Digestive System And The Alimentary Canal Flashcards
What are the disorders of the digestive system?
* Malnutrition
* Obesity
* Tooth decay
* Diabetes
* Constipation
* Ulcers
* Diarrhoea
* Bowel habits
* Anorexia nervosa
* Liver Cirrhosis
What is malnutrition?
There are two types. It is a condition resulting from a lack of nutrients that are required for a healthy growth. Nutrients are lacking or too high in quantities or wrong proportions
What is overnutrition?
Too much food is consumed. For example diabetes and obesity
What is under nutrition?
Too little food is consumed
What is obesity?
A medical condition of having excessive amount of body fat caused eating too much or little exercise
What is tooth decay?
Too much sugar intake and poor oral hygiene
What is type two Diabetes?
Occurs when the body is not able to control the amount of sugar in the blood.
What is type two diabetes caused by?
Can be inherited
Caused by eating too much sugar
Living an inactive lifestyle
What is constipation?
A condition in which bowel movements occur less frequently and consists of hard and dry stools. Stools become hard and are difficult to pass
When does constipation occur?
When one does not consume enough fibre and little water
What can chronic constipation lead to?
It leads to haemorrhoids and colon cancer
What are ulcers?
Sores in the lining of the mouth and intestines. It is the result of wounds that do not heal properly. May be vitamin C deficiency. Breaks in skin or mucus in membrane. Stomach, mouth and intestines.
What is diarrhoea?
A condition where a person has more than five bowl movements of watery stools per day
What can diarrhoea be caused by?
Artificial sweeteners and other additives
Define additives
Chemical substances that make food last longer and add flavour
What can eating large meals lead to?
A change in bowel habits. The urge to have bowel movements does not happen
What is another name for the alimentary canal?
The gastrointestinal tract
What is the digestive system?
Made up of all the organs that play a role in digestion. It includes the alimentary canal and the liver
Define alimentary canal
The structures that food passes through. Food needs to be broken down into smaller particles
How many processes take place in the digestive system?
4 processes
What are the process of the digestive system?
Ingestion, digestion, absorption and egestion
What is ingestion?
The intake of food by biting, chewing and swallowing. It occurs in the mouth
What is digestion?
Mechanical and chemical process that converts large complex insoluble foods into simple soluble nutrients. Break down of food into a form that can be absorbed. Occurs in stomach and small intestine
What is absorption?
Occur when soluble nutrients are taken up by the bloodstream.
How are nutrients and water dissolved in absorption?
By diffusion
What happens in the small intestine during absorption?
Good particles are broken down by digestion and are ready to be absorbed. Inner wall of small intestine
What happens with the villi and absorption?
Inner wall of small intestine is covered with millions of small villi (finger like projection). Villi contain blood vessels which absorb the digested nutrients. Nutrients are now transported into bloodstream to blood cells
What is egestion?
Occurs when undigested food materials called faeces are passed out of the body through the anus. Ingested food from alimentary canal
What are the digestive organs?
- Mouth
- Pharynx
- Oesophagus
- Stomach
- Duodenum
- Small intestine
- Large intestine
- Rectum
- Anus
What process of digestion takes place in the mouth?
Ingestion
What happens in the mouth?
Teeth and tongue crash and mash food. The mouth helps to mix the food with saliva and swallow
Define saliva
Liquid secreted into the mouth by salivary glands
What are the functions of the mouth?
- Teeth break down the food into smaller pieces, which increases the surface area for attachment of chemicals, which further digest food
- Tongue and palate rolls to eat food into a small ball which is called Bollus. This makes swallowing easier
What happens in the pharynx?
Common area for both the digestive and respiratory system
What happens in the oesophagus?
Walls of the oesophagus and the rest of the canal a build up of muscle layers. The muscle layers contract and relax rhythmically in order to push food through the elementary canal. This movement is called peristalsis. It is a muscular tube that runs from the mouth to the stomach
Define pertistalsis
Rhythmic contraction of the muscle layers in the digestive canal that push food forward
What are the functions of the oesophagus?
- Transport food from the mouth to the stomach in the process of peristalsis
What happens in the stomach?
Thick muscular walls contract in turn the stomach contents. It is a muscular organ. Movement break up the food into smaller parts for enzymes. It is secreted by the lining of the elementary canal to help break down food
What process of diegstion takes place in the stomach?
Digestion
Define enzymes
Proteins that speed up the rate of chemical reactions
What is the function of the stomach?
- Peristalsis occurs in many different directions. This further breaks down food
- Complex in soluble food converted into simple soluble substances
What processes of digestion takes place in the small intestine?
Digestion and absorption
What happens in the small intestine?
