Anatomy and Physiology Quiz
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Questions and Answers

What primarily provides protection to the spinal nerves?

  • Rami communicantes
  • White matter tracts
  • Grey matter cells
  • Nerve plexus (correct)

Which statement about dermatomes is true?

  • They indicate sensory areas related to specific spinal nerves. (correct)
  • They respond directly to pain stimuli.
  • They are monitored by multiple spinal nerve pairs.
  • They develop only during the first year of life.

Which type of reflex involves multiple synapses?

  • Polysynaptic reflex (correct)
  • Innate reflex
  • Monosynaptic reflex
  • Spinal reflex

What characterizes white matter in the spinal cord?

<p>Composed of myelinated axons (B)</p> Signup and view all the answers

Which part of the brain is responsible for processing sensory and motor input?

<p>Cerebrum (A)</p> Signup and view all the answers

What is the primary responsibility of the dorsal horn in the spinal cord?

<p>Processing sensory information (D)</p> Signup and view all the answers

What happens during the activation of a reflex arc?

<p>Motor neuron activation follows after the sensory neuron activation (A)</p> Signup and view all the answers

Which part of the spinal cord is associated with visceral motor function?

<p>Lateral horn (D)</p> Signup and view all the answers

Which structure separates the frontal lobe from the parietal lobe?

<p>Central sulcus (C)</p> Signup and view all the answers

What type of reflex is the patellar reflex classified as?

<p>Monosynaptic reflex (D)</p> Signup and view all the answers

What is the primary function of the ciliary body in the eye?

<p>Secrete aqueous humor (B)</p> Signup and view all the answers

Which part of the eye controls the amount of light entering through the pupil?

<p>Iris (D)</p> Signup and view all the answers

What condition results from the eyeball being too long or the lens being too strong?

<p>Myopia (A)</p> Signup and view all the answers

Which structure in the ear is primarily responsible for converting sound waves into nerve impulses?

<p>Cochlea (C)</p> Signup and view all the answers

What is the role of the vestibular apparatus?

<p>Maintain balance and equilibrium (B)</p> Signup and view all the answers

During which response does the sympathetic nervous system dilate the iris?

<p>Fight or flight (C)</p> Signup and view all the answers

In the visual pathway, where does information from the optic nerves predominantly go?

<p>Visual cortex of the occipital lobe (C)</p> Signup and view all the answers

What is conductive hearing loss primarily caused by?

<p>Issues in the outer or middle ear (A)</p> Signup and view all the answers

What do the otolith organs in the vestibular apparatus detect?

<p>Linear movement and head position (C)</p> Signup and view all the answers

What happens to the lens during the process of accommodation?

<p>It becomes thicker to focus on near objects (D)</p> Signup and view all the answers

What is the role of first order neurons in sensory pathways?

<p>They deliver sensations directly to the CNS. (B)</p> Signup and view all the answers

Which sensory pathway is responsible for conscious sensations of pain and temperature?

<p>Spinothalamic pathway (C)</p> Signup and view all the answers

How do second order neurons differ from first order neurons?

<p>They are located in the spinal cord or brain stem as interneurons. (C)</p> Signup and view all the answers

What type of information does the spinocerebellar pathway deliver?

<p>Proprioceptive information from muscles and joints. (C)</p> Signup and view all the answers

Which statement accurately describes the role of the autonomic nervous system (ANS)?

<p>It regulates major bodily functions outside of conscious awareness. (A)</p> Signup and view all the answers

What is the primary function of the basial nuclei?

<p>To adjust or establish patterns of movement. (B)</p> Signup and view all the answers

In which pathway do messages decussate before ascending to the thalamus?

<p>Spinothalamic pathway (B)</p> Signup and view all the answers

What type of activities primarily engage the medial pathway of the motor command system?

<p>Muscle tone and gross movements of proximal muscles. (A)</p> Signup and view all the answers

Which characteristic is true about visceral sensory pathways?

<p>They provide information to specific centers like the respiratory center. (D)</p> Signup and view all the answers

What differentiates the lateral pathway from the medial pathway in motor control?

<p>The lateral pathway specifically addresses muscle tone in distal limb muscles. (A)</p> Signup and view all the answers

What is the primary function of the Reticular Activating System (RAS)?

<p>Enhance cortical awareness and consciousness (C)</p> Signup and view all the answers

What neurological area is responsible for language comprehension?

