Histology – Nervous tissue Flashcards
What are the functions of the nervous system?
• Sensation
- Receiving information from the environment
• Integration
- Combination of stimulus with sensations, memories, emotion, etc.
• Creating a response that is either, voluntary or involuntary
Name the division of the nervous system and where they are located
- Central nervous system (CNS), located in the brain and spinal cord.
- Peripheral nervous system (PNS), located beyond the brain and spinal cord.
What are neurons?
Situated in the CNS and PNS, they receive, process and
transmit electrical impulses
Name the characteristics of neurons
Neurons die rapidly when they don’t have oxygen
They do not divide, meaning that they are never gonna get replaced if they die
How do neurons treat information?
• Dendrites receive information from
other neurons.
• Cell body processes the information and decides whether to send message or not along
the axon.
• The axon terminal passes the message to the next cell until it reaches its target.
What does white matter represent?
A region with many axons. It is white because of myelin which is a fatty material.
What does gray matter represent?
Regions with cell bodies and dendrites
What are motor neurons?
Neurons that send electrical impulses from the brain or spinal cord to organs
What is the resting membrane potential?
-70mV
When do ligand-gated channels open?
Following the attachment of a molecule
When do mechanically gated channels open?
Following a distortion of the cell membrane
When do voltage-gated channels open?
Following an electrical change of the membrane (-55mV) once the membrane potential reaches the threshold, an action potential will result.
When do leakage channels open?
They open randomly
What is depolarization?
When the membrane potential becomes less negative (Ex: -70 to -55)
What is hyperpolarization ?
When the membrane potential becomes more negative (Ex: -30 to -70)
