PHISIOLOGY

(SBF 3013)

SEMESTER 2 2011/2012

PBL REPORT : URINARY SYSTEM

DATE OF SUBMISSION : 18th May 2012

LECTURER’S NAME : DR NORJAN BINTI YUSOF

GROUP : A

GROUP MEMBERS :

MARLISA BINTI SAU D20101037418

NUR HAYATI BINTI YUSOFF D20101037439

NORFARRAHDILAH BINTI AMIR D20101037438

SITI SALWA BINTI ABDULLAH D20101037439

INTRODUCTION

Problem-based learning (PBL) is an exciting way to learn biology and is readily

incorporated into large classes in a lecture hall environment. PBL engages students in solving

authentic biological case problems, stimulating discussion among students and reinforcing

learning. A problem-based learning environment emulates the workplace and develops self-

directed learners. The use of problem-based learning as a central instrument of teaching has

advantages. These advantages are presenting students with a more natural format for learning,

confronting many different resources to encourage critical thinking and promoting improvement

of the student-tutor relationship. Development of critical thinking in students is one of the main

desired outcomes of PBL which can be achieved in the right environment. From the task given to

us, we started to understand the problem with FILA chart.

As in the task, our first assumption that she has facing a health problem with her kidney.

From the symptoms that she faced and the biological test result, she is liked a person that have a

kidney failure. From this problem, we make discussion to find all the solution to get as much

information as possible to strengthen our assumption. With loss of kidney function, there is an

accumulation of water, waste, and toxic substances in the body, that are normally excreted by the

kidney. Loss of kidney function also causes other problems such as anaemia and high blood

pressure. When our kidneys fail, harmful wastes build up in body, our blood pressure may rise,

and body may retain excess fluid and not make enough red blood cells. When this happens, we

need treatment to replace the work of your failed kidneys.

As we know, the urinary system is the organ system that produces, stores, and eliminates

urine. In humans it includes two kidneys, two ureters, the bladder and the urethra. These organs

control the amount of water and salts that are absorbed back into the blood and what is taken out

as waste. The female and male urinary system are very similar, they differ only in the length of

the urethra. Each kidney and contains filtering units called nephrons. Each nephron is made of a

glomerulus and a tubule. The glomerulus is a miniature filtering or sieving device while the

tubule is a tiny tube like structure attached to the glomerulus.

STRUCTURE OF KIDNEYS

The kidneys are located near the vertebral column at the small of the back which the left

kidney lying a little higher than the right. Each is identical in structure and function. They are

bean-shaped, about 10 cm long and 6.5 cm wide. Each kidney comprises an outer cortex and an

inner medulla. The kidney is supplied with oxygenated blood via the renal artery and drained of

deoxygenated blood by the renal vein. The main functional unit of the kidney is the nephron.

There are approximately one million nephrons per kidney. The nephron contains a cluster of

blood vessels known as the glomerulus, surrounded by the hollow Bowman's capsule. The

glomerulus and Bowman's capsule together are known as the renal corpuscle. The glomerulus is

mechanically filters blood and the Bowman's capsule allows the diffusion of molecules from the

blood. Bowman's capsule leads into a membrane-enclosed, U-shaped tubule called loop of Henle

that empties into a collecting duct. The loop of Henle function to countercurrent exchange which

maintain the concentration gradient. The collecting ducts from the various nephrons merge

together, and ultimately empty into the bladder.

FUNCTION OF KIDNEYS

The kidneys' function is to filter the blood. All the blood in our bodies passes through the

kidneys several times a day. The kidneys will remove wastes, control the body's fluid balance,

and regulate the balance of electrolytes. As the kidneys filter blood, they create urine, which

collects in the kidneys' pelvis that drains down tubes called ureters to the bladder. Other than

that, kidney also produces enzyme and hormone which help to control our blood pressure and

also make red blood cells and help maintain our blood composition and pH level. There are three

functions of nephrons which are glomerular filtration of water and solutes from the blood,

tubular reabsorption of water and conserved molecules back into the water and tubular secretion

of ions and other waste products from surrounding capillaries into distal tubule.

