China
Africa
Explore chapters and articles related to this topic
Urinary system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
The intrarenal collecting system is connected to the urinary bladder by the ureters. The ureters are approximately 25–30 cm in length and extend downward from the renal pelvis at the level of the second lumbar vertebra, usually overlying the tips of the transverse processes, to the pelvis. Here they sweep anteriorly around the pelvic sidewall, finally approaching the midline to terminate in the ureteric orifices, 2.5 cm apart in the posterior wall of the bladder. Ureters are completely retroperitoneal structures and composed of a combination of circular and longitudinal muscle. This allows them to transport urine through peristalsis. The inner lining of transitional epithelium prevents fluid and electrolyte absorption. In the ureter there are three natural narrowings: the pelvi-ureteric junction (PUJ), the vesico-ureteric junction (VUJ) and the mid ureter where it crosses the common iliac vessels. Calculi will typically obstruct in one of these three areas.
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2016
David J. Baker, Naima Bradley, Alec Dobney, Virginia Murray, Jill R. Meara, John O’Hagan, Neil P. McColl, Caryn L. Cox
The kidneys are two bean-shaped organs about the size of a fist lying below the rib cage. Though small in size (about 0.5 per cent of the body weight), the kidneys receive approximately 20 per cent of the blood that is pumped out from the heart via the renal arteries. The main parts of the kidney are an outer lightly coloured cortex and an inner darker medulla (Figure 10.7). The renal (kidney) pelvis is the funnel, which collects the urine from nephrons and enables the urine to flow to the ureters. The ureters are the tubes that carry the urine from the kidneys to the urinary bladder.
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
The kidneys – are two bean-shaped organs about the size of a fist lying below the rib cage. Though small in size (about 0.5% of the body weight), the kidneys receive approximately 20% of the blood that is pumped out from the heart via the renal arteries. The main parts of the kidney are an outer lightly coloured cortex and an inner darker medulla (Figure 10.7). The renal (kidney) pelvis is the funnel which collects the urine from nephrons and enables the urine to flow to the ureters. The ureters are the tubes that carry the urine from the kidneys to the urinary bladder.
A two way fully coupled fluid structure simulation of human ureter peristalsis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Ahmed Tasnub Takaddus, Abhilash J. Chandy
The ureter is approximately a 30 cm long tube that connects the kidney to the bladder (Guyton and Hall 2006). Urine is carried through the ureter with isolated boluses moving from kidney to the bladder (van Mastrigt and Tauecchio 1984), known as the peristalsis mechanism. Understanding the peristaltic mechanism is critical, considering the improvement of treatment procedures for anomalies related to ureter peristalsis; say for instance, back-flow of urine from bladder to kidney known as vesicoureteric reflux or, malfunctioning of ureterobesical junction due to congentinal defects (Marieb et al. 2013). Various numerical studies have been performed to understand the urine transport mechanism. Earlier studies only included the fluid domain, and the ureter was modeled as channels or pipes. A lot of these studies modeled ureter peristalsis as a continuous series of sinusoidal waves (Burns and Parkes 1967; Fung and Yih 1968; Yin and Fung 1969; Chow 1970; Shapiro et al. 1969; Jimenez Lozano 2009; Najafi 2015; Najafi et al. 2016). Lykoudis and Roos 1970 was the first to point out that, peristalsis is not a sinusoidal function, and they presented it as an algebraic expression. Griffiths 1987; Griffiths 1989 studied the peristaltic motion and described it as a series of compression waves.
Surface modification of ureteral stents: development history, classification, function, and future developments
Published in Expert Review of Medical Devices, 2023
Kaiguo Xia, Xudong Shen, Xiaojie Ang, Bingbing Hou, Yang Chen, Kaiping Zhang, Zongyao Hao
Urinary tract infection is one of the most common complications of ureteral stents. Some scholars have dissolved antibiotics in relevant degradable biomaterials and added them to the surface of ureteral stents to prevent or reduce the incidence of urinary tract infections. To maintain the concentration of antibiotics in the urine over a period of time and to increase the antibacterial capacity, we need to regulate the degradation process of solutes, many scholars have made different studies about it, as shown in Table 4.
Statistical modelling for cancer mortality
Published in Letters in Biomathematics, 2019
In the world, cancer is one of the deadliest diseases. Our body is made up of different types of cells. Generally, these cells are grown and divided under controlled conditions to create more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and new cells can take place in there. Cancer is the uncontrolled growth of abnormal cells anywhere in a body. These abnormal cells are known as cancer cells, malignant cells or tumour cells. These cells can infiltrate normal body tissues. Cancer refers to cells that grow out of control and invade other tissues. Cells become cancerous due to the accumulation of defects, or mutations, in genetic material (DNA) of a cell. Tobacco use is one of the causes of cancer deaths. Apart from this, another reasons are due to obesity, poor diet, lack of physical activity or excessive drinking of alcohol. Other factors including certain infections, exposure to ionizing radiation and environmental pollutants are also responsible for cancer. Typically, many genetic changes are required for cancer development. Some cancers are due to inherited genetic defects from a people's parents. There are over 200 types of cancer and each is classified by the type of cell that is initially affected. Many cancers and the abnormal cells that compose the cancer tissue are further identified by the name of the tissue that the abnormal cells originated from (e.g. breast cancer, lung cancer and colon cancer). But some cancers do not form tumours (as e.g. Leukemia is a cancer of the bone marrow and blood). Some types of cancer begin in the skin or in tissues that line or cover internal organs (skin, lung, colon, pancreatic, ovarian cancers, etc.). Some of them begin in bone, cartilage, fat, muscle, blood vessels or other connective or supportive tissue (bone, soft tissue cancers). Some cancers begin in the cells of the immune system (i.e. T-cell lymphomas, B-cell lymphomas, etc.) and it can also begin in the tissues of the brain and spinal cord. In human body, the hollow area in the centre of each kidney is renal pelvis. It is a top part of the ureter. The ureter is a kind of long tube which makes a connection between the kidney and bladder. Actually, renal pelvis is very much related with kidney. Transitional cell cancer of the ureter and renal pelvis is a disease in which malignant (cancer) cells form in the ureter and renal pelvis.