lecture_Ch04_2[1]

lecture_Ch04_2[1] - Drugs and Behavior Drugs Homeostatic...

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Unformatted text preview: Drugs and Behavior Drugs Homeostatic Systems and Drugs – part II PSY 291 Ipsilateral – located on the same side of the body body Contralateral – located Contralateral on the opposite side of the body of Basic Features of the Nervous System Basic rain Slices and Planes Cross Section or Frontal Section Transverse section at right angles to the neuraxis. Horizontal Section Section made through the brain parallel to the ground. Sagittal Section Section parallel to neuraxis and perpendicular to the ground. Midsagittal Plane – special type of sagittal section through Midsagittal the corpus callosum separating the hemispheres. the Planes of Section Planes Directions in the Nervous System Directions nterior edial audal idsagittal Plane ontralateral euraxis ross Section osterior orsal ostral rontal Section agittal Section Transmit pain or subconscious sensation from the body organs or blood vessels to the CNS Transmit sensation from the body to the CNS: a. exteroceptive sensation (pain, temp., touch and pressure) b. proprioceptive sensation (from muscles, joints and tendons) Sensory neurons Autonomic Internal Nervous Environment System Motor neurons Transmit impulses from CNS to smooth (involuntary) muscles and glands. Sensory neurons CNS Somatic Nervous System External Environment Motor neurons Transmit impulses from CNS to skeletal (voluntary) muscles. Gray matter – areas of the CNS with predominance of cell bodies and dendrites. White matter – areas of the CNS with predominance of axons. Cortex – area where gray matter forms a surface covering on some part of the CNS. Nucleus – collection of neuronal cell bodies (gray matter) located deep inside the brain. Ganglion – collection of neuronal cell bodies located outside CNS. Subcortical region – region located within the brain, beneath the cortical surface. Fissure – a major groove in the surface of the brain, larger than a sulcus. Sulcus (sulci) – a groove in the surface of the cerebral hemisphere, smaller than a fissure. Gyrus (gyri) – convolution of the cortex separated by sulci or fissures. Nerve fiber – an axon and surrounding connective tissue. Tract – bundle of nerve fibers (axons) that connect nuclei, in CNS. Forms the white matter. Nerve – bundle of nerve fibers, the layers of connective tissue holding them together, and the blood vessels serving them, in PNS. Brain Spinal cord Blood Brain Barrier (BBB) Blood Paul Ehrlich The Blood-Brain Barrier The a semipermeable (selective permeability semipermeable depending on lipid solubility) 2-way barrier between the CNS and circulatory system, produced by the endothelial cells in the capillary walls. capillary provides mechanism to preserve homeostasis provides of the CNS by promoting entry of needed substances and by excluding or removing unwanted substances. unwanted breaks down unter certain conditions breaks (infections, stroke, brain tumors, etc.). (infections, BBB (cont) BBB Problem: Not all medications can pass the Problem: BBB BBB Solution: Administer precursor peripherally (Parkinson’s Administer disease—L-dopa) disease—L-dopa) Temporarily inactivate BBB (sugary substance Temporarily can temporarily dehydrate BBB cells, opening junctions—experimental) junctions—experimental) Relative ease of crossing the BBB BBB All crosses nicotine, diazepam (valium) nicotine, ethanol ethanol caffeine caffeine heroin heroin glucose glucose L-Dopa L-Dopa morphine morphine dopamine dopamine potassium (K+) potassium None crosses Cerebrospinal Fluid Cerebrospinal Brain floats in cerebrospinal fluid (CSF) Brain (CSF) CSF reduces net weight from 1400 g --> 80 g CSF reduces the shock to the CNS caused by CSF sudden movements. sudden CSF fills also four brain ventricles Total volume of CSF is ~ 125ml Central Nervous System Central CNS Brain Spinal cord CNS 1. receives information from PNS (sensory input) 1. 2. evaluates information 3. regulates muscle and organ activity via PNS 3. (response output) Central Nervous System Central Reticular activating system Receives input from all the sensory systems and Receives cerebral cortex cerebral Controls the brain’s state of arousal (sleep vs. Controls awake) awake) Basal ganglia Controls motor activity Limbic system Regulates emotional activities, memory, hormone Regulates activity and reproductive behaviors activity Central Nervous System (continued) (continued) The cerebral cortex Helps interpret, process, and respond to Helps information information Selects appropriate behavior and suppresses Selects inappropriate behavior inappropriate Associative cortex: memory storage, language, Associative abstract thinking, learning abstract The hypothalamus Controls release of hormones (endocrine Controls system) and basic body functions system) Central Nervous System Structure Structure Transmit pain or subconscious sensation from the body organs or blood vessels to the CNS Transmit sensation from the body to the CNS: a. exteroceptive sensation (pain, temp., touch and pressure) b. proprioceptive sensation (from muscles, joints and tendons) Sensory neurons Autonomic Internal Nervous Environment System Motor neurons Transmit impulses from CNS to smooth (involuntary) muscles and glands. Sensory neurons CNS Somatic Nervous System External Environment Motor neurons Transmit impulses from CNS to skeletal (voluntary) muscles. Peripheral Nervous System Peripheral INPUT to CNS: sensory information INPUT including: pain, temperature, & pressure including: OUTPUT from CNS: regulate muscle and OUTPUT organ activity to maintain homeostasis maintain PNS Output PNS Two types : SOMATIC: control of voluntary muscles AUTONOMIC: involuntary control of organ AUTONOMIC: and gland activity and Effect of nerve damage: SOMATIC: paralysis and muscle atrophy AUTONOMIC: disturbance of homeostasis Autonomic Nervous System Autonomic Sympathetic and parasympathetic systems These systems work in an antagonistic fashion These to control unconscious, visceral functions such as breathing and cardiovascular activity Sympathetic Fight or flight. Parasympathetic Rest and regenerate. Autonomic Nervous System Structure Structure RED BLUE Parasympathetic versus Sympathetic nervous system ...
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