A&P Better Flashcards
The brain and spinal cord are a part of the […]
Central Nervous System
What two types of cells compose the nervous system in humans?
Neurons and Glial cells
What is the term for the cell body of the neuron?
Soma
What are the branched cytoplasmic processes attached to the soma of a neuron which receive signals?
Dendrites
What is the region of the axon attached to the soma called?
Axon Hillock
What is the singular large process of a neuron responsible for transmitting signals?
Axon
What is the region of the axon where neurotransmitters are released or where electrical signals are conducted between cells?
Axon Terminal
What are the swells along the axon capable of neurotransmitter release called?
Varicosity
What are the lipid sheaths surrounding the axon which enable faster conduction called?
Myelin Sheath
What common ion leak channel generates most of the membrane potential?
K+ Leak Channels
What ions are present in higher concentrations outside of the cell?
Cl-, Ca2+, Na+
What ions are present in higher concentrations inside of the cell?
Mg2+, K+
What is the resting membrane potential of Cl- and why?
-70 because it’s an anion that is higher outside of the cell
What channels open past threshold?
Voltage-gated Na+ Channels
What protein establishes the resting concentrations of ions mainly responsible for depolarization and repolarization?
Na+ / K+ Transporter
After the cell reaches a positive membrane potential of 30 mV, repolarization begins. What does this process entail?
The inactivation of Voltage-gated Na+ Channel and the opening of Voltage gated K+ Channels
The absolute refractory period ends when what happens in the cell?
The inactivation gate of Voltage-gated Na+ channels is reopened
What aspect of repolarization affects only the relative refractory period but not the absolute refractory period?
Opening and closure of Voltage-gated K+ channels
Why does an action potential not propagate along the membrane in both directions?
If you have point X on a membrane which is depolarized, it will propagate towards the axon terminal, the side of point X closer to the soma will be in its refractory period. If point X started at the axon hillock, then the soma would have blocked it from occuring.
T/F: Action Potentials always occur at the exact same strength
True
What are the areas lacking myelin sheaths called, what function do they serve?
Nodes of Ranvier; Action Potentials grow weaker as they are conducted, but can fully regenerate strength when they are propagated. Nodes of Ranvier provide a point for them to repropagate.
The jumping of the regeneration of action potential between Nodes of Ranvier is described by what term?
Saltatory Conduction
What motor proteins move organelles towards the axon terminal and what type of transport is this?
Kinesins ; Anterograde Transport
What motor proteins move organelles towards the soma and what type of transport is this?
Dyneins ; Retrograde Transport
What glial cells generate the myelin sheath in the central nervous system?
Oligodendrocytes
What glial cells generate the myelin sheath in the peripheral nervous system?
Schwann cells
What glial cells are responsible for forming the blood brain barrier and providing nutrients for neurons?
Astrocytes
What glial cells form tracts along which neurons develop?
Radial glia
What type of glial cells are the macrophages of the brain?
Microglia
What types of glial cells can act as stem cells?
Radial glia and Astrocytes
What type of glial cells forms cerebrospinal fluid?
Ependymal cells
What type of synapse involves a gap junction instead of a synaptic cleft?
Electrical Synapse
What type of synapses do not allow for variation in strength and are less common?
Electrical Synapse
What type of synapses allow for graded potentials and summation?
Chemical Synapse
What type of synapses involve neurotransmitter release from action potentials?
Chemical Synapse
What type of synapses are more common?
Chemical Synapse
Breakdown the release of neurotransmitters in 5 steps
1) An action potential reaches the axon terminal
2) Voltage-gated calcium channels open and allow extracellular calcium release into the cell
3) Calcium-Calmodulin complexes activate Synaptotagmins
4) Activated Synaptotagmins allow fusion between V-SNAREs and t-SNAREs
5) Exocytosis of vesicles allows the release of neurotransmitters into the synaptic cleft
What type of receptors at chemical synapses results in rapid effects on the postsynaptic cell?
Ionotropic Receptors
What type of receptors at chemical synapses results in a more delayed modular response by the postsynaptic cell?
Metabotropic Receptors
What type of summation describes the process of IPSPs and EPSPs entering from different dendrites affecting postsynaptic potential?
Spatial Summation
What type of summation describes the process of IPSPs and EPSPs entering from the same dendrites in rapid succession affecting postsynaptic potential?
Temporal Summation
What type of rapidly-adapting receptors respond very quickly to their stimulus?
Phasic
What type of slow-adapting receptors respond slowly to the taking-away of their stimulus?
Tonic
What kind of ion-channel receptors has low levels of myelination, can be activated by ligands?
Transient Receptor Potential Proteins
What kind of receptors lack capsular endings, have small diameters, and are unmyelinated?
Nociceptors and Thermoreceptors
What surface-level skin receptors are phasic and detect light touch & vibrations?
Meissner’s Corpuscle
What surface-level skin receptors are tonic and detect steady pressure and texture?
