Lecture 9: Urinary System

Question 1

Kidney general function

Answer 1

FILTER plasma constituents from blood, then selectively REABSORB water and useful constituents from filtrate, then EXCRETE the excess

Question 2

kidney location

Answer 2

dorsal part of abdominal, on each side of aorta and vena cava, ventral to lumbar vertebrae
-in cows the LEFT kidney is pushed to the middle by the stomachs

Question 3

Renal hilus

Answer 3

concave depression of kidney, where blood vessels and nerves enter ureter and lymphatics leave

Question 4

Renal pelvis

Answer 4

expanded origin of the ureter within the kidney

• receives urine from the collecting tubules of the kidney
• not all species have a pelvis

Question 5

Major calyces

Answer 5

openings from medulla to renal pelvis

Question 6

Medulla

Answer 6

portion surrounding the renal pelvis

• striated appearance due to radially collection of tubules that form the renal pyramids
• medulla contains the loop of henle

Question 7

Cortex

Answer 7

located on top of the medulla

• granular appearance due to many renal corpuscles/nephrons
• proximal and distal convoluted tubules are located in cortex

Question 8

How much of total blood supply goes to kidneys?

Answer 8

about 1/4

Question 9

Blood vessels supplying kidneys: arteries and afferet arterioles

Answer 9

two renal arteries enter the hilus and divide into a number of large branches, the arcuate arteries, and afferent arterioles, each of which branch to form capillary networks called GLOMERULUS

Question 10

Arteriae rectae

Answer 10

capillary network surrounding the nephron, collecting tubules, and loop of henle

Question 11

Efferent arterioles

Answer 11

-efferent arteriole leaves the glomerulus and forms the capillary network surrounding the nephron called ARTERIAE RECTAE

Question 12

arcuate vessels

Answer 12

artery and vein that border the cortex and medulla

Question 13

Nephron

Answer 13

functional part of the kidney

-includes the glomerulus, glomerular (Bowman’s) capsule, proximal and distal convoluted tubules

Question 14

artery path:

Answer 14

interlobar arteries-arcuate arteries-interlobular arteries-afferent arterioles

Question 15

Venous drainage pathway

Answer 15

venae rectae-arcuate veins-interlobar veins, and renal vein

lymph drains from kidney to the renal lymph nodes

Question 16

Renal plexus

Answer 16

supply of sympathetic nerves connected to kidney

• follows blood vessels and terminate mainly at glomerular arterioles
• Vagus nerve may also supply

Question 17

ureters

Answer 17

muscular tube that carries urine from the pelvis of kidney to the bladder

Question 18

urinary bladder

Answer 18

hollow, muscular organ that varies in size depending on amount of urine
-as the bladder fills the walls become thinner, and most of the bladder is displaced up cranially toward the abdominal cavity, as it rests on the floor of the pelvis

Question 19

bladder has a sphincter to…

Answer 19

control passage of urine into urethra at the neck of the bladder

Question 20

pelvis, ureter, bladder, and urethra are all lined with what?

Answer 20

transitional epithelium

Question 21

Micturition

Answer 21

expulsion of urine from the bladder

• a reflexive activity stimulated by distention/stretching of bladder
• voluntary control of the external sphincter around the neck of the bladder can prevent emptying reflex

Question 22

Functions of the kidney

Answer 22

• excretion of waste products
• maintenance of homeostasis: the condition of internal environment including water balance, pH, osmotic pressure, electrolyte levels, and concentration of many plasma substances

Question 23

glomerulus

Answer 23

network of capillaries (a tuft) at the beginning of the nephron, where filtration occurs

Question 24

Glomerular capsule

Answer 24

the blind end of the tubule that surrounds the glomerulus

-visceral layer surrounds the capillaries, while the parietal layer is continuous with the proximal con. tube.

Question 25

renal (malphighian) corpuscle, filtration part of nephron

Answer 25

part of the nephron. the complex of the glomerulus and the glomerular capsule

• where filtration of fluid from blood occurs
• approx. 100 times as much fluid passes through this filter as is eventually excreted
• blood pressure must be kept high to filter that quickly, which is ensured by capillaries being closer to an artery than a vein

Question 26

Both arterioles control glomerular have smooth muscle in order to

Answer 26

control glomerular pressure

Question 27

juxtaglomerular cells

Answer 27

present in afferent arterioles approaching glomerulus

• surrounded by a cuff of myoepithelial cells (act like both smooth muscle and epithelium)
• sites of RENIN production

Question 28

myoepithelial cells

Answer 28

act like smooth muscle and epithelium

-surround the juxtaglomerular cells, which are the site of renin production

Question 29

Stimulus of renin production

Answer 29

• fall in blood pressure in afferent arteriole
• decrease in plasma sodium concentration
• decrease in distal tubular osmolarity
• stimulation of sympathetic nerve fibers supplying afferent arterioles

Question 30

Function of renin

Answer 30

-acts on globulin-angiotensinogen to produce angiotensin

Question 31

angiotensin

Answer 31

• acts as a vasoconstrictor to increase blood pressure

- acts on adrenal gland to secrete ALDOSTERONE, which causes kidney to conserve sodium

Question 32

aldosterone

Answer 32

increases sodium uptake from distal convoluted tuble and increased water uptake to increase blood pressure