kidneys (9a)

Question 1

functions of the urinary system

Answer 1

collect water and filter body fluids
concentrate and eliminate waste (nitrogenous waste, toxins, drugs, excess ions) from body fluids
maintain blood pressure
stimulate red blood cell production

Question 2

anatomy of the urinary system

Answer 2

renal artery, renal hilum, renal vein, kidney, ureter, urinary bladder and urethra

Question 3

characteristics and function of the ureters

Answer 3

carry urine from renal hilum to bladder using peristalsis (smooth muscle)
also have valves to prevent backflow of urine

Question 4

characteristics and function of the urinary bladder

Answer 4

made of 3 layers of smooth muscle called the detrusor muscle
walls are folded (rugae like stomach) when empty
mucosa is made of transitional epithelium
located behind the pubic symphysis
stores urine

Question 5

characteristics and function of the urethra

Answer 5

carries urine from bladder to exterior by peristalsis (and semen in men)
urine release is controlled by
external urethral sphincter (skeletal muscle)
internal urethral sphincter (smooth muscle)

Question 6

micturition mechanism

Answer 6

voiding (emptying) reflex
stretch receptors fire -> parasympathetic neurons fire and activate detrusor muscle (motor neurons controlling external sphincter stop firing) -> smooth muscle contracts and internal sphincter is pulled open -> urine flows and the feeling of needing to pee is felt -> external sphincter is opened when you want
sympathetic nervous system keeps internal sphincter closed

Question 7

characteristics of the kidneys

Answer 7

are outside of the peritoneal cavity, protected by bottom ribs, right kidney is lower

Question 8

what are the structures outside of the kidneys and what do they do

Answer 8

renal hilum: indentation where ureters, vessels and nerves enter/exit
fibrous capsule: encloses each kidney
perirenal fat capsule: cushions
renal fascia: anchors kidneys to surrounding structure

Question 9

what are the three regions of the kidney

Answer 9

renal cortex
renal medulla
renal pelvis

Question 10

characteristics of the renal cortex

Answer 10

outermost
contains the major portions of nephrons

Question 11

characteristics of the renal medulla

Answer 11

has renal pyramids (have parts of nephrons) and renal columns (contain blood vessels)

Question 12

characteristics of renal pelvis

Answer 12

innermost
papilla of pyramids project into minor calyx which becomes the major calyx which ultimately drains into ureter

Question 13

what are the components of blood flow in kidneys

Answer 13

aorta -> renal artery -> afferent arteriole -> glomerulus (capillaries) -> efferent arterioles -> peritubular capillaries -> renal vein -> inferior vena cana

Question 14

characteristics of the nephron

Answer 14

made of epithelial cells
structural and functional units of kidney for urine production
two types: cortical nephron (more abundant) and juxtamedullary nephron

Question 15

difference between nephron types

Answer 15

juxtamedullary nephrons have their loops in the renal medulla while most cortical nephrons’ loops stay in the renal cortex
juxtamedullary nephrons regulate water balance because their long loops allow for a strong osmotic gradient to be created

Question 16

structure of nephrons

Answer 16

renal corpuscle: has bowman’s/glomerular capsule and glomerular capillaries
renal tubule: has proximal convoluted tubule (PCT), nephron loop (loop of henle) and distal convoluted tubule (DCT)

Question 17

anatomy and function of the renal corpuscle

Answer 17

circle around glomerulus (capillaries)
capillaries are surrounded by specialized cells (podocytes) that form the inner layer of the capsule (the circle)
podocytes cling to the capillaries and act as filtration slits which prevents blood cells and most proteins from passing
all plasma components and solute pass and form the filtrate
the outer layer of the capsule is made of epithelial cells and contains the filtrate in the capsule space

Question 18

anatomy of the renal tubule

Answer 18

capsule opens into the PCT and leads to loop (has descending and ascending limb) which leads to DCT

Question 19

which capillary beds are present at the nephron and where are they

Answer 19

glomerulus (inside capsule)
peritubular capillary bed (wrapped around renal tubule

Question 20

characteristics of glomerulus

Answer 20

fed by the afferent arteriole and drained by efferent arteriole
filters blood
the high pressure forces the fluid and solutes out of blood and into the capsule

Question 21

what doesnt get filtered in glomerulus

Answer 21

RBC, WBC and plasma proteins

Question 22

characteristics of the peritubular capillary beds

Answer 22

fed by efferent arteriole and drains into the interlobar veins
adapted for absorption and clings close to the renal tubule
low pressure

Question 23

mechanism of the nephron

Answer 23

arterial pressure forces water and solutes from blood into capsule
filtrate goes from PCT to loop to DCT to collecting duct
fluids and solutes are returned to the peritubular capillary beds
collecting duct receives urine and go into the medulla

Question 24

what are the steps of urine production

Answer 24

glomerular filtration
tubular reabsorption
tubular secretion

Question 25

what happens during glomerular filtration

Answer 25

process of passing blood through a filter to move fluid and solute into the capsule water, glucose, amino acids and nitrogenous waste make up the filtrate (plasma proteins and blood cells stay to prevent all the water from passing through to maintain osmotic pressure)

Question 26

what happens during tubular reabsorption

Answer 26

transport of substances from renal tubule back into the blood reabsorption begins as soon as the filtrate enters the PCT (most occurs in the PCT) in healthy kidneys all organic nutrients (glucose and amino acid) are completely reabsorbed, the normal plasma concentrations are restored by the kidney most solutes are reabsorbed by active transport

Question 27

what happens during tubular secretion

Answer 27

when the capillary secretes substances into the tubule majority of the secretion occurs in the PCT secretion is important to control blood pH (acidic blood = more H+ is secreted) H+, K+, urea, creatinine and certain organic acids are secreted back into the renal tubule

Question 28

what does urine contain compared to filtrate

Answer 28

filtrate: has everything from plasma minus the proteins urine: filtrate - water, nutrients and essential ions (mostly metabolic waster and unneeded substances)

Question 29

what is urea

Answer 29

product of amino acid breakdown

Question 30

what is uric acid

Answer 30

product of nucleic acid metabolism

Question 31

what is creatinine

Answer 31

metabolite of creatine phosphate which stores energy for the regeneration of ATP and is found in skeletal muscle tissue

Question 32

what should the urine not have

Answer 32

glucose blood proteins RBC WBC hemoglobin bile