Lektion 7 - Neurons and nervous system Flashcards
What defines the nervous system (very broadly)?
- Electrical signals
- Fast communication
- Short duration
- Through nerve fibers
What are the functions of the nervous system (10 st)?
- Sensing external enviroment
- Sensing the internal enviroment
- Regulation of muscle behaviors
- Regulation of behaviors
- Regulation of hormone secretion
- Integration of several signals
- Maintaining homeostasis
- Thinking/philosophy
- Pain/ avoid danger
What is homeostasis?
State of steady internal physical and chemical conditions maintained by living systems.
What is the fundamental principle of the nervous system?
Integrates signals to elaborate appropriate responses in order to maintain homeostasis
What are the functional units of a nervous system called?
Neurons
What are the components of a neuron?
- Dendrites
- Soma / cell body
- Axon hillock
- Axon
- Terminals (synaptic buttons)
What are the different types of neuron morphologies (different forms)?
1) Unipolar neuron
2) Bipolar neuron
3) Multipolar neuron
4) Pseudo-bipolar neuron
What is the most common neuron morphology in vertebrates?
Multipolar neuron (interneurons and motoneurons)
Pseudo-bipolar neuron (typical sensory neuron)
What is a synapse?
A synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell.
What is an axospinous synapse?
An axo-axonic synapse is a type of synapse, formed by one neuron projecting its axon terminals onto another neuron’s axon.
What are three types of synapses?
1) Synapses with another neuron
2) Neuromuscular junctions
3) Neuroglanduar synapses
What are som advantages of a centralized nervous system?
- Higher density of neurons
- Higher density of synapsis
- Topic organisation
- specialized circuits
MOST IMPORTANT:
- Co-localization with concentrated sense organs
Does all vertebrates have the same brain parts?
Yes, only the size of the different region changes between lineages.
What is CNS?
Central nervous system:
- Motor neurons
- Inter-neurons
What is PNS?
Peripheral nervous system:
- somato-motor axons (cell body in CNS)
- Sensory axons and ganglia
Sympathetic axons and ganglia (motor/effector)
- Parasympathetic axons and ganglia (motor/effector)
What is a short way to differentiate between CNS and PNS?
CNS: The brain and spinal cord
PNS: everything else
In the Na-K pump what is exported and what is imported per cycle?
Th epump exports 3 Na+ and imports 2 K+ per cycle
Is the conc of Na+ high inside the cell or outside of the cell?
The conc of Na+ is low in the cell and high outside of the cell
Is the conc of K+ high inside the cell or low?
The conc of K+ is high in the cell an dlow outside of the cell
What charge is there excess of inside the cell?
Negative charges
What happens if the potassium channels open when there is a K+ gradient across the membrane?
The K+ will rush out of the cell
If the sodium channels opens when there is a Na+ gradient across the membrane what happens?
Na+ will rush into the cell
What are the most important ions in a cell?
K+, Na+ and Cl-
What does it mean for neurons to have a resting potential and what is the resting potential?
Neurons at rest have a high K+ conductivity. The resting potential of neurons is ~-70 mV
