Lecture 1-intro

Question 1

Functions of the kidney

Answer 1

Regulation of volume and composition of extracellular fluid, acid-base balance, arterial blood pressure regulation, elimination of metabolic waste products, regulation of erythrocyte production, gluconeogenesis, elimination of foreign chemicals, communication (pheromones)

Question 2

Functional subunit of the kidney

Answer 2

Nephron

Question 3

Gross anatomy of the kidney

Answer 3

Medulla is on the inside, cortex is on the outside, pyramids in the medulla, papilla where the urine enters the minor calyx

Question 4

Bowman’s capsule

Answer 4

Where filtration occurs
Always located in the cortex
Surrounds glomerular capillary bed

Question 5

Three capillary beds of the kidney

Answer 5

Glomerular capillary bed (filtration)
Peritubular capillary bed (reabsorption and secretion)
Vasa recta (loop of Henle)

Question 6

Blood supply of a nephron

Answer 6

Renal artery -> interlobar artery -> arcuate artery -> cortical radiate artery -> afferent arteriole -> glomerular capillary bed -> efferent arteriole -> peritubular capillary bed ->cortical radiate vein -> arcuate vein -> interlobar vein -> renal vein

Question 7

Collecting ducts

Answer 7

Many nephrons enter into one duct

Empties urine into the renal pelvis

Question 8

Overall organization of renal system

Answer 8

Arterial plasma enters glomerular capillary bed -> filtration into Bowman’s capsule -> filtrate moves into proximal tubule -> loop of Henle -> distal tubule -> collecting duct (major site of ADH)

Question 9

Juxtaglomerular apparatus

Answer 9

Formed when the thick ascending loop of Henle loops around to touch the glomerular capillaries

Has macula densa

Question 10

Macula densa cells

Answer 10

Cells in the juxtaglomerular apparatus that stain dark and help regulate sodium by controlling blood flow through glomerulus

“Self-feedback loop”

Question 11

Relationship between osmolality and position in nephron

Answer 11

Cortex has same osmolality as plasma… osmolality increases as you get into the medulla;

Thick medulla is an adaption used in desert animals

Question 12

Types of nephrons

Answer 12

Long loops of henle- better at concentrating urine; 100% of cat nephrons

Short loops of Henle

Question 13

Bird renal function

Answer 13

Excrete uric acid (needs less water to be excreted) rather than urea
Have a mixture of nephrons with loops of Henle (mammalian-like) and nephrons without loops of henle (reptilian like)
Can move urine from cloaca into the colon for more reasborption (post-renal modification
Have salt glands
GFR is regulated by how many nephrons are filtering

Question 14

Reptile renal function

Answer 14

Nephrons have no loops of henle
Excrete uric acid
Have salt glands
GFR is determined by number of nephrons filtering
Thick integument prevents water escape

Question 15

Amphibian renal function

Answer 15

No loops of henle
Regulate GFR with number of nephrons filtering
Excrete uric acid
NO salt glands

Question 16

Mammalian renal function

Answer 16

Loops of henle
GFR is regulated by net filtration pressure
Excrete urea not uric acid
NO salt glands

Question 17

Differences between salt glands and mammalian kidneys

Answer 17

Salt glands- work only in response to need, increase in size with a chronic salt load, NaCl concentration is constant, outflow consists entirely of NaCl

Mammalian kidneys- works continuously, no change in size with salt load, NaCl concentration varies, consists of other ions other than salt water