Module 5.2 Flashcards
what is excretion
the removal of metabolic waste from the body
what is metabolic waste
a substance that is produced in excess metabolic processes in the cells , it may become toixc .
what products must be excreted
almost al products that are formed in excess by the chemical processes occuring in the cell must be removed from the body , so that they do not build up and inhibit enzyme activity or become toxic .
main excretory products are
-carbon dioxde from respiration
- nitorgen contaianig n compounds such as urea
other compounds such as the bile pigments found in feaces .
do no confuse EXCRETION WITH POOOPPYYY
Egestion is the elimination of the feaces from the body . Faces are the undigested remsains of food that are not metabolic products
excretory organ LUNGSS -what is it wxtection
carbondioxide - apssed from the cells of respiring tissues int o the bloodstream where i is transported mostly int he form of hydrogen carbonate iions to the lungs , int he lungs the carbondioxide diffuses into the alveloi to be excreted as you breathe out .
excretory organs - the liver
the liver is directly involved in excretion , it has manay metabolic roles , and some of the substances produces will be passed into the bile for excretion , with the faces , for example the pigment bilirubin .
excretory organs - the liver - what else is it involved in
the liver is also invovled in converting excess aminoa cids to urea . Aminoa cids are broken down by the proces of deamiantion . The ntiorgen contaianig aprt of the moelcule is then combined iwth carbondioxide to make urea .
exvretory organ - kidneys - what does it excrete
the urea is passed into the bloodstream to be transported to the kdineys . Urea is transproted in solution - dissolved injt he plasma . In the kidneys , the urea is removed fromt he blood to become part of the urine . Urine is stored in the bladder before being excreted fromt he bod via the urethra .
excretory organa - rhe skin - wht does it excrete
the skin s also involved in excrtetion but excretion is not the primar function of the skin . Sweat contains a range of substances including salts ure , water uric aicfd nd mmonia . Urea , uric acid and mmonia are all excreotry products . The loss of water nd salts my be important part of hoemostiss 0 mainti body temp and water potential of the blood .
what is the importance of excretion
allowing the products of metabolism to build up could be fatal as some metabolic rpoducts ilek co2 is toixc t hey inerfre with cell rpcoresses by altering hte ph that normal metbaolism is rvented and other metabolic porducts may ct as inhibtors and reduce the actiivt of essential enzmes .
how is most carbondioxide transported in the blood as
hdyrogen carbonte tions .
but also form hdyorgen ions check page .
-this occurs inside the red blood cells under the infleunce of the enzzyme cabronic anhydrase bt can also occur in the blood plasma .
how can hdyorgen ions affect the pH of the cytoplasm in the red blood cells .
the hdyorgen ions interact with bonds within haemoglobin , changing its three dimensional shape . THIS reducs the affinit of haemoglobin for oxygen affecting oxygen transport .
how can hdyorgen ions affect the pH of the cytoplasm in the red blood cells . (2)
the hdorgen ions can then combine with haemoglobin forming the hemoglbonic acid . The carbondioxide that is not converted to hdyrogen carbonate ions can combine direclty with hemoglobn , producing carboaminohaemoglobin . Bothhaemoglobinic acid and carbaminohaemoglobin are unable to combine with oxygenn as normal reducing oxygen tranasport further .
why is maintainig the ph of the blood plasma essential
becuse changes could alter the structure of the many proteins int he blood that helps to transprot a wide range of substances aroudn the bod . Porteins int he blood act as buffers to resit the change in PH .
What hapens if the change in pH is small
then the extra hdyorgen ions are dected by the respriatory center int he medulal obongata of the brain , causing an increase in breahing rate to help to remove the excess carbondixoide .
hat hapens if the blood pH droops below 7.35
it cuses headaches , dorwsiness , restlessness ,t reor and foncusion . There may also e rapid heart rate and changes in blood pressure , this is RESPIRATORY ACIDOSIS , it can be caused b disease or codnitons tha affect the liungs themsleevs ,s ucha s emphsyemea , chronic bronchitis astha or severe onemonia , nbocage o the airway due o swelling of a forein objec tor vomit cn also idnce acute resiprotary acidosis
can the body store nitrogenous compoudns (1)
the body cannot store excess amino acids . However , amino acids contain almost as much enegy as carbodhyrates . Therefore it ould be wasreful simply toe xcrete excess aminoa cids , instead they are transported to the liver nd the potenitally oxic amina cids groups ir remoced (deamiantion )
can the body store nitrogenous compoudns (1)
check page 25 for equation for deaminaiton and
deamanation for urea
and firmation of urea
The amino gorp intially forms the very soluble and highly toxic compound , mmonai . This is converetd to a less soluble and less toxic compoud called urea , which can be rnspored to the kidneys for be converted to carbohdyrate or fat for storage .
