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Questions and Answers
Which of the following is a key function of the nervous system?
Which of the following is a key function of the nervous system?
MRI is effective at imaging bones.
MRI is effective at imaging bones.
False
What does functional MRI (fMRI) measure?
What does functional MRI (fMRI) measure?
Changes in blood flow
The first modern MRI scanner was developed by _____ in 1980.
The first modern MRI scanner was developed by _____ in 1980.
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What is the role of myelin sheath?
What is the role of myelin sheath?
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Match the following key components of neurons with their functions:
Match the following key components of neurons with their functions:
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Neurons are responsible for supporting, insulating, and protecting the brain.
Neurons are responsible for supporting, insulating, and protecting the brain.
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What is the first stage of how MRI works?
What is the first stage of how MRI works?
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What is the primary function of motor (efferent) neurons?
What is the primary function of motor (efferent) neurons?
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The medulla oblongata is responsible for regulating voluntary muscle movements.
The medulla oblongata is responsible for regulating voluntary muscle movements.
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Name the classes of hormones produced by glands in the endocrine system.
Name the classes of hormones produced by glands in the endocrine system.
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The __________ neuron carries impulses from the CNS to muscles and glands.
The __________ neuron carries impulses from the CNS to muscles and glands.
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Match the following glands with their primary function:
Match the following glands with their primary function:
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Which of the following is NOT a part of the reflex arc?
Which of the following is NOT a part of the reflex arc?
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Neurotransmitters are released to carry signals across synapses and are quickly reabsorbed.
Neurotransmitters are released to carry signals across synapses and are quickly reabsorbed.
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What role does the hypothalamus play in the endocrine system?
What role does the hypothalamus play in the endocrine system?
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The __________ is the part of the brain responsible for coordinating muscle movements and balance.
The __________ is the part of the brain responsible for coordinating muscle movements and balance.
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Which hormone is primarily involved in lowering blood glucose levels?
Which hormone is primarily involved in lowering blood glucose levels?
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What does MRI primarily excel at imaging?
What does MRI primarily excel at imaging?
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MRI was first developed in the 1960s.
MRI was first developed in the 1960s.
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What is the purpose of the myelin sheath in neurons?
What is the purpose of the myelin sheath in neurons?
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The process of __________ is used to align hydrogen atoms in the body during an MRI.
The process of __________ is used to align hydrogen atoms in the body during an MRI.
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Match the following MRI milestones with their corresponding years:
Match the following MRI milestones with their corresponding years:
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Which type of neuron transmits impulses toward the central nervous system?
Which type of neuron transmits impulses toward the central nervous system?
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Functional MRI (fMRI) measures changes in blood flow to assess brain activity.
Functional MRI (fMRI) measures changes in blood flow to assess brain activity.
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List one benefit of using MRI for diagnostic imaging.
List one benefit of using MRI for diagnostic imaging.
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A __________ may be provided to patients during an MRI scan to reduce noise exposure.
A __________ may be provided to patients during an MRI scan to reduce noise exposure.
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What type of response activates muscles or glands in the nervous system?
What type of response activates muscles or glands in the nervous system?
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Which part of the brain is primarily responsible for controlling vital involuntary actions such as heartbeat and breathing?
Which part of the brain is primarily responsible for controlling vital involuntary actions such as heartbeat and breathing?
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The peripheral nervous system (PNS) includes the brain and spinal cord.
The peripheral nervous system (PNS) includes the brain and spinal cord.
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What is the function of neurotransmitters in the nervous system?
What is the function of neurotransmitters in the nervous system?
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In the reflex arc, the __________ neuron is responsible for transmitting signals from the sensory receptor to the interneuron.
In the reflex arc, the __________ neuron is responsible for transmitting signals from the sensory receptor to the interneuron.
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Match the following glands with their main functions:
Match the following glands with their main functions:
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Which phase of nerve impulse involves the exit of K+ ions to restore the resting potential?
Which phase of nerve impulse involves the exit of K+ ions to restore the resting potential?
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All-or-none response means a stimulus must be weak for an impulse to be triggered.
All-or-none response means a stimulus must be weak for an impulse to be triggered.
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What are the two main classes of hormones discussed?
What are the two main classes of hormones discussed?
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The hypothalamus regulates __________ to maintain homeostasis in the body.
The hypothalamus regulates __________ to maintain homeostasis in the body.
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Which neuron type is responsible for processing sensory input and determining responses within the CNS?
Which neuron type is responsible for processing sensory input and determining responses within the CNS?
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Study Notes
Magnetic Resonance Imaging (MRI)
- MRI is an anatomical imaging technique that analyzes neutrons and protons to create detailed soft tissue images. X-rays, CTs, and PET scans are different.
- Bones are not well-visualized by MRI.
- MRI is based on the discovery of nuclear magnetic resonance (NMR) in 1937 by Isidor I. Rabi.
