digestion Flashcards
What are the structures that food passes through in the human alimentary canal in order?
Mouth, Oesophagus, Stomach, Small Intestine (Duodenum and Ileum), Large intestine (Colon and Rectum), Anus
The liver, gall bladder, pancreas, and bile duct are essential for digestion but food does not pass through them.
What are the functions of the mouth/salivary glands?
Mechanical digestion by teeth, Amylase in saliva begins starch breakdown
What are the functions of the oesophagus?
Connects mouth to stomach, Moves food by wave-like contractions
What are the functions of the stomach?
Mechanically digests food by churning, Protease enzymes like pepsin begin to work, Hydrochloric acid kills bacteria and provides optimum pH for pepsin
What are the functions of the small intestine?
Food is digested by pancreatic enzymes in the duodenum, Absorption of food and water in the ileum
What are the functions of the large intestine?
Absorbs water from undigested material to produce faeces in the colon, Stores faeces in the rectum for release through the anus
What are the functions of the pancreas?
Releases amylase, protease, and lipase into the duodenum
What is the purpose of peristalsis?
To move food along the alimentary canal without help of gravity
Where does peristalsis happen?
Oesophagus, Stomach, Small intestine, Large intestine
In the stomach and small intestine, peristalsis also mechanically breaks down the bolus into chyme.
How does peristalsis work?
Circular and longitudinal muscles contract rhythmically in a wave-like action
What are the roles of digestive enzymes?
Speed up and lower activation energy of chemical reactions for food breakdown
What are the three enzymes produced in the pancreas?
Lipase, Protease, Amylase
What does amylase break down into what and where is it produced?
Breaks down starch into maltose, produced in salivary glands, pancreas, and small intestine
What does maltase break down into what and where is it produced?
Breaks down maltose into glucose, produced in the small intestine
What do all proteases break down into what?
Proteins into amino acids
What is the protease enzyme produced in the stomach called and what does it break down into what?
Pepsin, breaks down proteins into amino acids
What do the protease enzymes produced in the pancreas and small intestine break down?
Proteins into amino acids
What does lipase break down into what and where is it produced?
Breaks down lipids into glycerol and fatty acids, produced in the pancreas only
Where is bile produced?
The liver
Where is bile stored before release to the small intestine through the bile duct?
The gall bladder
What are the functions of bile?
Neutralises stomach acid, Mechanical breakdown of lipids into smaller droplets (emulsification)
How is the small intestine adapted for absorption?
High surface area due to length and villi, Peristalsis mixes food and enzymes, Enzymes turn food into smaller absorbable molecules
How is the villus adapted for absorption?
Many microvilli, Very thin wall, Network of blood capillaries, Lacteal for fatty acids and glycerol, Enzymes produced in villus walls
What are all the components you must have in the right proportions for a balanced diet?
Carbohydrates, Proteins, Lipids, Minerals, Vitamins, Water, Dietary Fibre
These components are essential for maintaining health and supporting bodily functions.
What are the functions of carbohydrates for humans?
They are a source of energy
Carbohydrates are the body’s primary energy source.
What are the functions of lipids for humans?
Energy storage, Necessary for cell membranes, Insulation
Lipids play critical roles in energy storage and cell structure.
What are the functions of proteins for humans?
Growth and repair, Enzymes, DNA and hormones
Proteins are vital for various biological processes.
What are the functions of dietary fibre for humans?
Provides indigestible bulk for the intestine to push food through, preventing constipation
Dietary fibre aids in digestive health.
What are the functions of water for humans?
Needed for chemical reactions, Temperature regulation, Maintaining blood water levels
Water is crucial for all physiological processes.
What are sources of carbohydrates for humans?
Bread, Pasta, Rice, Potatoes
These foods are staple sources of carbohydrates.
What are sources of proteins for humans?
Meat, Fish, Eggs, Nuts, Beans
These sources provide essential amino acids.
What are sources of lipids for humans?
Butter, Oil, Nuts
These foods contain healthy fats.
What are sources of dietary fibre for humans?
Vegetables, Wholegrains
These foods contribute to daily fibre intake.
What are sources of water for humans?
Water, Milk, Juice, Fruits & Vegetables
These sources help meet hydration needs.
What are the functions of calcium for humans?
Needed for strong bones and teeth, Deficiency can cause rickets
Calcium is essential for skeletal health.
What are the functions of iron for humans?
Needed for production of haemoglobin, Deficiency can cause anemia
Iron is crucial for oxygen transport in the blood.
What are the functions of vitamin A for humans?
Needed for night vision
Vitamin A is a component of the pigment in the retina.
What are the functions of vitamin D for humans?
Helps absorb calcium, Needed for strong bones and teeth, Deficiency can cause rickets
Vitamin D is vital for calcium metabolism.
What are the functions of vitamin C for humans?
Needed for collagen production, Necessary for immune system
Vitamin C supports skin and connective tissue health.
What are the sources of calcium for humans?
Milk, Cheese, Eggs
These foods are rich in calcium.
What are the sources of iron for humans?
Red meat, Liver, Leafy green vegetables
These foods provide heme and non-heme iron.
What are the sources of vitamin A for humans?
Leafy green vegetables, Eggs, Carrots
These foods contain beta-carotene and retinol.
What are the sources of vitamin C for humans?
Citrus fruits, Green vegetables, Strawberries
These foods are high in ascorbic acid.
What are the sources of vitamin D for humans?
Sunlight, Eggs, Fish
Vitamin D can be synthesized from sunlight exposure.
How does age affect energy and nutritional requirements?
Energy requirement increases until adolescence, Decreases with age
Nutritional needs change throughout the life cycle.
How do activity levels affect energy and nutritional requirements?
More active individuals need more energy and protein
Activity level directly influences caloric and protein needs.
How does pregnancy affect energy and nutritional requirements?
Increased energy, calcium, iron, and protein are needed
Nutritional demands rise significantly during pregnancy.
How does breastfeeding affect energy and nutritional requirements?
More energy and calcium are needed for breast milk production
Nutritional needs remain elevated during lactation.
How does a person’s sex affect their energy requirements?
Males typically need more energy than females
Differences in body composition influence energy needs.
Outline an experiment to test for the energy content of a food sample.
Record starting temperature of water, Weigh food sample, Burn food, Record final temperature
This method measures the energy transferred to the water.
How do you work out the amount of energy in a food sample per gram?
Energy transferred = 4.2 x Temp. Increase x Mass of water / Mass of food sample
This formula calculates energy density.
Why might the result you get for the energy of the food sample be less than it really is?
Heat loss to surroundings, Incomplete burning of food
Several factors can lead to inaccurate energy measurements.
