Human Nutrition Flashcards
What is digestion
The process of breaking down large, insoluble particles, into small soluble molecules
What is absorption
Small, soluble molecules of food are absorbed from the alimentary canal into the blood
Defaecation
Indegistable food residues are removed from the body , in the form of fecies
What is the digestive system
Responsible for the ingestion , digestion , absorption and defaecation stages of nutrition.
What can organs be seperated into
Alimentary canal and accessory digestive organs
What is the alimentary canal also known as
The gut
Describe the alimentary canal
8,5 m long
Continuous muscular tube running through the body
Has an opening at both ends, mouth and anus
Not a simple tube , each section has different functions to carry out
What does the alimentary canal do
Digests food -Breaks food down into smaller fragments
Absorbs the digested fragments through its lining into the blood
What are the alimentarycanal organs
Mouth, oesophogus, stomach, small intestines, large intestines which lead to the anus
What are the accessory organs
Teeth, tounge , and glands (salivary, liver and pancreas)
What do the accessory organs do
Each have their own function of Deliver substances to the alimentary canal , food doesn’t go in or out
What does the mouth do
Teeth chew the food , and mix it with the saliva . The saliva helps to digest the starch in food and makes it easier to swallow the food
What does The oesophogus do
The food goes down the oesophogus to the stomach in a few seconds
What does the stomach do
The food is mixed with gastric juices and other chemicals to help break down the food
What does the small intestine do
The food that is a thick, milky mixture moves slowly through. More chemicals are added from the liver and pancreas. Some of the dissolved food passes through the wall of the small intestine into the blood . 6 to 7m long. When all the food is through , the useful substances are in the blood
What does the large intestine do
Stores the solid waste substances that the body can’t use. Water is taken out of the undigested waste. The water goes into the blood , solid waste goes into the rectum.
What does the appendix do
Has no function. In animals it’s used to digest grass and other plants humans don’t eat
What does the rectum do
Stores solid waste for a short time
What does the anus do
When the rectum is full , solid waste called faeces passes out of the anus
What does the accessory organ , the liver do
Produces biale, which is stored in the gall bladder
What does the pancreas do (accessory organ)
Helps with blood sugar
What is the chewing of food into soft pulp known as
Mechanical digestion , but the food is also made moist from saliva secreted by the 3 pairs of salivary glands
What does saliva contain
Mucin, lysozyme , enzyme that digests starch and a lot of water.
What does water in the saliva do do to the food
Softens and moistens the food
What does the mucin in the saliva do
Mucin is a sticky substance that sticks the food particles together to make a ball of food (bolus) and it also makes food slippery to swallow
What does the enzyme in saliva do
Breaks down starches, called chemical digestion
What does the lysozyme in saliva do
Protects the mouth from infection by killing bacteria
What does the tongue do
Mixes food with saliva
Moves food around mouth and pushes it between
What happens when you swallow food
It passes through your pharynx (throat) and into a tube called the oesophogus
What tube carries food from the throat to the stomach
The oesophogus
Desribe the oesophogus layers
The wall consists of a number of layers ( like all other parts of the alimentary canal) in these layers is smooth muscle which allows a process called peristalsis to occur
Where does the lower end of the oesophogus end
In an elastic , bag shaped organ the stomach
What do the walls of the stomach consist of
3 layers of involuntary muscles (you can’t control these )
What do involuntary muscles do
Play a very important role in breaking down food into a liquid and mixing it with gastric juices (churning) during mechanical digestion . You can’t control them
How is gastric juice secreted and what does it contain
Gastric Juice is secreted by the gastric glands in the wall of the stomach. It contains enzhymes which act on proteins and hydrochloric acid
What does the hydrochloric acid do
Makes the contents of the stomach acidic which kills the germs in food and helps the enzhymes of the stomach to work
What is mucin
A slimy substance that lines the stomach wall. Protects the stomach from hydrochloric acid.
What happens in the stomach and what does it act as
A temp storage tank for food, and a place where foods broken down into liquid pulp (chyme) , protein breakdown begins in the stomach.
What are absorbed in the stomach
Alcohol and painkillers are absorbed into the stomach , but not many substances are
Describe the small intestine and what happens in it
Narrow tube about 6-7 m long. Digestion of food takes place here. The simple, soluble units of food can then be absorbed.
The small intestine is divided into 3 parts , what are they and what are the sizes
The duodenum (25cm) The jejunum (2,5m) The ileum (4m)
What are leading into the duodenum
Ducts which are small tubes from the liver and the pancreas.
