large intestine - rectum - Physiology Flashcards
(36 cards)
What is the main function of the rectum in the digestive system?
The rectum stores faeces temporarily until they are ready to be eliminated. It signals the brain when it is full through stretch receptors, initiating the process of defecation.
What are stretch receptors in the rectum, and what role do they play in defecation?
Stretch receptors in the rectum detect when the rectum is full. They send signals to the brain to initiate the urge to defecate, helping regulate the timing and control of bowel movements.
What happens when the rectum is full of faeces?
When the rectum is full, stretch receptors in the rectal wall send signals to the brain, signaling the need to defecate. The brain sends signals to relax the internal anal sphincter and allow the faeces to move into the anal canal.
How does the internal anal sphincter contribute to the defecation process?
The internal anal sphincter, made of smooth muscle, relaxes involuntarily when the rectum is full and the brain signals for defecation. This allows the faeces to move from the rectum into the anal canal.
What role does the external anal sphincter play in defecation?
The external anal sphincter, made of skeletal muscle, allows voluntary control over defecation. The sphincter can be contracted to hold faeces in until the individual is ready to defecate.
How does the rectum coordinate the process of defecation?
When the rectum fills with faeces, stretch receptors send signals to the brain.
The internal anal sphincter relaxes involuntarily, while the external anal sphincter allows voluntary control to initiate defecation.
The levator ani muscle helps to push faeces downward, completing the process.
What happens if the external anal sphincter is not voluntarily controlled during defecation?
If the external anal sphincter is not voluntarily relaxed, defecation cannot occur, leading to constipation or the inability to eliminate waste effectively.
What role do smooth muscle and skeletal muscle play in the process of defecation?
Smooth muscle in the internal anal sphincter allows involuntary relaxation during defecation.
Skeletal muscle in the external anal sphincter provides voluntary control to allow or prevent defecation.
How does the rectum contribute to intestinal gas control?
The rectum helps control the passage of intestinal gases by allowing voluntary control through the external anal sphincter, preventing the release of gas unless it is appropriate.
What physiological changes occur in the rectum during defecation?
During defecation, the rectum contracts to move faeces toward the anal canal. The internal anal sphincter relaxes involuntarily, and the external anal sphincter voluntarily relaxes to allow faeces to be expelled.
How does diarrhea affect the function of the rectum?
In diarrhea, the large intestine absorbs less water, leading to liquid stool. The rectum may experience increased urgency to expel faeces quickly and may have less time to store stool before defecation.
What factors influence the rectum’s ability to store stool?
The rectum’s ability to store stool is influenced by:
The tone of the anal sphincters (both internal and external).
The elasticity of the rectal wall, which allows it to stretch without discomfort until it signals the need to defecate.
The nervous system’s control over the timing of defecation.
What does the rectum do in the body?
The rectum stores faeces (poop) until the body is ready to get rid of it. It helps the body know when it’s time to go to the bathroom.
What happens when the rectum fills with faeces?
When the rectum is full, it sends a signal to the brain, telling the body it’s time to go to the bathroom.
What is the role of the internal anal sphincter?
The internal anal sphincter is made of smooth muscle. It relaxes automatically when it’s time to go to the bathroom, allowing faeces to pass into the anal canal.
What is the role of the external anal sphincter?
The external anal sphincter is made of skeletal muscle. It can be controlled voluntarily, meaning you can choose when to relax it and go to the bathroom.
What happens when the rectum gets full?
The rectum sends a message to the brain, saying it’s full. This makes the body want to defecate, which helps the body know when it’s time to go to the bathroom.
How does the body know when to go to the bathroom?
When the rectum is full, stretch receptors in the walls of the rectum send a signal to the brain. The brain then helps you relax the internal anal sphincter and control the external anal sphincter to go to the bathroom.
What is stretch receptors in the rectum?
Stretch receptors are special sensors in the rectum that feel when it’s full. They tell the brain that it’s time to go to the bathroom.
What is the function of the rectum during defecation?
The rectum pushes faeces out into the anal canal and helps the body get rid of waste when you go to the bathroom.
What happens to the internal anal sphincter during defecation?
The internal anal sphincter relaxes automatically when it’s time to go to the bathroom, allowing faeces to pass into the anal canal.
What is the role of the internal anal sphincter?
The internal anal sphincter, made of smooth muscle, relaxes involuntarily when it’s time to defecate, allowing faeces to move into the anal canal.
What is the role of the external anal sphincter?
The external anal sphincter, made of skeletal muscle, allows voluntary control over defecation. It can be consciously relaxed to allow faeces to pass out of the body.
What happens when the rectum is full?
When the rectum is full, stretch receptors in the rectum send a signal to the brain, which triggers the relaxation of the internal anal sphincter and voluntary control of the external anal sphincter for defecation.
