The Nervous System

Nervous system

Structure

The Neuron

Neuron Cell body

Neuron Cell Body Nissl Bodies A unique structure to neurons Large granular bodies, clusters of rough ER Gives the cell body its gray color (gray matter) Synthesize and release proteins

Classification of Neurons

Functional Classification of Neurons

Neurotransmission depends on action potential: Short lasting electrical event on the plasma membrane of neurons.

Neuroglial Cell

Divisions of the Nervous system

Cerebrum: Frontal lobe Primary motor area: conscious movement of all skeletal muscles Higher intellectual reasoning Parietal lobe: Somatic sensory cortex area: Touch, pain, temperature..etc) Temporal lobe: Auditory area, olfactory area Occipital lobe: Visual area

Thalamus: Relay station for sensory impulses Cerebrum  Sensory signals  thalamus  brain stem  spinal cord  PNS Hypothalamus: Regulates body temp, water balance, metabolism (TSH) Stress management: by adrenocorticotropic hormone (ACTH)  adrenal glands Controls pituitary gland: GH, prolactin, oxytocin…etc. Important part of the “limbic system” or emotional visceral brain (thirst, appetite, pleasure, pain..etc) Influences controls of the medulla oblongata Epithalamus: Contains pineal gland  melatonin (sleep hormone) Choroid plexux  forms CSF

Brain Stem: Midbrain Bulges in front called cerebral peduncles: coordinate fine motor movements (e.g. grasping an object between a thumb and a finger) Dorsally: protrusions called corpora- quadrigemina: involved in vision and hearing Pons Involved in the control of breathing Medulla oblongata Cardioregulatory centers (heartbeat, blood pressure, vasoconstriction…) Breathing, swallowing, vomiting

Cerebellum: Located under the cerebrum Functions: Controls balance and movement coordination By receiving information from the body and sending information to the body

Spinal Cord: Receives signals from the brain Passes signals to the PNS (which take them to the rest of the body)

Somatic nervous system Autonomic nervous system