Nervous System and Special Senses Overview

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Questions and Answers

What are the two main divisions of the nervous system?

Central Nervous System and Peripheral Nervous System (correct)

Sympathetic and Parasympathetic

Afferent and Efferent

Somatic and Autonomic

Which type of neuroglial cell is responsible for forming the myelin sheath in the Central Nervous System?

Astrocytes

Microglial

Ependymal

Oligodendroglia (correct)

What is the main function of sensory neurons?

Transmit impulses for interpretation

Support the blood-brain barrier

Receive impulses from receptor sites (correct)

Produce a response to stimuli

What distinguishes a reflex arc from other neural pathways?

It provides immediate responses through the spinal cord Signup and view all the answers

Which of the following best describes the role of the autonomic nervous system?

Regulates involuntary body functions Signup and view all the answers

What type of neuron primarily transmits impulses for interpretation in the nervous system?

Interneurons Signup and view all the answers

What structure of a neuron is responsible for receiving signals from the environment?

Dendrites Signup and view all the answers

Which type of neuron is most often unipolar and involved in sensory functions?

Unipolar neurons Signup and view all the answers

What is the primary function of the medulla oblongata?

Connects the brain with the spinal cord Signup and view all the answers

Which lobe of the cerebrum is primarily responsible for processing visual information?

Occipital lobe Signup and view all the answers

What role do the pons varolii play in the brain?

Connects the spinal cord with parts of the brain Signup and view all the answers

What is the primary function of the hypothalamus?

Regulating homeostasis Signup and view all the answers

Which part of the brainstem is involved in reflex actions such as head and eyeball movement?

Midbrain Signup and view all the answers

What structure in the diencephalon serves as a relay station for sensory impulses?

Thalamus Signup and view all the answers

Which area of the cerebral cortex is responsible for interpreting sensory impulses?

Sensory areas Signup and view all the answers

What structure connects the two hemispheres of the cerebrum?

Corpus callosum Signup and view all the answers

What is the primary function of the reflex arc?

To provide an involuntary reaction to external stimuli Signup and view all the answers

Which of the following accurately describes gray matter in the central nervous system?

Contains nerve cell bodies and unmyelinated axons Signup and view all the answers

What is the role of the ventral root of a spinal nerve?

Carries motor impulses away from the spinal cord Signup and view all the answers

How many pairs of cervical spinal nerves are there?

8 pairs Signup and view all the answers

Which part of the brain is responsible for maintaining homeostasis?

Diencephalon Signup and view all the answers

What is one of the main structures in the brainstem?

Pons varolii Signup and view all the answers

Which protective structure surrounds the brain?

Both B and C Signup and view all the answers

What is the continuation of the medulla oblongata?

Spinal Cord Signup and view all the answers

What is the primary role of the cerebellum?

Coordinating muscular movements Signup and view all the answers

Which division of the Autonomic Nervous System is responsible for the body's fight or flight response?

Sympathetic Division Signup and view all the answers

Which neurotransmitter is primarily associated with the parasympathetic division?

Acetylcholine Signup and view all the answers

Which statement about the sense of smell is true?

Bipolar sensory neurons transfer the chemical impulse after it dissolves in nasal mucus. Signup and view all the answers

How does the sympathetic division affect digestion?

Inhibits digestive activities Signup and view all the answers

What role do tears play for the eyes?

Lubricate the eyes and contain protective enzymes Signup and view all the answers

What is required for gustatory perception to occur?

Chemical molecules dissolved in saliva Signup and view all the answers

What is the primary function of the vermis in the cerebellum?

Connect the two hemispheres for coordination. Signup and view all the answers

Study Notes

The Nervous System and Special Senses

The nervous system acts as the body's control center and communication network.
It directs the functions of body organs and systems.
It interprets the external environment.
It determines the body's reaction to changes.
Homeostasis, the balanced internal environment, is controlled by the nervous and endocrine systems.

Organization of the Nervous System

Central Nervous System (CNS): Includes the brain and spinal cord.
Peripheral Nervous System (PNS):
- Afferent Peripheral System:
  - Sensory neurons
- Efferent Peripheral System:
  - Somatic: Controls skeletal muscles
  - Autonomic: Controls involuntary functions (sympathetic and parasympathetic divisions).

Functional Organization of the PNS

Sensory (afferent) Division:
- Somatic Sensory:
  - General: Touch, pain, pressure, vibration, temperature, and proprioception in skin, body wall, and limbs.
  - Special: Hearing, equilibrium, vision
- Visceral Sensory:
  - General: Stretch, pain, temperature, chemical changes, and irritation in viscera; nausea and hunger
  - Special: Taste, smell
Motor (efferent) Division:
- Somatic Nervous System: Motor innervation of all skeletal muscles
- Autonomic Nervous System (ANS): Motor innervation of smooth muscle and glands (sympathetic and parasympathetic divisions)

Sympathetic and Parasympathetic Branches

Sympathetic Division ("Fight or Flight"): Mobilizes bodily resources in response to threat.
Parasympathetic Division ("Rest and Digest"): Replenishes bodily resources.

