Micturition

Micturition (peeing) starts with urine flowing from the kidneys to the bladder via ureters. The bladder expands using transitional epithelium. Urine exits through the urethra, controlled by internal and external urethral sphincters. Ureters prevent backflow, thereby reducing infection risk. Created by Raja Narayan. Caffeine is a diuretic that, through a signaling cascade and participation in RAAS through increasing levels of free adenosine by blocking the adenosine receptor (same reason it wake you up), leads to increased water excretion and salt excretion. Not sure if the videos on this website discuss RAAS but if you are interested in renal physiology you need to cover it. Cranberries help prevent the typical bacteria, E.coli, from attaching to the bladder wall with their fimbriae and starting an infection. However, cranberry pills are concentrated and may be more effective then drinking juice, although they are a food supplement and do not have to conform to any requirements by the food and drug administration. Other suggestions may also be helpful such as frequent urination to flush out the urethra and prevent e. coli from getting in to the bladder. Voiceover: Next time you're with a group of friends, and you have to go pee, be a little fancy. Stand up and announce to them that I must now undergo micturition. Micturition, which is a fancy phrase for "to pee," or "to urinate." And so in this video we're gonna talk about the process of micturition. Beginning where we lef...

Micturition Micturition or urination is the process of expelling urine from the bladder. This act is also known as voiding of the bladder. The Browse more Topics under Excretory Products • Introduction to Excretory System • Human Excretory System • Urine Formation • Regulation of Excretion • Role of the Other Organs in Excretion • Disorders of the Excretory System Stages of Micturition The urinary bladder has two distinct stages or phases: • Resting or filling stage • Voiding stage Resting or Filling Stage It is in this phase of the bladder that the urine is transported from the kidneys via the ureters into the bladder. The ureters are thin muscular tubes that arise from each of the kidneys and extend downwards where they enter the bladder obliquely. The oblique placement of the ureters in the bladder wall serves a very important Voiding Stage During this stage, both the urinary bladder and the urethra come into play together. The detrusor muscle of the urinary bladder which was relaxing so far starts to contract once the bladder’s storage capacity is reached. The urethra is controlled by two sets of muscles: The internal and external urethral sphincters. The internal sphincter is a smooth muscle whereas the external one is Physiology of Micturition (Image Source: austincommunitycollege.com) Learn more about As mentioned earlier, the process of The micturition reflex is ultimately generated from the level of the spinal cord after it receives reflexes from the pontine regio...

\( \newcommand\) • • • • • Micturition is the ejection of urine from the urinary bladder through the urethra to the outside of the body. Key Points • In infants, elderly individuals, and those with neurological injury, urination may occur as an involuntary reflex. • Physiologically, micturition involves coordination among the central, autonomic, and somatic nervous systems that stem from different centers of the brain. • The brain centers that regulate urination include the pontine micturition center, periaqueductal gray, and the cerebral cortex. • Micturition consists of a storage phase and a voiding phase. Stretch receptors in the bladder increase their firing rate as the bladder becomes more full. This causes the micturition reflex, and increases urinary urge, and can even cause involuntary urination. Key Terms • micturition: Also known as urination, this is the ejection of urine from the urinary bladder through the urethra to the outside of the body. • urine: A liquid excrement consisting of water, salts, and urea that is made in the kidneys then released through the urethra. Micturition, also known as urination, is the ejection of urine from the urinary bladder through the urethra to the outside of the body. In healthy humans the process of urination is under voluntary control. In infants, elderly individuals, and those with neurological injury, urination may occur as an involuntary reflex. Physiology of Micturition Physiologically, micturition involves the coordinati...

The Urinary Process. Urination is a complex process controlled by muscles of the bladder and sphincter mechanism and by modulatory centers in the central and peripheral nervous systems. The detrusor muscle is a complex meshwork of interlaced smooth muscle bundles that contract in a way that squeezes urine from the bladder vesicle. The sphincter mechanism consists of smooth muscle in the bladder neck and proximal urethra, a striated muscle sphincter consisting of slow twitch muscle fibers in the urethral wall, and periurethral muscles that are a component of the pelvic floor muscles. The detrusor relaxes during bladder filling to accommodate increasing volumes at a low pressure, and the sphincter remains tightly closed. During urination, the detrusor contracts and the sphincter mechanism relaxes, allowing smooth outflow of urine. As the bladder fills, modulatory centers in the brain prevent the occurrence of contractions. Meanwhile, the sphincter mechanism remains closed under autonomic and somatic nervous system control. During urination, the inhibition of contractions is removed and a reflex originates in the pontine micturition center. That causes the detrusor muscle to contract and the sphincter mechanism to relax. The location of the final output of central nervous system impulses to and from the bladder and sphincter is the sacral micturition center, located in spinal segments 2, 3, and 4, which must be intact for contraction to occur. Injury to the pontine micturitio...

