1 Regulation of water content

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1 Class: Name: ( ) Date: E1 1 Regulation of water content 1.1 Importance of osmoregulation (Book E1, p. 3) If there is an imbalance between water intake and water loss, the (1) content of the blood and hence the (2) of the tissue that surrounds body cells will change. Water will therefore enter or leave the cells by (3). If too much water is gained or lost, the cells will not function properly and may even die. The maintenance of a stable water potential of body in an organism is known as (4) ( 滲透調節 ). The (5) ( 腎 ) of the (6) ( 泌尿系統 ) play an important part in this regulatory function. 1.2 The general plan of the urinary system (Book E1, p. 5) (dorsal aorta) (posterior vena cava) (renal artery ( 腎動脈 )) (renal vein ( 腎靜脈 )) (1) (2) ( 輸尿管 ) (3) female Key: / blood flow ( 膀胱 ) two rings of (4) ( 括約肌 ) (5) ( 尿道 ) (penis) male The human urinary system (structures in brackets do not belong to the urinary system) (Second Edition) - E1-1 -

Structure Kidney Feature and / or function Surrounded by fat which protects the kidneys from (6) Supplied with blood from the (7) and drained by the (8) Responsible for osmoregulation and (9) Ureter

of urine from the urinary bladder to the urethra Urethra Carries urine from the urinary bladder to the outside Go to Practical 1.1 Examination of the mammalian urinary system (Book E1, p. 113) 1.

2 Structure Kidney Feature and / or function Surrounded by fat which protects the kidneys from (6) Supplied with blood from the (7) and drained by the (8) Responsible for osmoregulation and (9) Ureter Carries (10) produced by the kidneys to the urinary bladder (11) urine temporarily Urinary bladder Two rings of sphincter muscles (normally (12) (contracted / relaxed) are present to control the (13) of urine from the urinary bladder to the urethra Urethra Carries urine from the urinary bladder to the outside Go to Practical 1.1 Examination of the mammalian urinary system (Book E1, p. 113) 1.3 Structure of the kidney (Book E1, p. 7) (1) ( 腎元 ) are the functional units of the kidney. (5) renal artery renal vein ureter Position of nephrons in the kidney (2) ( 皮層 ) (3) ( 髓 ) (4) ( 腎盂 ) branch from renal artery branch from renal vein (Second Edition) - E1-2 -

A nephron is made up of a (6) ( 腎小球 ), a (7) ( 鮑曼氏囊 ) and a long tubule. The tubule can be divided into several sections.

3 It returns to the cortex and coils up again to form the (10) ( 遠曲小管 ). The distal convoluted tubule finally leads to the (11) ( 集尿管 ).

efferent arteriole ( 輸出小動脈 ) afferent arteriole ( 輸入小動脈 ) branch from renal artery branch from renal vein I II III IV V capillary VI cortex medulla (from

3 A nephron is made up of a (6) ( 腎小球 ), a (7) ( 鮑曼氏囊 ) and a long tubule. The tubule can be divided into several sections. 1 First the tubule coils up in the cortex to form the (8) ( 近曲小管 ). 2 It then extends into the medulla to form the U-shaped (9) ( 亨利氏套 ). 3 It returns to the cortex and coils up again to form the (10) ( 遠曲小管 ). The distal convoluted tubule finally leads to the (11) ( 集尿管 ). Match parts I to VI of a nephron with their names. efferent arteriole ( 輸出小動脈 ) afferent arteriole ( 輸入小動脈 ) branch from renal artery branch from renal vein I II III IV V capillary VI cortex medulla (from another nephron) Key: blood flow flow of urine A nephron and its associated blood vessels glomerulus: (12) Bowman s capsule: (13) proximal convoluted tubule: (14) loop of Henle: (15) distal convoluted tubule: (16) collecting duct: (17) Go to Practical 1.2 Examination of the mammalian kidney (Book E1, p. 116) (Second Edition) - E1-3 -

The high blood pressure forces (4) and small (5) (soluble / insoluble) molecules (e.g. glucose, amino acids, salts and urea) in the plasma through the thin walls of the (6) and the (7) into the capsular space.

