Biopsychology - Nervous System Flashcards
What is the central nervous system?
The central nervous system
- consists of brain and spinal cord
- receives information from the senses
- regulates the body’s psychological processes.
Role of the spinal cord
The role of the spinal cord is to transfer messages to and from the brain, and the rest of the body.
The spinal cord is also responsible for simple reflex actions that do not involve the brain, for example jumping out of your chair if you sit on a drawing pin.
Describe how the fight or flight response is triggered
The endocrine system and the ANS often work together.
For example, when a person perceives a situation as stressful, the sympathetic branch of the ANS is triggered.
The stress hormone adrenaline is released in response, leading to physiological changes (increased heart rate, sweating, and so on- the ‘fight or flight’ response). This state of arousal in the system is known as the ‘sympathetic’ state.
Once the perceived stressor passes, the ‘parasympathetic’ branch of the ANS returns the body to normal, reducing the effects and activity of the sympathetic branch.
What do motor neurons do?
Motor: Connect the central nervous system to muscles and glands
What do sensory neurons do?
Sensory: Carry messages from the PNS to the CNS
What do relay neurons do?
Relay: Connect sensory neurons to motor and other relay neurons
Describe the structure of neurons
- They have a cell body (soma), containing genetic material, and branches (dendrites) which carry nerve impulses to the soma.
- The axon carries impulses away from the soma. The axon is covered in a protective layer known as the myelin sheath, which speeds up transmission. This effect is achieved by making the impulse ‘jump’ between gaps in the myelin sheath- these gaps are known as the nodes of Ranvier.
- At the end of the neuron are terminal buttons which allow for communication with adjacent neurons- the gap between them is called the synapse.
What different effects can neurotransmitters have on the post-synaptic cell?
They have different effects, either excitation (increasing the post-synaptic neuron’s positive charge and the likelihood of the message being passed on) or inhibition (increasing the post-synaptic neuron’s negative charge and decreasing the likelihood of the message being passed on). For example, serotonin has an inhibitory effect, and adrenaline an excitatory effect.
How do SSRIs work?
Selective Serotonin Reuptake Inhibitors (SSRIs) work to increase the activity of serotonin, helping sufferers of obsessive-compulsive disorder relieve their symptoms.
What is the role of the peripheral nervous system?
Responsible for transmitting messages to and from the CNS through neurons (nerve cells).
What are the subdivisions of the PNS?
- Somatic nervous system
- Autonomic nervous system
What is the role of the somatic nervous system?
- Controls skeletal muscles for movement.
- Voluntary system (under conscious control)
What is the role of the autonomic nervous system?
- Controls actions of internal organs and glands.
- Involuntary system (not under conscious control)
What are the subdivisions of the ANS?
- Sympathetic branch
- Parasympathetic branch
What is the role of the sympathetic branch of the ANS?
- Increases bodily activities
- Releases noradrenaline
- Activates in stress response (fight or flight) e.g. increases heart rate, dilates pupils, inhibits digestion
