Digestive Physiology Flashcards
(59 cards)
What is one function of vasopressin?
this is a hormone that controls the amygdala
What region of the brain is the amygdala?
controls fear
What are heterotrophs?
eat other organisms for energy, instead of making it
What can’t be absorbed is…
excreted
How do animals gain nutrients from things that they can’t digest by their own enzymes?
they use symbionts within the digestive tract
How can we distinguish endosymbionts?
whether they are in the lumen of the gut, or in tissues
What are enterosymbionts?
live in the gut and increases nutrient availability
What do animals that lack a digestive tract do get energy?
rely on endosymbiotic bacteria to convert organic chemical energy into useable forms, and these are found in their body tissues
Where are endosymbionts located?
the body tissues
How do Riftia (have no mouth, digestive tract, no anus) get their nutrients without eating?
have a bag of bacteria that they treat as a farm and use their red gills to harvest nutrients that they deliver to the bacteria, which converts them into carbon based nutrients, and use this instead of food
What is the symbiotic relationship between coral and microbes that are embedded in their tissues?
coral protects the protists, allowing the microbes to live and reproduce, and in exchange they take the nutrients the protists make through photosynthesis
How could an animal obtain chloroplasts?
from the food they eat, they can harvest the chloroplasts from them, and can even use them for photosynthesis. could cause the animal to become green coloured
What are the 2 most common non-digestible molecules eaten?
cellulose and chitin
What is cellulose, and how can some animals breakdown this molecule for nutrients, despite it being non-digestible for most animals?
-glucose polymer
-plants use it for structure
-animals lack cellulase enzyme needed to break it down
-some animals use enterosymbionts for breakdown (ex. fungi, protists, and bacteria that digest cellulose)
-ex. rabbits breakdown some of it, then eat their feces to try and break down more of it
What is chitin, and how can some animals breakdown this molecule for nutrients, despite it being non-digestible for most animals?
-frogs and whales eat lots of invertebrates, which means lots of chitin
-examples of species that have evolved enzymes that have been able to acquire a bit of the ability to break down chitin
What is the difference between animals being able to break down chitin vs cellulose?
Cellulase: taking on an enzyme dedicated to cellulose and stealing it from something else
Chitinase: taking one of their own glucose modifying enzymes and tweaking it
What are endosymbiotic microbes? And how would they have been acquired by some animals?
-have their own version of cellulase
-used by termites
-through horizontal gene transfer, these animals stole a microbes cellulase gene and incorporated it into its own genome
What can enterosymbionts be used to break down?
cellulose
Why is lysozomes secreted in humans?
to prevent bacteria from growing on the surface as part of the immune system.
How do lysozomes and entertosymbionts work together for animal digestion?
animals use enterosymbionts for the breakdown of cellulose, and lysozomes are used to break down the cell walls of the bacteria in the gut.
What is the function of tight junctions in the human gut?
prevent material from leaking between the gut between cells into the extracellular fluid
What is one response the body could have if the microbiome of the gut is out of balance?
can result in cellular damage (ex. cell to cell communication could be broken and bacteria could make its way across the body into the epithelium, and result in inflammation and more)
What could be a specialized region of the gut?
regions for digestion in acid vs base, and areas for specific nutrients
How do the simplest animals complete digestion?
blind sacs