<p>Wernicke's area (B)</p> Signup and view all the answers

Which of the following changes in aging can affect motor control?

<p>Slowed reaction times (D)</p> Signup and view all the answers

What is the role of olfactory sensory neurons?

<p>Sense odorants in the environment (D)</p> Signup and view all the answers

What is a key characteristic of gustatory receptors?

<p>Require direct contact with food particles (B)</p> Signup and view all the answers

Which structure of the eye is responsible for focusing light?

<p>Cornea (A)</p> Signup and view all the answers

Which of the following accurately describes olfactory epithelium?

<p>Composed of olfactory sensory neurons, supporting cells, and regenerative basal cells (A)</p> Signup and view all the answers

What happens to the perception of taste as a person ages?

<p>Decrease in the number of taste buds and sensitivity of receptors (A)</p> Signup and view all the answers

Which part of the eye contains light-detecting cells?

<p>Retina (B)</p> Signup and view all the answers

What role do the glomeruli in the olfactory bulb play?

<p>Sort afferent signals based on scent components (A)</p> Signup and view all the answers

How does aging affect the brain's synaptic organization?

<p>Changes in synaptic organization can lead to functional changes (A)</p> Signup and view all the answers

Which type of papillae is NOT involved in tasting?

<p>Filiform papillae (C)</p> Signup and view all the answers

What is the primary role of the ciliary body in the eye?

<p>Produce aqueous humor (B)</p> Signup and view all the answers

What is the primary function of neurons in the nervous system?

<p>Transfer and process information (D)</p> Signup and view all the answers

Which type of neuroglia is responsible for forming the blood-brain barrier?

<p>Astrocytes (C)</p> Signup and view all the answers

What characterizes action potentials in neurons?

<p>They propagate in a nondecremental fashion (B)</p> Signup and view all the answers

What is the role of Schwann cells in the peripheral nervous system?

<p>Myelinate peripheral axons (B)</p> Signup and view all the answers

Which type of postsynaptic potential promotes the generation of an action potential?

<p>Excitatory postsynaptic potential (EPSP) (D)</p> Signup and view all the answers

What occurs during the depolarization phase of an action potential?

<p>Sodium ions influx rapidly (D)</p> Signup and view all the answers

Which type of synapse is characterized by a gap junction allowing direct electrical communication?

<p>Electrical synapse (C)</p> Signup and view all the answers

The outer layer of myelin sheath produced by Schwann cells is known as what?

<p>Neurilemma (D)</p> Signup and view all the answers

Which neurotransmitter is primarily involved in mood regulation and emotional states?

<p>Serotonin (B)</p> Signup and view all the answers

What type of information do proprioceptors provide?

<p>Position and movement of skeletal muscles and joints (C)</p> Signup and view all the answers

At rest, what is the membrane potential of a neuron?

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

Which of the following neurotransmitters is classified as an inhibitory neurotransmitter?

<p>GABA (C)</p> Signup and view all the answers

What is a ramus in the context of spinal nerves?

<p>A branching of spinal nerves to carry information (A)</p> Signup and view all the answers

What is the primary function of the corpus callosum?

<p>Connects the two hemispheres of the brain (C)</p> Signup and view all the answers

Which specialized area is primarily involved in language comprehension?

<p>Wernicke's area (C)</p> Signup and view all the answers

What type of fibers connect the cerebrum to the spinal cord?

<p>Projection fibers (C)</p> Signup and view all the answers

What is the function of the thalamus in the brain?

<p>Acts as a relay point for sensory information (C)</p> Signup and view all the answers

Which structure is known for adjusting postural muscles and coordinating motor patterns?

<p>Cerebellum (B)</p> Signup and view all the answers

What does ataxia refer to in terms of motor control?

<p>Lack of order and coordinated movements (C)</p> Signup and view all the answers

What layer of the cranial meninges is closest to the brain surface?

<p>Pia mater (C)</p> Signup and view all the answers

Which of these functions is NOT associated with the hypothalamus?

<p>Relay of sensory information (A)</p> Signup and view all the answers

Which part of the brainstem is responsible for processing visual and auditory data?

<p>Midbrain (B)</p> Signup and view all the answers

What is the primary role of cerebrospinal fluid (CSF)?

<p>Support and cushioning of the brain (D)</p> Signup and view all the answers

Which layer of the cranial meninges contains dural sinuses?

<p>Dura mater (A)</p> Signup and view all the answers

What kind of neurons are densely packed in the Purkinje cell layer of the cerebellum?

