Nutrients and the Digestive System Flashcards
What are the five main groups of nutrients?
Carbohydrates, Proteins, Lipids, Vitamins, Minerals
Define Nutrients
Nutrients are substances found in food that are essential for our bodies to function.
Nutrients provide energy and materials for cell function, growth and repair.
What are carbohydrates
Carbohydrates are sugars, starches and fibre found in foods like fruit, vegetables, grains and dairy products.
Carbohydrates can be simple in structure called monosaccharides and disaccharides like glucose and sucrose.
What is the role of carbohydrates
Carbohydrates supply energy to cells for cellular respiration
What is protein.
They are building blocks essential for cell growth and repair in tissues like muscle, bone, hair and skin.
They are also important chemical like enzymes, hormones, and carriers like haemoglobin.
Proteins are made of smaller units call amino acids.
What are Lipids
Lipids are molecules also known as fats and oils
Lipids have important roles in cell membranes and some chemicals like hormones
They can also provide and store energy
Lipids are made up of two parts – glycerol and fatty acids
What are vitamins
Vitamins are organic nutrients that are required in only small amounts
They are essential for many processes in the cells
A lack of some vitamins can lead to vitamin-deficiency diseases like scurvy (vitamin C) and rickets (vitamin D).
Vitamins are found in a wide variety of foods like fruit, vegetables, eggs, dairy, fish and grains.
What are minerals
minerals are inorganic nutrients required in small amounts.
They also play an important role in many cell processes like nerve and muscle function and the immune system.
Minerals are essential for building structures like haemoglobin, bone and teeth.
What are the non-nutrients and what do they do?
Food contains additional important components that are not nutrients.
They are not used for energy, growth or repair but are essential for health.
These are water and fibre.
Describe water as a essential non-nutrient
Water makes up 2/3 of our body
It is essential for life
It makes up our cell cytoplasm and blood
It helps remove wastes from the body, keeps skin healthy, joints moving and regulates body temperature
Water is found in food like fruit, vegetables and dairy
Describe fibre as an essential non-nutrient
Fibre plays an important role in digestive function
Fibre is a carbohydrate (cellulose) that cannot be digested by humans
It helps material to move through the digestive system properly
If material moves through too slowly, too much water can be removed which causes constipation
This can cause damage to the digestive system
Fibre is found in food that comes from plants
What is digestion
In order to obtain nutrients from the food we eat, it needs to be broken down into small molecules so it can be absorbed and use by the cells of the body
What are the two types of digestion
Mechanical and Chemical
What is mechanical digestion
Mechanical digestion breaks food down physically (large pieces into small pieces)
Mechanical digestion includes chewing which occurs in the mouth and churning which occurs in the stomach
What is chemical digestion
Chemical digestion breaks down food using enzymes and breaks food into its building blocks e.g. proteins are broken into amino acids so they can pass into the bloodstream
What is digestive enzymes
Digestive enzymes are essential to complete the process of breaking down food into small particles
What are the three digestive enzymes
Amylases, proteases, and lipases
What is the role of amylases
Digest carbohydrates
Found in the mouth & small intestine
What is the role of proteases
Digest proteins
Found in the stomach & small intestine
What is the role of lipases
Digest lipids
Found in small intestine
What is the order of digestion
Food > Mouth, Oesophagus > Large intestine > Small intestine > Stomach
Describe the mouth
In the mouth food is chewed by the teeth with the help of the tongue.
Saliva adds moisture to make it easy to swallow.
Saliva also contains amylase which begins to breakdown carbohydrates.
The chewed up food is called a bolus.
Describe the oesophagus
When food reaches the back of the tongue, we swallow.
This pushes the food bolus down the oesophagus to the stomach.
The movement of the oesophagus is called peristalsis and is waves of muscular contraction.
Describe the stomach
The stomach is very acidic as it also produces hydrochloric acid which activates the protease and destroys foreign material.
Describe the small intestine
The small intestine is where the nutrients from food will pass into the blood stream.
The small intestine has special structures called villi to maximise absorption of nutrients.
What is the bolus
a small, rounded mass of a substance, especially of chewed food at the moment of swallowing:
Describe the liver
The liver has many roles important to the body.
For digestion, it produces bile which assists the mechanical digestion of lipids.
It breaks up large globules of fat into small ones in a process called emulsification.
Bile is stored in the gall bladder before being released into the small intestine.
Describe the pancreas
The pancreas makes all three types of digestive enzymes – amylases, proteases and lipases.
These are added into the small intestine to complete chemical digestion of carbohydrates, proteins and lipids.
Describe the large intestine
When the majority of nutrients have been absorbed from the material in the small intestine, the remaining material passes into the large intestine.
Water is absorbed from the undigested material and turns into a more solid form called faeces.
This can be stored in the rectum before passing out of the body through the anus.
