Module 6 Flashcards
list the 4 functions of the urinary system
- regulates
- excretes waste
- endocrine functions
- produces
functions of the urinary system - regulation
- food volume
- solutes + electrolytes
- acid base balance
functions of the urinary system - excretes waste
- metabolic eg nitrogenous waste
- foreign eg drugs
functions of the urinary system - endocrine functions
- erythropoietin (stimulates RBC production)
- renin (enzyme)
functions of the urinary system - produces
- active vitamin d
- glucose
what structures supply the kidneys with blood ?
- renal arteries
- branches of abdominal aorta
list the 3 regions of the kidney
- cortex
- renal medulla
- renal pelvis
Cortex
- outer region
- contains cortical nephrons
Renal Medulla
- cone shaped tissue
- renal pyramids
Renal Pelvis
- funnel shaped
- continuous with ureter
- drains papillae through minor + major calyces
what is a nephron
the functional unit of the kidney
- forms urine
are the collecting ducts a part of the nephron
no
what are the 4 compartments of a nephron
- renal corpuscle
- renal tubule
- juxtamedullary nephrons
- cortical nephrons
how is blood supplied to the nephron
blood enters the glomerulus via the afferent arteriole + exits via efferent arteriole
what are the 3 processes of urine production
- Glomerular Filtration
- Tubular Reabsorption
- Tubular Secretion
Urine Production - Glomerular Filtration
A non selective process in which blood pressure forces fluid through glomerular membrane
what is the filtration membrane of the glomerulus composed of and what molecules are allowed to pass ?
- made up of perforated epithelium + thin epithelial cells
and a collagenous membrane - allows free passage of water + most solutes into glomerular capsule (other than blood cells, proteins and negatively charged proteins)
What is the Glomerular Filtration Rate
total volume of filtrate per minute
does an increased Glomerular Filtration Rate lead to an increase or a decrease in urine production
increased urine production
how is glomerular filtration regulated
via myogenic mechanism
Glomerular Filtration Regulation - Describe the function of the myogenic mechanism
The changes in systemic BP causes either constriction or dilation of the AFFERENT arteriole
Urine Production - Tubular Reabsorption
A selective process that reclaims most of the filtrate formed during glomerular filtration
Tubular Reabsorption - what is the site of most reabsorption
PCT (65% of NA+ and water reabsorbed here)
Tubular Reabsorption - role of nephron loop
- water leaves descending loop
- no solute reabsorption in descending loop
- absorbs water + solutes in ascending portion of loop
Tubular Reabsorption - role of DCT - CD
- involvement of hormones
- ADH = diuresis
- Aldosterone = cells absorb more NA+
Urine Production - Tubular Secretion
A selective process moving substances from blood into filtrate
Urine Production - Tubular Secretion - Where does it mostly occur, and what happens ?
- occurs in PCT
- eliminates excess K+
- controls blood pH
- disposal of substances eg drugs
what is the pH of urine
pH 6 ( variable 4.5 - 8)
describe the chemical composition of urine
- 95% water
- 5% solutes
- nitrogenous waste
- urea
define urine
the stuff removed from the body after filtration, reabsorption and secretion by renal tubule
Pathway of urine
- papillae of pyramids
- Minor Calyces
- Major Calyces
- Pelvis
- Ureter
- Bladder
define micturition
voiding
presence of glucose in urine
diabetes mellitus
presence of protein in urine
exercise, pregnancy, hypertension, renal disease
presence of ketone bodies in urine
- starvation
- uncontrolled diabetes mellitus
presence of bile in urine
- liver disease
- obstruction of bile ducts
presence of RBC’s in urine
- trauma
- kidney stones
- infection
- cancer
presence of WBC’s in urine
infection
what are the 2 main fluid compartments in the body
- intracellular fluid
2. extracellular fluid
what is the major cation and major anion of extracellular fluid
cation: NA+
anion: Cl
what is the major cation and major anion of intracellular fluid
cation: K+
anion: Hpo43 -
what is hypertonic movement
water moves from ICF to ECF
what is hypotonic movement
water moves from ECF to ICF
when is the hypothalamic thirst centre activated
- by a 1-2% change in osmolarity
- or a 5-10% drop in plasma volume
what inhibits thirst
- moistening of mucosa
- stretch receptors
what occurs with the hormone aldosterone in the ECF
- release of angiotenisn II when potassium levels are high
- reabsorbs NA+ and water
what occurs in the ECF with the activation of the renin angiotensin system
- releases ADH, aldosterone
- thirst mechanism stimulated
what is the direct regulation of BP
change in BP + alter in urine outpt
what does aldosterone regulate
regulates electrolyte concentration in extracellular fluid (NA+,K)
- therefore increases Bv + BP
when is ADH released
- solute concentration increases
- angiotensisn II
what are the 4 things Angiotensin II regulates within the renin angiotensin mechanism
- ADH
- Aldosterone
- Hypothalamic Thirst Centre
- Peripheral Vasoconstriction
define dehydration
when water output exceeds input
water depletion exceeds NA+ depletion
early signs of dehydration
- thirst
- flushed skin
- decreased urine output
term for prolonged dehydration
hypovolaemia
prolonged signs of dehydration
- decreased circulating blood volume
- confusion/ disorientation
- hypovolemic shock
what hormonal systems are activated by a decrease in BP + BV
- renin angiotensin system
- aldosterone
- ADH
define hypotonic hydration
when eater intake exceeds water output
signs of hypotonic hydration
- nausea
- vomiting
- muscle cramps
Hypotonic Hydration - Cerebral Oedema
- disorientation
- coma
- death
Hypotonic Hydration - Hyponatremia
- low NA in ECF
- cells swell
Blood pH - acidiosis
pH below 7.35
Bloog pH - alkalosis
pH above 7.45
what are the 3 main mechanisms to regulate blood pH
- chemical buffer systems
- respiratory regulation
- renal mechanisms
list the 3 chemical buffer systems used to regulate blood pH
- bicarbonate buffer system
- phosphate buffer system
- protein buffer system
list the 2 renal mechanisms used to regulate blood pH
- conserve + generate HCO3
2. excrete HCO3 in collecting ducts
describe the bicarbonate buffer system
- carbonic acid
- bicarbonate (wake base)
- if there is a low ph, tie up H+ = increase in Ph
vice versa - removed and retained via respiratory and renal mechanisms
describe metabolic acidioisis/alkalosis
disturbances causing excess acids or bases
describe respiratory acidiosis/ alkalosis
- fails to regulate
- hypoventilation
- retention of co2
- pH < 6.8 = coma, death
