7: Human Nutrition Flashcards
What are lipids made of?
Fatty acids and glycerol
What are proteins made of?
amino acids
What are carbohydrates?
They can be simple sugar molecules such as glucose or larger, more complex molecules such as starch, glycogen or cellulose. These complex carbohydrates are made of many individual glucose molecules joined together into chains
What do organisms use nutrients for?
1: Growth
2: As a source of energy
3: For repair or respiration
What is a balanced diet?
A balanced diet includes all essential nutrients in the correct amounts needed by an organism for energy, growth, repair & replacement and to remain healthy
State the principal dietary sources and describe the importance of carbohydrates
Principal dietary sources: rice, pasta, bread, potatoes, cereal products
Importance of carbohydrates: Energy source and storage
Fibres: prevent constipation and concentration of cholesterol
Starch: store excess energy
Sugars: produce energy
State the principal dietary sources and describe the importance of fats and oils
Principal dietary sources: butter, cheese, fats in meats & fish, nuts
Importance of fats and oils: store energy, insulation, make membranes, buoyancy
State the principal dietary sources and describe the importance of proteins
Principle sources of protein: meat, fish, beans, eggs, milk, nuts, potatoes
Importance: bodybuilding, making new body tissues, repairing worn/damaged tissues, energy
State the principal dietary sources and describe the importance of vitamins C and D
Principal dietary sources: (vitamin c) grapefruit, oranges, melon, lemons, tomatoes, potatoes, strawberries (vitamin d) eggs, liver, white fish, sardines, milk
Importance: prevents scurvy (vitamin c) and rickets (vitamin d)
State the principal dietary sources and describe the importance of mineral ions (calcium and iron)
principal dietary sources: (calcium) milk, cheese, bread, flour products (iron) meat, green vegetables and potatoes
importance: prevent rickets (calcium) and prevent anaemia (iron)
State the principal dietary sources and describe the importance of fibre (roughage)
principal dietary sources: vegetables etc
importance: gives diet bulk and helps digestive system to work properly and prevents constipation
State the principal dietary sources and describe the importance of water
principal dietary sources: water
importance: stay hydrated
What causes scurvy and rickets?
Scurvy: lack of vitamin C
Rickets: lack of vitamin D
What is the liver?
A large, important gland that makes bile to emulsify fats so they can mix with the digestive juices in the small intestine
What is the gall bladder?
stores bile made by the liver
What is the duodenum?
first part of the small intestine. bile and juice from the pancreas are added to the food in the duodenum
what is the function large intestine/colon?
absorbs water from the chyme (the pulpy acidic fluid which passes from the stomach to the small intestine, consisting of gastric juices and partly digested food) into the blood, leaving the solid waste called faeces. Minerals are also absorbed.
what is the caecum?
first part of the large intestine
what is the appendix?
plays no part in digestion and is of little value in humans (attached to the end of the caecum)
what is the rectum?
last part of the large intestine
what is the oesophagus/gullet
tube from mouth to stomach
what is the stomach?
> acts as a reservoir for food while it is churned and mixed with the gastric juice.
the juice contains hydrochloric acid to kill germs, pepsin, an enzyme to digest protein, and rennin, an enzyme to clot milk, making it easier to digest
the acid chyme formed is eventually squirted into the duodenum
What are the 4 types of sphincter?
1: Cardiac sphincter
2: Pyloric sphincter
3: ileocaecal sphincter
4: anal sphincter
what is the pancreas?
a gland which makes pancreatic juice. This juice is alkaline to neutralise the stomach acid. it contains proteases, lipases and amylases. pancreatic juices are emptied into the duodenum
what is the small intestine? (or ileum)
a tube about 6m long. it makes enzymes to complete the digestive process. the soluble nutrients formed are mostly absorbed through its walls into the blood, leaving little of value to enter the colon.
define ingestion
the taking of substances, e.g. food and drink, into the body through the mouth
define digestion
the breakdown of food
define absorption
uptake and use of nutrients by cells
define assimilation
the movement of nutrients from the intestine into the blood
define egestion
the removal of undigested food from the body as faeces
give the regions of the alimentary canal involved and the associated organs involved with the process of ingestion
regions: mouth and oesophagus
associated organs: salivary glands
give the regions of the alimentary canal involved and the associated organs involved with the process of digestion
regions: stomach, ileum, small intestine, duodenum
associated organs: liver, pancreas, gall bladder, salivary glands
give the regions of the alimentary canal involved and the associated organs involved with the process of absorption
regions: colon, large intestine, small intestine, ileum, duodenum
associated organs: body cells
give the regions of the alimentary canal involved and the associated organs involved with the process of assimilation
region: small intestine, duodenum, ileum
associated organs: body cells
give the regions of the alimentary canal involved with the process of egestion
rectum and anus
define physical digestion
the breakdown of food into smaller pieces without chemical change to the food molecules
why does physical digestion occur?
in order to increase the surface area of food for the action of enzymes in the chemical digestion
name the 4 different types of teeth
incisors, canine, premolars and molars
what is the incisor used for
cutting food (chisel shaped teeth)
what is the canine used for
gripping and tearing food (sharp)
what are the premolars and molars used for
grinding and crushing food (flat topped, have points/cusps)
what is the small flap of cartilage that closes over the opening to the trachea/glottis called and why is it important?
epiglottis, to prevent food from going to your lungs
what is the function of the enamel?
protects the tooth from physical, chemical and thermal forces
what is the function of the dentine?
reinforces the tooth’s enamel
what is the function of the pulp cavity?
contains pulp which carries nerves to give the tooth feeling and blood vessels to feed the tooth
what is the function of the nerves in the tooth?
sense hot and cold
what is the function of the blood vessels in your teeth?
provide teeth with nutrients
what is the function of the cement?
fixes tooth to jaw
what is the function of the gum?
keeps tooth in place
what is peristalsis
rhythmic squeezing and relaxing by the muscles to help mix up food with juices and bring it up against the walls so that it can be absorbed by the blood
describe physical digestion by bile
the main function of bile is to emulsify fats and increase the surface are so that the enzymes can work more efficiently
define chemical digestion
the breakdown of large, insoluble molecules into smaller, soluble molecules. Its role is to produce molecules that can be absorbed
why does starch digestion stop in the stomach?
the optimum pH for amylase is 7.0, so the highly acidic conditions in the stomach would denature them.
describe the function of protease
breaks down protein to amino acids
describe the function of amylase
breaks down starch to simple reducing sugars
describe the function of lipase
breaks down fats and oils into fatty acids and glycogen
what is absorption?
the movement of nutrients from the intestines into the blood
list the adaptations to help the small intestine absorb food.
> long tube, has ridged walls covered with finger-like projections called villi and these are covered in cells with projections called microvilli. this gives a very large surface area for exchange
rich blood supply - large surface area for exchange
has lacteals which help with the absorption of less soluble materials
