Nervous System Flashcards
What is a nerve net?
This means that neurons are all over the place and they communicate without a central processing unit.
What is cephalization?
The concentration of neurons and nerves into the formation of a brain.
What are the two divisions of the nervous system, and what does each do?
- Central nervous system (CNS): integration
- Peripheral nervous system (PNS): sensing, motor output, etc.
In vertebrate animals, what structures make up the CNS?
The brain and spinal cord.
In vertebrate animals, what structures make up the PNS?
Nerves and ganglia.
What three types of tissue is the brain divided into?
- Gray matter
- White matter
- Cerebrospinal fluid
What is gray matter composed of?
Neuron cell bodies.
What is white matter composed of?
Bundled axons. Because the axons are myelinated, and myelin is composed primarily of lipids, this gives the white matter its color.
In the brain, where is gray matter found?
On the outside.
In the brain, where is white matter found?
On the inside.
In the brain, where is the cerebrospinal fluid found?
In the ventricles and periphery.
In the spinal cord, where is gray matter found?
On the inside.
In the spinal cord, where is white matter found?
On the outside.
In the spinal cord, where is the cerebrospinal fluid found?
In the central canal and periphery.
What is the function of cerebrospinal fluid?
Protection and homeostasis.
What are the two efferent components of the PNS?
- Motor system
- Autonomic nervous system
What does the motor system do?
It signals skeletal muscles for both voluntary and involuntary movements using neurons that synapse directly with the muscle and releasing acetylcholine as a neurotransmitter.
What does the autonomic nervous system do?
It manages involuntary processes by targeting smooth muscle, cardiac muscle, or glands.
What are the three divisions of the autonomic nervous system?
- Sympathetic division
- Parasympathetic division
- Enteric division
Describe the path of a neuronal signal from the autonomic nervous system.
This pathway uses two neurons. The first exits the brain and will synapse with another neuron at a ganglion (for both parasympathetic and sympathetic) and release acetylcholine. The second neuron that synapses with the cell that will perform the desired activity will release a different neurotransmitter based on if it is sympathetic or parasympathetic.
If a neuron is sympathetic, what neurotransmitter will it release?
Norepinephrine.
If a neuron is parasympathetic, what neurotransmitter will it release?
Acetylcholine.
Where is the enteric division active?
In the digestive tract, pancreas, and gallbladder.
If a neuron is from the enteric division, what neurotransmitter will it release?
Mostly acetylcholine.
What type of responses does the sympathetic division control?
The sympathetic division corresponds to arousal and energy generation, including fight or flight.
Where do sympathetic nerves exit the CNS?
Most nerves exit the CNS midway along the spinal cord (thoracic and lumbar regions) and form synapses just outside the spinal cord.
What type of responses does the parasympathetic division control?
This division promotes calming and a return to self-maintenance.
Where do parasympathetic nerves exit the CNS?
Most nerves exit at the base of the brain (top of the cervical region) and form synapses near or within an internal organ.
Describe the structure of the cerebrum.
It is the largest part of the brain and is divided into left and right hemispheres.
What does the cerebrum control?
It controls skeletal muscle contraction and is the center for learning, emotion, memory, and perception.
What does the cerebellum control?
It coordinates movement and balance and learns motor skills.
