Human nutrition Flashcards
What makes a balanced diet
A balanced diet must include:
- Proteins for growth and repair
- Carbohydrates for energy
- Lipids for insulation and energy stores
- Vitamins and minerals in small quantities to maintain health
- Water for chemical reactions in cells
- Dietary fibres to bulk the intestines and push food through it to prevent constipation and bowel cancer
What is vitamin C useful for
Vitamin C is essential for forming part of collagen
It helps with skin and hair health, immunity, bone and gum health
Deficiency leads to scurvy
What is vitamin D useful for
Calcium absorption for bone and teeth health
Deficiency leads to rickets
What is scurvy
Vitamin C deficiency
Leads to anemia
What is rickets
Vitamin D deficiency
Leads to soft, weak bones
What is iron useful for
To make haemoglobin
What is calcium useful for
Needed for strong bone and teeth
What factors affect dietary needs
- Age
- Activity level
- Pregnancy
- Breastfeeding
What are the digestive enzymes
- Amylase. Breaks down maltose into glucose
- Protease. Breaks down proteins into amino acids
- Lipase. Breaks down lipids into fatty acids + glycerol
Where is amylase produced and found
Produced in salivary glands and pancreas
Pancreas secretes into duodenum
Where is protease produced and found
Found in stomach and small intestine
Produced in pancreas and secretes into small intestine
Where is lipase produced and found
Produced in pancreas, secreted in small intestine
What are the stages of digestion
- Ingestion. The taking of foods or drinks from mouth
- Mechanical digestion. The breakdown of food molecules into smaller pieces without them being chemically changed
- Chemical digestion. Breakdown of large, insoluble food molecules into small, soluble ones
- Absorption. The movement of small food molecules through wall of small intestine into blood
- Assimilation. The movement of food molecules into the cell where they are used
- Egestion. The passing of undigested or unabsorbed food in the form of faeces through the anus
Where is bile produced and stores
Produced in liver
Stored in gallbladder
What is the function of bile
- Neutralises stomach acid to provide optimum pH for enzymes in duodenum
- Emulsifies fats to provide larger surface area for lipases to break them down faster
Function of the mouth
- Mechanically digests food by chewing
- Salivary glands produce amylase to break down starch into maltose
Function of the Oesophagus
A tube connecting the mouth to the stomach
Function of the stomach
Mechanically digests food by churning
HCl kills bacteria and provides optimum pH for digestive enzymes
Function of the pancreas
Produces all digestive enzymes and secretes them in pancreatic juices
Function of the small intestine
Duodenum
- Finishes digestion of food molecules from stomach
Ileum
- Absorbs food molecules into blood
Function of the rectum
stores faeces
Function of the anus
Releases faeces
Function of the large intestine
Absorbs water from remaining material to make faeces
Function of the gallbladder
stores bile
Function of the liver
Produces bile
How is the small intestine adapted for absorption
- Very long
- Highly folded surface with millions of villi which increases surface area
- Surface of villus has microvilli further increasing surface area
- Walls of villus is 1-cell thick reducing distance of absorption
- Supplied with network of blood capillaries which increases concentration gradient