How does biale go into the duodenum
Via the bile duct
What is bile
Watery , alkaline substance. Used to neutralize the acidic chyme when it comes into duodenum from the stomach. It emulsifies fat( breaks small lumps of fat into smaller droplets) making it easier to digest.
What does the pancreas make
Pancreatic juice, which is secreted via a duct in the duodenum
What does pancreatic juice contain
Enzhymes that digest proteins , fats and starch. Also helps to neautrslize acidic chyme
From the duodenum, where does digestion continue to
The jejunum. Where food is moved slowly by peristalsis (it’s mixed well as it moves )
Where does the final step of digestion take place
The ileum. The enzymes needed for the last step of digestion are on the lining of the ileum.
When can foods be absorbed in the ileum
When foods are broken down into their simplest, soluble units , they can dissolve in water and be absorbed in the ileum.
How is food absorbed
Through the innner most lining of the ileum = mucosa
Describe the mucosa of the ileum
It has Folds, the inner of the mucosa has millions of small projections called villi.
What are the cells of the villi folded to form
Microvilli
What increases the surface area of the ileum
The folds, the villi and the microvilli
What does each villus have
Lots of blood vessels surrounding the central lacteal
What Happens when the simple, soluble units are absorbed
The blood carries them to the liver
What is lymph
Fluid drained by the lymph vessels from the cells and tissues
What happens when lipids are digested
Their products are absorbed by the lacteal and are carried in the lymph in the lymph vessels
What do lymph vessels do
Join the blood system near the left shoulder
What is the large intestine also known as
The colon
What is the main function of the large intestine
To adorn water from the remaining material in your intestines. Also absorb dissolved vitamins and minerals
What happens when the water decreases in the large intestine
The material becomes drier and more solid until it forms faecss
Where is faces stored
In the last part of the large intestine , the rectum and leaves the body through the anus
Where does digested food go
All the products of digestion ( except fats) move into the blood capillaries of the villi
Where do the blood capillaries lead into
Into a vein that goes to the liver
What are carried in the blood from the liver to where it is needed in the body
Glucose and other nutrients are carried in the blood from the liver to where it’s needed in the body
What can the liver store
Excess food as glycogen
How are products of fat digestion carried away from the villi
By the lymphatic system
Where does lymph drain into the blood
Near the left shoulder
How are fats carried to the liver
Carried by blood
What does the body do if it needs more energy
Liver changes fat into glucose
What can the liver store
Excess fat
What can also carry fat from the liver to other organs where it is stored
Blood
What are the 3 main classes of food
Carbohydrates, proteins , fats
There are many nutrients, what are they
Vitamins , minerals, fiber, water . They are essential part of the diet but needed in smaller quantities
What are carbohydrates
Starches and sugars used by the body for energy
What are carbs made of
Carbon, hydrogen, and oxygen atoms
What can the sugar found in diets be
Either sucrose (table sugar) or fructose (fruits)
What is the cheapest most readily available source of energy
Carbs
Why is carbs the most readily available energy
It’s easy for our body to break down carbs to release energy
What is carbs used with in respiration
Carbs is used with oxygen in respiration to form carbon dioxide and water
What happens if you eat to little carbs
You become tired and restless
What happens if you eat to many carbs
Obesity, as the excess is stored as fat or glycogen in the liver
What are proteins made up of
Amino acids
What are proteins
The building blocks for growth and repair of damaged tissues
Where are proteins gained from
Mostly meat , but beans eggs and dairy products also. There is a variety and it’s good to eat a variety and they’re made of different amino acids
How many amino acids can’t the body make
The body can’t make the 9 essential amino acids
How many amino acids can the body make
The body can make 11 non essential amino acids
What are amino acids made up of
Carbon, hydrogen, oxygen and nitrogen.