Urine formation begins with the process of filtration that takes place through the

semipermeable walls of the glomerular capillaries which are almost impermeable to proteins and

large molecules. As blood courses through the glomeruli, much of its fluid, containing both

useful chemicals and dissolved waste materials, soaks out of the blood through the membranes

by osmosis and diffusion where it is filtered and then flows into the Bowman's capsule. This

process is called glomerular filtration. The water, waste products, salt, glucose, and other

chemicals that have been filtered out of the blood are known collectively as glomerular filtrate.

The glomerular filtrate consists primarily of water, excess salts primarily Na+ and K+, glucose,

and a waste product of the body called urea. Urea is formed in the body to eliminate the very

toxic ammonia products that are formed in the liver from amino acids. Since humans cannot

excrete ammonia, it is converted to the less dangerous urea and then filtered out of the blood.

Urea is the most abundant of the waste products that must be excreted by the kidneys.

Reabsorption is the movement of substances out of the renal tubules back into the blood

capillaries located around the tubules called the peritubular capillaries. Substances reabsorbed

are water, glucose and other nutrients, and sodium (Na+) and other ions. Reabsorption begins in

the proximal convoluted tubules and continues in the loop of Henle, distal convoluted tubules,

and collecting tubules. Large amounts of water are reabsorbed back into the bloodstream from

the proximal tubules back into the blood capillaries.

The blood sugar is entirely reabsorbed back into the blood from the proximal tubules. It is

actively transported out of the tubules and into the peritubular capillary blood. Sodium ions (Na+)

and other ions are only partially reabsorbed from the renal tubules back into the blood. For the

most part, however, sodium ions are actively transported back into blood from the tubular fluid.

The less the salt intake, the greater the amount of sodium reabsorbed back into the blood, and the

amount of salt excreted in the urine decreases.

Secretion is the process by which substances move into the distal and collecting tubules

from blood in the capillaries around these tubules. In this respect, secretion is reabsorption in

reverse. Whereas reabsorption moves substances out of the tubules and into the blood, secretion

moves substances out of the blood and into the tubules where they mix with the water and other

wastes and are converted into urine. These substances are secreted through either an active

transport mechanism or as a result of diffusion across the membrane. Substances secreted are

hydrogen ions (H+), potassium ions (K+), ammonia (NH3), and certain drugs. Kidney tubule

secretion plays a crucial role in maintaining the body's acid-base balance, another example of an

important body function that the kidney participates in.

SYMPTOMS OF KIDNEY FAILURE

The symptoms of kidney disease tend to appear after a long period of time, so people

thought they are normal responses to stress.  In addition to the symptoms, people may find that

they have high blood pressure. High blood pressure occurs when the blood contains more water

and salt than normal, this increases the pressure in blood vessels. Knowing the symptoms of

kidney disease help us recognize the problems facing by our roommate, so she can get proper

treatment to cure her illness.

When kidneys are failing, excess fluid builds up in the body. This led to a condition

known as edema, which is swelling in the hands, ankles, feet, or face (especially around the eyes,

when you just wake up). Fluid can also collect in the lungs, which may cause shortness of breath.

Kidney failure also can slow down production of a hormone called erythropoeitin, which leads to

a low red blood cell count. This causes anemia, a common and treatable complication of kidney

disease that can make people feel tired very quickly. Anemia can prevent brain from getting

enough oxygen. When this happen, most patient may feel difficult to sleep, difficult to

concentrate, and dizziness.

As we know, the kidney also makes urine, so, if one have malfunction kidney, this cause

urine to change. Urination problems include foamy or bloody urine, more or less urine than

usual, a change in how often we urinate, or pressure or difficulty urinating. Kidneys remove

waste from the bloodstream, so when kidneys fail, the build up of waste in bloodstream can

cause skin rashes or severe itching. Apart from that, people with kidney failure may feel food

taste different (metallic taste), they may loss of appetite because of this bad taste. Vomiting also

is one of the symptoms of kidney failure. Build up of waste products in kidney has cause

cramped. Based on the research, we can conclude that our roommate has malfunction kidney

because she show several symptoms like above.

THE FUNCTION OF ELEMENTS IN BIOCHEMICAL TEST

The biochemical test that have been done using blood sample involved some important

elements used by our body. The elements are blood creatinine, blood urea nitrogen, sodium,

potassium, calcium, phosphate, white blood cell and albumin. These elements play a very

important role in order to keep our body well functioned.

