone relaxes smooth muscle- increased water absorption. Duodenal villi enlarge. Increase in sodium and water absorption from colon- increased flatulence.

Question 16

Gallbladder in pregnancy

alteration, significance/physiology, effect of which hormone

Answer 16

• Flacidity, increased bile storage but decreased emptying rate
• Bile contains less cholesterol because water resorption by epithelium cells is decreased
• Progesterone affects smooth muscle tone

Question 17

Liver in pregnancy

alteration, significance/physiology, effect of which hormone

Answer 17

• Hepatic displacement- due to gravid uterus
• Increased glycogen and triglyceride storage
• Decrease in albumin (due to plasma volume expansion), increase in fibrinogen and increased cholesterol synthesis
• Increased hepatic perfusion- increase in portal venous return
• Oestrogen

Question 18

What are some theories given for causes of NVP?

Answer 18

1. Evolutionary mechanism: protects embryo by causing woman to physically expel and avoid foods which may contain teratogenic and abortifacient chemicals.
2. Stimulates early placental growth: reduces maternal energy intake and suppresses maternal tissue synthesis so nutrient partitioning favours placenta.
3. hCG peaks in 1st trimester

Question 19

What is HYPEREMESIS GRADIVARUM?

What signs and symptoms indicate it?

Answer 19

Severe and persistent nausea and vomiting which leads to nutritional deficiencies .
May require hospitalisation to correct the electrolyte and fluid imbalances.

Question 20

What are some known risk factors of HG?

Answer 20

• Previous HG
• Hyperthyroid disorders
• Pre-existing psychiatric disorders
• Molar pregnancy
• GI disorders
• Multiple gestation with a female and male twin