The nervous system and neurons Flashcards
What are the two main divisions of the Nervous System?
Central Nervous System (CNS) and Peripheral Nervous System (PNS)
The CNS includes the brain and spinal cord, while the PNS consists of sensory and motor neurons.
What is the function of sensory neurons?
Transmit nerve impulses from receptors to intermediate or motor neurons
Sensory neurons are crucial for conveying information from the environment to the nervous system.
What are Schwann cells?
Cells that surround the axon, providing protection and electrical insulation
Schwann cells also play a role in the removal of cell debris through phagocytosis.
What are Nodes of Ranvier?
Gaps between adjacent Schwann cells where there is no myelin sheath
These nodes facilitate the rapid conduction of nerve impulses along the axon.
What is the resting potential of an axon?
The inside of the axon is negatively charged
This state is maintained by the active transport of sodium (Na+) and potassium (K+) ions.
Fill in the blank: The movement of ions is the actual _______.
impulse
What are the three types of ion channels mentioned?
- Voltage-gated channels
- Ligand-gated channels
- Mechanically-gated channels
Each type of channel opens in response to different stimuli.
True or False: The electrical gradient outside the axon is negative.
False
The electrical gradient outside the axon is positive, while the inside is negative.
What does the term ‘action potential’ refer to?
A rapid change in the membrane potential that occurs when a neuron fires
It is the result of the movement of ions across the neuron’s membrane.
What is the role of intrinsic proteins in the neuron membrane?
They contain channels (ion channels) that regulate ion movement
These channels can have gates that open in response to specific signals.
What is the simplest type of nervous response to a stimulus?
A reflex arc
What are neurones?
Specialised cells adapted to rapidly carrying electrochemical charges called nerve impulses
What are the two major divisions of the nervous system?
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
What does the central nervous system consist of?
The brain and spinal cord
What does the peripheral nervous system consist of?
Pairs of nerves that originate from either the brain or the spinal cord
What are the two types of neurones in the peripheral nervous system?
- Sensory neurones
- Motor neurones
What do sensory neurones do?
Carry nerve impulses from receptors towards the central nervous system
What do motor neurones do?
Carry nerve impulses away from the central nervous system to effectors
What are the two subdivisions of the motor nervous system?
- Voluntary nervous system
- Autonomic nervous system
What is the function of the voluntary nervous system?
Carries nerve impulses to body muscles and is under voluntary (conscious) control
What is the function of the autonomic nervous system?
Carries nerve impulses to glands, smooth muscle, and cardiac muscle and is involuntary (subconscious)
What is the spinal cord?
A column of nervous tissue that runs along the back and lies inside the vertebral column for protection
What does the structure of a mammalian neurone consist of?
- Cell body
- Dendrons
- Axon
- Myelin sheath
