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List the major organs of the urinary system

Kidneys (2): process blood and form urine.
Ureters (2): Tube running from each kidney to urinary bladder.
Urinary bladder: reservoir for urine before leaves body - expels urine.


State and describe 5 functions of the kidneys other than urine formation

Blood plasma filtration - the kindeyys act as a blood filter to identify and excrete toxic waste products.
2. Regulation of blood volume - by conserving H2o or elimination H2o.
3. Regulation of body fluid osmolarity: regulate salt in plasma (Na+, K+, Ca2+, Cl-)
4. Regulation of blood pressure: kidney secrete renin which ↑ bp by activating renin-angiotension-aldosterone pathway.
5. Produces erythropoietin: production of RBC
6. Production of calcitriol (vit D): helps in absorption of calcium from GIT, regulating calcium homeostasis.
7. Regulate blood pH ; kidneys excrete H+, maintains balance of body fluids
8. Gluconeogenesis: kidneys can use amino acid glutamine to synthesis new glucose,


Name the major nitrogenous wastes and state their sources

1. Urea - Protein catabolisim → amino acids → -NH2 removed and converted by the liver → urea. Urea is most abundant nitrogenous waste.
2. Uric acid: nucleic acid catabolisim
3. Creatinine: creatine phosphate catabolisim


Describe the location and gross anatomy of the kidneys

Kidneys lie against posterior abdominal wall at level of T12 to L3. Retroperitoneal (located behind the peritonum) along with ureters, urinary bladder, renal artery and vein w adrenal glands. Right kidney is slight lower due to the large lobe of right liver.

Size of fist, roughly oval. Has a slit for nerves, blood vessels, lympathics.

Internal structure:
Renal cortex: outter tissue
Renal medulla: inner tissue
Renal colums: between medullary pyramind (comlums)
Calyx: urine collecting region


Trace the flow of blood through the kidneys & identify the vessels

Renal artery: brings blood into each kidney
Interlobular arteries: extending towards the cortex


Describe the nephron and its 2 parts (renal corpuscle and renal tubule)

The nephron is the functional unit of the kidney, responsible for urine formation. Made up of two regions (renal corpuscle and tubule) connects to a shared collecting duct.

Afferent arterioles enters glomercular capillary network.
Efferent arteriole leaves glomerulus and extends to the peritubular blood supply. Then Vasa Recta capillary network surrounding Henleys loops required for urine formation.

The renal corpuscle:
Rental Tube: PCT is the first part of the renal tubule; segment nearest to the Bowmans capsule


Describe the filtration membrane and the process by which the kidney filters the blood plasma

Filtration is the first step in blood processing. Occurs in the renal corpuscles as a result of a pressure gradient. Glomerular filtration rate (GFR) determined mainly by glomerular hydrostatic pressure and therefore directly related ti systemic bp.
Filtration membrane: three barriers through which fluids pass.
1. Fenesrated endothelium of glomerular capillaries: are highly permeable, excludes RBC from filmtration.
2. Basement membrane: small protein bound solutes don't pass - charge.
3, Filtration slits of podocyte:


Explain the forces/factors that promote and oppose filtration

MORE INFO Filtration pressure: GFR
Promote: Rental artery ↑ volume of blood


Describe how renal autoregulation controls glomerular filtration rate

MORE INFO Myogenic mechansim: based on the tendency of smooth muscle
Tubuloglomerular mechanism: involved Juxtaglomerular apparatus: volume and concerntration of filtrate analysed by Marcula densa cells at the distal tubule → signsals to Juxtaglomerular cells to regulate blood flow.


Describe how the nervous system controls glomerular filtration rate

SNS control of GFR strenous exercise/constriction can stimulate afferent arterioles to constrict. This leads to ↓ GFR and urine production redirecting blood flow to heart, brain


Describe tubular reabsorption and how it takes place

Reclaiming water and solutes from the filtrate and returning them to the blood.
Tubular reabsorption: Na+ transported into blood. Glucose: passively transported. Chloride



Describe tubular secretion and state solutes that are excreted

The movement of substance out of the blood into tubular fluid. Secrete potassium and amonium. Waste removal: waste products. Acid-base balance.


Describe how the nephron regulates water conservation

The Nephron Loop (Loop of Henley). It generates salinity gradient, allows the collecting duct to concerntrate urine.


Discuss the roles of aldosterone, atrial natriuretic hormone (ANH) and parathyroid hormone (PTH) on kidney function

Aldosterone: secreted by adrenal cortex ↑ distal tubule absorption of sodium, ↑ Na+ in blood. ↑ Na+ reasborption and collecting duct in Na+ channels
PTH: Secreted by parathyroid for in response to calcium deficiency. ↑ phosphate content and ↓ calcium in urine


Explain how the collecting duct and antidiuretic hormone (ADH) regulate the volume and concentration of urine

MORE INFO Dependant on hydration. Drinking large amounts of water will produce large volume of hypostatic urine


Describe the anatomy of the ureters, urinary bladder, and urethra.

Ureters: COmposed of 3 layers; mucous lining, muscular middle and fibrous outter.
Urinary bladder: transitional epithelium 3 layers also,


Explain how the nervous system controls the voiding of urine

Voiding Urine (Micturition) 200ml of urine in the bladder activates stretch receptors to sacral spinal cord.
Allows urine to pass out.

