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Questions and Answers
What is the primary function of the nervous system?
What is the primary function of the nervous system?
Which component of the nervous system is responsible for voluntary movements?
Which component of the nervous system is responsible for voluntary movements?
Which type of neuron is responsible for carrying signals away from the central nervous system?
Which type of neuron is responsible for carrying signals away from the central nervous system?
What role do glial cells play in the nervous system?
What role do glial cells play in the nervous system?
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Which part of the brain is primarily responsible for processing visual information?
Which part of the brain is primarily responsible for processing visual information?
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Which of the following components is NOT part of the central nervous system?
Which of the following components is NOT part of the central nervous system?
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Which type of neuron is responsible for transmitting signals from sensory organs to the brain?
Which type of neuron is responsible for transmitting signals from sensory organs to the brain?
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What role do neurotransmitters play in the nervous system?
What role do neurotransmitters play in the nervous system?
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Which structure in the brain is primarily responsible for regulating balance and coordination?
Which structure in the brain is primarily responsible for regulating balance and coordination?
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What is the main function of the myelin sheath?
What is the main function of the myelin sheath?
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Which part of the neuron is primarily responsible for receiving signals?
Which part of the neuron is primarily responsible for receiving signals?
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What term describes the gap between two neurons?
What term describes the gap between two neurons?
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What is the result of damage to the myelin sheath?
What is the result of damage to the myelin sheath?
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Which type of glial cell is primarily involved in the maintenance of the blood-brain barrier?
Which type of glial cell is primarily involved in the maintenance of the blood-brain barrier?
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What is one of the functions of the autonomic nervous system?
What is one of the functions of the autonomic nervous system?
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Which structure in the nervous system is primarily responsible for transmitting signals from the central nervous system to muscles?
Which structure in the nervous system is primarily responsible for transmitting signals from the central nervous system to muscles?
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What role do synapses play in the nervous system?
What role do synapses play in the nervous system?
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What is the role of the autonomic nervous system?
What is the role of the autonomic nervous system?
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Which of the following is a characteristic of the central nervous system?
Which of the following is a characteristic of the central nervous system?
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What type of glial cell is primarily involved in the production of myelin?
What type of glial cell is primarily involved in the production of myelin?
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How does the action potential travel along an axon?
How does the action potential travel along an axon?
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What is the primary function of the dendrites in a neuron?
What is the primary function of the dendrites in a neuron?
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Which neurotransmitter is primarily involved in muscle contraction?
Which neurotransmitter is primarily involved in muscle contraction?
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What function do sensory neurons serve in the nervous system?
What function do sensory neurons serve in the nervous system?
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Which structure in the brain is primarily responsible for regulating emotions?
Which structure in the brain is primarily responsible for regulating emotions?
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Study Notes
Nervous System Overview
- The nervous system is composed of two cell types: neurons and glial cells.
- Neurons are the primary functional units, conducting impulses.
- Glial cells support neuron function, acting as connective tissue within the CNS.
Central and Peripheral Nervous Systems
- The central nervous system (CNS) comprises the brain and spinal cord.
- The peripheral nervous system (PNS) consists of nerves.
- The brain is housed within the cranial cavity of the skull.
- The spinal cord is situated within the vertebral canal of the vertebral column.
- The PNS is "peripheral" as it extends beyond the brain and spinal cord.
Nervous System Functions
- Sensory functions: Receiving information about the environment surrounding us (sensation).
- Motor functions: Responding to sensory information.
- Integration functions: Coordinating sensation and response.
Types of Neurons
- Sensory (afferent) neurons carry impulses from receptors in the periphery to the CNS (spinal cord and brain).
- Motor (efferent) neurons transmit signals from the CNS to effector organs (muscles and glands).
- Interneurons connect and transmit signals between afferent and efferent neurons; they're the most numerous.
Sensory Function
- Sensation is the process of receiving environmental information (stimuli).
- Sensory information travels towards the CNS through specific afferent (sensory) branches of the PNS, either from the outside world (somatic sensory) or from inside the body (visceral sensory).
Motor Function
- Responses occur in effector organs (muscles or glands).
- Signals originate from the CNS via the motor (efferent) branch of the PNS.
- Signals to skeletal muscles are carried by somatic motor neurons.
- Signals to cardiac or smooth muscles and glands are carried by autonomic motor neurons.
- Voluntary responses are controlled by somatic motor neurons.
- Involuntary responses are regulated by autonomic motor neurons.
Integration
- Integration is the processing of sensory information and generating a motor response within the CNS.
- It involves comparing sensory input with other stimuli and previous experiences.
- Motor neuron activation based on integration results in a response from the effector organ.
Nervous System Cells
- Neurons transmit information using electrical signals (action potentials).
- They're polarized - unidirectional transmission.
- Dendrites receive signals and propagate to the cell body, then along the axon to terminal ends synapsing with target cells.
- Myelin, a glial sheath, speeds up signal transmission.
- Glial cells provide structural and metabolic support.
Neuron Structure
- Dendrites: Multiple branched extensions receiving signals from other neurons.
