Biopsychology: Divisions of the nervous system

The Nervous System- Macro Level

• highly specialised set of cells in the human body

• primary internal communication system

• made up of billions of neurons

• brain is described as the most complicated structure in the universe

The nervous system diagram

Peripheral nervous system (somantic and autonomic systems with autonomic leading to sympathetic and para-sympathetic branch)

Central nervous system (brain and spinal cord)

Central nervous system- Brain

• involved in all psychological processes and ensures life is maintained

• some parts are more primitive involving vital functioning (breathing and heartbeat)

• other areas have high order thinking such as planning and problem solving

• has 2 main functions; 1) collect, process and respond to information. 2) coordinate and direct the working of different organs and cells within the body

Central nervous system- Spinal cord

• carries messages (using neurons) to and from the brain to the peripheral nervous system

• relays information to and from the brain and the rest of the body

• allows brain to monitor bodily processes like breathing and digestion and co-ordinate all bodily movements

• main centre for reflex actions

arc reflex

• special type of neural circuit that begins with a sensory neuron at a receptor and ends with a motor neuron and an effector

• receptor in the skin detects a stimulus and sensory neuron sends electrical impulses to the relay neuron located in the spinal cord

• motor neuron sends electrical impulse to an effector

• effector produces a response

Peripheral Nervous System

• all the nerves outside of the brain and the spinal cord

• It’s main function is to relay nerve impulses from the CNS to the rest of the body and back to the CNS

• 12 pairs of cranial nerves and 31 pairs of spinal nerves

• lots of sensory and motor pathways allow the CNS to be aware of what’s going on in the body and the outside body

• This allows the CNS to control our various responses

• has two main parts: somatic nervous system and the autonomic nervous system

The Somatic Nervous System

• maintains communication between the CNS and outside world

• Sensory receptors: Carry info to the spinal cord and brain, sensory pathways transmit and receive info from the senses

• Motor pathways: allow the brain to control movement, motor pathways create direct voluntary movement of the skeletal muscles due to the brain

• Control centre= Brain (motor & somatosensory cortex): made up of 12 pairs of cranial nerves and 31 pairs of spinal nerves, connects the CNS to our senses, contains both sensory and motor neurons

The Autonomic Nervous System (ANS)

• responsible for functions that keep the body in a stable state (homeostasis)

• many functions are automatic

• Control centre= Top of brain stem (hypothalamus and pituitary gland)

comparing the Peripheral nervous systems

1. The autonomic system is involuntary whereas the somatic nervous system under conscious control

2. The SNS has both sensory and motor neurons whereas the ANS uses only motor neurons

3. The ANS controls internal organs/ glands of the body whereas the SNS controls skeletal muscle and movement

4. The control centre for the SNS is located in the motor and somatosensory cortex whereas the control centre for the ANS is located in the brain stem (pituitary gland/ hypothalamus)