The Human Nervous System

CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM BRAIN SPINAL CORD SOMATIC NERVOUS SYSTEM AUTONOMIC NERVOUS SYSTEM SYMPATHETIC NERVOUS SYSTEM PARASYMPATHETIC NERVOUS SYSTEM

The Nervous System Nervous system is a delicate and complex communication system made up of billions of connected nerve cells (neurons), transmitting information around our body Consists of the brain, spinal cord and nerves throughout our bodies There are 2 main subdivisions of the Nervous System- The Central Nervous System (CNS) and the Peripheral Nervous System (PNS) CNS= Brain and Spinal Cord PNS= all other nerves in our bodies

CENTRAL NERVOUS SYSTEM BRAIN SPINAL CORD

CNS- The Brain Known as the “Master Organ” because it overseas everything we think, feel and do. Located in the skull and has a wrinkled appearance Can be subdivided into 3 regions: hindbrain (back), midbrain (middle) and forebrain (front)

CNS- Spinal Cord The body’s information highway! Complex cable of nerve fibres stretching from the base of the brain to the lower back Connects the brain to other parts of the body through its connection with the PNS Receives sensory information from the PNS and transmits it to the brain Transmits messages (responses) from the brain to the rest of the body (via PNS)

Neurons (Nerves) Neurons are nerve cells and the basic units involved in all behaviours They receive and send electrical signals between the CNS and our bodies and also signal between themselves. Sensory (afferent) neurons- carry information from the senses to Interneurons in the CNS for interpretation Interneurons- found only within the CNS and provide the link between sensory and motor neurons Motor (efferent) neurons- transmit movement messages from Interneurons in the CNS outwards to the muscles and body for action.

Activity: Copy in your books a diagram of a Neuron and complete the mix n Match worksheet labelling the parts of a neuron. Now build your very own Neuron out of Pipe- Cleaners!

Peripheral Nervous System (PNS) Peripheral meaning “border” All of the nerves outside the brain and spinal cord Carries messages to and from various muscles, glands and senses throughout the body Further divided into 2 subsections: the Somatic and Autonomic nervous system

PERIPHERAL NERVOUS SYSTEM SOMATIC NERVOUS SYSTEM AUTONOMIC NERVOUS SYSTEM

PNS- Somatic Nervous System A branch of the PNS that controls our voluntary movement Also called the Skeletal Nervous System because it connects the skeletal muscles with the CNS allowing voluntary movement Carries Sensory Information TO the CNS Carries Motor Information FROM the CNS Messages can only travel in one direction, so the PNS has two different pathways for carrying messages to and from the CNS

PNS- Autonomic Nervous System Carries messages between the CNS and the heart, lungs and other internal organs and glands The ANS regulates and controls the functioning of internal organs “automatically” EG- heart rate, breathing, digestion, salivation ect ANS functions independently of the CNS Has 2 subdivisions: Sympathetic Nervous System and Parasympathetic Nervous System

PERIPHERAL NERVOUS SYSTEM AUTONOMIC NERVOUS SYSTEM SYMPATHETIC NERVOUS SYSTEM PARASYMPATHETIC NERVOUS SYSTEM

Autonomic Nervous System: Sympathetic Nervous System Arouses the body when you are experiencing an extreme emotion or feel threatened Activates the “fight or flight” response Eg- Bungy Jumping, hearing footsteps in a dark alley Fight: Stay and “fight” the threatening situation Flight: Take “flight” and run away from the situation

Autonomic Nervous System: Parasympathetic Nervous System Usually the dominant system maintaining a sense of homeostasis (balance) in normal functioning. Calms or restores the body to the normal state of functioning opposite to that of the Sympathetic NS Slow in returning the body back to normal because it takes longer to remove the hormones initially released by the Sympathetic NS for quick action.

CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM BRAIN SPINAL CORD SOMATIC NERVOUS SYSTEM AUTONOMIC NERVOUS SYSTEM SYMPATHETIC NERVOUS SYSTEM PARASYMPATHETIC NERVOUS SYSTEM