THE NERVOUS SYSTEM

THE NERVOUS SYSTEMThe Functions of the Nervous SystemThe nervous system coordinates and controls body activityThe nervous system detects and processes internal and external information and formulates appropriate responsesThe Structures of the Nervous SystemThere are two major divisions of the nervous system:The central nervous system (CNS) consists of the brain and spinal cordThe peripheral nervous system (PNS) consists of the cranial and spinal nerves, autonomic nervous system.

The Structures of the Nervous SystemThe basic unit of the nervous system is the neuronThere are three types of neurons:sensory (also called afferent)associativemotor (also called efferent)Parts of the NeuronThe neuron consists ofa cell body (soma)dendritesCarry impulses toward the cell bodyan axonCarries impulses away from the cell body

The GapThe space between two neurons or between a neuron and receptor is the synapseChemical substances called neuro-transmitters are released into the space to allow information to be relayed

Surrounding StructuresMyelin is a protective covering over some nerve cells including parts of the spinal cordMyelin serves as an electrical insulatorMyelin is interrupted at regular intervals along the length of a fiber by gaps called nodes of Ranvier

Activity time! The CNSThe central nervous system is made up of the brain and spinal cord

The MeningesThe meninges are a three-layered membrane that surrounds the CNSThe three layers of the meninges are the dura mater, arachnoid membrane, and the pia mater

The CSFCerebrospinal fluid (CSF) is the clear, colorless ultrafiltrate that nourishes, cools, and cushions the CNSCSF is made by the choroid plexus that lines the ventricles of the brain

The BrainThe brain is the enlarged and highly developed portion of the CNS that lies in the skull and is the main site of nervous controlThe cranium is the portion of the skull that encases the brain

Lobes all around!Frontal Lobe- planning, reasoning, judgment, and memoryTemporal Lobe speech, auditory perception, and emotionsParietal Lobe touch, numbers, taste, and temperature.Occipital Lobe color recognition, visual perception

The Brain DivisionsThe brain is divided into three main parts:Cerebrum is the largest part and is responsible for receiving and processing informationCerebellum is the second largest part that coordinates muscle activityBrainstem connects the cerebral hemispheres with the spinal cord and supports basic life functions

The Spinal CordThe spinal cord is the continuation of the medulla oblongata of the brainstem

The spinal cord passes through an opening in the occipital bone called the foramen magnum

The spinal cord carries the tracts that influence the innervation of the limbs and lower part of the body and is the pathway for impulses going to and from the brain

The DiscsThe spinal cord is housed within vertebrae to protect it from injury

The vertebrae are protected from each other by intervertebral discs located between the vertebrae

Intervertebral discs are layers of fibrocartilage that form pads separating and cushioning the vertebrae from each other

The PNSThe peripheral nervous system consists of cranial & spinal nerves and the autonomic nervous systemThe spinal nerves arise from the spinal cord and supply sensory and motor fibers to the body region associated with their emergence from the spinal cord.

The ANSThe autonomic nervous system is that part of the peripheral nervous system that innervates smooth muscle, cardiac muscle, and glandsThere are two divisions of the ANS:sympathetic: fight or flightparasympathetic: maintains normal body function

Review

Nervous Systemhttp://www.youtube.com/watch?v=UabDiuTtU0M