MIDTERM 2

• Nervous system functions:

  1. Sensory Input
  2. Integration
  3. Motor output
• Neurons:

  1. Cell Body
  2. Dendrites
  3. Axons
• Neurons lack centrioles, so they are unable to reproduce.
• Neuron Classification:

  1. Sensory neurons
  2. Motor efferent neurons
  3. Interneurons
• Sensory (Afferent) Neurons


  Receptors are distal, extend from sensory receptors to the CNS
• Motor (Efferent) Neurons


  Instructions from CNS to peripheral effectors (gland, muscle)
• Interneuron


  Between motor and sensory neurons

  Entirely in CNS
• Neuroglia

  • Not electric excitable
  • about 1/2 volume of the nervous system
  • can reproduce
• Astrocytes

  • Chemical environment homeostasis
  • Blood-brain barrier
  • Brain development
• Ependymal Cells

  • Cerebrospinal fluid production
• Oligodendrocytes & Schwann Cells

  • Myelin sheath production
• Myelin Sheath

  • Axon electrical insulation
  • Increase speed of nerve impulse conduction
• White matter

  • Myelinated brain and spinal regions
• Gray matter

  • Mostly neuronal cell bodies
  • Non-myelinated fibers
• Satellite Cells

  • Structural support
  • Regulate exchange of materials between cells bodies and intestinal fluid
• Neuroglia in the PNS

  • Satellite Cells
  • Schwann Cells
• Neuroglia in the CNS

  • Oligodendrocytes
  • Astrocytes
  • Microglia
  • Ependymal Cells
• Synapse


  A junction where communication occurs between neurons and

  • Neurons
  • Muscles
  • Glands
• Synaptic Communication

  1. Presynaptic neuron
  2. Postsynaptic cell
  3. Synaptic cleft
• Microglia

  • Waste removal
  • Immunity
• Spinal Cord Functions

  • Sensory impulse to brain
  • Motor impulse to effectors
  • Reflexes
• Spinal Cord Protection

  • Vertebrae
  • Meninges
  • Cerebrospinal fluid
• Meninges

  • Dura mater
  • Arachnoid mater
  • Pia mater
• Cerebrospinal fluid

  • Shock absorber
  • Nutrients to CNS
  • Removes waste
• Reflex/Reflex Arc

  • Predictable, automatic response
  • Integrated by the spinal cord
• Reflex Arc Components

  1. Sensory Receptor
  2. Sensory Neuron
  3. Integrating Center
  4. Motor Neuron
  5. Effector
• What is the advantage of a reflex arc?


  Rapid response
• Brain Protections:

  • Cranial Bones
  • Cranial Meninges
  • Cerebrospinal Fluid
• Brainstem

  • Medulla oblongata
  • Pons
  • Midbrain
• Medulla Oblongata

  • Upward extension of spine
  • Anterior to cerebellum
  • Vital signs
  • Cardiac, Respiratory, Vasomotor centers
  • Vomiting, Hiccuping, Swallowing, Sneezing, Coughing
• Pons

  • Superior to medulla oblongata
  • Links brain parts with tracts
  • Respiratory centers
• Diencephalon

  • Thalamus
  • Hypothalamus
  • Epithalamus
• Thalamus

  • Relay station for all sensory impulses towards cerebrum
• Hypothalamus

  • Below thalamus
  • ANS control
  • Hormones
  • Body temp, Hunger, Thirst, Sleep
• Epithalamus

  • Superior, posterior to thalamus
  • Pineal gland: melatonin
• Cerebrum

  • Ridges: gyrus
  • Shallow grooves: sulci
  • Deep grooves: fissures
  • Divded by Central sulcus, Longitudinal fissure, Parieto-occipital sulcus
  • Conscious thought
  • Memory storage, processing
  • Intellect
• Cerebellum

  • Coordination
  • Muscle tone
  • Discerning appropriate movement
  • Posture, equilibrium
  • Sensory info from: Joints, Muscles, Eyes, Ears
  • Fine tunes preprogrammed movement from cerebrum
• Limbic System

  • Emotional Brain
  • Fear, Pain, Pleasure, Affection, Anger
• Autonomic Nervous System

  • Sensory: Organ receptors, keep CNS informed
  • Motor: Smooth, Cardiac muscle, glands, parasympathetic, sympathetic
• Parasympathetic Nervous System

  • Involuntary activity at rest
  • Lowered metabolism, heart rate, BP
  • Higher blood flow, salivary, digestive gland secretion
  • Urination, defecation