Prac 15 Renal System Anta and histo prac PDF

HUB 105 Practical 15: Renal function and urine control of body fluid osmolality Developed by Dr C Willemse edited by Ms M Bennett The primary function of the Urinary System is to help keep the body in homeostasis by controlling the composition and volume of blood. L...

HUB 105 Practical 15: Renal function and urine control of body fluid osmolality Developed by Dr C Willemse edited by Ms M Bennett The primary function of the Urinary System is to help keep the body in homeostasis by controlling the composition and volume of blood. Learning outcomes: The student should be able to: Understanding of renal anatomy and histology Understand control of body fluid osmolarity Explain the effects of hyper- and hypoosmolaric fluids on urination Gross Anatomy: Urinary System The human urinary system consists of two kidneys, two ureters, a urinary bladder and a urethra. Identify these structures as indicated in Figure 1, on the plastic model (torso) and the cadaver (torso or full body) specimen. Figure 1: Frontal view of the human urinary system (Seeley et al, 2003). Kidneys Location: The kidneys are found retroperitoneal in the posterior abdominal region and lie in the extraperitoneal connective tissue immediately lateral to the vertebral column. They extend from the region of vertebra TXII superiorly to vertebra LIII inferiorly. The right kidney is to some extent lower than the left because of its relationship with the liver. The left kidney is longer and more slender than the right kidney and closer to the midline, Figure 2. Page 1 of 9 Figure 2: The retroperitoneal position of the kidneys (Drake et al, 2005). Structure: External features of the kidneys Renal capsule - a layer of fibrous connective tissue that surrounds each kidney Perirenal fat - a dense layer of adipose tissue that attaches the kidneys to the posterior body wall and cushions it against shock Renal fascia - a dense connective tissue layer that anchors the kidneys and the surrounding fat to the abdominal wall Hilum – on the medial margin of each kidney, the renal artery, renal vein, lymphatic vessels, nerves and ureter enter and exit the kidney Internal features of the kidneys Renal cortex – a pale continuous band of tissue that surrounds the renal medulla Renal medulla – consist of the renal columns and the renal pyramids Renal columns - extensions of the renal cortex which project into the aspect of the kidney, and divide the medulla into the renal pyramids Renal pyramids – discontinuous aggregations of triangular shaped tissue; the bases are directed outward towards the renal cortex and the apex of each pyramid projects inward towards the renal sinus Renal papilla – the apical projections of the renal pyramids which are surrounded by the minor calices Page 2 of 9 Minor and major calyx – several minor calices unite to form a major calyx and two or three malor calices unite to form the renal pelvis Renal pelvis – the superior funnel shaped end of the ureter Identify the macroscopic structures as indicated in Figure 3, on the plastic model, the cadaver kidney specimen and the fresh sheep kidney provided in sagittal section. Figure 3: The kidney (Drake et al, 2005). Ureters Location: The renal pelvis narrows as it passes inferiorly through the hilum of the kidney and becomes continuous with the ureter at the ureteropelvic junction. Inferior to this junction the ureters descend retroperitoneally on the medial aspect of the psoas major muscle. At the pelvic brim, the ureter either cross the end of the common iliac artery or the beginning of the external iliac artery, enter the pelvic cavity and continue its journey to the bladder (Figure 4). Structure: The ureters are muscular tubes that transport urine from the kidneys to the bladder. Identify the structures as indicated in Figure 4, on the plastic model (torso) and the cadaver specimen provided. Page 3 of 9 Figure 4: The ureters (Drake et al, 2005). Page 4 of 9 Bladder Location: In its entirety, the bladder is situated in the pelvic cavity when empty, however, it expands superiorly into the abdomen when full (Figure 5). Figure 5: The bladder located within the pelvic area (Drake et al, 2005). Urethra Location: The urethra begins at the base of the bladder and ends with an external opening in the perineum. However, the location differs between females and males (Figures 8 and 9). Figure 9 A: The urethra within the female (Drake et al, 2005). Page 5 of 9 Figure 9 B: The urethra within the male (Drake et al, 2005). Urinalysis The most important function of the kidneys is to assist the body in maintaining homeostasis. This is brought about by regulating pH balance (blood acidity), water balance and electrolyte balance. The kidneys also play an important role in the excretion of waste products. Cautions