3.4 Digestive System in Animals

Question 1

Label the parts of the digestive system

Answer 1

Question 2

What is mechanical digestion achieved?

Answer 2

Mechanical digestion is achieved through chewing and the churning motion of the stomach.

Question 3

What does the digestive system do?

Answer 3

The digestive system breaks down macromolecules: proteins, carbohydrates, lipids (fats) into smaller sub-units that can be absorbed and used for energy production, growth, maintenance and repair.

Question 4

In terms of structure what are the two main components of the digestive system?

Answer 4

1) Alimentary canel (gut) essentaily a open tube and consists of halow organs.

2) Accessory organs These solid organs release secretions, including enzymes, that are delivered via ducts into the lumen of the alimentary canal.

Question 5

Why is food broken down into smaller pieces?

Answer 5

Breaking down food into smaller pieces produces an increase in its surface area. As a result, chemical digestion through enzyme action occurs more rapidly on these small food pieces than would occur if the pieces of food were larger.

Question 6

What is chemical digestion and how is it achieved?

Answer 6

Chemical digestion is when Macromolecules of food are broken down to smaller and smaller sub-units through the action of enzymes.

Question 7

What does lumen mean?

Answer 7

Inside of a hallow tube.

Question 8

What four tissues form the gut wall and name there order of arrangement?

Answer 8

1)Mucosa epithelial tissue forms the innermost lining of the digestive system, and it is part of the first tissue layer .

2)Sub-mucosa connective tissue forms this second layer, and it includes blood vessels, lymphatic vessels and nerves.

3) Muscular is muscle tissue forms the third layer of the gut wall.

4)Serosa connective tissue forms the fourth and outside layer that encloses the gut

Question 9

What is the difference between simple epithelium
and stratified epithelium?

Answer 9

Simple epithelium is composed of a single layer of cells.

Stratified epithelium is composed of two or more layers of cells

Question 10

What are the three simple types of epithelial tissue and two stratified.

Answer 10

Question 11

What type of epithelium tissue is found in the oesophagus?

Answer 11

in the oesophagus, the epithelium is stratified and squamous

Question 12

What type of epithelium tissue is found in stomach?

Answer 12

in the stomach, the epithelium is simple columnar and smooth with many infoldings (crypts)

Question 13

What type of epithelium tissue is found in the small intestine?

Answer 13

in the small intestine, the epithelium is simple columnar with many outfoldings (villi) and infoldings (crypts).

Question 14

What are the functions of epithelial tissue in the alimentary canal?

Answer 14

The functions of the epithelial tissue of the alimentary canal include protection, absorption and secretion.

Question 15

What is the function of the connective tissue in the hallow organs of the alimentary canal?

Answer 15

Connective tissue in the hollow organs of the alimentary canal provides structural support to other tissues. For example, the connective tissue of the sub-mucosa of the gut wall supports the overlying mucosa and connects it to the underlying muscularis

Question 16

What is amylase and what does it do?

Answer 16

Amylase is an enzyme that plays an important role in the digestion of carbohydrates. It is produced in the pancreas and salivary glands and helps to break down complex carbohydrates such as starch and glycogen into simpler sugars such as glucose, maltose, and fructose.

In the mouth, salivary amylase starts the process of carbohydrate digestion by breaking down starch into maltose. Once the food reaches the small intestine, pancreatic amylase takes over and continues to break down the remaining complex carbohydrates into simple sugars that can be absorbed into the bloodstream.

Question 17

What is trypsin and what does it do?

Answer 17

Trypsin is a digestive enzyme that is prooduced in the pancreas and secreted into the small intestine, where it helps to break down proteins into smaller peptides and amino acids.

Question 18

Why are enzymes important in the digestive system?

Answer 18

enzymes are required in the digestive system to break down complex molecules into simpler molecules that can be absorbed and utilized by the body. The food we eat contains macromolecules such as carbohydrates, proteins, and lipids, which are too large and complex to be directly absorbed into the bloodstream.

Enzymes such as amylase, protease, and lipase are secreted by the pancreas and other glands in the digestive system to break down these macromolecules into smaller molecules such as simple sugars, amino acids, and fatty acids, which can be absorbed through the small intestine into the bloodstream.

Without enzymes, the digestive system would not be able to extract nutrients from food and provide the body with the energy and building blocks it needs to function properly. Therefore, enzymes are essential for the proper functioning of the digestive system and overall health.

Question 19

What is lipase and what is its function?

Answer 19

Lipase is an enzyme that plays a key role in the digestion and metabolism of fats (lipids) in the body. Lipase is produced in various organs, including the pancreas, liver, and small intestine.

In the digestive system, pancreatic lipase is secreted by the pancreas and breaks down fats into fatty acids which can then be absorbed by the body.

Question 20

List the order of organs by which food passes through.

Answer 20

1)Mouth
2)Oesophogus
3) Stomach
4)Small intestine
5)Large intestine
6) Rectum

Question 21

Function of mouth during digestion of food.

Answer 21

Mouth: Mechanical and chemical digestion starts food is chewed and mixed with saliva, which contains enzymes such as salivary amylase that start to break down carbohydrates and lingual lipase which starts digestion of fats.

Question 22

What two glands are located in the mouth?

Answer 22

salivary glands that secrete a watery saliva that contains the carbohydrate-digesting enzyme, amylase

lingual glands on the surface of the tongue that secrete the fat-digesting enzyme, lipase.

