Presentation on theme: "What parts of the body is the Central Nervous System comprised of?"— Presentation transcript:
1What parts of the body is the Central Nervous System comprised of? IFAWhat parts of the body is the Central Nervous System comprised of?
2Anatomy of the Central Nervous System New technology and advances in science have led to a better understanding of the relationship of the brain, biological basis of behavior, and mental disorders
3Student ObjectiveI can identify parts and functions of the Central Nervous System (CNS)
4Cells of the Nervous System The cells are known as Neurons.Neurons- the basic building block of the nervous system that specialize in transmitting information throughout the bodyUnusual shapeNerve fibers extend from body cell (soma)Dendrites- branched fibers that receive neural impulsesAxons- transmits neural messages from cell body towards another neuron
6Two principal divisions of the nervous system Central Nervous System (CNS)Peripheral Nervous System (PNS)
7Central Nervous System (CNS) Brain and spinal cordServe as control center for entire organismIntegrated incoming information and determines appropriate responses
8Peripheral Nervous System Made up of nerves outside of CNSActs a communication lines to and from CNSMade up of sense organs- eyes, ears, taste buds, olfactory receptors, and touch receptors
9Mental Health LinkUnderstanding of mental disorders most often involves understanding the structure and function of the CNS
10The picture above is a representation of what system of the body? IFAThe picture above is a representation of what system of the body?
11Cerebral Cortex Thin outer surface of the forbrain Largely made up of cell bodies which are grayMost highly evolved portion of the brain
12Cerebrum Forebrain The largest most anterior part of the human brain Control motor activities and interprets sensations
13Lobes of the CerebrumFrontalTemporalParietalOccipital
14Frontal Lobe Motor cortex-control skeletal muscles Broca’s speech area-formation of wordsResponsible for personalityDamage can cause a change in personality
15Temporal Lobe Auditory area Language memory and speech capacity Damage can result in aphasiaAphasia: partial or total inability to produce and understand speech as a a result of brain damage cause by injury or disease
16Parietal LobeSensory association area- impulses from skin such as pain and temperature are interpretedArea for estimation of distances, sizes, and shapes
17Occipital Lobe Primary visual area Trauma can result in blindness Lesions can cause visual hallucinations
18IFAThe picture below is of the brain...what lobe of the brain is the area located and what is the area called?
19Pituitary Gland Master Gland Its secretions control timing and amount of hormone secretions by other endocrine glandsThyroidAdrenal GlandsOvariesTestes
20Cerebellum Responsible for coordination of movements Makes movements smoothHelps maintain muscle toneHelps maintain equilibrium
21Pons Visual Pons Forms a bulge on anterior surface of brain stem The link (bridge) that connects various parts of the brainPons Visual
22Medulla Oblongata Most anterior portion of the brain stem Vital centers of medullaCardiac center: control heart rateVasomotor center: helps regulate blood pressureRespiratory center: initiate and regulate breathingCenter for reflex actions: (vomiting, sneezzing, coughing, and swallowing)
23IFAList the four centers of the Medulla Oblongata. Provide a description of each center.
24The Brain Part II Neurophysiology-Chemical Events at the Synapse Each structure and each chemical produced and used by the brain has a specific function. Disease may cause alteration in the function of the brain. An understanding of the chemical events occurring at the synapse is fundamental to biological psychology.Objective:Student will identify the neurotransmitters and name disorders that can result when there is neurotransmitter dysfunction.
25Neurons Nerve cells that make up the brain and peripheral nerves Communicate with each other at the synapsesSynapse is a functional (not physical) contact between to neuronsAbout 100 billion neurons in human brainEach neuron has about 10,00 synaptic contacts with other neurons.