Why does the liver need a good blood supply
The liver cekks carry out many hundreds of metabolic processes so the liver has an important role in homeostasis . It is therefore essential thst thr liver has s good supply of blood
What does thr internal structure of the liver ensure for good blood supply
It ensures that as much blood as possible flows past as many liver cells as possible . This enables the liver cells to remove excess or unwanted substances from thr blood snd return substances to the blood to ensure concentrati9ns are maintained .
How does the HEPATIC ARTERY supply thr liver with blood
The hepatic artery oxygenated blood from the heart travels from thr aorta via the hepatic artery into the liver . This supplies the oxygen that is essential for aerobic respiration .
Why are the liver cells very active
The liver cells are very active because they carry out many metabolic processes . Many of these processes require energy in thr form of ATP so it in important that the liver is a good supply of oxygen for aerobic respiration .
Another blood supply to the liver is the HEPATIC PORTAL VEIN
The hepatic portal vein , deoxygenated blood from the digestive system enters the liver via the hepatic portal vein . This blood is rich in the products of digestion . The concentrations of various substances will be uncontrolled as they have just entered the body from the products of digestion in the intestines .
The hepatic portal vein (2)
The blood may also contain toxic toxic compounds that have been absorbed from the intestine . It is impritwjtnthat such substances do not continue to circulate around the body before their concentrations have been adjusted .
How does blood leave the liver
Via the hepatic vein . The hepatic vein rejoins the vena cava and blood returns to the body’s normal circulation .
A fourth vessel is connected to the liver what does it do
I
This is the bile duct . Bile is a secretion from the liver which has vessels it is the bile duct. Bile is a secretion from thr liver which has functions in digestion and excretion . The bile duct carries a bile from the liver to the gall bladder , where it is stored until required to aid the digestion of fate in the small intensities .
Bile also contains excretory products
Bile also contains some excretory products such as bile pigments like bilirubin which will leave the body with the faeces .
How is the structure of the liver arranged
The cells blood vessels and chambers inside thr liver cekks . The liver is divided into lobes which are further divided into lounukes which are YLINDRIFWL .
How blood passes through the liver
As the hepatic artery and hepatic portal vein enter the liver , they split into smaller and smaller vessels . Are known as inter lobular vessels .
How blood is transported in the liver (2)
At intervals , branches from the hepatic artery and the hepatic portal vein enter vein enter thr lobules . These vessels run blood from thr two blood vessels is ,iced and passes along special chamber called ansinusoid , which is lined with liver cells . As the blood flows along the sinusoid it is in close contact with the liver cells . These cekks are able to to remove substances from thr b,kf snd return other exuberance’s to thr blood .
What are kupifer cells
Specialised macrophages called kupifer cells move about within the sinusoid . Their prow,Roy functions appears to be to breakdown and recycle old red blood cells . One of the products of hameoglobin breakdown is bilirubin , which is one of the bile pigments excreted as part of the bile .
How is bile made snd produced
Bile is made in thr liver cells and is released into the bile csnaliculi the bile is canaculi join together to form thr bile duct m which transports bile into the gall bladder .
What Happens when blood reaches the end of the sinusoid
The concentrations of many of its components have been modified snd regulated . At the Center of each lobule is a branch of the hepatic vein known intralobular vessel . The sinusoid , empty into this vessels . The branched of the hepatic vein from different lobules join together to form the he
Attic vein which drains blood from the liver .
Check figure 4 page 27
Arrangements of cells in a lobules
Describe the structure liver cells
Liver cells or hepatocytes appear to be relatively unspecialised . They have a simple cuboidal shape with many microfilm kn their surface . However , their many metabolic functions include protein synthesis .
Describe the liver cells (2)
However , their metabolic functions include,UFE protein synthesis transformation and storage of carbohydrates synthesis of cholesterol and bile salts detoxifications and many other processes . This. Dan’s thst their cytoplasms must be very dense snd is specialised in the number of certain organelles it contains .
What is an ornithine cycle
A series of biochemical reactions thst converted ammonia to urea .
Many metabolic functions of liver (1)
-controls of blood glucose levels amino acid levels lipid levels .
- synthase or bile plasma proteins and cholesterol
- synthesis kf red blood cells in the foetus .
Many metabolic functions (2)
Storage of vitamins A and D and B12 iron glycogen .
Detoxification of alcohol drugs
Breakdown of hormones
Destruction of red blood cells .
