module 5 (2) Flashcards
(20 cards)
what’s an adaptation of the synaptic knob
has lots of mito and ER to make neurotransmitters
what do excitatory and inhibitory neurons do
excitatory = depolarisation
inhibitory = hyperpolarisation
what happens to neurotransmitters in the synapse
broken down by enzymes
products taken back to presynaptic knob
allows neurotransmitter recycled
prevents respond from happening again
why are synapses important
ensures synapses are unidirectional
(neurot. receptors only on post-synaptic membrane)
allows impulse from one neuron to be transmitted to multiple
neurons can feed into the same synapse
define summation
if the amount of neurotransmitters build up sufficiently to reach threshold then it triggers AP
define spatial summation
neurons connect to one synapse
define temporal summation
single neuron releases neurot as a result of high-frequent AP
which nervous system has shorter pre-ganglionic nerves
sympathetic
why do we have a central control centre
communication between neurons is much faster than if they were distributed around the body
how many centres does the hypothalamus have
1 parasymp, 1 symp
what is the role of the hypothalamus
controlling complex patterns of behaviour
monitoring composition of blood plasma
producing hormones
what are the divisions of the pituitary gland
anterior - produces 6 hormones (FSH)
posterior - stores and releases hormones produced by hypothalamus
what is the spinal cord
column of nervous tissue running up back
describe the knee-jerk reflex
leg tapped below patella
stretches patellar tendon (stimulus)
extensor muscle (on top of thigh) contract
flexor muscle relaxes (relay inhibits motor)
kick leg
what is the use of the knee-jerk reflex
maintain posture and balance
why is ATP required in muscle contraction
move myosin heads
for SR to actively reabsorb calcium ion
what happens to oxygen levels in active muscle
oxygen is used up more quickly than the blood supply can replace it
what does creatine phosphate act as
reserve supply of phosphate
stored in muscle cells
what does the thyroid gland produce
thyroxine
controls rate of metabolism
what does the thymus gland produce
thymosin
promotes production and maturation of WBC
