Name: peripheral nervous system: signal pathways
Uploaded: 2025-06-13T09:17:31.000Z
Duration: 1 min 24 s
Channel: JoVE

K12 Standards

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Ohio’s Learning Standards and Model Curriculum

9-12

Human Anatomy and Physiology

Integration And Coordination

Nervous System

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Peripheral Nervous System: Ganglia and Nerves

The peripheral nervous system consists of nerves, ganglia, and sensory receptors.
Each nerve has an outermost connective tissue layer called the epineurium.
It collectively holds the blood vessels and the fascicles &#8212; collections of several parallel axons wrapped together by the perineurium.
Each fascicle contains an axon and its associated Schwann cells enclosed by a thin connective tissue known as the endoneurium.
Twelve pairs of such nerves, known as cranial nerves, originate from the brain, and 31 pairs of nerves, called the spinal nerves, originate from the spinal cord.
The PNS also contains ganglia &#8212;&#160; the collection of neuron cell bodies associated with nerves.
&#160;Based on their location and function, ganglia are of two major types.
The dorsal root ganglia, located along the spinal cord, are part of the sensory division of the PNS. They carry signals from peripheral receptors to the spinal cord.
The autonomic ganglia are associated with the motor division of the PNS. They are further divided into the sympathetic ganglia, present near the spinal cord, and the parasympathetic ganglia, present near the visceral organs.

peripheral nervous system: ganglia and nerves

The Peripheral Nervous System (PNS) is a crucial component of the body's neural network, extending beyond the central nervous system (CNS) to bridge the gap between the CNS and the external environment. It encompasses nerves, ganglia, and sensory receptors.
Nerves
The nerve is a bundle of axons that serves as the communication highway in the PNS. Each nerve is ensheathed in a protective layer of connective tissue called the epineurium. This outermost layer safeguards the nerve and supports the blood vessels supplying it. Within the nerve, axons are organized into smaller bundles called fascicles, each surrounded by the perineurium. This arrangement facilitates the efficient transmission of electrical signals along the axons. Encasing each axon and its Schwann cells is a delicate sheath called the endoneurium. This layered structure ensures a precise and protected transmission of nerve impulses across the PNS.
The PNS is functionally divided into two principal categories &#8212; the cranial and spinal nerves. The 12 pairs of cranial nerves have their origins in the brain. They are instrumental in various functions ranging from sensory input &#8212; such as vision, smell, and taste &#8212; to motor control, which includes facial expressions, eye movement, and speech.
On the other hand, the 31 pairs of spinal nerves emerge from the spinal cord, branching out to innervate the entire body. These nerves transmit sensory information from the limbs and trunk to the CNS and carry motor commands from the CNS to the muscles. Each spinal nerve is a mixed nerve, containing afferent (sensory) and efferent (motor) fibers, allowing for the bidirectional information flow between the CNS and the body.
Ganglia
Ganglia are clusters of neuron cell bodies located outside the CNS that are integral to the PNS's operation. They are categorized based on their location and the specific functions they perform.
The dorsal root ganglia, situated along the spinal cord, house the cell bodies of sensory neurons. They relay sensory information from peripheral receptors to the spinal cord, facilitating the sense of touch, pain, temperature, and proprioception.
The autonomic ganglia are associated with the motor division of the PNS. They play a key role in regulating involuntary functions, such as digestion, respiration, and heart rate. These ganglia are subdivided into sympathetic and parasympathetic ganglia, reflecting their roles in the body's fight-or-flight response and rest-and-digest activities, respectively. Sympathetic ganglia are positioned near the spinal cord, ready to mobilize the body's resources under stress. In contrast, parasympathetic ganglia are located close to visceral organs, overseeing the conservation and restoration of the body's energy.

The peripheral nervous system consists of nerves, ganglia, and sensory receptors.
Each nerve has an outermost connective tissue layer called the ...

Education

JoVE Core

Anatomy and Physiology

Unit 1

Anatomy of the Central and Peripheral Nervous System

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KEY TERMS AND CONCEPTS

peripheral nervous system: signal pathways

The peripheral nervous system links the central nervous system to the rest of the body. It includes nerves, ganglia, and sensory receptors. Together, these parts carry information between the brain, spinal cord, and the external environment.

Nerves are bundles of axons that act as communication routes in the peripheral nervous system. Each nerve has an outer connective tissue layer called the epineurium. This layer protects the nerve and supports the blood vessels that supply it. Inside the nerve, axons are grouped into fascicles, which are surrounded by the perineurium. Each axon and its Schwann cells are wrapped by the endoneurium, which helps keep nerve impulses organized and protected.

