The Nervous System It starts with an individual nerve cell called a NEURON.
Neuroanatomy Synapse Neurotransmitters (chemicals held in terminal buttons that travel through synaptic gap)
How does a Neuron fire? Threshold: level of stimulation needed to trigger a neural impulse Action Potential: electrical charge that travels down the axon All-or-none response: neuron either fires or it doesnt, nothing in beteween! Neurotransmitters: chemical messengers that cross synaptic gap b/w neurons INFLUENCES EVERYTHING WE DO!!! Move, feel…everything! Reuptake : sending neuron reabsorbs some of the neurotransmitter
Types of Neurons Sensory Neurons (Afferent): carry sensory information to brain & spinal cord (central nervous system) Motor Neurons (Efferent): carry information from brain & spinal cord to muscles & glands Interneurons: in bran & spinal cord that communicate b/w sensory & motor
Acetylcholine (ACH) Deals with learning, memory, & muscle movement At every junction b/w motor neurons & muscles – When released to our muscles the muscle contracts – When it is blocked muscles are paralyzed & cannot contract Anesthesia? Black widow spider? Is involved in autonomic nervous system Lack of has been linked to Alzheimers disease
Dopamine Involved in movement & posture, alertness, & leveling out mood Cocaine (and other drugs) blocks dopamine reuptake=high Lack of dopamine has been linked to Parkinsons disease Too much has been linked to schizophrenia (overstimulated brain)
Serotonin Involved in mood, appetite, arousal Low levels have been linked to clinical depression, suicide, loss of appetite (anorexia)
GABA (gamma amino-butyric acid) In Central Nervous System Induces relaxation & sleep Balances the brain Too little = insomnia, anxiety, epilepsy
Glutamate Involved in memory & learning Low levels = interferes with memory & learning, sluggish, difficulty concentrating High levels = must be reuptook? or it can destroy neurons
Endorphins Natural pain killers Feeling of euphoria, pleasurable emotions Opiates (morphine, codeine…) bind to receptors – Many of our most addictive drugs deal with endorphins Produced during exercise – gym rats
Drugs can be….. Agonists- make neuron fire Antagonists- stop neural firing Reuptake Inhibitors- block reuptake
Central Nervous System The Brain and spinal cord CNS
Peripheral Nervous System Peripheral: sensory & motor neurons that connect the Central NS to the rest of the body – Its how the brain & spinal cord communicate w/ sensory receptors, muscles & glands – Travel through nerves (bundled axon cables that connects cns to eveything) Is divided into two categories….somatic and autonomic
Somatic Nervous System Controls voluntary muscle movement Uses motor neurons Lets make a list!
Autonomic Nervous System Controls the automatic functions of the body – Glands, organs, heartbeat, digestion, etc… Think AUTOMATIC Divided into two categories…the sympathetic and the parasympathetic
Sympathetic Nervous System When you are stressed: – Automatically accelerates heart rate, breathing, raises blood sugar, sweat to cool you down… Fight or Flight Response! – You body feels sympathy for you b/c it thinks you are about to die so it gets you ready to fight or run
Parasympathetic Nervous System Automatically slows the body down after a stressful event Heart rate and breathing slow down, lowers blood sugar, etc… Think PARACHUTE
Reflexes Automatic response to stimuli Normally, sensory neurons take info up through spine to the brain – Some reactions occur when sensory neurons reach just the spinal cord (interneurons) Survival adaptation?
