2. Central nervous system (CNS) = brain + spinal cord Peripheral nervous system = nerves running to and from to and from the CNS to all parts of the body
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6. receptor sensory neurones motor neurones effector Basic plan of a nervous system The functional unit of the nervous system is the neurone . stimulus response relay neurones in central nervous system muscle or gland change in the environment of the receptor generates nerve impulses
18. Many neurones also have a myelin sheath around the axon – called myelinated neurones. It is formed by specialised cells called Schwann cells which wrap around the axon
24. The cell membranes are compressed together to form a tightly packed layer of myelin which is rich in a particular type of membrane lipid. It acts as an insulator to prevent the movement of ions across the cell membrane and so acts as an insulator which speeds up the speed of transmission of nerve impulses nucleus of Schwann cell cytoplasm of axon Saltatory conduction animation http://www.blackwellpublishing.com/matthews/actionp.html
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29. Checkpoint 8.1 Compare the structure and location of motor, sensory and relay neurones Motor Relay Sensory Structure Cell body, short dendrites, long axon Cell body, short dendrites, short axon Cell body, long dendrites, short axon Location of cell body Cell body + dendrites in CNS Axon outside CNS Cell body etc inside CNC Cell body and dendrites outside CNS, axon inside CNS Dendrites Dendrites synapse with effectors Dendrites synapse with other neurones Dendrites synapse with receptors Axons End in effector Axons synapse with other neurones Axons synapse with relay and other neurones in CNS Function Transmit impulses from CNS to effector Connect sensory and motor neurones to form nerve circuits Transmit impulses from receptors to CNS
50. Describe the nerve pathways involved if the hand was picking up a hot dinner plate but the person did not want to drop the plate. Impulses will travel along the basic reflex arc…plus Receptor sensory neurone CNS neurone to sensory area of brain brain ‘ feels’ hot/pain cerebrum/decision made not to drop plate impulses to motor area impulses from brain to synapse of relay neurone with motor neurone inhibition of synapse biceps does not contract + forearm muscles contract to keep hold of plate
82. Brain anatomy. Computer artwork of a human brain, seen from the side. The front of the brain is at left. From to top to centre is one of the hemispheres of the cerebrum, which is responsible for conscious thought, emotion and voluntary movement. Branching from the centre of the brain towards the front are the olfactory bulbs. At bottom right is the brainstem, which consists of the medulla oblongata, pons and midbrain. It controls automatic functions, sleep and arousal and relays messages from the brain to the spinal cord. At right is the cerebellum, which controls muscle coordination and balance.
84. Sensory homunculus: "This model shows what a man's body would look like if each part grew in proportion to the area of the cortex of the brain concerned with its sensory perception." [ music | X-mal Deutchland -- Incubus Succubus II ]
85. Motor homunculus: "This model shows what a man's body would look like if each part grew in proportion to the area of the cortex of the brain concerned with its movement."
104. Colour vision deficiency, sometimes inaccurately called colour blindness, occurs when the cells in the retina of the eye which respond to light (cones) are abnormal or not working as well as they should. The three types of cones are commonly known as red, blue and green, although they actually differ in their ability to recognise high, medium and low wavelength light.When they do not pick up or relay the proper colour signals to the brain, colour deficient vision results. Approximately 8% of men and 1% of women have some form of colour vision deficiency. Colour vision deficieny or ‘colour blindness’
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106. Color blindness has several forms. Trichromats are the people who have full color vision. Dichromats are the people who can see only two of three primary colors of light (red, green, blue). Dichomacy has several forms. Achromatopsia is the inability to see any colors which may be called the actual color blindness. These people see life in monochrome, or greys.
107. The world . How the world looks to a person with a red/green color deficit (deuteranopia). How the world looks to a person with a blue/yellow color deficit (tritanopia).
108. Some colorful hats As seen by a person with deuteranopia As seen by a person with protanopia, another form of red/green deficit
109. People with color deficiencies may have difficulty distinguishing certain colors (e.g., a red/green color deficiency means that reds and greens are more difficult to distinguish). But as this photo demonstrates, many other colors are just as distinguishable to a person with a color deficiency as to someone with normal color vision. Poppies and cyclamen Protanope Tritanope.
110. This is an Ishihara plate commonly used to check for red/green color blindness This is what a red/green color-blind person might see. Note that the digit (3) is practically invisible.
111. normal color vision Same colors seen by color blind people who have absence of red sensitivity and red weakness absence of green sensitivity and green weakness absence of blue sensitivity
