The Nervous System - PC\|MAC

The Nervous System - PC\|MAC

The Nervous System Ode To The Brain Anatomy & Physiology The Basics: The nervous system is your body's decision and communication center. The central

nervous system (CNS) is made of the brain and the spinal cord The peripheral nervous system (PNS) is made of nerves. Neurons A neuron is a nerve cell that is the basic building block of the nervous system and are specialized to transmit information

throughout the body. Job: communicating information in both chemical and electrical forms. 3 main types: 1. Sensory neurons (afferent) carry information from the sensory receptor cells throughout the body to the brain. 2. Motor neurons (efferent) transmit information from the brain to the muscles of the body. 3. Interneurons are responsible for communicating information between different neurons in the body. Well get back to these later..

Do Now! 1. What are the two main parts of the nervous system? 2. What organs are these two parts made up of? 3. What is a neuron? 4. What are the 3 different kinds of neurons? Use the definitions below to correctly label this neuron

axon - the long extension of a neuron that carries nerve impulses away from the body of the cell to other neurons. axon terminals - the hair-like ends of the axon cell body - the cell body of the neuron; it contains the nucleus (also called the soma)

dendrites - the branching structure of a neuron that receives messages (attached to the cell body) myelin sheath - the fatty substance that surrounds and protects some nerve fibers node of Ranvier - one of the many gaps in the myelin sheath - this is where the action potential occurs during saltatory conduction along the axon nucleus - the organelle in the cell body of the neuron that contains the genetic material of the cell Schwann's cells - cells that produce myelin - they are located within the myelin sheath. Neurons

Neuron Parts: Soma: body of the cell (main space; contains nucleus/DNA) Dendrites: receive messages from neurons Axon: sends messages to other neurons Anatomy of a nerve Two parts of Nervous system & Neuron video clip The Nervous System:

The Teenage Brain on NOVA: s=frol02p392&continuous=1 How messages are sent and received Neurons send messages electrochemically. This means that chemicals cause an electrical signal. Chemicals in the body are "electricallycharged" -- when they have an electrical charge, they are called ions.

Watch Bill Nyes Greatest Science Discoveries on Neutrotransmitters. How messages are sent and received continued Resting Membrane Potential : At rest, there is an excess of negative ions inside the neuron compared to the outside. How messages are sent and received

continued viewVideo.php? Action Potential video_id=153535 When a message is incoming, the membrane opens at that point, and positively charged ions flow in. This process is repeated along the length of the membrane, creating the neural impulse that travels down the axon, causing the neuron to fire.

Electrical changes during the action potential. The incoming message must be above a certain threshold to cause a neuron to fire. After it fires, the neuron is returned to its resting state. This process happens very quickly, and within a few thousandths of a second the neuron is ready to fire again. Myelin and Nodes of Ranvier The axons of the nerve cells are sheathed in a smooth fatty protein called myelin which insulates the axon. It considerably increases the speed that nerve impulses travel along the axon.

Without the myelin, the axons would have to be about one hundred times their volume to achieve the same speed of nerve transmissions. The myelin is wrapped around the axon in many thin layers. The myelin does not enclose the axon in one entire sheath, but has gaps at intervals called the nodes of Ranvier. What causes the change in potential to occur? 1.

A stimulus causes the sodium gates (channel) to open and, because there's more sodium on the outside than the inside of the membrane, sodium then diffuses rapidly into the nerve cell. 2. All these positively-charged sodium ions rushing in causes the membrane potential to become positive (the inside of the membrane is now positive relative to the outside). The sodium channels open only briefly, then close again. 3. The potassium channels then open, and, because there is more potassium inside the membrane than outside,

positively-charged potassium ions diffuse out. As these positive ions go out, the inside of the membrane once again becomes negative with respect to the outside. From One To The Next A chemical message (called a neurotransmitter) passes from the sending neuron to the receiving neuron. The neurotransmitters leave the sending neuron and enter the space between the sending and receiving neurons. This space is called the synapse or synaptic cleft.

