coordination and response Flashcards
electrical impulses are carried by
neurones
two parts of mammalian nervous system + description
- central n.s (CNS): brain + spinal cord
- peripheral n.s (PNS): network of nerves that lie outside CNS
role of nervous system
coordination + regulation of bodily functions
sensory neurone
sense organ to CNS
relay neurone
make connection between sensory and motor in CNS
motor neurone
CNS to effector organ
reflex arc
path travelled by impulse to bring action
- stimuli detected by receptors
- carried as impulse from sensory to relay in CNS
- to motor across another synapse
- motor transmits to effector organ
- response occurs
reflex action
automated response to a stimulus
synapse
junction between two neurons
synapse vesicles hold
neurotransmitters
neurotransmitters bind to
receptor proteins
events at synapse
- impulse triggers vesicles to fuse with presynaptic membrane
- vesicles release neurotransmitters into gap
- n.t diffuse bind to complementary receptor proteins on postsynaptic membrane
- impulse triggered on post.s neurone
- n.t broken down by enzymes
- mitochondria provides energy to reform them
sense organ
group of receptor cells responding to a specific stimuli
cornea
refracts light
iris
controls how much light enters
lens
focuses light on retina
retina
light sensitive layer w. receptor cells
optic nerve
carry impulse to brain
pupil in bright light + muscles involved
- circular muscles contracts
- radial muscles relax
- constricts
pupil in dim light + muscles involved
- circular muscles relax
- radial muscles contract
- dilates
viewing distant objects
- suspensory ligaments contracts
- ciliary muscles relax
- lens gets thinner
- less refraction
viewing near objects
- suspensory ligaments relax
- ciliary muscles contract
- lens gets fatter
- more refraction
rods
- night vision
- light sensitive
cones
- color vision (RGB)
- more than rods at fovea
- sharper image
blind spot
no rods or cones
hormone
chemical substance produced by endocrine glands + carried by blood + alter the activity of one or more target organs
adrenal glands
adrenaline
pancreas
insulin + glucagon
ovary
estrogen
testes
testosterone
adrenaline is
secreted during “fight or flight” situations
effects of adrenaline during fight or flight
increased:
- breathing rate
- heart rate
- pupils dilate
adrenaline can also increase
- blood glucose con.
- heart rate
differences of nervous and hormonal
- hormonal has lasting effect, nervous has short-lived
- hormonal has delayed response, nervous has quick response
homeostasis
maintenance of a constant internal environment
insulin function
decrease blood glucose con.
negative feedback is
keeping in range, control kuranee
when blood glucose high
insulin brings level back to normal, influences:
- glucose converted in liver to glycogen
when blood glucose low
glucagon brings level back to normal, influences:
- stored glycogen converted to glucose and released into blood
treatment of type 1 diabetes
regular insulin injections
overheating
- vasodilation
- sweating
- erector muscles relax
overcooling
- vasoconstriction
- shivering
- erector muscles contract
- reduced sweating
vasoconstriction
- blood vessels (arteroles) in dermis constrict
- less warm blood flows near surface (capillaries)
- less heat lost by conduction + convection + radiation
sweating
sweat evaporates taking latent heat so body cools
erector muscles relax
hairs lie flat and can’t trap air layer so heat lost
shivering
contractions in muscles and limbs generate heat
erector muscles contract
hair stands upright trapping layer of air which is bad conductor
gravitropism
response where plants grow toward / away from gravity
phototropism
response where plants grow toward / away from direction from which light is coming
auxin in phototropism
- made in tip of the shoot
- accumulates on dark side
- stimulates cell growth on dark side so grows faster
- tip points toward light
auxin gravitropism
- made in tip of the root
- accumulates on horizontal lower
- slows cell growth on that side
- tip points toward gravity
