Lecture Material - CNS & Senses Flashcards
What are the components of the Central Nervous System (CNS)?
brain and spinal cord
What does the Peripheral Nervous System (PNS) include?
all neurons outside the central nervous system, including the somatic and autonomic nervous systems.
What is the main function of the somatic nervous system?
voluntary actions via skeletal muscles
What is the role of the autonomic nervous system?
regulates visceral functions such as heart rate and breathing
What is the enteric nervous system?
part of the autonomic system that controls digestion and gut movement.
what does white matter consist of?
myelinated axons in bundles called tracts
What nervous systems are glia found in and what is their job?
Cells in the CNS and PNS that support and protect neurons.
How many neurons are in the spinal cord?
About 1 billion neurons.
What are the main components of the CNS?
Gray and white matter
How many neurons are estimated to be in the brain?
Approximately 86 billion neurons
what does gray matter consist of?
nerve cell bodies, unmyelinated axons, dendrites
How does the brain use energy?
The brain is 2% of body mass but receives 15% of blood and consumes half of the body’s glucose.
How much energy does the CNS use compared to computers?
The CNS runs on ~40 watts, while computers require much more, like 200,000 watts for complex tasks.
What happens during neuronal communication?
Neurons send action potentials spikes
how much energy do action potential spikes consume?
a lot
How many segments does the spinal cord have?
31 segments
What do dorsal roots do?
carry incoming sensory signals
What do ventral roots do?
carry outgoing motor signals
What shape does the gray matter in the spinal cord take?
It has a butterfly shape with dorsal and ventral horns
What is the job of ascending tracts?
carry sensory signals to the brain
What types of nuclei are found in the gray matter?
Sensory nuclei (in the dorsal horn) and motor nuclei (in the ventral horn)
What is the job of descending tracts?
carry motor signals from the brain
What is a spinal reflex?
A quick response to stimuli that occurs without brain involvement
How many major divisions does the brain have and what are they?
brain has 6 major divisions: cerebrum, diencephalon, midbrain, cerebellum, pons, and medulla.
