Organization of Nervous System, Synapses and Transmitters Flashcards
CNS vs PNS
CNS: Encephalon (brain, brainstem, cerebellum), spinal cord
PNS: Peripheral nervous system (sensory and motor)
What does the autonomic nervous system control?
Autonomic functions (heart rate, respiratory rate, digestion, urination…)
What are the two systems that make up the ANS
Sympathetic nervous system: increases activity of autonomic functions
Parasympathetic nervous system: decreases the activity of autonomic functions
Where do the ANS signals originate from?
The brainstem
Name the 3 major levels of the CNS
Cortical level, subcortical level and the spinal cord level
What does the spinal cord level contain?
Walking circuits
Circuits for reflexes
Circuits for body support (extensors)
Circuits for reflexes that control organ functions
What does the subcortical level contain?
Brainstem (medulla and pons), mesencephalon, hypothalamus, thalamus, cerebellum, and basal ganglia
What does the subcortical level control?
subconscious body activities: arterial pressure, respiration, equilibrium, body temperature, hormonal regulation
What is vagal shock?
loss of consciousness due to lack of blood going to the brain
T/F the stimulation of the sympathetic nervous system is what produces vagal shock
False, the parasympathetic nervous system is responsible for vagal shock
Is the cortical level the superficial layer of the grey or white matter?
Grey matter
What are the functions of the cortical level?
Information processing, memory storage, decision making, thought process
What is the cerebral cortex made up of?
Grey matter
Where is the information in the somatosensory system transmitted to?
spinal cord, reticular substance, cerebellum, thalamus, cerebral cortex
What is the main function of the somatosensory system?
To transmit somatic information from the receptors to the CNS
What does the motor system control?
Skeletal muscle contraction, smooth muscle contraction (internal organs), the activity of exocrine & endocrine glands
In which direction does a signal travel through a neuron?
Cell body (soma) to the dendrites to the axon
Name the four types of neurons
Unipolar neuron
Multipolar neuron
Pseudo-unipolar neuron
Bipolar neuron
Where are unipolar neurons found?
Photoreceptors in the retina
Describe a unipolar neuron
Dendrite & axon are on the same side
Describe the multipolar neuron
Has several dendrites and one axon
Most common cell type (motoneuron, purkinje cell)
Where are pseudo-unipolar neurons found?
They are the sensory neuron in the spinal cord
What do pseudo-unipolar neurons develop from?
From bipolar neurons
Where are bipolar neurons found?
in the eyes, the retina, inner ear & olfactory
Describe the bipolar neuron
One main dendrite and one axon
How is information transmitted within the neuron?
By action potentials
Where do APs start?
Axon hillock
How is information communicated between neurons?
By synapses
Describe the role of Ca2+
Ca2+ enters the cell and causes neurotransmitters to be released form vesicles; amount of neurotransmitters released is directly related o the number of Ca2+ ions that enter
What is a synonym for neurotransmitter?
Ligand
What does the type of neurotransmitter based on?
The action on the postsynaptic neuron
What are the two types of neurotransmitters?
Excitatory: Excite postsynaptic neuron
Inhibitory: Inhibit postsynaptic neuron
Name the excitatory neurotransmitters
Glutamate: Used in every part of the brain and spinal cord
Dopamine: Motor behavior + pleasures + emotional arousal
Norepinephrine: Sleep patterns + focus
Acetylcholine: Activates skeletal muscle
Serotonin: Mood + appetite + sleep + memory + learning
Name the inhibitory neurotransmitters
GABA: used in every part of the brain, balancei n our system, many sedative drugs act by enhancing the effect of GABA
What does GABA stand for
Gamma- amino butyric acid
What are the 4 mechanisms of neurotransmitters release?
- AP arrives at presynaptic terminal
- Local depolarization opens voltage-gated Ca2+ channels and Ca2+ ions flow into terminal
- Ca2+ ions trigger the fusion of synaptic vesicles with the presynaptic membrane
- Release of the transmitter into the synaptic cleft
Name the two types of receptors on the postsynaptic membrane
Ionotropic receptor
Metabotropic receptor
Which receptors are slow/fast acting?
Ionotropic = fats acting (lets ions flow inside
Metabotropic = slow acting (second messenger activator
What are the two types of ion channels in ionotropic receptors?
