CH. 25 - urinary system

Where does gluconeogenesis occur in the body?

kidneys

The kidneys secrete what two substances responsible for bodily endocrine functions?

renin

EPO/erythropoietin

What is the function of renin?

bp regulation

What is the function of erythropoietin?

regulates RBC production

What are the 4 urinary structures superior → inferior?

kidneys → ureters → bladder → urethra

The kidneys are __________lly located, being between the body’s dorsal wall + this layer

retroperitoneal

The ____ kidney is lower in the abdominal cavity due to presence of the ____

right

liver

What functionally unrelated gland(s) lie atop each kidney?

adrenal

What is the innermost, fibrous connective tissue layer encasing the outer surface of each kidney?

renal capsule/fascia

What 3 structures pass through the indentation of the renal hilum?

renal artery

renal vein

renal pelvis/ureter

Superficial region/tissue of a kidney anatomy?

renal cortex

Inner region of kidney housing the pyramids?

renal medulla

Identify A?

renal cortex

Identify B?

renal medulla

Identify C?

fibrous capsule

Identify D?

minor calyx

Identify E?

major calyx

Identify F?

renal column

Identify G?

renal pyramid

Identify H?

ureter

Identify I?

renal pelvis

Identify J?

papilla of renal pyramid

What is the order in which renal pyramids drain?

papilla → minor calyx → major calyx → renal pelvis → ureters

Branching from the aorta, what structure brings blood into the kidney via the hilum?

renal artery

Branching from the IVC, what structure takes blood away from the kidney via the hilum?

renal vein

What blood vessel leads into glomerulus?

afferent arteriole

What blood vessel leads away from/out of the glomerulus?

efferent arteriole

Trace the pathway of blood flow from the aorta through the renal blood vessels to the IVC

aorta → renal artery → afferent arteriole → glomerulus → efferent arteriole → peritubular capillaries → renal vein → IVC

structural + functional units of kidneys that form urine

nephron

What substance do the nephrons work to create?

urine

Where in the nephron is filtrate made?

glomerulus

The glomerular capillaries are ________, making them highly porous

fenestrated

What cells does the glomerulus contain, specialized for the regulation of what can exit + enter?

podocytes

What cup-shaped structure surrounds the glomerulus?

Bowmans capsule

The _____ arteriole is wider/thicker than the _____ arteriole

afferent

efferent

The class of a nephron is determined by what?

location within the kidney

The majority of nephrons are what class?

Cortical

Class of nephrons located majority in the cortex, with only certain sections of tubule entering medulla?

cortical

Class of nephrons that produce concentrated urine & have long nephron loops with thin + thick segments?

juxtamedullary

Nephron capillary bed specialized for filtration, drained + fed by both afferent and efferent arterioles

glomerulus

The peritubular capillaries + vasa recta both originate from what blood vessel?

efferent arteriole

What capillary beds are used by the cortical nephrons?

peritubular

What capillary beds are used by the juxtamedullary nephrons?

vasa recta

The juxtaglomerular complex of the nephron is a region where the __________ of the tubule lies against the ______ arteriole

ascending limb

afferent

What two things is the juxtaglomerular complex of the nephron responsible for the regulation of?

blood pressure

rate of filtration formation

Chemoreceptor cells of the JGC found in the ascending limb of the nephron

macula densa

Macula densa cells monitor levels of what in the blood?

NaCl

Mechanoreceptor cells of the JGC located in walls of the afferent artiole?

granular cells/JG/juxtaglomerular

Granular cells

Granular cells detect changes to _____ _______

blood pessure

What enzyme do granular cells of the JGC contain in their secretory granules?

renin

In response to high bP, what cells of the nephron will constrict?

granular cells

What percentage of all oxygen used by the body is used by the kidneys?

20-25%

What is the makeup of filtrate?

• blood plasma WITHOUT PROTEINS

• water

• ions

• waste

• glucose

What fluid contains metabolic wastes + unneeded substances?

urine

At which point of the nephron is the fluid called urine?

distal convoluted tubule

Amount of total fluid processed daily by the kidneys? Amount leaving body as urine?

