Week 3: Nervous System Flashcards
What is the function of the nervous system?
To receive sensory input, process and integrate this sensory input, and activate an appropriate motor response.
What are the 2 major divisions of the nervous system?
Central and peripheral.
What components make up the central nervous system?
Brain and spinal cord.
What is the function of the CNS?
- Processes incoming sensory information.
- Source of thoughts, emotions and memories.
- Source of most signals that stimulate muscles to contract and glands to contract.
What components make up the peripheral nervous system?
All nervous tissue outside of the CNS:
* Nerves that attach to the spinal cord - spinal, cranial, peripheral, ganglia, enteric plexuses, sensory receptors.
* Special sense organs: ears, eyes, tongue, olfactory nerves.
What is a nerve?
A bundle of hundreds to thousands of axons plus associated connective tissue and blood vessels, that lies outside the brain and spinal cord.
How many pairs of cranial nerves emerge from the brain?
12 pairs.
How many pairs of spinal nerves emerge from the spinal cord?
31 pairs.
What is a ganglia?
Ganglia are small masses of nervous tissue, consisting primarily of neuron cell bodies, that are located outside of the brain and spinal cord.
What are ganglia closely associated with?
cranial and spinal nerves.
What are enteric plexuses, and what is their function?
Extensive networks of neurons located in the walls of the organs of the gastrointestinal tract.
The neurons of the enteric plexuses help regulate the digestive system.
What are sensory receptors, and what are examples of them?
A structure of the nervous system that monitors changes in the external or internal environment.
Examples are touch receptors in the skin, photoreceptors in the eye, olfactory receptors in the nose.
What are the functional divisions of the PNS?
- Somatic nervous system
- Autonomic nervous system
- Enteric nervous system
What neurons make up the somatic nervous system?
- Motor neurons that conduct impulses to skeletal muscle only.
- Sensory neurons that convey information from somatic receptors in the head, limbs, skin, and special sense receptors.
Is the somatic nervous system voluntary or involuntary?
The actions of the motor neurons of the SNS are voluntary.
What neurons make up the autonomic nervous system?
The ANS consists of:
* sensory neurons that convey information from autonomic sensory receptors located primarily in visceral organs.
* Motor neurons that conduct nerve impulses to smooth muscle, cardiac muscle, and glands.
Are the actions of the autonomic nervous system voluntary or involuntary?
The ANS is involuntary.
What are the 2 branches of the autonomic nervous system?
- Sympathetic division
- Parasympathetic division
What is the function of the sympathetic division of the autonomic nervous system?
The sympathetic division supports ‘fight-or-flight’ responses, such as increasing heart rate and blood pressure, pupil dilation, slows digestion.
What is the function of the parasympathetic division of the autonomic nervous system?
The parasympathetic division of the autonomic nervous system supports ‘rest-and-digest’ responses, such as lowering heart rate, increasing digestion rate, increasing salivation.
What neurons make up the enteric nervous system?
Neurons in enterix plexuses that extend most of the length of the GI tract. They operate independently of the ANS and CNS.
* Sensory neurons monitor chemical changes within the GI tract as well as the stretching of its walls.
* Motor neurons govern contractions of GI tract smooth muscle, secretions of GI tract organs, and activities of GI tract endocrine cells.
Is the enteric nervous system voluntary or involuntary?
Involuntary
What are the 3 basic functions of the nervous system?
- Sensory function
- Integrative function
- Motor function
What is the sensory function of the nervous system?
Sensory receptors detect internal or external stimuli.