PNS Anatomy and Physiology

These flashcards cover key terms and concepts in PNS anatomy and physiology, neurological pathophysiology, and therapeutic approaches in physical therapy.

Peripheral Nervous System (PNS)

Consists of the nerves leading to and from the CNS, including cranial nerves and spinal roots.

Cranial Nerves

12 pairs of nerves that arise from the brainstem responsible for various sensory and motor functions.

Peripheral Nerves

Nerves that connect the CNS functionally with the rest of the body through sensory and motor impulses.

Somatic Nervous System

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

Autonomic Nervous System (ANS)

Part of the PNS that controls involuntary functions such as heart rate and digestion.

Cervical Plexus

Network of nerves formed by the anterior rami of cervical nerves C1-C4 that innervate neck muscles.

Brachial Plexus

Network of nerves formed by C5-T1 that innervate the upper limb.

Lumbosacral Plexus

Network of nerves formed by the anterior rami of L1-S3 that innervate the pelvis and lower limbs.

Dermatome

Region of skin innervated by sensory fibers from a single spinal nerve.

Myotome

Group of muscles that a single spinal nerve root innervates.

Golgi Tendon Organ

Sensory receptor that detects tension in muscles.

Neural Plasticity

The brain's ability to adapt structurally and functionally in response to experience or injury.

Wallerian Degeneration

Regeneration process of a peripheral nerve after injury involving axon degeneration distal to the injury site.

Chromatolysis

Dissolution of Nissl bodies in the neuron’s cell body, indicative of injury.

Upper Motor Neuron Injury

Damage to the corticospinal tract resulting in spasticity and hyperreflexia.

Lower Motor Neuron Injury

Damage to anterior horn cells or peripheral nerves leading to flaccidity and muscle atrophy.

Neurapraxia

Mildest nerve injury with preserved axonal continuity and rapid recovery.

Axonotmesis

More severe nerve injury with damaged axons but preserved connective tissue; recovery is possible.

Neurotmesis

Most severe nerve injury with complete loss of nerve continuity; irreversible damage.

Bell's Palsy

Facial paralysis due to a lesion on cranial nerve VII.

Spinal Nerves

31 pairs of nerves that connect the spinal cord to the body, classified by cervical, thoracic, lumbar, sacral, and coccygeal.

Sensory Division

Part of the PNS that transmits sensory impulses to the CNS.

Motor Division

Part of the PNS that transmits motor impulses from the CNS to the effectors.

Sympathetic Nervous System

Part of the ANS that prepares the body for 'fight or flight' responses.

Parasympathetic Nervous System

Part of the ANS that conserves energy and promotes 'rest and digest' activities.

Cerebral Circulation

The blood supply to the brain essential for oxygen and glucose delivery.

Blood-Brain Barrier

Barrier that restricts the passage of substances from the bloodstream to the brain tissue.

Circle of Willis

An arterial ring at the base of the brain that provides collateral circulation.

Neuromuscular Junction

Synapse between a motor neuron and skeletal muscle fiber.

Pain Receptors

Nerves that respond to potentially damaging stimuli.

Oculomotor Nerve (III)

Cranial nerve responsible for eye movements and pupil constriction.

Facial Nerve (VII)

Cranial nerve responsible for facial expressions, taste, and salivation.

Vagus Nerve (X)

Cranial nerve that innervates the heart, lungs, and digestive tract.

Afferent Neurons

Neurons that carry sensory signals to the CNS.

Efferent Neurons

Neurons that carry motor signals from the CNS to muscles.

Phrenic Nerve

Nerve that innervates the diaphragm.

Sympathetic Chain Ganglia

Clusters of nerve cell bodies that are part of the sympathetic nervous system.

Endoneurium

Connective tissue surrounding individual axons in peripheral nerves.

Epineurium

Outer layer of connective tissue that surrounds an entire peripheral nerve.

Perineurium

Layer of connective tissue surrounding a bundle of nerve fibers.

Clinical Manifestations

Signs and symptoms observed in a clinical setting.

Scalene Muscles

Muscles located in the lateral neck region, innervated by the cervical plexus.

Hypoglossal Nerve (XII)

Cranial nerve responsible for tongue movements.

Accessory Nerve (XI)

Cranial nerve responsible for shoulder elevation and head rotation.

Trigeminal Nerve (V)

Cranial nerve responsible for sensation in the face and motor functions for chewing.

