Contains the full lesson along with a supporting toolkit, including teachers’ notes.
The Human Brain
The central nervous system (CNS) in humans comprises the brain and spinal cord. The brain has three main parts: forebrain, midbrain and hindbrain. The forebrain, comprising the cerebrum or cerebral cortex is by far the largest part of the brain. It consists of highly folded left and right cerebral hemispheres, with interconnecting fibres. The cerebrumreceives and interprets sensory information; it controls voluntary movement and it is responsible for controlling all our higher order functions such as language, intelligence, memory, emotions and personality.
The midbrain consists of the thalamus, hypothalamus andpituitary gland. The thalamus is the main relay centre of the brain. It operates rather like a telephone exchange receiving information and passing it on. The hypothalamus is responsible for homeostasis; it regulates factors such as body temperature, water-salt balance and appetite. The Pituitary gland is the master gland of the endocrine system. The hindbrain is made up of themedulla oblongataand the cerebellum. The medulla controls involuntary muscles such as those involved in heartbeat, breathing and swallowing, while the cerebellumregulates muscle co-ordination and controls balance.
What are Brain Cells like?
The structural and functional unit of the nervous system is the neuron. The main part of a neuron is the cell body containing the normal cell organelles. Dendrites from the cell body receive messages or impulses that travel along the axon to the axon terminal(s).
What is the Route taken by Nerve Impulses?
Sensory neurons carry impulses from the sense organs andreceptors to the central nervous system (CNS). Here the impulse is passed to interconnecting neurons within the CNS and finally an impulse is sent along a motor neuron from the CNS to an effector organ, usually a muscle or gland. This route from sense organ or receptor to effector organ via interconnecting neurons in the CNS is called the pathway of nerve transmission.