anatomy unit 1 notes: cells & organization
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Anatomy Unit 1 Notes: Cells & OrganizationTRANSCRIPT
ANATOMY
Unit 1 Notes:Cells &
Organization
(1) Neurons• Neuron = Nerve Cell• Types: Multipolar + Unipolar
• Basic Structural Components:– Dendrites (Incoming)– Cell Body (Integrate + Process)– Axon (Outgoing)– Myelin Sheath (Insulation + Speed)– Axon Terminal (Final Destination)
(2) Unipolar Neurons• Use: Afferent Input (Sensory Input)
• Main Job:– Get message to CNS– Let CNS process and decide(NO need to have cell body right by dendrites)
• Process:– Dendrites connected to sensory organ–Message sent to cell body Out Axon–Message sent out of axon terminal
(3) Multipolar Neurons• Use: Efferent Output (Motor Output)
• Main Job:– Organize messages by importance
– Make organs do things
(Important to have cell body right next to dendrites)
• Process:– Cell body directly connected to dendrites
– Dendrites coming from CNS / Efferent path effected organ
(4) Neuroglia• Function: Support, insulate and protect neurons.– Cannot transmit nerve impulses
– Can continuously divide through mitosis
• Types:
– Astrocytes
– Microglia
– Ependymal
– Oligodendrocytes
– Schwann Cells & Satellite Cells
(5) Astrocytes• Connect neurons to capillaries
• Transfer blood-nutrients to neurons (and neuron waste to blood)
(6) Microglia• Phagocytize neuron debris and infectious agents.
(7) Ependymal Cells• Pillow-Shaped cells
• Line brain and spinal cord cavities
• Beat cilia + Circulate cerebrospinal fluid
• Provide Shock Absorption
(8) Oligodendrocytes• Flat, Straw-Shaped cells
• Wrap around a neuron’s axon
• Fatty insulation for axon (myelin sheath)
(9) Schwann & Satellite Cells• Schwann Cell:
– Form Myelin Sheath around axons
–Cover Oligodendrocytes
• Satellite Cell:
–Protective Cushioning
– Surround Cell body of neurons
(10) Junctions• Junction = Meeting of Neuron + Neuron or Neuron
+ Organ– A.K.A. Synapse, Synaptic Cleft
• Nerve Impulse Axon Axon Terminal Release Neurotransmitter– Neurotransmitter = Chemical Message
– Causes an effect
– Binds with cell membrane on other side
(11) Nervous System Organization
CENTRAL NERVOUS SYSTEM
PERIPHERAL NERVOUS SYSTEM(SENSORY / AFFERENT INPUT)
PERIPHERAL NERVOUS SYSTEM(MOTOR / EFFERENT OUTPUT)
BODY(INITIAL STIMULUS
/ IMBALANCE)
AUTONOMIC(INVOLUNTARY)
SOMATIC(VOLUNTARY)
PARASYMPATHETIC(REST & DIGEST)
SYMPATHETIC(FIGHT / FLIGHT)
(12) Defining the Levels• Sensory = Afferent = Going to the CNS
• Motor = Efferent = Going away from the CNS
• Somatic = Voluntary
• Autonomic = Involuntary
• Sympathetic = Emotional
• Parasympathetic = Non-Emotional
(13) Voluntary Responses• Voluntary = You consciously choose to move a
body part / respond.
• Pathway:
Stimulus
Sensory / AfferentDivision
Central Nervous System
Motor / EfferentDivision
Effector Organ
Somatic Division
(14) Involuntary Emotional Responses
• Involuntary = Without control.
• Emotional = Scared, Anxious, Angry, Happy, Excited
• Pathway:
Stimulus
Sensory / AfferentDivision
Central Nervous System
Motor / EfferentDivision
Effector Organ
Autonomic Division
Sympathetic Division
(15) Involuntary Non-Emotional Responses
• Involuntary = Without control.
• Non-Emotional = Every day homeostatic mechanisms.
• Pathway:
Stimulus
Sensory / AfferentDivision
Central Nervous System
Motor / EfferentDivision
Effector Organ
Autonomic Division
Parasympathetic Division