In depth about the liver storing glyocen
Liver stores sugar in the form of glycogen . It is we,e to store approximately 10l-120 of glycogen , which makes Jo to 8 perfect kf of thr fresh drjght of thr liver ,
Storage of glycogen
How does glycogen form granules , in the cytoplasms kf the hepwtocytes . This glycogen can be broken down to re,essentially glucose into the blood as required . The control of blood glucose concentrations is described .
What does the liver detoxify
One important role of thr liver is to detoxify substances thst may cause harm . Some of these compounds such as hydrogen peroxide are produced in thr body . Others such as alcohol may be consumed as part of our diet may be taken for health and recreational response , for example medicines .
How can toxins be rendered
Toxins can be rendered by harm,Ed’s by oxidation reduction methylation or by combination which another molecule . Liver cells contain an Andy,es thst render toxic molecules led toxic ,
Detoxifying liver enzyme one
Catalase , which concerts hydrogen peroxide , to oxygen snd water . Catalase , has a particularly high turnover number (the number of molecules of hydrogen peroxide thst one molecule of catalase can rodent harm,ess in one seconds ).
Detoxyfing liver enzyme two
Cytochrome p40 which is a group of enzymes used to breakdown drugs including cocaine snd various medicinal drugs . The cytochrome are also hsed in other metabolic reactions such as electron transport during reeilriarion .
Their role in metabolic,sims dehgs can interfere with other metabolic roles as cause the unearned side effects in some other medicinal drugs Breakdown of.
Interesting fact obt alcohol
Alcohol or ethanol is a drug that depresses nerve acidity in addition to, alcohol contains chemical potential energy potential. Energy which can be used for respiration .
How is alcohol broken down in thr liver (1)
Alcohol is broken down by in the hepatocytes by the action of the enzyme ethanol dehydrogenase . The resulting compounds is ethanol . This is dehydrogenase’s further by the enzymes Ethan’s, dehydrogenase .
How is alcohol broken down in the liver (2)
The final compound produced is ethanoate acetate . This acetate is combined with coenzyme A to form acetylene coenzyme A, whuch enters the process of aerobic respiration . The hydrogen atoms released from alocihol are combined with another conesyme called NAD , to form reduced NAD . ADEROXIFICSTION OF ALCOHOL FIGURE 1
NAD is required for what in thr liver
It is required to oxidise and breakdown fatty acids for use in respiration .
What if the liver has detoxify too ,cut alcohol
It uses up its store of NAD and has in sufficient left to deal with thr fatty acids for. These fatty acids are then converted back to lipids snd stored as fat in the hepatocytes causing thr liver to become enlarged this condition is known as fatty liver which can lead to slcjol related hepatitis or to cirrhosis .
Formation of urea (1)what can happen to e Cessna amino acids
Excess amino acids cannot be stored because the amino grill makes them toxic ..nhiwever , thr amino acid molecules contain a lot of energy so it
Formation of ureas 2
would be wasteful to excrete the whole molecule . Therefore , excess amino acids undergo treatment in the liver to remove and excrete the amino component . This treatment consist kf two process deamjnjantikn by the krnjthjne cycle,e .
Figure2 of 29
…
How does deamination
The process of deamination remove the amino group and produces ammonia. Ammonia is very soluble and highly toxic and therefore ammoniamustnkt be allonwed to accumulate .
DESMINATIIN also produces an organic compound a kerosene acids which can enter respiration directly to release its energy.
As ammonia is soluble and toxic it must be converted to a less toxic for very quickly . Ornithine
The ammonia is combined with carbon dioxide to produce urea , . This occurs in thr ornithine cycle . Ammonia and carbon dioxide combine with the amino acids ekrnithi etoproduce citrus line. This is converted to arginine by addition of further ammonia . The arginine is the recovered to ornithine by the removal urea .
How is urea passed into the bloodline
Urea is both less soluble and less toxic than ammonia . It can be passed back into the blood , and transported around the body to the kidneys . In the kidneys the urea is fjkrered out of thr blood and concentrated in thr Rhine . Urine can be safely stored in the bladder jr is released from thr body .
Figure 4 k. Page w29
Summary of the ornithine cycle
meaning of nephron
the functional unit of the kidney
What is ultrafiltration?
Filtration of the blood at a molecular level under pressure
What is the structure of the kidney
Most people have two kidneys . These are positioned on each side of the spine , just below the lowest rib . Each kidney is supplied with blood from a. Renal artery and is drained by a renal vein .
What is the role of the kidneys
The role of the kidneys is excretion .
The kidneys remove waste products from thr blood and produce urine . The urine passes out of the kidney down thr ureyer to the bladder here it can be stored until it is released .
Figure 1 page 30 a kidney in longitudinal section
In a ligitinudla section you can see thst the kidney consists of three regions surrounded by a tough capsule .
