KIDNEY (8) Flashcards
- What is the optimal pH of the body?
a. Around 7.4
- What happens if the body pH gets too far away from 7.4?
a. enzymes stop working and normal physiological process breakdown
- How can the body overcome the problem of getting too far away from the optimal pH?
a. The body has buffering system
- Howe can the body maintain buffering system and manage the products of that buffering?
that requires both the kidney and the lungs working properly
- Where is the kidney in the body and how does it look like?
a. Kidneys are paired structures that are located At the back of the peritoneal cavity
- How is the kidney supplied and how much does it take from the cardiac output?
a. Kidneys are being supplied by the renal arteries which receive blood from the aorta
b. It takes about 25% of the cardiac output
- What happens if the kidney becomes diseased?
a. Kidneys would have reduced blood flow and that leads to kidneys not working quite as well
- How much blood do the kidneys filter per/day?
a. 1500 L per/day
- How is the blood supply to the kidneys maintained
a. by reducing blood flow to other areas.
- What happens if someone is in shock?
a. they will get pail clammy extremities because their peripheral resistance is increasing to keep as much blood pressure as possible in your central vessels in your aorta and renal arteries
b. therefore, the kidneys carry on being perfused with blood that contains oxygen, nutrients (skin, peripheral muscles can go for few hours without having too much blood)
- list the functions of kidneys:
a. Filter 1500 L of blood per/day
b. Fluid balance
c. Acid-base balance
d. Na balance
e. Excretion including active excretion of toxins and some drugs
f. involved in endocrine control of:
i. Ca and bones metabolism
ii. Hb (haemoglobin)
- In which part of organ does blood filtration occur?
a. In glomerulus
- What is the working unit of the kidney?
a. Nephron
- Describe the blood filtration pathway:
a. Blood from aorta comes to the renal artery in the kidney.
b. Renal artery divides into smaller arterioles until it gets to the smallest arterioles that feed the blood vessels in the glomerulus.
c. Glomerulus filters small molecules and water where the blood keeps bigger molecules (e.g. proteins)
d. Large molecules remain in blood, pass into vasa recta.
e. Whereas, high volume of fluid leaving the glomerulus, going to the proximal convoluted tubule.
f. Then the liquid passes through the proximal convoluted tubule into the descending limb of Henle. Then back up to the ascending limb of Henle
g. From the ascending loop of Henle, the urine then goes to the distal convoluted tubule and then to the collecting duct
- Limb of Henle: perform as a countercurrent multiplier and that is where the osmatic gradient is generated that allows the volume of water and the concentration of salt in the urine to be decided and adjusted.
- Describe how Countercurrent multiplier works in the loop of Henle?
a. Descending loop is permeable to water and as we’ve got very dilute liquid in this tube therefore, water diffuses passively out of that
b. Fluid in LoH becomes more hypertonic.
c. Ascending LoH, wall permeable to Na and Cl but not water and as we’ve got concentrated fluid coming up the loop, sodium, and chloride can diffuse passively out down the concentration gradient into the blood.
d. Fluid becomes more concentrated.
e. Water and salt reabsorbed into the blood
- What is the function of the Loop of Henle?
a. Generate the osmatic gradient that allow the other processes go on
- What are the 4 groups of activities that we have in the kidney?
a. Passive reabsorption
b. Passive secretion
c. Active secretion
d. Active reabsorption
- Explain what passive reabsorption/ secretion is and give 1 example for each:
- Passive reabsorption: is reabsorption passively down an osmotic gradient.
- Example: the water in the descending LoH
- Passive secretion – is secretion passively down a concentration gradient.
- Example: NH4/ ammonium is passively secreted from cells into urine.
