nutrition in humans Flashcards
(10 cards)
What are the 3 roles of hydrochloric acid is gastric juice?
- Destroy microorganisms in ingested food
- Activate pepsinogen into pepsin
- Provide acidic environment hence optimum pH for pepsin to work in
What is chemical digestion?
Chemical digestion is the enzymatic breakdown of large and complex nutrient molecules to
smaller, simpler molecules that are small enough to diffuse across partially permeable cell
surface membranes to be absorbed into body cells.
What processes release nutrients from the food we eat?
Digestion, absorption
and assimilation.
Where does peristalsis occur?
Peristalsis occurs throughout alimentary canal from opening of oesophagus to anus.
What is ingestion?
Ingestion is the intake of food into the alimentary canal through the mouth.
What is physical digestion?
Physical digestion is the mechanical breakdown of large pieces of food into smaller pieces
of food to increase surface area to volume ratio for enzymatic digestion.
Why do humans need to eat?
Humans need to eat to obtain nutrients and energy for growth, repair, and maintenance.
State an example when accessory organs in our digestive system
play important roles in the digestion and assimilation of food.
The liver
produces bile, which is involved in fat digestion, and the pancreas produces digestive juices
and hormones to regulate our blood glucose concentration.
How does the circular and longitudinal muscles in the alimentary canal work?
They work antagonistically.
Circular muscles: contract
Longitudinal muscles: relax
The lumen of alimentary canal becomes narrower to push food forward
Circular muscles: relax
Longitudinal muscles: contract
The lumen of alimentary canal becomes wider to allow food to enter
What is peristalsis?
Peristalsis is rhythmic wave-like contractions of the circular and longitudinal muscles of the walls
of the alimentary canal to mix and propel the contents along the alimentary canal.
