chapter 17 – part i
Post on 24-Feb-2016
29 Views
Preview:
DESCRIPTION
TRANSCRIPT
Chapter 17 – Part I
• Alimentary canal• Mouth• Pharynx• Esophagus
Can you sort out the statements into True and False?
Carbohydrates, proteins and fats are all made up of carbon, hydrogen, nitrogen and oxygen.
Fats are made up of smaller units called amino acids
Starch is a large carbohydrate molecule
Starch molecules can be broken down by amylase.
Proteins are made up of one or more glucose molecules
Proteins are important for the growth and repair of cells
How do we break down the food we eat?
1. Mastication/Mechanical
2. Chemical Digestion
teeth
bile
stomach acid
enzymes
The Alimentary CanalThe alimentary canal (or gut) is the tube within the body through which food passes and is processed in various ways
1. Mucosa - protects tissues and carries absorption
2. Submucosa - glands, blood vessels, nerves
3. Muscular Layer - smooth muscle tissue, circular & longitudinal fibers, pushes food (PERISTALSIS)
4. Serosa (serous layer) - visceral perineum, outer covering of the tube, lubricates surfaces (serous fluid)
Layers of the Alimentary Canal
The Mouth
TeethEnamel is the hardest substance in the human body.
Incisors –cutting and chopping food
Cuspid (canine) – sharp and pointed for cutting and tearing food
Bicuspids – cutting and chopping
Premolars – crushing and grinding food
Molars - grinding and mashing food
• Get a mirror and look at a partner’s teeth. Identify each type of tooth – count them
• A dentist would write your dental records as:
I: 2/2 C:1/1 PM: 2/2 M: 3/3.What do you think this means?
Dental Caries
What causes tooth decay?Saliva is slightly alkaline – it’s not that!
When we eat, bacteria in your mouth feeds on the sugar and turns it to acid. The acids wear away the enamel.
Decay has started in the
enamel
NO PAIN
Decay has reached the
dentine
SLIGHTTOOTHACHE
Decay reaches the
pulp
SEVERETOOTHACHE
Decay has spread down to the nerve
rootEXCRUCIATING
PAIN!!
Meth Mouth
Dry mouth –xerostomia (no neutralization of acids)
Shrinking blood vessels
Erosive chemicalCompulsive grindingDesire for sugar
Wisdom teeth
Digestion ‘the breakdown of large insoluble molecules into soluble molecules’
Absorption – only small particles can pass through cells, but large molecules can be broken down into smaller ones
TASK: Copy and complete this diagram into your notes:
starchstarch
starch
starchG
G
G
GUT INSIDE THE BODY (BLOOD)
G
G
G
BEFORE ABSORPTION
GUT INSIDE THE BODY (BLOOD)
AFTER ABSORPTION
Digestive Enzymes There are 3 main types of digestive
enzymes:Amylase breaks starch down into
glucose.Protease breaks protein down into
amino acids.Lipase breaks fats down into fatty
acids and glycerol
Salivary Glands
Saliva is mixed with food during chewing
Teeth assist the mechanical breakdown of food
Saliva contains the enzyme amylase which starts the digestion of food
Saliva contains mucus that keeps the mouth moist and lubricates food for easier swallowing
Digestive Enzymes
Amylase
StarchGlucose
Protease
ProteinAmino Acids
Glycerol
Fatty Acid
Fatty Acid
Fatty Acid
Glycerol
Fatty Acid
Fatty Acid
Lipase
Fat Fatty Acids and Glycerol
Digestive Juices SALIVA
•Salivary amylase
GASTRIC JUICE•Hydrochloric acid•Pepsin (protease)
LIVER •bile
PANCREATIC JUICE•Pancreatic lipase•Proteases (trypsin)
INTESTINAL JUICE•Mucus, various enzymes
Peristalsis
http://nutrition.jbpub.com/resources/animations.cfm?id=1&debug=0
Pharynx nasopharynxoropharynxlaryngopharynx
Esophagusesophageal hiatus is where it penetrates the diaphragm cardiac sphincter at entrance to stomach
top related