• 1 Shape of the Bladder • 1.1 Musculature • 2 Vasculature • 3 Lymphatics • 4 Nervous Supply • 4.1 The Bladder Stretch Reflex • 5 Clinical Relevance: Spinal Cord Injuries and the Bladder • 6 Clinical Relevance: Urine Retention The bladder is an organ of the urinary system. It plays two main roles: • Temporary storage of urine – the bladder is a hollow organ with distensible walls. It has a folded internal lining (known as rugae), which allows it to accommodate up to 400-600ml of urine in healthy adults. • Assists in the expulsion of urine – the musculature of the bladder contracts during micturition, with concomitant relaxation of the sphincters. In this article, we shall look at the anatomy of the bladder – its shape, vasculature and neurological control. Shape of the Bladder The appearance of the bladder varies depending on the amount of urine stored. When full, it exhibits an oval shape, and when empty it is flattened by the overlying bowel. The external features of the bladder are: • Apex – located superiorly, pointing towards the pubic symphysis. It is connected to the umbilicus by the median umbilical ligament (a remnant of the urachus). • Body – main part of the bladder, located between the apex and the fundus • Fundus (or base) – located posteriorly. It is triangular-shaped, with the tip of the triangle pointing backwards. • Neck – formed by the convergence of the fundus and the two inferolateral surfaces. It is continuous with the urethra. Urine enters the bladder...

Frequent urination is the need to pee more often than average (seven to eight times) throughout the day. It can happen to anyone, but it’s more common in people over the age of 70, pregnant people and people with an enlarged prostate. The most common cause is urinary tract infections. Treatment depends on the underlying cause. Overview UTIs and other conditions that affect your urinary tract are the most common causes of frequent urination, but there can also be other causes. What is frequent urination? Frequent urination is when you need to pee too many times throughout the day or night. It’s inconvenient and disruptive to your daily life. It’s a common complaint among all people, regardless of sex or gender. Frequent urination is a symptom of many different conditions and can have a wide variety of treatments. It can be a symptom of pregnancy or a In many cases, your healthcare provider can help relieve frequent peeing by treating the underlying condition. Frequent urination at night It’s common to occasionally wake up at night to pee. In fact, it’s normal to get up to urinate. In general, you can expect to pee once a night in your 40s and 50s, twice a night in your 60s and 70s and even two to three times a night in your 80s and beyond. But waking up too often in the night can keep you from getting enough sleep and is sometimes a sign of a health condition. This type of frequent urination is called What’s normal and how many times is too frequent to urinate? Most people ...

A number of conditions can cause painful urination (dysuria). In women, urinary tract infections are a common cause of painful urination. In men, urethritis and certain prostate conditions are frequent causes of painful urination. Medical conditions and external factors that can cause painful urination include: • • • • Drugs, such as those used in cancer treatment, that have bladder irritation as a side effect • • • Having a recent urinary tract procedure performed, including use of urologic instruments for testing or treatment • • • • • Soaps, perfumes and other personal care products • • Urethritis (infection of the urethra) • • • • Rakel RE, et al., eds. Urinary tract disorders. In: Textbook of Family Medicine. 9th ed. Philadelphia, Pa.: Elsevier Saunders; 2016. https://www.clinicalkey.com. Accessed Aug. 3, 2017. • Henderson MC, et al. Dysuria. In: The Patient History: An Evidence-Based Approach to Differential Diagnosis. 2nd ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://accessmedicine.mhmedical.com. Accessed Aug. 3, 2017. • Hooton TM, et al. Acute uncomplicated cystitis and pyelonephritis in women. https://www.uptodate.com/contents/search. Accessed Aug. 3, 2017. • Swygard H, et al. Approach to infectious causes of dysuria in the adult man. https://www.uptodate.com/contents/search. Accessed Aug. 3, 2017.