Nutrition.txt

Nutrition is the way and organism obtains and uses its food

A type of nutrition where an organism makes its own food

A type of nutrition where an organism cannot make its own food

An organism that lives on a living organism ex. Flea

An organism that lives on a non living organism ex. Fungi

The physical and chemical breakdown of good into soluble particles small enough to pass into body cells

Food can be digested in a single location and individual cells to not have to contain a full range of digestive enzymes

1. Indigestion, food taken into alimentary canal

2. Digestion, food broken down into smaller pieces

3. Absorption, the movement of digested good from the alimentary canal into the blood stream

4. Egestion, removal of unabsorbed material as farces

Peristalsis is the rhythmic contraction and relaxation in the walls of the alimentary canal causing the food to move along the canal

Incisors - cutting

Canines - tearing

Premolars + molars - cutting grinding

• Water
• Salts
• Amylase
• Lysozyme

Food and gastric juice, made in stomach

• Pepsinogen
• HCl
• Mucus

Pepsinogen: Converts to pepsin by HCl. Digests protein to peptides

HCl: kills bacteria, activates pepsinogen

Mucus: lines and protects stomach wall

Mucus lines stomach, is alkaline and reduced acidity near stomach wall

Pepsin is released in inactive form. Does not come into contact with stomach rolls.

Cardiac sphincter muscle: closes entry from oesophagus to stomach

Pyloric sphincter muscle: contracts to close entry to duodenum from stomach


Importance: to prevent self digestion from stomach acids

Digestion and absorption

• Duodenum
• Jejunum
• Ileum

Most digestion

Absorb nutrients

1. Long tube, gives time for absorption

2. Villi, infoldings increase surface area for absorption of food

Lacteal and blood vessel

Lacteal: absorbs fatty acids and glycerol

Blood vessels: all other digested food glucose, amino acids, vitamins and minerals

• Colon
• Caecum
• Appendix
• Rectum
• Anus

• 1. Reabsorb water
• 2. Produce B group vitamins*
• 3. Digest cellulose*

• *Symbiotic bacteria
• Human benefit: B
• Bacteria benefit: nutrition

Bacteria that lies in close contact with another organism where at least one organism benefits

Function unknown

Stores faeces

Produces bile

Gall bladder

• Water
• Bile salts
• Bile pigments

Emulsifies fat: increases surface area of fat droplets

Neutralises: acidic chyme from stomach

Fibre stimulates peristalsis in the colon

• Prevents constipation
• Occurs when material passes through colon too slow, leads to too much water reabsorbed

• Amylase
• Pepsin
• Lipase

• R: digest starch
• P: salivary glands
• W: mouth
• pH: 8
• P: maltose

• R: digest protein
• P: gastric glands
• W: stomach
• pH: 2
• P: peptides

• R: digest fat
• P: pancreas
• W: duodenum
• pH: 8
• P: fatty acids+glucerol

Fatty acids and glycerol are absorbed from lacteal (small intestine) into the lymphatic system for transport to liver

Glucose, amino acids, vitamins and minerals pass into the blood capillaries

Hepatic portal vein brings these nutrients directly to liver

A vein that starts with a capillary becomes a vein and ends in a capillary

1. Hepatic portal vein connects the small intestine to the liver, transporting glucose, amino acids, minerals and vitamins

2. The hepatic vein transports nutrients and waste urea from liver to heart

3. From the heart nutrients are transported away through aorta to body cells dissolved in plasma

4. From the heart waste is transported away from the heart to the kidney through the aorta

• 1. Makes bile
• 2. Stores glycogen
• 3. Breaks down vitamins
• 4. Stores vitamins A, D, K (fat soluble)
• 5. Make plasma proteins
• 6. Makes urea from excess protein
• 7. Produces heat

• BGTVPUH
• Bile gets too violent please use heat

Taking in the correct amounts of all the essential nutrients in the diet

• Eat a variety of foods
• Eat each food type in moderatoon

AGE (young more than old)

GENDER (males more than females)

ACTIVITY (active more than inactive)

The daily food portion types an a average adult should eat

• Provides a medium for transport
• Provides a medium for reactions to occur