24. Human Nutrition Flashcards

1
Q

Nutrition def.

A

The way an organism obtains and uses its food

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2
Q

The two types of nutrition

A

Autotroph- makes own food through photosynthesis

Heterotroph- Eats other organisms for food

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3
Q

Digestion def.

A

The physical and chemical breakdown of food into soluble particles small enough to pass into the blood and to the body cells

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4
Q

Alimentary canal diagram

A
Mouth (salivary gland)
Oesophagus
Stomach
Duodenum (Liver, gal bladder, bile duct, pancreas)
ileum
Appendix
Caecum
Colon
Rectum
Anus
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5
Q

Steps in digestion (4)

A

Ingestion
Digestion
Absorption
Egestion

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6
Q

Ingestion def. and where

A

def. Food is taken into the alimentary canal

where: the mouth

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7
Q

Digestion def. and where

A

Def: The physical and chemical breakdown of food into soluble particles small enough to pass into the blood and to the body cells
Where: mouth, oesophagus, stomach, small intestine

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8
Q

Absorption def. and where

A

Def: the movement of digested food into the blood.
Where: small intestine

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9
Q

Egestion def and where

A

Def: Removal of undigested, unabsorbed food as faeces
Where: Anus

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10
Q

Def. of peristalsis

A

Rhythmic muscular contraction and relaxation in the wall of the alimentary canal (oesophagus) causing the food to move along the canal and be broken down

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11
Q

Where does mechanical digestion take place

A

teeth
peristalsis (oesophagus)
Contractions in stomach wall

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12
Q

Mechanical Digestion in mouth
Function
Name teeth and function

A

Food is broken down by the teeth by chewing
this increases the surface area for the enzymes to work.
Teeth: Incisors (front- biting of a piece), Canines (side-tear), Premolars and Molars (back- chew and grind)

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13
Q

Dental formula

A

32 teeth
I (2/2), C (1/1), P (2/2), M (3/3)
upper no.=teeth on top half of one side
lower no= teeth on bottom half of same side

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14
Q

Structure of a tooth

A
Diagram in copy
Crown, Root, Gums
Out---> In
Enamel (protect), 
Dentine (typical tooth structure), 
Pulp Cavity (contains blood vessels and provides nutrients for tooth)
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15
Q
Chemical digestion in the mouth
enzyme
role/substrate
product
production site
action site
optimum ph
A
Enzyme: amalyse
Role/Substrate: Digests starch
Product: Maltose
Production site: Salivary glands (mouth)
Action site: In the mouth
Optimum pH: pH 7/8
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16
Q

Digestion in the oesophagus

A

Made up of a muscular tube

Role: Brings food to stomach. Food moves by peristalsis so digests the food

17
Q

Digestion in the stomach
muscles that allow food to enter leave
shape
types of digestion

A

Food enters the stomach from the oesophagus when the cardiac sphincter muscle opens.
Is a J shaped muscular bag.
Involved in chemical and mechanical digestion
food leaves when pyloric muscle opens

18
Q

Mechanical digestion in the stomach

A

Muscles contract which churns the food and makes chyme

19
Q

Chemical Digestion

A

Produces gastric juice containing Mucus, HCL, Pepsinogen

20
Q

Role of

  1. Mucus
  2. HCL
  3. Pepsinogen
A
  1. Mucus: lines and protects the stomach so it doesnt digest itself.
  2. HCL: Hydrochloric acid: gives a pH of 1/2-the optimum pH for the enzyme. Kills bacteria present. Activates pepsinogen (pH 1/2). Denatures Amalyse (pH 7/8)
  3. Pepsinogen: enzyme produced in stomach. Inactivates to prevent self digestion. Converted to active enzyme pepsin by HCL when it comes in contact with food.
    Digests proteins to peptides
21
Q
Pepsin
Role
Substrate
Product
Production site
Action site
Optimum pH
A
Role: Digests protein
Substrate: Proteins
Product: Peptides
Production site: Stomach in gastric glands
Action site: Stomach
Optimum pH: pH 1/2
22
Q

How does the stomach prevent self digestion?

A

Mucus lines the wall. It is an alkaline (pH 7-14) so protects against acid pH.

  1. Cells in wall are tightly packed together and renewed at a rapid rate
  2. Pepsinogen is inactive until it comes in contact with food.
23
Q

Small intestine
Main Parts
pH
What happens

A

Main parts: Duodenum and ileum
pH 7/8 (because we left the stomach)
What happens: Chemical digestion (duodenum) Absorption (ileum)

24
Q

How the duodenum digests the food

A

wall of duodenum: secretes intestinal juices containing different enzymes which break down food.
Pancreas and liver: produce juices that travel to the duodenum.

25
Q

Role of pancreas

A

Produces pancreatic juices

they travel to the duodenum via the pancreatic duct. Contains enzymes lipase (fats) and amalyse (starch)

26
Q
Lipase
role
substrate
product
production site
action site
pH
A

role: breaks down fats
substrate: Fats/ Lipids
product: Fatty acids and glycerol
production site: Pancreas
action site: duodenum
pH: 7/8

27
Q
Amalyse
role
substrate
product
production site
action site
pH
A

role: digests starch
substrate: starch
product: maltose
production site: Pancreas/ small intestine
action site: small intestine
pH: 6.7/7

28
Q

Liver functions

A
Makes bile
Breakdown of toxic substances, 
Regulates heat, 
Break down amino acids to urea,
Breakdown carbohydrates to fat, 
Stores minerals (iron and copper), vit D and glycerol.
29
Q

Bile
consists of
functions
more functions

A

Consists of: Water, bile salts, bile pigment

Functions: emulsifies fats (fats easier to digest-in fat droplets) and neutralises acidic chyme

30
Q

Absorption
def.
where

A

def. The movement of digested food into the bloodstream.

Where: The ileum

31
Q

Villi
what
function

A

What: finger like folds in the lining of the small intestine.
Function: increases surface area for absorption of digested food.

32
Q

What is absorbed by villi and where they go

A

Water, Glucose, Amino acids, Vitamins, Minerals- absorbed into capillaries, travel to liver via the hepatic portal vein, stored by liver, released and passed to heart via hepatic vein and then passed to body.

Fatty acids and glycerol- absorbed into lacteal and transported to the lymph vessel and up to the subclavian veins into the vena cava to the heart.

33
Q

Structure of villus

A

Lacteal in centre which goes to lymph vessels.
Network of capillaries- goes to hepatic portal vein.
Villus on outside

34
Q

Function of hepatic vein and artery

A

Artery: Brings blood to the liver from the heart
Vein: Brings food from the liver to the heart

35
Q

How the villus are adapted for absorption:

A

Walls 1 cell thick
Long so increases surface area
Large capillary supply for efficient absorption
lacteal present for digested fat absorption

36
Q

Parts of the large intestine and functions

A
Appendix, Caecum: Function unknown 
Colon: 
Reabsorbs water, 
Forms solid waste (faeces), 
Bacteria in colon produce vit. B and K, 
Digest cellulose
Rectum: Stores faeces
Anus: Egestes faeces
37
Q

Benefits and importance of Fibre

Sources

A

Stimulates peristalsis in colon: prevent constipation
Provides bulk so prevents overeating as takes longer to digest
Provides and promotes gut bacteria
Regulates blood sugar levels
Lowers cholesterol
Sources: Wholegrain foods, Fruit and veg, Porridge