<p>Purkinje neurons (A)</p> Signup and view all the answers

What do astrocytes contribute to in the blood-brain barrier?

<p>Support and maintenance of endothelial cells (C)</p> Signup and view all the answers

Which cranial nerve is responsible for the sense of smell?

<p>Olfactory nerve (CN I) (D)</p> Signup and view all the answers

What type of information do afferent pathways carry?

<p>Sensory information from sensory receptors to the CNS (B)</p> Signup and view all the answers

Which type of receptor provides information about the external environment?

<p>Exteroceptors (D)</p> Signup and view all the answers

What characterizes tonic receptors?

<p>They remain active until the stimulus is removed. (B)</p> Signup and view all the answers

Which type of sensory receptor is specifically responsible for detecting pain?

<p>Nociceptors (C)</p> Signup and view all the answers

What is the main difference between fast pain and slow pain?

<p>Fast pain is transmitted via myelinated fibers while slow pain uses unmyelinated fibers. (A)</p> Signup and view all the answers

Which type of mechanoreceptor is sensitive to high-frequency vibrations?

<p>Lamellar (Pacinian) corpuscles (C)</p> Signup and view all the answers

What process occurs during transduction?

<p>Stimuli are converted into action potentials. (B)</p> Signup and view all the answers

How do proprioceptors contribute to body awareness?

<p>By monitoring muscle tension and joint positions. (B)</p> Signup and view all the answers

Which statement best describes interoceptors?

<p>They monitor changes inside the body, typically not reaching conscious awareness. (D)</p> Signup and view all the answers

What enables the CNS to localize stimuli effectively?

<p>Having smaller receptive fields. (C)</p> Signup and view all the answers

Which neurotransmitters are involved in pain perception?

<p>Substance P and glutamate (C)</p> Signup and view all the answers

What role do baroreceptors play in the body?

<p>Detect pressure changes in blood vessels. (A)</p> Signup and view all the answers

Which characteristic is associated with phasic receptors?

<p>They become less responsive over time. (C)</p> Signup and view all the answers

What defines the receptive field of a sensory receptor?

<p>The area it monitors for stimuli. (C)</p> Signup and view all the answers

What distinguishes chemoreceptors' role in sensory processing?

<p>They do not require conscious awareness for function. (D)</p> Signup and view all the answers

What is the primary function of preganglionic neurons in the autonomic nervous system?

<p>To connect the central nervous system to autonomic ganglia (B)</p> Signup and view all the answers

Which neurotransmitter is primarily released from postganglionic neurons in the parasympathetic nervous system?

<p>Acetylcholine (A)</p> Signup and view all the answers

What effect does activation of the sympathetic nervous system typically have on digestive functions?

<p>Decreased digestive secretions (B)</p> Signup and view all the answers

What characterizes dual innervation in the autonomic nervous system?

<p>Most organs receive input from both the sympathetic and parasympathetic divisions (C)</p> Signup and view all the answers

The adrenal medulla is involved in the release of which substances into the bloodstream?

<p>Epinephrine and norepinephrine (C)</p> Signup and view all the answers

Which cranial nerves are associated with the parasympathetic nervous system?

<p>III, VII, IX, X (B)</p> Signup and view all the answers

Which receptor type is found in the effectors innervated by parasympathetic postganglionic neurons?

<p>Muscarinic receptors (D)</p> Signup and view all the answers

Which type of reflex involves two sets of motor neurons in the autonomic reflex arc?

<p>Long reflexes (B)</p> Signup and view all the answers

What is primarily affected by the activation of the sympathetic nervous system?

<p>Enhanced energy reserves and metabolism (C)</p> Signup and view all the answers

Which classification of reflexes can be described as polysynaptic in nature?

<p>Visceral reflexes (B)</p> Signup and view all the answers

Which ganglion is associated with innervating the organs of the abdominal cavity?

<p>Celiac ganglion (A)</p> Signup and view all the answers

What role does norepinephrine play in the body regarding adrenergic receptors?

<p>Has a longer lasting effect compared to acetylcholine (C)</p> Signup and view all the answers

What is a common physiological effect of the parasympathetic nervous system activation?

<p>Increased digestive secretions (A)</p> Signup and view all the answers

Which part of the nervous system contains adrenergic neurons?

