Nervous system Flashcards
(23 cards)
What is the main function of the nervous system?
It coordinates actions and sensory information by transmitting signals to and from different parts of the body
What are the two main parts of the nervous system?
Central nervous system
Peripheral nervous system
What does the central nervous system consist of?
CNS - brain and spinal cord
Describe the peripheral nervous system
PNS - consists of mainly nerves that connect the CNS to every other part of the body
What do you call nerves that transmit signals from the brain to the body?
motor or efferent nerves
What do you call nerves that transmit signals from the body to the brain
sensory or afferent nerves
The peripheral nervous system can be divided into what three subsystems?
And what are each of their functions?
PNS
- somatic - conscious actions - voluntary movement (skeletal muscle)
- autonomic - unconscious actions - internal organs (smooth muscle)
- enteric - subdivision of autonomic (gastrointestinal tract)
What two subsystems can the autonomic nervous system be divided into and what are their general roles?
ANS
- sympathetic - fight or flight
- Parasympathetic - rest and digest
When a cell receives a synaptic signal from a neuron what are the three responses that could be triggered in the post-synaptic cell?
- Excitement
- Inhibition
- Modulation
What are the two broad categories of cells in the nervous system and what are their functions?
- Neurons - transmit signals
2. Glial cells - provide structural and metabolic support
What is the most fundamental function of a neuron?
They communicate with other cells via synapses
Describe a neural synapse.
neural synapse - membrane-to-membrane junctions that contain molecular machinery that allows rapid transmission of signals, either electrical or chemical.
What is an axon?
An axon is a protoplasmic protrusion that can extend to distant parts of the body and make thousands of synaptic contacts.
What are nerves?
Nerves are bundles of axons that extend through the body
Where are the majority of neurons found?
Most neurons are found in the brain and ganglia (centralized structures)
What type of glial cells make up myelin and where are they found?
- Oligodendrocytes - CNS
2. Schwann cells - PNS
What is the function of myelin?
Myelin is a fatty substance that wraps around axons and provided electrical insulation which allows them to transmit action potentials more rapidly and efficiently
What layers envelope the brain and spinal cord to protect it?
Meninges
- Dura mater - tough and thick
- Arachnoid mater - web-like cushion
- Pia mater - delicate and contains blood vessels
What are the three locations we find cell bodies?
- Brain
- Spinal Cord
- Peripheral Ganglia
What are the six most important functions of glial cells?
- Support neurons/hold them in place
- Supply nutrients to neurons
- Insulate neurons electrically
- Destroy pathogens
- Remove dead neurons
- Provide cues to direct axons to their targets
What are the two colors of matter that the nervous system can be divided into?
- Gray Matter - Cell bodies of neurons
2. White Matter - Myelinated axons
What is the difference between a nucleus and a ganglion?
Both are clusters of cell bodies, but their locations differ.
- Nucleus - in brain
- Ganglion - in periphery
There are some exceptions (ie. basal ganglia)
What are action potentials?
Action potentials are neural signals that propagate along an axon in the form of electrochemical waves to produce cell to cell signals at synapses.
