Chapter 9 - The Digestive System - REVISION Flashcards
What is digestion?
Digestion is the breakdown of food into components which can be used within the body.
What two ways does digestion occur in?
Digestion occurs in two ways: mechanical and chemical.
What is mechanical digestion?
Mechanical digestion is the physical breakdown of food into smaller pieces.
What is chemical digestion?
Chemical digestion is the chemical breakdown of food by substances known as enzymes.
What part of the body does chemical and mechanical digestion first occur?
The mouth.
What is the first stage of the digestive process?
Ingestion
What is ingestion
Ingestion is the intake of food into the mouth where it is chewed and swallowed.
Where does the initial stages of digestion take place? with the aid of what?
The mouth, with the aid of the teeth, tongue and salivary glands.
What stage of the digestive process does mechanical and chemical digestion take place first?
Ingestion.
Where does mechanical digestion begin?
Mechanical digestion begins with the teeth.
What are teeth used for in the first stages of what?
Teeth are used in the first stages of digestion to break up food into smaller pieces by tearing, crushing and grinding it.
What are the four types of tooth?
Incisor, Canine, Premolar and Molar.
What is related to the diet of the animal?
The number and type of teeth present in an animal’s mouth is related to the diet of the animal.
Define Incisors
Chisel-like teeth used for cutting and biting.
Define Canines
Pointed and sharp teeth used for tearing food.
Define Premolar
Relatively flat teeth used for grinding.
Define Molar
Flat teeth used for crushing food.
Be able to draw the LS of a tooth (pg 109)
Read
What do Herbivores eat?
Herbivores eat plant materials only.
What do herbivores use their molars and premolars for?
Crushing and grinding material such as grass.
Name 3 Herbivores
Cattle, Sheep and Horses.
What do Carnivores eat?
Carnivores eat meat.
What do carnivores use for tearing what?
Carnivores use their canine teeth for tearing flesh.
What do Omnivores eat? Give an example of an omnivore.
Omnivores eat both plant material and meat. Pigs are an example of an omnivore.
_____ do not have a specialised _____ but use all the types of _____ listed to aid _____ of a variety of foods.
Omnivores do not have a specialised dentition but use all the types of teeth listed to aid digestion of a variety of foods.
What is the dental formula of a pig?
I:3/3 C:1/1 P:4/4 M:3/3
How many teeth does a pig have?
44 teeth.
How many teeth does a pig have on its upper jaw?
22 teeth.
How many teeth does a pig have on its lower jaw?
22 teeth.
What is the dental formula of a herbivore (cow, sheep or goat)
I:0/3 C:0/1 P:3/3 M3/3
What is the dental formula for a sheep?
I:0/4 C:0/0 P:3/3 M:3/3
What is the diastema ?
The gap between the front teeth and the premolars is known as diastema.
What can the diastema do?
It can store ingested material while the animal is chewing.
Draw sheep dentition diagram
Read
What, in sheep, is very similar to an incisor and may be considered an incisor ?
The canine tooth
What is dentition
The arrangement of teeth in a particular individual or species.
How many pairs of salivary glands does the mouth have?
The mouth has three pairs of salivary glands.
In the monograstric animal (e.g. pigs), what does the salivary glands secrete ?
In the monogastric animal, the salivary glands secrete an enzyme called amylase.
What does the amylase do?
The amylase breaks down starch to maltose.
How can food be more broken down chemically by amylase?
The more the food is chewed by the teeth, the more it can be broken down chemically by amylase.
What is the secondary function of saliva? What digestive systems does this take place in?
Saliva has a seconday function as a lubricant which wets the food and makes it easier to chew and swallow. This takes place in the monogastric and ruminant digestive systems.
Where is food passed when swallowed.
Food is passed to the oesophagus when swallowed.
How is food prevented from entering the Trachea?
Food is prevented from entering the trachea by the epiglottis.
How is food moved to the stomach along the oesophagus.
Food is moved to the stomach along the oesophagus by peristalsis
What is peristalsis
food entering the oesophagus is moved along to the stomach by muscular contractions, which have a rhythmic, wave-like motion.
Draw the ruminant digestive system
Read
Name two ruminant herbivores
Cattle and sheep are 2 ruminant herbivores.
Name the four chambers of the ruminant stomach.
The rumen, the reticulum, the omasum and the abomasum.
What does the ruminant stomach allow?
The digestion of the complex carbohydrate cellulose which is found in grass, the main contituent of their diet.
What is the main constituent of a ruminant animal’s diet?
Grass.
