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Questions and Answers
Which part of the brainstem is responsible for regulating breathing?
Which part of the brainstem is responsible for regulating breathing?
What is the main function of the thalamus in the brain?
What is the main function of the thalamus in the brain?
Which structure connects the right and left cerebral cortices?
Which structure connects the right and left cerebral cortices?
Which lobe of the cerebral cortex is primarily responsible for processing visual information?
Which lobe of the cerebral cortex is primarily responsible for processing visual information?
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Which part of the brain is primarily involved in coordination and learning motor skills?
Which part of the brain is primarily involved in coordination and learning motor skills?
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What does the limbic system primarily handle?
What does the limbic system primarily handle?
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Which structure is NOT part of the diencephalon?
Which structure is NOT part of the diencephalon?
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Which function is controlled by the medulla oblongata?
Which function is controlled by the medulla oblongata?
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Where do action potentials form in myelinated axons?
Where do action potentials form in myelinated axons?
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What is the process called by which action potentials jump between nodes of Ranvier?
What is the process called by which action potentials jump between nodes of Ranvier?
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What type of synapse allows electrical current to flow directly between neurons?
What type of synapse allows electrical current to flow directly between neurons?
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What is the primary function of the central nervous system (CNS)?
What is the primary function of the central nervous system (CNS)?
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What role do neurotransmitters play at chemical synapses?
What role do neurotransmitters play at chemical synapses?
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Which part of the nervous system is primarily responsible for reflex actions?
Which part of the nervous system is primarily responsible for reflex actions?
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What are the two main types of matter found in the vertebrate brain?
What are the two main types of matter found in the vertebrate brain?
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What occurs after a neurotransmitter binds to ligand-gated ion channels in the postsynaptic cell?
What occurs after a neurotransmitter binds to ligand-gated ion channels in the postsynaptic cell?
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What role do afferent neurons play in the peripheral nervous system (PNS)?
What role do afferent neurons play in the peripheral nervous system (PNS)?
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What defines cephalization in bilaterally symmetrical animals?
What defines cephalization in bilaterally symmetrical animals?
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Which structure in invertebrates is similar to the function of the vertebrate brain?
Which structure in invertebrates is similar to the function of the vertebrate brain?
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Which of the following statements is true about synaptic transmission?
Which of the following statements is true about synaptic transmission?
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Where do cranial nerves originate in the nervous system?
Where do cranial nerves originate in the nervous system?
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What structure is involved in the synthesis and packaging of neurotransmitters?
What structure is involved in the synthesis and packaging of neurotransmitters?
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What is the primary function of ganglia in the nervous system?
What is the primary function of ganglia in the nervous system?
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What distinguishes the role of efferent neurons from afferent neurons?
What distinguishes the role of efferent neurons from afferent neurons?
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What are the three main functions of the nervous system?
What are the three main functions of the nervous system?
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What role do glial cells play in the nervous system?
What role do glial cells play in the nervous system?
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Where does the processing of sensory information primarily occur?
Where does the processing of sensory information primarily occur?
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What does the term 'resting potential' refer to?
What does the term 'resting potential' refer to?
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What is the primary function of motor neurons in the nervous system?
What is the primary function of motor neurons in the nervous system?
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What change occurs at the synapses of neurons during signal transmission?
What change occurs at the synapses of neurons during signal transmission?
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What type of cells are responsible for the structural integrity of the nervous system?
What type of cells are responsible for the structural integrity of the nervous system?
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Which structure within a neuron is primarily responsible for receiving information from other neurons?
Which structure within a neuron is primarily responsible for receiving information from other neurons?
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What maintains the concentration gradient of K+ and Na+ across the plasma membrane of a neuron?
What maintains the concentration gradient of K+ and Na+ across the plasma membrane of a neuron?
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Which ions are primarily involved in maintaining the resting potential of a neuron?
Which ions are primarily involved in maintaining the resting potential of a neuron?
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What contributes to the negative charge inside a neuron at resting potential?
What contributes to the negative charge inside a neuron at resting potential?
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What happens during the refractory period after an action potential?
What happens during the refractory period after an action potential?
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How does the presence of a myelin sheath affect the speed of an action potential?
How does the presence of a myelin sheath affect the speed of an action potential?
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Which of the following describes the direction of action potential propagation?
Which of the following describes the direction of action potential propagation?
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What occurs at the site where an action potential is generated in the axon?
What occurs at the site where an action potential is generated in the axon?
