Human nutrition Flashcards
What is digestion?
Digestion is the chemical (enzymes) and physical breakdown of food into small soluble pieces.
What is the function of digestion?
To ensure food can be absorbed (into bloodstream)
What does autotrophic mean?
An organism that can make its own food (plants)
What does heterotrophic mean?
Organisms that cannot make their own food (carnivores, herbivores, omnivores)
What is a saprophyte?
Organism that takes in nutrition (food) from a dead source (fungi)
What are the 5 stages in human nutrition?
- Ingestion (take in food)
- Digestion
- Absorption (into bloodstream)
- Assimilation (how cells use the absorbed food)
- Egestion (getting rid of undigested food)
Name an example of physical digestion in the mouth
Teeth grind food
Name all the types of teeth found in the mouth
Incisors 2/2, canines 1/1, pre-molars 2/2, molars 3/3 (32 teeth total)
How does chemical digestion occur in the mouth?
Saliva - contains an enzyme called amylase - starch is broken up using amylase into maltose
What occurs in the oesophagus?
A bolus (ball) of food is formed and swallowed.
Bolus of food enters the oesophagus by epiglottis (cartilage to ensure food enters the right pipe).
Food is moved by muscular action called peristalsis.
Food enters the stomach by the cardiac sphincter muscle
What shape is the stomach?
J - shaped muscular bag
How does physical digestion occur in the stomach?
Stomach churns food.
Name the 3 gastric juices
Hydrochloric acid (HCL), pepsinogen, mucous
What are the qualities of hydrochloric acid?
pH 2 (acidic), kills bacteria, activates pepsinogen into pepsin
What are the qualities of pepsinogen?
Activated into pepsin by HCL and chemically digests polypeptides into peptides (protein)
What is the function of mucous in the stomach?
Lining of stomach muscle preventing self digestion and ulcers
What happens to food in the stomach after 1 and a half hours
Chyme is formed