VCE Psychology Unit 3 DP – the interaction between cognitive processes of the brain and its structure - Roles of the central nervous system, peripheral nervous system (somatic & autonomic) and autonomic nervous system (sympathetic & parasympathetic).

Overview of the Nervous system

Divisions of the nervous system The nervous system is divided into: Peripheral nervous system (PNS) Central nervous system (CNS) The CNS consists of: Brain Spinal cord

Chapter 4 of text book – The central nervous system Page 177 onwards

The role of the central nervous system Integrate and coordinate all incoming neural information Initiate messages sent to different parts of the body

Amazing brain facts Your skin weighs twice as much as your brain. Your brain uses 20% of total oxygen pumping around your body. 750ml of blood pumps through your brain every minute It consists of 100 billion neurons. Time until unconsciousness after loss of blood supply to brain is 8 – 10 seconds Approximately 75% of it is water. If you could harness the power used by your brain you could power a 10 watt light bulb!

Cerebral cortex It is the convoluted or folded outer layer or covering of the two hemispheres. It is around 2mm thick It contains ¾ of the entire brain’s neurons. Its bulges and grooves account for the increased surface area. It is involved with information processing activities such as perception, language, learning, memory, thinking, problem solving, control of voluntary body movements.

The cerebral cortex It is believed that the size of a species’ cerebral cortex is linked to intellectual ability. The bigger the cerebral cortex, the more capable the organism is of intelligent behaviour such as thinking, problem solving and decision making.

Corpus callosum The corpus callosum is a bridge of nerve tissue that connects the left and right cerebral hemispheres. It serves as the main communication pathway or cross over station for neural messages between the two cerebral hemispheres. It comprises over 200 million nerve fibres.

Cerebral hemispheres These are the two almost symmetrical brain structures that appear to be separated by a deep groove (longitudinal fissure) running from the front to back of the brain. They are connected at several points by strands of nerve tissue. They are referred to respectively as the left and right hemispheres. While they share some common functions, they also have specialised functions. Eg. the left hemisphere receives sensory information from the right side of the body and controls movements on the right side. Left hemisphere is primarily involved with language, right hemisphere is primarily involved with spatial tasks and recognition of faces.

Four cortical lobes

The role of the four lobes of the cerebral cortex Control of motor coordination Processing of sensory information Processing Visual information Auditory processing Primary cortex involved in all lobes Association areas

Cortical areas

Cortical areas 1. Sensory cortex areas – receive and process information from the senses. 2. Motor cortex area – receives, processes and sends information about voluntary bodily movements. 3. Association cortex areas – integrate sensory, motor and other information and are involved in complex mental abilities.

Male brain

Female brain

Homer Simpson’s Brain

Now lets make a brain!! Using materials provided, construct and label a brain that includes; - frontal lobe - parietal lobe - occipital lobe - temporal lobe - primary cortex areas associated with each lobe - association areas - wernickes area - brocas area - brain stem - cerebellum

Chapter 5 of text book – The peripheral nervous system Page 271 onwards

The role of the peripheral nervous system The CNS relies on the PNS to provide it with information about both the external world and the body’s internal environment. To carry messages from the CNS to various parts of the body ‘peripheral’ means outlying or surrounding. Therefore the peripheral nervous stem is located

The PNS The PNS is a network of neurons outside the CNS that extends from the top of the head and throughout the body. It is divided into the somatic and autonomic nervous systems.

Divisions of the PNS

Somatic nervous system Initiates all skeletal muscle activity, enabling voluntary movement (E.g. -walking) Transits information from sensory receptors (E.g. - in skin and muscles) to the CNS (sensory function) Controls voluntary movement of skeletal muscles through messages carried from the CNS via motor neurons to the muscles (motor function).

Autonomic nervous system Network of neurons connecting the CNS to the body’s internal muscles, organs and glands Self-regulates independently of the brain, although it is still influenced by the brain. Is automatic and does not require conscious control Functions continuously, whether the person is awake, active, asleep or in a coma Modulates activity rather than initiates activity

Autonomic nervous system cont’d The autonomic nervous system is divided into the sympathetic and parasympathetic nervous system.

Sympathetic nervous system Activates internal muscles, organs and glands to prepare the body for activity, or to confront or flee from a threatening situation (fight-flight response) Increases survival by allowing rapid responses in an emergency situation – sends a message to the adrenal glands to secrete the hormones adrenaline and noradrenaline, which travel around the body via the bloodstream, activating various muscles, glands and organs.

Parasympathetic nervous system Keeps the body working efficiently and counterbalances the activity initiated by the sympathetic nervous system Restores the body to as state of calm, therefore maintaining homeostasis Dominates the sympathetic nervous system most of the time

Clip from internet about Nervous System comparison… Enjoy! http://itc.gsw.edu/faculty/gfisk/anim/autonomicns.swf

Hemispheric specialisations