Urinary

which organ is mahogany brown, bean shaped, paired and situated in the retroperitoneal space near the posterior abdominal wall

Kidney

what is the general structure of the kidney

Capsule
cortex
medulla
renal crest or calyx

which structure of the kidney is dark brown and granular

Cortex

which structure of the kidney is discrete, pyramid shaped, and has pale striated regions

Medulla

what species has multilobar shaped kidneys

Cattle

which species has unilobar shaped kidneys

cats, dogs, small ruminants, pigs, horses

which species have unipyramidal kidneys

cats, dogs, small ruminants, horses

which species have multipyramidal kidneys

pigs and cattle

what is the kidneys function (the three F's)

Filtration
fluid regulation
functional endocrine organ

the kidney filters blood based on

molecular weight, shape, and charge

what is removed by filtration

waste products

what is recovered during filtration

useful metabolites

during filtration what is stored

fluid waste (urine)

what is being regulated in the kidney during fluid regulation

Fluid volume
Acid/base balance
Electrolyte composition

the kidney regulates fluid volume through

renin

what does renin do

regulates blood volume/ pressure though:
reabsorption of sodium though aldosterone which is released from the adrenal (it regulates aldosterone as well)
causes vasoconstriction through activation of angiotensin II

what is happening during acid/base balance

secreation or conservation of acids and bases (achieved through HC03- and H+)

the kidney acts as a functional endocrine organ producing what three things

Renin
Erythropoietin
Vitamin D metabolites

what does erythropoietin do

Acts on bone marrow to generate new erythrocytes

how does the kidney produce vitamin D metabolites

converts vitamin D to dihydroxycholecalciferol which regulates calcium transport

what is the basic functional unit of the kidney

Nephron

what are the three main components of the nephron

renal corpusle
tubular component
collecting duct system

what makes up the renal corpuscle

glomerulus
bowman's capsule

what are the tubular components of the nephron

proximal convoluted and straight tubule
thin descending and ascending parts of the loop of henle
distal straight and convoluted tubule

name the arteries and arterioles found in the kidney

Renal artery
Interlobar arteries
Arcuate arteries
Interlobular arteries (radial)
Afferent glomerular arterioles
efferent glomerular arterioles

what are the two types of nephrons

Cortical
Juxtamedullary

follow a drop of blood going out of the cortical nephrons

Efferent glomerular arteriole, pertubular capillary network, stellate veins, interlobular veins, Arcuate veins, interlobar vein, renal vein

Follow a drop of blood going out of the juxtamedullary nephron

efferent glomerular arteriole, vasa recta, arcuate veins, interlobar vein, renal vein

what are the parts of the glomerulus

tuft of capillaries (fenestrated endothelium)
intraglomerular mesangial cells (for support)
Afferent glomerular arteriole supply's blood
Efferent glomerular arteriole drains blood

what surrounds the glomerulus and is part of the renal corpuscle

bowman's capsule

what are the layers of bowman's capsule

Visceral layer
bowman's space
parietal layer

what is the visceral layer composed of

Podocytes/ epithelium

what are podocytes

highly modified simple squamous epithelium to allow for filtration

what does a substance have to go through in order to be filtered

Fenestration (pore) of glomerular endothelial cell
Basal lamina of glomerulus
slit membrane between pedicels

the fenestration (pore) of glomerular endothelial cell prevents filtration of what and what does it allow

prevents blood cells but allows all components of blood plasma to pass through

the basal lamina of glomerulus prevents

filtration of larger proteins

what is difference between the basal lamina of the glomerulus and other basal lamina

it is three times thicker

the slit membrane between pedicels prevents filtration of

medium-sized proteins

what is on top of the slit membrane

podocytes

which tubule is the longest, widest and most well developed segment of the nephron

Proximal tubule

where is the proximal tubule mostly confined

the renal cortex

tubular/convoluted portions of the proximal tubule are located in the

pars convoluta

straight portions of the proximal tubule are located in

pars radiata

the proximal tubule reabsords approximately 75% of what

sodium and chloride ions and water of the ultrafiltrate

the proximal tubule reabsorbs 100% of what

glucose, amino acids, and proteins of the ultrafiltrate

what dose the proximal tubule excrete

organic solutes, drugs, and toxins

explain the microanatomy of the proximal tubule

lined by simple cuboidal epithelial cells
sits on a well defined basement membrane
well developed brush border
Nuclei are located basally

true or false
Juxtamedullary nephrons have a shorter LOH than cortical nephrons

False.
Juxtamedullary nephrons have a much longer LOH than cortical nephrons

which tubule has thin descending and ascending limb

Loop of henle

what are the two functions of the loop of henle

to generate high osmotic pressure in extracellular fluid of the medulla (counter-current multiplier system)
Reabsorption of water back into circulation via vasa recta (counter-current exchange system)

how can you distinguish the difference between LOH and capillaries

LOH has large lumen with more nuclei protruding into it than cappillaries
LOHs squamous epithelium cells are slightly thicker them endothelial cells of vessels
Nuclei stain less densely
lumina contain no erythrocytes

