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Biology IGCSE > Human nutrition > Flashcards

Human nutrition Flashcards

1
Q

Describe what is meant by a balanced diet

A

It’s a diet containing all essential nutrients we need in the right proportions.

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2
Q

State the principal dietary sources

A

Fats and oils
Carbohydrates
Minerals: calcium and iron
fibre
water
vitamin: C and D

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3
Q

describe the importance of carbohydrates

A

carbohydrates are an essential nutrient that provide the body with energy, support healthy digestion, and help with weight management. It is important to consume a balanced diet that includes both complex and simple carbohydrates to maintain optimal health.

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4
Q

Describe the importance of fats

A

fats are an essential nutrient- They are a source of energy since they are a highly concentrated source of energy and it can can store excess calories as fat
it protect the body’s organs by insulating and protecting them The layer of fat beneath the skin helps to maintain body temperature and protect against injury.
aids
in hormone production as they’re a main component
contribute to cell structure by being the main component of cell membranes
they also help the body absorb important nutrients like vitamins.
It’s important to consume a balanced diet that includes healthy fats in moderation to maintain optimal health.

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5
Q

Describe the importance of Vitamin C

A

Vitamin C is important for the function of the immune system, helping to protect against infections and disease. It promotes the production of white blood cells and antibodies, which are critical components of the immune system.
it’s essential for collagen production
Vitamin C is a powerful antioxidant, which means it helps to protect the body’s cells from damage caused by free radicals.
Vitamin C helps the body absorb iron from plant-based sources. This is important for people who follow a vegetarian or vegan diet, as plant-based sources of iron are not as readily absorbed by the body as animal-based sources.

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6
Q

Describe the importance of fibre

A

Iron is necessary for the production of ATP which is the primary energy source for cells
It plays a role in the production of white blood cells, which are critical components of the immune system.
Iron is important for cognitive function, including memory and concentration.
Iron is important for temperature regulation in the body. It helps to maintain body temperature by facilitating the transfer of heat from the core to the skin.
Iron is important for muscle function, including muscle contraction and relaxation.

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7
Q

Describe the importance of water

A

water is important for regulating body temperature, lubricating joints, supporting digestion, removing waste, and maintaining blood volume. It’s important to drink enough water to maintain proper hydration and support optimal health.

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8
Q

Describe the importance of vitamin D

A

Promoting calcium absorption: Vitamin D helps the body absorb calcium from the diet, which is important for maintaining strong bones and teeth.

Supporting immune function: Vitamin D plays a role in regulating the immune system, helping to protect the body against infections and disease.

Regulating cell growth and differentiation: Vitamin D is involved in the regulation of cell growth and differentiation, which is important for maintaining healthy tissues and organs.

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9
Q

Describe the importance of the mineral calcium

A

Building strong bones and teeth: Calcium is necessary for the formation and maintenance of strong bones and teeth. It provides the structural support that helps to prevent fractures and other bone-related injuries.

Supporting muscle and nerve function: Calcium is involved in the contraction and relaxation of muscles, and is important for the transmission of nerve impulses.

Regulating blood clotting: Calcium plays a role in the blood clotting process, which is important for preventing excessive bleeding after an injury.

Supporting heart health: Calcium is important for maintaining a healthy heart rhythm, and has been shown to help lower blood pressure.

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10
Q

Describe the importance of the mineral iron

A

Transporting oxygen: Iron is necessary for the production of hemoglobin, which carries oxygen from the lungs to the rest of the body.

Supporting energy production: Iron is involved in the production of adenosine triphosphate (ATP), which is the primary source of energy for the body’s cells.

Supporting immune function: Iron is involved in the production of white blood cells, which are important for fighting off infections and disease.

Supporting cognitive function: Iron is important for maintaining healthy brain function, and deficiency can lead to impaired cognitive performance.

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11
Q

State the causes of scurvy

A

A deficiency in vitamin C can lead to a number of health problems, including scurvy, a disease that causes bleeding gums, skin rashes, and fatigue. It can also lead to a weakened immune system and an increased risk of infections.

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12
Q

State the causes of rickets

A

Lack of exposure to sunlight: Vitamin D is produced in the skin when it is exposed to sunlight, so a lack of sunlight exposure can lead to vitamin D deficiency. This is especially common in regions with limited sunlight, or for individuals who cover their skin for cultural or religious reasons.

Inadequate dietary intake of vitamin D and/or calcium: A diet that is low in vitamin D and/or calcium can contribute to rickets, particularly in children who are still growing and developing.

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13
Q

Define ingestion

A

the taking of substances, e.g. food
and drink, into the body

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14
Q

Define diagestion

A

the breakdown of food

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15
Q

Define absorption

A

the movement of nutrients from
the intestines into the blood

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16
Q

Define assimilation

A

uptake and use of nutrients by
cells

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17
Q

Define egestion

A

the removal of undigested food
from the body as faeces

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18
Q

Describe physical digestion

A

the breakdown of
food into smaller pieces without chemical change
to the food molecules

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19
Q

What increases in physical digestion for the action of enzymes in chemical digestion?

