9.5 Absorption in the small intestine Flashcards
When does absorbtion begin and in which part of the of the small intestine?
–> What is significant to absorbtion of the small intestine?
Absorbption begins in the jejunum and illieum, and large intestine/
The jejunum does not immediately start absobption, gradual transition between digestion and absorbtion.
The structure of the small intestine play a big role in absorbtion because they contain villi and microvilli.
What is villi, what is microvilli, what are the capilliaries?
Structure/function and importance?
-> structure of the small intestine is made to maximumzie the surface area of the small intestine for effcient nurtrient absrobtion.
Villi = finger like projections (making the walls rigid instead of smooth)
microvilli: smaller finger-like projections
–> capiliaries are the smallest possibl blood vessel, and all nutrients except fats enter the blood stream through capilliaries.
–> once in the capiliaries, it is transported to the the other tissues of the body
How is fat absorbed?
Fat is absorbed through the structure called lacteals. which is a vessel of within the lympathic system.
Digested fats go through the lympatic system before they are transported to the bloodstream.
What are the mechanisms that allow for transportation (the 2 main catergories, and the 3 that fit under one)
Passive transortation:
1) SImple diffusion
2) Osmosis
3) Faciliated diffusion
Active transportation:
What is the pattern of passive transportation
-> No energy used (transporting materials)
-> Down the concentration gradient (from high to low) (until equlibrium)
What are the patterns of active transportation?
-> Transporting materials with the use of ATP energy
-> transfering materials through the cell membrane acorss a special protien
-> Moving up the concentration gradeint (low to high) (Until equilbirium) Using ATP energy
What is the difference between the protein used in faciliated diffusion vs to proteins in active transportation?
Faciliated diffusion uses open channels (“gateways”)
-> physically binds onto substances/molecules on one side and releases them on the other
-> substances do not receive any help going through the protein in faciliated diffusion
While active transportation uses special transport proteins, which are embedded in the cell membrane, each protein has a unqiue sieze and shape letting certain subtances pass through
What type of particles:
Large/unqiuely shape
these protiens aid the particles in moving from the membrance.
What is simple diffusion
A mechanism that allows particles to easily and freely move accross the cell membrane, and no energy is used.
Moves down the concentration gradient therefore it goes from high concentration of paricles to low concenration of particles and the general movement ends when both sides are equal (concentration is equal and distrobuition is equal)
However particles do not stop moving, the general pattern of the movement just ends (at equillibruim, there is an equal rate of movement)
what types of particles are moving through simple diffusion?
-> small and uncharged
What is osmosis
A mechanism that allows water particles to easily and freely move accross a semi-permable membrane, and no energy is used.
Moves down the concentration gradient therefore it goes from high concentration of water to low concenration of water and the general movement ends when both sides are equal (concentration is equal and distrobuition is equal)
However water do not stop moving, the general pattern of the movement just ends (at equillibruim, there is an equal rate of movement)
HOWEVER: how much water molecules there are dependents on how much solutes are in the water.
–> the more solues in the water (dissolves particles) the less water there is, therefore if you have a lot of solutes you need more water, you cannot base water levels simply on how much water there is.
what types of particles are moving through osmosis?
Water
What is faciliated diffusion
The diffusion of molecoles accross a cell membrane via a transport protein, where no energy is used.
Moves down the concentration gradient therefore it goes from high concentration of paricles to low concenration of particles and the general movement ends when both sides are equal (concentration is equal and distrobuition is equal)
However particles do not stop moving, the general pattern of the movement just ends (at equillibruim, there is an equal rate of movement)
The transport protien is uses “open channels” where it acts as a gateway. The protien physically binds to the molecules/ subtances on one side and releases them molecule on the other side, but DOES NOT HELP the particle in moving.
What type of protiens are being transfered?
larger but not too large, and uniquely shaped
What is active transportation?
-> Transporting materials with the use of ATP energy
-> transfering materials through the cell membrane acorss a special transport protien
-> Moving up the concentration gradeint (low to high) (Until equilbirium) Using ATP energy
The transport protein used physically aids the particles while going accross the cell membrane. “actively movig the substances”
What types of particles are they moving?
Large
Charged