The outer region is called the cortex .
The inner region is called the medulla
The centre is the pelvis which leads into the ureter .
What is the fine structure of the kidney
The bull of each kidney consists of tiny tubules called nephrons .
Each kidney contains about ONE MILLION nephrons . Each nephron dyostys in the cortex t at a cup-shaped structure called the BOWMANS CALSULE Z. The remainder of thr nephrons is a coiled tube thst passes through the cortex , forms a loop down into thr medulla snd back to the correct , before joining a collecting duct thst passses down into thr ,radula .
Check figure 3 on page 30
A is fhe section through thr correct showing Bowman’s capsule and b how it might be drawn from the side ,
Learning tip of thr cortex t
The cortex t is a mass of tubules and glomeruli . You can tell which tubules are proximal tubules by the microvilli on the inner durgsve of the wall .the distal tubules are smaller ,
Blood supply are filtering in the arteries
The renal artery splits to form many afterrent arteriolar , which each lead to a knot of capillaries called fhe GLOMERULUS .
Blood from thr glomerulus continued into an efferent after joke whuch carries the blood to more capillaries surrounding the tedt tubule . These capillaries eventually flow together into thr renal vein
What is each glomerulus surrounded by ?
It is surrounded by the Bowman’s capsule . Fluid from the blood is pushed into the Bowman’s capsule by thr proceed of ultrafiltration.
What is figure 5 on page 31 showing
A the glomerulus snd
B bowman’s calsule
Par B is an enlarge,ent of the area outlined in blue part .
What is the filter in the kidney
It is the barrier between the blood in the capillary nad lumen of the Bosman’s capsule . This barrier consists of three layers which are all adapted to enable ultrafiltration
What Is the endothelium of the capillary
There are narrow gaps between the cells of the endothelium of thr capillary wall . The cells that f the endothelium also contain pores , called fe extraction . The gaps allow blood plasma and the substances dissolved in it to pass out of the capillary .
What is the basement membrane
Membrane consists of a fine mesh of collagen fibres and glycoproteins . passage of molecules with a relative molecular mass of greater than 690p0 . This means that more proteins (and all blood cells ) , are held in the capillaries of the glomerulus ,
What is the epithelial cells of the Bowman’s capsule
These cells called podocytes, have a specialised shape they ahve many finger like projections called major processes . On each major processes are minor process or foot processes thst hold the cells away for, the endothelium of the capillary . Those’d projections ensure that there’re are gaps bereeen the cells . Fluid from the blood I’m the glomerulus can pass brteeen these cells into the lumen of the Bowman’s calsule ,
What does the Bowman’s capsule lead into
INTO THE REST OF THE TUNULE WHICH HAS THREE PARTS
- proximal convoluted tubule
-loop of henle
-distal convoluted tubule
Where does thr fluid from the many nephrons enter
It enters the collecting ducts , which pass down through the medulla to the pelvis at the centre of the kidney .
Ultrafiltration
Ultrafiltration is the filtering of blood at fhe molecular level . Blood flows into thr glomerulus through afferenr arteriole whuch us wider than efferent arteriole that carries blood away from the glomerulus .
Ultrafiltration
Ultrafiltration is the filtering of blood at fhe molecular level . Blood flows into thr glomerulus through afferenr arteriole whuch us wider than efferent arteriole that carries blood away from the glomerulus .
Heheh difference in diameter means what
The difference in diameter , ensures that the blood in the capillaries of thr glomerulus maintains a pressure higher than the pressure in the bowman,s calsule . The pressure , difference tends to push fluid from the blood into thr Bowman,’s capsule that surrounds the glomerulus ,
What is filtered out of the blood ?
Blood plasma containing dissolved substances is pushed under pressure from the capillary into thr lumen of the BOWMANS capsule ,
What following substances are in the blood plasma
Water
Amino acids
Glucose
Urea
Inorganic mineral ions (sodium , chloride , potsssium )
What is left in the capillary and what does this mean
Blood cells and proteins are left in the capillary . The presence of proteins means that the blood has a very low (very negative) water potential .
This ensures that some of the fluid is retained in the blood m and this contains some of water and dissolved substances listed above . The very low water potential of the blood in the capillaries is important to help reabsorb water at a later stage .
What happens when the fluid from the Bowman’s capsule passes along the nephron tubule
Its composition is altered by selective re absorption - substances are absorbed back into thr tissue fluid snd blood capillaries surrounding the nephron ,
How is fluid altered in the proximal convoluted tubule
It is altered by the reabsoprtion of all sugars , most mineral ions and some water . In total 85% of the fluid is reabsorped here . The cells of these tubules have a highly folded surface producing a brush border which increases the surface area .
