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Questions and Answers
What primarily creates the resting membrane potential in a cell?
What primarily creates the resting membrane potential in a cell?
Which equation would you use to determine the equilibrium potential for an ion across the membrane?
Which equation would you use to determine the equilibrium potential for an ion across the membrane?
Which term refers to the ability of a membrane to store electric charge?
Which term refers to the ability of a membrane to store electric charge?
What is the main factor affecting the flux of ions across the membrane?
What is the main factor affecting the flux of ions across the membrane?
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In the context of ion channels, what does ion selectivity refer to?
In the context of ion channels, what does ion selectivity refer to?
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Which structure is part of the striatum?
Which structure is part of the striatum?
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Which neurotransmitter is primarily associated with the basal ganglia?
Which neurotransmitter is primarily associated with the basal ganglia?
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What is a common symptom of Parkinson's disease?
What is a common symptom of Parkinson's disease?
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Which type of therapy is NOT used for treating Parkinson's disease?
Which type of therapy is NOT used for treating Parkinson's disease?
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Which of the following is responsible for maintaining posture and balance?
Which of the following is responsible for maintaining posture and balance?
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Which structure is implicated in hemiballism when there is a lesion?
Which structure is implicated in hemiballism when there is a lesion?
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What type of signals are used for communication within the body?
What type of signals are used for communication within the body?
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Which component of the nervous system is responsible for controlling voluntary movements?
Which component of the nervous system is responsible for controlling voluntary movements?
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What is a characteristic feature of Huntington's chorea?
What is a characteristic feature of Huntington's chorea?
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Which structure plays a role in the cortico-basal ganglia-thalamo-cortical loop?
Which structure plays a role in the cortico-basal ganglia-thalamo-cortical loop?
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What is the primary function of action potentials in neurons?
What is the primary function of action potentials in neurons?
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Which system regulates involuntary actions such as heart rate and digestion?
Which system regulates involuntary actions such as heart rate and digestion?
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What is a key characteristic of excitable tissue?
What is a key characteristic of excitable tissue?
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In what way do neurons function similarly to electrical wires?
In what way do neurons function similarly to electrical wires?
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What is the main role of synapses in the nervous system?
What is the main role of synapses in the nervous system?
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What describes the difference between the central nervous system and the peripheral nervous system?
What describes the difference between the central nervous system and the peripheral nervous system?
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What is the main characteristic of an action potential?
What is the main characteristic of an action potential?
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What does the length constant describe in the context of electrotonic conduction?
What does the length constant describe in the context of electrotonic conduction?
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What is the primary role of voltage-gated Na+ channels during an action potential?
What is the primary role of voltage-gated Na+ channels during an action potential?
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What does the time constant (τ) indicate in the context of membrane potential?
What does the time constant (τ) indicate in the context of membrane potential?
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What is saltatory conduction primarily associated with?
What is saltatory conduction primarily associated with?
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Which statement is true regarding excitatory neurotransmitters?
Which statement is true regarding excitatory neurotransmitters?
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What type of response does an electrotonic potential represent?
What type of response does an electrotonic potential represent?
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What is an important feature of the action potential that differentiates it from graded responses?
What is an important feature of the action potential that differentiates it from graded responses?
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What type of receptor is an ionotropic receptor associated with?
What type of receptor is an ionotropic receptor associated with?
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Which statement best describes afterpotential?
Which statement best describes afterpotential?
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What is the primary function of the brainstem?
What is the primary function of the brainstem?
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Which pathways are primarily responsible for the control of distal muscles?
Which pathways are primarily responsible for the control of distal muscles?
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What role does the ascending reticular activating system play?
What role does the ascending reticular activating system play?
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Which area is primarily responsible for the preparation and planning of movements?
Which area is primarily responsible for the preparation and planning of movements?
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Which structure consists of cranial nerves and their nuclei?
Which structure consists of cranial nerves and their nuclei?
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Which reflex involves eye movements that stabilize gaze during head movement?
Which reflex involves eye movements that stabilize gaze during head movement?
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The reticular formation is involved in which of the following functions?
The reticular formation is involved in which of the following functions?
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What is the primary function of vestibular nuclei?
What is the primary function of vestibular nuclei?
