Homeostasis Flashcards
what is homeostasis
the condition of a relatively stable internal environment, maintained within narrow limits and when deviations occur in the internal environment, a healthy organism restores inteslf to the normal state
what two systems coordinate all the functions of the body
the endocrine system and the nervous system
what does the nervous system include
the brain and spinal cord - central nervous system (CNS), nerves - peripheral nervous system (PNS)
what does the endocrine system include
glands and organs that produce hormones - adrenal glands, thyroid glands, pituitary glands, hypothalamus and pancreas
what does the hypothalamus control
body temp
what does the pituitary glands control
growth hormones and water balance
how is a response from hormones issued
hormones are chemicals that are transported in the blood stream where hormonal responses take much longer to show effect but last longer
how is a response from a nerve issued
nerves use chemicals called neurotransmitters to facilitate electrical signalling, bring a response rapidly that doeesn’t usually last lonng
how are homeostatic responses initiated
external or internal stimulus which is detected by a specific type of receptor
what is homeostasis responsible for maintaining
blood pressure, ph levels, water levels, salt levels, blood carbon dioxide and oxygen concentration
what is a stimulus response model
when the body detects a change from the stable state of ph levels, salt levels, etc (increase or decrease) the changes are contracted by responses in the body
what are the parts of the stimulus response model
stimulus, receptors, control center/modulator, effectors, response
what is a stimulus
a change in the external or internal environment of an organism
what is a receptor
where the stimulus is detected and transfered into a chemical/electrical signal for transmission to the modulator
what are examples of a receptor
cell receptors - proteins embedded in the membrane or cytosol or an entire cell
