Digestive System Flashcards
What does autotrophic mean?
Makes own food
Autotrophic organisms produce their own food through processes like photosynthesis or chemosynthesis.
What is photosynthesis?
Uses light energy
Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.
What is chemosynthesis?
Uses chemical energy
Chemosynthesis is the process by which certain organisms convert carbon molecules and nutrients into organic matter using the oxidation of inorganic molecules.
What is heterotrophic nutrition?
Takes in food
Heterotrophic organisms cannot produce their own food and rely on consuming other organisms.
What are the stages in nutrition?
Ingestion, Digestion, Absorption, Egestion
These stages outline the process food undergoes from intake to elimination.
What is digestion?
Food is broken down
Digestion involves both mechanical and chemical processes to break down food into nutrients.
What is egestion?
Unabsorbed material is removed
Egestion is the elimination of undigested food and waste from the body.
What does ingestion refer to?
Food is taken into the digestive system
Ingestion is the first step in the digestive process.
What is the role of mechanical digestion?
Crushing and grinding of food
Mechanical digestion increases the surface area of food, making it easier for enzymes to break it down.
What is the process of chemical digestion?
Food is broken down by acid and enzymes
Chemical digestion involves the use of digestive juices to break down food into simpler substances.
What is absorption in the context of nutrition?
Digested food is taken into the bloodstream
Absorption mainly occurs in the small intestine and some in the colon.
What is the alimentary canal?
A long tube that goes through the body, starting at the mouth and ending at the anus
The alimentary canal is part of the digestive system and is responsible for processing food.
Define herbivore.
Eats plants
Herbivores are animals that primarily consume plant-based foods.
Provide an example of a herbivore.
Rabbit
Rabbits are classic examples of herbivorous animals.
Define carnivore.
Eats animals
Carnivores are organisms that primarily consume meat.
Provide an example of a carnivore.
Fox
Foxes are examples of carnivorous animals that primarily hunt and eat other animals.
Define omnivore.
Eats plants and animals
Omnivores have a diverse diet that includes both plant and animal sources.
Provide an example of an omnivore.
Badger
Badgers are examples of omnivorous animals that consume a varied diet.
Fill in the blank: Most water is absorbed in the _______.
Colon
The colon plays a crucial role in reabsorbing water from indigestible food matter.
What is the function of incisors?
Cut and slice food
Incisors are the front teeth used for cutting food.
What do canines do?
Grip and tear food
Canines are pointed teeth located next to incisors.
What is peristalsis?
The rhythmic contraction and relaxation of the wall of the alimentary canal that moves food down the canal
Fibre stimulates peristalsis.
What is the role of saliva?
Contains lysozyme that kills microorganisms
Saliva also helps in the initial chemical breakdown of food.
What occurs during the mechanical breakdown of food?
Teeth grind and crush food
This process includes actions by incisors, canines, pre-molars, and molars.
What is the function of the sphincter between the oesophagus and the stomach?
Stops movement of food
A sphincter is a collection of muscle fibres that encircle a tube.
What type of environment does the stomach have?
Alkaline environment
This environment is necessary for digestive processes.
What is the dental formula for teeth?
1?/2 C’/1 P²/ M³
This formula represents the types and numbers of teeth in a human mouth.
Which enzyme digests starch to maltose?
Amylase
This enzyme is present in saliva and initiates carbohydrate digestion.
What is the oesophagus?
A muscular pipe that moves food to the stomach
It is part of the alimentary canal.
Fill in the blank: The _______ stimulates peristalsis.
Fibre
What is the primary function of the liver?
The liver is a metabolic sorting station that detoxifies and maintains homeostasis.
The liver processes nutrients, chemicals, toxins, and drugs that we ingest.
What does the hepatic vein transport?
Nutrients and urea from the liver to the heart.
This transport is essential for further processing and elimination of waste.
What role does the aorta play in the circulatory system?
Transports nutrients and urea away from the heart.
The aorta is the main artery that carries blood from the heart to the rest of the body.
What substance is transported to the kidneys?
Urea.
Urea is a waste product formed from the deamination of amino acids.
What is formed in the liver?
Cholesterol.
Cholesterol is crucial for cell membrane structure and hormone synthesis.
What is deamination?
The breakdown of amino acids with the production of urea.