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Study Notes
Basal Ganglia Components
- Caudate nucleus, putamen, globus pallidus, subthalamic nucleus, substantia nigra
- Striatum (neostriatum) includes caudate nucleus and putamen
Basal Ganglia Circuits
- Cortico-basal ganglia-thalamo-cortical loop
- Direct and indirect pathways
- Dopaminergic cell group
Basal Ganglia Neurotransmitters
- Dopamine, GABA, Glutamate
Motor Control by Basal Ganglia and Cerebellum
- Basal ganglia: selects and performs cognitive, executive, and emotional programs stored in the cerebral cortex
- Cerebellum: posture maintenance, balance control, coordination, fine motor adjustments, and skilled motor learning
Basal Ganglia Lesions
- Dyskinesia (movement disorder)
- Inability to maintain posture
- Hemiballism (subthalamic lesion)
- Huntington's chorea
- Parkinson's disease
Parkinson's Disease
- Caused by loss of dopaminergic neurons in the substantia nigra
- Symptoms:
- Rigidity (lead-pipe rigidity, cogwheel rigidity)
- Hypokinesia
- Resting tremor
- Therapy:
- L-dopa (dopamine precursor)
- Stem cell therapy
- Transplantation
- Deep brain stimulation
Motor System Summary
- Electrical signals and humoral signals control the body
- The nervous system is organized into the central and peripheral nervous systems
- The nervous system is further divided into motor, sensory, and higher brain functions
- Motor system: controls movement
- Sensory system: receives information from the environment
- Higher brain function: complex cognitive processes
How Signals Are Transmitted to the Brain
- Cell membrane potential
- Action potential
- Cable theory
- Nerve impulse
- Synapse
- Central nervous system and peripheral nervous system
- Autonomic nervous system
Neuron vs Wire Conductor
- Neurons transmit electrical signals through electrochemical processes
- This biological process is similar to the flow of electricity through a wire
Cell Membrane Potential
- Electrically charged or polarized
- Distribution of ions: Na+, K+
- Resting membrane potential: the potential difference across the membrane when the cell is at rest
- Graded potential: a small change in membrane potential that is proportional to the strength of the stimulus
- Action potential: a large, rapid change in membrane potential that travels along the axon
Generating Mechanism of Membrane Potential
- Ionic distribution
- Driving force
- Membrane potential
Ion Channel
- Ion selectivity
- Driving force
- States of channel
- Opening of channel
Na+ & K+ Equilibrium Potential
- Nernst potential: the potential difference across the membrane when the ion is in equilibrium
- Nernst equation: calculates the Nernst potential
Membrane Properties
- Resistance: opposes the flow of electrical current
- Conductance: allows the flow of electrical current
- Capacitance: stores electrical charge
- Polarized, depolarization, repolarization, hyperpolarization
- Spike, all-or-none, afterpotential, propagation
Voltage-Gated Na+ Channel and Voltage-Gated K+ Channel
- Voltage-gated channels open and close in response to changes in membrane potential
- Driving force: the electrochemical gradient that drives ions across the membrane
- Inactivation: a process that closes the channel after it has been open for a certain period of time
Recording of Action Potential
- Electrotonic potential: a passive, graded potential that decays with distance
- Action potential: a self-propagating, all-or-none event
- Threshold: the level of depolarization needed to trigger an action potential
Time Constant
- The time it takes for the membrane potential to reach 63.2% of its final value
- Time constant = Rm x Cm (resistance x capacitance)
Length Constant
- The distance over which an electrotonically conducted signal falls to 37% of its initial value
- Length constant = √(Rm x Cm)
Axon Hillock and Action Potential
- Axon hillock: the region of the neuron where the axon begins
- Action potentials are initiated at the axon hillock
Characteristics of Action Potential
- All-or-none: an action potential either occurs or it does not
- Frequency mode: the frequency of action potentials can vary
Transmission of Myelinated and Unmyelinated Fibers
- Myelinated fibers: conduct action potentials faster due to saltatory conduction
- Unmyelinated fibers: conduct action potentials slower because the signal must travel the entire length of the axon
Synapse
- Synaptic transmission: the process of communication between neurons
- Excitatory: increases the likelihood of the postsynaptic neuron firing
- Inhibitory: decreases the likelihood of the postsynaptic neuron firing