tubular portions of the distal tubule are located in

pars convoluta

Straight portions of the distal tubule are located in

pars radiata

the main purpose of the distal convoluted tubule is

that it is responsible for reabsorption of sodium by an active process controlled by aldosterone release from the adrenal

the DST absorbs

sodium and chloride ions

what is the distal tubule impermeable to and what can freely pass in and out

impermeable to water and urea
ions can enter and leave

the DCT controls acidity of ultrafiltrate by

active secretion of hydrogen ions into the lumen

microanatomy of the distal tubule

lined by low cuboidal cells
more nuclei evident in tubular cross section
nuclei are more centrally/apically located

what is the ratio of cross-sections of PCT to DCT

usually 7:1

what is the macula densa

specialized portion of the distal convoluted tubule
monitors filtrate volume and sodium concentration
instructs JG cells to release renin of necessary

true or false
the collecting duct system is not considered to be a part of the nephron

true
this is because of it's different embroyological origin.

the collecting duct system is comprised of what three things

collecting tubule
collecting ducts
duct of bellini (Papillary duct)

what opens into the area cribosa to drain urine into the minor calyx/renal pelvis

the papillary duct (duct of bellini)

the collecting duct system is impermeable to what

water (unless exposed to ADH) and a portion of the duct is permeable to urea

microanatomy of the collecting tubule

cuboidal epithelium (stain poorly)
Intercalated cells
high number of mitochondria and microvilous surface
help control acid/base balance by transport of hydrogen ions

micro anatomy of the collecting duct

Columnar epithelium
intercalated cells (less numerous in collecting ducts

microanatomy of the ducts of bellini

(also known as papillary ducts)
columnar epithelium
no intercalated cells

parts of the juxtaglomerluar (JG) apparatus

Macula densa of the distal tubule
Juxtaglomerular cells of the afferent glomerular arteriole
Extraglomerular(EG) mesangial cells (aka polkissen or lacis cells)

macula densa microanatomy

Appers as a dense spot due to tall closely packed simple columnar epithelial cells

what is the function of the macula densa

this is not known, though to have sensory function with JG cells

functions of the JG Apparatus include

functions of the JG cells and EG mesangial cells

what are JG cells and what is their function

Modified smooth muscle cells
these grandular cells secrete the proteolytic enzyme renin

where are the EG mesangial cells found

occupies the space borders by the affernt and effernt arteriole, macula densa, and the vascular pole of the renal corpusle. it is contiguous with intraglomerular mesangial cells

what is the function of EG mesangial cells

the precise function is not understood

what is the main purpose for ureters, urinary bladder, urethra

conduit for and storage of urine waste

the ureters and urinary bladder are lined by what epithelium

transitional epithelium

the urethra is lined by what type of epithelium

transitional epithelium near bladder gradually turning into stratified squamous non-keratinizing along the remainder of it's length

the ureters propel urine from the

kidneys to the urinary bladder

true or false
the ureters have an additional smooth muscle layer at its distal 3/4.

False
it dose have an additional smooth muscle layer at its distal 1/3

the urinary bladder is

hollow, muscular (detrusor), Distensible (elastic) and has an internal and external sphincter (these are at the junction between the urinary bladder and urethra)

is the urethra shorter in males or females

females

what is the urethra utilized for in females

urination

what is the urethra utilized for in the male

urination and ejaculation

what is are the layers of the lower urinary track

mucosa
lamina propria/submucosa
tunica muscularis
tunica Adventitia/serosa

the mucosa layer, in the lower urinary track, is composed of what type of epithelium

transitional epithelium

the urogenital system goes through three phases on its way to becoming fully functional kidneys. what are these stages

Pronephros
Mesonephros,
Metanephros (definitive kidney)

the pronephros development begins

early in the fourth week

in the pronephros the mesenchymal cell aggregates

in the neck region of the embryo, this is nonfunctional as a kidney but soon transforms into a ligament

The pronephros attaches to

pronephric ducts, then the cell aggregates of pronephros degenerate

the promesonephric ducts are used in the next stage of kidney development, they end in the

cloacal region caudal to the mesenchymal cell aggregates of the pronephros

mesonephros are

large and elongated, functional interim kidneys producing urine which is released into amniotic fluid. they lie caudal to pronephros

mesonephros begins development

late in fourth week

mesonephros consist of

glomeruli and mesonephric tubules which open into mesonephric duct, a continuation of the pronephric duct

mesonephric duct opens in to

the cloaca

true or false
the mesonephros proper degenerates but tubules and ducts have derivatives in adult males

true
the tubules form ductuli efferent and ducts form a number of reproductive structures like the mesonephric duct becomes the wolfian duct in the male

metanephros begin there development in

early fifth week

metanephros is the \_______ kidney

permanent

the metanephros develops from the

ureteric bud and the metanephric mesenchyme

the metanephros is functional at

nine weeks

the urine produced by the meanephros is released into

the amniotic fluid