Week 1: Introduction to Neuroscience Flashcards
The main functions of the nervous system are:
- control
- regulate
- communicate
The main systems of the nervous system are:
- sensory systems
- memory systems
- associational systems
What are the components of the CNS?
brain and spinal cord
what are the 2 large divisions of the PNS?
Somatic Nervous System and Autonomic nervous system
The autonomic nervous system contains the:
- somatic nervous system
- parasympathetic nervous system
- enteric nervous system
The somatic nervous system contains:
- cranial nerves and branches
- spinal cords and branches
what are the components of a neuron?
- dendrites
- soma
- axon hillock
- axon
- terminal branches
What is the function of dendrites?
What is the function of soma?
Dendrites: receive all information!
Soma: where the info from the dendrites is directly related
What is the function of the axon hillock? What is important about this component?
axon hillock connects the cell body and the axon.
It acts as a gateway to the axon. This is where the signal can die off or if it is important enough, it will go through to the axon.
what is the job of the axon? What are two important structures that we see here?
to pass information along!
nodes of Ranvier and myelin
The job of myelin is to help:
speed up the transference
The job of the nodes of Ranvier is to:
speed up the signal
This type of neuron has several dendrites and axons and it is considered to be the most common.
Multipolar neurons
This type of neuron is sometimes found in the eyes or nose but is overall rare in humans. It classified as a single dendrite and a single axon, has 2 long axons and mostly found in invertebrates.
bipolar neurons
These neurons come off the cell body, has bidirectional information, and is typically classified as going TOWARDS the PNS. It is almost exclusively in the PNS.
Pseudo Unipolar
Sensory neurons are ___________ signals from the receptor to the CNS.
afferent
What are the 3 types of sensory neurons?
- special sensory
- viscerosensory
- somatosensory
Which sensory neurons are a conscious transmission from skin, muscle and joint receptors on the cortex?
somatosensory
What are the 2 types of motor neurons?
efferent signals from CNS to effectors
somatomotor neurons go from CNS to:
autonomic motor neurons go from CNS to:
- Skeletal muscles (voluntary contractions)
- Smooth muscle, cardiac muscle, glands (involuntary contractions)
What are the characteristics of interneurons?
- The are found in the brain and spinal cord
- they are also called associative neurons.
- the connect sensory and motor neurons and mediate their functions
A reflex is:
a unidirectional, rapid, predictable, and involuntary response to a stimulus.
What is the neural pathway that controls a reflex?
sensory receptor → sensory neuron → interneuron → motor neuron → effector
The flexor withdrawal reflex and the myotatic reflexes are types of:
Somatic reflexes
The salivary reflex and pupillary reflexes are types of:
autonomic reflexes
In the myotatic reflex, what is the purpose of the interneuron?
To inhibit motor neurons to the flexor muscles
What is the flexor reflex?
painful stimulus → sensory receptor → sensory neuron → interneurons → motor neurons → excitation of flexors, inhibition of extensors
what is the crosses extension reflex?
painful stimulus → sensory receptor → sensory neuron → interneuron crosses midline → motor neurons → excitation of extensors and inhibition of flexors.
Glial cells are support cells. How many glial cells to every neuron?
10
What are the 4 CNS glia or neuroglia?
- Astrocytes
- oligodendrocytes
- ependymal cells
- microglia
Astrocytes are crucial structures because:
- support cells
- they are insulators
- assist with tissue repair
- impact neurotransmitter activity
- assist with the blood brain barrier
Ependymal cells line the ventricle and central canal of the walls. What structure do they form?
Choroid plexus
What is the importance of CSF as it relates to Ependymal cells?
Ependymal cells help facilitate CSF exchange and these cells also aid in production of CSF.
Microglia are the:
macrophages of CNS
What are the functions of oligodendrocytes?
CNS myelin creation
One cell can myelinate multiple axons
astrocytes are the CNS equivalent of PNS structures called:
satellite cells
The myelin is a:
mixture of proteins and phospholipids that wrap around the axon, forming a white insulating sheath.
The myelin is not continuous. Instead, what structures run between the discontinuities of the myelin sheath?
Nodes of Ranvier
The nodes of ranvier:
enable regeneration of action potentials and facilitates saltatory transmissions.
What is the synapse?
a space for neurons to interact with each other. It can also be a space for neurons to interact with a target organ.
What are the 3 components of a synapse?
- presynaptic nerve terminals
- post synaptic element - dendrite, cell body, target cell
- synaptic cleft
what are the characteristics of an electrical synapse?
- bidirectional
- tight junctions
- gap junctions have large diameter pores for access
- very fast communication but short latency
- less common in nervous system than chemical synapses
What are the characteristics of chemical synapses?
- greater distance between neurons (synaptic cleft)
- slower process
- receptor specific communication
why are there more chemical synapses in the body than electrical synapses?
chemical synapses are more controlled, efficient and specific.
What is occurring at stage 1?
transmitter is synthesize and then stored in vesicles
what is occurring at stage 3?
depolarization of presynaptic terminal causing opening of voltage gated Ca2+ channels
In step 6, that transmitter is being released via:
exocytosis
What is occuring in stage 5 of this picture?
Ca2+ is causing the vesicles to fuse with presynaptic membranes
What ion is more prevalent intracellularly?
K+
Which ions are more prevalent as extracellular components and have crucial roles in maintaining the resting membrane?
Cl - and Na+
Excitatory post synaptic potentials:
- cause depolarization of the cell
- increase the likelihood of Na+ coming into the cell
- increase likelihood of postsynaptic action potential
Inhibitory post synaptic potentials:
- cause hyperpolarization of the cell
- increases likelihood of Cl - going in the cell and hyperpolarizing
- decreases likelihood of postsynaptic action potential
What are temporal summations?
little graded potentials that build up
what is spatial summation?
2 graded potentials that happen at the same time
conduction velocity of the myelin sheath is dependent on:
- fiber diameter
- presence of myelin
- thickness of myelin
- fiber classification
What are the functions of neurotransmitters?
carry messages from neuron to neuron
Glutamate is the primary:
What is it involved in?
excitatory neurotransmitter.
excitatory brain functions, learning, memory and synaptic plasticity
Acetylcholine is vital to:
muscle contractions, autonomic functions, wakefulness, attentiveness, anger, sexuality
GABA is the primary:
It has functions in:
inhibitory neurotransmitter
- inhibiting motor, sensory and cognitive neurons
- sedation
- reducing fear, anxiety and stress
- pain inhibition
Glycine is ionotropic or metabotropic?
only ionotropic.
Where is glycine found?
Brainstem and spinal cord
What is the specific PNS centered neuron?
Epinephine
Which catecholamine is excitatory and inhibitory?
dopamine
serotonin has a correlation to:
- sleep quality
- Gi motility
- mood stabilizer
histamine is secreted:
in the hypothalamus but also found throughout the rest of the body.
Histamine is ionotropic or metabotropic?
metabotropic
