Pathophysiology - Pain, Temperature, Sleep, Sensory, and Cognitive Alterations

Flashcards covering the pathophysiology of pain, thermoregulation, sleep, sensory function, and cognitive/motor alterations based on lecture notes.

Homeostasis

The state of body balance maintained by core systems such as pain, temperature regulation, sleep, and sensory function, primarily controlled by the nervous system.

Nociceptors

Specialized sensory receptors located in skin, muscles, joints, blood vessels, and visceral organs that respond to mechanical injury, thermal injury, and chemical mediators.

A-delta fibers

Fast, myelinated nerve fibers responsible for transmitting sharp, well-localized pain sensations.

C fibers

Slow, unmyelinated nerve fibers responsible for transmitting dull, aching, and diffuse pain sensations.

Transduction

The first phase of pain where a harmful stimulus is converted into an electrical signal at the nociceptor.

Transmission

The second phase of pain where the electrical impulse travels from peripheral nerves through the spinal cord toward the brain.

Perception

The third phase of pain where it becomes a conscious experience shaped by emotion, culture, and psychology.

Modulation

The fourth phase of pain where descending pathways and neurotransmitters (such as GABA or endorphins) amplify or suppress the pain signal.

Substance P and Glutamate

Excitatory neurotransmitters involved in the modulation phase of pain that amplify the signal.

Somatic pain

A type of acute pain characterized as sharp or aching and which is well localized.

Visceral pain

A type of acute pain characterized as deep, cramping, and poorly localized.

Neuropathic pain

Pain described as burning, shooting, or tingling, resulting from nerve injury such as in diabetic neuropathy.

Referred pain

Pain felt at a location away from the actual source, such as left arm pain during a myocardial infarction, due to converging visceral and somatic pathways.

Nociplastic pain

Pain resulting from altered processing without clear tissue injury, such as in fibromyalgia.

Hypothalamus

The part of the brain that acts as the thermostat for thermoregulation and also helps regulate the sleep-wake cycle.

Fever

A regulated increase in the hypothalamic set point caused by pyrogens, which involves the body intentionally generating and conserving heat.

Hyperthermia

A failure of heat dissipation where the body temperature rises without a change in the hypothalamic set point.

Hypothermia

A condition where the core temperature falls below $35^{\circ}C$, leading to CNS depression and slowed metabolism.

NREM sleep

Sleep stage characterized by decreased metabolic activity and heart rate, playing a major role in physical restoration.

REM sleep

Sleep stage making up roughly $20-25\%$ of sleep time, featuring vivid dreaming, high brain activity, and muscle relaxation.

Anosmia

The loss of the sense of smell, which reduces environmental awareness.

Proprioception

The body's ability to remain oriented in space; its loss increases the risk of falls.

Arousal

The wakefulness component of consciousness, heavily dependent on the brainstem and the reticular activating system.

Awareness

The component of consciousness reflecting the cortical ability to perceive, interpret, think, and respond.

Locked-in syndrome

A condition where a patient is conscious but cannot move or communicate due to ventral pontine damage.

Aphasia

A cognitive disorder that impairs language production and/or comprehension.

Agnosia

A cognitive disorder characterized by the inability to recognize objects despite intact sensation.

Delirium

An acute, fluctuating, and often reversible state of confusion usually caused by infection, medication, or metabolic derangement.

Dementia

A progressive and usually irreversible decline in cognition reflecting chronic neurodegeneration or vascular injury.

Alzheimer disease

The most common cause of dementia, associated with the presence of amyloid plaques and neurofibrillary tangles.

Vasogenic edema

Brain swelling caused by blood-brain barrier disruption that allows fluid to leak into the extracellular space.

Cytotoxic edema

Brain swelling caused by fluid accumulation within injured neurons.

Hydrocephalus

A condition involving excess cerebrospinal fluid (CSF) within the ventricular system, which increases intracranial pressure.

Upper Motor Neuron (UMN) signs

Clinical patterns including spasticity, increased muscle tone, and hyperreflexia.

Lower Motor Neuron (LMN) signs

Clinical patterns including flaccid paralysis, decreased muscle tone, and hyporeflexia.

Parkinson disease

A movement disorder caused by dopamine deficiency, resulting in tremors and slowed movement.

Huntington disease

An inherited neurodegenerative disorder characterized by excessive involuntary movement.

Multiple sclerosis

An autoimmune attack on CNS myelin causing episodic weakness, sensory changes, and visual symptoms.

Guillain-Barré syndrome

An acute inflammatory peripheral neuropathy that results in ascending paralysis.

Myasthenia gravis

A neuromuscular junction disorder where antibodies attack acetylcholine receptors, causing fatigable weakness that often affects the eyes and swallowing first.