<p>Sympathetic nervous system (A)</p> Signup and view all the answers

Flashcards

Central Nervous System (CNS)

The part of the nervous system that includes the brain and spinal cord, responsible for processing and coordinating information.

Peripheral Nervous System (PNS)

The part of the nervous system that connects the CNS to the rest of the body, carrying information to and from the CNS.

Afferent Fibers

Nerves that carry sensory information from the PNS to the CNS.

Efferent Fibers

Nerves that carry motor commands from the CNS to the PNS.

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Somatic Nervous System (SNS)

The part of the PNS that controls voluntary movements of skeletal muscles.

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Autonomic Nervous System (ANS)

The part of the PNS that controls involuntary actions of internal organs and glands.

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Neuron (Nerve Cell)

The basic unit of the nervous system, responsible for transmitting and processing information.

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Neuroglia (Glial Cells)

Supporting cells in the nervous system that protect and support neurons.

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Astrocytes

The most common type of glial cell in the CNS, responsible for maintaining the blood-brain barrier and providing structural support.

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Oligodendrocytes

Glial cells in the CNS that create myelin sheaths around axons, which speeds up nerve impulse transmission.

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Microglia

Glial cells in the CNS that act as immune cells, consuming debris and pathogens.

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Ependymal Cells

Glial cells in the CNS that line the central canal of the spinal cord and ventricles of the brain, producing and circulating cerebrospinal fluid.

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Satellite Cells

Glial cells in the PNS that surround neuron cell bodies in ganglia, providing protection and regulating the environment.

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Schwann Cells

Glial cells in the PNS that create myelin sheaths around axons, similar to Oligodendrocytes in the CNS.

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Myelin

A fatty substance that insulates axons, speeding up nerve impulse transmission.

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Synapse

The junction between two neurons, where communication occurs.

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Posterior (Dorsal) Ramus

A branch of a spinal nerve that carries sensory information from the back and motor commands to the back muscles.

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Anterior (Ventral) Ramus

A branch of a spinal nerve that carries sensory information from the front and sides of the body and motor commands to the front and sides.

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Rami Communicantes

Bundles of axons connecting spinal nerves to the sympathetic chain ganglia, primarily involved in the sympathetic nervous system.

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Dermatome

A specific area of skin supplied by sensory fibers from a single spinal nerve.

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White Matter

The part of the spinal cord containing myelinated axons, responsible for transmitting signals throughout the CNS.

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Grey Matter

The part of the spinal cord containing neuronal cell bodies, dendrites, and synapses, where information is processed.

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Dorsal Horn

The region of grey matter in the spinal cord receiving sensory information.

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Ventral Horn

The region of grey matter in the spinal cord sending motor commands.

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Reflex Arc

The pathway of a reflex, starting at a sensory receptor and ending at a peripheral effector.

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Monosynaptic Reflex

A reflex involving only one synapse between the sensory neuron and the motor neuron.

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What is a first-order neuron?

A sensory nerve that directly transmits sensations to the Central Nervous System (CNS).

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What is a second-order neuron?

An interneuron located in the spinal cord or brainstem that receives the message from the first-order neuron and passes it on.

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What is a third-order neuron?

A neuron that carries information to the conscious awareness in the cerebral cortex.

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What is decussation?

The point where the second-order neuron crosses to the opposite side of the CNS.

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What is the Homunculus?

A representation of the human body on the somatosensory cortex, with different body parts mapped proportionally to their sensitivity.

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What is the Spinothalamic pathway?

A somatic sensory pathway that carries sensations of pain, temperature, and crude touch to the CNS.

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What is the Posterior Column Pathway?

A somatic sensory pathway that carries sensations of fine touch, pressure, vibration, and proprioception to the CNS.

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What is the Spinocerebellar pathway?

A somatic sensory pathway that delivers proprioceptive information about muscle position and movement to the cerebellum.

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What is referred pain?

When pain experienced in a visceral organ is perceived as coming from a different, usually superficial, location.

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What is the Pain Gate Theory?

A theory that explains how certain stimuli can block or modulate pain signals traveling to the brain.

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What are association fibers?

Nerve fibers that connect different areas within the same hemisphere of the brain. They allow communication and coordination between various regions within a single hemisphere.

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What are commissural fibers?

Nerve fibers that connect the two hemispheres of the brain. They facilitate communication between the left and right brain, allowing for coordination and integrated function.

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What are projection fibers?

