Nervous System - Divisions and Cells Flashcards
(31 cards)
What are the two major anatomical divisions of the nervous system?
Central Nervous System (CNS) and Peripheral Nervous System (PNS).
What are the main functions of the nervous system?
Maintain homeostasis, cognition and memory, sensory processing, and control of skeletal muscles.
What does the CNS do?
Integrates, processes, and coordinates sensory data and motor commands.
What does the PNS do?
Carries sensory info to the CNS and motor commands from the CNS to the body.
What are the main parts of a neuron?
Soma (cell body), dendrites, axon, axon hillock, and axon terminal.
What is the function of dendrites?
Receive signals from other neurons.
What does the axon do?
Transmits information to other neurons or effectors.
- the axon hillock is the start of the axon
- the axon terminal is the end of the axon and site where the axon passes information to the other neurons or cells.
What is a synapse?
The site of communication between a neuron and another neuron or cell.
- one way travel of communication occurs here.
Why can’t most neurons re-divide?
They lack centrioles and cannot divide.
What are the structural types of neurons?
- Unipolar - dendrites merge into 1 axon, cell body in the middle of the axon
- bipolar - 1 dendrite and 1 axon, cell body between dendrite and axon
- anaxonic - can;t dstniguish dendrites from axons, cell body is central, occur in brain and special sense organs, function is poorly understood.
- multipolar (motor neuron has this structure) - many dendrites, one axon, cell body between dendrites and axon.
What are the functional types of neurons?
Sensory neurons, motor neurons, and interneurons.
What is gray matter?
Areas of the CNS with high concentrations of neuron cell bodies.
What is white matter?
Areas of the CNS with a high density of axons.
What is a tract?
A bundle of axons in the CNS with a common origin and destination.
What is a nerve?
A bundle of axons in the PNS.
What are astrocytes and what is their function?
The largest glial cells; maintain the blood-brain barrier, support neurons, regulate the environment, and form scar tissue, create 3-dimensional framework providing structural support for neurons.
What do ependymal cells do?
Line brain ventricles and spinal cord canal; produce and circulate cerebrospinal fluid (CSF).
What is the function of oligodendrocytes?
Create myelin sheaths (layers of membrane) which wrap the axons of neurons in the CNS.
What are microglia?
Phagocytic glial cells that clean up waste and pathogens in the CNS.
What do satellite cells do?
Regulate the environment around PNS neurons.
What is the role of Schwann cells?
Myelinate axons in the PNS and aid in axon regeneration.
What is the resting membrane potential of a neuron?
-70 mV.
What causes the resting membrane potential?
Unequal distribution of ions across the cell membrane.
What is membrane potential and what forms this?
The electrical difference across the neuron’s membrane due to ion separation.
- negative porteins inside the cell
- ratio of K^+ to Na^+ inside and outside the cell. For every 2 potassium in is 3 sodium out through facilotated diffusion
- and sodium/potassium exchange pump
