nutrition in humans Flashcards
why do humans and most other animals need to consume food?
to fulfil their energy requirements, as well as obtain the building blocks for the assembly of new molecules, cells and tissues
what are the stages of nutrition?
ingestion, digestion, absorption, assimilation, egestion
what happens during ingestion and which body part is responsible for this process?
food enters the body
mouth
what happens during digestion and which body part(s) is/are responsible for this process?
-large food molecules are broken down into smaller, soluble molecules
-physical (mechanical) digestion
-chemical (enzymatic) digestion
mouth,stomach,small intestine
what happens during absorption and which body part(s) is/are responsible for this process?
-digested food substances pass through intestinal epithelial cells into the blood or lymph by diffusion and active transport
-excess water and mineral salts are absorbed at the colon of the large intestine
small intestine(ileum), large intestine
what happens during assimilation and which body part(s) is/are responsible for this process?
-absorbed food substances are transported in the bloodstream to all parts of the body
-utilised by cells to make new complex substances or broken down to release energy
liver
what happens during egestion and which body part(s) is/are responsible for this process?
undigested food is passed out of the body
rectum, anus
what is assimilation?
it is where nutrient-rich blood in the small intestine is first transported to the liver to regulate the concentration in the blood prior to distribution, as well to remove any potential toxins absorbed before it circulates broadly in the body
how does our blood glucose rise above normal range?
when consuming a rich in carbohydrates meal, the glucose present and absorbed will raise the level of blood glucose to above the healthy range. this causes a series of events where the pancreas and liver have to work to bring the blood glucose level back down to healthy levels
how does our blood glucose drop lower than healthy range?
when we do vigorous physical activities or take
on a long period of fasting, our blood glucose level drops and this triggers a series of events where the pancreas and liver have to work to bring the blood glucose level up back to healthy range
how is the blood glucose brought down to healthy range?
pancreas secretes insulin
excess blood glucose in converted to glycogen and stored in the liver
how is the blood glucose brought up to healthy range?
pancreas secretes glucagon
glycogen is broken down into glucose and released into the bloodstream
what happens when our liver and pancreas do not respond to the fluctuating blood glucose levels?
they have diabetes mellitus
what happens after the amino acids from the small intestine have been transported throughout the body?
excess amino acids will be deaminated in the liver then converted to urea before bring excreted in urine
