Divisions of the Nervous System
Central Nervous System CNS– relays messages, processes information, and analyses information The two parts are Brain Spinal Cord
Outer Protection of CNS Meninges- three layers of connective tissue that surround the brain and spinal cord Cerebrospinal fluid- fluid surrounding the brain that acts as a cushion. Spinal tap – samples cerebrospinal fluid to test for bacteria or protein
Parts of the Brain Cerebrum Largest portion of the brain The wrinkles increase the surface area which increases the number of neurons Contains areas of higher reasoning and sensory interpretation
Parts of the Brain Cerebrum con’t The left half analyzes the information from the right side of the body and vice versa. Made of two layers Grey matter – tightly packed cell bodies White matter – tightly packed axons with myelin sheathes
Parts of the Brain Cerebellum Located at the back of the skull Coordinates and balances muscle movement
Parts of the Brain Brain Stem Connects the spinal cord and the brain Controls most important involuntary actions like blood pressure, heart rate, breathing and swallowing.
Parts of the Brain Thalamus Hypothalamus Receives information from the body and relays the information to the correct section of the brain. Hypothalamus Control center for hunger, thirst, fatigue etc.
Spinal Cord A thick bundle of nerve axons that connect the brain to the rest of the body Reflexes – a quick, automatic response – is controlled by the spinal cord
Peripheral Nervous System All nerves and cells located outside of the spinal cord Somatic Nervous system Controls skeletal muscles Autonomic Nervous System Controls involuntary responses.
Reflex Arcs Five parts: Sensory Receptor – takes in stimulus Sensory Neuron- relays impulse to spinal cord Interneuron-relays impulse to motor neuron Motor neuron- carries impulse to muscle Effector – the muscle that moves.