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Wilfrid Laurier University
Bruce Mc Kay

Bio supplemental text notes Chapter 3: anatomy of the nervous system General Layout of the Nervous System  Central Nervous System o Skull and spine  Peripheral nervous system o Outside skull and spine  Somatic nervous system  Composed of afferent nerves that carry sensory information from the skin, skeletal muscles joints, eyes, ears  Efferent nerves that carry motor signals from the central nervous system to the skeletal muscles  Autonomic nervous system  Regulates internal environment  Composed of afferent nerves that carry sensory information from internal organs to the CNS  Efferent nerves that carry motor signals from the CNS to internal organs o Afferent(ADVANCE, APPROACH, ARRIVE) goes toward CNS o Efferent Nerves  Sympathetic: autonomic motor nerves that project from the CNS in the lumbar(small of the back) and thoracic(chest area) regions of spinal cord  Parasympathetic: autonomic motor nerves that project from the brain and sacral(lower back) region of the spinal cord o sympathetic and parasympathetic neurons project from the CNS and go PART of the way to the target organs before they SYNAPSE on other neurons that carry the signals the rest of the way. o Sympathetic synapse on second-stage neurons at a large distance, para. Synapse on second-stage neurons close up. 1. The sympathetic nerves stimulate, organize, and mobilize energy resources in threatening situations, whereas parasympathetic nerves act to conserve energy 2. Each autonomic target organ receives opposing sympathetic and parasympathetic input, and its activity is thus controlled by relative leves of sympathetic and parasympathetic activity 3. Sympathetic changes are indicative of arousal, whereas parasympathetic changes are indicative of relaxation.  Cranial Nerves o 12 pairs that project from the brain o numbered in sequence from the front to back o purely sensory nerves(olfactory, optic), longest cranial nerve(vagus) is sensory and motor. o Disruptions of particular cranial nerve functions provide excellent clues about the location and extent of tumors and other kinds of brain pathology.  Meninges, Ventricles, and cerebrospinal fluid o The 3 meninges protect the brain and spinal cord  Outer meninx: a tough membrane called the dura mater. o Inside the dura mater is the arachnoid membrane(weblike)  Beneath the arachnid membrane is the subarachnoid space(contains large blood vessels and CSfluid)  Innermost meninx, pia mater (adheres to the surface of the CNS)  Cerebrospinal fluid also protects the brain and spinal cord, it fills the subarachnoid space, the central canal of the spinal cord, and the cerebral ventricles of the brain o Central canal: small central channel that runs the length of the spinal cord o Cerebral ventricles: 4 large internal chambers of the brain  2 Lateral ventricles, the 3 ventricle and the 4 ventricle. o Subarachnoid space, central canal and cerebral ventricles are interconnected by a series of openings and thus form a single reservoir. o Fluid supports and cushions the brain, those missing some fluid experience headaches and severe pain. o Produced by the choroid plexuses: networks of capillaries that protrude into the ventricles from the pia mater o Excess fluid absorbed by the dural sinuses, into the jugular veins. o Hydrocephalus: a tumor near the cerebral aqueduct, creates a build up of fluid in the venticles and causes the brain to expand  Blood-Brain Barrier o this barrier is a consequence of the special structure of cerebral blood vessels o cells of the blood vessel walls are tightly packed, thus forming a barrier to the passage of many moleculesparticularly proteins and other large molecules. o The degree to which drugs affect the brain depends on how easily it can penetrate the barrier. Chapter 5: the research methods of biopsychology Methods of visualizing and stimulating the living human brain  X-rays were used, but they’re relatively useless. o X-ray beam passed through an object then onto a photographic plate. X-ray is effective in characterizing internal structures that differ substantially from their surroundings in the degree to which they absorb x-rays.  Contrast x-rays o Involve injecting into one compartment of the body a substance that absorbs x-rays either less than or more than the surrounding tissue. The injected substance heightens the contrast between the compartment and the surrounding tissue during x-ray photography.  Cerebral angiography: uses the infusion of a radio-opaque dye into a cerebral artery to visualize the cerebral circulatory system during x-ray photography. Useful for locating vascular damage, and the location of displaced vessels (could indicate a tumor)  X-ray computer tomography o Computer assisted x-ray procedure that can be used to visualize the brain and other internal structures of the living body. An x-ray tube projects an x-ray beam through the head to an x-ray detector mounted on the other side. The tube and detector rotate around the head of the patient at one level of the brain, taking images as they rotate. The information of each pic is combined to generate a CT scan of a horizontal section. Scans of 8 or more levels are combined to create a 3D image.  Magnetic Resonance imaging o High-resolution images are constructed from the measurement of waves that hydrogen atoms emit when they are activated by radio frequency waves in a magnetic field. Provides high spatial resolution, and images in 3D.  Positron Emission Tomography o First to provide images of brain activity rather than structure. o 2Deoxyglucose is injected into the carotid artery, bc its similar to glucose, the 2deoxyglucose is rapidly taken up by active cells. However, it cannot be metabolized SO the areas with glucose are the areas being activated.  Functional MRI o Produces images representing the increase in oxygen flow in the blood to active areas of the brain. o Possible because active areas in the brain take up more oxygen than they need for their energy requirements, thus oxygenated blood accumulates in active areas in the brain. Second, oxygenated blood has magnetic properties. o BOLD signal: blood oxygen level dependent signal o Advantages over PET  Nothing is injected  Provides structural AND functional info in one image  Better spatial resolution  Can take 3D images over the entire brain  Magnetoencephalography (MEG) o Measures changes in magnetic fields on the surface of the scalp tat are produced by changes in underlying patterns of neural activity, o Advantage over fMRI  Temporal resolutioncan record fast changes in neural activity  Trans-cranial Magnetic Stimulation o Technique for affecting the activity in an area of the cortex by creating a magnetic field under a coil positioned next to the skull o Temporarily turns off part of the brain while the effects of the disruption on cognition and behavior are assessed. Chapter 6: The Visual System Light Enters the Eye and Reaches the Retina  If there is no light, there is no vision. o Animals cant actually see in the dark  Light behaves as particles and as waves  Light: waves of electromagnetic energy that are between 380 and 760 nanometers in length.  Wavelength: plays an important role in the perception of colour  Intensity: plays an important role in the perception of brightness  The pupil and the Lens o The amount of light reaching the retinas is regulated by the donut shaped bands of contractile tissue, the irises (eye colour) o Light enters the eye through the pupil (hole in the iris). The adjustment of the pupil size in response to changes in illumination represents a compromise between sensitivity (ability to detect dimly lit objects) and acuity (ability to see details) o When the level of illumination is high, the pupils constrict  Image on the retina is sharper and there is a greater depth of focus o When illumination is low, the pupils dilate to let in more light, thereby sacrificing acuity and depth of focus o Behind each pupil is a lens (focuses incoming light on the retina)  When we look at something near, the tension on the ligaments holding each lens in place is adjusted by the ciliary muscles and the lens assumes its natural cylindrical shape.  The ability for the lens to refract (bend) light and thus brings close objects into sharp focus.  When we look at something distant, the lens flattens. The process of adjusting the configuration of the lenses to bring images into focus on the retina is called accommodation  Eye position and binocular disparity o Vertebrates have two eyes because vertebrates have two sides  By having an eye on each side, they can see in every direction o Humans have eyes on the front so that what is in front can be viewed through both eyes simultaneously  Important basis to create 3D perceptions o Your eyes are coordinated so that each point in your visual world is projected to corresponding points in your two retinas  Your eyes must converge(turn inward). Convergence happens the most when your eyes are inspecting things that are close.  Binocular disp
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