Brain and the nervous system 1

Question 1

What is the purpose of communication in organisms

Answer 1

to control functions an coordinate responses, like movement

Question 2

WHat does communication help regulate

Answer 2

Responses to conditions or sensory stimuli

Question 3

WHy is communication important for homeostasis

Answer 3

helps body maintain stable internal conditions

Question 4

do all multicellular organisms have communication systems

Answer 4

yesbut the complexity varies widely

Question 5

WHat do neurons do

Answer 5

capable of producing and transmitting action potentials

Question 6

what is an action potential

Answer 6

temporary change in voltage across a neurons membrane

Question 7

How does an action potential move

Answer 7

travels down neuron like mexican wave

Question 8

what is a soma

Answer 8

neuronal cell body
contains nucleus
site of protein synthesis

Question 9

Dendrites describe

Answer 9

many per neuron
receive incoming inputs from other neurons
converge on the soma

Question 10

Axon describe

Answer 10

carries action potential
axon terminal branches into many terminal boutons
insulated with myelin sheath

Question 11

WHat do synapses do

Answer 11

connect between neurons that transmit signals from one cell to next

Question 12

What direction does a nerve signal travel between two neurons

Answer 12

It goes in one direction
from the axon terminal of nerve 1 to the dendrite of nerve 2

Question 13

Names of cells sending and receiving signal

Answer 13

presynaptic sends
postsynaptic receives

Question 14

How do neurons connect with each other?

Answer 14

One axon can branch and connect to many dendrites, forming thousands of connections

Question 15

How many synapses are in the human brain

Answer 15

Around 100,000 billion (100 trillion)

Question 16

What does the soma (cell body) do

Answer 16

Integrates signals from all incoming dendrites

Question 17

What do dendrites do

Answer 17

receives impulses from other neurons

Question 18

What are dendrites covered with

Answer 18

axon terminals from other neurons

Question 19

Where are incoming signals integrated

Answer 19

cell body (soma)

Question 20

What does the cell body decide

Answer 20

whether or not to send a signal down the axon

Question 21

How do synapses communicate step by step

Answer 21

1) Action Pot travels down presynaptic cell
2) AP stimulates release of neurotransmitter across synapse
3) Neurotransmitter binds to receptors on postsynaptic cell
4) receptor binding triggers AP in postsynaptic cell
5) Impulse continues along postsynaptic cell

Question 22

What 3 ways are neurotransmitters removed from the synapse

Answer 22

1) taken back into presynaptic axon terminal for reuse or transported to nearby glial cells
2) Enzymes inactivate neurotransmitters by breaking them down
3) Diffuse out of synaptic cleft

Question 23

Whya re neurotransmitters removed from the synaptic cleft

Answer 23

keep CNS fast and efficient

Question 24

What is divergence in the nervous system

Answer 24

One presynaptic neuron connects to many postsynaptic neurons

Question 25

What is convergence in nervous system

Answer 25

Many presynaptic neurons connect to one postsynaptic neuron keeps signal specific

Question 26

when does divergence happen

Answer 26

when one neuron sends signals to multiple others (post to pre)

Question 27

When does convergence occur

Answer 27

when multiple neurons send signals to one neuron (pre to post)

Question 28

Why are divergence and convergence important

Answer 28

controls whether signals widely or tightly focused in cns

Question 29

what signal is specific and what signal is widely spread

Answer 29

Postsynapse to presynaptic = widely Presynaptic to postsynaptic = specific

Question 30

What are the different types of neuron

Answer 30

afferent neurons Efferent neurons Interneurons

Question 31

what do afferent neurons do

Answer 31

-carry info from periphery into CNS -convert sensory info into AP

Question 32

what do afferent neurons look like

Answer 32

Light bulb in middle

Question 33

What do efferent neurons do

Answer 33

Carry commands from CNS to effectors e.g. glands and muscles

Question 34

what do efferent neurons look like

Answer 34

normal

Question 35

what do interneurons do

Answer 35

-form connections and circuits between neurons -connect afferent and efferent -increase complexity of CNS -involved in storing info

Question 36

What do interneurons look like

Answer 36

doesnt have myelinated sxon short and fat

Question 37

three ways neurons have specialised

Answer 37

-Few dendrites -lots of dendrites -branched dendrites

Question 38

Fewer dendrites how do they benefit neurons

Answer 38

deal with fewer inputs deal with vision (neuron in retina) Limited amount of incoming info

Question 39

Lots of dendrites benefits

Answer 39

huge amount of inputs cerebellum neuron controls intricate complex movements

Question 40

branched dendrites benefits

Answer 40

long axon neuron in cortex wide and long distance communication

Question 41

reflexes purpose

Answer 41

Protect us by triggering quick responses to harmful situations

Question 42

What is the withdrawal reflex

Answer 42

A basic reflex that pulls the body away from danger

Question 43

What neurons are inolved in the withdrawal reflex

Answer 43

One afferent sensory one interneuron one efferent motor neuron

Question 44

Does the withdrawal reflex need the brain

Answer 44

no its processed only in spinal cord for speed

Question 45

What is the term for this fast spinal cord based reaction

Answer 45

a spinal ref;ex

Question 46

withdrawal reflex step by step

Answer 46

1) Heat activates skin receptors -> attached to afferent neurons 2) produces action potential in dendrites of these neurons 3) travel along afferent neuron into spinal cord 4) Activates dendrites of interneuon 5) AP relayed through interneuron -> efferent neuron 6) Impulse travels down axon of efferent neuron 7) Stimulates muscle contraction and arm moves 8) Finger removed from flame

Question 47

Describe the nerve net

Answer 47

Simplest network small numbers of connected neurons

Question 48

what is a group of neurons called

Answer 48

ganglia

Question 49

Describe the spinal cord

Answer 49

thickened cluster of nerve fibres connects distant parts of organism

Question 50

What type of nervous system do sea anemones have

Answer 50

simple nerve net

Question 51

what are nerve nets made of

Answer 51

long nerve projections with few connections NOT highly branched

Question 52

What do nerve nets allow the organism to do

Answer 52

perform simple responses like reflexes and basic movements

Question 53

GIve an example of a function controlled by a nerve net

Answer 53

contraction and relaxation of body parts

Question 54

How is the earthworms nervous system organised

Answer 54

it has segmented innervation with ganglia in each body segment

Question 55

What do segmental ganglia do

Answer 55

control movement within their segment via segremental nerves

Question 56

WHat is the role of anterior ganglia in earthworms

Answer 56

act like a brain coordinating complex behaviours

Question 57

Give an example of complex behaviour in earthworms

Answer 57

surfacing in response to rain sensory input leads to a motor response

Question 58

How is the squid’s nervous system more advanced than simpler animals

Answer 58

It has a specialised, organised pattern that allows complex behaviour and high-level integration

Question 59

What do specialised ganglia in squid do

Answer 59

Control specific functions through dedicated nerve pathways

Question 60

What is the role of the stellate ganglia in nerves in a squid

Answer 60

coordinate intricate and rapid movement patterns

Question 61

How are squid sensory systems adapted

Answer 61

Large visual ganglia controls vision

Question 62

what are the two components of animals nervous system

Answer 62

1) CNS = brain and spine, processing centre, encased in bone 2) Peripheral nervous system = info relay, communication system periphery and CNS communicate back and forth