- Intestinal glands secrete intestinal juice which contains different enzymes. The enzymes break down the food into substances that can be absorbed.
- Walls are lined with millions of violet that absorb nutrients.
- It is a long muscular tube
What is the function of the small intestine?
- Digestion is completed here
- Absorption occurs here and absorbs the nutrients
What happens in the large intestine and the colon?
- Absorbs water from waste back into the blood. Waste material becomes more compact and form stores or faeces
- Mucus glands secrete mucus that makes the store smooth and easily removed
- Colons store waste before egested
- The rectum is the last part
What is the function of the large intestine?
- Nutrients and water are absorbed
- Faeces temporarily stored in the rectum
What happens in the liver?
- Largest gland in the body
- Break down substances to form bile which assist in digestion process and stored in gallbladder
What’s process of digestion takes place in the large intestine?
Absorption
What happens in the rectum?
Stores are temporarily stored before egested
What happens in the anus?
End opening of the digestive system. Wastes are egested. Opening through which faeces leave the body
What process of digestion takes place in the anus?
Egestion
Define diffusion
A process during which substances (nutrients) move from a region of high concentration to a region of low concentration until equilibrium is reached
Define assimilation
Dissolved nutrients into the cells by diffusion
Where do you nutrients move from and to and during diffusion?
Nutrients move from the small intestine into the blood capillaries by diffusion during absorption
What are the two types of digestion?
Mechanical and chemical digestion
Define mechanical digestion
Large food particles are mechanic be broken down into small pieces. It is large insoluble complex substances to small substances. It is the physical breakdown of food by crushing, mashing and churning
Where does mechanical digestions take place?
It takes place in the mouth, oesophagus, stomach and small intestine
What happens in the mouth in terms of mechanical digestion?
The teeth physically break down crush and mash food. Tongue pushes food under the teeth and answer the palate which breaks food into small pieces
What happens in the oesophagus in terms of mechanical digestion?
Peristalsis occurs here. It is contraction and relaxation. Pastel take wave takes place
What takes place in the stomach in terms of mechanical digestion?
Turning movement of walls break down the food into smaller pieces. Peristalsis occur is here and it occurs in all directions. The Paris Deltic movement in the alimentary canal pushes the food forward and helps break down the food even further
What takes place in the small intestine in terms of chemical digestions?
The bile breaks down fats into smaller droplets
What is the function of mechanical digestion?
Breaks down food into smaller pieces
What is the significance of mechanical digestion?
- The surface area is increased as it breaks down the food into smaller pieces
Does the increase of area of nutrients make chemical digestion more efficient?
- Faster process
- More product is produced
Define chemical digestion
Small particles are chemically altered into nutrients. Breakdown of food into nutrients by means of chemical reactions which is broken down by enzymes
What happens to the food during chemical digestion?
Insoluble food into simple soluble nutrients
Where does chemical digestions take place?
It takes place in the mouth, stomach and small intestine
What happens in the mouth in terms of chemical digestions?
Saliva re gland secrete saliva which contains enzymes which breaks down starch and therefore chemical digestions starts
What happens in the stomach in terms of chemical digestion?
Hydrochloric acid is a digestive juice secreted by glands in the lining of the stomach. It contains enzymes which chemically out of food particles in the substances that are soluble in water and unable to be a absorbed into the bloodstream
Define soluble
Nutrients dissolved in water
Why does the nutrients in the stomach have to be soluble?
It needs to be soluble as it cannot get into the cells
What do enzymes speed up the conversion of?
Enzymes speed up conversions of complex in soluble substances into so simple soluble nutrients
What takes place in the small intestine in terms of chemical digestion?
Enzymes are secreted by intestinal glands
Why is there such as a digestive system?
It breaks down food into dissolved nutrients which can be absorbed into the bloodstream and transported to the cells
Define nutrients
And ingredient which nourishes the body. For example glucose
What can stomach ulcers because by?
By bacteria
What is anorexia nervosa?
It is an eating disorder which causes people to obsess about the food they eat. It is the fear of gaining weight.
What does a person that suffers from anorexia nervosa do to maintain or loose weight?
They may starve themselves or exercise excessively
Define faeces
Waste material which is excreted through the anus
What can diarrhoea because by?
It may be caused by drinking water contaminated with bacteria
What is liver Cirrhosis?
It was the disease of the liver where the liver tissue is replaced with abnormal nodules or connective tissue
What is liver cirrhosis caused by?
Drinking too much alcohol
Why should digestion occur?
Break down food into a form that can be absorbed and soluble in water
What does increased surface area allow?
Increase surface area allows for greater attachment of enzymes for chemical digestion which makes chemical digestion more efficient
