Ninja Nerd Week 1

What are the extensions coming off a neuron called?

Dendrites

What is the circular part of a neuron known as?

The cell body

What is the elongated part of a neuron called?

The axon

What is the part of the axon that comes out of the cell body?

The axon hillock

What is the end of an axon known as?

The axon terminal

What type of channels on dendrites are responsible for generating EPSPs and IPSPs?

Ligand-gated ion channels

What occurs when positive ions enter a neuron?

Depolarization, leading to an EPSP

What happens when negative ions enter a neuron?

Hyperpolarization, leading to an IPSP

What is the role of G protein-coupled receptors on dendrites?

They activate a G-protein, leading to a second messenger and opening another ion channel

What is the rough ER in neurons called?

Nissl Body

What process involves transcribing genes into mRNA in the neuron?

Transcription

What is the function of motor proteins along the axon?

They move vesicles of protein up and down the axon

What do kinesins do in the axon?

Perform anterograde transport, moving materials from the cell body to the axon

What is the function of dyneins in the axon?

Perform retrograde transport, moving materials from the axon to the cell body

What triggers neurotransmitter release at the axon terminal?

Calcium channels opening after sodium channels trigger depolarization

What are V-snares and T-snares involved in?

They are involved in the fusion of neurotransmitter vesicles with the plasma membrane

What are the three types of structural neuron classification?

Multipolar, bipolar, and pseudounipolar neurons

What type of neuron relays sensory information to the CNS?

Sensory neurons

What is the resting membrane potential of neurons typically around?

-70mV to -90mV

What role do sodium/potassium ATPase pumps play in resting membrane potential?

They move 3 Na+ out for every 2 K+ in, making the inside of the cell more negative

What is the Nernst potential?

The equilibrium potential where there is no net movement of ions across the membrane

What is an EPSP?

A graded potential that brings the resting membrane potential closer to threshold

What is an IPSP?

A graded potential that brings the resting membrane potential further from threshold

What is the absolute refractory period?

The time when sodium channels cannot open, preventing another action potential

What are astrocytes and their role in the CNS?

Glial cells that help form the blood-brain barrier and secrete growth factors

What is the primary contribution of astrocytes to the blood-brain barrier?

They secrete small molecules that stimulate endothelial cells

What is the basal lamina?

A layer of connective tissue that underlies the blood-brain barrier.

What role do astrocytes play in the blood-brain barrier (BBB)?

They secrete small molecules that stimulate endothelial cells to form tight junctions, enhancing the selectivity of the BBB.

What is the function of the Area Postrema?

It samples blood for specific chemicals and can activate the chemotrigger zone to stimulate vomiting.

What do the Subfornical Organ (SFO) and Organum Vasculosum Laminae Terminalis (OVLT) do?

They sample blood for osmolarity and trigger actions to regulate blood osmolarity.

How do astrocytes manage potassium levels in the extracellular fluid?

They can uptake excess potassium or pump it back into the extracellular fluid when levels are low.

What is the role of astrocytes in neurotransmitter regulation?

They can take up excess neurotransmitters from the synapse and convert them to a modified form for recycling.

How do astrocytes utilize glucose?

They can break it down to pyruvate for ATP production, store it as glycogen, or convert it to lactate for neuronal use.

What are satellite cells and where are they found?

They are the PNS equivalent of astrocytes, found in dorsal root and autonomic ganglia.

What is the function of oligodendrocytes?

They form the myelin sheath around axons in the CNS and can myelinate multiple axons simultaneously.

What condition is caused by demyelination of CNS axons?

Multiple sclerosis.

What do Schwann cells do?

They myelinate axons in the PNS and can regenerate if damaged.

What is Guillain-Barré syndrome?

A condition caused by demyelination of PNS axons.

What is myelin and its primary function?

A lipid-protein combination that insulates axons to facilitate quicker action potentials.

What is saltatory conduction?

The propagation of action potentials in myelinated axons, where the signal jumps between nodes of Ranvier.

What are the three types of myelinated neurons based on conduction velocity?

Type A (highest), Type B (moderate), and Type C (lowest).

What is the role of ependymal cells?

They are part of the blood-cerebrospinal fluid barrier and help produce and circulate cerebrospinal fluid (CSF).

What is the function of microglia?

They respond to neuronal harm by secreting substances to destroy pathogens, but can also harm neurons.

What are the four lobes of the cerebrum?

Frontal, parietal, temporal, and occipital lobes.

What separates the frontal lobe from the parietal lobe?

The central sulcus.

What is the primary motor cortex and its function?

Located in the precentral gyrus, it is responsible for voluntary movement of skeletal muscles.

What is the motor association cortex?

It is involved in planning, sequencing, and executing movements, consisting of the premotor cortex and supplementary motor area.

What is the function of Broca's area?

It is involved in the production of speech and is located on the non-dominant side of the brain.

What is the corticospinal tract?

A pathway that transmits motor signals from the primary motor cortex to the spinal cord.

What is the corticobulbar tract?

A pathway that innervates cranial nerve nuclei for facial and upper head muscle actions.

What does a motor homunculus represent?

It illustrates the distribution of motor units in the primary motor cortex, with body part size correlating to motor control.

What is the primary function of the Motor Association Cortex (BA #6)?

Involved in fine motor movement, planning, sequencing, and execution of movement.