The neurotransmitters then hook up to a receptor on the receiving neuron to deliver their message. Once neurotransmitters have sent their message, they can be reabsorbed by the sending neuron in a process called reuptake. Reuptake allows the messengers to be reused. Two of these neurotransmitters are serotonin and

norepinephrine Reuptake of serotonin occurs when some of the serotonin that is passed from the presynaptic neuron is recycled back into that neuron (see upward arrows and F). SSRIs (P) block this reuptake by blocking the channels (B) which allow for this reuptake of the serotonin (C). This increases the amount of serotonin in the synaptic cleft that can bind with receptors on the postsynaptic terminal. Antidepressant Meds SSRI Low levels of serotonin and norepinephrine in the synapse are associated with

depression and sadness. Some medications used to treat depression work by increasing the amount of certain neurotransmitters that are available to carry messages. Antidepressants, such as selective serotonin reuptake inhibitors, or SSRIs, work by slowing or blocking the sending neuron from taking back the released serotonin. In that way, more of this chemical is available in the synapse. The more of this neurotransmitter that is available, the more likely the message is received, and depression is reduced.

MAO INHIBITORS: The antidepressants known as MAO inhibitors, or MAOIs, affect neurotransmitters differently. Monoamine oxidase (MAO) is a natural enzyme that breaks down neurotransmitters. The drug MAOI disrupts the action of the enzyme MAO. In that way, there is an increase in the amount of neurotransmitters in the

synapse, making more messengers available to the receiving neuron, and thus reducing depression. Neuron parts Animated visual: cz/books/bio_07/get_chapter_group.htm? cin=9&rg=animated_biology&at=animated _biology&var=animated_biology Quiz Time!

Name the .. 1. Part of the neuron that releases neurotransmitters into the synaptic cleft. 2. Fatty material that surrounds some axons. 3. Part that takes information away from the cell body. 4. The gaps in the myelin sheath. 5. Part of neuron that contains the nucleus. 6. Part that takes information to the cell body. 7. Organelle in neuron that contains genetic material. Answers are: 1. Axon terminal

4. Nodes of Ranvier 2. Myelin 5. Soma 3. Axon 6. Dendrites 7. Nucleus

The Central Nervous System Interesting Facts! young frankenstein part 1 The central nervous system is divided into two parts: the brain and the spinal cord. The average adult human brain weighs 1.3 to 1.4 kg (approximately 3 pounds). The brain contains about 100 billion nerve cells (neurons) and trillions of "support cells" called

gila. The spinal cord is about 43 cm long in adult women and 45 cm long in adult men and weighs about 35-40 grams. The vertebral column, the collection of bones (back bone) that houses the spinal cord, is about 70 cm long. Therefore, the spinal cord is much thanStory: the vertebral column. The shorter Brain: The Inside

The CNS: The Brain The cerebrum -- which is just Latin for "brain" -is the newest (evolutionarily) and largest part of the brain as a whole. It is here that things like perception, imagination, thought, judgment, and decision occur. The surface of the cerebrum -- the cerebral cortex -- is composed of six thin layers of neurons (nerve cells) and is refered to as the grey matter. It sits on top of a large collection of white

matter pathways. The cortex is heavily convoluted with ridges called gyri and valleys called sulci. If you were to spread the cortex out, it would actually take up about 2 1/2 square feet (2500 sq cm). It includes about 10 billion neurons, with about 50 trillion synapses! The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe.

The Brain The cerebral cortex is comprised of the: frontal lobe, parietal lobe, occipital lobe, and temporal lobe. What do each of these lobes do?

Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving Functions associated with the frontal lobes: Conscious thought Concentration Perseverance Judgment Attention span Impulse control - self monitoring and supervision

Problem solving Organization Critical thinking Forward thinking Ability to feel and express emotions Empathy YouTube - NEURONS AND NEURO-TRANSMITTERS What do each of these lobes do? Frontal Lobe- associated with reasoning,

planning, parts of speech, movement, emotions, and problem solving Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli Parietal Lobe The parietal lobes can be divided into two functional regions. One involves sensation and perception and the

other is concerned with integrating sensory input, primarily with the visual system. What do each of these lobes do? Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli Occipital Lobe- associated with visual

processing Occipital lobes The OC are the center of our visual perception system. They are not particularly vulnerable to injury because of their location at the back of the brain, although any significant trauma to the brain could produce subtle changes to our visual-perceptual

system, such as visual field defects. What do each of these lobes do? Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli Occipital Lobe- associated with visual processing Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech

The senses of the body (speech, hearing, feelings, seeing and memory) and control of the muscles, are part of the grey matters function. TEMPORAL LOBES: Located at sides of head above ears, the temporal lobes form the wings of the soul of our living caduceus. Functions: The dominant side is usually the left hand side and governsHearing ability Understanding and processing language