Neuroglial Cells

Astrocytes: Support, connection, blood-brain barrier
Oligodendrocytes: Support, myelin sheath formation (CNS)
Microglial: Phagocytosis
Ependymal: Line the ventricles of the brain
Schwann: Myelin sheaths in the peripheral nervous system

Structure of a Neuron

Cell body: Nucleus and metabolic center of the neuron.
Dendrites: Receive signals.
Axon: Extension of the cell body (conducts signals away).
Schwann cells: Produce myelin sheaths along the axon (important for efficient signal transmission).
Nodes of Ranvier: Gaps in the myelin sheath critical for saltatory conduction (faster signal transmission).

Classification of Neurons

Receptors: Detect environmental stimuli (unipolar).
Sensory Neurons: Receive impulses from receptors (unipolar).
Interneurons: Transmit impulses for interpretation and processing (multipolar).
Motor Neurons: React to the stimulus (multipolar).

The Reflex Arc

The pathway resulting in a reflexive action.
Receives a stimulus, enters the spinal cord (CNS), and produces an immediate response.
Examples include knee-jerk reflex, maintaining homeostasis, heartbeat, breathing, digestion, coughing, sneezing, swallowing, vomiting.
Involves sensory receptors, sensory neurons, interneurons, motor neurons, and effectors.

Grouping of Neural Tissue

White matter: Groups of myelinated axons that form nerve tracts within the CNS.
Gray matter: Nerve cell bodies, dendrites, and unmyelinated axon bundles.
Cortex: Gray matter on the surface of the brain
Nerve: A bundle of fibers outside the CNS
Ganglia: Nerve cell bodies outside the CNS
Tract: A bundle of fibers inside the CNS
Nucleus: Nerve cell bodies and dendrites inside the CNS
Horns: Areas of gray matter in the spinal cord.

The Spinal Cord

Continuation of the medulla oblongata.
Protected by meninges (dura mater, arachnoid, pia mater).
31 segments with spinal nerves.
It transmits sensory impulses to the brain and integrates reflexes, and is crucial for reflex actions and communication between the brain and the body via the spinal nerves

The Spinal Nerves

31 pairs, arising from the union of dorsal and ventral roots.
Mixed nerves, with both motor and sensory fibers.
Exit the vertebral column between vertebrae (named based on the cord segment they arise from)

The Brain

Divided into four main parts:
- Brainstem: Controls breathing, heartbeat, reactions to sensory stimuli.
- Diencephalon: Controls homeostasis.
- Cerebrum: Processes intellect, emotions, and sensory information.
- Cerebellum: Maintains body posture and balance.

Protection of the Brain

Cranial bones.
Meninges (protective membranes).
Cerebrospinal fluid (CSF).
Ventricles with the interventricular foramina.

The Four Major Lobes of the Brain

Frontal lobe: Muscle movements, moods, motivation.
Parietal lobe: Touch, pain, balance, taste, temperature.
Temporal lobe: Hearing, smell, memory, abstract thought, judgment.
Occipital lobe: Vision

Surface of the Cerebrum

Motor areas: Control muscular movements.
Sensory areas: Interpret sensory impulses.
Association areas: Process emotions and intellect.

The Cerebellum

Butterfly-shaped, second largest part of the brain.
Two partially separated hemispheres, connected by vermis.
Responsible for coordination of muscular movements, maintaining posture, and maintaining balance.

The Autonomic Nervous System

It's a subdivision of the efferent PNS.
It functions without conscious effort and regulates internal organ functions to maintain homeostasis
It regulates energy and activity levels of the body, responding in times of crisis by speeding up many functions, or dealing with normal, rest and digest activities through the parasympathetic division.
Sympathetic Division: Activates during stress or crisis. (fight or flight).
Parasympathetic Division: Promotes relaxation and recovery. (rest and digest).

The Special Sense

Smell: Inspired air molecules dissolved in nasal mucous trigger bipolar neurons to send impulses to the olfactory cortex in the brain.
Taste: Taste buds on the tongue, palate, and pharynx contain taste cells, sensitive to chemicals dissolved in saliva.
Sight: Eyes protected by eyelids and eyelashes. Tears lubricate and contain a bacteriolytic enzyme. The eyeball has various structures, including the sclera, choroid, and retina to send light signals to the brain
Hearing and Equilibrium: The outer ear collects sound waves, traveling to the middle ear (auditory ossicles to amplify), and then the inner ear, where the cochlea contributes to hearing, and the semicircular canals contribute to equilibrium.

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Description

Explore the intricacies of the nervous system and how it interacts with special senses. This quiz covers the central and peripheral nervous systems, their functions, and the importance of homeostasis. Test your knowledge on how sensory and motor pathways contribute to body responses and environmental interpretation.