Which muscles does the Motor Association Cortex innervate?

Trunk muscles (axial muscles) and proximal limb muscles (hips and shoulders).

What areas of the brain does the Motor Association Cortex communicate with?

Basal ganglia and cerebellum.

What cognitive functions does the Prefrontal Cortex (BA #8-14, 25, 32, 45-47) support?

Personality, working memory, cognition, decision-making skills, and motor planning.

How does the Prefrontal Cortex communicate with other brain areas?

It communicates with the hippocampus, hypothalamus, amygdala, ventral tegmental area, and posterior association area.

What is Fronto-temporal Dementia and its effects?

A condition causing aggression, memory loss, poor decision-making, and Parkinson's-like motor deficits due to damage to the prefrontal cortex.

What is the role of the Frontal Eye Fields (FEF) (BA #8)?

Involved in saccadic eye movement and communicates with cranial nerves III and VI.

How does the right Frontal Eye Field control eye movement?

It controls contralateral eye movement by communicating with the left PPRF and CNs.

What is the function of Broca's Area?

Stimulates muscles of speech and communicates with Wernicke's area.

What happens when Broca's Area is damaged?

It leads to nonfluent speech and grammatical errors, known as Broca's Aphasia.

What are the boundaries of the Parietal Lobe?

Located between the central sulcus, lateral sulcus, and parieto-occipital sulcus.

What is the primary function of the Primary Somatosensory Cortex (BA #3, 1, 2)?

Involved in conscious awareness of somatic sensations.

What types of sensations does the Dorsal Column Medial Lemniscus pathway relay?

Fine touch, discriminative touch, proprioception, and vibration sense.

What sensations does the Spinothalamic tract relay?

Pain, temperature, crude touch, and pressure.

What is the role of the Somatosensory Association Cortex?

Analyzes and recognizes somatic sensations and stores memory of these sensations.

What is astereognosis?

The inability to identify objects by touch due to damage to the somatosensory association cortex.

What is the function of the Posterior Association Area?

Integrates multimodal sensory information (visual, auditory, somatic) and communicates with the prefrontal cortex.

What are the boundaries of the Temporal Lobe?

Separated from the parietal and frontal lobes by the lateral sulcus and from the occipital lobe by the pre-occipital notch.

What does the Primary Auditory Cortex do?

Responsible for conscious awareness of sound, including frequency, pitch, and localization.

What is the role of the Auditory Association Cortex?

Analyzes the meaning of sounds based on frequency, pitch, and past memories.

What is Wernicke's Area responsible for?

Comprehension of written and spoken language.

What is the consequence of a lesion in the Primary Auditory Cortex?

Leads to contralateral loss of sound stimulus and difficulty in sound localization.

What is agraphesthesia?

Inability to identify a number traced on the hand, indicating damage to the somatosensory pathways.

What is abarognosis?

Inability to determine basic weight differences, often due to somatosensory cortex damage.

What is the role of Wernicke's Area?

Involved in the comprehension of written and spoken language.

Which areas send stimuli to Wernicke's Area?

Visual area of the occipital lobe and auditory area of the temporal lobe.

What is Wernicke's Aphasia?

A condition caused by damage to Wernicke's area, resulting in fluent but nonsensical speech and lack of comprehension.

How does the Primary Olfactory Cortex process smells?

Odorants activate olfactory receptors, sending signals to the olfactory bulb, which then sends information to the Primary Olfactory Cortex and the association cortex.

What is the function of the association cortex in olfaction?

Analyzes olfactory information and compares it with stored smell memory, linking smells to emotions via the limbic system.

What is the Insular Cortex responsible for?

Processing visceral sensations, taste sensations, and some vestibular sensations.

What separates the parietal and occipital lobes?

The parieto-occipital sulcus.

What are the two main functional areas of the occipital lobe?

Primary visual cortex and visual association cortex.

What happens in the Primary Visual Cortex?

It processes visual stimuli received from the retina and sends it to the visual association cortex.

What is visual agnosia?

A condition where a person can see an object but cannot recognize it due to lesions in the visual association cortex.

What are the primary components of the Basal Ganglia?

Caudate nucleus, putamen, globus pallidus, thalami, subthalamic nuclei, and substantia nigra.

What is the primary function of the Basal Ganglia?

To start, stop, and modulate motor movements.

Describe the direct pathway of the Basal Ganglia.

Stimulates motor activity by sending excitatory signals from the cortex to the striatum and then to the thalamus.

What neurotransmitter is primarily involved in the direct pathway of the Basal Ganglia?

Glutamate.

What is the role of GABA in the Basal Ganglia pathways?

Inhibits action potentials, affecting the flow of signals in the indirect pathway.

What is the function of the indirect pathway of the Basal Ganglia?

Decreases unwanted motor activity by inhibiting signals to the thalamus.

How does the Nigrostriatal Pathway influence motor activity?

Releases dopamine to modulate both the direct and indirect pathways, enhancing desired movements and inhibiting unwanted ones.

What is the difference between D1 and D2 dopamine receptors?

D1 receptors are stimulatory, increasing action potentials, while D2 receptors are inhibitory, decreasing action potentials.

What condition is associated with damage to the direct pathway of the Basal Ganglia?

Parkinson's disease.

What condition is associated with damage to the indirect pathway of the Basal Ganglia?

Huntington's disease.