The Nervous System Nerves, nerves everywhere!
Purpose of the Nervous System The information intake and response system of the body. Coordinates all body functions, voluntary and involuntary! Responds to stimuli anything that a living organism can understand and trigger a reaction to. Basically, it tells your body what to do, all the time!
Basic response pattern to a stimuli 1. Receives information (internally and externally) 2. Transmit information to brain 3. Stores information in brain 4. Sends brain s response to specific parts of the body to produce a reaction **All happening almost instantaneously**
Key parts of the Nervous System Two sections 1. Central Nervous System, CNS (Brain and spinal cord): Part of the system that interprets and responds to stimuli 2. Peripheral Nervous System, PNS: Connects entire body to CNS; part that receives stimuli and sends CNS response to stimuli Key in both sections of the Nervous system is the cell responsible for sending and receiving messages.the neuron!
Key parts of the Nervous System
The Neuron Specialized cell found throughout the entire nervous system. Function: Send and receives messages Shape: Irregular shape; does not look like typical animal cell Regeneration: Not really You can t grow neurons everywhere; they don t tend to replace themselves Dentate gyrus is one area in the brain where scientists have recently found neurons regenerating/increasing in numbers
The Neuron Four key components 1. Dendrites: Top of neuron, pick up stimulus 2. Cell body: Stimulus interpreted, nerve impulse developed to be sent 3. Axon: Transports nerve impulse to axon terminal 4. Axon terminal: End of neuron, nerve impulse triggers neurotransmitter to be released into synapse
Nerve impulse 1. Dendrite receives stimuli, sends stimuli to cell body 2. Cell body interprets stimuli 3. Cell body sends nerve impulse through axon to axon terminal 4. Nerve impulse at terminal triggers neurotransmitter to be released 5. Neurotransmitter travels through synapse to dendrite of second neuron 6. Repeat step 1
Dendrite Axon Synapse 4 6 5 Cell Body 2 3 Axon Terminals Nucleus Cell Body 1 Dendrite
The Nerve Bundle of neurons! Structure: cable-like Axon of neuron
The Nerve Three main types 1. Sensory receptors receive stimuli; translate it into impulse 2. Sensory nerves take impulse from sensory receptor, send stimuli to brain 3. Motor nerves take brain s response to stimuli, sends it reply to muscles in body
The Central Nervous System Components: Brain and Spinal Cord Protected by: Cranium Made up of two different types of tissue 1. Grey matter more cell bodies than white matter Found in the brain (exterior) and spinal cord (centre) 2. White matter more long axons than grey matter (white colour due to myelin sheath) Found in the brain (centre) and spinal cord (exterior)
The Brain Large mass of nerve cells (of either grey or white matter) The brain is split into to halves called hemispheres The left hemisphere controls the right side of the body The right hemisphere controls the left side of the body The hemispheres are further sub-divided into different regions, responsible for certain tasks.
The Brain Main components of the brain 1. Cerebrum Voluntary movement, sense interpretation, intelligence, emotion, (What makes us human!) a. Frontal lobe Cognition (knowledge), memory (related to emotions), personality b. Temporal lobe Auditory and visual processing, long term memory c. Parietal lobe Spatial orientation, speech, pain and touch sensation d. Occipital lobe Visual processing, dream centre
The Brain 2. Cerebellum Balance, movement coordination 3. Brain stem Involuntary movements, interpretation of internal stimuli (Stimuli coming from body itself)
Spinal Cord Long nerve bundle, extending from brain stem to the base of the vertebral column
Spinal Cord 1 st Function: Carries information to and from the brain 31 spinal nerves attached to the spinal cord send nerve impulses throughout the body Protected by: Vertebral column (Spinal column) 2 nd Function: Reflex Arc centre
Spinal Cord 2 nd Function: Reflex Arc centre
Reflex Rapid, involuntary reaction to a stimuli Key: emergency reaction Brain is only informed after reflex arc has taken place!!! Reflex arc path the nerve impulse takes in reflex reaction
a Reflex Arc of a finger being pricked