Nerve fibers that connect the cerebrum to other parts of the brain, including the spinal cord. They handle the flow of information between the cerebrum and the rest of the nervous system.

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What are the basal nuclei?

Clusters of gray matter deep within the cerebrum that play a crucial role in controlling and coordinating voluntary movements. They allow for smooth, coordinated movements.

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How does dopamine affect the basal nuclei?

Dopamine inhibits the activity of the basal nuclei, helping to control and regulate movements. A lack of dopamine can lead to movement disorders like Parkinson's disease.

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What is the primary somatosensory cortex?

The area of the cerebral cortex that receives sensory information from the body, allowing us to perceive touch, temperature, pain, and pressure.

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What is the primary motor cortex?

The area of the cerebral cortex that controls voluntary movements of the body, sending signals to muscles for contraction and coordination.

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What is Wernicke's area?

A region in the temporal lobe of the brain that plays a crucial role in understanding and interpreting spoken language.

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What is Broca's area?

A region in the frontal lobe of the brain that is important for speech production, allowing us to articulate and communicate our thoughts verbally.

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What is aphasia?

A language disorder that occurs due to damage to the language areas of the brain, affecting the ability to speak, write, and understand language.

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What is the cerebellum's role in movement?

The cerebellum is responsible for coordinating and refining voluntary movements, ensuring that they are smooth, precise, and balanced. It also helps maintain posture and equilibrium.

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What is the arbor vitae?

The white matter of the cerebellum, appearing as a tree-like structure. It carries information to and from the cerebellar cortex and nuclei.

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What is the thalamus's function?

The thalamus is a relay station for sensory information coming from the body and sends it to the appropriate areas of the cerebral cortex for processing. It acts as a gatekeeper, deciding what sensory information reaches conscious awareness.

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What are the main functions of the hypothalamus?

The hypothalamus plays a crucial role in regulating vital bodily functions, including body temperature, appetite, thirst, and the release of hormones.

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What is the limbic system?

A collection of brain structures that work together to regulate emotions, memory, and motivation. It plays a vital role in our experience of feelings and learning.

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What is the role of the midbrain?

The midbrain processes visual and auditory information, generates reflexive movements, and plays a crucial role in maintaining consciousness.

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What is the function of the pons?

The pons relays sensory information to the cerebellum and thalamus, controls some subconscious movements, and connects the midbrain and cerebellum.

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What is the medulla oblongata's function?

The medulla oblongata controls vital autonomic functions like breathing, heart rate, and digestion. It is also responsible for relaying motor information to the spinal cord.

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What are cranial meninges?

Three protective layers that surround and protect the brain and spinal cord. They provide structural support and cushioning for the delicate neural tissue.

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What is the dura mater?

The outermost layer of the meninges, a tough and fibrous membrane that is fused to the inside of the skull.

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What is the arachnoid mater?

The middle layer of the meninges, a delicate membrane that lies beneath the dura mater, containing the subarachnoid space filled with cerebrospinal fluid.

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What is the pia mater?

The innermost layer of the meninges, a thin and delicate membrane that closely adheres to the surface of the brain and spinal cord.

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What is cerebrospinal fluid (CSF)?

A clear, colorless fluid that circulates around the brain and spinal cord, providing cushioning, support, and transporting nutrients and waste products.

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What is the blood-brain barrier?

A protective barrier that isolates the central nervous system from the general circulation, regulating the passage of substances from the blood into the brain.

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What are cranial nerves?

12 pairs of nerves that originate in the brain and travel throughout the head and neck, controlling sensory and motor functions of the face, eyes, ears, tongue, and other structures.

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What are the two main divisions of the Autonomic Nervous System?

The Autonomic Nervous System (ANS) is divided into the Sympathetic Nervous System (SNS) and the Parasympathetic Nervous System (PNS).

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What is the function of the Sympathetic Nervous System?

The Sympathetic Nervous System (SNS) is responsible for preparing the body for 'fight or flight' responses, increasing alertness, and mobilizing energy resources.

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What is the function of the Parasympathetic Nervous System?

The Parasympathetic Nervous System (PNS) is responsible for 'rest and digest' functions, promoting relaxation, and conserving energy.

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What is the difference between preganglionic and postganglionic neurons in the ANS?

Preganglionic neurons have their cell bodies in the brain or spinal cord and extend to autonomic ganglia. Postganglionic neurons have their cell bodies in autonomic ganglia and extend to target organs.

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Where are preganglionic cell bodies located in the Sympathetic Nervous System?