This process is essential for removing excess nitrogen from the body.
What is the main function of the duodenum?
Main location for digestion.
It also makes fibrinogen and receives bile from the gall bladder.
What type of environment does the duodenum have?
Alkaline environment.
This helps in neutralizing stomach acids and optimizing enzyme activity.
What are villi?
Finger-like outgrowths in the ileum that increase surface area for absorption.
Each villus is covered in microvilli, further enhancing absorption.
What is absorbed by the ileum?
Food broken down into basic building blocks, glucose, and amino acids.
The walls of the small intestine are one cell thick to aid absorption.
What is the role of lacteals in the ileum?
Drain digested fats into the lymphatic system.
They transport fatty acids and glycerol, returning them to the bloodstream.
What does the colon reabsorb?
Water from waste, forming faeces.
Insufficient time for reabsorption can lead to diarrhea.
What is the result of insufficient water reabsorption in the colon?
Diarrhea.
The opposite condition, constipation, results in hard stools.
What function do symbiotic bacteria in the colon serve?
Make vitamin K and digest cellulose.
They also prevent harmful microorganisms from growing.
What is the caecum?
A part of the colon that contains the appendix.
The appendix is considered a vestigial organ.
What is appendicitis?
Inflammation of the appendix due to lodged food or faeces.
Symptoms include pain, nausea, vomiting, and fever.
What is the function of the rectum?
Stores faeces.
It plays a crucial role in the final stages of digestion.
Components of a balanced diet include _______.
[Carbohydrates]
A balanced diet also typically includes proteins, fats, vitamins, and minerals.
What are the main categories of nutrients?
Proteins, Fats, Vitamins, Minerals, Water, Fibre
Each category plays a crucial role in maintaining overall health.
What is the role of Fibre in the diet?
Stimulates peristalsis, soaks up toxic chemicals and cholesterol, may prevent obesity
Fibre helps in digestive health and weight management.
What factors determine the amount of food a person requires?
Age, activity, gender, health
These factors influence nutritional needs and caloric intake.
How is BMI calculated?
BMI = body weight in kg / (height in m)²
BMI is a common measure to assess body weight relative to height.
What BMI values indicate being overweight and obese?
Overweight: BMI above 25; Obese: BMI over 30
These classifications are associated with various health risks.
What is Anorexia Nervosa?
An eating disorder characterized by persistent restriction of energy intake, intense fear of gaining weight, and distorted body image
It can lead to serious health consequences such as cardiac problems and electrolyte imbalances.
What are the symptoms of Anorexia Nervosa?
Low body weight, fear of gaining weight, disturbance in body image, undue influence of body shape on self-evaluation
Symptoms can severely impact physical and mental health.
How is Anorexia Nervosa treated?
Psychiatric input: counselling and medication; medical input for physical problems
Treatment often requires a multidisciplinary approach.
What is Bulimia?
An eating disorder characterized by recurrent binge eating followed by compensatory behavior to prevent weight gain
Binge episodes are often accompanied by feelings of lack of control.
What are the four food groups?
- Cereals, breads, potatoes (6+ servings per day)
- Fruit and vegetables (4+)
- Milk, cheese and yoghurt (4)
- Meat, fish and poultry (2)
These groups represent a balanced dietary intake.
What is the role of Amylase?
Breaks down starch to maltose; produced in salivary glands and pancreas; acts in mouth and duodenum
Amylase is crucial for carbohydrate digestion.
What is the optimal pH range for Amylase activity?
pH 7-9
This pH range is necessary for effective enzymatic activity.
What is Pepsin?
An enzyme that breaks down protein to peptides and amino acids
Pepsin is active in the stomach at a pH of 2.
What is Lipase?
An enzyme that breaks down lipids to fatty acids and glycerol
Lipase is produced in the pancreas and acts in the duodenum at a pH of 7-9.
Where is Pepsinogen produced?
By the stomach lining
How is Pepsinogen activated?
By acid into its active form
In which part of the digestive system does Pepsin act?
In the stomach
What is the optimal pH for Pepsin activity?
pH 2
Where is Lipase produced?
In the pancreas
In which part of the digestive system does Lipase act?
In the duodenum
What is the optimal pH for Lipase activity?
pH 7-9
