Human Nutrition Flashcards
Ch 28
Herbivores?
Animals that feed on plants
Carnivores?
Animals that feed on animals only
Omnivores?
Animals that feed on plants & animals
Eg of herbivore?
Sheep
Eg of carnivore?
Cats
Eg of omnivore?
Humans
Nutrition?
Way in which an organism gets and uses its food
2 types of nutrition?
Autotrophs & Heterotrophs
Autotrophs?
Make their own food
Heterotrophs?
Can’t make their own food, take in food from environment
Eg of autotroph?
Plants making food by photosynthesis
Eg of heterotroph?
Animals
Types of heterotrophs?
Parasites & Saprophytes
Parasites?
Food from a live source
Saprophytes?
Food from a dead source
Eg of parasite?
Fleas, disease-causing bacteria
Eg of saprophyte?
Bacteria + fungi that cause decay
Digestion?
The physical + chemical breakdown of food
Where does digestive system start & end?
Starts at mouth,
Ends at anus
What are attached to digestive system?
Associated glands
Name 3 associated glands?
Salivary glands,
Liver (+ gall bladder)
Pancreas
Name 4 processes in human nutrition?
Ingestion,
Digestion,
Absorption,
Egestion
Ingestion?
Taking in of food into digestive system. When food is placed into mouth.
Digestion?
Breakdown of food
Absorption?
When digested food passes from digestive system and enters into the blood
Egestion?
Removal of undigested/unabsorbed waste from the digestive system/human body
2 types of digestion?
Physical & Chemical
Physical digestion?
Mechanical breakdown of food
When does physical digestion take place?
When we chew food or churn it in stomach
What does physical digestion do?
Increases surface area so chemical digestion can efficiently take place
Chemical Digestion?
Breakdown of food using enzymes
Types of teeth?
Incisors,
Canines,
Premolars,
Molars
Function of incisors?
Cut + slice
Function of canines?
Grip + tear
Function of premolars?
Crush + grind
Function of molars?
Crush + grind
Where are incisors?
Front of mouth
What are canines like?
Long, pointed, fang-like
What are premolars like?
Large, flat surfaces
Where are molars?
Back of jaw
Dental Formula?
2(I 2/2 C 1/1 PM 2/2 M 3/3)
Upper numbers in dental formula =?
No. of teeth on one side of upper jaw
Lower numbers in dental formula =?
No. of teeth on same side of lower jaw
Where does mechanical digestion take place?
Mouth
How does mechanical digestion take place?
Chewing + grinding of teeth on food
Where does chemical digestion take place?
Mouth
How does chemical digestion take place?
By action of enzyme amylase
Where is amylase found?
In saliva
Saliva contains?
Water,
Salts,
Mucus,
Lysozyme,
Amylase
pH of mouth?
7
Function of epiglottis?
Closes over trachea/windpipe and ensures food passes down the oesophagus
Function of oesophagus?
Carry food to stomach by an involuntary wave of muscular contraction called peristalsis
Peristalsis?
Wave of muscular action in the walls of the alimentary canal that moves the contents along
Can humans digest cellulose?
No
Eg of fibre source?
Wholemeal bread, cereals, fruit/veg
What does fibre store/absorb?
Water
Fibre causes what to expand?
Unabsorbed waste
What disease does fibre reduce the risk of?
Colon cancer
What’s the stomach?
Muscular bag that holds + digests food
Protease?
An enzyme that digests protein
What’s pepsinogen?
Inactive enzyme
HCI stands for what?
Hydrochloric acid
Hydrochloric acid gives stomach a pH of what?
1-2
Contraction of stomach walls helps what?
Churn + digest food mechanically,
Turns into thick soupy mixture called chyme
When does chyme leave stomach?
In small amounts when a muscle at the base of stomach opens briefly
What hormone does pancreas secrete?
Insulin (+ digestive materials)
Pancreatic juice consists of what?
Salt sodium-hydrogen carbonate
What does pancreatic juice do?
Neutralises chyme from stomach
Where is liver located?
Under diaphragm
Functions of liver?
- Break down RBC’s
- Make bile (digestive function)
- Converting excess cabs to fat
- Stores glycogen
- Storing Vitamins Eg: A+D
Bile is formed from what?
Remains of damaged RBC’s
Colour of bile?
Yellow/green
Bile consists of?
Water,
Bile salts,
Bile pigments
Does bile have enzymes?
No
Where is bile made?
Liver
Where is bile stored?
Gall bladder
Where does bile enter and through where?
Enters duodenum through bile duct
Functions of bile?
- Impulsifies lipids
- Neutralises chyme from stomach
- Excrete pigments, made from damaged RBC’s
How does bile increase surface area?
By breaking down large fats+oils into droplets.
3 parts of small intestine?
Duodenum,
Jejunum,
Ileum
Function of duodenum?
Carries out digestion
Function of ileum?
Absorb nutrients
Function of Villus/Villi
Increase surface area for absorption
Food absorbed by (villus/villi)
Diffusion
Adaptations of villi for absorption?
- Large numbers increase SA
- Large numbers of microvilli increase Sa
- Walls only one cell thick
- Have rich blood capillary supply
What’s deamination?
Amino acids not used by body, broken down in liver, forming urea
What’s inside each villus
Lacteal
What liquid does each lacteal contain?
Lymph
What’s transported by lymph?
Fats
What are absorbed into cells of villus lining?
Fatty acids + glycerol
Adaptations of the Ilim (small intestine) for Absorption
- very long
- has numerous villi + microvilli
- walls of villi very thin
- rich blood capillary supply to carry water-soluble products away
Functions of large intestine?
- absorption of water
- egestion
- perystalsis
- absorb vitamins
Below large intestines junction with small intestine is what?
Caecum
What’s found at end of caecum?
Appendix
What’s vestigal?
Organs that have lost former use
What does colon do?
Reabsorbs water,
Produces vitamins B+K
What’s egestion?
Removal of undigested waste
What’s a balanced diet?
Contains all required food types in the correct proportions
Amount of needed food depends on?
Age
Activity levels
Gender
Health
7 components of balanced diet?
Carbohydrate
Protein
Lipid
Vitamins
Minerals
Fibre
Water
Foods containing similar nutrients arranged into 4 food groups?
Cereals Breads Potatoes,
Fruit Vegetables,
Milk Cheese Yoghurt,
Meat Fish Poultry
Food pyramid?
Suggested servings for each food group