The Nervous system
What is the nervous system? The nervous system of the human being is responsible for sending, receiving, and processing nerve impulses throughout the body. All the organs and muscles inside your body rely upon these nerve impulses to function.
What makes up the nervous system? The nervous system consists of the brain, spinal cord and a complex network of neurons and is divided into 2 main systems; Central and Peripheral
Central nervous system The central nervous system is made up of the brain and the spinal cord which is protected by the bones of the scull and vertebrae. Within is a fluid that cushions and adds extra protection, called cerebrospinal fluid.
Peripheral nervous system This consists of all nerves and nerve endings outside the protection of the scull and vertebrae. There are two types of cell that form this system. Can you think of what they may be called? Hint; they help you feel and get you moving!!!!
Motor and Sensory
Sensory nerves What do they do? Carry messages from organs and external stimuli to the central nervous system to be translated and acted upon.
Motor nerves What do they do? Motor nervous system cells carry information from the CNS to organs, muscles, and glands. The motor nervous system is divided into the somatic nervous system and the autonomic nervous system.
somatic nervous system The somatic nervous system controls skeletal muscle as well as external sensory organs such as the skin. This system is said to be voluntary because the responses can be controlled consciously. Reflex reactions of skeletal muscle however are an exception. These are involuntary reactions to external stimuli.
autonomic nervous system The autonomic nervous system controls involuntary muscles, such as smooth and cardiac muscle. This system is also called the involuntary nervous system. The autonomic nervous system can further be divided into the parasympathetic and sympathetic divisions.
parasympathetic division The parasympathetic division controls various functions which include inhibiting heart rate, constricting pupils, and contracting the bladder. Rest and Digest
sympathetic division The nerves of the sympathetic division often have an opposite effect when they are located within the same organs as parasympathetic nerves. Nerves of the sympathetic division speed up heart rate, dilate pupils, and relax the bladder. The sympathetic system is also involved in the flight or fight response. This is a response to potential danger that results in accelerated heart rate and an increase in metabolic rate.
Task In pairs use the task sheets provided to try and remember as much as you can about the nervous system.