Memory acquisition - particularly long term memory Some visual perceptions Categorization of objects. The no dominant side or right side governsRecognition of facial expressions Decoding vocal intonation Rhythm Music Visual learning How your memory works? braindominance.htm Left vs. Right side brain test The right hemisphere controls the left side of the body, and the left hemisphere controls the right side. A deep furrow divides

the cerebrum into two halves, known as the left and right hemispheres. Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. The corpus callosum is a bundle of axons which connects these two

hemispheres. Do Now! 1. What are the 4 parts of the cerebrum? 2. The convolutions of the cerebrum are comprised of ridges and valleys. What are the ridges called? The valleys? 3. What part of the brain is dedicated to visual perceptions? 4. What part of the brain is associated with reasoning, planning, parts of speech, movement, emotions, and problem solving?

5. What part of the brain is associated with movement, orientation, recognition, perception of stimuli? 6. What part of the brain is associated with perception and recognition of auditory stimuli, memory, and speech? 7. What is the deep furrow that divides the cerebrum into two halves known as? The Cerebellum The cerebellum, or "little brain", is similar to the cerebrum in that it has

two hemispheres and has a highly folded surface or cortex. CEREBELLUM: Located at the base of the skull, and attached to the rear of the brain stem. Functions: Coordination of voluntary movement posture Balance and equilibrium Some memory for reflex motor acts.

Limbic System: System The limbic system, often referred to as the "emotional brain", is found buried within the cerebrum. Like the cerebellum, evolutionarily the structure is rather old. This system contains the: 1. thalamus (almost all sensory information enters this structure where neurons send that information to the overlying cortex ), 2. hypothalamus (functions including homeostasis, emotion, thirst,

hunger, circadian rhythms, and control of the autonomic nervous system. In addition, it controls the pituitary ) 3. amygdala (memory, emotion, and fear ), 4. hippocampus (important for learning and memory, for converting short term memory to more permanent memory, and for recalling spatial relationships in the world about us) Sense of smell BRAIN STEM: Located deep in the brain, leads to spinal cord. Often referred to as The 'Reptilian' or 'Primitive' Brain. The

majority of the cranial nerves exit from the brain stem at the pons. Functions: Breathing Heart Rate Swallowing Reflexes to seeing and hearing (Startle Response). Controls sweating, blood pressure, digestion, temperature (Autonomic Nervous System). Affects level of alertness.

Ability to sleep. Sense of balance (Vestibular Function). Grey matter closely packed neuron cell bodies (making up the cerebral cortex) form the grey matter of the brain. The grey matter includes regions of the brain involved in muscle control, sensory perceptions, such as seeing and hearing, memory, emotions and speech. White matter neuronal tissue containing mainly long, myelinated axons, is known as white matter or the diencephalon. It makes up the cerebrum. The color comes from the myelin.

The nuclei of the white matter are involved in the relay of sensory information from the rest of the body to the cerebral cortex, as well as in the regulation of autonomic (unconscious) functions such as body temperature, heart rate and blood pressure. Certain nuclei within the white matter are involved in the expression of emotions, the release of hormones from the pituitary gland, and in the regulation of food and water intake. These nuclei are generally considered part of the limbic system. Brain stem: 3 parts Lower animals

have only a medulla. The brain stem controls the reflexes and automatic functions (heart rate, blood pressure), limb movements and visceral functions (digestion,


Corpus callosum Cerebellum Pituitary gland Pons Medulla 1. Spinal cord Frontal Temporal Occipital Parietal

Put answers on back of fill-in page 6. 7. 8. 2. 3. 9. 4. 5.

10. 12 Cranial Nerves Fissure: any cleft or groove, normal or otherwise, especially a deep fold in the cerebral cortex involving its entire thickness. Brains

Wild pig, dolphin, human Chimpanzee Sheep Brain Dissection Guide Dura mater Superior ID After splitting the cerebral hemispheres Part 1: Sheep brain dissection v=y7gEWzPqm94

Ventral side of the brain Part 2: Brain dissection v=jr3qSaUzc6Q Here's the cerebellum pushed downward to expose the superior and inferior colliculi and pineal gland The Superior colliculus (2 parts)

and the inferior colliculus (2 parts) make up the corpora quadrigemina. They are the reflex centers involving hearing and vision. The Nerves The largest nerve in

the body is the sciatic and it splits into the common tibial and fibular nerves that run down each leg. How the messages travel PNS