How is fluid altered in the proximal convoluted tubule
It is altered by the reabsoprtion of all sugars , most mineral ions and some water . In total 85% of the fluid is reabsorped here . The cells of these tubules have a highly folded surface producing a brush border which increases the surface area .
How is water potential decreased in the descending limb of the loop of henle
The water potential of the fluid is decreased by fhe addition of water ions and the removal of water .
In the ascending limb of the loop of henle how is the water potential increases
As mineral ions are removed by active transport
How is water potential increases in the collecting duct
The water potential is decrease again by the removal of water . The final product in thr collecting duct is urine l
How is water potential increases in the collecting duct ?
The water potential is decrease again by the removal of water . The final product in thr collecting duct is urine l
This process ensures that urine the final product has what
Has a low water potential of. The urine therefore has a higher concentration of solutes than is found in the blood and tissue fluid . Urine passes into the pelvis and down the ureter to the bladder ,
What processes do reabsoprtion include
Reabsoprtion involves active transport and cottons
Or to. The cell lining the proximal convoluted tubules are specialised to achieve this reabsoprtion .
What processes do reabsoprtion include
Reabsoprtion involves active transport and cottons
Or to. The cell lining the proximal convoluted tubules are specialised to achieve this reabsoprtion .
One adaptation of fhe cell surface membrane for selective reabsoprtion
The cell surface membrane in contact with the tubule fluid is highly folded to form microvilli . The microvilli increase the surface area for reabsoprtion.
One adaptation of fhe cell surface membrane for selective reabsoprtion
The cell surface membrane in contact with the tubule fluid is highly folded to form microvilli . The microvilli increase the surface area for reabsoprtion.
Second reabsoprtion of selective reabsoprtion
The cell surface membrane in contact, also contains special contransported proteins that transport glucose or amino acids , in association with sodium ions from the tubule into thr cell .
How is the opposite membrane of the cell adapted for selective reabsoprtion
The opposite membrane of the cell close to the tissue fluid and blood capillaries is also folded to increase its surface area . This membrane contains sodium / potsssium pumps that pump sodium ions our of fhe cell and potassium ions into the cell .
How is fhe cell cytoplasm adapted for selective reabsoprtion
The cell cytoplasm has many mitochondria . This indicates that an active or energy- readying process is involved p, because many mitochondria wikk produce a lot of ATP .
Check page 33 reabsoprtion figure 1
It explains how glucose and amino acids are selectively re absorbed . Thr movement of sodium ions and glucose into the cell is driven by the concentration gradient created by pumping sodium ions out of the cell is driven. The sodium ions move into the cell by facilitated diffusion but uthey do transport glucose or amino axis against their concentration gradient . This is sometimes called secondary active transport.
Mchianism of reabsoprtion figure q page re parti 2
The movement of these substances reduces the water potential of the cells so that the alter is drawn h from the tubule by osmosis , As fhe substances move through to the blood , the water follows . L
Larger molecules such as small proteins may have enetereenth tubule , can be reabsorbed by endocytosis ,
Reabsoprtion of water carat fact
Each minute 125 kf fluid is filleted from thr blood and enters the nephrons , after selective rewbsoprion in rhenorisimwl convoluted tubule , about 45 of fluid is left . By the time this fluid reaches the b,assee , the volume has dropped about 1.t cm3 ,
What does the loop of henle consist of
It consists of a descending limb that descended into the medulla and an ascending limb thst ascends back out to the cortex .
What does fhe arrangement of the loop of henle allow
The arranagemenr or the loop of henle allows mineral ions h sodium snd chloride ions ) to be transferred form the ascending limb into the descending limb. The overall effect is to increase the concentration of mineral ions inori the tubule fluid . Which has a similar effect upon the concentration of mineral ions into the tissue fluid . This rigesnrhe tissue fluid in the medulla q very low h very nevairve j water
Potential . l
Loop of henle part one
As mineral ions enter the descending limb , the concentration of the fluid in th descending limb rises . This means that its water potential decreases (becomes more negative ) . It becomes increasingly more negative the deeper the tubule descends into the medulla ,
Loop of henle part two
As the fluid rises up the ascending limb into, mineral ions leave the fluid . At the base , this movement is by diffusion . However m higher up the ascending limb , active transport is used to move mineral ions out of the. The upper portion of thr ascending limb is also impermeable to water l
Loop of henle part three
The effect of these ionic movement is to create a higher water potential in the fluid of the ascending limb . It also dec Reese’s the water potential nit all in the tissue fluid of the medulla . The water potential of the ttissue fluid becomes lower (much more negairge ) towards the bottom of the loop of Henle ,
Loop of henle part four
As fluid passes down fhe collecting duct m it passes through tissues us with an ever deceasing water potential . Therefore , there is always a water potential gradient between the fluid in the collecting duct and that in the tissues . This allows water to be moved out of the collecting duct and into the tissue fluid by osmosis .