- Neurotransmitters: chemical messengers that transmit signals across synapses
Types of Synapse
- Chemical synapse
- Electrical synapse
Neurotransmitters
- Glutamate, GABA, acetylcholine
Glutamate Receptors
- Ionotropic receptor
- Ionophore
Synaptic Potential
- End plate
- Acetylcholine-gated ion channel
- Electrotonic potential
- Not action potential
Synaptic Transmission in Chemical Synapse
- Action potential arrives at the presynaptic terminal
- Neurotransmitter is released from the presynaptic terminal
- Neurotransmitter binds to receptors on the postsynaptic membrane
- Postsynaptic potential is generated
Coactivation of Alpha and Gamma Motoneurons
- Gamma loop: feedback loop that regulates muscle spindle sensitivity
Topographic Organization of the Ventral Horn
- Motor neurons are organized according to the muscles they innervate
Brain Stem
- Medulla, pons, midbrain, diencephalon
- Regulates blood pressure, respiratory center, temperature regulation, sleep, consciousness, and arousal
- Reticular formation
- Vestibular nuclei
- Cranial nerves and their nuclei
- Ascending lemniscal pathways
- Reticular nuclei
- Descending pathways
- Pathway to and from the cerebellum
Reticular Formation
- Somatic motor control: tone, balance, posture
- Cardiovascular control
- Pain modulation
- Ascending reticular activating system: regulator of consciousness, arousal, attention, sleep, awareness
- Habituation
Descending Motor Pathways
- Pyramidal vs extrapyramidal pathway
- Corticospinal tract
- Motor area
- Lateral vs medial motor system
Lateral vs Medial Motor System
- Lateral motor pathways: control of distal muscles (pyramidal tract, rubrospinal tract)
- Medial motor pathways: control of proximal muscles, posture, ability to stand or sit upright, control righting reflexes (vestibulospinal system)
Vestibular System Reflexes
- Vestibular receptors
- Vestibular nuclei (VN): excitatory to antigravity alpha motoneurons
- Vestibulo-ocular reflex (VOR): eye movements that stabilize gaze during head movement
- Optokinetic reflex; follow objects in motion with stationary head
Motor Cortex
- Primary motor cortex
- Supplementary motor area (SMA)
- Premotor area
- Cingulate cortex
- Posterior parietal cortex
Motor Cortex: Details
- Primary motor cortex: Homunculus
- Supplementary motor area: contextural control, programming complex sequences of movement and coordinating bilateral movements
- Premotor area: prepare for exercise, plan, learn new exercises, "mirror neuron"
Cerebellum
- Cerebellum: coordinates movement and maintains balance
- Cerebellar cortex
- Deep cerebellar nuclei
Cerebellum: Functions
- Controls coordination, balance, and fine motor movements
- Learns new motor skills
- Involved in cognition and language
Human Anatomy and Physiology Course Outline
- The course covers the anatomy and physiology of the human body
- The course is divided into two parts:
- Part I: Communication in the Body and Control of the Body
- Part II: The Motor System, The Sensory System, and the Higher Function of the Brain
- The course includes lectures, dissections, and laboratory exercises
How Can We Transmit Signals to the Brain
- The nervous system controls the body through electrical and chemical signals
- The brain receives sensory information from the environment and sends motor commands to the body
Human Intelligence vs Artificial Intelligence
- Human intelligence: based on biological systems, capable of learning and making decisions, susceptible to error and bias
- Artificial intelligence: based on computer algorithms, capable of performing tasks and processing large amounts of data, limited by its programming
Objectives
- Cell membrane potential
- Action potential
- Cable theory
- Nerve impulse
- Synapse
- Central nervous system and peripheral nervous system
- Autonomic nervous system
- Excitable tissue
Key Facts
- The nervous system is a network of specialized cells called neurons that transmit information throughout the body.
- Electrical impulses are conveyed by neurons throughout the nervous system.
- The brain is the control center of the nervous system.
- Nerves transmit information from the brain to the body and vice versa.
- The brain is responsible for a wide range of functions, including thought, emotion, movement, and sensation.
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Description
Explore the key components and circuits of the basal ganglia, including their role in motor control and neurochemistry. This quiz covers important aspects of basal ganglia lesions and their relation to movement disorders such as Parkinson's disease and Huntington's chorea.