The peripheral nervous system includes cranial nerves and spinal nerves. There are 12 pairs of cranial nerves, and they begin in the brain. They help with sensory input such as vision, smell, and taste. They also control functions such as facial expressions, eye movement, and speech. The 31 pairs of spinal nerves come from the spinal cord and spread through the body. They carry sensory information from the limbs and trunk to the central nervous system and send motor commands from the central nervous system to muscles. Each spinal nerve is a mixed nerve, which means it contains both afferent (sensory) fibers and efferent (motor) fibers.

Ganglia are clusters of neuron cell bodies located outside the central nervous system. Dorsal root ganglia sit along the spinal cord and contain sensory neuron cell bodies. They carry sensory signals from peripheral receptors to the spinal cord. These signals help with touch, pain, temperature, and proprioception, which is the sense of body position.

Autonomic ganglia belong to the motor division of the peripheral nervous system. They help control involuntary functions such as digestion, respiration, and heart rate. Autonomic ganglia include sympathetic ganglia and parasympathetic ganglia. Sympathetic ganglia lie near the spinal cord and help the body respond to stress. Parasympathetic ganglia are close to visceral organs and support rest-and-digest activity, including energy conservation and restoration.

Peripheral Nervous System: Signal Pathways

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anatomy of the brain: major regions

Brain Regions and Their Main Functions

The human brain is the most complex organ in the body, and it is built from several major regions that work together. These regions include the cerebrum, diencephalon, cerebellum, and brainstem. Each part has a different role in how the brain processes information and controls the body. The cerebrum is the largest part of the brain. It is divided into left and right hemispheres by a deep fissure. Its outer layer is the cerebral cortex, which is gray matter. The cortex has raised folds called...

anatomy of the brain: ventricles

Brain Ventricles and Cerebrospinal Fluid

Brain ventricles are hollow, fluid-filled cavities deep inside the human brain. They hold cerebrospinal fluid, or CSF, which helps protect the central nervous system and supports neural signaling. The two lateral ventricles sit in the cerebral hemispheres, one on each side. Each lateral ventricle has three visible projections from the side: the anterior horn, the inferior horn, and the posterior horn. A thin membrane called the septum pellucidum separates the left and right lateral ventricles.<br...

cerebrum: anatomical overview i

Cerebrum: Lobes and Brain Folds

The cerebrum is the largest part of the human brain. It has an outer cerebral cortex, which is the wrinkled surface with folds called gyri and shallow grooves called sulci. Beneath the cortex is a deeper region inside each hemisphere. The cerebrum is divided into two hemispheres and five lobes. These lobes are the frontal, parietal, temporal, occipital, and insula lobes. The insula is the smallest lobe, and it lies deep within the lateral sulcus. Several sulci help separate the lobes and...

cerebrum: anatomical overview ii

Cerebrum Regions and Fiber Tracts

The cerebrum is organized into three main regions within each cerebral hemisphere. The outermost region is the cerebral cortex. It is a thin gray matter layer, about 2 to 4 millimeters thick, and it contains neuron cell bodies, dendrites, glial cells, and blood vessels. Beneath the cortex is the white matter. This middle region is mostly made of myelinated nerve fibers. These fibers form three large tract types: association fibers, commissures, and projection fibers. Association fibers...

motor and sensory areas of the cortex

How the Cortex Controls Senses and Movement

The cerebral cortex controls voluntary movement and processes sensory information. It is the brain's outermost layer and also helps with complex thinking, emotions, learning, and memory. Its main functional areas are the motor areas, sensory areas, and association areas. The motor areas are in the frontal lobe and control body movement. They include the primary motor cortex and the premotor cortex. The primary motor cortex is in the precentral gyrus and sends signals to skeletal muscles. It is...

association areas of the cortex

Brain Areas for Language and Attention

Association areas in the cerebral cortex help the brain combine information and make sense of it. Unlike regions with one clear sensory or motor job, these areas support memory, learning, and decision-making. They work by linking signals from multiple parts of the brain. The prefrontal association area sits in the frontal lobe. It helps with planning, decision-making, and social behavior. It also connects with primary motor areas, sensory areas, and the limbic system, which handles emotions. <br...