Preganglionic cell bodies in the Sympathetic Nervous System are located in the T1-L2 segments of the spinal cord.

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Where are preganglionic cell bodies located in the Parasympathetic Nervous System?

Preganglionic cell bodies in the Parasympathetic Nervous System are located in four cranial nerves and the S2-S4 segments of the spinal cord.

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What are the three locations where sympathetic preganglionic neurons can synapse?

Sympathetic preganglionic neurons can synapse in the sympathetic chain ganglia, collateral ganglia, or the adrenal medulla.

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What is the role of the adrenal medulla in the Sympathetic Nervous System?

The adrenal medulla releases epinephrine and norepinephrine into the bloodstream, producing a widespread and long-lasting sympathetic response.

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What are the two main neurotransmitters involved in the ANS?

The two main neurotransmitters in the ANS are acetylcholine (Ach) and norepinephrine (NE).

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What are the two types of cholinergic receptors?

Nicotinic receptors are found on postganglionic neurons, while muscarinic receptors are found on effector organs.

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What is dual innervation in the ANS?

Dual innervation occurs when organs receive input from both the sympathetic and parasympathetic nervous systems, often with opposing effects.

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What are some exceptions to dual innervation in the ANS?

Arterioles, veins, most sweat glands, and salivary glands are exceptions, with only sympathetic innervation or both systems working together.

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What are visceral reflexes?

Visceral reflexes are automatic responses to stimuli that involve autonomic motor pathways and often involve feedback to higher brain centers.

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What is the difference between long reflexes and short reflexes in the ANS?

Long reflexes involve a pathway from sensory neurons to the CNS and back, whereas short reflexes are localized within a visceral organ and don't involve the CNS.

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What are the components of an autonomic reflex arc?

An autonomic reflex arc includes a receptor, sensory neuron, integrating center, motor neurons (preganglionic and postganglionic), and an effector.

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What is aqueous humor?

A fluid produced by the ciliary bodies in the eye. It nourishes the cornea and lens.

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What are tears?

A solution secreted by the lacrimal glands that cleans, lubricates, and protects the eye with lysosomes.

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What does the iris do?

The colored part of the eye that controls the amount of light entering the pupil.

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What is the pupil?

The round opening in the iris that allows light to enter the eye.

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What is accommodation?

The process of adjusting the lens's thickness to focus light on the retina.

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What is presbyopia?

The gradual loss of visual acuity with age.

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What is myopia?

Nearsightedness, where the eyeball is too long or the lens is too strong, blurry distant vision.

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What is hyperopia?

Farsightedness, where the eyeball is too short or the lens is too weak, blurry near vision.

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Where does vision processing start?

At the photoreceptors in the retina, where light stimuli are converted into neural signals.

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What is the optic chiasm?

The point where the optic nerves from each eye cross, sending information to the opposite side of the brain.

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What is the Reticular Activating System (RAS)?

A widespread network of neurons in the brainstem that regulates alertness, wakefulness, and consciousness.

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How does the RAS influence consciousness?

By stimulating the cerebral cortex, the RAS promotes cortical awareness and ends sleep. It also works with the thalamus to enhance focus.

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What happens if the RAS is inactive?

The RAS is inactive, the cerebral cortex slows down, leading to decreased function and eventually unconsciousness.

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How does aging affect the brain?

The brain shrinks, loses neurons, has decreased blood flow, and experiences changes in synaptic organization and cellular function.

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What are 'tangles' and 'plaques' in the aging brain?

Abnormal structures that form in the brain with age, potentially contributing to cognitive decline.

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How does aging affect brain function?

Aging can lead to difficulties with memory, decreased sensory acuity, slower reaction times, weakened reflexes, and decreased motor control.

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What is olfaction?

The sense of smell, detected by olfactory receptors in the nasal cavity.

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How do we smell?

Odorant molecules bind to olfactory receptors, triggering nerve impulses that travel to the olfactory cortex of the brain.

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What is the cribriform plate?

A part of the ethmoid bone that allows olfactory nerves to pass from the nasal cavity to the brain.

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What is gustation?

The sense of taste, detected by taste buds on the tongue.

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How do we taste?

Tastant molecules dissolve in saliva and interact with taste receptors in taste buds, sending signals to the gustatory cortex.

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What are the types of lingual papillae?

Vallate, foliate, fungiform, and filiform papillae are projections on the tongue that house taste buds.