4 1.4 Formation of urine (Book E1, p. 10) (1) ( 超濾 ) and (2) ( 重吸收 ) are two main processes involved in urine formation. 1 Ultrafiltration When the blood reaches the glomerulus, it is maintained at a relatively (3) (high / low) pressure. The high blood pressure forces (4) and small (5) (soluble / insoluble) molecules (e.g. glucose, amino acids, salts and urea) in the plasma through the thin walls of the (6) and the (7) into the capsular space. This process is called ultrafiltration. It is a (8) (active / passive) process. (10) arteriole blood flow (9) arteriole urea Bowman s capsule glomerulus salts capsular space (with (11) ( 腎小球濾液 )) glucose amino acids water to proximal convoluted tubule Ultrafiltration in the glomerulus and the Bowman s capsule The glomerular filtrate has a similar composition to (12). However, no (13) and (14) are found in the glomerular filtrate because they are too (15) to pass through the walls of the glomerulus and the Bowman s capsule. (Second Edition) - E1-4 -

5 2 Reabsorption After ultrafiltration, the glomerular filtrate flows through the kidney tubule. Meanwhile, (16) substances (e.g. glucose and amino acids) and most of the (17) in the filtrate are absorbed back into the surrounding capillaries. This process is called reabsorption. Reabsorption occurs mainly in the (18). Adaptive features of the proximal convoluted tubule for reabsorption: Feature It is long and highly (19). It is only one-cell thick. The epithelial cells have many (22). The epithelial cells contain many (24). Surrounded by a dense (27) network Adaptation to reabsorption Increases the (20) and the time for reabsorption Shortens the (21) for reabsorption Greatly increases the (23) for reabsorption Provides cells with a lot of (25) to enable (26) of substances The blood allows the rapid transport of substances away from the site of reabsorption, thus helping maintain a steep (28) of substances between the blood and the filtrate for efficient reabsorption Key: blood flow flow of urine glomerulus proximal convoluted tubule distal convoluted tubule to renal vein glucose, amino acids and salt from renal artery Bowman s capsule capillary loop of Henle collecting duct water urea glomerular filtrate epithelial cells capillary of proximal convoluted tubule Process(es) by which substances are reabsorbed (d = diffusion; o = osmosis; a = active transport): (29) (30) (31) (Second Edition) - E1-5 -

6 The reabsorption of specific substances in different parts of the kidney tubule: Substance absorbed (% reabsorbed) (32) (100%) (33) (100%) (34) (80%) Process Diffusion, active transport Diffusion, active transport Diffusion, active transport Part of the kidney tubule where reabsorption occurs Proximal convoluted tubule Loop of Henle Distal convoluted tubule Collecting duct (35) (99%) (36) (50%) Osmosis Diffusion After reabsorption, the remaining filtrate in the collecting duct is called (37), which contains mostly water with salts, (38) and other metabolic waste. 1.5 The role of kidneys (Book E1, p. 17) A Osmoregulation (Book E1, p. 17) A stable water potential of body is mainly achieved by regulating the amount of (1) reabsorbed from the glomerular filtrate in the kidney tubules. The amount of water reabsorbed in the kidney tubules is controlled by the (2) (ADH) ( 抗利尿激素 ) released from the (3) ( 垂體 ). ADH increases the (4) of the collecting duct to water so that a (5) (greater / smaller) proportion of water is reabsorbed from the filtrate. As a result, the volume of urine production is (6) (increased / decreased) and more water is retained in the body. The release of ADH is controlled by the (7) ( 下丘腦 ) in the brain. The hypothalamus contains (8) which can detect the water potential of the blood. (Second Edition) - E1-6 -

7 How osmoregulation is carried out when the water potential of the blood becomes higher or lower than normal: water potential of blood higher than normal (e.g. after drinking a large amount of water) water potential of blood lower than normal (e.g. taking in little water or heavy sweating) detected by osmoreceptors in hypothalamus detected by osmoreceptors in hypothalamus the pituitary gland releases (9) (less / more) ADH the pituitary gland releases (14) (less / more) ADH wall of collecting duct becomes (10) (less / more) permeable to water wall of collecting duct becomes (15) (less / more) permeable to water a (11) (greater / smaller) proportion of water reabsorbed; a (12) (larger / smaller) volume of (13) (dilute / concentrated) urine formed a (16) (greater / smaller) proportion of water reabsorbed; a (17) (larger / smaller) volume of (18) (dilute / concentrated) urine formed negative feedback normal water potential of blood negative feedback B Excretion (Book E1, p. 19) Excretion is the elimination of (19) from the body. Metabolic waste (e.g. urea) is constantly produced and a high concentration of it is toxic to the body. The kidneys remove metabolic waste from the blood by forming urine. 1.6 The dialysis machine (Book E1, p. 21) Patients with (1) ( 腎衰竭 ) cannot regulate the water content of the body or remove metabolic waste from the blood effectively. They can be treated with (2) ( 血液透析 ) by using a (3) ( 透析機 ) (or a kidney machine ( 洗腎機 )). (Second Edition) - E1-7 -