diencephalon: anatomical regions

Diencephalon Functions and Connections

The diencephalon links the cerebrum with the rest of the nervous system. The term means “through brain,” and the region sits deep beneath the cerebrum. The olfactory system is an exception because it connects directly with the cerebrum. The diencephalon mainly includes the thalamus, hypothalamus, and epithalamus. It also contains the subthalamus, which includes the subthalamic nucleus as part of the basal nuclei. The thalamus acts as a major relay and processing center. It contains many...

diencephalon: thalamus and information relay

diencephalon-thalamus-and-information-relay

Thalamus: Relay Centers of the Brain

The thalamus is the brain’s main relay center for sensory and motor signals. It is often called the gateway to the cerebral cortex because most information headed there passes through it. Olfactory signals are the main exception. The thalamus also helps filter incoming signals and can give priority to some inputs based on the body’s current needs. The thalamus is made of several paired nuclei, or small groups of nerve cells with specific jobs. The anterior nucleus carries information from the...

diencephalon: hypothalamus and coordination

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Hypothalamus: Brain Control and Body Balance

The hypothalamus is a small brain region that helps control many body functions. It sits at the base of the brain, above the brainstem and below the thalamus. It is part of the limbic system and connects directly with the pituitary gland through the hypothalamic-pituitary axis. The hypothalamus receives somatic inputs from the body and visceral inputs from internal organs. It uses this information to regulate important physiological activities. The region is divided into four parts:...

cerebellum: anatomical regions

Cerebellum Structure and Pathways

The cerebellum is a brain region that helps control movement, coordination, and proprioception. It lies in the posterior cranial fossa, below the tentorium cerebelli and behind the brainstem. Because of its role in motor control, it is often called the "little brain." The outer surface of the cerebellum is highly folded. It has many folia, or narrow ridges, separated by shallow sulci, or grooves. A thin midline part called the vermis divides the cerebellum into two hemispheres and helps...

brainstem

Brainstem Pathways and Life Functions

The brainstem links the brain to the spinal cord and helps control vital body functions. It sits below the brain and above the spinal cord. The brainstem has three parts: the midbrain, pons, and medulla oblongata. The midbrain lies below the diencephalon and connects the cerebrum with the lower brain regions. Its cerebral peduncles contain the crus cerebri, which hold the corticospinal tract. This tract carries signals from the cerebral cortex to the spinal cord, so it supports voluntary...

brainstem: control centers of medulla

Medulla Nuclei and Autonomic Control

The medulla oblongata is a key part of the brainstem that helps control involuntary body functions. It contains several nuclei, or clusters of nerve cells, including the olivary, cuneate, gracile, and solitary nuclei. These structures support movement, sensation, breathing, and other vital activities. The olivary nucleus, also called the inferior olivary nucleus, sits in the ventrolateral medulla. It helps with motor coordination and motor learning. It receives input from the spinal cord,...

functional brain systems: limbic system

Limbic Brain Regions and Their Functions

The limbic system is a deep brain network linked to emotion, memory, and sensory processing. It is often called the emotional brain because it helps connect higher mental functions of the cerebral cortex with older emotional responses from deeper brain structures. This functional region includes parts of the diencephalon and the cerebrum. The limbic lobe includes three main gyri: the cingulate gyrus, the parahippocampal gyrus, and the subcallosal gyrus. The cingulate gyrus lies on the medial...

functional brain systems: reticular formation

functional-brain-systems-reticular-formation

Reticular Formation and the Brainstem RAS

The reticular formation is a network of gray and white matter in the brainstem. It extends from the medulla to the midbrain. Its nuclei are grouped into three main regions: raphe nuclei, medial nuclei, and lateral nuclei. The raphe nuclei lie along the midline of the brainstem. They are best known for making and releasing serotonin, a neurotransmitter that helps regulate mood, appetite, sleep, and circadian rhythms. The medial nuclei sit near the center of the reticular formation. They help...

spinal cord: gross anatomy

Spinal Cord Pathways and Protection

The spinal cord carries signals between the brain and the body. It sits inside the vertebral column, where the bones help protect it. It also supports reflexes and helps control complex motor movements. The spinal cord begins at the medulla oblongata, which is at the base of the brainstem. It extends downward and ends at the conus medullaris near the first and second lumbar vertebrae. In adults, the spinal cord is about 45 cm, or 18 inches, long. That is much shorter than the vertebral column,...

spinal cord: cross-sectional anatomy

Spinal Cord Gray and White Matter

The spinal cord cross section shows how gray matter and white matter are arranged inside the central nervous system. In the middle, gray matter forms a butterfly or H shape. White matter surrounds it. The dorsal median sulcus and the ventral median fissure divide the cord into left and right halves. At the center of the gray matter is the gray commissure. It surrounds the central canal, which contains cerebrospinal fluid, or CSF. The gray commissure connects the left and right sides of the...

spinal cord: information processing

Spinal Cord Sensory and Motor Pathways

The spinal cord carries sensory signals and motor commands between the brain and the peripheral nervous system (PNS). It acts as a major relay center that helps the brain communicate with the body. In this pathway, sensory input travels upward and motor output travels downward. Sensory processing begins at receptors in the skin and other tissues. These sensory receptors detect somatic stimuli such as touch, temperature, and pain. They trigger nerve impulses that move toward the spinal cord...