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Why is the eye considered a fluid-filled sphere?

The eye is filled with two fluids - the aqueous humor and the vitreous humor. These help maintain the eye's shape and function.

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What are efferent pathways?

Efferent pathways carry motor commands from the CNS (brain and spinal cord) to the PNS (peripheral nervous system), directing muscle contractions and organ functions.

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What are the two types of efferent pathways?

The two main efferent pathways are the somatic motor pathways, controlling voluntary skeletal muscle movement, and the autonomic pathways, regulating involuntary actions of internal organs.

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What are exteroreceptors?

Exteroreceptors provide information about the external environment, like touch, temperature, and pain, from the surface of the body.

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What are proprioceptors?

Proprioceptors monitor the position and movement of skeletal muscles and joints, allowing for coordination and balance.

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What are interoceptors?

Interoceptors monitor internal organs and functions, like blood pressure and digestion, and usually don't reach conscious awareness.

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What is the difference between sensation and perception?

Sensation is the raw data received by sensory receptors, which may not be consciously recognized. Perception is the brain's interpretation and understanding of that sensory information.

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What is a receptive field?

A receptive field is the specific area monitored by a single sensory receptor.

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What is transduction?

Transduction is the conversion of a stimulus, like light, pressure, or chemical, into an electrical signal (action potential) that the nervous system can understand.

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What are nociceptors?

Nociceptors are pain receptors, responsible for detecting damaging or potentially harmful stimuli.

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What is the difference between tonic and phasic receptors?

Tonic receptors are constantly active, sending signals even in the absence of a stimulus. Phasic receptors are only active when a change occurs, then they adapt and become less sensitive.

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What is the pain pathway?

Pain signals travel through the nociceptors, spinal nerves, and up the spinothalamic tract to the thalamus and ultimately the somatosensory cortex for conscious perception.

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What are thermoreceptors?

Thermoreceptors are temperature receptors, detecting changes in temperature, either hot or cold.

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What are mechanoreceptors?

Mechanoreceptors respond to physical distortion, such as touch, pressure, vibration, and stretch.

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What are baroreceptors?

Baroreceptors are mechanoreceptors that detect changes in pressure, particularly within blood vessels.

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What are proprioceptors?

Proprioceptors are sensory receptors that provide information about the position and movement of the body, particularly in muscles and joints.

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What are chemoreceptors?

Chemoreceptors detect changes in the concentration of specific chemicals, mediating taste, smell, and internal monitoring.

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Study Notes

Nervous Tissue

  • Nervous system anatomical divisions: central nervous system (CNS) and peripheral nervous system (PNS)
  • Functional divisions: afferent (to CNS), efferent (from CNS), somatic nervous system (SNS), autonomic nervous system (ANS), enteric nervous system (GI tract)
  • Neurons: basic functional unit; responsible for information transfer and processing
  • Neuroglia (glial cells): supporting cells; protect and separate neurons

Neuroglia (Glial Cells) in the CNS

  • Astrocytes: most common, largest; maintain blood-brain barrier, provide structural support, regulate ions, nutrients, and gases, absorb neurotransmitters, form scar tissue
  • Oligodendrocytes: myelinate CNS axons, provide structural framework
  • Microglia: remove debris, wastes, and pathogens by phagocytosis; immune cell function
  • Ependymal cells: line central canal and ventricles; assist in producing, circulating, and monitoring cerebrospinal fluid (CSF)

Neuroglia (Glial Cells) in the PNS

  • Satellite cells: "astrocytes of PNS"; surround neuron cell bodies in ganglia; regulate oxygen, carbon dioxide, nutrients, and neurotransmitters
  • Schwann cells (neurolemmocytes): surround all axons in PNS; myelinate peripheral axons; participate in repair processes
  • Myelin: insulating layer for faster transmission; forms white matter
  • Nodes of Ranvier: gaps between Schwann cells

Neuron Classification

  • Anaxonic neurons: small, numerous dendrites, no obvious axons; found in brain and special sense organs
  • Bipolar neurons: two distinct processes (one dendrite and one axon); cell body between the two; rare; special sense organs
  • Unipolar (pseudounipolar) neurons: single elongated process; cell body off to the side; most sensory neurons in PNS; longest axon
  • Multipolar neurons: two or more dendrites and a single axon; most common in CNS