What do carbs and proteins have in common
People need a variety
What type of people need a lot of protein and why
Children and pregnant, it’s important for grotwth
What are excess amino acids converted into
Glycogen in the liver and muscles
What are fats essential to the body as
A reserve energy store
How do fats help in temperature regulation
By insulating the body
What is fats made of
Hydrogen, carbon and oxygen (but in different proportions to carbs)
What happens when fats are used as an energy source
They give off twice as much energy as carbs
What fats do animals give us
Saturated fats (meat, dairy, egg yolk)
What fats do plants give us
Unsaturated fats (oils, fruit, and seeds)
What fats are better to eat
Unsaturated fats , but it’s important to eat saturated fats , as this is easier to store as a reserve food source
What can’t vitamins be used as
For energy , not can they be used as building blocks like carbs , proetiens and fats
What are vitamins important for
Chemical reactions that can’t be synthesized
What does vitamin A do. Where is it found
Keeps skin, bones and eyes healthy. Prevents infections (threat and nose especially)
Fish liver oil, liver, green veggies , milk and carrots
What does vitamin B do. Where is it found
Growth , release of energy from food , healthy blood , eyes skin
Yeast, whole wheat , break,green veggies, eggs, livers, milk, cheese, meat, fish
What does vitamin C do. Where is it found
Helps wound healing , healthy teeth and gums, prevents infections (nose and threat)
Citrus fruit, green veggies , tomatoes , potatoes
What does vitamin D do. Where is it found
Healthy bones , teeth
Liver, butter, cheese, eggs, fish, made by skin when exposed to sun
What does vitamin E do. Where is it found
Nescersary for fertility in woman
Lettuce, wheat germ, eggs, some plant , animal oils
What does vitamin K do. Where is it found
Nesearry for blood clotting
Green leaves, strawberries, fish
Lack of vitamin b
Causes Beri beri . Paralysis of the limbs (arms and legs)
Pernicious anemia . Red blood cells aren’t properly formed.
Lack of vitamin C
Scurvy. Results in soft gums , loose teeth and poor wound healing
Lack of vitamin D
Rickets. Soft or weak bones , legs that bow out
What are some minerals
Salt, iron, calcium, magnesium, potassium, iodine that are essential for the body
What does lack of salt cause
Muscle cramps
Where is iron found
Read meats and egg yolks , its nesseacry for haemoglobin (which carries oxygen in red blood cells )
Calcium phosphate
For strong bones and teeth
Sodium potassium
For cellular function
Idodine
For making thyroxine in thyroid glands (hormone) . Thryroxine regulates metabolism
Water
Essential part of cyptoplasm
Used to transport different substances around the body, mainly in solution in the blood
Digestion takes place in water
How much body weight does water take up
2/3
What does fiber consist of and what’s in known as
Known as roughage . Consist of plant cell walls .
How do you get roughage
By eating fruit, vegetables or anything made from a plant. Bread (wheat) you get roughage
Why do our bodies struggle to digest fiber
Made of cellulose
How is fiber digested
Some bacteria are able to digest cell walls. This breaks it down into fatty acids (not fat) which are absorbed by large intestine
What happens if roughage isn’t digested
Passes through the gut , scrubs the gut clean . Keeping colon healthy
What does fiber prevent
Constipation
How can we have a balanced diet
By eating a variety of carbs, fats, minerals
What is malnutrition
Lack of food nutrition. Incomplete diet , not getting required nutrients
How is malnutrition caused
By eating to little, or to many of the wrong things . Can cause death and ill health
What is kwashiorkor
Difficiency of protein in South Africa commonly
Oedema , chubby cheeks, peeling skin, colour / hair loss, slow or no growth , swollen stomach, hands and feet
Weakened child becomes victim to other diseases
Marasmus
General lack of food and nutrients , starvation especially in young children
Severe weight loss , extreme weakness , diorehia , face of old person , thin, potbelly , hungry , miserable
Easily contracts other diseases
Scurvy
Bleeding gums
Lack of vitamin C , no fresh fruits or vegetable
Goitre
Lack of iodine in diet
Thyroid gland in neck swells
Pellagra
Lack of vitamin niacin from vitamin B
Diorehia , skin disease
Marks in neck shaped like necklace
Rickets
Lack of vitamin D or phosphorus and calcium in diet
Soft bones that change shape , become bent because of weight of body and muscles pulling them
Anorexia nervosa
Compulsive exercise
Plyschologically rooted , vulnerability and loss of control
Starving because of fat self image
Starvation , hair loss , muscle wasting , fine hair , dry skin , sleep loss
Bullemia
Binge on huge quantities of food , induce vomit after
Weight loss fast
Fasting pills, avoidance tactics, laxatives (Like anorexia)
Obsessive approach to food , stomach cramps , bathroom, puffy face(stomach acid) kidney damage , exhaustion , dental problems
Obesity
Assesive eating that affects organs , related to emotional feelings, eating in secret , past the stage of satisfying hunger . Poor circulation, shortness of breath , body odor , bad breath
What are fad diets
Offer short term solutions , quick fix . Promise fast results with minimum effort , too good to be true claims, offer no guidelines for management after. Not individually planned.
What is ingestion
The process of taking food , drink or another substance into the body by swallowing