A

physical digestion increases the
surface area of food for the action of enzymes in
chemical digestion

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20
Q

Describe the function of incisors

A

The sharp, chisel-like edges of incisors make them well-suited for cutting and slicing food into small, manageable pieces that can be more easily chewed and digested. Incisors are especially useful for cutting through tough and fibrous foods like meat, fruits, and vegetables.

Breaking down food: Once food has been cut into smaller pieces by incisors, it can be more efficiently broken down by other teeth and digestive enzymes in the stomach and small intestine.

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21
Q

Describe the importance of canines

A

Biting and tearing: Canine teeth are longer and sharper than incisors, making them well-suited for biting and tearing into tough foods like meat and fibrous fruits and vegetables.

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22
Q

Describe the importance of premolars

A

Grinding and crushing food: Molars are the primary teeth used for grinding and crushing food into small, manageable pieces that can be more easily swallowed and digested.

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23
Q

Describe the importance of molars

A

Grinding and crushing food: The primary function of molars is to grind and crush food into small, manageable pieces that can be more easily swallowed and digested. Their large, flat surfaces with multiple cusps are well-suited for breaking down tough and fibrous foods, such as meat, vegetables, and grains.

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24
Q

Describe the function of the stomach in physical
digestion

A

The stomach’s primary function is to break down large food particles into smaller pieces through mechanical action, which facilitates further digestion by enzymes in the small intestine.

The stomach accomplishes this through a process called churning, which involves contracting and relaxing the muscular walls of the stomach to mix and break down food. When food enters the stomach, the muscles of the stomach wall begin to contract and relax, grinding and mashing the food into a semi-solid mass called chyme. The churning action of the stomach helps to break down the physical structure of the food, reducing it to smaller pieces that can be more easily digested.

The stomach also has specialized cells that produce gastric juices, including hydrochloric acid and pepsin, which help to further break down food. The hydrochloric acid helps to reduce the pH of the stomach contents, creating an acidic environment that activates enzymes and helps to destroy harmful bacteria. Pepsin is an enzyme that breaks down proteins into smaller peptides and amino acids.

25
Q

Outline the role of bile

A

the role of bile in emulsifying fats and oils is to increase the surface area for chemical digestion, which allows for the efficient breakdown and absorption of fats in the small intestine.

26
Q

Describe chemical digestion

A

chemical digestion as the break down
of large insoluble molecules into small soluble
molecules

27
Q

State the role of chemical digestion

A

produces small soluble molecules that can be absorbed

28
Q

Describe the function of amylase

A

breaks down starch to simple reducing sugars

29
Q

Describe the function of protease

A

break down protein to amino acids

30
Q

Describe the function of lipase

A

breaks down fats and oils to fatty acids
and glycerol

31
Q

Describe the digestion of starch in the digestive
system:

A
  • amylase breaks down starch to maltose
  • maltase breaks down maltose to glucose on
    the membranes of the epithelium lining the
    small intestine
32
Q

State where, in the digestive system, amylase,
is secreted and where it acts

A

amylase is secreted in the mouth and the pancreas and acts in the mouth and the small intestine to break down carbohydrates into smaller molecules for absorption into the bloodstream.

33
Q

State where, in the digestive system, protease is secreted and where it acts

A

proteases are secreted by the stomach and the pancreas, and act in the stomach and the small intestine to break down proteins into smaller peptides and amino acids, which can be absorbed by the small intestine and transported to the liver for further processing and utilization by the body.

34
Q

State where, in the digestive system, lipase are secreted and where it acts

A

lipases are secreted in the mouth, stomach, and pancreas and act in the mouth, stomach, and small intestine to break down lipids into smaller fatty acids and monoglycerides. The fatty acids and monoglycerides are then absorbed by the small intestine and transported to the liver for further processing and utilization by the body.

35
Q

Describe the digestion of protein by proteases in
the digestive system:

A
  • pepsin breaks down protein in the acidic
    conditions of the stomach
  • trypsin breaks down protein in the alkaline
    conditions of the small intestine
36
Q

outline the role of bile

A

emulsifies fats and oils to increase the surface area for chemical digestion

37
Q

Describe the functions of hydrochloric acid
in gastric juice

A

Kills harmful microorganisms in food(by denaturing their enzymes) and provides an acidic pH for optimum enzyme activity.

38
Q

Where is the region in the digestive system whereas nutrients are absorbed

A

the stomach

39
Q

Explain the significance of villi and microvilli

A

Villi and microvilli are important anatomical features of the small intestine, which are responsible for the efficient absorption of nutrients from the digested food.