26Parts of a Neuron Cell body or soma Contains the nucleus of the cell (DNA)Soma constitutes “receiving” surface of the neuronIf the soma is damages, a neuron will not recover
27Parts of a Neuron Dendrite Multiple branches come off the coma Branches receive nerve impulses from other neuronsDendrite branching is influences by environment during development, both pre and post natalThe more branches, the more receiving sites for a neuronDendrites are few and sparsely branched in certain conditions such as Downs Syndrome and Fetal Alcohol SyndromeLab animals who have received stimulations as infants shoe more dendritic branching
28Axon Single fiber that is thicker and longer than dendrites Axon may have many branches at it endAxons may be very short (1 micron) to very long (1 meter) depending on their destinations in the nervous systemDamaged neurons may show sprouting of new terminals to fill in spaces vacated by damaged axonsMature neurons may not have an axonAxon terminals in brain may be represented by these organizations
29Myelin Sheath The lipid and protein sheath surrounding the axon Purpose to insulate neuronThe more heavily mylinated the neuron the faster the electrical pulse can travel down the axon to other neuronsMultiple Sclerosis (MS) condition where the myelin of the brain and spinal cord degenerateNerve impulses unable to travel smoothly and efficiently
30The Synapse A dynamic region between neurons consisting of: Axon terminal (carries electrical impulses away from soma)Synaptic cleft (a space between terminal axon and receiving neuron)Dendrite (or adjacent neuron body)REMEMBER that both SOMA and DENDRITES constitutes the RECEIVING surface of a neuronSynapse Graphic
31Neurotransmitters: The Chemical Messengers Chemicals (hormones) that are made in soma and stored in small synaptic vesicles (“packages”) at the tip of the axonAs electrical pulses travel from soma to axon, neurotransmitters are released into synapseNeurotransmitters stick to receptors proteins in neighboring dendrite and trigger nerve impulse that travel down dendrite, across soma, down axon, etc.Our behavior is consequence of millions of cells “talking” to each other via these electrochemical processesNeurotransmitter Graphic
32Inactivation of Neurotransmitters The action of neurotransmitters can be stopped by four different mechanisms:Diffusion: the neurotransmitter drifts away, out of the synaptic cleft where it can no longer act on a receptor.Enzymatic degradation (deactivation): a specific enzyme changes the structure of the neurotransmitter so it is not recognized by the receptor. For example, acetylcholinesterase is the enzyme that breaks acetylcholine into choline and acetate.Neurotransmitter Graphic
33Inactivation of Neurotransmitters Glial cells: astrocytes remove neurotransmitters from the synaptic cleftReuptake: the whole neurotransmitter molecule is taken back into the axon terminal that released it. This is a common way the action of norepinephrine, dopamine and serotonin is stopped...these neurotransmitters are removed from the synaptic cleft so they cannot bind to receptors
34Some of the Well Known Neurotransmitters Acetylcholine (Ach)Dopamine (DA)Serotonin and NorepinephrineGamma Aminobutyric Acid (GABA)\Endorphines (“endegenous morphine)
35Acetylcholine (Ach)Contributes to movement, learning, memory processes and REM sleepOnly transmitter between motor neurons and voluntary musclesEXCESS: muscle paralysis or convulsions, sometimes deathDEFICIT: memory impairment (Alzheimer’s disease)
36Dopamine (DA) Used by neurons control voluntary movement Also used by neurons that are important for learning, attention, thought, and emotionEXCESS: irrational thought, delusion, and/or hallucinations (Schizophrenia)DEFICIT: tremors, muscular rigidity (Parkinson’s disease)
37Serotonin and Norepinephrine Serotonin play prominent role in regulation of mood, sleep impulsivity, aggression, and appetite.Norepinephrine plays role in eating, sleep, and moodLower level of activity in serotonin and norephinephrine is related to depressionDEFICIT serotonin: may lead to increased aggressive behavior and suicideSome antidepressants drugs act to block reuptake of serotonin or norepinephrine
38What is the synapse composed of? IFAWhat is the synapse composed of?
39Gamma-Aminobutyric Acid (GABA) i. Appears to have inhibitory effects at synapsesii. contributes to regulation of anxietyiii. lower levels of activity related to anxietyiv. antianxiety drugs (tranquilizers such as Valium) facilitate GABA synapses and thereby reduce anxietyv. abnormality in GABA neurons may cause epilepsy
40Endorphins (“endogenous morphine”) opiate-like substances produced in the bodyprovide relief from pain and produce feelings of pleasure and well-beingdrugs such as opium, morphine, and heroin bind with receptors for endorphinsendorphins may explain “runners-high” experienced by long-distance runners
41Imaging of the Brain I. Key Terms A. neuro – root for brain and/or nervous systemB. imaging – procedure which records a picture or “image” of a body partC. tome – Greek word that means “slice” sometimes referred to as a “cut” of body tissuea. in neuroimaging, tome refers to cross-sectional images that demonstrate multiple “slices” of human anatomyb. orientation of cross-sectional images depends on the body plane along which the image was recordedD. –graphy – suffix that means a process of recording (an image)
42Imaging of the BrainII. Body Planes – imaginary planes that pass through the body dividing it into sections; these planes provide the orientation for cross-sectional images in neuroimagingA. transverse plane – imaginary plane that cuts across the body or body part and divides body or its part into upper and lower parts.B. sagittal plane – imaginary plane that cuts the body into right and left sectionsa. midsagittal plane (also called median plane) – imaginary plane that cuts body into equal right and left halvesC. coronal plane (also called frontal plane) – imaginary plane that divides the body or its parts into front and back sections
