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What is the primary function of dendrites in a neuron?
What is the primary function of dendrites in a neuron?
What role do Schwann cells play in neuron function?
What role do Schwann cells play in neuron function?
How do chemical synapses predominantly communicate messages?
How do chemical synapses predominantly communicate messages?
What occurs at the axon hillock in a neuron?
What occurs at the axon hillock in a neuron?
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Which of the following statements about synapses is correct?
Which of the following statements about synapses is correct?
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What is the primary function of the relay neuron in the reflex arc?
What is the primary function of the relay neuron in the reflex arc?
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What characterizes a reflex action?
What characterizes a reflex action?
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Which of the following best describes the path taken by nerve impulses during a reflex action?
Which of the following best describes the path taken by nerve impulses during a reflex action?
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How does the brain influence reflex actions, despite not being directly involved?
How does the brain influence reflex actions, despite not being directly involved?
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In higher animals, what is the advantage of sensory neurons synapsing in the spinal cord rather than passing directly into the brain?
In higher animals, what is the advantage of sensory neurons synapsing in the spinal cord rather than passing directly into the brain?
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Which part of the brain is primarily responsible for muscle control and balance?
Which part of the brain is primarily responsible for muscle control and balance?
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What is the function of the hypothalamus?
What is the function of the hypothalamus?
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Which cranial nerve is responsible for the sense of smell?
Which cranial nerve is responsible for the sense of smell?
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In which part of the central nervous system is grey matter predominantly located?
In which part of the central nervous system is grey matter predominantly located?
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What is the primary function of the cerebrum?
What is the primary function of the cerebrum?
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Which cranial nerve plays a crucial role in motor functions for the face?
Which cranial nerve plays a crucial role in motor functions for the face?
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Which structure connects the brain and spinal cord?
Which structure connects the brain and spinal cord?
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Which of the following structures is included in the subcortical structures of the brain?
Which of the following structures is included in the subcortical structures of the brain?
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Which nerve is considered vital for hearing?
Which nerve is considered vital for hearing?
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The cerebrum is composed of which main parts?
The cerebrum is composed of which main parts?
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What is the role of the vagus nerve?
What is the role of the vagus nerve?
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Which structure is NOT a part of the cerebral cortex?
Which structure is NOT a part of the cerebral cortex?
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What role does the basal ganglia play in the brain?
What role does the basal ganglia play in the brain?
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Which of the following is a correct description of the telencephalon?
Which of the following is a correct description of the telencephalon?
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What is the largest part of the human brain?
What is the largest part of the human brain?
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Which subcortical structure is involved in memory formation?
Which subcortical structure is involved in memory formation?
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What property of neurons allows them to respond to stimuli?
What property of neurons allows them to respond to stimuli?
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Which statement describes the 'All or none law' in relation to action potentials?
Which statement describes the 'All or none law' in relation to action potentials?
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In myelinated nerve fibers, what process contributes to the faster velocity of impulse transmission?
In myelinated nerve fibers, what process contributes to the faster velocity of impulse transmission?
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What is the primary role of the myelin sheath surrounding nerve fibers?
What is the primary role of the myelin sheath surrounding nerve fibers?
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What occurs during an action potential in excitable cells?
What occurs during an action potential in excitable cells?
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Which type of stimulus is necessary to trigger an action potential?
Which type of stimulus is necessary to trigger an action potential?
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What effect does myelination have on the conduction of impulses?
What effect does myelination have on the conduction of impulses?
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Which of the following does NOT occur during the action potential of a nerve cell?
Which of the following does NOT occur during the action potential of a nerve cell?
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What is the primary cause of resting membrane potential in neurons?
What is the primary cause of resting membrane potential in neurons?
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During which phase of action potential is it impossible to generate another action potential?
During which phase of action potential is it impossible to generate another action potential?
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What occurs during the depolarization phase of an action potential?
What occurs during the depolarization phase of an action potential?
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What is the role of the Na+/K+ pump in neuron function?
What is the role of the Na+/K+ pump in neuron function?
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What is hyperpolarization in the context of action potentials?
What is hyperpolarization in the context of action potentials?
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What defines a reflex action?
What defines a reflex action?
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What distinguishes the relative refractory period from the absolute refractory period?
What distinguishes the relative refractory period from the absolute refractory period?
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How many neurons are typically involved in most reflex arcs?
How many neurons are typically involved in most reflex arcs?
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Study Notes
Physiology and Pathophysiology (PHO221) - Lecture 3: Nervous System
- Course information:
- Course title: Physiology and Pathophysiology (PHO221)
- Lecturer: Prof. Dr. Noha Nassar
- Department: Pharmacology Department, Faculty of Pharmacy, MSA University
- Semester: Fall 2024
- Lecture number: 3
- Topic: Nervous System
Interactive Methods
-
Teaching methods:
- Explanations with Q&A to enhance student engagement
- Videos and diagrams
- Online quiz on Google Sheet
-
Video links:
- (List of YouTube video links)
References
- Textbook of Medical Physiology
- Guyton and Hall Textbook of Medical Physiology
Nervous System Overview
- The nervous system is comprised of two main parts:
- Central nervous system (CNS): brain and spinal cord
- Peripheral nervous system (PNS): all nerves outside the CNS
- The CNS controls the body's functions by sending and receiving signals through nerves.
