Module 5- Homeostasis Flashcards
what is Homeostasis?
maintaining a constant internal environment despite changes to the external environment
why is Homeostasis important?
-to ensure enzymes function
-to control energy
-to control the movement of molecules
what are negative feedback systems?
-they work to reverse the initial stimulus
-a small change is detected by sensory receptors leading to effectors reversing the change and restore conditions
what are some examples of negative feedback?
temperature control, blood glucose
what are positive feedback systems?
they enhance the effect of the original stimulus
what is an ectotherm?
-use their surroundings e.g. the sun to warm their bodies
-core body temperature is heavily dependent on their environment
how do ectotherms control their body temperature (behavioral)?
-display behaviours to increase/decrease the radiation they absorb from the sun e.g. basking
-through conduction e.g. pressing body against cold/hot surface
-seeking shade in high temperatures
what is basking?
when an animal orientates or extends its body so that the maximum surface area is exposed to the sun e.g. chameleons
what is excretion?
the removal of the waste products of metabolism from the body
why do metabolic wastes need to be removed?
they are toxic if allowed to build up
what are the main metabolic waste products in animals?
carbon dioxide, bile pigments, nitrogenous waste products (urea)
what is another name for a liver cell?
hepatocyte
what indicates hepatocytes are very metabolically active?
they have lots of mitochondria
how is oxygenated blood supplied to the liver?
hepatic portal vein
what are the functions of the liver?
storage of glycogen
formation of urea
detoxification