The first element is the blood creatinine. Blood creatinine or its scientific name methyl

guanidine-acetic acid is a compound comprised of three amino acids which are arginine, glycine

and methionine. Creatinine is a natural by-product of muscles doing work in our body. It starts

out as creatine phosphate and ends up as a waste product in our blood which then eliminated in

urine. This blood creatinine plays many functions to keep our body healthy, one of it is to create

energy. Creatine that being stored in muscle tissue is able to bond with phosphorus to form

creatine phosphate. Creatine phosphate is used to produce additional ATP (adenosine

triphosphate) which used to transport chemical energy within cells for metabolism process by

combining with ADP (adenosine diphosphate). By helping to create more ATP, this creatine

phosphate aids in allowing the body to function at maximum exertion for longer periods of time.

Creatinine also helps further protein synthesis. Additional creatine in our systems can put

the body into a more "anabolic" state. In a more anabolic state, protein synthesis can occur at a

greater level, thus allowing muscle to benefit greatly from this increase. Besides, creatinine also

can ease muscle soreness that caused by lactic acid build up after a hard workout. Creatine will

bond to a certain hydrogen ion to slow the production of lactic acid during workouts, thus

alleviating some soreness.

The second element is sodium. Sodium is a mineral occurs naturally in most foods such

as table salt, baking soda, monosodium glutamate (MSG), various seasonings, additives,

condiments, meat, fish, poultry, dairy foods, eggs, smoked meats, olives, and pickled foods. In

our body, sodium element helps us to maintain our blood pressure and also function of muscles

and nerves at normal level. Other than that, sodium used to regulate fluids which the blood

volume and blood pressure in our body and it also plays an important role in transmission of

nerves impulses and muscles contraction. Sodium is also critical for the functioning of regulation

the acid and base balance in the body.

Next element found in biochemical test is potassium. Potassium is a mineral involved in

electrical and cellular body functions. Potassium is a very important mineral for the proper

function of all cells, tissues, and organs in the human body. It is also an electrolyte, a substance

that conducts electricity in the body, along with sodium, chloride, calcium, and magnesium.

Potassium is crucial to for the normal electrical activity of the heart and plays a key role in

skeletal and smooth muscle contraction, making it important for normal digestive and muscular

function. Potassium is essential for maintaining proper fluid balance and also the regulation of

the acid-base balance. Besides, it assists in protein synthesis from amino acids and in

carbohydrate metabolism where it converts glucose into glycogen for muscle fuel.

Another element found in the test is calcium. Calcium is an essential bulk mineral which

makes up bones and teeth in our body whereas the rest of the calcium can be found in nerve

cells, body tissues, blood, and other body fluids. The body stores the calcium in two ways, one it

is an exchangeable pool which allows the calcium to be released into the blood stream when

dietary intake is low and another way is the remainder of the calcium that is stored in a non-

exchangeable reserve in the bones. Calcium is essential for the transmission of information along

the nerves and is used in the contraction of muscles. Moreover, calcium keeping the bones and

teeth strong over human lifetime other than helping in blood clotting and regulating blood

pressure. This element plays an important role in the action of a number of hormones particularly

those associated with the thyroid and parathyroid glands. In addition, calcium also prevents

muscle or leg cramps by squeezing and relaxing body muscles and the most important role is to

maintain normal body growth and development.

Phosphate is an element resulting from the combination of the oxygen with phosphorus.

Phosphorus is a natural mineral and is one of the main components, along with calcium, that

forms bone and teeth. Phosphate also provides energy for our body. The primary role of

phosphate is to help form strong bones and teeth in the human body. It’s also found in other

organs throughout the body and it helps filter waste from the kidneys and plays a vital role in the

production and storage of energy in the body. In its basic form, phosphorus is also responsible

for maintaining the balance of other nutrients since it combines with other minerals to form

phosphate salts or compounds.

Another important function of phosphate groups in human body is by providing a source

of energy for cells to do work including mechanical, chemical and transport. Mechanical work

includes such things as controlling the flow of cytoplasm within the cell, moving chromosomes

during reproduction, or contracting during muscle movements. Chemical work involves the

metabolic reactions that would not occur spontaneously. Transport work involves the pumping of

substances in and out of a cell. In most cases, a phosphate-containing compound called

adenosine triphosphate (ATP) provides the power for all types of cellular work. Phosphorus is

also an important component of the nucleic acids DNA and RNA, which are responsible for the

storage and transmission of genetic information. Combined with lipids, phosphorus is an

important structural component of cell membranes. Phosphorus also functions in maintaining

acid-base balance by acting as one of the body's important buffers.

