Digestive System Flashcards
(18 cards)
Three major categories of nutrients and broken down form:
- proteins _ amino acids
- fats _ fatty acids
- carbohydrates _ glucose
Stages of the digestive system and their functions:
Ingestion - The movement of food and liquids into the body via the mouth.
Digestion - breaking it down into molecules small enough to be absorbed
Absorption - The movement of small molecules from the stomach/intestines into the blood.
Egestion - Eliminating undigested waste products
How is ingestion done
- the lubrication of saliva released from the salivary glands
- swallowing of the food - which sends it onwards down the digestive tract
What is the epiglottis
A flap of skin that closes your windpipe when you swallow so food does not go into your lungs
What is peristalsis
Muscles of the oesophagus push the ball of food by contracting behind the ball. The muscles then relax.
What is mechanical digestion
- The physical breakdown of large ‘chunks’ of food into small pieces of food
- No new substances made
- Chewing breaks food into smaller pieces
- Stomach churns the food up into a fluid mixture
What is chemical digestion
- The chemical breakdown of small pieces of food into small molecules.
- Proteins and starches are broken into simpler units that can be readily absorbed
- New substances are made
- Most of the chemical digestive processes occur in thestomachand smallintestine
How is amylase used in chemical digestion
(AMYLASE IS A DIGESTIVE ENZYME)
- Salivary glands in your mouth make salivary amylase
- Breaks down starch when you chew your food, converting it into a smaller carbohydrate.
- Pancreas makes pancreatic amylase
- passes through a duct to reach your small intestine.
completes digestion of carbohydrates, producing glucose
Bile in digestion:
- Your liver produces a substance called bile
- Bile helps break down fats
- Bile is stored in the gall bladder and then released into the small intestine
Example of absorption
The small intestine is lined with minute finger-like processes villi that greatly increase its surface area and the rate at which absorption can take place.
Parts used in ingestion
- mouth
- tongue
Parts used in digestion
- mouth
- salivary glands
- stomach
- small intestine
- gallbladder
- pancreas
- liver
Parts used in absorption
- small intestine
- large intestine
Parts used in egestion
- rectum
- large intestine
- anus
Digestion of carnivores:
- Have only one stomach and sharp, strong teeth made for tearing into meat to get if off the bone.
- Short small intestines, small cecum
- Spend little time chewing their food, because their saliva lacks digestive enzymes to help them break down the food.
- The animal sends it directly down to the oesophagus where the digestive process begins. The food enters the stomach where it is digested and the nutrients extracted.
Digestion of herbivores:
- They spend a lot of time chewing their food with flat teeth made for grinding tough plants.
- Very long small intestines, large cecum
- The food reaches their stomachs where it is fermented to make for easier digestion.
- During the fermentation process, bacteria is excreted which helps to break down tough plant matter, making the nutrient extraction process easier.
Digestion of omnivores:
- The digestive system of an omnivore is more like that of a carnivore but they can more easily digest plant matter and process carbohydrates due to enzymes
- e.g. humans
What are amino acids
Amino acids are the building blocks of proteins and play an important role in body functions.