Micturin Reflex


Name the major fluid compartments & explain how water moves from one to another

Intracellular fluid (ICF) - fluid contained within cells. (chemical reactions that maintian life). Movement: Osmosis & hydrostatic pressure.
Extracellular fluid (ECF) the fluid environment in which cells live fluid outside the cells. (tissue, blood, synovial fluid). Movement: Osmosis, sodium, potassium.
Differences between the two is ↑ concerntration of protein (albumin).

If total water is too low, fluid moves out of the cells into plasma.


List the body’s sources of water and routes of water loss

Intake and water loss balanced. This ensures electrolytes are maintained, as imbalances can be fatal.
Water gain: performed water, ingested in food and drink.
Metabolic water: a by product of aerobic metabolism and dehydration synthesis.
Water loss: urine, faeces, expired breath, sweat, cutaneous transpiration. Respiratory loss ↑: with cold, dry air or heavy work.
Perspiration loss ↑: with hot, humid air or heavy work.
Insensible water loss: breath
Obligatory water loss: breath, sweat, faeces, urine.


Describe the mechanisms of regulating water intake and output

AntiDureticHormone: ↑ water retention and thirst. (↑ BP)
Aldosterone: ↑ Na+ and water retention, (↑ BP)
AtrialNatriureticPeptide - ↓ decreases Na+ (and water retention. (↓ water retention) (↓ BP).
Urine volume dictates hydration/dehydration. Two factors can determine this"
Glomerular filtration rate (GFR)
Rate of tubular reabsorption (ADH and aldosterone secreted).

Systems: RAAS reduced water volume leads to reduced plasma volume and hypotension.


State some conditions where there is a fluid deficiency or a fluid excess amongst fluid compartments

Fluid LOSS
Volume depletion (hypovolemia): total body water ↓, osmolarity normal. Hemorrhage, severe burns, chronic vomiting for diarrhoea.
Dehydration: total body water ↓, osmolarity rises. Caused by lack of drinking water, diabetes, profuse sweating.

FLUID RETENTION: Volume excess: both Na+ and water retained, ECF isotonic ↑ BP
Hypotonic hydration: more water than Na+ retained ECF hypotonic = cellular swelling.

FLUID SEQUESTRATION: oedema, hematomas, pleural effusions, ascites


State the physiological roles of sodium and potassium

Sodium (Na+) cation (- charge) of ECF 90-95%
important for nerve functioning.
Potassium: most abundant
cation of ICF, greatest determinant of intracellular osmolarity. important for nerve functioning and heart functioning.

Na+ concerntrated outside ECF.
K+ concerntrated inside cell (ICF).

Na+ & K+ pump


State the term for an excess or deficiency of sodium and describe consequences of these imbalances

HypONAtraemia = ↓ Na+ in blood. Headache, confusion, stupor, seizures and coma. Exercise
HypErNAtrEmia = ↑Na+ in blood. Thirst, confusion, neuromuscular excitability, seizures, coma
HypoKalaemia - ↓ K+ in blood, muscle weakness, loss o fmuscle tone, cardiac arrthymias.
HyperKalaemia ↑ K+ in blood; blood loss


Describe the hormonal and renal mechanisms that regulate the concentrations of sodium and potassium

Aldosterone: salt retaining hormone.
ADH ↑ blood Na+ levels stimulates ADH release, (kidneys absorb more water)
ANP from stretched atria - kidneys excrete more Na+ and H20, ↓ BP.


Define and write chemical equations for the bicarbonate, phosphate, and protein buffer systems

The most omportant buffer system in the ECF

Co2 + H20 →← H2CO3 →← H+ + HCO3-
Carbon dioxide plus water, transfer over a H+ if needed, water plus carbon = carbonic acid plus H+ then turns into bicarbonate HCO3.
Phosphate buffer system: H2PO4- →←HPO42-+ H+


Name 4 disorders of acid-base balance and state possible causes of these disorders

1. Respiratory acidosis: results from hypoventilation. When rate of alveolar ventilation fails to keep pace with the bodys rate of CO2 production. Headache, shortness of breath and lethargy.
2. Respiratory alkalosis: results from hyperventilation. CO2 eliminated faster than produced, pH ↑.
3. Metabolic acidosis: increased production of organic acids such as actic acid and ketone bodies. Caused by alcoholisim, diabetes, starvation, kidney failure, ingestion of aspirin. pH ↓
4. Metabolic alkalosis: Overuse of bicarbonates, loss of stomach acid via chronic vomiting. Symptoms include nausea, tremors and numbness


Explain how the respiratory and urinary systems compensates acidosis and alkalosis, and compare their effectiveness and limitations.

Respiratory compensation changes in pulmonary ventilation to correct changes in pH of body fluids by expelling or retaining CO2.
Hypercapnia (excess CO2) stimulates pulmonary ventilation eliminating CO2 allowing pH to rise.
Hypocapnia (deficiency of CO 2) ↓ ventilation and allows CO2 to accumulate lowering pH.

Renal compensation - an adjustment of pH by changes the rate of H+ secretion by the renal tubules.Slow but better at restoring a fully normal pH