Nervous System and Anatomy
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Questions and Answers

What is the function of the nervous system?

  • Integrated control of the body systems
  • Receive and process information
  • Send signals to muscles and glands
  • All of the above (correct)

    • What are the two parts of the nervous system?

    Central Nervous System (CNS) and Peripheral Nervous System (PNS)

    Collections of cell bodies inside the central nervous system are called __________.

    nuclei

    Anatomy refers to the structure of the body, while physiology concerns how body parts function together.

    <p>True</p> Signup and view all the answers

    What are nerve axons in the CNS called?

    <p>tracts</p> Signup and view all the answers

    Which collections are called ganglia in the peripheral nervous system?

    <p>Collections of cell bodies</p> Signup and view all the answers

    What are the two divisions of the peripheral nervous system?

    <p>motor (efferent) and sensory (afferent)</p> Signup and view all the answers

    What activates and prepares the body for activity, stress, and emergency situations?

    <p>sympathetic nervous system</p> Signup and view all the answers

    Axons can regrow when Schwann cells create a new path for them.

    <p>True</p> Signup and view all the answers

    An axon's membrane is polarized with a resting potential of _, which means it is more negatively charged inside the cell membrane.

    <p>-70 mV</p> Signup and view all the answers

    What are the two main systems that make up the nervous system?

    <p>CNS- Central Nervous System and PNS- Peripheral Nervous System</p> Signup and view all the answers

    Neurons can undergo cell division (mitosis) to replace dead neurons.

    <p>False</p> Signup and view all the answers

    What is the main function of dendrites in a neuron?

    <p>Receiving information from other neurons and conducting impulses to the cell body.</p> Signup and view all the answers

    Axons conduct nerve impulses away from the cell body and terminate in axon ________.

    <p>terminals</p> Signup and view all the answers

    Match the neuroglial cell with its function:

    <p>Schwann cells = Wrap around nerve axons and increase speed of nerve impulses Astrocytes = Control chemical environment of neurons and form the blood-brain barrier Microglial cells = Protect the CNS through phagocytosis Oligodendrocytes = Provide insulation for CNS axons and can have multiple connections</p> Signup and view all the answers

    An impulse from a neuron moves in both directions.

    <p>False</p> Signup and view all the answers

    What is meant by neuron signals being electrochemical in nature?

    <p>Neuron signals being electrochemical means they are carried by both electrical and chemical processes.</p> Signup and view all the answers

    What is the chemical portion of neuron signal transmission?

    <p>The chemical portion involves neurotransmitters released into the synapse.</p> Signup and view all the answers

    How is an impulse passed from one nerve cell to another?

    <p>An impulse is passed by neurotransmitters released into the synapse binding with receptors on the post-synaptic neuron.</p> Signup and view all the answers

    What prevents continuous stimulation of a nerve synapse and how is this accomplished?

    <p>Synaptic inhibition prevents continuous stimulation, achieved through enzymes like Acetylcholinesterase that degrade neurotransmitters.</p> Signup and view all the answers

    What neurotransmitter helps regulate emotional responses and muscle tone?

    <p>Dopamine</p> Signup and view all the answers

    What neurotransmitter is found at the neuromuscular junctions?

    <p>Acetylcholine</p> Signup and view all the answers

    Once ACh is released in the NMJ, what happens to cause muscle contraction to occur?

    <p>ACh binds to muscle cells, causing a sodium influx triggering an action potential, leading to muscle contraction.</p> Signup and view all the answers

    What does the DRG contain?

    <p>The DRG contains the cell bodies of sensory neurons.</p> Signup and view all the answers

    Label the components of the cross section of a spinal cord.

    <p>The components are gray matter, white matter, dorsal roots, ventral roots, dorsal horns, ventral horns, and the central canal.</p> Signup and view all the answers

    Why is a spinal reflex faster than a conscious decision to move by the brain?

    <p>Spinal reflexes are faster due to involving fewer neurons and not requiring the signal to travel all the way to the brain and back.</p> Signup and view all the answers

    List the 5 components of a reflex arc.

    <p>The components are: receptor, sensory neuron, integration center, motor neuron, and effector.</p> Signup and view all the answers

    What type of specialized receptor does the stretch reflex utilize to detect over-stretch?