Do not volunteer to be a subject in this practical if you are suffering from kidney or circulatory problems, have any other medical problem or are on any medications. Urine is a potentially infectious body fluid. Therefore, students are directly responsible for all measurements of the volume, clarity and colour of their own urines, and are required to clean up any spilt urine themselves. When analyzing the unknown samples, please wear gloves. On completion of the experiments, discard of the urine in the toilet and flush. Place the containers in the disinfectant bath after rinsing. Place the test strips and gloves in the hazardous bins provided and wash your hands thoroughly. Page 6 of 9 Approximately 0.6 to 2.5L of urine is produced by renal processes each day. Its composition and physical characteristics may reveal much about the body function. Normal urine is a highly complex aqueous solution. Organic substances Urea formed by liver from ammonia and CO2 Uric acid, an end product of purine oxidation Creatinine, a hydrated form of creatine Inorganic substances Chloride, phosphates, sulphates and ammonia Physical characteristics Colour: Varies from light straw to amber Milky pus, bacteria, fat, etc Reddish-urobillinogen, etc Turbidity: Fresh sample should be transparent May become cloudy after standing a while Odour: Usually odourless Other characteristics: pH ([H+]) o usually 6 (range 4.8 – 7.5) specific gravity o to chart the kidney’s ability to concentrate urine o high specific gravity can indicate a “ wasting” process, for example cancer o severe renal damage may reflect a reading at a low 1.010 Abnormal constituents Glucose Warning sign of diabetes mellitus (sweet urine) Ketones Intermediary products of fat and protein metabolism. Ketonuria occurs in diabetes mellitus and during periods of stress Blood May be as a result of high altitudes, kidney stones, etc Hemoglobin Hemoglobinuria may indicate hemolytic anemia, transfusion reactions, smallpox, malaria, hepatitis, renal infections etc. Bilirubin Breakdown product of bile. May indicate blocked bile ducts, cirrhoses of the liver or liver cancer Page 7 of 9  Protein High molecular weight molecule usually not excreted into the kidney. May indicate impairment of kidney functioning. Task 1: Healthy volunteers previously selected will fill-in and hand-in consent forms before participating in the experiment on the day. Subjects would have followed these instructions: o Light breakfast at least 2hours before practical, no coffee/tea consumed, only 1 glass water (250ml) until experiment. Before consumption of the liquids, control urine of subjects has to be measure: colour, clarity and dipstick test for specific gravity and pH. Group A’s volunteers will consume 800ml of filtered water per subject Group B’s volunteer will consume 800ml of an isosmotic solution (1 ½ tsp table salt in water) Group C’s volunteer will consume a standard cup of black coffee, no sugar. Determine the urine o Volume for both groups (collect within 30min in a measuring beaker and then at 30min intervals for 90mins - do not discard urine until completion of collection) o Using dipsticks determine; pH, specific gravity, clarity and colour o Construct a table of the results and discuss. ALWAYS RELY UPON YOUR DOCTOR OR HEALTH CARE PROFESSIONAL TO DETECT, DIAGNOSE AND TREAT ANY INFECTION OR ABNORMALITY Materials Urine (subjects own) 500ml/1000ml measuring beaker Urinalysis dipsticks and chart Toweling paper Alcohol swabs Method - Subjects will collect and measure urine voided in the bathroom. - Place dipstick in the urine, make sure to hold the dipstick horizontal to avoid contaminating the pigmented pads, discard the urine in toilet and return with dipstick and remember urine volume. - Plot a table of the values measure over time. - The steps above should be repeated every 30mins for the 90mins of the experiment. Page 8 of 9 Task 2: Gross Anatomy Section: Identify all renal structures and their locations on the wet specimens, diagrams and models provided. Task 3: Histology: View the following slides at 4x and 10x magnification 1. Kidney (H&E L/S or C/S) - Identify: cortex, medulla (note the striated appearance, what’s the reason for this ?), glomeruli 2. Bladder (H&E) - Identify: Mucosa layer with transitional epithelium and lamina propria 3. Ureter (H&E) - Identify: luman, inner mucosa layer (comprising of?), muscular layer (note longitudinal and circular muscle bands) References 1. Drake R. L., Vogl W. and Mitchell A.W.M. (2005). Gray’s Anatomy for students. Churchill Livingstone. 2. Seely R., Stephens T.D., and Tate P. (2006). Anatomy and Physiology. McGraw-Hill Higher Education. 7th edition. 3. http://www.histology.leeds.ac.uk/urinary/kidney.php 4. http://www.lab.anhb.uwa.edu.au/mb140/corepages/urinary/urinary.htm Page 9 of 9