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Which glial cells are responsible for forming the myelin sheath in the central nervous system?
Which glial cells are responsible for forming the myelin sheath in the central nervous system?
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What primary function does the motor system of the PNS serve?
What primary function does the motor system of the PNS serve?
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Which of the following describes the autonomic nervous system's role in the PNS?
Which of the following describes the autonomic nervous system's role in the PNS?
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How does the sympathetic division of the autonomic nervous system affect the heart rate?
How does the sympathetic division of the autonomic nervous system affect the heart rate?
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What common physiological action occurs as a result of the parasympathetic division's activation?
What common physiological action occurs as a result of the parasympathetic division's activation?
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Which of the following is NOT a function of the sympathetic division?
Which of the following is NOT a function of the sympathetic division?
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Which division of the autonomic nervous system is primarily responsible for the 'rest and digest' response?
Which division of the autonomic nervous system is primarily responsible for the 'rest and digest' response?
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In which aspect does the enteric division of the autonomic nervous system primarily contribute?
In which aspect does the enteric division of the autonomic nervous system primarily contribute?
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What effect does the parasympathetic division have on the bronchi in lungs?
What effect does the parasympathetic division have on the bronchi in lungs?
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Which neurotransmitter is most commonly associated with the sympathetic division's activation?
Which neurotransmitter is most commonly associated with the sympathetic division's activation?
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Which structure plays a key role in coordinating the nervous system's functions?
Which structure plays a key role in coordinating the nervous system's functions?
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Study Notes
Module BL1004: Animal Physiology
- Module focus is Animal Physiology
- Instructor is Professor Rob McAllen
- Email address is [email protected]
- Office hours by appointment
- Contact details: Email and office hours
Nervous System
- Topic: "Electric signals in animals"
- Source: Chapter 48, page 1125 of Campbell
Integrated Physiological Mechanisms
- Image: Barnacles on a rocky shore
Sponge Diversity
- Image: Multiple sponge varieties displayed
Sponge Film
- Mentions a video or presentation about sponges
Overview: Command and Control Center
- Controls: Feelings, perceptions, and movement
- Enables: Learning, remembering, thinking, and consciousness
- Regulates: Internal body functions and behavior
Overview: Lines of Communication
- Nervous system functions: sensory input, integration, and motor output
- Sensors detect external and internal stimuli, transmitting information
- Sensory information integrated by brain or ganglia
- CNS = Central Nervous System (brain and spinal cord)
- Motor output from brain or ganglia to motor neurons for responses
- Examples include doctor-knee-jerk responses and peripheral nervous systems.
Neurons
- Function: Transmission of signals
- Dendrites: Highly branched extensions receiving signals from other neurons
- Axon: A typically much longer extension transmitting signals from terminal branches to other cells at synapses
- Cell body: Contains most neuron organelles
- Glia: Cells nourishing and insulating neurons, crucial for structural integrity and nervous system function.
Neuron
- Every cell has membrane potential (voltage difference across plasma membrane)
- Messages transmitted via membrane potential changes
- Resting potential: Membrane potential when a neuron is not sending signals
- Ion pumps and channels maintain resting potential
Neuron - Formation of the Resting Potential
- K+ concentration is higher inside the cell, Na+ higher outside
- Sodium-potassium pumps use ATP energy to maintain K+ and Na+ gradients across the plasma membrane
- Concentration gradients represent chemical potential energy
Neuron - Formation of the Resting Potential
- Ion channel opening converts chemical into electrical potential
- K+ diffuses out of the cell, anions trapped inside contribute to neuron's negative charge
Neuron - Formation of the Resting Potential
- In a resting neuron, K+ and Na+ currents are equal and opposite, maintaining a steady resting potential across the membrane
Formation of Action Potentials
- Action potentials are formed by depolarization, creating an electrical current that depolarizes neighboring regions of the axon membrane.
- Inactivation of Na+ channels prevents backward action potential transmission; they travel only in one direction, toward synaptic terminals
- Rest and recovery phase, with inactivation of sodium channels being critical
Conduction of Action Potentials
- Speed increases with axon diameter and myelination
- Myelin sheaths made by glia (oligodendrocytes in CNS, Schwann cells in PNS)
- Saltatory conduction: Action potentials jump between nodes of Ranvier in myelinated axons.
Neurons Communicate at Synapses
- Synapse: Junction between cells controlling communication
- Electrical synapses: Electrical current flows between neurons directly across gap junction.
- Chemical synapses: neurotransmitters carry information across the gap junction, resulting mostly in chemical responses.