    <p>Muscle spindles</p> Signup and view all the answers

    What is the purpose of the stretch reflex?

    <p>The stretch reflex aims to protect muscles against excessive lengthening that could cause damage.</p> Signup and view all the answers

    Study Notes

    Anatomy and Physiology

    • The nervous system consists of two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS)
    • The CNS is made up of the brain and spinal cord, which are protected by the skull and vertebral column, respectively
    • The PNS is made up of all nerves that are not in the brain or spinal cord, including cranial nerves and spinal nerves
    • The PNS can be divided into two divisions: sensory (afferent) and motor (efferent)

    Nervous Tissue

    • Nervous tissue is responsible for communication between cells of the body by forming a system of electrical impulses
    • Yellow indicates nervous tissue

    Central Nervous System

    • The CNS is made up of the brain and spinal cord
    • The CNS sends and receives impulses from the peripheral nervous system
    • Nuclei are collections of cell bodies inside the CNS
    • Tracts are collections of nerve axons inside the CNS

    Peripheral Nervous System

    • The PNS is made up of all nerves that are not in the brain or spinal cord
    • The PNS can be divided into two divisions: sensory (afferent) and motor (efferent)
    • Sensory neurons receive information from sensory organs throughout the body and send it to the CNS
    • Motor neurons relay signals from the CNS to muscles and glands

    Neurons

    • Neurons are nerve cells that conduct electrical impulses and relay information throughout the body
    • Neurons are made up of three basic parts: dendrite, cell body, and axon
    • Dendrites receive information from other neurons and conduct impulses to the cell body
    • Cell bodies synthesize all nerve cell products and receive information from dendrites
    • Axons conduct nerve impulses away from the cell body and terminate in axon terminals
    • Axon terminals store neurotransmitters inside secretory vesicles

    Neurotransmitters

    • Neurotransmitters are chemical messengers that communicate between neurons across a synapse
    • Neurotransmitters are released from axon terminals and bind to receptors on adjacent neurons

    Neuroglial Cells

    • Neuroglial cells are support cells for neurons
    • Schwann cells are a type of neuroglial cell that provides insulation for axons in the PNS
    • Oligodendrocytes provide insulation for axons in the CNS
    • Astrocytes control the chemical environment of neurons and wrap around blood capillaries
    • Microglial cells protect the CNS and engage in phagocytosis

    Action Potentials

    • Resting potential is the state of a neuron at rest, with a negative charge of around -70mV
    • Action potential is a rapid change in polarity across the membrane, resulting in depolarization and repolarization
    • Sodium and potassium gates are special protein-lined channels with gates in the membrane that allow sodium or potassium to pass through
    • Depolarization occurs when the membrane potential becomes more positive, and repolarization occurs when the potential returns to normal

    Chemical Transmission of an Action Potential

    • Synapse is a minute fluid-filled space between the axon terminal of the presynaptic neuron and dendrite of postsynaptic neuron
    • Neurotransmitters are released from axon terminals and bind to receptors on adjacent neurons
    • Chemical transmission occurs when the vesicles filled with neurotransmitters fuse with the plasma membrane and release the neurotransmitters

    Reflexes

    • Reflexes are instantaneous, automatic, and involuntary motor responses within the nervous system
    • Reflexes start from stimuli occurring inside or outside the body and always involve the CNS
    • Examples of reflexes include subconscious reflexes, such as regulation of blood sugar, and conscious reflexes, such as withdrawing a hand from a hot object
    • Reflex arc is the neural pathway that a nerve impulse travels
    • Spinal cord anatomy includes dorsal roots, ventral roots, dorsal root ganglion, gray matter, and white matter
    • Reflexes provide immediate responses to dangerous stimuli and are faster than conscious responses### Reflexes
    • Patellar reflex, also known as knee-jerk reflex, prevents overstretching of quadriceps femoris
    • Flexor withdrawal reflex allows removal of hand from hot or dangerous objects, protecting skin and underlying tissue

    Anatomy and Physiology of the Nervous System

    • Anatomy: structure of the body
    • Physiology: how body parts function together
    • Nervous system: integrates and controls other body systems
    • 2 parts: central nervous system (CNS) and peripheral nervous system (PNS)