Nervous System Subdivisions
- Autonomic nervous system:
- Controls self-regulated, involuntary actions of internal organs, including glands and internal organs.
- Further subdivided into sympathetic and parasympathetic divisions
- Somatic nervous system:
- Controls voluntary movements of skeletal muscles
Subdivisions of peripheral nervous system (PNS):
- Sympathetic division:
- Arousing actions
- Parasympathetic division:
- Calming actions
Divisions of the nervous system diagrammatically:
- Illustrates the relationships among peripheral, central and autonomic and somatic systems
Diagrammatic descriptions:
- Illustrates central parts of the brain and spinal cord
- Illustrates different types of nerves
- Diagram of nerve cells
- Shows functions of the brain in overall diagram
- Indicates location of CNS and PNS components
Human Brain: Major Divisions
- Forebrain:
- Processes sensory information, reasoning and problem solving
- Midbrain:
- Regulates movement and processes visual and auditory information
- Hindbrain:
- Regulates autonomic functions, relays sensory information, coordinates movement, and maintains balance
Human Brain: Subcortical Structures
- Hippocampus: memory, learning and emotion
- Hypothalamus: hormonal production, heart rate, body temperature, hunger, sleep-wake cycle
- Medulla: connection between brain and spinal cord, transmitting signals, controlling autonomic activities (heartbeat, breathing)
- Cerebellum: muscle control, balance, and movement
Human Brain: Lobes
- Frontal lobe: problem-solving, emotions, reasoning, voluntary motor activity, judgment, speaking
- Parietal lobe: right and left perception, sensation, reading, body orientation
- Temporal lobe: understanding language, behavior, memory, hearing
- Occipital lobe: vision, color perception
Human Brain: Brain Stem
- Breathing, body temperature, digestion, alertness, sleep cycles, swallowing
Cranial Nerves
- 12 pairs of nerves connecting brain to body
- Olfactory nerve(smell), Optic nerve (eyes), Oculomotor nerve (eyes), Trochlear nerve (eyes), Trigeminal nerve (face sensory), Abducens nerve (eye), Facial nerve (face), Vestibulocochlear nerve (ear), Glossopharyngeal nerve (tongue, throat), Vagus nerve (organs), Accessory nerve (neck), Hypoglossal nerve (tongue)
Spinal Cord
- Spinal cord structure, segmental organization
- Cervical, thoracic, lumbar, sacral, coccygeal regions
- Different nerves associated with regions of the spinal cord (regions, and functions)
Gray Matter and White Matter
- Gray matter: neuronal cell bodies (40% of the brain)
- White matter: bundles of nerve axons (60% of the brain)
- Describes the location, composition and functions in spinal cord
Neuron Structure and Function
-
The neuron is the basic structural and functional unit of the nervous system.
- Dendrites: receive signals
- Cell body (soma): integrates signals
- Axon: transmits signals
- Myelin sheath: increases signal speed (Schwann cells produce)
-
Types:
- Sensory: (afferent) receive internal and external stimuli, take signals to the CNS
- Motor: (efferent) transmit signals from CNS to effectors (muscles and glands)
- Interneurons: connect sensory and motor neurons
-
Types of neurons (diagrammatic description, types and function):
- Unipolar, Bipolar and Multipolar neuron
Synapses
- Neurons communicate at synapses.
- Most synapses use chemical messengers (neurotransmitters).
- Some synapses are electrical.
Action Potential
- Brief reversal in the membrane potential that is transmitted along the axon
- Occurs in nerve and muscle cells
- Consists of depolarization, repolarization and hyperpolarization phases
Resting Membrane Potential
- Electrical potential difference across the neuron's membrane when it's not sending a signal.
- Maintained by ion pumps and channels.
Causes of Resting Membrane Potential
- Differences in ion concentration across the membrane, especially Na+ and K+
- Active transport by Na+/K+ pump
- Ion channels (passive leak of ions)
- Intracellular proteins with negative charges
Refractory Period
- Time period after an action potential when the neuron cannot readily generate another action potential.
- Two parts (absolute and relative)
Spinal Cord Reflexes
- Involuntary and nearly instantaneous movements in response to a stimulus.
- Reflex arcs involve sensory neurons, interneurons, and motor neurons.
- Reflexes do not always require conscious thought processing
Reflex Arc Components
- Stimulus: initial event
- Receptor: detects stimulus
- Sensory neuron: transmits information to the spinal cord
- Relay neuron: transmits information within the spinal cord
- Motor neuron: transmits information from spinal cord to effector
- Effector: muscle that reacts to response
Neuroglia (Glial Cells)
- Astrocytes
- Ependymal Cells
- Oligodendrocytes
- Microglia
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Description
This interactive quiz is based on Lecture 3 of Physiology and Pathophysiology (PHO221), focusing on the Nervous System. Students will explore the structure and functions of the central and peripheral nervous systems, supplemented by videos and diagrams for enhanced understanding.