Brain & Nervous System 1 Flashcards
Describe the stoma of a neuron.
- Neuronal cell body.
- Contains nucleus.
- Site of protein synthesis.
Describe the dendrites of a neuron.
- Many per neuron.
- Receive incoming inputs from other neurons.
- Converge on the stoma.
Describe the axon of a neuron.
- Single axon carries impulse (action potential) to next neuron in series.
- Axon terminal branches into many terminal boutons.
- Insulated with fatty coating termed the myelin sheath.
Define synapses.
The connection between neurons that transmit signals from one cell to next.
Describe the neuronal pathway of signals.
Uni-directional going between axon terminal of nerve 1 and dendrite of nerve 2.
Define divergence and convergence.
Divergence is when synapses expand signals throughout system whereas convergence is when signals are specifically channelled down a certain nerve tract/division.
What determines divergent or convergent pathway?
- Postsynaptic > presynaptic neurons = divergent pathway.
* Presynaptic > postsynaptic neurons = convergent pathway.
Describe afferent neurons.
- Incoming neurons
- Carry info from periphery into nervous system
- Convert sensory info into action potentials
- Uses a variety of specialised receptors to do this.
Describe efferent neurons.
- Outgoing neurons
* Carry commands from nervous system to effectors e.g. Glands, muscles.
Describe interneurons/ circuit/ relay neurons.
- Form connections and circuits between neurons
- Often connect afferent neurons to efferent neurons
- Increase the complexity of the nervous system
- Also involved in storing info.
Define spinal/ withdrawal reflex.
- Involves one afferent, one efferent and one interneuron
- Doesn’t require impulses to travel to brain, only spinal cord
- Facilitates rapid response.
Define ganglia.
Paired or grouped neurons (singular = ganglion).
Define action potentials.
Electrical impulses produced and transmitted by nerve cells.
