cough reflex

Examples of cough reflex in the following topics:

• Larynx

  • The larynx (plural: larynges), commonly called the voice box, is an organ in the neck of humans and most animals that is involved in breathing, sound production, coughing, and protecting the trachea against food aspiration during eating.
  • The larynx closes off during coughing to help prevent harmful gasses from entering the lungs.
  • During a cough reflex, air is forced out of the lungs, which can remove accumulated mucus, fluid, or blood from the lungs during injury, infection, or cancer of the lungs, as well as food or objects in the trachea during choking.

• Neural Mechanisms (Respiratory Center)

  • The medulla also controls the reflexes for nonrespiratory air movements, such as coughing and sneezing reflexes, as well as other reflexes, like swallowing and vomiting.

• Autonomic Reflexes

  • Autonomic reflexes are unconscious motor reflexes relayed from the organs and glands to the CNS through visceral afferent signaling.
  • An example of referred pain from an autonomic reflex arc occurs when the bowel is suddenly distended.
  • The medulla's major ANS functions include respiration (the respiratory control center, or RCC), cardiac regulation (the cardiac control center, or CCC), vasomotor activity (the vasomotor center or VMC), and certain reflex actions (such as coughing, sneezing, vomiting and swallowing).
  • General visceral afferent sensations are mostly unconscious, visceral motor reflex sensations from hollow organs and glands that are transmitted to the CNS (see the following illustration for a depiction of a typical nerve fiber, including general visceral afferent fibers).
  • While the unconscious reflex arcs are normally undetectable, in certain instances they may send pain sensations to the CNS, masked as referred pain.

• Control of Autonomic Nervous System Function

  • The medulla's main functions are to control the cardiac, respiratory, and vasomotor centers, to mediate autonomic, involuntary functions, such as breathing, heart rate, and blood pressure, and to regulate reflex actions such as coughing, sneezing, vomiting, and swallowing.

• Vomiting

  • Under normal circumstances the gag reflex and coughing prevent this from occurring; however, these protective reflexes are compromised in persons under the influences of certain substances such as alcohol or anesthesia.
  • If the vomiting reflex continues for an extended period with no appreciable vomitus, the condition is known as non-productive emesis or dry heaves, which can be painful and debilitating.

• Reflexes and Diagnosis

  • A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus.
  • Scientific use of the term "reflex" refers to a behavior that is mediated via the reflex arc; this does not apply to casual uses of the term "reflex".
  • Generally, decreased reflexes indicate a peripheral problem, and lively or exaggerated reflexes a central one.
  • While the reflexes above are stimulated mechanically, the term H-reflex refers to the analogous reflex stimulated electrically, and Tonic vibration reflex for those stimulated to vibration.
  • While 2+ is considered normal, some healthy individuals are hypo-reflexive and register all reflexes at 1+, while others are hyper-reflexive and register all reflexes at 3+.

• Gastrointestinal Reflex Pathways

  • The digestive system functions via a system of long reflexes, short reflexes, and extrinsic reflexes from gastrointestinal (GI) peptides working together.
  • In addition, there are three overarching reflexes that control the movement, digestion, and defecation of food and food waste: the enterogastric reflex, the gastrocolic reflex, and the gastroileal reflex.
  • When this occurs, it is called a short reflex.
  • The gastrocolic reflex is the physiological reflex controlling the motility, or peristalsis, of the gastrointestinal tract.
  • The gastroileal reflex is a third type of gastrointestinal reflex.

• Components of a Reflex Arc

  • A reflex arc defines the pathway by which a reflex travels—from the stimulus to sensory neuron to motor neuron to reflex muscle movement.
  • The path taken by the nerve impulses in a reflex is called a reflex arc.
  • There are two types of reflex arcs:the  autonomic reflex arc, affecting inner organs, and the somatic reflex arc, affecting muscles.
  • For example, the withdrawal reflex (nociceptive or flexor withdrawal reflex) is a spinal reflex intended to protect the body from damaging stimuli.
  • The path taken by the nerve impulses in a reflex is called a reflex arc.

• Spinal Reflexes

  • Spinal reflexes include the stretch reflex, the Golgi tendon reflex, the crossed extensor reflex, and the withdrawal reflex.
  • Spinal reflexes include the stretch reflex, the Golgi tendon reflex, the crossed extensor reflex, and the withdrawal reflex.
  • This reflex has the shortest latency of all spinal reflexes.
  • Like the stretch reflex, the tendon reflex is ipsilateral.
  • The crossed extensor reflex is a withdrawal reflex.

• Syncope

  • There are two broad categories of syncope, cardiogenic or reflex, which underlie most forms of syncope.
  • Variants of reflex syncope often have characteristic histories, including precipitants and time course which are made evident by skilled history taking.
  • Vasovagal (situational) syncope, one of the most common types, may occur in scary, embarrassing or uneasy situations, or during blood drawing, coughing, urination or defecation.