Features of the two parts of a dialysis machine and their significance: Dialysis tubing Dialysing ( 透析液 ) Feature It is (4) permeable. It only allows small molecules like urea to pass through.

Significance Helps remove (5) from the blood while retaining large blood components like plasma proteins and blood cells in the body Prevents loss of (6) from the blood Prevents loss of (7) from the

8 Features of the two parts of a dialysis machine and their significance: Dialysis tubing Dialysing ( 透析液 ) Feature It is (4) permeable. It only allows small molecules like urea to pass through. Has a water potential similar to that of blood. The concentrations of nutrients (e.g. glucose and amino acids) in it are similar to that of blood. (8) (Contains / Does not contain) metabolic waste. Significance Helps remove (5) from the blood while retaining large blood components like plasma proteins and blood cells in the body Prevents loss of (6) from the blood Prevents loss of (7) from the blood Allows metabolic waste in the blood to diffuse into the Key: blood flow flow of 1 Blood is pumped out of the patient s body. pump 3 Nutrients are retained in the blood (no net movement of nutrients) as their concentrations in are similar to those in blood. blood dialysis tubing 5 Cleaned blood returns to the patient s body. fresh dialysis tubing constant temp. bath 2 Metabolic waste like urea diffuses from the blood to the along the concentration gradient. used 4 Plasma proteins and blood cells are retained in the blood as they are too large to pass through the tubing. How a dialysis machine works (Second Edition) - E1-8 -

9 Answers E1 Ch 1 Regulation of water content water 2 water potential 3 osmosis 4 osmoregulation 5 kidneys 6 urinary system kidneys 2 ureters 3 urinary bladder 4 sphincter muscles 5 urethra 6 mechanical shock 7 renal arteries 8 renal veins 9 excretion 10 urine 11 Stores 12 contracted 13 release Nephrons 2 cortex 3 medulla 4 pelvis 5 nephron 6 glomerulus 7 Bowman s capsule 8 proximal convoluted tubule 9 loop of Henle 10 distal convoluted tubule 11 collecting duct 12 I 13 II 14 IV 15 III 16 V 17 VI Ultrafiltration 2 reabsorption 3 high 4 water 5 soluble 6 glomerulus 7 Bowman s capsule 8 passive 9 afferent 10 efferent 11 glomerular filtrate 12 plasma 13 plasma proteins / blood cells 14 blood cells / plasma proteins 15 large 16 useful 17 water 18 proximal convoluted tubule 19 coiled 20 surface area 21 distance 22 microvilli 23 surface area 24 mitochondria 25 energy 26 active transport 27 capillary 28 concentration gradient 29 d & a 30 o 31 d 32 Glucose / Amino acid 33 Amino acid / Glucose 34 Salt 35 Water 36 Urea 37 urine 38 urea water 2 antidiuretic hormone 3 pituitary gland 4 permeability 5 greater 6 decreased 7 hypothalamus 8 osmoreceptors 9 less 10 less 11 smaller 12 larger 13 dilute 14 more 15 more 16 greater 17 smaller 18 concentrated 19 metabolic waste kidney failure 2 haemodialysis 3 dialysis machine 4 differentially 5 urea 6 water 7 nutrients 8 Does not contain (Second Edition) - E1-9 -

Sunday, July 17, 2011 URINARY SYSTEM

Sunday, July 17, 2011 URINARY SYSTEM URINARY SYSTEM URINARY SYSTEM Let s take a look at the anatomy first! KIDNEYS: are complex reprocessing centers where blood is filtered through and waste products are removed. Wastes and extra water become