What is the arrangement of the loop of henle known as
It is known as a hairpin countercurrent multiplier system , the overall effect or this arrangement is to increase the effeifency of transfer of mineral ions from the ascending limb to the descending limb in order to create the water potential gradient seen int he medulla l
The collecting duct (1)
From the top of the ascending limb to thr tubule fluid passes along a short distal convoluted tubule where active transport is used to adjust the concentrations of various of mineral ions from. From here thr fluid flows into the collecting duct .
Collecting duct part two
At this stage the turbulence fluid still contains a lot of water - it has a high water potential Collecting duct carries the fluid back down through thr medulla to thr pelvis . Remember thst the tissue fluid in the medulla has a low water potential thst becomes even lower deeper into thr medulla l
Collecting duct (3)
As the tubule fluid pssses down the collecting duct m water moved by osmosis from thr tubule fluid into the surrounding tissue . It then enters thr blood capillaries by osmosis and is carried away .
What does the amount of water reabsorbed depend on
Depends on the permeability or the collecting duct walls . Only 1.5-2.0 of fluid (urine ) reaches the pelvis each day . By time the urine reaches the pelvis , it has a low (very negative j water oitenitwk and the concentration of mineral ions and urea is higher than in blood .
Figure 2 page 35 line 1
Glucose decreases as it is selectively reabsorbed from the proximal tube
Figure 2 page 35 line 1
Glucose decreases as it is selectively reabsorbed from the proximal tube
Figure 2 page 35 line 2
Sodium ions diffuse;into the descending limb of the loop of Henle , causing the concentration to rise. They are then pumped out of the ascending limb so the concentration falls ,
Figure 2 page 35 line 3
The urea concentration rises as water is withdrawn from the Tahoe . Urea m dmslso actively moved into thr tubule fluid.
Figure 2 page 35 line 3
The urea concentration rises as water is withdrawn from the Tahoe . Urea m dmslso actively moved into thr tubule fluid.
Figure 2 page 35 line 4
Sodium ions are removed from the tubule , but their concentration rises as water is removed from the tubule and potsssium ions increase in concentration as water is removed . Potsssium ions see also actively transpired into the tubule ti be removed in urine m
Antipyretic hormone (ADH)
A hormone rust on trolls the permeability or the collecting duct wallls
Osmorecepetorn
A sensory receptor thst detects changes in water potential ,
What is osmoregulation
Osmoregulation is fhe control of the water potential in the body . Water potential is the red ended of water to move from ne place to another l
What does osmoregulation involve
Controlling levels of both water and salt in the body . The correct water balance between cells and the surrounding fluids must be maintained to prevent water everting the cells snd causing lysis or leaving cells and causing crenation .
How does the body gain water
Food
Drink
Metabolism (e.g respiration )
Water is lost from the body in urine sweat , water vapour is exhaled air and teaches l
The gains and losses of water must be balanced . How is this balances
The kidneys act as an effector to control the water content of the body and the salt concentrations in the body fluids ,
On a cool day or when you have drunk a lot of fluid , the kidneys will produce a large Fiume of dilute urine .
Alternatively on a hot day what happens
When you have drunk very little , the kidneys kidneys ill produce smaller volume of more concentrated urine ,
How do the kidneys alter the volume or urine produced
By altering the permeability of the collecting ducts . The walls of the collecting ducts can be made more or less permeable according to the needs of the body .
What happens if you need to conserve less water
(On a cool day or when you have drunk a lot of fluid ), the walls of the collecting duct becomes less permeable , this means that less water is reabsorbed and a greater volume of urine will be produced ,
If you need to conserve more water (on a hot day or when you have drunk very little
The collecting duct walls are made more permeable so that more water can be ab sieved into the goood .. you will produce a smaller volume of urine .
The cells in the walls of the collecting duct respond to th over of ADH int he boood
These cells have membrane bound receptors for ADH . The ADH binds to rhesus receptors and causes a chain of enzyme - controlled reactions inside the cell ( an example of cell signalling ). The end revelry of these reactions is to cause vesicles containing water permeable channels (aquaplrins ) to fuse with the cell surface membrane . This makes rhesus walls more permeable to water ,
The cells in the walls of the collecting duct respond to th over of ADH int he boood
These cells have membrane bound receptors for ADH . The ADH binds to rhesus receptors and causes a chain of enzyme - controlled reactions inside the cell ( an example of cell signalling ). The end revelry of these reactions is to cause vesicles containing water permeable channels (aquaplrins ) to fuse with the cell surface membrane . This makes rhesus walls more permeable to water ,
What happens when the level of ADH in the blood rises
More water permeable channels are inserted . This allows more water to reabsorbed , by osmosis into the blood . Less urine is produced and the urine has a lower water potential .