Question 23

Why is muscle tissue at the top end of the oesphagus and rest of muscle tissue of oesophagus responsible for?

Answer 23

The muscle tissue in the esophagus is smooth muscle (waves of this muscle move the food forward) which is responsible for the involuntary movement of food through the digestive track. However, there is a small segment of striated muscle tissue located at the upper end of the oesophagus because the striated muscle tissue in this region of the esophagus is part is under voluntary control, which allows us to initiate the swallowing process

Question 24

What happens in the oesophagus during digestion?

Answer 24

In the process of digestion the food is transported to the stomach via the esophagus through a process called peristalsis which involves a zone of muscle contraction immediately above the food and a zone of muscle relaxation immediately below the food which allows the food to be pushed forward towards the stomach. This process is also aided by muscus which lubricates the walls of the esophagus and helps food move more easily.

Question 25

Why can someone swallow food upside down?

Answer 25

Because the movement of food down the osephogus is due to muscular action of the oesophagus and not gravity thus a person can swallow food while upside down.

Question 26

What folds in the stomach wall allow it to expand?

Answer 26

This ability of the stomach to expand is due to the presence of folds (called rugae) in the stomach wall.

Question 27

What happens in the stomach during the digestion of food (Hint MAE)?

Answer 27

The stomach is an important organ in the digestive system, where several key processes occur during digestion:

-Mixing and Grinding: The stomach muscles contract and mix the food with digestive juices, breaking it down into a thick liquid called chyme and mechanical digestion also occur when this is happening through stomach’s muscular walls which grind the food, helping to further break it down into smaller pieces.

Acid Secretion: The stomach lining secretes hydrochloric acid (HCl) to help break down proteins . The acidic environment also helps to kill any harmful bacteria that may be present in the food.

Enzyme Secretion: The stomach lining also secretes digestive enzymes, including pepsin, which breaks down proteins into smaller peptides and and gastric lipase which breaks down fats.

After all this the stomach slowly releasing chyme into the small intestine for further digestion and nutrient absorption.

Question 28

What secretory cells do the gastric glands of the stomach include (hint 2 and activation).

Answer 28

parietal cells that secrete hydrochloric acid, which creates the acid conditions of the stomach (pH 2–3)

chief cells that secrete the enzyme gastric lipase and the inactive proenzyme,pepsinogen. In the acidic conditions of the stomach, pepsinogen is converted to the active enzyme pepsin where it begins the digestion of proteins.

Question 29

What are ducts?

Answer 29

Ducts are channels or tubes that carry fluids or substances from one part of the body to another.

Question 30

What is the function of the liver in digestion?

Answer 30

The function of the liver is to secrete bile a fluid which contains bile salts which aid in the assistance of digesting fats by emulsifying fat molecules into smaller droplets , bile transferred to the gall ballder via small ducts where it is either stored or released into the duodenum.

The liver is responsible for removing toxins, drugs, and other harmful substances from the blood.

Question 31

Why are the gallbladder and liver so close together?

Answer 31

The liver and gallbladder are closely located because they are both part of the biliary system, which is responsible for producing and storing bile , liver produces bile gall bladder stores it.

Question 32

What is the function of the pancreas in the digestive system?

Answer 32

Its main functions are to produce pancreatic juice which contains digestive enzymes.

The digestive enzymes produced by the pancreas are released into the small duodenum to help break down carbohydrates, proteins, and fats into smaller molecules that can be absorbed by the body. These enzymes include amylase, protease, and lipase, which respectively break down carbohydrates, proteins, and fats.

Question 33

What are the 3 parts of the small intestine (hint think um)?

Answer 33

1) Duodenum
2)jejunum
3)Ileum

Question 34

By the presence of what 3 things in the mucosa of the small intestine makes it different from the mucosa of other organs?

Answer 34

Villi , Microvilli , Crypts

Question 35

What are microvilli , villi and crypts?

Answer 35

Villi are finger-like structures that project into the lumen of the small intestine; villi are covered by absorptive cells (enterocytes) and mucus-secreting goblet cells.

Crypts are narrow depressions that descend into the mucosa and they are intestinal glands

Microvilli are minute outfoldings of the plasma membranes of enterocytes

Question 36

Why does the epithelial surface of small intestine have such a great surface area compared to a object of similar dimensions ?

Answer 36

3

Question 37

What happens in the small intestine during digestion?

Answer 37

As food enters the small intestine, it is mixed with digestive enzymes; amylase , lipase and trypsin ( actually trypsinogen than converted) which are found in the pancreatic juice received by the small intestine and bile from the liver and gallbladder his also mixed. Enzymes break down carbohydrates, proteins, and fats into smaller molecules so that they can be absorbed by the body. Bile, which is produced in the liver and stored in the gallbladder, helps to emulsify fats, making them easier to digest and absorb.Absorption of the end products of digestion is a function of the enterocytes that line the small intestine and its villi.

Question 38

What is the function of the large intestine in the digestive systyem?

Answer 38

The large intestine, also known as rectum , anus and colon , is the final part of the digestive system. Its main functions are to absorb water and electrolytes from undigested food matter, store fecal matter, and facilitate the elimination of waste from the body.

The large intestine receives undigested food material from the small intestine. As the material passes through the colon, water and electrolytes are absorbed into the bloodstream, leaving behind a more solid waste material called feces. The feces are stored in the rectum until they are eliminated from the body during a bowel movement.

Question 39

Specialised cells that synthesise enzymes to aid in the digestion of food can be found in the walls of the:

Answer 39

Stomach