Urinary System Flashcards
List FOUR functions of the urinary system.
(1) Excretion
Waste - uric acid, creatinine, urea
Ions - na, k, h
Toxins
(2) Balance
Balance in terms of what to retain and what to get rid of. Specific examples are
- balance of PH levels in body fluids, especially blood
- glucose
- electrolytes/ water balance
(3) Production of hormones – Erythropoietin and Calcitriol
(4) Regulation of blood pressure, volume and osmolarity (concentration)
Name three types of waste products excreted by the kidney
(1) Metabolic wastes which include Urea, Uric Acid and Creatinine
(2) Ions such as H+
(3) Toxins which include those ingested, absorbed, inhaled, medications, deactivated hormones.
Name THREE metabolic wastes containing nitrogen excreted by the urinary system.
Urea
Uric Acid
Creatinine
Name ONE ion excreted by the urinary system.
Hydrogen
This is particularly important to prevent excess acidity
State the minimum daily quantity of urine (ml) required to clear body waste.
500 ml
Name THREE electrolytes regulated by the kidneys
Sodium
Potassium
Hydrogen
Chloride
Bicarbonate
Magnesium (I think)
Describe specifically how the kidney plays a role in blood pH balance
- The kidney excretes Hydrogen into urine.
- They also produce the buffer bicarbonate (HCO3) to neutralise acidity
Describe the main role of the following hormones in relation to the kidney:
a. Calcitriol
b. Erythropoietin
a. Calcitriol
- active form of Vit D
- Stimulates calcium and magnesium uptake from the GIT. These are key minerals needed for bone strength and muscle contraction and release.
- Reduces calcium loss from the kidneys so that blood calcium levels go up.
b. Erythropoietin
- It triggers red bone marrow to manufacture red blood cells. (Erythropoiesis
Explain why anaemia is common in renal failure
In renal failure, erythropoietin production is inadequate leading to a lack of production of red blood cells and resulting in anaemia
Also losing blood cells through glomerula damage
State the normal renal threshold for glucose in mmol / L.
Normal range 4-7 mmol
The renal threshold is 9 mmol/L, after which it is excreted
Describe specifically how the kidney compensates for ‘low blood glucose’
The kidneys are able to make glucose by converting the amino acid glutamine to help elevate blood sugar levels when they are low. It is called gluconeogenesis.
Glutamine is highly circulating in our blood.
Explain why the right kidney is lower that the left kidney.
The liver occupies considerable space on the right side
With regards to renal anatomy of the following tissue layers, describe where they are located and what their functions is.
Tissue Layers
1. Renal Capsule
2. Adipose Capsule
3. Renal Fascia
Tissue layer name: Renal Capsule
Tissue layer location: Deep layer
Tissue layer function: Connective tissue; maintains kidney shape
Tissue layer name: Adipose Capsule
Tissue layer location: Middle layer
Tissue layer function: Fatty tissue layer; Protection and support
Tissue layer name: Renal Fascia
Tissue layer location: Superficial layer
Tissue layer function: Connective tissue; anchors the kidney
The kidney is divided into two distinct regions. What are they?
The renal cortex,
and the renal medulla.
The renal cortex houses the renal corpuscle and convoluted tubules
The renal medulla houses the renal pyramids and loop of Henle.
Explain what is meant by the ‘hilum’.
It is the point of entry and exit to the kidneys for blood vessels, lymph vessels, nerves and ureters
State the % cardiac output received by the kidney.
20-25% of cardiac output goes through the kidneys
Name the location into which urine drains from the nephrons
The minor and major calyces
State which of the following components are in the ‘renal tubule’ or ‘renal corpuscle’:
a. Loop of Henle
b. Distal convoluted tubule
c. Proximal convoluted tubule
d. Bowman’s capsule
e. Glomerulus
a. Loop of Henle –Renal Tubule
b. Distal convoluted tubule – Renal Tubule
c. Proximal convoluted tubule – Renal Tubule
d. Bowman’s capsule – Renal Corpuscle
e. Glomerulus – Renal Corpuscle
Draw and label the ‘nephron’:
Name the specific location in a nephron where anti-diuretic hormone acts
The distal convoluted tubule in order to reabsorb water
Which part of the nephron reabsorbs the most water?
Proximal Convoluted Tubule
Explain how urine is transported from the renal pelvis to the urinary bladder.
It is transported through two ureters, each 25-30 cm long. Peristaltic contractions, the pressure of the urine and gravity move the urine along.
Describe the three layers of the ureters and their role.
Inner mucous membrane - contains transitional epithelium which is able to stretch and goblet cells to secrete mucus
Muscularis – Middle layer of smooth muscle fibres produce peristaltic contractions to move urine through the ureter.
Adventitia – Outer coat of connective tissue containing blood and lymph vessels and nerves of the ‘muscularis’ in the ureter.
*NOTE: The urinary bladder has a very similar 3 layers but the smooth muscle in the muscularis layer is called Detrusor muscle
State the volume of urine (ml) which when exceeded triggers a desire to urinate.
200 ml
Name the small triangular area located on the posterior floor of the bladder.
Trigone - It is a flat section at the bottom of the bladder that is bordered by the two ureteral openings and the urethral opening.
Name the specific location of the ‘detrusor muscle’
Muscularis layer of the bladder
It is used to create the internal urethral sphincter.
Explain the difference between the ‘internal urethral’ and ‘external urethral’ sphincters in the urethra.
The internal urethral sphincter is made of smooth muscle and is involuntary.
The external urethral sphincter is voluntary
List TWO differences between the female and male urethras.
- Length: 4 cm verses 20 cm for women verses men as for me it needs to go through the penis.
- Male urethra passes through the prostrate
Name THREE processes involved in urine formation
- Glomerular Filtration
- Tubular Reabsorption
- Tubular Secretion
Describe specifically how the glomerulus is adapted for filtration.
- It has a large surface area for filtration.
- It is very leaky, 50 x more than normal capillaries, which allows substances to be pushed through easily
- Efferent arteriole is much narrower than the afferent arteriole which means that substances get in more easily than they get out allowing more time in the glomerulus for filtration.
Name FOUR blood constituents that pass into glomerular filtrate.
- Amino acids
- Electrolytes (mineral salts)
- Glucose
- Hormones
- Toxins
- Waste products – urea; uric acid; creatinine
- Water
Name TWO blood constituents that remain in glomerular capillaries.
Plasma Proteins
Blood cells – red, white and platelets
Define glomerular filtration rate (GFR). Why do we use it?
The amount of filtrate formed in the renal corpuscles of both kidneys each minute.
It is a measure of kidney disease. Anything affecting the Glomerular Filtration process will affect the GFR.
State how GFR is measured.
Through a blood test
State the normal adult GFR range
- should be > than 90.
- Typically it is higher in men at 125ml/min and for women 105 ml/min
- 15ml/min suggests kidney failure
What does GFR stand for?
Global filtration rate
Through what intervention is GFR measured?
Blood test
Describe specifically how ‘colloid osmotic pressure’ develops
Colloid Osmotic Pressure is a pressure exerted by proteins, most notably albumin.
Albumin helps to retain water by attracting it.
Albumin should not pass through the glomerulus. When it does it is excreted with urine and you will see a frothy urine.
Less albumin in the blood lowers osmotic pressure and this means that the blood is less able to retain water. This leads to accumulation of interstitial fluid causing oedema.