L14*-Physiology of the renal system I-general intro to RENAL

Question 1

What maintains the water-body balance in the body?

Answer 1

Urine is under the greatest independent control of the water-body balance. Other variables can be temperature, metabolic rate and diet.

Question 2

Define plasma

Answer 2

The fluid component of the blood, and
usually represents about 55% of the blood by volume.

The rest of the volume is occupied by cells

Question 3

What are the separations in the tube after a whole blood sample is centrifuged ?

Answer 3

Plasma
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platelets
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leucocytes
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erythrocytes

Question 4

Define Volume of distribution and the equation to calculate it.

Answer 4

Definition :- The volume of fluid required to contain the total amount of drug in the body at the same concentration as that present in the plasma.
Vd = Q / Cp
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Q = amount of drug
Cp = plasma concentration of drug

Question 5

Define Osmotic pressure

Answer 5

-At the interface between 2 solution, molecules exchange because of diffusion.
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-If the concentration of any species is different on either side of the interface, there will be a NET movement of molecules from one side the membrane to the other.
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-In the case of water, the force (per unit area) required to oppose such a new movement is called osmotic pressure.

In biological tissues the interface between solution is at a semi-permeable membrane, usually the plasma membrane.

Question 6

Give me an example showing the importance of osmotic pressure changes in the body. and name the 4 types of oedema from this cause.

Answer 6

-Fall in plasma [albumin]
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-Causes : liver failure, protein malnutrition, renal failure.
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-effects : oedema such as >
peripheral oedema
pulmonary oedema
ascites(abdominal) > 2o to liver failure(cirrhosis)
cerebral oedema

Question 7

Name 4 roles of the Kidney

Answer 7

-elimination of endogenous and exogenous compounds
-maintenance of chemical homeostasis, like pH.
-maintenance of volume status.
-endocrine signalling

Question 8

Name 3 roles of the lower urinary tract

Answer 8

-storage of urine
-urination at a socially appropriate time and place
-maintenance of continence > ability between the bladder and the urethral sphincters to control the urination voluntarily.

Question 9

Name the renal interaction with the gastrointestinal system.

Answer 9

-Gut regulates the input and the kidney regulates the output and equilibrium between these 2 systems.
-GIT is the source for rapid water, K+,H+ or HCO3-loss.Sometimes the gut absorbs excessive amounts of these. Like drinking too much water can lead to water poisoning. The kidneys filter excessive or deficient substances in the bloodstream and returns equilibrium.
-Hepatic failure through hypoalbuminemia causes large changes in renal fluid handling.

Question 10

Name the renal interaction with CV system.

Answer 10

-Maintains blood pressure through regulation of volume and hence filling pressure.
-Regulating the tight ionic composition required for appropriate cardiac 💪 function.
-Regulating volume required for vascular filling : adaption to hypovolemic shock.
- A role in hypertension > high b.p

Question 11

Name the renal interaction with Respiratory system.

Answer 11

-Regulating pH : metabolic and respiratory acidosis /alkalosis
-Joint metabolic pathways for the regulation of renin/angiotensin system

Question 12

Name the renal interaction with endocrine.

Answer 12

-Through the renin-angiotensin system, regulates the secretion of aldosterone from the adrenal cortex, hence renal Na+, K+ and water regulation.
-Vitamin D regulation > regulates Ca2+
-This link is the target of central hormonal control by vasopressin (ADH)
- Diabetes : main target organ is Kidney. most commonest cause of end stage renal failure.

Question 13

Name the renal interaction with ANS

Answer 13

• Kidneys receive afferent innervation(sensory nerve fibres which sends signals from the kidney to CNS) and efferent nerves(motor nerve fibres which transmit signals from CNS to kidney) controlling blood flow in the kidney.

-this interaction allows new clinical therapies for hypertension, particular renal denervation.

-Autonomic innervation of the bladder and urethra are essential for controlling the storage of urine and micturition.

Question 14

Name the renal interaction with Haematology

Answer 14

-Through erythropoietin, the kidneys regulate the production of erythrocytes.
-Many hematological malignancies (particularly
myelomas and leukaemias) lead to renal disease, through the deposition of antibodies.

Question 15

Name the renal interaction with Musculoskeletal system

Answer 15

-Response to crush injury > adapting to high K+ and myoglobin
-Pelvic floor > maintenance of continence in women.
- Skeletal 💪s controls the external urethral sphincters