Objectives
1. What is the nervous system?
2. What is the function of the nervous system?
3. Define the components of a neural reflex?
4. what are the divisions of the nervous system?
Central Nervous System (CNS)
• Brain
• Spinal Cord
Peripheral Nervous System(PNS)
• Sensory Nervous System
• Motor Nervous System
4. What are the functional parts of the nervous system ?
• Neurons
• Synapses
• Neurotransmitters
• Receptors
What is the Nervous System?
• The master control center of the body
Nervous System Functions
Reflexes
Reflex arcs are reflexes that occur through nervous system and involve both PNS and CNS. They are classified somatic or autonomic reflexes:
1. Somatic Reflexes: involves skeletal muscles such as withdrawal reflexes
2. Autonomic Reflexes: regulate the activity of smooth muscles such as salivary secretion.
Reflexes components:
1. Stimulus
2. Receptor = react to the stimulus 3. Afferent (sensory) neurons
4. CNS (processing center) 5. Efferent (Motor) neurons 6. Effector= muscle
7. Response
Reflexes
Reflexes
Divisions of the Nervous System
The Nervous System
Central Nervous System =CNS
Peripheral
Nervous
System =PNS
Central Nervous System (CNS)
CNS
Brain Spinal
Cord
Peripheral Nervous System (PNS) Anatomical Divisions
PNS
Cranial
nerves Spinal
Nerves
Peripheral Nervous System
Sensory (Afferent)
Somatic Visceral Special
Motor (Efferent)
Somatic Autonomic
Sympathetic Parasympathetic
Peripheral Nervous System (PNS)
Functional Divisions
Peripheral Nervous System (PNS)
Functional Divisions
All together
Functional Components of the Nervous System
1. Neurons 2. Synapses
3. Neurotransmitter
4. Receptors
Neurons
Neurons
• The structural unit (building block) of the nervous system
• Each Neuron has a cell body, dendrites, axon and axon terminal
• Neurons use electrical signals to transmit information
Synapses
• There is always more the one neuron involved in the process of transmitting information
• There is no physical contact between neurons BUT they are in close proximity So they create a synapse
Neurotransmitters
• Neurotransmitters are the chemicals which allow the transmission of signals from one neuron to the next neuron across synapses or to the effector organ
• The action that follows activation of a receptor site may be either excitatory or inhibitory.
Excitatory
Inhibitory
Receptors
References
https://www.youtube.com/watch?v=GIGqp6_PG6k (0-2:10)
https://www.youtube.com/watch?v=q3OITaAZLNc&index=5&list=PLNZqyJns vdMqFNFyHvMFrFnlXLosnwwB_
https://www.youtube.com/watch?v=x8DjPqdlUbg (For images & illustrations)