As part of the Peripheral Nervous System, nerves reach from your brain to your face, ears, eyes, nose, and spinal cord... and from the spinal cord to the rest of your body. Motor neurons (motoneurons) carry signals from the central nervous system to the outer parts (muscles, skin, glands) of your body. Sensory neurons carry signals from the outer parts of your body

(periphery) into the central nervous system. Receptors sense the environment (chemicals, light, sound, touch) and encode this information into electrochemical messages that are transmitted by sensory neurons. Interneurons connect various neurons within the brain and spinal cord. Reflex Pathways

The simplest type of neural pathway is a monosynaptic (single connection) reflex pathway, like the knee-jerk reflex. 1. When the doctor taps the right spot on your knee with a rubber hammer, receptors send a signal into the spinal cord through a sensory neuron.

2. The sensory neuron passes the message to a motor neuron that controls your leg muscles. Nerve impulses travel down the motor neuron and stimulate the appropriate leg muscle to contract. 3. The response is a muscular jerk that happens quickly and does not involve your brain.

Humans have lots of hard-wired reflexes like this, but as tasks become more complex, the pathway "circuitry" gets more complicated and the brain gets involved. Revisiting the Knee-Jerk Response What is the stimulus? The hammer hits the tendon. The muscle contracts, causing the foot to jerk upward. What is the response? The muscle contracts, causing

the foot to jerk upward. How is the Hammer Tap Detected? The muscles in your leg have stretch receptors. They react to a change in length of the muscle. When the hammer hits the tendon at the knee, it makes a muscle in the front of your thigh longer (stretches it).

That stimulates the stretch receptors in that muscle. Other Reflexes: Stimulus Response An insect flying towards your eye Blinking

The aroma of your favorite food Salivation A bright light shining in your eye Pupils get smaller A nasty odor Nausea Whats a Reflex?

You need to detect a change in the environment (a stimulus) and react to the change (a response) in a way that maintains homeostasis. When you do this without thinking, it is called a reflex. How is a Stimulus Detected? Some cells are specialized to react to a specific stimulus. These are called receptors (they receive a stimulus). The receptor cells of your

eyes are stimulated by light. The Response When the receptor is stimulated, it sends a message to a part of your body that effects the correct response. This is called the effector. Reflex arc How the Message Travels From the

Receptor to the Effector. A sensory neuron carries the message from the receptor to the central nervous system (the spinal cord and brain). A motor neuron carries the message from the central nervous system to the effector. This is a reflex arc. Motor (efferent) Neurons Is divided into two groups: 1. Autonomic system The ANS In most situations, we

are unaware of the workings of the ANS because it functions in an involuntary, reflexive manner. 2. Somatic system (back to this in a moment) Name the Neurons Neuron 2 ? Sensory (Afferent) Neuron Name the Neurons Neuron 3 ?

Interneuron Name the Neurons Neuron 4 ? Motor (Efferent) Neuron The ANS is most important in two situations: 1.In emergencies that cause stress and require us to "fight" or take "flight" (run away) 2.In non-emergencies that allow us to "rest" & "digest."

The ANS is divided into three parts: 1. The sympathetic nervous system 2. The parasympathetic nervous system 3. The enteric nervous system (is a meshwork of nerve fibers that innervate the viscera (gastrointestinal tract, pancreas, and gall bladder). . ANS Sympathetic:

These are "Fight or Flight" responses. In these types of situations, your sympathetic nervous system is called into action - it uses energy your blood pressure increases, your heart beats faster, and digestion slows down. Parasympathetic This calls for "Rest and

Digest" responses. Now is the time for the parasympathetic nervous to work to save energy your blood pressure decreases, your heart beats slower, and digestion can start. The Autonomic Nervous System Structure

Sympathetic Stimulation Parasympathetic Stimulation Iris (eye muscle) Pupil dilation Pupil constriction Salivary Glands

Saliva production reduced Saliva production increased Oral/Nasal Mucosa Mucus production reduced Mucus production increased Heart

Heart rate and force increased Heart rate and force decreased Lung Bronchial muscle relaxed Bronchial muscle contracted

Stomach Peristalsis reduced Gastric juice secreted; motility increased Small Intestine Motility reduced Digestion increased

Large Intestine Motility reduced Secretions and motility increased Liver Increased conversion of glycogen to glucose

Kidney Decreased urine secretion Adrenal medulla Norepinephrine and epinephrine secreted Bladder Wall relaxed

Sphincter closed Increased urine secretion Wall contracted Sphincter relaxed The inner part, the adrenal medulla, produces catecholamines, such as epinephrine. Also called adrenaline,

epinephrine increases blood pressure and heart rate when the body experiences stress. These hormones are produced in response to stressors such as fright, anger, caffeine, or low blood sugar. (Epinephrine injections are often used to counteract a severe allergic reaction.)