What Halle s h we fhe level or ADH in the blood falls
Then the cell surface membrane folds inwards (invagjantes ) to create a new vehicle that remove water - permeable channnels from the membrane ,
This makes the walls less permeable and less water is reabsorbed , by osmosis , into the blood . More water passes on down the collecting duct , to form a greater volume of urine which is more dilute (higher water potential ) .
Page 36 figure 1 1
ADH is detected by cell surface receptors
Page 36 figure 1 1
ADH is detected by cell surface receptors
Page 36 figure 1 2
Enzyme - controlled reactions is
Page 36 figure 1 2
Enzyme - controlled reactions
Page 36 figure 1 2
Enzyme controlled reactions
Page 36 figure 1 2
Enzyme controlled reactions
Page 36 figure 1 2
Enzyme controlled reactions
Page 36 figure 1 3
Vesicles containing water permeable channels (aquapleins) fuse to membrane .
Page 36 figure 1 4
More water can be reabsorbed
Adjusting the concentration of ASH in the boood
The hypothalamus in the brain contains specialised cells called osmoreceptors these are the sensory receptors that detect the stimulus - they water potential of the blood is.
Adjusting the concentration of ASH in the boood
The hypothalamus in the brain contains specialised cells called osmoreceptors these are the sensory receptors that detect the stimulus - they water potential of the blood is.
Adjusting concentration of ADH in the blood neurosecretoryb
The neurosecretory cells are specialised neurones nerve cells , thst produce snd release ADH . The ADH is manufactured in the cell body which lies no h hypothalamus. The ADH modes down the axon to the terminal bulb in the posterior pituitary gland where it is stored in vesicles l
Hgghg
These cells ewwpine to the effftw or womowiw . When the water porneiral or the blood is low gene negative fhe osmoreceptors deoow lose water by osmosis and when I . And as result rhey sirnuoate the neurosecretoey cekks in the fhe hypothalamus .
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These cells ewwpine to the effftw or womowiw . When the water porneiral or the blood is low gene negative fhe osmoreceptors deoow lose water by osmosis and when I . And as result rhey sirnuoate the neurosecretoey cekks in the fhe hypothalamus .
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These cells ewwpine to the effftw or womowiw . When the water porneiral or the blood is low gene negative fhe osmoreceptors deoow lose water by osmosis and when I . And as result rhey sirnuoate the neurosecretoey cekks in the fhe hypothalamus .
What are the neurosefreotu cells
They are specialised neurones (nerve cells ) that todo ur and release ADH . The ADH is manufactured in the cell body which lies in the hypothalamus . ADH moved down the axon to the termina bull in the posterior pottu sory gland , where it is stored in vesicles .
When the neeurosecrroeu cells are stimulated by the osmorefpeorts
They carry the axfion potentials down axons and caused the release of ASH by edofyrosis m
ADH enters RHE blood capillaries ruinjintnthough the posterior pick unitary gland
It is transported around the body and act on the cells for he collecting ducts )it’s target cells ) . Once the water potential of the blood rises again , less ADH is released . Sasha is sowly broken down A it is a bald life or about 2 minutes za therefore the ADH present in the blood is broken down and the collecting ducts will receive less information .
GIVURE 3 how the level of ADH is controlled by negaitve feedback
increase in water potential of blood
-detected b y osmoreceptors in hypothalalmus .
-less ADH relesed from posterior pituirary .
-Collecting duct walls permeable .
-less water reabsorbed into blood (nad more unrine produced ) .
-Decrease in watee rpotential of blood .
decrsdr in water potential of blood
-detected by osmoreceptors in hypothalamus .
-more ADH relesed from psoterior pituitrary .
-Collecting duct alls more premable
-More water reabsorbed inot blood ( nd elss urine porduced )
INCREASE IN WATER POTENITAL OF BLOOD L
what happenns if the kidneys fail
if the kidneys fail completely , they are unable to regulate the levels of water and electrolytes (substances tht form charged particles in water ) , in the body or to remove waste products sucha s urea from the blood . THIS IWLL RAPIDLY LEAD TO DEATH .
how can kidney function be assessed
kidney function can be assessed by estimaitng the glomerular filtration rate (GFR) and by analysisng the urine for substances such as proteins . Proteins in the urine indicate the filtration mechanism has been damaged .
what is the gfr a measure of and give the reading levels
it is a measure of how much fluid passes into the nephrons .