Functional Classification of Neurons

  • Sensory neurons (afferent fibers): send information from PNS to CNS; somatic (body) and visceral (organ) sensory neurons; interoceptors (digestive, respiratory, cardiovascular, urinary, and reproductive systems); exteroreceptors (external environment); proprioceptors (position and movement of skeletal muscles and joints)
  • Interneurons (association neurons): connect sensory and motor neurons; most neurons are interneurons

Synapse

  • Specialized site of neuron communication with another cell
  • Transmission from presynaptic cell to postsynaptic cell
  • Postsynaptic cell can be another neuron, muscle fiber, or gland cell
  • Two synapse types: electrical and chemical

Membrane Potential

  • Plasma membrane has a membrane potential (polarized electrically)
  • Separation of charges across the membrane; difference in cations and anions in intracellular and extracellular fluid (ICF and ECF)
  • Nerve and muscle cells are excitable tissues; undergo transient, rapid changes in membrane potential; fluctuations serve as electrical signals

Membrane Potential Terms

  • Resting membrane potential: membrane potential of a resting, unstimulated cell; typically -70 mV
  • Graded potentials: temporary, localized changes in resting potential; caused by stimulus; small signal; short range
  • Action potentials: electrical impulses produced by graded potentials; propagate along axon surface; large signal; long distance

Action Potential

  • Brief, rapid, and large (100 mV) change in membrane potential
  • Occurs in response to graded potentials that reach threshold
  • Essential for conduction of nerve impulses; demonstrates "all-or-none" principle

Steps in Action Potential

  • Depolarization to threshold (Sodium channels open)
  • Activation of voltage-gated sodium channels
  • Inactivation of sodium channels; activation of potassium channels
  • Closing of potassium channels and return to resting potential

Action Potential Characteristics

  • All-or-none law: stimuli bringing the membrane to threshold generate identical action potentials
  • No summation
  • Nondecremental: action potential amplitude remains the same throughout propagation
  • One-way propagation
  • Refractory period: absolute and relative periods

Propagation of Action Potential

  • Continuous propagation: unmyelinated fibers; action potential spreads along every portion of the membrane
  • Saltatory propagation: myelinated fibers; impulse jumps over myelin-covered sections

Electrical Synapse

  • Presynaptic and postsynaptic membranes linked by gap junctions
  • Ions pass between cells through pores; rapid potential propagation
  • Rare; found in retina and some parts of cerebral cortex, and ciliary ganglia

Chemical Synapses

  • Most common type of synapse between neurons, and the only type between neurons and other cells
  • Cells separated by synaptic cleft; presynaptic cell sends message, postsynaptic cell receives it
  • Neuromuscular junction: synapse between neuron and skeletal muscle cell
  • Neuroglandular junction: synapse between neuron and gland cell

Neurotransmitters

  • Chemical compounds released by one neuron to affect membrane potential of another
  • Released into synaptic cleft; exert effect on receptors in postsynaptic membrane; broken down by enzymes, reabsorbed

Neurotransmitter Release

  • Action potential reaches synaptic knob/terminal
  • Synaptic terminals become permeable to calcium ions, which diffuse inward
  • Synaptic vesicles fuse to terminal membranes
  • Release neurotransmitters into synaptic cleft
  • Synaptic vesicles re-enter axon cytoplasm to pick up more neurotransmitters

Classification of Neurotransmitters

  • Excitatory neurotransmitters: cause depolarization, promote action potential generation
  • Inhibitory neurotransmitters: cause hyperpolarization, suppress action potential generation

Major Classes of Neurotransmitters

  • Biogenic amines (norepinephrine, dopamine, serotonin)
  • Amino acids (glutamate, aspartate, glycine, GABA)
  • Neuropeptides (enkephalins, endorphins, dynorphins)
  • Dissolved gases (nitric oxide, carbon monoxide)

Postsynaptic Potential (PSP)

  • Response/change in membrane potential at postsynaptic membrane
  • Excitatory postsynaptic potential (EPSP): depolarization, promotes action potentials
  • Inhibitory postsynaptic potential (IPSP): hyperpolarization, suppresses action potentials

(Note: Subsequent sections on the central nervous system, spinal cord, brain, special senses, etc. are extremely detailed and would form a separate, even more comprehensive set of study notes.)

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Test your knowledge on the anatomy and functions of the nervous system, sensory organs, and related reflexes. This quiz covers essential topics necessary for understanding human physiology, including spinal cord functions and the physiology of sight and sound.

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