Villi are finger-like projections that extend into the lumen of the small intestine. They are covered with a layer of specialized epithelial cells, which form a thin barrier between the lumen of the small intestine and the bloodstream. The villi increase the surface area of the small intestine, allowing for more efficient absorption of nutrients. Additionally, the epithelial cells lining the villi have small finger-like projections on their surfaces called microvilli. The microvilli further increase the surface area of the epithelial cells, creating a brush border that enhances the absorption of nutrients.

The villi and microvilli play a significant role in the absorption of nutrients from the digested food. As the digested food enters the small intestine, it comes into contact with the villi, and the nutrients are absorbed by the specialized epithelial cells lining the villi. The nutrients are then transported across the epithelial cells and into the bloodstream, where they can be utilized by the body.

Overall, the villi and microvilli in the small intestine increase the surface area available for nutrient absorption, which allows for more efficient absorption of nutrients. This is essential for providing the body with the necessary nutrients for growth, maintenance, and repair of tissues and organs.

40
Q

Describe the structure of a villus

A

Villi are small, finger-like projections that extend from the lining of the small intestine. They are approximately 0.5 to 1 millimeter in length and are covered with a specialized type of epithelial cells.

Villi are finger-like projections that extend into the lumen of the small intestine. They are covered with a layer of specialized epithelial cells, which form a thin barrier between the lumen of the small intestine and the bloodstream. The villi increase the surface area of the small intestine, allowing for more efficient absorption of nutrients.

the structure of villi is optimized for efficient nutrient absorption. The finger-like projections increase the surface area available for nutrient absorption, and the specialized epithelial cells and blood vessels work together to transport the absorbed nutrients into the bloodstream.

41
Q

Describe the roles of capillaries in villi

A

the capillaries in the villi are critical for the efficient absorption of nutrients from the digested food. They provide a direct route for the transportation of nutrients into the bloodstream, and they help to maintain the pH balance of the small intestine.

42
Q

Describe the roles of lacteals in villi

A

the lacteals in the villi are essential for the absorption of dietary fats and fat-soluble vitamins. They provide a specialized transportation system that can handle the larger, more complex molecules that make up these nutrients.

43
Q

Where is most water absorbed?

A

small intestine but that some is also absorbed from the
colon

44
Q

Where is some of the water absorbed?

A

in the colon

45
Q

Describe the function of the stomach in physical
digestion

A

One of the primary functions of the stomach is to break down food into smaller particles through physical digestion. The stomach accomplishes this by using its muscular walls to churn and mix food with gastric juice, which is a mixture of digestive enzymes, hydrochloric acid, and mucus. The muscular contractions of the stomach are referred to as peristalsis and serve to physically break down the food into smaller pieces, which can be more efficiently digested and absorbed by the small intestine

46
Q

Describe chemical digestion

A

the break down of large insoluble molecules into small soluble molecules

47
Q

State the role of chemical digestion

A

produces small soluble molecules that can be absorbed

48
Q

function of amylase

A

amylase breaks down starch to simple
reducing sugars

49
Q

function of protase

A

proteases break down protein to amino acids

50
Q

function of lipase

A

lipase breaks down fats and oils to fatty acids
and glycerol

51
Q

Describe the digestion of starch in the digestive
system:

A

1- amylase breaks down starch to maltose
2- maltase breaks down maltose to glucose on
the membranes of the epithelium lining the
small intestine

52
Q

State where, in the digestive system, amylase,
protease and lipase are secreted and where they
act

A

Amylase is an enzyme that breaks down carbohydrates, specifically starches and sugars. It is secreted in the mouth by the salivary glands and in the pancreas. In the mouth, amylase begins the process of breaking down carbohydrates, while in the pancreas, it is released into the small intestine to continue carbohydrate digestion.

Protease is an enzyme that breaks down proteins into amino acids. It is secreted in the stomach by gastric glands and in the pancreas. In the stomach, protease is released in the form of pepsinogen, which is then activated by hydrochloric acid to become pepsin. In the pancreas, protease is released into the small intestine to continue protein digestion.

Lipase is an enzyme that breaks down fats into fatty acids and glycerol. It is secreted in the pancreas and released into the small intestine to digest fats.

53
Q

Describe the digestion of protein by proteases in
the digestive system:

A

(a) pepsin breaks down protein in the acidic
conditions of the stomach
(b) trypsin breaks down protein in the alkaline
conditions of the small intestine

54
Q

Explain what bile is

A

an alkaline mixture that
neutralises the acidic mixture of food and gastric
juices entering the duodenum from the stomach,
to provide a suitable pH for enzyme action

55
Q

function of smallnintestine

A

to absorb nutrients

56
Q

where is most water absorbed in? name the organ answell as another one where “some” is absorbed

A

most-> small intestine
some->colon

57
Q

describe the fuctions of Hydrochloric acid in gastric juice

A

to kill harmful microorganisms in the food and provide an acidic pH for opniul enzyme activity

58
Q

where is hydrochloric acid found?

A

gastic juice

Biology IGCSE (21 decks)

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