1. Division of the nervous system

2 main divisions of the nervous system

• Central nervous system (CNS)

• Peripheral nervous system (PNS)

main functions of the CNS

• processes, interprets + stores information

• issues orders to muscles, glands and organs

2 components of the CNS

• brain

• spinal chord

main functions of the brain

• cognition (conscious awareness)

• emotion

• sensory

• motor/movement

• e.g. perception, attention, memory etc.

main functions of the spinal chord

• bridge between brain and peripheral nerves (body)

• reflex actions

Structure of the brain

• Cerebral cortex- The brain's outer layer, most highly developed in humans, grey matter with many folds. Involved in a variety of higher cognitive, emotional, sensory and motor functions.

• Brain hemispheres- divides into 2 symmetrical hemispheres: left: languages, rational- analytical thinking and logical abilities, right: musical and artistic abilities

• Brain stem- connects the brain and spinal chord, as well as controlling involuntary processes e.g. breathing.- vital functioning and instinctive behaviour

structure of the spinal chord

white bundle of nerves which runs from the brain along a canal in the backbone. Roughly 40cm long and as wide as a thumb.

main functions of PNS

transmits information to and from CNS

2 components of PNS

• somatic nervous system

• autonomic nervous system

functions of somantic nervous system

• controls voluntary movements of skeletal muscles (e.g moving arm)

• maintains communication between CNS and outside world

• nerves carry messages from eyes, ears, skeletal muscles and skin to give CNS experience of environment

• posture and movement

SNS consists of…

• sensory receptors- carries info to spinal chord and brain

• motor pathways- allows brain to control movement

functions of autonomic nervous system

• regulates glands, blood vessels and internal organs

• plays an important role in homeostasis (maintains internal processes) e.g. secretion and metabolism

• controls involuntary movement from non-skeletal muscles (e.g. the ‘smooth muscels’ that control intestines, digestion, bladder, heart etc.)

• only consists of motor pathways

2 components of ANS

• sympathetic nervous system

• parasympathetic nervous system

Functions of sympathetic nervous system

• mobilises body for action- prepares body for fight or flight (e.g. increases heart rate and blood pressure)- activated in situations requiring arousal and energy e.g. when threatened/under stress

• energy output

Functions of parasympathetic nervous system

• conserves energy

• maintains quiet state

• returns body to normal resting state/homeostasis (e.g heart and respiratory rate return to normal level, blood pressure decreases)- activated soon after threat of danger has passed

Outline the structure and function of the nervous system (6 marks)

Bio-psychologists assume that thought and behaviour are caused by the activity in the nervous system. The nervous system is a specialised network of cells in the human body and is our primary internal communication system. The nervous system’s two main function are:

• collect, process and respond to information in the environment

• co-ordiante the working of different organs and cells

The central nervous system (CNS) is made up of the brain and spinal chord. The brain is the centre of all conscious awareness. The brain’s outer layer, the cerebral cortex, is highly developed in humans. The brain is divided in two hemispheres. The spinal chord is an extension of the brain. It is responsible for reflex actions. The PNS transmits messages via millions of nerurons (nerve cells), to and from the nervous system. The PNS is further sub-divided into:

• the somatic nervous system (SNS)

• the autonomic nervous system (ANS)

The SNS is the part of the PNS that is responsible for carrying sensory and motor information to and from the spinal chord. The autonomic nervous system governs vital functions in the body, such as breathing, digestion, heart rate, sexual arousal and stress responses.