Nervous System Flashcards
What are the function of neurons?
To release neurotransmitters into the synapse to communicate with a target cell
What are the function neurosecretory cells?
A nerve cell releasing neurohormones into circulation; hybrid between nervous and endocrine cells
What is the cell body of a neuron?
Soma
What structure receives incoming signals to a neuron?
Dendrites
What is the function of the axon hillock?
Initiates action potentials from soma to axon
What are the 2 types of membrane potentials?
Graded and action potentials
What is a graded potential?
Change of membrane potential due to Na+ ligand-gated channels being ; can occur on dendrites or soma
What is an action potential?
Excessive depolarization that exceeds threshold, can occur from a previous graded potential
What is a myelin sheath?
Fatty, insulation around an axon
What are the myelin sheaths in the PNS called?
Schwann cells
What are the myelin sheaths in the CNS called?
Oligodedrocytes
What are the Nodes of Ranvier?
Spaces between myelin sheaths that are highly concentrated with voltage-gated Na+ channels
What is saltatory conduction?
The skipping of electrical signals on a myelinated axon from node to node
What types of cell-cell communication is there?
Electrical and chemical
Describe electrical communication between cells
Pre- & post-synaptic cells are connected through gap junctions
What are 2 types of receptors that are included in chemical communication?
Ionotropic and metabotropic
What are ionotropic receptors?
Ligand-gated receptors that allow ions to enter after neurotransmitter binding
What are metabotropic receptors?
Receptors that activate other intracellular pathways when bound by a neurotransmitter
Convergent neural networks
Multiple afferent neurons synapse @ 1 efferent neuron
Divergent neural networks
One afferent neuron synapses @ many different efferent neurons
Habituation
Decrease of transmitters overtime due to repeated exposure
Sensitization
Increase response to a gentle stimulus due to its association to a stronger stimulus
Ganglia
Cluster of neuronal cell bodies
What is white matter?
Myelinated axons
Gray matter (Cortex)
Cell body and dendrites
What are 3 protective layers of the CNS? (outside-inside)
Dura mater, Arachnoid mater, Pia mater
3 regions of brain
Hind-, mid- & fore-brain
Left hemisphere of cerebrum
Speech control
Right hemisphere of cerebrum
Perception and orientation
What is a sulcus?
A groove
What is a gyrus?
A fold
4 lobes of the brain cortex
Frontal
Occipital
Parietal
Temporal
What are the different types of systems in a efferent system?
Somatic & autonomic
Somatic system
Voluntary actions (skeletal muscles)
Autonomic system
Involuntary actions (visceral organs)
What neurotransmitter is release at the neuromuscular junction?
Accetylcholine
Where do sympathetic and parasympathetic neurons synapse?
Peripheral autonomic ganglion
What does the medulla oblongata regulate?
Respiration & blood pressure
Criteria to be a neurotransmitter?
1)Synthesized in neurons
2)Released at the presynaptic neuron
3)Bind to receptor on postsynaptic neuron
What are the types of receptors that Ach can bind to?
Nicotinic and muscarinic
What are nicotinic receptors?
Ligand-gated ion channels (ionotropic) found in SNS or PSNS
What are muscarinic receptors?
G-coupled proteins (metabotropic); cascade of many metabolic steps
What types of adrenergic receptors are there?
Alpha and Beta
Agonist
Substance that binds to a receptor and triggers a signalling event
Antagonist
Substance that binds to a receptor, but does not trigger a signalling event
