Biopsychology
The nervous system (NS)
Human nervous system = a complex of nerve cells that carries
messages to and from the brain and spinal cord.
The central nervous system:
- Spinal cord relays info between brain & rest of body; allowing the brain to
regulate & monitor bodily processes. The spinal cord is connected to various
parts of the body by pairs of spinal nerves.
- Spinal cord also contains circuit of nerve cells that enable us to perform some
simple tasks without direct involvement of the brain (e.g. pulling hand away
from hot surface) = reflex arc; nerve pathway with motor & sensory nerve with
synapse in between.
The brain is divided into 4 areas: Cerebrum
- Cerebrum
- Cerebellum
- Diencephalon
- Brain stem
Diencephalon
Cerebellum
Brain stem
Cerebrum = largest part of brain and divided into 4 different lobes that each have a
primary function. The cerebrum is split down the middle into 2 cerebral hemispheres.
, The peripheral nervous system:
à made up of 2 systems; somatic & autonomic nervous system
Somatic nervous system
- Responsible for carrying sensory info to and from the CNS
- It involves voluntary actions
- It is 12 pairs of cranial nerves & 31 pairs of spinal nerves, they’re both sensory &
motor neurons – the sensory neurons relay messages to the CNS & the motor
neurons relay info from the CNS to other parts of the body.
Autonomic nervous system
- Involved with actions that aren’t consciously performed (automatic) e.g.
heartbeat
- Made up of 2 parts; sympathetic & parasympathetic which both regulate
organs but have opposite effects.
Sympathetic nervous system Parasympathetic nervous system
à uses the neurotransmitter noradrenaline à uses Acetylcholine & this has
which has stimulating effects & helps in an inhibitory effect, it restores the
times of crisis, such as the stress response, body to normal – lowers heart
increased heart rate/oxygen flow – flight or rate/restarts digestion.
fight.
Neurons and synaptic transmission
The nervous system
carries messages from 1
part of body to another
using nerve cells called
neurons. They transmit
messages in the form of
short
electrical impulses. short dendrites &
dendrites
short axon
& long
Long dendrites & axon
3 types of neurons; short axon
, Sensory – tell rest of Relay – carry Motor – carry signals
brain about internal & messages from 1 part from CNS to help
external environment of CNS to another. organs, includes
by processing info They connect motor glands and muscle
taken from the 5 & sensory. functions.
senses.
- Neuron cells come in many shapes/sizes depending on where they are in
body. They’re covered in a complex cell membrane of several layers that
allows the neuron to conduct/transmit electric activity (=action potentials or
nerve impulses).
- In humans & other mammals, the neurons in the NS are covered in myelin
sheath (=insulating layer that allows impulse to travel quickly/efficiently along
the nerve cell).
- The gaps are known as nodes of Ranvier (=where the cell body is exposed)
They allow for action potential to quickly travel down the axon. Without these
breaks of myelin sheath, the action potential wouldn’t travel as quickly.
Synapses;
Neurons aren’t physically connected to each other – there’s a small gap between
axon terminal & the next neuron’s dendrites called the synaptic gap/cleft.
Info is passed down the axon of the neuron as an electrical impulse known as action
potential.
Once the AP reaches the end of axon, it needs to be transferred to another
neuron/tissue. At the end of the neuron (in axon terminal) there’re synaptic vesicles
which contain chemical messages known as neurotransmitters. When the AP
reaches these synaptic vesicles, they release their contents of neurotransmitters.
Neurotransmitters then carry the signal across the synaptic gap. They bind to specific
receptor sites on post-synaptic neuron that then become activated.
The nervous system (NS)
Human nervous system = a complex of nerve cells that carries
messages to and from the brain and spinal cord.
The central nervous system:
- Spinal cord relays info between brain & rest of body; allowing the brain to
regulate & monitor bodily processes. The spinal cord is connected to various
parts of the body by pairs of spinal nerves.
- Spinal cord also contains circuit of nerve cells that enable us to perform some
simple tasks without direct involvement of the brain (e.g. pulling hand away
from hot surface) = reflex arc; nerve pathway with motor & sensory nerve with
synapse in between.
The brain is divided into 4 areas: Cerebrum
- Cerebrum
- Cerebellum
- Diencephalon
- Brain stem
Diencephalon
Cerebellum
Brain stem
Cerebrum = largest part of brain and divided into 4 different lobes that each have a
primary function. The cerebrum is split down the middle into 2 cerebral hemispheres.
, The peripheral nervous system:
à made up of 2 systems; somatic & autonomic nervous system
Somatic nervous system
- Responsible for carrying sensory info to and from the CNS
- It involves voluntary actions
- It is 12 pairs of cranial nerves & 31 pairs of spinal nerves, they’re both sensory &
motor neurons – the sensory neurons relay messages to the CNS & the motor
neurons relay info from the CNS to other parts of the body.
Autonomic nervous system
- Involved with actions that aren’t consciously performed (automatic) e.g.
heartbeat
- Made up of 2 parts; sympathetic & parasympathetic which both regulate
organs but have opposite effects.
Sympathetic nervous system Parasympathetic nervous system
à uses the neurotransmitter noradrenaline à uses Acetylcholine & this has
which has stimulating effects & helps in an inhibitory effect, it restores the
times of crisis, such as the stress response, body to normal – lowers heart
increased heart rate/oxygen flow – flight or rate/restarts digestion.
fight.
Neurons and synaptic transmission
The nervous system
carries messages from 1
part of body to another
using nerve cells called
neurons. They transmit
messages in the form of
short
electrical impulses. short dendrites &
dendrites
short axon
& long
Long dendrites & axon
3 types of neurons; short axon
, Sensory – tell rest of Relay – carry Motor – carry signals
brain about internal & messages from 1 part from CNS to help
external environment of CNS to another. organs, includes
by processing info They connect motor glands and muscle
taken from the 5 & sensory. functions.
senses.
- Neuron cells come in many shapes/sizes depending on where they are in
body. They’re covered in a complex cell membrane of several layers that
allows the neuron to conduct/transmit electric activity (=action potentials or
nerve impulses).
- In humans & other mammals, the neurons in the NS are covered in myelin
sheath (=insulating layer that allows impulse to travel quickly/efficiently along
the nerve cell).
- The gaps are known as nodes of Ranvier (=where the cell body is exposed)
They allow for action potential to quickly travel down the axon. Without these
breaks of myelin sheath, the action potential wouldn’t travel as quickly.
Synapses;
Neurons aren’t physically connected to each other – there’s a small gap between
axon terminal & the next neuron’s dendrites called the synaptic gap/cleft.
Info is passed down the axon of the neuron as an electrical impulse known as action
potential.
Once the AP reaches the end of axon, it needs to be transferred to another
neuron/tissue. At the end of the neuron (in axon terminal) there’re synaptic vesicles
which contain chemical messages known as neurotransmitters. When the AP
reaches these synaptic vesicles, they release their contents of neurotransmitters.
Neurotransmitters then carry the signal across the synaptic gap. They bind to specific
receptor sites on post-synaptic neuron that then become activated.
