7. Animal Nutrition Flashcards
Balanced Diet
consists of all of the food groups in the correct proportions for optimum body functions.
Which group of people require most calories
Adolescent males with active lifestyle
Constipation is caused by?
Lack of dietary fiber
Starvation
Suffering or death caused by lack of food
What is scurvy caused by?
Lack of vitamin C
2 Main groups of fiber
Soluble Fiber (Oats, Fruits) , Insoluble fiber (whole meal bread, Nuts).
Causes of Vitamin D deficiency
Not enough sunlight, No oily fish, egg yolk, or milk
Food Groups?
CPL MV DW Carbohydrates Proteins Lipids Vitamins Minerals Dietary Fibre Water
Food Groups (Picture)
Effect of Vitamin D Deficiency
Rickets in Children - due to malformed bones.
Reasons for Iron Deficiency
Diet lacking in Iron
Pregnancy
Blood Loss
Specific vitamin and mineral requirements: (Picture)
Malnutrition
is caused by not eating a balanced diet
different types of malnutrition
- Starvation
- Coronary heart disease
- Constipation
- Obesity
Effects of Malnutrition
Protein Energy Malnutrition
In many countries in the world, droughts, natural disasters, wars and a poor economy can lead to mass malnutrition in large areas of the country
The two types of malnutrition most common in these situations are termed ‘protein-energy malnutrition’ (PEM)and they are:
Kwashiorkor – caused by a lack of protein in the diet, most common in children under 2. Often caused by poverty as high protein foods tend to be more expensive and scarcer. Children suffering from kwashiorkor are always underweight for their age but they often have a swollen abdomen as their diet may contain a lot of carbohydrates
Marasmus – the most severe form of PEM, where there is a lack of both protein and energy in the diet. People suffering from this have a much lower body weight than normal and look emaciated
Dietary Needs of Different Individuals
5 different stages of Food Passage
I’M Carrying Ants And Elephants!!
- Ingestion
- Mechanical digestion
- Chemical digestion
- Absorption
- Assimilation
- Egestion
Ingestion?
the taking of substances, e.g. food and drink, into the body through the mouth
Mechanical digestion
- The breakdown of food into smaller pieces without chemical change to the food molecules
- It is mainly carried out by the chewing action of the teeth, the churning action of the stomach and the emulsification of fats by bile in the duodenum
Chemical digestion?
– the breakdown of large, insoluble molecules into small, soluble molecules
Absorption
the movement of small food molecules and ions through the wall of the intestine into the blood
Assimilation
the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells
Egestion
the passing out of food that has not been digested or absorbed, as faeces, through the anus
Structure & Function of the Alimentary Canal (Picture)
Diarrhoea?
- Diarrhoea is the loss of watery faeces from the anus
- If it is severe and continues for a long time, it can lead to death
- Severe diarrhoea can cause the loss of significant amounts of water and ions from the body, causing the tissues and organs to stop working properly
Causes of diarrhoea
There are many causes of diarrhoea, one of which is infection with Vibrio cholerae bacteria, which causes the disease cholera
How Does Vibrio Cholerae Cause Diarrhoea?
- Ingested via infected water or food, if it enters the small intestine it can cause illness in the following way:
- Bacteria attach to the wall of the small intestine
- They produce a toxin
- The toxin stimulates the cells lining the intestine to release chloride ions from inside the cells into the lumen of the intestine
- The chloride ions accumulate in the lumen of the small intestine and lower the water potential there
- Once the water potential is lower than that of the cells lining the intestine, water starts to move out of the cells into the intestine (by osmosis)
- Large quantities of water are lost from the body in watery faeces
- The blood contains too little chloride ions and water
Different Types of Teeth
- Incisors – chisel-shaped for biting and cutting
- Canines – pointed for tearing, holding and biting
- Premolars and molars – larger, flat surfaces with ridges at the edges for chewing and grinding up food
Structure of a Typical Tooth (Picture)
Plaque?