Other than that, white blood cell also important in our body. White blood cell or

leukocytes are cells of the immune system involved in defending the body against infectious

disease and foreign materials. White blood cells are found throughout the body including the

blood and the lymphatic system. White blood cells work best in defending the body against

bacterial parasitic and fungal infections where different type of the cells used to fight different

infections. The most common type of white blood cells is neutrophil and eosinophil. Other than

neutrophil and eosinophil, the basophil responsible for allergic and antigen responses. These are

the cells that release the histamines and cause inflammation during an allergic reaction. White

blood cells protect our body by providing immunity against disease possible. These lymphocytes

will create antibodies that bind themselves to the pathogens or invaders in our system and then

enable their destruction. In addition, white blood cells especially monocytes act as the vacuum

cleaners in body systems. After an infection has been killed or destroyed, these cells will clean

up the damage left behind. They will actually ingest dead cells, tissue debris and old red blood

cells that left behind after the body has battled the infection.

The last element found in the biochemical test is the albumin. Albumin is a kind of water

soluble protein which is found in numerous forms in the natural world. Albumin is an essential

protein which is very important to maintain good health of living organisms. A number of plants

and animals have albumin in them or may secrete the same in the form of waste. In human

beings, albumin is present in the blood as well as the urine. In human beings, albumin present in

the blood, where it performs a very important function of transporting essential fatty acids from

the fats to the muscle tissue. Another function of albumin is that it regulates the process of

osmosis where it maintains the "osmotic pressure" that causes fluid to remain within the blood

stream instead of leaking out into the tissues. It also acts as a plasma carrier by non-specifically

binding several hydrophobic steroid hormones and as a transport protein for hemin and fatty

acids. Also, albumin transports all kinds of substances through the bloodstream such as

hormones and drugs. Lastly, albumin provides the body with proteins which are needed to repair

the tissues and maintain growth.

THE EFFECT OF INCREASING OR DECREASING EACH OF ELEMENTS IN

BIOCHEMICAL TEST.

The first element that found in table of biochemical test is blood creatinine. What do high

creatine levels mean? If the ability of the kidneys to filter fluid within the body declines, creatine

urea and urate will increases. The most common reasons for developing raised creatine levels

will be when the filtration mechanism becomes gradually damaged by long-term raised blood

pressure or diabetes. There may be a rise in blood creatine levels as the kidney tries to deal with

the breakdown products of proteins in our bodies. As the kidneys become increasingly unable to

cope, so the creatine level rises.

The second one is potassium. The kidney normally removes excess potassium from the

body. Kidneys are responsible for filtering out excess electrolytes from the body. When its are

not working properly, they allow potassium to accumulate, often leading to hyperkalemia. This

may occur in people with advanced stages of Chronic Kidney Disease (CKD). If we have kidney

disease, doctor may recommend a potassium-restricted diet.

Other than that, blood sodium testing is used to detect abnormal concentration of sodium,

termed hyponatremia (low sodium) and hypermatremia (high sodium). A high blood sodium

level is almost due to inadequate water intake and dehydration. This may be due to caused by too

little Antidueretic hormone (ADH). Body normally excretes excess sodium, so the concentration

in the urine may be elevated. As we know, in kidney system, the amount of water and salts

reabsorbed is actually controlled by endocrine system example ADH. If ADH is too little,

reabsorbtion will not function in proper manner. So that, sodium level is high in urine and give

some malfunction of kidney.

High level of urine calcium may be due to chronic kidney disease. This may caused by

hyperparathyroidism. If we have kidney failure, our blood calcium level can become chronically

high. Like calcium, phosphate also is a mineral that strengthens the bones. Normal kidneys help

to keep right amount of phosphate in the blood. When kidneys fail, phosphate builds up in the

blood. In kidney patients phosphate levels can exceed 4.5mg/dL. To keep phosphate levels down

people with kidney failure should follow a healthy diet and in particular, avoid phosphate-rich

food such as nuts and meats.