45Traditional Types of Neuroimaging A. Skull Radiograph (takes about 5 to 10 minutes)a. description: one-dimensional x-ray of skulli. generally requires at least three separate x-ray images from different angles to better determine tissue abnormality1. image from the front (AP x-ray)2. image from the side (lateral x-ray)3. image with head turned 45 degrees (oblique x-ray)
46Skull Radiograph: Advantages/Disadvantages b. advantages:i. relative inexpensiveii. fastiii. demonstrates bony structures and fracturesc. disadvantages:i. radiographic projections are one-dimensional and cannot accurately demonstrate depth and location of lesionii. does not image soft-tissue as well as bone
48Traditional Types of Neuroimaging Cerebral Angiography (takes about 60+ minutes)a. description: traditional skull radiographs taken during injection of radiopaque contrast medium (“dye”) into the carotid arteriesi. visualization of blood flow via the carotid arteries to the brainii. helps diagnose patency of vessels, intracranial aneurysms, & tumor masses, which are shown by displacement of normal vessels
49Cerebral Angiography: Disadvantages/Advantages i. uses bolus of iodine-based dye for visualization of vessels1. may produce allergic reaction in some patients2. could dislodge vascular plaque and cause a stroke
52Neuroimaging of the Late 20th-Century Computerized Axial Tomography –CAT scan (also called CT Scan) (takes 10 to 30 minutes)c. description: involves passing a narrow beam of traditional x-rays through brain of a person lying in a large, donut-shaped x-ray machine called a scanner; provides transverse slices of the headi. beam of x-rays sent out by x-ray tube that rotates around patient’s headii. whole series of x-rays are taken at every angle around the head and then combined in a computer to reconstruct an image of transaxial slice of the head
53Computerized Axial Tomography –CAT scan: Disadvantages/Advantages i. imaging method of choice for examining skull fracturesii. one of the least expensive modalities (other than skull x-rays)e. disadvantages:i. difficult to see brain tissue, therefore, does not serve as specific test for mental disordersii. sometimes dye (called contrast media) must be given as a shot in a vein to help get a clear picture; some people are allergic to this dyeiii. underestimation of brain atrophyiv. inability to image in sagittal and coronal planesv. one CT scan delivers radiation equivalent to many traditional x-rays (this limits the total number of scans that can be performed safely within an individual)
55Magnetic Resonance Imaging (MRI) (takes 30 to 90 minutes) a. description: uses magnetic fields and radio waves to obtain a mathematically reconstructed imageb. how it works:i. certain nuclei in the body are magnetic (those having odd numbers of protons or neutrons)ii. when under the influence of a magnetic field, those nuclei oscillate and reemit radio waves that are picked up by MRI receiver and sent to a computeriii. radio waves are then reconstructed by the computer into an image of the brain
56Magnetic Resonance Imaging (MRI) advantages:i. allows for clear distinctions between cerebrospinal fluid and gray and white matterii. can show minor brain injuries and close-up pictures of base of brainiii. intrinsically 3-dimensional, acquiring multiple images in any plane (transverse, sagittal, and/or coronal)iv. does not involve radiationd. disadvantages:i. noisy (patient ‘s usually given pair of headphones or earplugsii. must lie flat on back inside small “tunnel” of scanner (makes many patients feel claustrophobic)iii. must remove all metal objects & jewelryiv. tests often take a long time (30 to 90 minutes)v. more expensive than CT scans
58Positron Emission Tomography (PET) & Single Photon Emission Computed Tomography (SPECT) a. description: both are noninvasive imaging techniques that scan radioactive material that was injected into a peripheral vessel of the patientb. advantages:i. unlike conventional radiography which demonstrates the structure (anatomy) of organs, PET & SPECT are able to measure particular aspects of human physiology (which is determined from scanner’s measurement of neurotransmitter radioactivity)ii. unlike other studies that use toxic contrast medium (“dye”) to visualize vessels, the small amount of radioactive pharmaceuticals used in PET & SPECT studies are similar to body’s own biochemical constituentsc. note that SPECT studies are much more cost effective than PET exams
60Clinical Applications of PET & SPECT Alzheimer’s Disease and Dementiaa. SPECT studies have shown decreased size of hippocampus and metabolic disturbances in early stages of Alzheimer’sB. Mood Disordersa. SPECT & PET studies consistently found reduced global cerebral blood flow—particularly in unipolar patientsi. decreased activity in prefrontal cortex seen in depressed patientsC. Schizophreniaa. PET studies demonstrate a decrease of activity in frontal lobe and an increase of activity in the subcortical regions
61Clinical Applications of PET & SPECT Anxiety Disordersa. panic attacks: PET scans demonstrate area of hyperactivity in right parahippocampal gyrusb. general anxiety disorder: PET studies show increase in glucose metabolism in thalamusc. obsessive-compulsive disorder: SPECT studies show increased metabolic activity in frontal lobes and basal gangliaE. Personality and Eating Disordersa. bulimia: PET images show cortical asymmetry in metabolic rate for glucoseb. schizotypal personality disorder: abnormalities found in frontal and temporal