Nervous System I Flashcards
The CNS consists of the ______ and _________ ______ both in the dorsal body cavity.
Brain
Spinal Cord
What protects the CNS?
Surrounding bone. The skull and the vertebrae
The brain is continuous with the spinal cord through the _______ ________ and are lined with protective layers called ___________.
Foramen magnum
Meninges
What is the PNS is made of?
Nerves and ganglia.
What is a nerve?
Bundles of axons and their sheaths
What is a ganglia?
Collection of nervous cell bodies outside of CNS
memorize
How many pairs of cranial nerves are there? From where do they originate?
12
The brain
How many pairs of spinal nerves are there? From where do they originate?
31
The spinal cord
Why are cranial and spinal nerves paired?
Because we’re bilateral beings.
What is the breakdown of spinal nerves?
8 Cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
Where does the first spinal nerve exit?
Between the skull and the atlas
Where do the next 30 nerves exit?
Through the intervertebral foramina, including the ventral and dorsal foramina of the sacrum.
The PNS is divided into what two subdivisions?
Afferent and Efferent
The afferent neurons are also known as?
Sensory
The efferent neurons is also know as?
Motor
The efferent nervous system is subdivided into?
Somatic and autonomic nervous systems
The autonomic nervous system is subdivided into?
The sympathetic and parasympathetic nervous system
What does the afferent system of the PNS do?
Sends information to CNS
What is the somatic afferent sensory system?
Send info from receptors in skin, muscles, bones and joints to the CNS
What is the visceral afferent sensory system?
Send info from receptors in the viscera in thoracic and abdominal cavities to the CNS
What does the efferent system of the PNS do?
Motor division (think effort/exit) Sends info from the CNS to the target (or effector organ)
What does the somatic efferent system do?
Sends information from the CNS to skeletal muscle
How many neuron(s) are in the somatic efferent pathyway?
One
What does the autonomic efferent system do?
Send information from the CNS to smooth muscle, cardiac muscle, and the glands
How many neuron(s) are in an autonomic efferent pathway?
Two
What is the sympathetic nervous system?
“Fight or flight”
What does the sympathetic nervous system do?
It prepares the body for physical activity
What is the parasympathetic nervous system?
Rest or relaxation
What does the parasympathetic nervous system do?
Regulates resting functions, eg digestive and urinary systems
