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Chapter 2: Neuroscience: The Biologicals Perspective, References: 1)…

- - - - The organ located within the skull that is responsible for cognition, mental processes, and control of the body and its functions. It is the location of perception, ideas, thoughts, conscious movement, and unconscious body functions like heart rate and digestion
    - - The cylindrical bundle of nerve fibers and associated tissue is enclosed in the spine and connects nearly all parts of the body to the brain, with which it forms the central nervous system.
    - - Cells of nervous system
        
        Neuron:
        specialized cells that transmit chemical and electrical signals to facilitate communication between the brain and the body
        
        Motor neuron (efferent neuron):
        a neuron that carries messages from the
        central nervous system to the muscles of the body.
        
        Interneuron: A neuron found in the center of the spinal cord that receives information from the sensory neurons and sends commands to the muscles through the motor neurons
        
        sensory neurons(afferent neuron):
        a neuron that carries information from the senses to the central nervous system
        
        Neuroglia cells:
        Non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the central (CNS) and peripheral nervous systems (PNS )
        
        Neuroglia cells of CNS
        
        Astrocytes:
        :check: they support and brace the neurons and anchor them to their nutrient supply lines.
        :check: play an important role in making exchanges between capillaries and neurons.
        :check: regulate the external chemical environment of neurons by removing excess ions and recycling neurotransmitters released during synaptic transmission.
        
        Microglial cells:
        :check: can transform into a special type of macrophage that can clear up the neuronal debris.
        :check: They are also able to monitor the health of neurons by detecting injuries to the neuron.
        
        Ependymal cells:
        :check: Line the ventricles of the CNS, forming a permeable barrier between the cerebrospinal fluid (CSF) and underlying cells
        :check: Aid in the circulation of CSF through cilial beat
        
        Oligodendrocytes: :check: They line up along the nerve fibers in the CNS and wrap their process tightly around the fibers producing the insulating myelin sheath
        
        Neuroglia cells of PNS
        
        Schwann cells: :check: Providing myelination to axons in the PNS. :check: They also have phagocytotic activity and clear cellular debris that allows for regrowth of PNS neurons
        
        Satellite cells: :check: surround neurons’ sensory ganglia in the ANS :check: assist in regulating the external chemical environment
        :check: very sensitive to injury and may exacerbate pathological pain.
  - - - Parasympathetic: Involved in maintaining homeostasis and also, permits the rest and digest response.
        
        Example:
        1)Food digestion
        2) Dilates blood vessels leading to the GI tract, increasing blood flow.
        3)Constricts the bronchial diameter when the need for oxygen has diminished.
        4)Causes constriction of the pupil and contraction of the ciliary muscle to the lens, allowing for closer vision.
        5)Stimulates salivary gland secretion, and accelerates peristalsis.
        6)Stimulates sexual arousal.
      - Sympathetic: Involved in the fight or flight response
        
        Example:
        1)Slamming on the brakes when the car in front of you suddenly stops.
        2)Inhibits digestion.
        3)Diverts blood flow away from the gastro-intestinal (GI) tract and skin via vasoconstriction.
        4)Blood flow to skeletal muscles and the lungs is enhanced (by as much as 1,200% in the case of skeletal muscles).
        5)Dilates bronchioles of the lung, which allows for greater alveolar oxygen exchange.
        6)Increases heart rate and the contractility of cardiac cells (myocytes), thereby providing a mechanism for the enhanced blood flow to skeletal muscles.
        7)Dilates pupils and relaxes the ciliary muscle to the lens, allowing more light to enter the eye and far vision.
        8)Provides vasodilation for the coronary vessels of the heart.
        9)Constricts all the intestinal sphincters and the urinary sphincter.
        10)Inhibits peristalsis.
        11)Stimulates orgasm.
    - - Sensory neurons(afferent neurons): responsible for carrying information from the body to the CNS
      - Motor neurons(efferent neurons): responsible for carrying information from the brain and spinal cord to muscle fibers throughout the body
- - - - Primary visual cortex
        
        processes visual information from the eyes.
        
        Visual association cortex
        
        identifies and makes sense of visual information.
    - - Somatosensory cortex
        
        area of neurons running down the front of the parietal lobes responsible for processing information from the skin and internal body receptors for touch, temperature, body position, and possibly taste.
    - - Primary auditory cortex
        
        processes auditory information from the ears.
        
        Auditory association cortex
        
        identifies and makes sense of auditory information.
    - - Motor cortex
        
        section of the frontal lobe located at the back, responsible for sending motor commands to the muscles of the somatic nervous system.
- - - - Parasympathetic division Relax the body to conserve and maintain energy.
      - Sympathetic division Stimulate body to expend energy..
- - - - Dendrites Receive message from other neurons.
      - Soma (cell body) Maintain the life of the cell
      - Axon Carries message to other neurons
- - - - If damaged, these impulses slow down
- - - - Allows +ve Na ions to enter the cell
  - - - During action potential, +ve charge ion rush into axon. Changes the electrical charge inside the axon from -ve to +ve. Now, the charge outside become -ve.
        
        Action potential advances as +ve and -ve charges reverse in a moving zone of electrical activity that sweeps down the axon.
        
        After action potential, +ve ions rapidly flow out of axon to quickly restore -ve charge, returns to its resting state.