digestive system

Question 1

Name and explain the 6 digestive properties

Answer 1

1. Ingestion- the taking in food via mouth
2. Propulsion- moves the food along the GI tract, including swallowing which is voluntary, and peristalsis which is involuntary
3. Mechanical digestion;
   - chewing: mixing food with saliva by the tongue
   -churning- food in the stomach
   - segmentation: mixes food with digestive enzymes
   - increases the efficiency of absorption
4. Chemical digestion-
   complex food molecules are broken down into their monomers by enzymes which are secreted into the lumen of the canal
   begins in the mouth and ends in the SI.
5. Absorption-passage of digested end products from the lumen of the GI tract through the mucosal cells into the blood or lymph
6. Defecation- eliminates indigestible wastes from the body via the anus in the form of faeces

Question 2

Inorder to initiate chemical digestion what must happen?

Answer 2

Teeth will stimulate the salivary glands to secrete saliva to being CD

Question 3

Why is it important that the epiglottis covers the glottis and direct the bolus into the oesophagus? What is a bolus?

Answer 3

The tongue shapes the food into a bolus and during swallowing pushes the bolus back to the oral cavity. It is important the epiglottis covers the glottis because we have 2 tubes one that leads the food into the stomach and the second is our breathing tube. If food is in our breathing tube the person would chock and leading them to had difficulty breathing;

Question 4

list the sphincters and where do they lead to

Answer 4

Gastroesophageal sphincter- controls food entry into the stomach
pyloric sphincter- chyme is passed via the pyloric sphincter leading to the small intestine specifically to the duodueum

Question 5

How does the stomach wall withstand a pH2, which is considered to be highly corrosive?

Answer 5

Mucus protects the stomach lining from HCl and pepsin

Question 6

What is the function of the stomach?

Answer 6

Protein digestion

Question 7

The liver carries out a number of digestive activities . Which is a characteristic function of the liver?

Answer 7

Bile formation

Question 8

Which organ secretes digestive enzymes that are capable of breaking down the 4 main biomolecules; proteins, DNA, lipids and carbohydrates?

Answer 8

The pancreas

Question 9

Carbohydrates are digested by enzymes into monosaccharides. What enzyme is responsible for carbohydrate digestion?

Answer 9

Amylase

Question 10

Gallbladder stores the bile what is another function of the Gallbladder?

Answer 10

acts as detergents that aid in digestion and absorption of lipids- emulsification

Question 11

Distinguish between absorption in the small intestine and absorption in the large intestine.

Answer 11

In the small intestines - the jejunum and ileum mostly function in the absorption of water and nutrients (fructose, amino acids, fatty acids peptides)
In the large intestine- functions in the recovery of water by osmosis

Question 12

How do villi and microvilli play a role in the small intestine?

Answer 12

They increase the surface are for the absorption and for substances to move.

Question 13

How is faeces released?

Answer 13

By the anal sphincter