Lecture 8 & 9 Nervous System Flashcards
What are the functions of the nervous system?
- Receiving sensory input
- Process and evaluate information
- Initiate response to information
What are the 2 divisions of the nervous system?
Central Nervous System CNS
- brain and spinal cord
Peripheral Nervous System PNS
- sensory receptors and nerves
What are sensory receptors? Explain.
- Ending of neurons or separate, specialized cells that detect things like temperature, pain, touch, pressure, light, sound, odor
- Found in the skin, joints, and organs
- Sends information to the CNS
What are nerves? Explain.
- A bundle of axons and their sheaths that connect the CNS to sensory receptors, muscles, and glands
- 2 types: cranial & spinal nerves
Where do cranial and spinal nerves originate? How many pairs are there of each?
- Cranial nerves: originate from the brain, 12 pair
- Spinal nerves: originate from the spinal cord, 31 pair
What are ganglions?
Collection of neuron cell bodies outside the CNS
What are plexus?
Extensive network of ventral rami of spinal nerves
What are the divisions of the Peripheral Nervous System? Explain them.
Sensory (Afferent)
- Transmits action potentials from sensory receptors in the body to the CNS
- Enters through the dorsal root
Motor (Efferent)
- Transmit action potentials from the CNS to effectors (muscles, glands)
- Exits through the ventral root
- Has 2 divisions: Somatic & Autonomic
What is the Somatic Nervous System?
Motor Division of the PNS
- Transmits action potentials from the CNS to skeletal muscle
- Voluntary control (we choose to move it or not)
- Single neuron system (one neuron carries the message)
What is the Autonomic Nervous System?
Motor Division of the PNS
- Transmits action from CNS to smooth muscle, cardiac muscle, glands
- Subconscious or involuntary control
- Two neuron system (2 nerves, 2 synapses)
- 3 divisions: Sympathetic, Parasympathetic, Enteric
