SAFOLO — 2e.2 — Nutrition in humans

Question 1

Balanced diet?

Answer 1

A diet in which all components needed to maintain health are present in appropriate proportions

Question 2

Why do humans need a balanced diet?

Answer 2

To ensure the body is provided with components to maintain good health

Question 3

What does a balanced diet contain?

Answer 3

• Carbohydrates (starch, glucose)
• Protein
• Vitamins
• Lipids (fat & oil)
• Dietary fibre
• Minerals
• Water

Question 4

Function of carbohydrates?

Answer 4

Direct energy source
Deficiency: Lack of energy
Source: Meat, starch

Car(bohydrates) give out energy with meat

Question 5

Function of protein?

Answer 5

Growth and repair
Deficiency: Marasmus - poor growth
Source: Meat

Pro-teens frow and repaire while Marasmus - who doesn’t grow - eats meat

Question 6

Function of Vitamin A?

Answer 6

Healthy eyesight
Deficiency: Night blindness
Source: Carrots

A carrot A day keeps night blindness Away

Question 7

Function of Vitamin C?

Answer 7

Heal wounds and rebuilds tissue
Deficiency: Scurvy - bleeding gums
Source: Lemon

(vitamin) SEA captain Wounds and Tissue screams BLEEDING SCURVY LEMONS

Question 8

Function of Vitamin D?

Answer 8

Strengthen teeth and bones
Deficiency: Rickets - curved bones
Source: Margarine

Dentists Rick(et)roll with Margarine

Question 9

Function of Lipids?

Answer 9

Insulation and Energy storage
Deficiency: Weak immunity, hair loss
Source: Meat, oil

Lips(ids) insulate the energy storage until our hair falls out and we have weak immunity with meat and oil

Question 10

Function of dietary fibres?

Answer 10

Lowers Cholesterol
Deficiency: Constipation
Source: Vegetables

Fi(bres)ve low cholesterols had constipation with vegetables

Question 11

Function of calcium?

Answer 11

Strengthen teeth and bones
Deficiency: Rickets - curved bones
Source: Milk

Cal(cium) has strong teeth and bones because his friend Rick(ets) told him to drink milk

Question 12

Function of iron?

Answer 12

Promote Haemoglobin
Deficiency: Anaemia - poor Oxygen transport
Source: Meat

Iron (hea)Man(globin) and his girlfriend Anaemia (poor oxygen transport) eat meat

Question 13

Function of water?

Answer 13

Allows chemical reactions to occur
Deficiency: Dehydration, kidney failure
Source: Water

Question 14

Factors that affect energy requirements?

Answer 14

• Age
• Activity levels
• Pregnancy

Question 15

How does age affect energy requirements?

Answer 15

• Amount of energy required increases towards adulthood for growth and muscle development

Question 16

How do activity levels affect energy requirements?

Answer 16

• Amount of energy required increases with activity level as more energy is needed to allow muscle contractions to facilitate exercise via respiration

Question 17

How does pregnancy affect energy requirements?

Answer 17

• Amount of energy required by females during pregnancy increases since more energy is needed to support growth of developing fetus, and the large mass that the Mother will cary

Question 18

Mouth?

Answer 18

• Mechanical digestion occurs
• large food is turned into a bolus to provide large SA:V ratio for amylase to break down starch in food into glucose
• Saliva lubricates bolus for easy swallow

Question 19

Oesophagus?

Answer 19

• Tube connecting mouth to stomach
• Peristalsis (wave-like contractions) occur to push bolus down the tube towards the stomach

Question 20

Stomach?

Answer 20

• Peristalsis continues mechanical digestion, and enzymes begin chemical digestion
• Hydrochloric acid maintains optimum pH to increase rate of enzyme activity and metabolic reactions

Question 21

Small intestine?

Answer 21

• Lined with Villi to absorb digested soluble molecules into blood
• duodenum is the first part, helps further digest food coming from stomach and absorbs nutrients to be used by the body
• ileum is the last part, connects to cecum and helps further digest food

Question 22

Large intestine?

Answer 22

• Absorbs water from undigested food to produce faeces (stored in rectum and removed through anus)
• colon removes water and nutrients
• rectum is at end of large intestine where faeces are held before moving to anus

Question 23

Pancreas

Answer 23

• Synthesises pancreatic enzymes (Amylase, protease and lipase)
• Secretes pancreatic enzymes into the stomach and small intestine for digestion

Question 24

Peristalsis?

Answer 24

Wave-like muscle contractions that push food bolus down the Oesophagus from the mouth to anus. Occurs in the stomach and gut

Question 25

How does peristalsis occur?

Answer 25

• Circular muscles change radius of oesophagus, longitudinal muscle change length of oesophagus
• Contraction of circular muscles behind food constricts gut to prevent bolus from being pushed back to mouth
• contraction of longitudinal muscle where food bolus is located moves it along gut (intestines)
• as a result, wave-like muscle contractions occur which push food down

Question 26

What are the digestive enzymes?

Answer 26

Amylase/maltase, Protease, Lipase
Amylase breaks down starch (big molecule) to glucose
Protease breaks down protein to amino acids
Lipase breaks down lipids to fatty acids and glycerol

Question 27

Bile?

Answer 27

Alkaline substance produced in the liver and stored in the gall bladder.
Emulsifies lipid molecules into droplets with larger SA:V ratio to increase the rate of digestion

Question 28

How does bile neutralise small intestine acid?

Answer 28

• Enzymes in small intestine function optimally in alkaline conditions (optimum pH of 8-14)
• However churning food in stomach by HCL acid creates acidic environment
• Bile will neutralise HCl to maintain Alkaline conditions, allowing optimum enzyme activity and increasing the rate of metabolic reactions

Question 29

How does bile emulsify lipids?

Answer 29

• As the breakdown and digestion of lipid molecules requires a long period of time, bile is used to emulsify large lipid molecules into small droplets
• lipid droplets will have larger SA:V ratio, allowing faster breakdown by lipase in fatty acids and glycerol, hence increasing rate of lipid digestion

Question 30

Villus?

Answer 30

Small finger-like projections lining the intestine wall that absorb digested soluble food molecules

Question 31

How are villi adapted for absorption?

Answer 31

• Thin cell wall
• Large SA:V ratio
• Dense capillary network
• Lacteal

Question 32

How does a thin cell help villus?

Answer 32

Thin cell wall (one cell thick) to minimise distance of diffusion of digested soluble molecules, increasing rate of absorption

Question 33

How does a large SA:V ratio help villus?

Answer 33

Folded to increase SA:V ratio for diffusion of digested soluble molecules, increasing rate of absorption

Question 34

How does a dense capillary network help villus?

Answer 34

Dense capillary networks nearby to provide rich blood supply, creating strong concentration gradient for the diffusion of digested soluble molecules, increasing rate of absorption

Question 35

How does a lacteal help villus?

Answer 35

Absorb and transport fatty acids and glycerol from intestine to lymphatic system

Question 36

How is the small intestine adapted for absorption

Answer 36

• Very long
• Have villi and microvilli to increase surface area
  muscular contractions to move food
• Digestive enzymes