Chapter 7 - The Lungs & Alimentary Canal

Question 0

What’s the purpose of the continuous flow of blood?

Answer 0

It helps to maintain a difference in concentrations of oxygen and carbon dioxide in the blood and in the air in the lungs.

Question 1

Why does the alveoli have a large surface area?

Answer 1

So that large amounts of gases can be exchanged in a relatively short time.

Question 2

Why is the membrane of the alveolus very thin?

Answer 2

So that gas molecules do not have far to travel to move into or out of the blood.

Question 3

Why are the lungs positioned deep inside the body?

Answer 3

To prevent excessive evaporation of the fluid that covers the respiratory surfaces.

Question 4

What is the purpose of constant changing of the air in the alveoli?

Answer 4

It helps to ensure that there is always a difference in the concentrations of oxygen and carbon dioxide in the air and in the blood.

Question 5

What is Ventilation?

Answer 5

The process by which air is moved into and out of the lungs.

Question 6

How idea Inspiration/Inhalation work?

Answer 6

For air to flow into the lungs, the pressure of air in the lungs must be less than the atmospheric pressure outside the body. This is achieved by increasing the volume of the lungs.

Question 7

How to increase the volume of the lungs?

Answer 7

The diaphragm and external intercostal muscles contract, it thus become flatter and the rib cage moves upwards and outwards, increasing the volume of the chest cavity.

Question 8

What is Pleura?

Answer 8

Membrane around the lungs.

Question 9

How does Expiration/Exhalation take place?

Answer 9

The diaphragm and external intercostal muscle relax so that the diaphragm bulges more into the chest cavity and the rib cage moves downwards.

This reduces the volume which increases the air pressure in the lungs.

Question 10

What is the concentration of Oxygen like in the blood that comes into the capillaries around the alveoli?

Answer 10

Low concentration of Oxygen than the air in the alveolus.

Question 11

What is the concentration of carbon dioxide like in the alveolar capillaries?

Answer 11

It has a higher concentration than the air in the alveolus

Question 12

How is the concentration gradient for oxygen and carbon dioxide maintained?

Answer 12

•The constant blood flow through the capillaries. As the blood flowing through the capillaries around each alveolus picks up oxygen and loses carbon dioxide it is replaced by more blood pumped into the capillaries. This ‘new’ blood is low in O2 and high in CO2 so that the concentration gradient is maintained.

Question 13

What is the Alimentary Canal?

Answer 13

It is the continuos tube that runs from the mouth to the anus.

Question 14

What are the 6 basic activities carried out by the Digestive System?

Answer 14

1. Ingestion of food and water
2. Mechanical digestion of food
3. Chemical digestion of food
4. Movement of food along the alimentary canal
5. Absorption of digested food and water into the blood and lymph
6. Elimination of material that is not absorbed.

Question 15

What does the big Intestine consist of?

Answer 15

Transverse, Ascending and Descending colons. They are the longest part of large intestine. Absorbs water, minerals, vitamins.

Question 16

What is the main purpose of the Mouth?

Answer 16

• Breaks food into smaller particles by chewing.

* Saliva, which contains salivary amylase, begins starch digestion.

Question 17

What is the main purpose of the Oesophagus?

Answer 17

It carries food from the mouth to the stomach.

Question 18

What are the functions of the Stomach?

Answer 18

• Waves of contraction churn food.

* Gastric juice, which contains pepsin, breaks down proteins to polypeptides.

Question 19

What are the functions of Small intestine?

Answer 19

•Muscular contractions churn food; bile salts emulsify lipids.

•Pancreatic juice- contains: pancreatic amylase, which breaks starch into disaccharides; pancreatic protease, which breaks proteins and polypeptides into peptides; pancreatic lipases, which break down lipids into fatty acids and glycerol; and nucleases, which digest DNA
and RNA.

•Intestinal juice - contains amylase a to break down disaccharides to simple sugars; peptidases to break down peptides to amino acids; and lipases to break down lipids to fatty acids and glycerol.