A NORMAL READING - is in the range of 90-120cm3min-1.
a figure below 60cm3min-1 indicates that there may be some form of chronnic kidney disease .
-A figure below 15cm3 min-1 indicaes kindey failure and a need fo rimmediate medical atention .
give the causes for kindey failure
the possible causes of kidney failure include diabetes , mellitus , type 1 and type 2 suagr diabeted
hert disase
hypertension ifneciton .
what are the two main treatments for kindey failure
renal dialysis and kindey transplant
what is renal dialysis (1)
renal dialysis is the m ost common treatment for kidney failure . Waste products , excess fluid and mineral ions are removed from the blood by passing it over a partially permeable dialysis membrane that allows the exchange of substances between the blood and dialysis fluid .
what is renal dialysis (2)
the dialysis fluid contains the correct concentrations of mineral ions , urea , wate and other substances ofund in blood plasma .
-Any substances in excess in the blood diffuse across the membran einto the dialsyiss fluid . Any substances that are too low in concentration diffuse into the blood from the dialsysis fluid .
first type of renal dialysis - haemodialysis (1)
blood from an artery or vein is passed into a machine that contains an artificial dialsysis membrane shaped to form many artifical capillaries , which increase the surace area fo exchange .
first type of renal dialysis - haemodialysis (2)
heparin is added to avoid clotting . The artificial capillaries are surrounded by dialysis fluid , which flows in the opposite direction to the blood ( a countercurrent ) . This improves the efficiency of exchange . Any bubbles are removed beforethe blood is returned to the body via a vein .
how many times a week is haemodialysis usually performed
haemodialysis is usually performed at a clinic two or three times a week for several hours at each session . Some patients learn to carry it out at home .
second type of renal dialysis - peritoneal dialysis (PD)
The dialysis membrane is the body’s own abdominal membrane (peritoneum ) . First , a surgeon implants a permanent tube in the abdomen .
-Dialysis solution is poured through the tube and fills the space between the abdominal wall and organs . After several hours , the used solution is drained from the abdomen .
where can pd be carried out
pd can be carried out at home out at work , the patient can walk around while having the dialysis , the method is sometimes called ambulatory PD .
DIALYSIS MUST BE COMBINED WITH A
CAREFULLY MONITORED DIET .
what is a kidney transplant
a kidney transplant is the best life - extending treatments for kidney failure . This invovles major surgery . While the pateint is under anaesthesia , the surgeon implants the new organ into the lower abdomen , and attavhes it to the blood supply and the bladder .
-PATIENTS are given immunosupressant drugs to help prevent their immune system recognising the new organ as a foreign object and rejecting it .
advanatages of kidney transplant
freedom from time - consuming renal dialysis .
-feeling physically fitter .
-improved quality of lfie - able to travel .
-improved self - image - no longer have a feeling of being chronically ill .
disadvanatage of kidney transplants
-need to take immunosuprressant drugs .
-need for major surgery under general anaesthetic .
-need for regular checks for signs of rejection .
-side effects of immunosuppressant drugs - fluid retention , high blood pressure , susceptibility to infections .
why can you test the urine for substances
moelcules with a relative molecular mass of less than 69000 can enter the nephron . Any metabloic product or other substance in the blood can therefore be passed into the urine if it is small enough . If these substances are not reabsorbed further down the neprhon they can be detected in urine .
how can urine be tested
-glucose in the diagnosis of diabetes .
-alcohol to determine blood alcohol levels in drivers .
-many recreational drugs (test may be carried out as a random , test at work - especially where there are safety issues related to the type of work )
-human chorionic gondootrophin hcg pregnancy testing
anabolic steroids improper use in sporting competitions .
pregnancy testing
-once a human embryo is implanted in the uterine lining , it porduces hormone called HCG , it is a relatively small glycoprotein , with a molecular mass of 36.7 k . that can be found in urine as early as six days after conception .
Pregnancy - testing kits use monoclonal antibodies which bind ot hCG in urine .
testing for anabolic steroids (1)
anabolic steroids increase protein synthesis within cells , which results in the build-up of cell tissue , especially in the muscles non medical uses for nabolic steroids re controversial , becaise they cna give advantage in competitive sports and they have dangerous side effects .
how can ou test for anabolic steroids
all major sporting bodies ban the use of anabolic steroids , they have a hald life of abou 16 hrs and remian in the blood for many days , they are realitvley smallmoelcuels and cn enter the nephrone asily - u can analyse urine sample fo rhti using GC .
