AP Biology Nervous System

Regents Biology Why do animals need a nervous system?  What characteristics do animals need in a nervous system?  fast  accurate  reset quickly Remember… think about the bunny… Poor bunny!

Regents Biology Nervous System  Central nervous system  brain & spinal cord  Peripheral nervous system  nerves from senses  nerves to muscles cerebrum cerebellum spinal cord cervical nerves thoracic nerves lumbar nerves femoral nerve sciatic nerve tibial nerve

Regents Biology Nervous system cells dendrites cell body axon synapse  Neuron  a nerve cell signal direction signal direction

Regents Biology Parts of a Neuron Cell Body 1. Cell Body – Contains organelles including a nucleus Dendrites 2. Dendrites – Short fibers that receive the impulse Axon 3. Axon – Long fibers: ex: 1 micrometer long that transmit impulses Myelin 4. Myelin – A fatty covering that speeds up transmission of the impulse – made by Schwann cells

Regents Biology Fun facts about neurons  Most specialized cell in animals  Longest cell  blue whale neuron  meters  giraffe axon  5 meters  human neuron  1-2 meters Nervous system allows for 1 millisecond response time

Regents Biology Myelin sheath signal direction  Axon coated with insulation made of myelin cells  speeds signal  signal hops from node to node  330 mph vs. 11 mph myelin sheath Multiple Sclerosis  immune system (T cells) attacks myelin sheath  loss of signal Multiple Sclerosis  immune system (T cells) attacks myelin sheath  loss of signal

Regents Biology Synapse Junction between nerve cells  1st cell releases chemical to trigger next cell  this is where drugs affect nervous system

Regents Biology Types of neurons sensory neuron (from senses) interneuron (brain & spinal chord) motor neuron (to muscle)

Regents Biology Human brain

Regents Biology Primitive brain  The “lower brain”  medulla oblongata  pons  cerebellum  Functions  basic body functions  breathing, heart, digestion, swallowing, vomiting  homeostasis  coordination of movement

Regents Biology Higher brain  Cerebrum  hemispheres  left = right side of body  right = left side of body  Corpus callosum  major connection between 2 hemispheres

Regents Biology Division of Brain Function  Left hemisphere  “logic side”  language, math, logic operations, vision & hearing details  fine motor control  Right hemisphere  “creative side”  pattern recognition, spatial relationships, non-verbal ideas, emotional processing, parallel processing of information

Regents Biology Cerebrum specialization  Regions of the cerebrum are specialized for different functions  Lobes  frontal  temporal  occipital  parietal

Regents Biology Limbic system Controls basic emotions (fear, anger), involved in emotional bonding, establishes emotional memory

Regents Biology Simplest Nerve Circuit  Reflex, or automatic response  rapid response  automated  signal only goes to spinal cord  no higher level processing  advantage  essential actions  don’t need to think or make decisions about  blinking  balance  pupil dilation  startle

Regents Biology Eye Blink or Pain Withdrawal Reflex Effector (muscle) Spinal cord Interneuron Gray matter White matter Motor neuron Sensory neuron Receptor in skin Stimulus

AP Biology cerebrum cerebellum spinal cord cervical nerves thoracic nerves lumbar nerves femoral nerve sciatic nerve tibial nerve Any Questions??