Merkel’s Discs
What deeper skin receptors are phasic and detect deep pressure and high-frequency vibration?
Pacinian Corpuscles
What deeper skin receptors detect skin stretch and are tonic?
Ruffini Endings
What muscle receptors monitor degree and rate of muscle stretch?
Spindle Stretch Receptor
What muscle receptor monitors levels of muscle tension?
Golgi Tendon Organs
What type of neurons travel in descending pathways?
Efferent Neurons
What type of neurons travel in ascending pathways?
Afferent Neurons
What type of neurons carry information between afferent and efferent neurons?
Interneurons
What is the area of response of an afferent neuron called?
Receptive Field
What process results in the amplification of differences in overlapping receptive fields to determine the main location of the stimulus?
Lateral Inhibition
What type of neurotransmitters are derived from amino acids?
Biogenic Amines
What type of neurotransmitters are based on tyrosine?
Catecholamines?
What type of catecholamine derivative forms directly into Dopamine?
L-Dopa
What amino acid breaks down catecholamines and serotonin during reuptake?
Monoamine Oxidase (MAO)
What enzyme converts norepinephrine to epinephrine?
PNMT
What gland is responsible for secreting epinephrine and norepinephrine?
Adrenal Medulla
What two hormones are derived from tryptophan?
Serotonin and Melatonin
What kind of receptors bind serotonin?
5-hydroxytryptamine receptors (5-HT)
What kind of medication works for mood diseases implicated with dysfunction of serotonin?
SSRI
What neurotransmitter is derived from histidine?
Histamines
What glutamate receptors are Na+ channels that have Mg2+ ions that can be removed to allow Ca2+ conductance?
NMDA Receptors
What glutamate receptors exocytose in response to higher intracellular Ca2+ concentrations?
AMDA Receptors
What process of prolonged synaptic strength results from NMDA and AMDA receptors?
Long Term Potentiation
What is the primary inhibitory neurotransmitter which utilizes metabotropic receptors that raise K+ permeability and ionotropic receptors that raise Cl- permeability?
GABA
What amino acid is GABA derived from?
Glycine
What inhibitory neurotransmitter involves Cl- permeability?
Glycine
What neurotoxin causes hyperexcitability by inhibiting glycine?
Strychnine
What is the pathway for Nitric Oxide synthesis?
Arginine –> Citrulline –> Nitric Oxide
What secondary messenger is utilized in Nitric Oxide synthesis?
cGMP
Which cholinergic receptor is ionotropic?
Nicotinic
Which cholinergic receptor is metabotropic?
Muscarinic
What enzyme breaks down acetylcholine in the neuromuscular junction?
Acetylcholinesterase
What poison molecule binds with high affinity to nicotinic receptor but does not activate it?
Curare
What drug molecule binds with high affinity to muscarinic receptors but does not activate it?
Atropine
What bacteria interferes with SNARE complexes in the motor neurons?
Clostridium Botulinum
What bacteria interferes with SNARE complexes in inhibitory neurons?
Clostridium Tetani
What chemical binds to the hydroxyl group of serine in acetylcholinesterase to cause its breakdown?
Sarin
What kind of paralysis results from Tetanus?
Spastic Paralysis
What kind of paralysis results from Botulism?
Flaccid Paralysis
What kind of paralysis results from Sarin gas?
Spastic Paralysis
What receptor is present on the presynaptic neuron?
Nicotinic
What receptor is present on the postsynaptic neuron in the parasympathetic nervous sytem?
Muscarinic
What receptor is present on the postsynaptic neuron in the sympathetic nervous system?
Adrenergic
What gaseous neurotransmitter is released from the hypothalamus in small doses
Carbon Monoxide
What neurotransmitter and neuromodulating peptide induces pain?
Substance P
What 16-31 amino acid peptides are potent endogenous opioids produced in the pituitary gland and hypothalamus?
Endorphins
What 5-amino acid peptides are released in the central nervous system and are local endogenous opioids?
Enkephalins
What neurotransmitter regulates the sleep-wake cycle?
Hypocretins / Orexins
What disease involves randomly falling asleep due to a deficiency in orexins?
Narcolepsy
What purine neurotransmitter is excitatory, involved in nociception, and rapid-acting?
ATP
What purine neurotransmitter is inhibitory, accumulates during wakefulness, and more modulatory (slower-acting)?
Adenosine
What lipid neurotransmitters utilize retrograde neurotransmission?
THC and Endocannabinoids
What are the layers of connective tissue surrounding the brain called?
Meninges
Arrange the three meninges from outermost to innermost
Dura Mater, Arachnoid Mater, Pia Mater
What group of ependymal cells is responsible for cerebrospinal fluid generaiton?
Choroid Plexus
Indicate all of the following that can cross the blood brain barrier and how
A) Blood cells
B) Proteins
C) Glucose
D) Steroids
B) (rare but can be actively transported)
C) (transported across)
D) (diffuse through)
Describe the relative ion concentrations in cerebrospinal fluid
K+ is lower, Na+ is higher
