The Central Nervous System Year 12 Psychology Unit 3 – The Conscious Self Area of Study 1: Mind, Brain and Body Chapter 4 PART 3 –Neurons
The Spinal Cord Cable-like column of nerve fibres that runs from the base of the brain to the lower back. Encased in vertebrae which extend further than the actual spinal cord. Transmits sensory and motor information between the brain and body. Damage can result in paralysis: the higher up on the spine the damage occurs, the more connections between brain and body are lost. The linking ‘pipeline’ that integrates our central and peripheral nervous systems.
The Spinal Cord Ascending tracts send sensory information up to the brain; descending tracts send motor information down to the body. Two major components: White matter: axons that are bundled together and run the length of the spinal cord. Grey matter: mainly located near the centre of the spinal cord, made up of cell bodies, axons and dendrites. Controls spinal reflex (see box 4.9 on page 211)
Neurons Cells specialised to receive, process and/or transmit information to other cells within the body. Also known as nerve cells. The basic unit of the nervous system. About 200 different types in CNS alone. See page 210 for diagrams. See box 4.10 on page 212 for description of the transmission process within an individual neuron.
Neurons: Three Overall Types/Categories Sensory Neurons (aka afferent neurons): Carry information from sensory organs to the brain. Receive information from external environment (senses) and internal environment (muscles, organs & glands). Generally only respond to a particular type of stimulation, specific to what that neuron is in charge of. Sensory receptor site Nervous System/Brain Specific cortex area
Neurons: Three Overall Types/Categories Motor Neurons (aka efferent neurons): Carry information from brain to muscles, organs, glands. Enable bodily movement and internal functioning. Receive and act on messages received from interneurons. Motor Cortex Spinal Cord Specific body part
Neurons: Three Overall Types/Categories Interneurons (aka connecting neurons): Make the connection between sensory and motor neurons. Relay messages from one type of neuron to another. Exist only in the Central Nervous System (brain and spinal cord). Sensory Neuron Motor Neuron