Chapter 7- Human Nutrition Flashcards Preview

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Flashcards in Chapter 7- Human Nutrition Deck (45):

What are examples of some essential nutrients?

Amino acids
Unsaturated fatty acids


Why are some nutrients essential and some non-essential

The nutrients that are non essential, another nutrient can be used for the same purpose or because they can be made in the body from another nutrient - essentials can't


Examples of no -essential nutrients?



What is an example of conditionally essential nutrients

Vitamin K is produced by the metabolism of symbiotic bacteria in the intestine- infants don't have colonies of this bacteria so at birth they are given supplementary injections


What is vitamin C what does it do

Is a compound called ascorbic acid- needed for the synthesis of the collagen fibres that form
Part of the tissue in the body- most plants and animals can synthesis vitamin c in the body


Why in some animals do it they not produce vitamin C?

Due to mutations that led to genes no longer producing the protein necessary to make vitamin C- due to mutation in the GLO gene which codes for the production of the enzyme l-guluno- lactone oxidase


Examples of mammals that cannot produce Vitamin C

Fish- Ray-finned-cod, salmon, herring


What can be the cause of a lack of vitamin C



Why are some amino acids essential in the body?

-of the 20 amino acids only half are that essential because they cannot be synthesized in sufficient quantities- other half can be made from nitrogen compounds


Example of essential amino acids in body

1) threonine and arginine are conditionally essential
Threonine can be synthesized if phenalanine is present
Arginine is produced by healthy living individuals


Example of essential fatty acids?

They cannot be synthesized in the body


Name 3 essential amino acids



What does a lack of essential amino acids affect?

The production of proteins


What is a lack of essential amino acids that affects the production of protein called?

Protein deficiency malnutrition


Why may essential amino acids by lacking?

Due to overall insufficiency of protein in the diet or to an imbalance in the types of protein


Consequences of protein deficiency malnutrition?

Causes a lack of blood plasma proteins which results in fluid being retained in tissues - causes swelling
Child development may be mentally and physically retarded with stunted growth and development disabilities
Adults may undergo serious weight loss


How much minerals are needed on the diet?

Relatively small quantities


What are minerals

Chemical elements


Example of mineral deficiency

Iodine- needed by thyroid gland to produced thyroxin - this stimulates the metabolic rate- lack of iodine squads IDD (iodine deficiency disorder)
- pregnant lady may be born with brain damage, mental development and intelligence are impaired


What are vitamins

Chemically diverse carbon compounds that cannot be synthesises by the body


What do vitamins do?

Serve a variety of roles such as co factors for enzymes, anti-oxidants and hormones


What is malnutrition caused by?

Is the outcome of a bad diet- could be a deficiency , imbalance or exceeds of nutrients in the diet


What is starvation ?

Is a consequence of a diet lacking in adequate protein and carbohydrates


Where is appetite controlled from?

Hypothalamus of the brain- appetite control centre


What hormones do the appetite control centre receive to reduce the desire to eat?

Small intestine secrets PYY3-36 when it contains food
Pancreas secreted insulin when blood glucose level is high
Adipose tissues secrets leptin when amounts of fat stored increases


What are the two main consequences of obesity?

Hypertension and type II diabetes


What is diabetes mellitus?

Sugar is present in the urine

Can be developed 2 Ways-
1) auto immune destruction of insulin secreting cells
2) decreased responsiveness of body cells to insulin due to 'burn out'


Type II diabetes have increased blood concentrations of fatty acids - linked to following risk factor ?

Diets rich in fat and low in fibre
Obesity due to overeating and lack of excercise
Genetic factors which affect fat metabolism


What are the symptoms of diabetes II

Elevated levels of blood glucose
Glucose in urine
Dehydration and thirst resulting from excretion of large volumes of urine


What are the results of diabetes if not treated?

Atherosclerosis (narrowing of arteries by fatty deposits)
Hypertension (raised blood pressure)
Coronary heart disease


What is there a correlation between with excessive weight gain.

And hypertension


What can lead to hypertension?

Weigh gain leads to higher cardiac output which can raise blood pressure
Abdominal obesity can increase vascular resistance which can raise blood pressure
Weigh gain is associated with arteries becoming stiffer and narrower

Can be caused from high salt intake


How does starvation lead to the breakdown of body tissue?

In absence of dietary intake of energy sources the body will first access glycogen stores- if no glucose it will break down its own muscle tissue to utilise the resulting amino acids as an energy storage - amino acids are sent to liver where they are converted to glucose- results in loss of muscle mass


Why does anorexia occur

Amounts of carbohydrates and fat consumed are too small to satisfy the body's energy requirements, so protein and other chemicals on body are broken down


What happens in anorexia

Skin becomes dry and bruises easily
Fine growth of hair tends to develop
Blood pressure is reduced


What happens when the body weight in a person with anorexia fall?

Skeletal muscle is digested
Heart muscle deteriorates


Evidence of scurvy not just being specific to humans

Holst and frolisch- produced papers by causing scurvy in Guinea pigs

Had been a lucky substituting Guinea pigs for pigeons as pigeons make there own vitamin c


Causes of phneylketonuria (PKU)

Is a genetic disease
Caused by mutation of a gene coding for enzyme that converts phenylaline into tyrosine
Mutation produces alleles of the gene that cannot catalase the conversion reaction

Symptoms of PKU only show in those who have the two recessive genes


Consequences of PKu

High phenylaline levels cause reduced growth of head and brain with mental retardation of young children and severe learning difficulties
Lack of skin and hair pigmentation


Why are PKU babies unaffected at birth?

Mothers metabolism has kept phyenylalanine and tyrosine levels normal- doctors can diagnose it there as the phyenylalanine levels rise- give supplements and different diet- fatal consequences can be avoided


What can lack of vitamin D cause?

Affect bone minerlizaration and rickets or oseomalacia


Why is vitamin D special?

Can be synthesized in the skin when sunlight or another source strikes the skin - if teenagers or adults spend enough time outside they don't need vitamin D in the diet

Children and elderly peeps told to eat vitamin D in diet - oily fishes, eggs and liver


What is there a correlation between in high levels of cholesterol and what?

High levels of cholesterol in blood plasma and an increased risk of coronary heart disease


3 reasons why advice given to minimise dietary heart diseases wil not certainly Lower the risk of coronary heart disease

1) reducing dietary cholesterol often has small effects on blood cholesterol levels so presumably has little effect on CHD rates
2) the liver can synthesis cholesterol so It is not the only source
3) genetic factors are more important than dietary intake and members of some families have high cholesterol levels even with low dietary intake


What can essential nutrients not be synthesized by?

The body- therefore have to be included in the diet

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