Digestive System Flashcards
What is digestion?
the conversion of food into simple, soulble chemicals capable of being absorbed through the intestinal lining into the blood to be used by body cells
What is ingestion?
taking in food, drink and drugs by the mouth
What is absorption?
taking up of substances to be used by the body cells and tissues
What is egestion?
the process involved in eliminating waste material from the body such as faeces
What is peristalsis?
the contracting and relaxing of the smooth tissue in the intestine walls to push the food bolus through
Name the 12 parts of the digestive system
mouth phaynx salivary glands oesophagus stomach duodenum ileum colon liver pancreas gall bladder anus
How is food digested in the mouth?
mechanical digestion - food i mixed with saliva, chewed and rolled into a small ball (a bolus) and swallowed
salivary amylase begins the digestion of carbs and lubricates the mouth
Which digestive enzyme is secreted from the salivary glands, into the mouth?
salivary amylase
Which digestive enzyme begins the digestion of carbohydrates in the mouth?
salivary amylase
How does the oesophagus transport the food bolus from the mouth to the stomach?
by peristalsis (muscular contractions)
what is the name of the flap that covers the opening of the trachea during swallowing to prevent food entering the respiratory system?
epiglottis
Roughly how long can food stay in the stomach for?
about 3 hours
How does digestion continue in the stomach?
the stomach walls roll and churn the food around and pour on secretions from gastric glands (gastric protease and hydrocholric acid), resulting in chyme
What is the first part of the small intestine called?
the duodenum
How is digestion continued in the duodenum?
the liver and pancreas pour their juices into the duodenum, and the duodenum contains glands that secrete enxymes that continues the digestive process on proteins, carbohydrates and fats
After the duodenum, what is the rest of the small intestine called?
the ileum
What happens in the ileum?
nutriends from the digested foods are absorbed into the blood
Which type of cell lines the small intestine?
columnar cells
What are the 2 parts of the large intestine?
colon and rectum
What is the role of the large intestine?
it slows down the passage of food waste so that water can be reabsorbed and the faeces becomes semi-sold
What does faeces contain?
cellulose from plant cell walls (from fruit/veg)
dead bacteria
cells scraped off from the gut lining
What role does the liver play in digestion?
it produces bile that goes into the duodenum that causes the emulsification of fats
The liver also removes glucose from the blood coming from the small intestine and converts it to glycogen for storage
Surplus amino acids are broken down in the liver to form glycogen and urea
What’s the role of the pancreas in digestion?
it secretes pancreatic enzymes that help break down protein, fat and carbohydrates into amino acides, glucose/simple sugars and fatty acdids/glycerol
It also makes insulin that is needed to metabolise glucose and glucagon that releases stored glucose
What does salivary amylase do?
turns carbohydrate ito dissaccharides
What does protease do?
turns protein into amino acids and peptides
What does hydrochloric acid do?
kills bacteria in raw food
What do proteases do?
turn proteins into amino acids
What do bile salts do?
emulsify fats
What does lipase do?
turns fats into fatty acids and glycerol
What does amylase do?
turns carbohydrates into glucose
Where in the digestive system do you find salicvary amylase?
the mouth
Where in the digestive system do you find protease and hydrocholric acid?
the stomach
Where in the digestive system are bile salts secreted from?
the liver
Where in the digestive system are the enzymes lipase, amylase and protease secreted from?
the pancreas
Identify 5 major products of digestion
peptides / amino acids sugars (glucose) glycerol fatty acids fats
What does our body need peptides and amino acids for?
they are important in making enzymes, hormones, plasma proteins and the growth and repair of cells
What does our body need sugars (glucose) for?
It’s used in internal respiration to release energy
What does our body need glycerol for?
it’s used for energy or reconverting fatty acids into a form of fat that can be used
What does our body need fatty acids for?
they’re used in internal respiration to release energy for metabolic processes
What does our body need fat for?
it’s stored under the skin and around organs, for long-term energy stores
Name 3 disorders of the digestive system
Ulcers
Hepatitis
Coeliac Disease
What are ulcers?
localised inflammation that has destroyed a small area of skin, producing an open sore (mainly foun in the mouth and stomach)
What causes an ulcer?
the bacterial - helicobacter pylori, or non-steroid anti-inflammatory drugs
What are the symptoms of a gastric ulcer?
stomach pain, indigestion, heart burn, loss of appetite, feeling sick
What is hepatitis?
an, inflammation of the liver caused by viruses or chemical substances
What are the types of hepatitis and their causes?
A - caused be consuming food and drink contaminated with the poo of an infected person
B - spread in the blood of an infected person
C - spread through blood to blood contact with an infected person
D - only affects people with hep B, spread through blood to blood or sexual contact
E - associated with consumption of raw or undercooked pork meat and shellfish
Alcoholic hepatitis - caused by drinking excessive amounts of alcohol over many years
What are the symptoms of hepatitis?
nausea, vomiting, lack of appetite, jaundice (yellow skin), passing of dark brown urine
What is Coeliac disease?
An auto-immune disease wher eyou have an intolerance to gluten, that triggers an immune response
What causes Coeliac disease
genetics, where the body’s defence against infection mistakenly sees gluten as a threat to the body and damages the surface of the intestines, disrupting it’s ability to absorb nutrients from food
What are the symptoms of coeliac disease?
diarrhoea, abdominal pain, flatulence, bloating, indigestion, constipation, fatigue, malnutrition, nerve damage, unexpected weight loss