- Cell body (soma): Contains cytoplasm and organelles, including the nucleus.
- Axon: Transmits impulses away from the cell body.
- Terminal endings: Transmit signals to other neurons or effector organs.
Neurons
- Neurons are generated early in life and do not regenerate easily.
- Myelin damage causes neurological deficits due to reduced signal transmission speeds.
- Myelin sheath insulation enhances the rapid transmission of information through axons.
Neuron Classification
- Unipolar: One process including both axon and dendrite.
- Bipolar: Two processes (axon and dendrite).
- Multipolar: More than two processes (axon and multiple dendrites).
Overview of the Nervous System
- The brain receives, processes sensory information, initiates responses, stores memories, generates thoughts and emotions.
- The spinal cord conducts signals to and from the brain, acting in reflex activities.
- The PNS (peripheral nervous system) consists of motor neurons (CNS to muscles/glands), and sensory neurons (sensory organs/CNS).
- The somatic nervous system governs voluntary movements.
- The autonomic nervous system manages involuntary responses.
- Sympathetic division- "fight or flight"
- Parasympathetic division- "rest or digest"
Myelination
- Myelinating glia create layers of cell membranes that surround axons.
- Myelin insulates axons, increasing signal transmission speed.
- Schwann cells form myelin in the PNS and Oligodendrocytes form myelin in the CNS
Neuronal Transmission
- Neurons communicate via action potentials.
- Action potentials are electrical signals spreading through the cell membrane by changing its charge.
- Transmit impulse by allowing charged ions to flood the cell membrane.
- Dendrites receive stimulus (neurotransmitters) initiating an action potential.
Resting Membrane Potential
- The resting membrane potential of a neuron is a stable negative charge (-70 mV).
- The state results from the differing ion concentrations inside versus outside the neuron.
- Key ions involved include sodium (Na⁺) and potassium (K⁺).
Action Potential
- Action potential overview
- A significant change in membrane potential caused by ion fluxes
- Review of 2-Minute Neuroscience video on Action Potential (youtube link provided).
Synaptic Transmission
- Synaptic transmission occurs at the synapse (junction of two neurons).
- Neurotransmitters are released from the presynaptic ending across the synaptic cleft to bind with receptors on the postsynaptic membrane.
How do Neurons Communicate?
- A synapse is the site of communication between neurons.
- Synapses occur in two ways - Chemical and electrical.
- Chemical transmission occurs via neurotransmitters diffusing across a synaptic space.
Communication Between Neurons
- Chemical transmission is unidirectional (one-way).
- Neurotransmitters remaining in the synaptic cleft will diffuse away, be reabsorbed, or be destroyed.
Neural Receptors and Sites
- Receptor sites determine the nature of neuronal impulses.
- Inhibitory receptors decrease neuronal activity.
- Excitatory receptors increase neuronal activity.
Glial Cells
- Supportive cells vital for neuron protection and metabolic support.
- Oligodendrocytes, Astrocytes, Microglia, Ependymal are glial cells.
Spinal Nerves
- 31 pairs of spinal nerves connect the spinal cord to the body, each containing sensory and motor neurons.
- Named by vertebra where they exit spinal column.
Central Nervous System
- The CNS consists of the brain and spinal cord.
- Main functions: Sensory Input, Information Processing, Output (motor).
Blood Supply to the Brain
- The brain receives oxygen and nutrients from the cerebral arteries and vertebral arteries.
- Brain uses lots of oxygen & nutrients
- Veins drain the used blood: jugular veins
- Clinical issues: Ischemia, and Hemorrhagic stroke
Protective Structures of the CNS - Meninges
- Meninges are three protective layers around the brain and spinal cord.
- Dura mater (outermost).
- Arachnoid mater (middle).
- Pia mater (innermost).
- The meninges protect the CNS, cushion it, and circulate cerebrospinal fluid (CSF).
Cranial Nerves
- 12 paired cranial nerves emerge from the brain to supply sensory and motor functions of the head and neck, important for senses and movements. (Table with list provided).
Reflexes
- Reflexes are simple, automatic, involuntary responses to stimuli.
- Sensory input triggers a specific motor response through the spinal cord.
Sensory and Motor Pathway
- Sensory pathways relay sensory information from the body to the brain.
- Sensory homunculi depict the cortical representation of sensory areas.
- Motor pathways transmit signals from the brain to the body to control voluntary movements.
- Corticospinal tracts connect the motor cortex to the spinal cord.
The Brain (Review)
- Brain hemispheres communicate via corpus callosum.
- Different brain regions control distinct functions, eg., frontal lobe for speech, temporal lobe for auditory.
- Key parts of the brain and their functions are the brainstem, diencephalon, cerebellum, and cerebral cortex.
Knowledge Check
- Questions assessing understanding of brain regions and functions are provided for review.
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Description
This quiz covers the basic structure and functions of the nervous system, including the roles of neurons and glial cells. You will explore the distinction between the central and peripheral nervous systems, as well as the various types of neurons and their functions. Test your understanding of how the nervous system processes information.