Brain Structures Some scientists divide the brain up into three parts. Hindbrain Midbrain Forebrain Lets talk first about the brainstem (hindbrain)
Medulla Oblongata Central Office=keeps your whole body working Located where spinal cord enters the skull Controls heart rate, breathing & blood pressure
Pons Located above medulla Communicates between cerebellum & other parts of brain Involved in sleep & arousal (awake) Some think involved in dreaming
SPINAL CORD (the nerves) interneurons that carry signals protected by vertebrae & spinal fluid (cushions the nerves)
Thalamus Located in Forebrain Brains Sensory Switchboard – 2 egg shaped structures receives information from all the senses (except smell) & routes it to the brain regions that deal with vision, hearing, taste & touch its the main traffic hub en route to other destinations
Reticular Formation (reticular activating system) Located between your ears Finger-shaped network of neurons located between spinal cord & thalamus Sensory info travels from spinal cord to thalamus & some passes thru RF which filters info & relays it to other areas of the brain controls arousal (alert) – Stimulate that cat! Or put in in a coma
Cerebellum means little brain located in the back of our head Coordinates muscle movements, balance, & emotions
Limbic System EMOTIONAL CONTROL CENTER of the brain Linked to emotions (fear, anger…), memory & motivation (food, sex…) The 4 Fs – Feeding – Fighting – Fear – F (sex ) Made up of: *Hypothalamus*Hippocampus *Amygdala*Cingulate Gyrus
Hypothalamus the brains thermostat perform specific bodily maintenance duties (eating, drinking, body temperature, sex drive…), takes orders from the other parts of the brain – pleasure center Orchestrates the sympathetic nervous & endocrine systems – interplay b/w endocrine & nervous systems, both influence each other – EX: thinking about sex can trigger your body to secrete hormones
Hippocampus and Amygdala Hippocampus is involved in memory processing (creating new memories) – Think lost on campus as a freshmen on first day – Shaped like a seahorse – Damage to this area will prevent you from forming new memories Amygdala is vital for our basic emotions – Expressions of Fear & Aggression/Frustration
Cingulate Gyrus Latin for belt emotional responses to pain regulates aggressive behavior Helps predict negative consequences
The Brain Made up of neurons and glial cells Glial cells are the housekeepers that support & provide nutrition to neural cells My husband is my glial cell. He takes care of me (and cleans the house)!!!
Cerebral Cortex The wrinkled outer layer of our brain Laid out it would be about the size of a large pizza (yum!) YOUR BODYS ULTIMATE CONTROL & INFO PROCESSING CENTER Thinking, perceiving, speaking This part of our brain separates us from all other animals
Areas of the Cerebral Cortex Divided into eight lobes, four in each hemisphere (frontal, parietal, occipital and temporal) Any area not dealing with our senses or muscle movements are called association areas – Deal with higher mental functions like learning, remembering, thinking & speaking
Frontal Lobe Deals with higher level thought & reasoning – Making plans, forming judgments, performing movements Motor Cortex: controls voluntary movements Prefrontal Cortex: problem solving & emotion Brocas Area: left hemisphere in frontal lobe, controls ability to speak (muscles) – Brocas Aphasia: damage to Brocas area will impair speaking
Parietal Lobes Located at the top of our head Receives sensory info about temperature, pressure, texture, & pain Somato-sensory cortex: registers and processes touch and movement sensations
Temporal Lobes Located above the ears Process sound sensed by ears Wernickes area: processes the words we hear spoken – Wernickes Aphasia: impairs your ability to understand words Angular Gyrus: responsible for understanding written language
Occipital Lobes Located in the back of our head Handles visual input from eyes Right half of each retina goes to left occipital lobe and vice versa (seriously!!!)
Corpus Callosum & Basil Ganglia Corpus Callosum: a large band of neural fibers that connect the 2 hemispheres of the brain (well talk about what happens when you cut this this soon) Basil Ganglia: group of neurons that learns, remembers, & coordinates voluntary movement (Williams in Zumba!!!!)
Hemispheres Divided into a left and right hemisphere. Contralateral controlled- left controls right side of body and vice versa. Brain Lateralization. Lefties are better at spatial and creative tasks. Righties are better at logic.
Split-Brain Patients Corpus Collosum attaches the two hemispheres of cerebral cortex. When removed you have a split-brain patient.
Brain Plasticity The ability for our brains to form new connections after the neurons are damaged. The younger you are, the more plastic your brain is.
Ways to study the Brain!!! Accidents: Phineas Gage.
Lesions Cutting into the brain and looking for change. Brain tumors also lesion brain tissue.
Less Invasive ways to study the Brain Electroencephalogram (EEG) Computerized Axial Tomography (CAT) Magnetic Resonance Imaging (MRI) Positron Emission Tomography (PET) Functional MRI CHECK OUT LINK ON WEBSITE FOR MORE INFO!
Endocrine System System of glands that secrete hormones. Controlled by the hypothalamus. Pituitary=master gland Ovaries and Testes. Adrenal Gland