The peripheral nervous system links the central nervous system to the rest of the body. It includes nerves, ganglia, and sensory receptors. Together, these parts carry information between the brain, spinal cord, and the external environment. Nerves are bundles of axons that act as communication routes in the peripheral nervous system. Each nerve has an outer connective tissue layer called the epineurium. This layer protects the nerve and supports the blood vessels that supply it. Inside the...

cranial nerves: overview and anatomy

Cranial Nerves and Their Functions

Cranial nerves are 12 pairs of nerves that connect the brain to the head and neck. They carry signals between the brain and the body. Each pair is numbered with Roman numerals from I to XII, starting at the front of the brain and moving toward the back. Each nerve also has a name that reflects its function or the structure it serves. These nerves are grouped as sensory, motor, or mixed nerves. Sensory nerves detect information from the environment. Motor nerves control muscle movement. Mixed...

cranial nerves: types part i

Cranial Nerves I-VI: Eye and Face Control

Cranial nerves I through VI carry sensory and motor signals between the brain and the head and neck. The first six pairs help with smell, vision, eye movement, facial sensation, chewing, and some autonomic functions. They are key to everyday tasks like noticing odors, seeing, and moving the eyes together. The olfactory nerve, or cranial nerve I, is a purely sensory nerve for smell. It begins in the olfactory epithelium of the nasal cavity and connects to the olfactory bulb in the brain. If...

cranial nerves: types part ii

Cranial Nerves VII-XII Functions

Cranial nerves VII through XII carry motor and sensory signals between the brain and the body. These six pairs help with facial movement, hearing, balance, swallowing, speech, and control of organs in the chest and abdomen. They also support communication, expression, and autonomic control. The facial nerve, cranial nerve VII, is a mixed nerve. It controls facial expressions and carries taste from the anterior two-thirds of the tongue. It also helps control the lacrimal glands and salivary...

spinal nerves: anatomy

Spinal Nerves and Body Signals

Spinal nerves carry signals between the spinal cord and the rest of the body. They connect the central nervous system and the peripheral nervous system, which lets the body send sensory input, motor output, and autonomic signals. There are 31 pairs of spinal nerves, and each pair leaves the spinal cord through an intervertebral foramen, the opening between two vertebrae. These nerves are organized by region of the spine. The 8 cervical nerves are C1 through C8, the 12 thoracic nerves are T1...

spinal nerves: plexus i

Spinal Nerve Plexuses of the Neck and Arm

Spinal nerve plexuses are networks of interlacing nerves that organize nerve signals across the body. They act as communication hubs and are grouped into the cervical plexus in the neck, the brachial plexus in the shoulder area, the lumbar plexus in the lower back, the sacral plexus in the pelvis, and the coccygeal plexus in the coccyx region. The cervical plexus is formed by the anterior rami of the first four cervical spinal nerves, C1 to C4, with some input from C5. It lies in the neck...

spinal nerves: plexus ii

Lower Body Nerve Plexuses

The lower body nerve plexuses include the lumbar, sacral, and coccygeal plexuses. These nerve networks carry sensory information and help control motor function in the abdomen, pelvis, legs, and coccygeal region. The lumbar plexus sits in the lower back. It is mainly formed by the first four lumbar spinal nerves, L1 through L4. Its branches include the iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, femoral, and obturator nerves. These nerves send signals to the...

cranial and spinal meninges

Protective Layers Around the CNS

The cranial and spinal meninges are protective layers around the central nervous system, or CNS. The CNS includes the brain and spinal cord. These membranes help support the CNS, protect it, and help move cerebrospinal fluid, or CSF. The cranial meninges cover the cranium. The outermost layer is the dura mater, a thick membrane made of dense collagen fibers. It has two layers. The periosteal layer attaches to the inner surface of the skull, and the meningeal layer lies beneath it. The cranial...

cerebrospinal fluid

CSF Pathway and Brain Protection

Cerebrospinal fluid, or CSF, is a colorless liquid that surrounds the brain and spinal cord. It supports the central nervous system, or CNS, and helps it work properly. CSF production, flow, and absorption are tightly controlled. Most CSF is made in the choroid plexus, a network of capillaries and ependymal cells in the brain’s ventricular system. An adult usually has about 125 to 150 mL of CSF, but about 500 mL is made each day. That means the full amount is replaced about every 5 to 6 hours.

key terms and concepts

Explore how nerves, ganglia, and sensory receptors connect the brain and spinal cord to the body, including cranial nerves, spinal nerves, and autonomic control.

