Urinary System

Question 1

Function

Answer 1

Renal blood and lymph vessels ureter nd nerves another and leave via helium and concave middle border of kidney
Urine formed in kidney passes through openings in renal papilla into drainage systems the begin at minor calcyx
Minor merge into major
Wall of cal yes and e=renal pelvis lined with transitional epithelium and contains smooth muscle
Peristalsis propels urine through calyces renal pelvis and ureter to bladder

Question 2

Blood flow through the nephron

Answer 2

Afferent arterioles enters the woman’s capsule then subdivide into glomerulus
Blood leaves efferent arterioles
Afferent = bigger diameter
- increased blood pressure inside glomerular capillaries and drives filtration through walls into glomerular capsule.
- fluid has left the blood and entered capsule now called filtrate

Question 3

Blood flow around nephron

Answer 3

Allows exchange of substances between filtrate and bloodstream
Efferent arterioles - remove waste products and supplies tissue with o2 and nutrients
Wall f glomerulus capsule is single layer of fat and highly permeable epithelial cels
Facilitate diffusion

Question 4

Bladder layers

Answer 4

Other - contains loose connective tissue
Middle - interlacing smooth muscle and elastic fibres
Inner - mucosa

Question 5

Balder what happens when fills and empties

Answer 5

Whe it empties inner layer is folded gradually disappears when it fills
When filling distension causes awareness of need to wee

Question 6

Formation of urin stages

Answer 6

Filtration
Selective re absorption
Secretion

Question 7

Filtration

Answer 7

Through semi permeable will of glomerlar capillaries and capsule
Only water and small molecules through
Occurs when the is a different in glomerulus and the pressure in the filtrate in bowman capsule
Efferent arterioles narrower so hydrostatic pressure build up in glomerulus capsule and pressure opposed by osmotic pressure of blood provided by plasma proteins

Question 8

Selective re absorption

Answer 8

Most reabsrption from filtrate back to blood ids in the pct as has microvilli
Substances that are re absorbed are water electrolytes and nutrients and amino acids and glucose
Only 60-70% of filtrate reaches loop of Henle
Only 15-20% f original filtrate reaches Distal convoluted tubule

Question 9

Secretion

Answer 9

Filtration occur as blood passes throught glomerulus
Some not entirely filterd out due to size or hurt time spent in the glomerulus
Some are cleared from the blood into filtrate by secretion from peritubular capillaries in convoluted tubules
Tubular secretion of h+ is important in in maintaining blood pH

Question 10

Constituents of urine

Answer 10

Water 92%
Urea 2%
-these make up 2%-
Create
Urin acid
Ammonia
Sodium
Potassium
Chloride
Phosphates
Sulphate
Oxidates

Question 11

Hormones that effect selective reasborptio

Answer 11

Parathyroid
Antidiuretic
atrialnatrieutic peptide

Question 12

Parathyroid

Answer 12

Regulate absorption of calcium and phosphate to maintain normal blood levels

Question 13

Antidiuretic

Answer 13

Secreted by posterior pituitary gland
Increases permeability of DCTand collecting ducts to water

Question 14

Atrialnatriuetic peptide

Answer 14

Sereted by atrua in response to stretching of atrial wall whe blood volume is increased
Reduce re absorption of na and h2o by DCT and collleting dct
Lowers blood volume and reduces atrial stretching as more na and h2o excreted
ANP secretion turned off.

Question 15

Auto regulation

Answer 15

Renal blood flow and glomerular filtration protected by auto regulation maintained at constant pressure across wide range of systolic blood pressure 80-120mmHg
GFR depends on glomerular blood pressure so the pressure is controlled independently of systemic blood pressure which fluctuates with activates with activities
Renal flow controlled locally
- strenuous exercise when blood pressure is increased
- auto regulation constricts efferent arterioles to protect capillaries and enable kidney to maintain blood flow through glomeruli

Question 16

Active re absorption

Answer 16

Active transport at carrier sites in epithelial membrane
Na and Cl absorb by active and passive mechanisms depending on site of nephron
Glucose and amino acids don’t normally appear in urine
Normal blood glucose is 3.5-8mmol/L
If above 9 it appears in urine as all carrier sites in nephron walls are occupied and mechanisms for active transport out of tubules is overloaded

Question 17

Renin angiotensinogen mechanism

Answer 17

Cells in Afferent arterioles release renin in response to sympathetic smlation and low blood volume.
Renin converts angiotensinogen to angiotensinogen 1
Angiotensinogen converting enzyme converts angiotensinogen 1 into 2- a vasoconstrictor = high blood pressure
Angiotensin 2 raised blood potassium levels also stimulate adrenal gland secrete aldosterone which stimulates na and h2o re absorption in kidney increases blood volume and pressure.

Question 18

Water balance and urine output

Answer 18

Kidney control balance between fluid intake and output
Minimum output 500ml a Amy
Urine volume in excess o this is controlled by ADH
When osmotic pressure is raised, ADH output is increased
Water is reabsorbed by DCT and collecting ducts is increase reducing blood osmotic pressure and ADH output
Negative feedback maintain pressure within normal lines

Question 19

What is micturition

Answer 19

Accumulatin of urine in bladder cgi ages receptors in bladder wall
Generates sensory Afferent) impulses transmitted to spinal cord
Mictuition reflx initiated
Stimulates involuntary contraction of detrusor muscle and relaxation of internal urethral sphincter - expels urine form bladder