Urinary System(A&P)

Question 1

Urinary-Excretory System(Function)

Answer 1

• excretion of wastes(nitrogenous waste=protein metabolism)
• fluid and electrolyte balance
• acid base balance(ph balance)
• normal range: 4.8-6(acidic)
• regulation of Bp
• aldosterone: cause kidney to reabsorb sodium; water allows kidney to get rid of potassium
• posterior pituitary: ADH all kidney to get rid of water
• stimulated erythropoiesis
• kidney activates vitamin D in fortified milk, helps calcium absorption

Question 2

Organs of the urinary system

Answer 2

1) Kidney
2) Ureters
3) Urinary Bladder
4) Urethra

Question 3

Kidney(Location)

Answer 3

• retropentoneal in the upper portion of the abdominal cavity at about the level of T12/L1
• r. kidney is usually lower than the L kidney

Question 4

Kidney(Description)

Answer 4

• reddish brown bean shaped organs
• 4inch long, 2inch wide, 1inch thick
• medial structure has an indentation called the hilus which is the point at which blood vessels enter and exit from the kidney. it also has a point where the uterers exit the kidney
• covered with renal capsule(fibrous membrane) embedded in adipose tissue and the renal fascia which also anchors the kidney to the peritoneum and the abdominal wall

Question 5

Renal Cortex:

Kidney internal structure

Answer 5

-outer layer made up of renal corpuscles and convoluted tubules

Question 6

Renal Medulla:

Kidney internal structure

Answer 6

• inner layer of tissure made up of Loop of henle and collecting tubules
• tubules form cone shaped structures called renal pyramids
• the tips(apex/papilla) of the renal pyramid points toward the renal the renal pelvis

Question 7

Renal Pelvis

Answer 7

• funnel shaped cavity that forms the upper part of the ureter
• collects urine made by the kidney and directs it towards the ureter
• edges of the renal pelvis are cup/funnel shapes called calyces.
• urine flows from the renal pyramid to the calyces to the renal pelvis to the ureter

Question 8

Blood Supply

Answer 8

• kidney is perfused by the renal artery
• kidney recieves 20-25% of cardiac output
• in the kidney the renal artery branches into a number of arteries which branch into a number of arterioles
• arterioles came in contact with the nephrons
• venules in the kidney unite to form veins
• veins in the kidney merge to form the renal vein which leaves the kidney and joins the inferior vena cava

Question 9

Nephron(Microscopic structures)

Answer 9

• structural and functional unit of the kidney
• each kidney contains about 1 million nephrons
• each nephron makes urine

Question 10

nephron

Answer 10

made up of two parts

1) tubular structure(a tube w/ capsule at one end)
2) vascular structure(network of blood vessels
- function of the nephrons depends on the way in which the tubular component and the vascular component are arranged in relationship to each other

Question 11

Filtration(Function of nephron)

Answer 11

-movement of water and solutes from the glomerulus to bowmen’s(glomerular capsule)

Question 12

Secretion(Function of nephron)

Answer 12

-additional waste products and unneeded electrolytes are moved from the bloodstream into the forming urine

Question 13

reabsorption(function of nephron)

Answer 13

-water,electrolytes, and additional needed materials are moved from the forming urine into the bloodstream.

Question 14

Renal Corpuscle

Answer 14

2 parts

• glomerulus=vascular/capillary
• glomerular(bowmans) capsul=tubular

Question 15

glomerulus(renal corpuscle)

Answer 15

• cluster of capillaries
• afferent-arteriole brings blood to the renal corpuscle and branch into large number of capillaries; the afferent arteriole has a wider diameter which takes blood away from the renal corpuscle
• capillaries merge to form the efferent arteriole which take blood away from the renal corpuscle

Question 16

bowmans/glomerular capsule(renal corpuscle)

Answer 16

• part of the tubular structure
• surrounds the glomerulus and receives the filtrate
• renal corpuscle is the site of filtration

Question 17

renal tubules

Answer 17

-long tubular structure that is surrounded by the peritublar capillaries
-renal tubules are the site for:
SECRETION: waste products and unneeded electrolytes are moved from the bloodstream into the forming urine
REABSORPTION: water, electrolytes and additional needed materials are moved from the forming urine into the bloodstream

Question 18

proximal convoluted tubule

Answer 18

• first part of renal tubules after the glomerular capsule
• site of most reabsorption
• normally 100% of the filtered glucose, amino acids and other useful metabolizes are absorbed

Question 19

loop of henle

Answer 19

• hair pin, u shaped structure
• has a descending limb and an ascending limb
• reabsorption of K,NA,Cl and the beginning of H20 reabsorption occurs in the loop of henle

Question 20

distal concoluted tubule

Answer 20

• extension of the ascending limb of the loop of henle
• reabsorption of NACL and h2o continues
• DCT is the site for the action of aldosterone
• DCT is the site of tubular secretion
• site of most secretion

Question 21

collecting tubule

Answer 21

• formed by the union of the dct from seceral nephrons

- collecting tubules empty into the calyces of the renal pelvis

Question 22

physiology of urine production

Answer 22

• urine is formed as water and solutes
• more btw the vascular and the tubular structure of the nephron
• urine formation involves 3 process:
• glomerular formation
• tubular reabsorption
• tubular secretion

Question 23

glomerular filtration

Answer 23

• occur b/c the pressure in the glomerulus is higher than the pressure in the glomerular capsule
• recall that afferent arteriole is wider in diameter than the efferent arteriole
• glomerular filtration is dependent on Bp
• glomerular filtration involves movement of water and solutes from the bloodstream into the bowmans capsule
• what passes into the filtrate is dependent on the size of the pores of the filter
• normally electrolytes,urea,creatine,and glucose pass easily into the filtrate
• normally rbc and large proteins do not pass into the filtrate
• glomerular filtration depends on Bp and the amount of blood that reaches the kidneys
• normal urine production is 1-2Liters a day

Question 24

glomerular filtration is

Answer 24

125ML/min or 180L/day

• normal urine production is 1-2Liters a day
• approx. 99% of the filtrate gets reabsorbed

Question 25

Tubular reabsorption

Answer 25

- as filtrate passes through the tubules water and other useful substances move from the tubules to the peritubular capillaries(99% of the filtrate is reabsorbed) - most tubular reabsorption takes place in the proximal convoluted tubule(PCT) - the kidneys regulate both the substances and the quantity of these substances that gets reabsorbed

Question 26

reabsorption takes place by

Answer 26

- diffusion: movement of solute from high to low concentration - active transport: movement of solute from low to high(need atp and pump)(against diffusion gradient) - osmosis: diffusion of water from high to low across semipermeable membrane(from dilute solution to concentrated solution) - na is reabsorped by active transport - cl by diffusion - water by osmosis follows the sodium - na is the single most important electrolyte that is involved in fluid balance and fluid distribution in the body - all of the glucose in the filtrate gets reabsorbed by active transport - all the amino acids and small proteins in the filtrate get reabsorbed by active transport - PTH promotes the reabsorption of calcium(PTH dissolves bone) - waste do not get reabsorbed comes back by osmosis - for many of the substances that are reabsorped by the renal tubules there is a threshold level limit for reabsorption

Question 27

Tubular secretion

Answer 27

- actively moves material from the blood stream to the tubules - H+(ph balance), K+, ammonium ion, urea, uric acid, creatine, drugs and metabolites

Question 28

concentration of urine volume

Answer 28

-additional fluid balance and bp regulation -concentration of urine depends on: Osmosis ADH secreted by the posterior pituitary Aldosterone(secreted by the cortex of the adrenal gland) ADH makes