Nervous System Flashcards
1
Q
Central nervous system
A
- transmits motor info to PNS
- receives and processes sensory info from internal and external environment
- consists of motor neurons and interneurons
2
Q
Brain (CNS)
A
- processes sensory information and coordinates response
- involved in: decision making, learning, feeling, memory
3
Q
Sensory neurons
A
- afferent
- receives sensory information
- transmits info to CNS
- receptors
4
Q
Neural transmission
A
4
Q
Motor neurons
A
- efferent
- effectors
- transmits messages from CNS to organs, muscles, glands
4
Q
Interneurons
A
- only in CNS
- links sensory neurons with CNS then to motor neurons
5
Q
How the neuron receives messages
A
- dendrite receives info in form of a chemical message (neurochemical)
- soma sends a message in form of electrical signal
- electrical signal travels down axon
- when signal reaches axon terminals, triggers release of neurochemical
- terminal buttons release neurochemical
6
Q
Spinal cord (CNS)
A
long thin bundle of nerve fibres from base of brain to lower back
- ascending tracts transmit sensory info to brain
- descending tracts transmit motor info from brain to organs, muscles, glands
7
Q
Peripheral NS
A
network of neurons located outside of CNS
- consists of sensory and motor neurons
- carries info from sensory organs and internal organs to CNS
- transmits info from CNS to organs, muscles, glands
8
Q
Somatic NS (PNS)
A
- voluntary movement of skeletal muscles
- transmits sensory info from sensory receptors to CNS
- conscious control
SNS detects sensation and coordinates response ie. picking up cat when he rubs against your leg
9
Q
Autonomic NS (PNS)
A
- regulates activity of organs, visceral muscles, glands
- no conscious control
ie. heart rate, breathing
10
Q
Sympathetic NS (ANS)
A
- activates internal muscles, organs and glands to prepare body for vigorous activity or to deal with stress/ threatened
- fight, flight response
- arouses/ energises body
- enhances survival
11
Q
Physiological responses of sympathetic NS
A
- pupils dilate
- increased heart rate and breathing
- slows digestion
- relaxes bladder
- salivary glands inhibit
12
Q
Parasympathetic NS (ANS)
A
- counterbalances effect of SNS
- maintains homeostasis
- more dominant
- calms body and conserves energy
- freeze response
13
Q
Physiological responses of parasympathetic NS
A
- pupils constrict
- heart rate and breathing slows
- digestion stimulates
- salivary glands stimulate
14
Q
Conscious responses
A
- communication between brain and somatic NS
- goal directed
- awareness
- voluntary
- controlled
15
Q
Neural communication (conscious response)
A
- sensory receptors in (ie. skin) receive sensory info from (ie. fly on arm)
- sensory info transmitted along sensory neurons to brain
- brain receives and processes sensory info about (ie. fly) and initiates a motor response
- motor message transmitted along motor neurons to effector sites (ie. muscles in arm allowing her to brush fly off her arm)
16
Q
Neural communication (unconscious response/ spinal reflex)
A
- sensory receptors in (ie. hand) receive info about pressure and pain from (ie. nail)
- sensory info transmitted along sensory neurons to spinal cord
- info transferred to interneurons which initiate a response/ reflex
- motor message transmitted along motor neurons to effector sites (ie. muscles in arm allowing her to pull her hand away)
- sensory message travels to brain to enable interpretation of stimulus
17
Q
Unconscious response
A
- autonomic NS
- spinal reflex (SNS)
- involuntary/ automatic
- no awareness
- no conscious control
- increase chance of survival
- occurs in same way each time
ie. heart rate, breathing
18
Q
Spinal reflex/ reflex arc
A
unconscious, involuntary, automatic response to sensory stimuli that does not involve the brain
19
Q
Dendrites
A
detects and receives info from other neurons
20
Q
Soma
A
info passed on from dendrites, integrates info
21
Q
Axon
A
transmits neural info to other neurons
22
Q
Axon terminals
A
small branches at end of axon
23
Axon buttons
buttons at end of axon terminals, store and secrete neurochemicals that carry chemical messages to other neurons
24
Myelin sheath
white fatty substance around axon that insulates, protects and allows for rapid movement of messages along axon
25
What triggers the spinal reflex?
- danger
- threat
- harm
26
Advantages of spinal reflex
- faster response time
- less pain/ damage
- saves energy
27
Neurotransmitters
- affects one or two post-synaptic neurons
- inhibitory or excitatory
- faster acting
- not long lasting
- released into synapse
ie. GABA, Glutamate
28
Neuromodulators
- affects multiple post-synaptic neurons
- slower acting
- longer lasting
- can increase the excitatory or inhibitory effects of neurotransmitters
- released into tissue
ie. Dopamine, Serotonin
29
Glutamate
more likely to cause a neuron to fire and stimulate a response (excitatory neurotransmitter)
role in:
- cognition
- memory formation
- learning
30
GABA
more likely to stop a neuron from firing and calm neural activity (inhibitory neurotransmitter)
role in:
- motor control
- vision
decreasing anxiety
31
Dopamine roles
Roles:
- smooth muscle control, pleasure, attention, mood, learning/ motivation
Reward-based pathway (thirst/ hunger)
- when hungry you eat, alleviates hunger
Addiction
- addiction behaviour initially has an increase in dopamine that makes them feel pleasure
- causes then to increase behaviour but less dopamine is released
32
Serotonin roles
Mood
- low levels of serotonin impact ability to regulate mood
Sleep
- low levels of serotonin result in frequent awakenings during sleep
Impulsivity
- aggression -> low levels and difficulty controlling emotions
- impulsivity -> high levels of serotonin, people can delay the need to reward
33
Neural transmission process
1. neurochemicals released from vesicles of presynaptic neuron into synaptic gap
2. if complementary the neurochemicals bind to receptor sites on dendrites of post-synaptic neuron
3. neurochemicals can have an excitatory or inhibitory effect (increase or decrease chance of post-synpatic neuron firing)
34
Plasticity
brain's ability to re-organise and relocate neural pathways based on new experiences and learning
35
Sprouting (learning)
ability for dendrites or axons to develop new branches
36
Rerouting (re-learning)
neuron initially connected to damaged neuron, creates an alternative connection with an undamaged neuron
- establish a new neural pathway
37
Pruning (forgetting)
elimination of synaptic connections that are not adequately stimulated
- makes room for new connections
38
Long- term potentiation
strengthening of the connections between neurons as they are repeatedly coactivated
- strengthens neural pathway
- increase in receptor sites and neurotransmitters
39
Long-term depression
repeated low intensity stimulation of the post-synaptic neuron
- weaken neural pathway
- decrease in receptor sites and synaptic connections
