Trigeminal Reflexes and Cardiovascular Function

Nervous system connections between the trigeminal nerve and the heart that rapidly change heart function.

A specific trigeminal reflex, primarily related to heart function during water immersion.

Another specific trigeminal reflex, connecting facial stimulation to changes in heart function.

Connections between body sensations (somatosensory) and automated bodily functions (autonomic).

How the heart's actions are controlled, including the sympathetic and parasympathetic nervous systems.

Part of the autonomic nervous system involved in 'fight-or-flight' responses.

Part of the autonomic nervous system promoting 'rest-and-digest' actions.

The heart receives signals from both the sympathetic and parasympathetic systems, allowing complex responses.

A variation of the diving reflex activated by stimulation of the nasal mucosa (nose and throat). It also reduces heart rate and blood flow to peripheral tissues.

A nerve connection between the trigeminal nerve (facial sensations) and the vagus nerve (heart control), leading to rapid changes in heart function.

A nerve in the nasal passages that plays a key role in activating the nasopharyngeal reflex.

Narrowing of blood vessels, reducing blood flow to a specific area.

While the diving reflex is present in both humans and diving animals, the intensity of its effects (especially the sympathetic response) varies significantly.

Anesthetics can influence the effectiveness of trigeminal-vagal reflexes, making them more unpredictable.

The level of activity in the sympathetic nervous system.

Opposition to blood flow through blood vessels away from the heart.

Opposition to blood flow in the carotid arteries, supplying blood to the brain.

Variations in blood pressure caused by trigeminal reflexes.

Problems that arise in the heart due to trigeminal reflexes.

Complete absence of heart electrical activity.

Chaotic and ineffective quivering of the heart's ventricles.

Sudden narrowing of the coronary arteries, reducing blood flow to the heart muscle.

A slowing of heart rate triggered by immersing the face in cold water. This is a key component of the diving reflex.

Both maxillary and mandibular nerve stimulation can trigger the trigeminocardiac reflex, but the responses might be different.

The pathway of the trigeminocardiac reflex involves the trigeminal nerve, brainstem, and vagus nerve, leading to rapid heart rate changes.

The diving reflex involves increasing sympathetic activity, which constricts blood vessels and conserves oxygen.

A type of local anesthetic injection used to block the trigeminal nerve, potentially affecting the trigeminocardiac reflex.

Anesthetics can alter the trigeminocardiac reflex, making it weaker or even unpredictable.

Stimulating branches of the trigeminal nerve can induce a variety of physiological changes, including a sharp decrease in heart rate, lowered blood pressure, apnea (temporary cessation of breathing), and increased stomach motility.

Low frequency stimulation of the trigeminal nerve leads to tachypnea (rapid breathing), while higher intensity stimulation results in expiratory apnea (holding your breath after exhaling).

A classic example of a trigeminal reflex, where pressing on the eyeballs causes a significant decrease in heart rate.

The sympathetic nervous system, responsible for 'fight-or-flight' responses, can be activated by trigeminal reflexes, leading to increased heart rate and blood pressure. The parasympathetic nervous system, responsible for 'rest-and-digest' responses, is often activated, leading to decreased heart rate and increased digestive activity.

Trigeminal reflexes can significantly impact cardiovascular control by modifying heart rate, blood pressure, and blood flow distribution. They can lead to rapid changes in these cardiovascular functions, depending on the nature and intensity of the stimulus.

While the trigeminal reflexes show similarities across species, there are variations in their strength and the degree of involvement of the sympathetic nervous system, particularly in diving mammals.

General anesthesia can influence the intensity and predictability of trigeminal reflexes. It can complicate the interpretation of these reflexes during medical procedures.