Moreover, the presence of high white blood cell count in the urine indicates a bacterial

infection. High blood cell count present in urine is in fact a major symptom of urinary treat

infection. This infection starts from the urinary tract and spreads to the kidneys. Kidneys are

filters of the body which filter blood and prevent it cells from entering the urine. But when the

kidneys are not functioning normally, they can get infected and this malfunction can lead to

passage of some of the white blood cell into the urine.

In contrast with other, the albumin level is decrease from normal. Albumin is a protein

made by the liver. Low levels of albumin can reflect diseases in which the kidneys cannot

prevent albumin from leaking from the blood into the urine and being lost. In this case, the

amount of albumin or protein in the urine also may be measured. Diseased kidneys sometimes

lose large amounts of albumin into the urine faster than the liver can produce it. Decreased

albumin may occur when body does not get or absorb enough nutrients such as after weight-loss

surgery.

BLOOD UREA NITROGEN (B.U.N) TEST

The blood urea nitrogen or B.U.N test is a measure of the amount of nitrogen in the blood

in the form of urea that come from the body waste product. It is also a measurement of renal

function to see how well our kidneys are working. If our kidneys are not able to remove urea

from the blood normally, B.U.N level will rises. Diseased or damaged kidneys cause an increase

B.U.N because the kidneys are less able to clear urea from the bloodstream. In conditions in

which renal perfusion is decreased, such as hypovolemic shock or congestive heart failure,

B.U.N levels will rise. A patient who is severely dehydrated may also have a high B.U.N due to

the lack of fluid volume to excrete waste products. Because urea is an end product of protein

metabolism, a diet high in protein, such as high-protein tube feeding, may also cause the amount

of B.U.N to increase. The effect that happens when the B.U.N levels increase are impaired renal

function, congestive heart failure as a result of poor renal perfusion, dehydration, shock,

hemorrhage into the gastrointestinal tract, acute myocardial infarction, stress and excessive

protein intake or protein catabolism.

Liver disease, especially severe liver disease, can lower both B.U.N and creatinine levels

in our body. Pancreatic insufficiency can also cause decreased levels of B.U.N in our body.

Pancreatic insufficiency manifests when our pancreas does not secrete the proper amount of

chemicals and digestive enzymes for normal digestion to occur. Severe pancreatic deficiency can

lead to impaired absorption of nutrients by our intestines which lead to decrease in the B.U.N

levels. Other than that, overhydration causes a decreased BUN. When a person has syndrome of

inappropriate anti-diuretic secretion (SIADH), the anti-diuretic hormone responsibles for

stimulating the kidney to conserve water causes excess water to be retained in the bloodstream

rather than being excreted into the urine. SIADH can cause the BUN level, along with other

important substances, to decrease because the fluid volume of the bloodstream may significantly

increase.

CONCLUSION

After having a great discussion about the BFF’s case in the problem-based learning

session, we totally agreed that the roommate is having a disease involving her kidneys where

they cannot carry out their function very well. The kidney failure is described as a decrease in

glomerular filtration rate. This kidney failure can be causes by acute tubular necrosis (ATN),

autoimmune kidney disease which includes acute nephritic syndrome and interstitial nephritis,

decreased blood flow due to very low blood pressure which results from burns, dehydration and

also injury and lastly the infections that directly injure the kidney.

The symptoms that the roommate is having such as serious health decline, headache, loss

of appetite, vomiting and swelling found in her feet and face shows that she is really having

problem with her kidneys. Vomiting is causes by dehydration where the body loss of fluid. The

abnormal blood flow to and from the kidney due to obstruction of the renal artery or vein causes

her body part such as face and feet to swell.

When the kidneys fail, the roommate can have treatments to replace the work kidneys

normally perform. One of the treatments is haemodialysis. Haemodialysis cleans and filters the

blood using a machine to temporarily rid the body of harmful wastes, extra salt, and extra water.

Haemodialysis helps control blood pressure and helps the body keeps the proper balance of

important chemicals such as potassium, sodium, calcium, and bicarbonate. Other than

haemodialysis, she can have the peritoneal dialysis to removes wastes, chemicals, and extra

water from body. This type of dialysis uses the lining of abdomen, or belly, to filter her blood.