    Central Nervous System

    • Composed of brain and spinal cord
    • Protected by skull and spinal vertebrae
    • Collections of cell bodies: nuclei
    • Collections of nerve axons: tracts

    Peripheral Nervous System

    • Includes cranial and spinal nerves that project from CNS
    • Collections of cell bodies: ganglia
    • Collections of nerve axons: nerves
    • 2 divisions: motor (efferent) and sensory (afferent)
    • Motor division: sends signals to muscles and glands
    • Sensory division: receives impulses from sensory organs

    Divisions of the Peripheral Nervous System

    • Motor division: further divided into somatic and autonomic
    • Somatic nerves: under voluntary control, found in skeletal muscles, skin, and joints
    • Autonomic nerves: not under conscious control, found in glands and smooth muscles of organs
    • Autonomic system: divided into sympathetic and parasympathetic systems
    • Sympathetic system: activates and prepares body for activity, stress, and emergency situations
    • Parasympathetic system: operates during normal situations, permits digestion and conserves energy

    Neurons

    • Composed of: axon, cell body, dendrites, and axon terminals
    • 3 unusual characteristics: do not undergo mitosis, require enormous amounts of energy, and can only survive minutes without oxygen
    • Cell body: receives signal, processes it, and manufactures neurotransmitters
    • Dendrites: receive information from other neurons and send signals to cell body
    • Axon: carries signal from cell body to axon terminals
    • Axon terminals: store signals in secretory vesicles, released during electrochemical transmission in the synapse

    Synapse

    • Liquid-filled space between axon terminal of presynaptic neuron and dendrites of postsynaptic neuron
    • Postsynaptic neuron: receives signals from presynaptic neuron
    • Neurotransmitters: synthesized in cell body, stored in axon terminals, and released into synapse

    Types of Neurons

    • Multipolar neurons: 3 or more extensions from cell body, 1 axon, and many dendrites
    • Bipolar neurons: central cell body with 2 extensions
    • Unipolar neurons: 1 extension off cell body, branches into 2 processes
    • Sensory neurons: unipolar, carry information from peripheral to central nervous system
    • Interneurons: also known as association neurons
    • Motor neurons: send messages from central nervous system to peripheral

    Neuroglial Cells

    • Support cells for neurons
    • 4 types in CNS: ependymal cells, oligodendrocytes, astrocytes, and microglial cells
    • PNS: Schwann cells and satellite cells

    Action Potentials

    • Technical term: nerve impulse
    • Caused by movement of unequally distributed ions on either side of plasma membrane
    • Resting potential: -70mV, maintained by pumping 3 sodium ions out and 2 potassium ions in
    • 4 steps: resting state, depolarization, repolarization, and afterpolarization

    Intensity of Sensation

    • Determined by number of neurons and/or frequency of stimulation

    Electrochemical Nature of Neuron Signals

    • Impulse uses both chemical and electrical measures to transmit signal across synapse### Spinal Cord Structure and Function

    • Sensory neurons synapse on cells in the posterior horn of the spinal cord.

    • Motor neuron cell bodies are in the anterior horn of the spinal cord.

    • Motor neurons (axons) leave the spinal cord via the ventral roots.

    Reflex Arc

    • A reflex arc consists of five components:
      • The receptor at the end of a sensory neuron reacts to a stimulus.
      • The sensory neuron conducts nerve impulses along an afferent pathway towards the CNS.
      • The integration center consists of one or more synapses in the CNS.
      • A motor (efferent) neuron conducts a nerve impulse along an efferent pathway from the integration center to an effector.
      • An effector responds to the efferent impulses by contracting (a muscle) or secreting a product (a gland).

    Stretch Reflex

    • The stretch reflex utilizes muscle spindles to detect over-stretch.
    • The purpose of the stretch reflex is to protect the muscle against increases in length that may tear or damage muscle fibers.

    Spinal Reflexes

    • Spinal reflexes are faster because they require fewer neurons and the signal does not have to travel all the way to the brain and back.
    • The signal is sent to the spinal cord and back, which is a shorter distance to travel.

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    Anatomy & Physiology of Nervous System PDF

    Description

    Learn about the structure and function of the nervous system, including its components and relationship with the body. Discover how it receives and processes information to elicit responses.

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