Homeostasis p2 Flashcards
(39 cards)
why do our bodies do homeostasis
because our enzymes and cells require very stable conditions to work
-can’t work well if conditions around them change
define homeostasis
the regulation of internal conditions in response to internal snd external changes, to constantly maintain optimum conditions for functioning
what 3 things does homeostasis regulate
-blood glucose concentration
-body temperature
-water levels
what 2 types of responses do automatic control systems involve
nervous
chemical
all control systems involve: (3 things)
- RECEPTOR CELLS hich detect a stimuli
- COORDINATION CENTRES which receive and process information from receptors
3.EFFECTORS which produce rrsponses to restore optimum conditions
give 3 examples of coordination centres
brain, spinal cord, pancreas
define stimulus
a change in the environment
give 2 examples of effectors
muscles
glands
what 2 parts make up the nervous system
CNS (central nervous system) and a network of nerves
what makes up the CNS
brain & spinal cord
function of nervous stystem
enables humans to react to their surroundings and to coordinate their behavious - this inkudes voluntary and involuntary actions
normal nervous system response
stimulus
-(detected by)
receptors
-(sends signal along neurones to)
coordinator
effector
response
define reflex action
automatic and rapid as they do not involve conscious part of brain
important for survival as they help prevent damage to the body
reflex arc
receptor cells detect a stimulus
impulse sent across sensory neurone
diffuses across synapse to relay neurone
diffuses across synapse to motor neurone
impulse triggers effector
to produce a response
describe adaptations of neurones
DENDRITES
-branched endings on cell body which allow connections sith other neurones or effectors
MYELIN SHEATH
-insulates the axon, increasing speed of electrical impulses
describe how impulses pass between neurones
there are gaps between neurones called synapss
-chemicals are released in between gap and then trigger an electrical impulse across next neurone
define the brain
organ which controls complex behaviour
-made of billions of imterconnected neurones, with different regions that carry out different functions
name and function of highly folded outer part of brain
cerebral cortex
FUNCTION: language, memory, consciousness
where is cerebellum and what does it do
leafy part of the brain
FUNCTION: controls balance and muscle activity
whats the part of the brain above the spinal cord called
function?
medulla
(controls unconscious activities)
-controls heart rate and breathing rate
why is it difficult to study the brain and treat brain disorders
-protected by skull (tricky to access)
-structures of brain are extremely complex (difficult to work out which parts of the brain carry out specific functions)
-extremely delicate, easy to damage
which methods have been used to research the brain
MRI scanning techniques
electrically stimulating parts of the brain
why is treatment of the brain difficult (3 things)
-not fully understood what each area of the brain does
-drugs do not always reach the brain through its membranes
-surgery can easily cause unintended damage
whats the system called which regulates body temperature
thermoregulatory system