Question 20

What are the 4 Incisors for?

Answer 20

These are chisel-shaped teeth used for biting or cutting, such as when on takes a bite out of an apple.

Question 21

What are the two Canines for?

Answer 21

Located one on each side of the incisors, these are conical teeth used for tearing.

Human canines are the same length as the other teeth.

Question 22

Where are the four Premolars located?

Answer 22

There are two on each side of the jaw.

Question 23

What are the 6 molars for?

Answer 23

Three on each side of the naw, the premolars and molars have broad crowns with rounded cusps. The cusps of the teeth of one jaw fit into depressions on the surface of teeth on the other jaw, making the premolars and molars ideal for crushing and grinding,

Question 24

Where is the food brought to after chewing?

Answer 24

The pharynx leads into the Oesophagus.

Question 25

What is the function of the Mucosa?

Answer 25

It is specialized for the secretion of gastric juice, a digestive juice that is responsible for digestion in the stomach.

Question 26

What is the function of the Gastric juice?

Answer 26

It is secreted by gastric glands which are located in narrow, tube-like structures called gastric pits. It contains Hydrochloric Acid, Mucus and digestive enzymes.

Question 27

What is the purpose of the Plyoric Sphincter?

Answer 27

The constriction is sufficient to prevent the stomach contents moving through useless pushed along by peristalsis.

Question 28

What is the first part of the small intestine?

Answer 28

Duodenum

Question 29

Substances involved in the small intestine.

Answer 29

• Intestinal juice - glands in the lining
• Pancreatic juice - pancreas
• Bile - liver but stored in the gall bladder

Question 30

List the Enzymes involved in digestion of food that are contained in the pancreatic juice.

Answer 30

• Pancreatic Amylase - starch
• Trypsin (Pancreatic Protease) - proteins
• Ribonuclease and Deoxyribonuclease - RNA and DNA
• Pancreatic Lipases -fats and glycerol.

Question 31

Why are Bile Salts important?

Answer 31

They act like a detergent and emulsify fat, breaking if into ting droplets.

Question 32

List the ways to achieve a large internal surface area.

Answer 32

• The small intestine is very long
• The inner lining, known as the mucosa, had folds that extend into the interior
• The mucosa has finger-like projections called villi that extend from the folded surface.
• The cells covering the outside of the villi have tiny microscopic projections from their external surfaces; microvilli

Question 33

How is the structure of the villus ideally suited to its function of nutrient absorption?

Answer 33

•Contains a lymph capillary called the Lacteal, which is surrounded by a network of blood capillary.

•continual movement of villi brought about by the muscular movements of the intestinal wall.
=This constantly brings the villi into contact with different parts of the intestinal contents.

• Simple diffusion, as there is a higher concentration of nutrient materials in the interior of the small intestine than in the cells lining the villi.
• Active transport

Question 34

What are absorbed by the blood capillaries from the Villi walls?

Answer 34

Simple sugars, Amino acids, water and water-soluble vitamins are absorbed into the blood capillaries.

Question 35

How is fat formed?

Answer 35

Fatty acids and glycerol recombine in the cells of the villi to form fats and, along with fat soluble vitamins, enter the Lacteal.

Question 36

There are NO villi in the large intestine.

True/False?

Answer 36

True

Question 37

Large intestine secrete digestive juices. True/False?

Answer 37

False.

The lining does secrete a large amount of mucus.

Question 38

What happens in the Large Intestine?

Answer 38

Movements of material is fairly slow, most of the remaining water is absorbed so

Question 39

What does the bacteria in the Large Intestine do ?

Answer 39

It breaks down much of the remaining organic compounds. Some bacteria produce vitamin, which are then absorbed through the walls into the blood. Mineral nutrients are absorbed.

Question 40

Define Excretion.

Answer 40

The removal of metabolic waste, waste that has been produced by chemical activity of the body cells.