This lining is called the peritoneal membrane and acts as the artificial kidney. There are three

types of peritoneal dialysis that available are Continuous Ambulatory Peritoneal Dialysis

(CAPD), Continuous Cycler-assisted Peritoneal Dialysis (CCPD) and combination of CAPD and

CCPD. Another choice of treatment that she can have is the kidney transplant. Kidney

transplantation surgically places a healthy kidney from another person into patient body. The

donated kidney does enough of the work that her two failed kidneys used to do to keep her

healthy and symptom free.

As conclusion, from our research that had been done, we totally agreed that the roommate

is having a kidney failure. So, we strongly suggest her to take immediate treatment so that her

illness can be cure and hopefully she will get well soon.

SELF REFLECTION

Marlisa binti Sau (D20101037418)

From this PBL, I could learn and got more information about our kidneys and urinary

system. Firstly, I faced many obstacles, such as not understanding a few concepts, but as time

progressed, I learnt about these problems and could understand step by step with the help of

lecturer and friends. In addition, I learnt how to identify the main objective of problem given,

solved all the problem, making a mind map, interpreted data and made reasonable conclusion.

From the point, I started to find and gain more information from internet, notes, books, articles

and journals. This PBL also, teach me how to think creatively using scientific method to get the

solution of the PBL. Finally, I got many input about urinary system in our body such as how

kidneys function and how the waste product are secreted from body.

Nur Hayati binti Yusoff (D20101037419)

After following the PBL session, there is a positive change in the way I learned. Because,

through the PBL session, we learnt how to synthesis the idea, how to generate the idea and how

to find the solution for the problem given. To achieve all this, we have to work in a group and

know how to cooperate to each other. Here, I learnt to accepts others opinion and give full

commitment to my group members. So that, each of us will help each other to complete the task

given and get benefit from the PBL session. This can help me in a future because when I be a

teacher, I also have to work with people. Through PBL, I have more confident on this because I

already experienced it. Besides,I also got extra knowledge while doing the research to solves

problems given. For example, before this, I never knew about B.U.N (Blood Urea Nitrogen) test.

After try hard to solve the problems given, I have several information in mind about B.U.N.

B.U.N test is actually test to measures the amount of nitrogen in blood that comes from the waste

product. From this, we know whether the kidney function normally or not. So, the PBL actually

help increase the student’s skill in learning.

Norfarrahdilah binti Amir (D20101037438)

I have learned many things from the PBL session. In this PBL, we are given a situation to

be solved using a scientific method. For this PBL situation, we must solve our roommate

problem where she is having some symptoms of serious health decline. To solve this problem,

we work in a group of four. All of us have our own opinions, different idea and different way of

thinking. So, working in a group teaches me how to be patient and be understanding about

different idea that been suggest by the members of our group. To give full commitment, I learned

to accept my friend’s opinion and give my own opinion so that we can decide which idea is

better to fulfill this task. I’m happy with the commitment that been show by all of my group

members and we can work and tolerate with each other very well. All this really help me in my

future where I need to work with other people. Other than that, through this PBL, I gain new

knowledge where we find the additional information from many source to solve this case. To me,

PBL sessions really help me in the way I learn.

Siti Salwa binti Abdullah (D20101037439)

Being in such a group that is very understanding and always happy make me free of

pressure finishing all the tasks given to our group. Being working together as a team, I found

myself able to give full commitment in every single activity in the problem – based learning

sessions. Besides, I also now have a better view about the excretory system in Physiology subject

and also the PBL’s techniques and this encourages me to learn and find even more information

about this excretory system functioned in our body. Other than that, the PBL’s technique teaches

me the correct way in understanding and studying Physiology. I can use this technique to teach

my students when I become a teacher in future. For me, working in a group need me to be more

understanding and respect other opinions or problems. Comes from different backgrounds

however make me even easier to adapt and work together with my group members. This is all

because of our good cooperation among each other. From group’s view, I can see that my group

can work together and give our best for each task given by the lecturers. Through meetings and

the discussions that we conducted, each of us trying very hard to be punctual and give ideas as

much as we can in order to make our works success and approved by the lecturers. Besides,

through the discussions also we now have a better and clearer understanding about Physiology

and the topic, excretory system specially. Our group members that came from Chemistry’s

background also now able to give their opinions or ideas based on the tasks. This shows that, by

having lots of discussions make us easier to understand the subject and we trying to keep on

having discussion for our final exam that just around the corner.