Vestibulocochlear Nerve (VIII)

Cranial nerve responsible for hearing and balance.

Glosso-pharyngeal Nerve (IX)

Cranial nerve responsible for taste and swallowing.

Accessory Gland Secretions

Fluid produced by glands innervated by the autonomic nervous system.

Sensation Testing Techniques

Methods like barognosis and graphesthesia used to assess sensory deficits.

Paresthesia

Abnormal sensation typically described as 'pins and needles'.

Neuropathic Pain

Pain caused by damage to the nervous system.

Intracranial Hypertension

Increased pressure within the skull.

Cerebrovascular Accident (Stroke)

Interruption of blood supply to the brain.

Cardiac Muscle

Involuntary muscle found in the heart, controlled by the ANS.

Homeostasis

The body's ability to maintain stable internal conditions.

Involuntary Muscle Control

Control exerted by the autonomic nervous system over smooth and cardiac muscles.

Reflex Arc

The neural pathway that controls a reflex action.

Motor End Plate

Specialized part of a muscle fiber membrane at the neuromuscular junction.

Somatic Reflections

Voluntary muscle control via spinal nerves.

Afferent fibers

Nerve fibers that carry sensory signals toward the CNS.

Efferent fibers

Nerve fibers that carry motor signals away from the CNS.

Cranial Ganglia

Clusters of nerve cell bodies associated with cranial nerves.

Sensory Cortex

Brain region responsible for processing sensory information.

MSW (Motor Sensory Weight)

Measurement used to quantify sensory and motor function.

Vasoconstriction

Narrowing of blood vessels, often in response to sympathetic nervous activity.

Vasodilation

Widening of blood vessels, often in response to parasympathetic nervous activity.

Acetylcholine (ACh)

Neurotransmitter used by the somatic and parasympathetic nervous systems.

Norepinephrine (NE)

Neurotransmitter used by the sympathetic nervous system.

Nervous System Impulses

Electrochemical signals that transmit information between neurons.

Motor neuron

A neuron that transmits impulses from the spinal cord to skeletal muscles.

Sensory neuron

A neuron that transmits sensory information to the spinal cord.

Hypothalamus

Brain region responsible for the regulation of autonomic functions.

Empirical Evidence

Information acquired by observation or experimentation.

Traction Injuries

Injuries caused by stretching or pulling on a nerve.

Compression Injuries

Injuries caused by pressure on a nerve.

Critical Thinking in Clinical Practice

The application of reflective reasoning and judgment in patient care.

Neuroscience Fundamentals

Basic principles that govern the structure and function of the nervous system.

Tissue Regeneration

The process by which damaged tissues heal and regenerate.

Pathophysiology of Neuromuscular Disorders

Study of how diseases affect the nervous system and muscle function.

Therapeutic Techniques in Physical Therapy

Interventions used by physical therapists to improve patient motor function.

Somatic Sensory Pathway

Pathway for transmitting sensory information from the body to the brain.

Spinal Cord Anatomy

The structure and function of the spinal cord as part of the CNS.

Neuroplasticity Reinforcement

The strengthening of synapses in response to learning and experience.

Hypoxic Conditions

Lack of sufficient oxygen supply to the tissues.

Glutamate Excitotoxicity

Cell damage caused by excessive stimulation by glutamate.

Excitatory Neurotransmitter

Substances that promote the firing of nerve impulses.

Limbic System Structures

Brain structures involved in emotional responses and memory.

Neurotransmitter Receptors

Molecules that receive signals from neurotransmitters.

Membrane Potential Changes

Alterations in the electrical potential across a cell membrane.

Cellular Edema

Swelling of cells due to fluid accumulation.

Glucose Demand

The requirement of glucose as fuel by neurons.

Oxygen Requirements

The necessity of oxygen for cellular metabolism, especially in neurons.

Behavioral Training in Recovery

Therapeutic activities designed to enhance patient recovery.

Brain Injury Assessment

Evaluation of impairments following brain injuries.

Cerebrovascular Disease

Medical conditions that affect blood flow to the brain.

Sympathetic Activation Responses

Physiological changes that occur during sympathetic nervous system activation.

Parasympathetic Activation Responses

Physiological changes that occur during parasympathetic nervous system activation.

Neural Injury Response

The body's immediate response to nerve damage.

Functional Independence Measure (FIM)

Assessment tool for measuring a patient's functional independence.

Quality of Life Indicators

Factors that determine a person's overall well-being.