The internal anal sphincter is governed by involuntary control, so it is reflexive. It is what triggers the feeling that you have to defecate. However, the external sphincter is under voluntary control. So, if you feel that you have to defecate, you can continue to hold your external sphincter shut, until the urge to defecate diminishes. Then, when it is convenient to do so, the internal sphincter again activates the urge to defecate. The anal sphincter has an internal involuntary part, and an external voluntary part. The internal sphincter has an involuntary reflex which gives your the urge to defecate. If it is not convenient to defecate, then the external sphincter, which is under voluntary control, keeps the anus shut, and after a while, the urge to defecate can subside until a later time when it is convenient to defecate.
the anus
Yes. The anus is actually composed of a few different elements that contribute to the defecation reflex. First, the anal canal is at the lower end of the rectum and is the temporary storage place for feces. When enough feces is in the canal, the pressure triggers the internal anal sphincter (circular muscle) to send a signal to the brain that you need to defecate. If it is not convenient to do so at the time, the external anal sphincter prevents the feces from exiting the anus and suppresses the urge to defecate. This may occur several times until the inevitable happens and the external sphincter has to allow the internal to let go, and voila, another defecation occurs.
The downward projection in the oral cavity that triggers the swallow reflex when it receives contact is the epiglottis. It functions to cover the trachea during swallowing to prevent food or liquid from entering the airway.
The receptor for the salivary reflex is primarily taste receptors located in the taste buds on the tongue. These receptors detect the presence of food in the mouth, which triggers the salivary reflex and leads to the production of saliva.
The autonomic reflex centers are located in the brainstem and spinal cord. The brainstem houses important autonomic centers such as the medulla oblongata and pons, which regulate functions like heart rate and respiration. The spinal cord contains reflex arcs that control activities like urination and defecation.
the anus
The stimulus is what triggers the reflex response.
No, a reflex is a rapid, involuntary response to a stimulus. The stimulus is what triggers the reflex reaction in the body.
stretch receptors
The defecation reflex is initiated by stretching of the wall of the rectum. This reflex facilitates expulsion of feces through the anus.
A reflex test that triggers an involuntary facial twitch
Yes. The anus is actually composed of a few different elements that contribute to the defecation reflex. First, the anal canal is at the lower end of the rectum and is the temporary storage place for feces. When enough feces is in the canal, the pressure triggers the internal anal sphincter (circular muscle) to send a signal to the brain that you need to defecate. If it is not convenient to do so at the time, the external anal sphincter prevents the feces from exiting the anus and suppresses the urge to defecate. This may occur several times until the inevitable happens and the external sphincter has to allow the internal to let go, and voila, another defecation occurs.
The integration centers for the defecation reflex are in the sacral region of the spinal cord and involve the parasympathetic nervous system. The integration centers for the urination reflex are in the spinal cord and brainstem, coordinating signals between the bladder, urethra, and brain to control the process of urination.
The duodenocolic reflex is a gastrocolic reflex that occurs when food enters the duodenum, triggering a reflex response in the colon to promote defecation. This reflex helps facilitate the movement of waste through the digestive system by increasing colonic motility.
The downward projection in the oral cavity that triggers the swallow reflex when it receives contact is the epiglottis. It functions to cover the trachea during swallowing to prevent food or liquid from entering the airway.
The receptor for the salivary reflex is primarily taste receptors located in the taste buds on the tongue. These receptors detect the presence of food in the mouth, which triggers the salivary reflex and leads to the production of saliva.
When you blow on a baby, they may gasp because it triggers a reflex called the "mammalian diving reflex." This reflex helps babies regulate their breathing and heart rate when faced with sudden changes in temperature or pressure.