- Key milestones include:
- Raymond Damadian's first MRI prototype in 1974.
- Damadian's first human MRI scan (5 hours) in 1977.
- Paul Bottomley's creation of the first modern scanner in 1980.
- MRI works by aligning hydrogen atoms in the body within a strong magnetic field.
- Only atoms with odd numbers of protons or neutrons are detectable, like Hydrogen-1.
- Radio waves alter hydrogen atom spins, and energy released during their realignment generates detectable signals.
- MRI signals are transmitted to a computer, processed into images based on tissue characteristics using formulas unique to each tissue.
- Patient preparation includes fasting for 6 hours before abdominal MRIs and removing all metal objects.
- During the scan, patients must remain still for 30 minutes to 2 hours, and the machines can be loud, which may necessitate earplugs.
- Functional MRI (fMRI) measures brain activity through changes in blood flow, and color maps show active areas.
- fMRI technology emerged in the 1990s.
- fMRI differentiates between oxygenated and deoxygenated blood to identify active brain regions.
The Nervous System
- The nervous system serves as the body's primary communication and control system, using electrical impulses to manage thoughts, emotions, and actions.
- Key functions include sensory input (detecting changes), integration (processing input), and motor output (activating muscles and glands).
- Supporting cells (glia) provide structural support and protection, while neurons transmit electrical signals.
- Neurons have dendrites to receive signals and axons to send them to other neurons or effectors.
- Myelin sheaths insulate axons, speeding up signal transmission.
- Nodes of Ranvier are gaps in the myelin where signals "jump" for faster conduction.
- Types of neurons include:
- Sensory (afferent) neurons that carry input to the central nervous system (CNS).
- Interneurons that process information in the CNS.
- Motor (efferent) neurons that carry impulses to muscles or glands.
- A reflex arc is the simplest nervous response, involving a receptor, sensory neuron, interneuron (in the spinal cord), motor neuron, and effector.
- The brain may or may not participate.
- Nerve impulses (action potentials) arise from the cell's resting potential (inside negative, outside positive) shifting due to stimulus-induced sodium channel opening.
- Sodium influx initiates depolarization, while potassium outflow causes repolarization.
- Myelinated fibers transmit signals faster.
- Synapses are spaces between neurons, where neurotransmitters (like dopamine) transfer signals.
- Neurotransmitters are broken down or reabsorbed to prevent continuous firing.
- The central nervous system (CNS) comprises the brain and spinal cord.
- The peripheral nervous system (PNS) includes nerves outside the CNS.
- The brain's hindbrain contains the medulla oblongata (controls vital functions), pons (relays signals), and cerebellum (coordinates movement).
- The midbrain relays signals and controls eye and ear reflexes.
- The forebrain includes the cerebrum (largest, controls voluntary functions), thalamus (relay station for sensory signals), and hypothalamus (regulates homeostasis).
- Action potentials follow an "all or none" principle, requiring a stimulus beyond a threshold to initiate.
- Signals travel from axon terminals to dendrites via neurotransmitters at synapses.
Endocrine System
- The endocrine system comprises glands that regulate body processes through hormones.
- Hormones are organic chemicals affecting target cells, travelling via the circulatory system, and controlling aspects like reproduction, growth, and metabolism.
- Actions include altering cell membrane permeability, protein synthesis, enzymatic activity, mitosis, and secretory function.
- Steroid hormones are lipid-soluble, binding intracellularly. Examples include estrogen and testosterone.
- Amino acid hormones are water-soluble, binding to membrane receptors. Examples include insulin and growth hormone.
- Negative feedback loops control hormone levels in the blood.
- Endocrine glands release hormones directly into the bloodstream, unlike exocrine glands, which use ducts to release substances (e.g., sweat, enzymes).
- The hypothalamus controls other endocrine glands and releases hormones, including ADH.
- The pituitary gland is the "master gland," influencing other glands and releasing hormones, such as growth hormone (HGH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), and adrenocorticotropic hormone (ACTH).
- The thyroid gland regulates metabolism via thyroid hormone. Calcitonin lowers blood calcium, and thyroxine influences cellular respiration.
- The parathyroid glands control blood calcium levels.
- The thymus gland supports T-cell development.
- The pancreatic islets have beta cells producing insulin and alpha cells producing glucagon, which together regulate blood glucose.
- The adrenal glands consist of the adrenal cortex (producing corticosteroids) and adrenal medulla (releasing adrenaline and noradrenaline).
- The testes produce testosterone; ovaries produce estrogen and progesterone.
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Description
This quiz covers the fundamentals of Magnetic Resonance Imaging (MRI), including its development, technological milestones, and operational principles. Learn how MRI distinguishes between soft tissues and why certain atom types are detectable. Test your knowledge about patient preparation and the imaging process.
