Lecture 2

Question 1

How does an organism flexibly behave

Answer 1

1 - register ( sense environment )
2 - transform ( interpret - make sense of those signals )
3 - Generate appropriate response

Question 2

Behaviour

Answer 2

an organisms internally coordinated response as a result of changes in its internal or external environment

Question 3

Behaviour in simple organisms eg

Answer 3

plants ( although phototropism - growing plant follows path of sun )

Question 4

Behaviour in complex organisms eg.

Answer 4

animals
- Involves constant monitoring

Question 5

why does an animal need an NS?

Answer 5

to integrate the complex signals and select appropriate response from many options

Question 6

what happens in complex system

Answer 6

if a change is strong enough, it causes the signal to be transmitted down the chain of cells ( neural pathway )
–> this is a chain that feedsback on its self ( cycles of signal generation ) –> which will eventually reach some output system eg. Motor neurone leading to some behaviour

Question 7

cascade of cascades

Answer 7

communication of signals from one cell to the next as the cell changes its internal chemistry and as a result another cell changes its internal chemisty

Question 8

ADHD example

Answer 8

have to think about every little movement so not much left attention for other things

Question 9

register

Answer 9

sense info from environment
eg. magnetic fields - birds sense it and plan flight direction but humans cannot do that

Question 10

transformation

Answer 10

internal change ( coordinated response )
process change
eg. prick by needle, there is a mechanical change but if your under anaesthesia, you won’t recognise this change

Question 11

res

Question 12

Response

Answer 12

brains respond
no conscious thought
automatic

Question 13

difference between plant and animal ?

Answer 13

Animal can register more than just light, but also sound
animals can respond to complex stimuli eg. chainsaw and we can’t always predict their behaviour

Question 14

Only multicellular animal without NS

Answer 14

sponge

Question 15

Nervous system

Answer 15

network of electro-chemically active cells ( neurones) that are specialised to communicate with eachother

Question 16

direction of signal transfer

Answer 16

1 - strong enough chemical change
2 - signal
3 - change to active from inactive
etc.

Question 17

simplest form of NS

Answer 17

uncentralised
( hydra - sea star eg. ) - no nerve centre
every part is as important
evenly set our network of neurones condensed to ring an radial arms
cell body – axon – cell body – axon

Question 18

hydra - what does nerve centre control

Answer 18

activity of groups of other neurones
actions of distant body parts

Question 19

structurally centralised NS examples

Answer 19

flatworm
leech
insect
( with separate CNS ) - protobrain, nerve cord , PNS

nerve cords scattered around body
CNS - brain, nerve cord
PNS - all other neurones spread out

Question 20

NS of vertebrates ( animal with spine just like us ) structure

Answer 20

CNS + PNS more clearly separated

Question 21

NS vertebrates function

Answer 21

more hierarchy organised
brain - specialised to direct communication between neurones control actions of distant body parts
PNS more under control of CNS

Question 22

CNS

Answer 22

brain + spinal cord
encased in bones
brain - skull
spinal cord - vertebrates

Question 23

PNS - input from sense organs

Answer 23

somatic NS

Question 24

somatic NS

Answer 24

picks up info from environment ( 5 senses )
and produces output in muscles
voluntary control

Question 25

whats in input and output of somatic NS

Answer 25

input - senses
output - skeletal muscles
voluntary

Question 26

PNS - no external output

Answer 26

autonomic NS

Question 27

autonomic NS parts

Answer 27

1 - sympathetic part ( fight or flight ) - eg, exam - get sweaty hands
2 - parasympathetic part ( rest and maintenance ) eg. lying down

Question 28

autonomic NS

Answer 28

doesn’t have any external input
not directly connected to senses
only receives input from CNS

Question 29

output of Autonomic NS

Answer 29

muscles + glands
involuntary control ( eg movement of gut )

Question 30

Can we ‘behave’ without brain ?

Answer 30

we can detect, transform, motor command by 2 neurones in spinal cord ( so no brain )

Question 31

what are the links between PNS and CNS

Answer 31

sensory signals from body ( x head ) –> CNS
via spinal cord

Motor signals leave CNS via spinal cord

Question 32

white matter

Answer 32

myelinated axons of neurones

Question 33

grey matter

Answer 33

highly condensed neurones cell bodies
cortex + sub-cortical nuclei

Question 34

NS function

Answer 34

control + coordinate behaviour
so we can react
quickly
flexibly
high precision
in response to environment

Question 35

monosynaptic reflex arc example

Answer 35

knee jerk reflex
one connection

Question 36

monosynaptic reflex arc

Answer 36

specific receptors ( muscle spindles ) in muscle fibre
activate sensory neurone when stretched
axons go to spinal cord via dorsal root
dorsal root directly connects to motor neurone , which send their axons out via ventral root
same muscle activated from which signal originated
muscle contracts

Question 37

why do we need monosynaptic refelxes

Answer 37

to ‘resist’ and ‘dampen’ quick stretching of skeletal muscles, enabling smooth, stable movement

Question 38

can monosynaptic reflex arcs have more than one synaptic connection ?

Answer 38

yes. BUT
only 1 connection between sensory and motor neurone

the other connection may be where the sensory or motor neurone receives the input from

Question 39

polysynaptic reflex arc

Answer 39

sensory and motor connected by 1+ interneurones

receptor end of sensory enurone + effector end - diff places
( withdrawal reflex )

more flexible arrangement can sometimes show simple forms of learning - eg. aplysia

Question 40

synapse

Answer 40

signalling link between neurone and another cell / neurone

Question 42

synapse structure

Answer 42

specialised sender part of neurone is close to specialised recipient part of target cell

2 neurones have many synapses

many contact points - but all for same signal

Question 43

function of synapse - monosynaptic

Answer 43

one synapse linking sensory and motor neurone

Question 44

function synapse - polysynaptic

Answer 44

many synapses between sensory and motor
bi-synaptic - 2
try-synaptic - 3
polysynaptic - many

Question 45

central pattern generators

Answer 45

spinal cord neurones can generate complex movement patterns - in response to appropriate stimulation

cannot voluntarily initiate movements eg ‘ I want to walk’

Question 46

example of central pattern generators

Answer 46

cat with spinal cord resection walking on treadmill

Question 47

cat spinal cord explanation

Answer 47

cat accident - spinal cord cut
initial signal arriving from hind legs cannot be sent to brain so that signal has no effect as motor neurone isn’t aware of the signal

on treadmill..
provide support + keep body upright
set in motion ( moving stimulus below feet )
cat feet move in coordinated stepping pattern
- must happen locally in spinal cord as connection with brain is severed