There Are Two Types of Synapses
- Synaptic terminals transmit information in the form of chemical messengers (neurotransmitters).
- Information transmitted from presynaptic cell (neuron) to postsynaptic cell (neuron, muscle, gland cell)
Chemical Synapses
- Presynaptic neuron synthesizes and packages neurotransmitters into synaptic vesicles in the synaptic terminal
- Action potential triggers neurotransmitter release
- Neurotransmitter diffuses across synaptic cleft, received by postsynaptic cell
Chemical Synapses
- Direct synaptic transmission: Neurotransmitters bind to ligand-gated ion channels in the postsynaptic cell inducing postsynaptic potential
- After neurotransmitter release, diffusion out of synaptic cleft and uptake by surrounding cells or degradation by enzymes
Neural Regulation in Animals
- Source: Chapter 49, page 1143 of Campbell
Plane or Axis of Symmetry
- Sponges, cnidarians, some echinoderms can have radial symmetry or no symmetry
- Some worms, mollusks, arthropods, and chordates have bilateral.
Nervous Systems Consist of Circuits of Neurons and Supporting Cells
- Simplest animals have nerve nets (interconnected nerve cells, no central pathway or organization)
- Starfish have nerve nets in each arm, connected by radial nerves to a central nerve ring.
Nervous Systems Consist of Circuits of Neurons and Supporting Cells
- Bilaterally symmetrical animals exhibit cephalization (sensory organs in anterior)
- Relatively simple cephalized animals (like flatworms) have a central nervous system (CNS) with a brain and longitudinal nerve cords
Central Nervous System
- CNS includes brain and spinal cord, where integration of information occurs
- Gray matter is composed of neuron cell bodies, dendrites, and unmyelinated axons
- White matter consists of bundles of myelinated axons
Organization of the Vertebrate Nervous System
- Reflex: Body's automatic response to a stimulus (like knee-jerk reflex)
- Sensory neurons detect stimulus, interneurons transmit the signal, and motor neurons produce the response
Peripheral Nervous System
- PNS transmits information to and from CNS and regulates movement and internal environment
- Afferent neurons transmit information to CNS; efferent neurons transmit it away
- Cranial nerves mostly connect to the head and upper body; spinal nerves connect to parts below the head
Peripheral Nervous System
- PNS components: motor system (voluntary movement) and autonomic nervous system (involuntary regulation of internal organs)
- Sympathetic/parasympathetic divisions of the ANS opposingly affect target organs.
The Brain
- Brainstem coordinates and conducts information between brain centers.
- Brainstem components: midbrain, pons, and medulla oblongata.
- Midbrain centers for sensory information, pons regulates breathing, medulla controls functions (breathing, cardiovascular activity, swallowing, vomiting, digestion)
The Brain
- Cerebellum: Coordination and error-checking during motor, perceptual, and cognitive functions. Also involved in learning and remembering motor skills (eg. hand-eye coordination).
The Brain
- Evolving diencephalon regions: epithalamus (pineal gland, cerebrospinal fluid generation), thalamus (sensory information input/motor output center), hypothalamus (homeostasis and basic survival behaviors).
The Brain
- Cerebrum has right and left hemispheres, each with cerebral cortex (gray matter) overlying white matter and basal nuclei.
- The cerebrum's largest part in humans is the cerebral cortex, highly complex in function.
The Brain
- Corpus callosum is a band of axons connecting right and left cerebral cortices, allowing intercommunication. Right hemisphere controls left body and vice-versa.
The Brain
- Each cerebral cortex side has 4 lobes (frontal, temporal, occipital, parietal).
- Each lobe has sensory areas where information is integrated and association areas
The Limbic System
- Limb system handles emotions and participates in emotional memory formation utilizing structures in the brainstem surrounding the brainstem (amygdala, hippocampus, thalamus)
- Amygdala is deeply involved in emotional experiences, and storage of emotional memories
Memory and Learning
- Learning occurs through new neuron connections or changes in existing connections
- Short-term memory facilitated by hippocampus; long-term memory stored in cerebral cortex
Acknowledgements
- Majority of content sourced from Campbell's Biology
- Specific contributor: Dr Ramiro Crego from the School of BEES.
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Description
Test your knowledge on the nervous system in animals as outlined in Module BL1004. This quiz focuses on electric signals, communication, and physiological mechanisms. Dive into the fascinating world of animal physiology and understand how organisms perceive and respond to stimuli.