Detailed epinephrine action :Fight or Flight: watch? v=ejq99wLEMTw&feature= related Flight or Flight Response Video v=4g25d7_Afmc&feature=related (from Discovery Channel: 6 min.) Adrenaline Rush: Standing on a cliff: http:// v=DplhL6mJhcQ&feature=related Adrenaline Rush: Shark cage: v=50dVhd4dmp8&feature=fvwrel Back to The Somatic Nervous System Somatic Nervous System The somatic nervous system consists of

peripheral nerve fibers that send sensory information to the central nervous system AND motor nerve fibers that project to skeletal muscle. The picture shows the somatic motor system. The cell body is located in either the brain or spinal cord and projects directly to a skeletal muscle. This very strange creature in the Glasgow Science

Centre is the Homunculus. The different parts of the body are sized according to the amount of nerves present in that part of the body. Alzheimers disease: progressive degenerative

brain disease that results in dementia associated with a shortage of acetylcholine (an important neurotransmitter) and structural changes in brain areas involving cognition and memory. Because nerve cells do not undergo mitosis, new cells can not be generated.

Cerebrovascular accident (CVA): brain dysfunction where blood supply to a region is blocked and vital brain tissues dies as by a blood clot or ruptured blood vessel. This is more

commonly called a stroke. Stroke Test: Talk, Wave, Smile The F.A.S.T. test helps spot symptoms. It stands for: Face. Ask for a smile. Does one side droop? Arms. When raised, does one side drift down? Speech. Can the person repeat a simple sentence? Does he or she have trouble or

slur words? Time. Time is critical. Call 911 immediately if any symptoms are present. Parkinsons Disease Parkinson disease (PD) is characterized by a slowing of voluntary movements, bradykinesia stone face, muscular rigidity and tremor at rest. These abnormalities result from a reduction of neurons that make dopamine.

Multiple sclerosis: when the myelin sheath around the axon deteriorates the electrical current is short circuited. The person may experience visual and speech disturbances and also lose muscle

control. M.S. Tourette Syndrome This syndrome begins in childhood and manifests itself through various forms of tics. These tics include frequent, irregular movements of the head, neck, or shoulders. They also may be more complex motor behaviors such as snorting, sniffing, and involuntary vocalization. As the syndrome progresses repetitive behaviors such

as touching others, obsessive compulsive symptoms, and explosive involuntary cursing can be more common. Aggressive behavior and improper sexual impulses are the rarest and most severe expressions of the syndrome. The cause of Tourette syndrome is not known, but it is believed to have a genetic component. Famous People with Tourettes (OCD) Dan Ackroyd was

diagnosed with tourette's and asperger syndromes at an early age, but the symptoms seem to have Wolfgang Amadeus Mozart disappeared when he was (1756-1791) It has also been documented that he was around 14. The diagnosis hyperactive, suffered from swings, had tics, and of Asperger syndrome did mood loved made-up words. Despite these behaviors, we will not exist in the 1960s, probably never know for certain

when Aykroyd was a whether Mozart had TS. preteen. It involved mostly grunting and physical tics through nervousness. David suffers from OCD and it manifests itself through constant cleanliness and perfection of all that is around him. Anything out of order is enough to cause a conflict and

must be attended to immediately. Examples of this complete order is that everything must be in pairs, if there are three books on a table one must be added, or one must be removed. Only 2% of the population suffer from this strong OCD. Cerebral Edema The brain reacts to severe head trauma by retaining water. As a result, the brain swells.

The pressure grows as the brain presses on the skull. This can be fatal or result in severe brain damage. Famous People with Cerebral Edema Actor Natasha Richardson Video: The Secret Mind 54 min

docid=2661634191857056612# Nervous System Test Complete your study guide to prepare for the test. The test has. 29 multiple choice (2 pts each) 6 labeling neuron (2 points each) 10 fill in the blanks (2 pts each) 6 label parts of the brain

100 points

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