- How is ammonium secreted by the cells of LoH lining wall?
a. The cells of the lining of the LoH are metabolically active and they will produce metabolites including ammonium
b. Ammonium is secreted from the cells passively down the concentration gradient
- Explain what active reabsorption/ secretion is and give examples for each:
a. energy dependent process that actively pushes molecules either through the cell or out of the cell
Active secretion
* Drugs (penicillin)
* H+ and hydrogen ions
Active reabsorption
* Glucose
* Lactate
- Where does the final concentration of urine occur? And how is that process controlled
a. It occurs in the collecting duct
b. This process is controlled by Antidiuretic Hormone (ADH) which is secreted by the pituitary gland. In the pituitary gland the cells can sense blood pressure and blood osmolarity. The pituitary gland produces ADH when the blood pressure is Low and the osmolarity is high therefore, the ADH-dependent reabsorption in the collecting duct will stimulate reabsorption of water and that will lead to:
i. Increased water reabsorption
ii. Decreased urine output
iii. Increased blood volume which maintain the circulating blood volume
- Differentiate between diabetes mellitus and diabetes insipidus:
- diabetes mellitus – sugar diabetes that is related to insulin, secretion of insulin, resistance to insulin, management of sugar levels in the blood. If this was untreated, or undiagnosed diabetes you get high thirst drive, and very high urine output
- diabetes insipidus – In this case you get very a lot of very dilute urine that doesn’t necessarily contains any sugar in it. It is caused usually by tumors or injury to the pituitary and that means the patient cannot secret ADH and therefore, ADH-dependent water reabsorption in the collecting duct doesn’t happen resulting in up passing a lot of very dilute urine as the body cannot concentrate its urine
- what is Renin-Angiotensin System? And how does it work?
a. This is group of cells that is called Juxta-glomerular apparatus (JGA).
b. It is a point of contact of glomerulus and distal tubule/collecting duct.
c. The cells there can senses reduction in blood pressure, urine concentration.
d. If they sense drop in the Bp or increase in the urine concentration, then they will release Renin hormone
e. Renin catalyses conversion of angiotensinogen (from liver) to angiotensin 1
f. ACE catalyses conversion of angiotensin 1 to angiotensin 2. Leads to vasoconstriction increased BP
g. angiotensin 2 act on the adrenal gland and stimulates the secretion of the aldosterone increased water and Na retention.
h. Therefore, produce concentrated urine maintain BP
- What are the Signs/symptoms of kidney dysfunction
- change in urine output
- Dark urine
- Proteinuria
- Haematuria
- Na/K imbalance
- Fluid retention
o Oedema
o Hypertension
- What problems might arise if you had Proteinuria due to kidney dysfunction?
a. Losing proteins –> can interfere with your metabolic status –> could have problems with e.g., healing, weight-loss
b. Losing proteins –> also can interfere with the balance of extracellular and intracellular fluid
- Why could people with kidney dysfunction have oedema?
a. Due to fluid retention so, people could might have Low urine volume fluid retention fluids tend to set where gravity puts it (tends to pool closes to the floor) Oedema in your ankles (puffy Oedema)
- What is pitting oedema? And what does it associate with?
a. is where you press on the tissues for few seconds and take your thumb away, the indentation of your thumb will stay there which is a sign for fluid retention).
b. Usually associated with heart failure, but also can be associated with kidney failure
- What could be a consequence of problems with fluid balance/ fluid retention?
a. hypertension
- what could patient get in Acute Kidney Injury?
a. Decrease in urine output
b. Decrease in secretory function
c. Impaired Na/K balance
- What can cause AKI?
There are many causes including:
a. Pre-renal: dehydration,
Low blood pressure low fluid volume heart not pumping very well cannot maintain pressure in the kidneys kidneys are going to be perfused acute kidney disease
low BP, heart failure, myocardial event or lost lots of blood due to trauma
b. Intra-renal:
inflammation, embolism, scarring/damage to nephron
inflammation: Lots of inflammatory products in the blood these products going to be clubbed in the filter/ or you get complement deposit in the filter
Embolism: if you get clot. If it goes down into the aorta or into the renal artery, it can then embolise in your kidney and stop that kidney being perfused). These can cause scaring and damaging to the nephron
c. Post-renal: obstruction, stones
If the flow of urine from the kidney into the ureters is blocked by stones or cancer or scaring from previous surgery etc.. obstruction of that whatever gets there dammed up in the kidney kidney filter will not be able to work and stop working