- Many bacteria live in the mouth and most are harmless, however some form a sticky film with saliva, called plaque, which coats teeth and the areas where they attach to gums
- To begin with, plaque is soft and easy to remove, however if it hardens and forms tartar, it cannot be removed by brushing
- Tartar around the edges of teeth and gums can allow bacteria to work their way into roots, causing gum disease and loss of teeth
Dental Health
- Reducing the amount of sugar eaten can prevent tooth decay
- Brushing teeth regularly removes the buildup of plaque that can cause gum disease and removes the sugars in the mouth so bacteria cannot turn them into acids and cause tooth decay
- Teeth should be brushed with a fluoride toothpaste as this helps to strengthen enamel and reduce damage from acids
- Regular visits to a dentist ensures that any signs of gum disease or tooth decay can be dealt with promptly
Purpose of digestion
- The purpose of digestion is to break down large, insoluble molecules (carbohydrates, proteins and lipids) into small, soluble molecules that can be absorbed into the bloodstream
- Food is partially digested mechanically (by chewing, churning and emulsification) in order to break large pieces of food into smaller pieces of food which increases the surface area for enzymes to work on
- Digestion mainly takes place chemically, where bonds holding the large molecules together are broken to make smaller and smaller molecules
three main types of digestive enzymes
Chemical digestion is controlled by enzymes which are produced in different areas of the digestive system
There are three main types of digestive enzymes
carbohydrases, proteases and lipases
Carbohydrase
- Amylase is secreted into the alimentary canal in the mouth and the duodenum (from the pancreas) and digests starch to maltose (a disaccharide)
- Maltose is digested by the enzyme maltase into glucose on the membranes of the epithelium lining the small intestine
Proteases
Protein digestion takes place in the stomach and duodenum with two main enzymes produced:
- Pepsin is produced in the stomach
- Trypsin is produced in the pancreas and secreted into the duodenum
Lipases
- Lipase enzymes are produced in the pancreas and secreted into the duodenum
- They digest lipids into fatty acids and glycerol
The Role of Hydrochloric Acid
- The stomach produces several fluids which together are known as gastric juice
- One of the fluids produced is hydrochloric acid
- This kills bacteria in food and gives an acid pH for enzymes to work in the stomach
How is a Low pH Helpful in the Stomach
- The low pH kills bacteria in food that we have ingested as it denatures the enzymes in their cells, meaning they cannot carry out any cell reactions to maintain life
- Pepsin, produced in the stomach, is an example of an enzyme which has a very low optimum pH – around pH 2
- The hydrochloric acid produced in the stomach ensures that conditions in the stomach remain within the optimum range for pepsin to work at its fastest rate
The Role of Bile
- It is alkaline to neutralise the hydrochloric acid which comes from the stomach
- The enzymes in the small intestine have a higher (more alkaline) optimum pH than those in the stomach
- It breaks down large drops of fat into smaller ones. This is known as emulsification. The larger surface area allows lipase to chemically break down the lipid into glycerol and fatty acids faster
Emulsification
- Emulsification is the equivalent of tearing a large piece of paper into smaller pieces of paper.
- This is an example of mechanical digestion, not chemical digestion – breaking something into smaller pieces does not break bonds or change the chemical structure of the molecules which make it up, which is the definition of chemical digestion.
Absorption of Food & Water
- Absorption is the movement of digested food molecules from the digestive system into the blood (glucose and amino acids) and lymph (fatty acids and glycerol)
- Water is absorbed in both the small intestine and the colon, but most absorption of water also happens in the small intestine
- Absorption takes place in the second section of the small intestine, the ileum
How is the Ileum Adapted for Absorption?
- The ileum is adapted for absorption as it is very long and has a highly folded surface with millions of villi (tiny, finger like projections)
- These adaptations massively increase the surface area of the ileum, allowing absorption to take place faster and more efficiently
Structure & Adaptations of a Villus
- Microvilli on the surface of the villus further increase surface area for faster absorption of nutrients
- Wall of villus is one cell thick meaning that there is only a short distance for absorption to happen by diffusion and active transport
- Well supplied with a network of blood capillaries that transport glucose and amino acids away from the small intestine in the blood
- Lacteal runs through the centre of the villus to transport fatty acids and glycerol away from the small intestine in the lymph
What is an ion Channel
They are proteins that span the cell membrane that allows charged molecules to pass through the membrane.
Difference between Alimentary Canal and Digestive System
Alimentary Canal - Involves the tubes that food pass through.
Digestive system - Includes the digestive glands
2 Places where Amylase is secreted
- Pancreas
- Salivary glands in the mouth
2 Places where Protease is secreted
- Stomach
- Pancreas
Where is lipase secreted?
The Pancreas
Two examples of Protease
Pepsin and Trypsin
Where is Trypsin is secreted?
The small intestine
Where is pepsin secreted
Stomach
Two parts where water is absorbed
The small intestine
The colon
