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? Resting Potential: slightly negative charge. Reach the threshold when enough neurotransmitters reach dendrites. Go into Action Potential. All-or-none response. Transfer of ions across axons membrane causes electrical charge.
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 Black widow spider? Is involved in autonomic nervous system Lack of has been linked to Alzheimers disease & ADD
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 All nerves that are not encased in bone. Everything but the brain and spinal cord. Is divided into two categories….somatic and autonomic.
Somatic Nervous System Controls voluntary muscle movement. Uses motor (efferent) neurons.
Autonomic Nervous System Controls the automatic functions of the body. Divided into two categories…the sympathetic and the parasympathetic
Sympathetic Nervous System Fight or Flight Response. Automatically accelerates heart rate, breathing, dilates pupils, slows down digestion.
Parasympathetic Nervous System Automatically slows the body down after a stressful event. Heart rate and breathing slow down, pupils constrict and digestion speeds up.
Reflexes Normally, sensory (afferent) neurons take info up through spine to the brain. Some reactions occur when sensory neurons reach just the spinal cord. Survival adaptation.
The Brain Made up of neurons and glial cells. Glial cells support neural cells. My fiance is my glial cell. He takes care of me!!!
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
Brain Structures Some scientists divide the brain up into three parts. Hindbrain Midbrain Forebrain Lets talk first about the brainstem
Medulla Oblongata Central Office=keeps your whole body working Located where spinal cord enters the skull Controls heart rate, breathing & blood pressure
Pons Connects hindbrain, midbrain & forebrain together Involved in facial expressions
SPINAL CORD (the nerves) interneurons that carry signals protected by vertebrae & spinal fluid (cushions the nerves)
Cerebellum means little brain located in the back of our head Coordinates muscle movements & emotions
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 that relays info to other areas of the brain controls arousal & ability to focus attention
Limbic System EMOTIONAL CONTROL CENTER of the brain Linked to emotions (fear, anger…) & basic motives (food, sex…) The 4 Fs – Feeding – Fighting – Fear – F (sex) Made up of Hypothalamus, Amygdala, Hippocampus & 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 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 Helps regulate emotion & pain Monitors and guides behavior Helps predict negative consequences
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.
Endocrine System System of glands that secrete hormones. Controlled by the hypothalamus. Ovaries and Testes. Adrenal Gland