180 L

1.5 L

What are the 3 processes in urine formation?

glomerular filtration

tubular reabsorption

tubular secretion

Process of hydrostatic pressure forcing fluids + solutes through a membrane?

glomerular filtration

What are the 3 layers of the filtration membrane (in the glomerular capsule) from deep → superficial

• fenestrated endothelium

• basement membrane

• podocytes with filtration slits

What layer of the filtration membrane is fenestrated, allowing fluid, solutes, and plasma proteins to pass while blocking red + white blood cells?

endothelium (innermost)

What layer of the filtration membrane is a negatively charged gel that prevents large plasma proteins from entering tubule?

basement membrane

What layer of the filtration membrane is highly selective and most superficial?

filtration slits of podocytes

What is the equation for Net Filtration Pressure?

HPgc - (OPgc + HPcs)

NFP is calculated subtracting the ______ pressure from ______ pressure

outward

inward

Chief force pushing water + solutes out of the blood across filtration membrane?

hydrostatic pressure in glomerular capillaries

Where in the glomerulus is the blood pressure highest?

glomerular capillaries

What are the two inward forces inhibiting filtrate formation?

osmotic pressure in glomerular capillaries

hydrostatic pressure in capsular space

GFR is the volume of _____ formed per min by ____ ____

filtrate

both kidneys

What three factors is GFR directly proportional to?

• NFP

• surface area available for filtration

• filtration membrane permeability

Normal/average volume of GFR ml/min?

120-125 ml/min

An increase in glomerular filtration rate results in what changes regarding urine output, BV + BP?

urine output increases

BV decreases

BP decreases

GFR being too ___ would cause dehydration + electrolyte depletion

high

GRF being too ____ would cause reabsorption of wastes

low

In cases of GFR being too high, _____ ____ cells detect and trigger constriction of what blood vessel?

macula densa

afferent arteriole

Intrinsic controls/renal autoregulation utilize the ______ to maintain _____?

kidneys

GFR

The myogenic mechanism is a an _______ control

intrinsic

In terms of the myogenic mechanism, an increase of BP would translate to a stretch in what blood vessel? and prompt it to respond how?

afferent arteriole

constrict

Regarding the tubuloglomerular feedback mechanism, what triggers the macula densa cells?

high NaCl concentration/flow rate (GFR)

In the tubuloglomerular feedback mechanism, how do macula densa cells respond to high NaCl concentration?

release vasoconstrictors to afferent arteriole

The extrinsic controls of the urinary system utilize nervous + endocrine mechanisms to regulate GFR to maintain?

blood pressure

In terms of the extrinsic controls of GFR, if the extracellular fluid volume is low, what is released by adrenal medulla?

epinephrine

What does epinephrine do when released by adrenal medulla?

cause vasoconstriction/increase BP

(afferent arterioles also constrict)

In terms of the extrinsic controls, constriction of the afferent arterioles _______ (decrease/increase) GFR? How does this affect BV + BP? (decrease/increase)

decrease

increase

The renin-angiotensin-aldosterone mechanism activates in response to _____ blood pressure

low

In response to low BP what do granular cells secrete?

renin

What three things/pathways activate granular cells?

• sympathetic nerves/low blood volume detected by baroreceptors

• low NaCl detected by macula densa cells

• reduced BP/stretch

In addition to systemic vasoconstriction, Angiotensin II acts on what two areas of the body? and causes the release of what two hormones?

posterior pituitary + adrenal medulla

ADH + aldosterone

How does ADH + aldosterone act on the kidneys/what does it cause?

retention of NaCl + H20

Route of tubular reabsorption in which substances travel through the cell body, active transport!

transcellular

Route of tubular reabsorption in which substances travel between the cells, passive transport!

paracellular

The first step of tubular reabsoprtion, NaCl is pumped from tubule to tubule cell by?

facilitated diffusion

The first step of tubular reabsoprtion of sodium involves NaCl symport with what molecule? or exchanging of what molecule?

glucose

H+

For the second step of tubular reabsorption of sodium, what mechanism allows NaCl to be transported into interstitial fluid?

Na-K pump

For the 3rd step of tubular reabsorption of sodium, how is NaCl transported from interstitial space into peritubular capillaries?

bulk flow, passive

Where are aquaporins always present in the nephron?

PCT

Where in nehphron does ADH cause insertion of aquaporins?

collecting ducts

What hormone causes insertion of aquaporins

ADH

solvent drag is the function of solutes following ____

water

Transport maximum is determined by number of ____ carriers

protein