Human Nutrition

What are glands that aid digestion?

Liver

Pancreas

Salivary gland

What are the components of small intestine?

Duodenum

Ileum

What are the components of large intestine?

Rectum

Anus

Colon

Appendix

Caecum

What are 2 types of nutrition?

Autotrophic

Heterotrophic

Where does alimentary canal start and end?

Starts at the mouth, ends at the anus

What are the steps in human digestion?

Ingestion: food enters mouth

Digestion: breakdown of food

Absorption: food absorbed into the blood by diffusion

Egestion: removal of unwanted food waste

What is digestion?

Breakdown of food into smaller particles

Why is digestion necessary?

Make food more soluble

Allow food to be absorbed into bloodstream

What are the 2 types of digestion?

Mechanical

Chemical

What are the locations of mechanical digestion?

Mouth

Oesophagus

Stomach

Duodenum

What are the locations of chemical digestion?

Mouth

Stomach

Duodenum

What are the 4 types of teeth?

Incisors

Canines

Premolars

Molars

What is the function of incisors?

Cut, slice and bite

What is the function of canines?

Tear & grip food

What is the function of premolars?

Crush & chew food

What is the function of molars?

Crush & chew food

What is the dental formula?

2(I2/2 C1/1 P2/2 M3/3) = 32 teeth

How does chemical digestion occur in the mouth?

Amylase breaks down the of food in the mouth

Saliva softens & dissolves food

What is the pH of amylase?

7

What are the functions of the oesophagus?

Carries food from mouth to stomach where it is digested mechanically

Food is moved along alimentary canal by peristalsis

Peristalsis helps break down food mechanically

What is the role of fibre?

Helps us absorb water from large intestine

Helps stimulate peristalsis

Cell walls contain cellulose which provides us with fibre

Name 2 parts of the alimentary canal where peristalsis occurs that helps with mechanical digestion:

Oesophagus

Small intestine

What is the stomach?

Muscular bag that stores food and digests food

How does the stomach carryout mechanical digestion?

Churns food, creating a mixture known as chyme

How does the stomach prevent self-digestion?

Mucous lines the stomach and is alkaline which reduces acidity (neutralises) near the stomach wall

Pepsin is released as inactive pepsinogen (so it doesn’t damage the stomach wall)

What is the role of hydrochloric acid in the stomach?

Kills harmful bacteria

What is the substrate that pepsin reacts with & the product it forms?

Protein

Peptides

What are the glands associated with small intestine that aids digestion?

Liver

Pancreas

What is the function of the pancreas in relation to digestion?

Secretes sodium bicarbonate thorough the pancreatic duct

Sodium bicarbonate neutralises the chyme from stomach in duodenum

Amylase and lipase secreted in duodenum to help digestion

What is the digestive role of the liver?

Produces bile

Functions of the liver other than bile

Breaks down excess amino acids to form urea

Converts excess carbohydrates to fats

Converts glucose to glycogen for storage

Breaks down red blood cells

Where is bile made & stored?

Made in liver

Stored in gall bladder

What duct releases bile into duodenum?

Bile duct

What are the functions of bile?

Emulsifies fats in duodenum

Contains sodium bicarbonate which helps neutralize chyme from stomach

What are the features of the duodenum?

25cm long

Carries out digestion

What are the features of the ileum?

5.5 meters long

Carries out absorption of food by diffusion

What are the adaptations of villi?

Rich supply of blood to carry away products

One cell thick

Villi increase surface area for absorption

Each villi has a lacteal to absorb and carry away fats

What substances does the ileum absorbs into the blood

Glucose, amino acids & vitamins

What is the feature of the villi that is responsible for absorbing fats?

Lacteal

Name the blood vessel that supplies oxygenated blood to the liver

Hepatic artery

Name the blood vessel that removes urea and deoxygenated blood away from the liver

Hepatic vein

Name the blood vessel that the hepatic artery arises from

Aorta

To which organ does digested nutrients get first transported to?

Liver

Name a vein that carries blood between the intestine and liver

Hepatic portal vein

Name a vein has begins and ends with capillaries

Hepatic portal vein

Name a vein that carries blood rich in urea out of the liver

Hepatic vein

What is deamination?

The process in which excess amino acids are broken down in the liver to form urea

What are the functions of the large intestine?

Colon is used to reabsorb water

Egestion

What is symbiosis?

Two organisms live in close association with each other and there’s at least one benefit

What is symbiotic bacteria?

Bacteria that live on another organism and involves benefit for both organisms

What are the benefits of symbiotic bacteria?

Feeds on waste products to produce vitamin B and K

Breaks down food which is absorbed into body

What is a balanced diet?

Eating the right amount of each food for better health