Peripheral Nervous System: Signal Pathways | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

Alabama Course of Study Science

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From Molecules to Organisms: Structures and Processes

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Florida Department of Education

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SC.912.L.14

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Organization of the Nervous System

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Functional Divisions of the Nervous System

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Functions of the Nervous System

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Neurons: The Cell Body and the Dendrites

A typical nerve cell comprises three main components: the cell body, dendrites, and the axon. The cell body, also known as the soma or perikaryon, serves ...

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Nervous Tissue: Neuron Types

Neurons, the fundamental units of the nervous system, can be classified based on both their structural and functional characteristics.
Structurally, ...

Nervous Tissue: Glial Cells

Glial cells or neuroglia are non-neuronal cells in the nervous system that outnumber neurons. These include astrocytes, oligodendrocytes, microglia, and ...

Nervous Tissue: Myelin

Myelin is a protective, multilayered covering around axons, composed of lipids and proteins, that provides electrical insulation.
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Electrochemical Gradient and Channel Proteins: An Overview

An electrochemical gradient is a fundamental concept in biology and chemistry. It regulates the movement of ions across cell membranes. This movement is ...

Ligand-gated Ion Channels

Voltage-gated Ion Channels

Mechanically-gated Ion Channels

Resting Membrane Potential

Resting Potential Decay

Graded Potential

Graded potentials are localized fluctuations in the cell membrane&#39;s electrical charge, commonly found in the dendrites of neurons. The magnitude of ...

Action Potential: Phases of Stimulation

The action potential is a complex electrical event that occurs in excitable cells, such as neurons and muscle cells. It consists of several distinct ...

Anatomy of the Brain: Major Regions

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The cerebrum ...

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Deep inside the human brain are the hollow fluid-filled cavities called ventricles.
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The cerebrum is the largest part of the brain. It is divided into two cerebral hemispheres.
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Cerebrum: Anatomical Overview II

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Neurotransmitters

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Motor and Sensory Areas of the Cortex

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Postsynaptic Potential (PSP)

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neurogenesis-and-regeneration-of-nervous-tissue

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Nervous System

Content elaboration: The nervous system consists of neurons and supporting cells that combine to form nerves, the spinal cord and the brain. The primary functions of the nervous system are sensation, integration and response. A comparison of the structures and functions of the central and peripheral nervous systems should be explored. The central nervous system is composed of the brain and spinal cord. The peripheral nervous system includes the remaining nervous tissue. A neuron consists of dendrites, a cell body and an axon. Neurons conduct electrical impulses along their membranes and at synapses. Brain cells can detect and sometimes respond to these impulses. Neuroglial cells help to support neural function. The brain consists of three major parts: the cerebrum, cerebellum and brainstem. The cerebrum is divided into lobes and hemispheres. Functions of the cerebrum that may be explored include voluntary muscle control, memory, sensory perception, emotions and speech. The cerebellum is primarily responsible for balance and coordination. The brainstem, a part of the autonomic nervous system, includes structural divisions that perform basic life functions such as breathing and heart rate. The spinal cord is a continuation of the brainstem. The spinal cord is a bundle of nerve tracts that transmits nerve signals between the brain and the body through electrical impulses. Nerves are bundles of neurons that transmit impulses between the peripheral and central nervous systems. The study of nerves can include sciatic, cranial and spinal nerves. Supporting structures of the central nervous system include the meninges and cerebrospinal fluid which protect the central nervous system. Processes of the nervous system are action potential propagation, simple nerve pathways (reflex arc) and neurotransmitter function. Homeostatic imbalances are explored. These include, but are not limited to, the effects of drugs, mental illnesses, spinal injuries, concussions, meningitis and multiple sclerosis (MS). Investigations are used to understand and explain the nervous system in a variety of inquiry and design scenarios that can incorporate evolutionary concepts, scientific reasoning, comparative analysis, communication skills and real-world applications.

Peripheral Nervous System: Signal Pathways

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