Chapter 19- Kidneys

regulation of extracellular fluid volume, blood pressure, osmolarity, and ion balance

regulation of extracellular fluid volume, blood pressure, osmolarity, and ion balance

what are the main functions of the kidneys?

Na+, K+, Ca2+

what ions do the kidneys balance?

pH regulation, excretion of waste, hormone production

additional functions of the kidneys

EPO, renin, vitamin D activation

what hormones are produced by the kidneys?

nephrons

series of hollow tubes that produce urine in the kidneys

ureters

paired structures leaving each kidney

smooth muscle structure that stores urine

urethra

singular tube involved in the process of micturition

urethra

structure for conduction of fluid out of the body

capsule

outer connective tissue covering of the kidney

renal cortex

outer region of the kidney

renal medulla

inner region of the kidney

renal pelvis

urine that forms in nephron empties here and then enters ureters

cortical nephrons

nephrons that are located in their entirety here (80%)

juxtamedullary nephron

part of the nephron extends into medulla (20%)

medulla

in which kidney region are all nephrons parallel?

Bowman’s capsule, proximal tubule, loop of henle, distal tubule, collecting duct

what are the structures of the nephron in order of filtration

Bowman’s capsule

hollow ball/cup like epithelial lined structure that surrounds the glomerulus, captures and directs fluid into the rest of the nephron

loop of henle

concentrate urine in order to conserve water→ maintains proper wate rbalance

afferent arteriole

brings blood into the nephron

glomerulous

-tuft of capillaries located in the cortical portion of the nephron;
-Site of blood filtration

efferent arteriole

blood vessel that drains blood from the glomerulus

peritubular capillaries

capillary bed that runs around the tubules of the nephron and picks up fluid/solutes

vasa recta

Capillaries of Juxtamedullary nephrons

renal corpuscle

Bowman’s Capsule + glomerulus

Juxtaglomerular apparatus

-region of final ascending limb that passes between afferent and efferent arterioles
- specialized group of cells that functions in paracrine communication

collecting duct

gather urine to drain into the urinary pelvis

filtration, secretion, reabsorption

3 basic processes of the nephron

filtration

occurs at the renal corpuscle and involves movement of fluid from blood into BC

filtrate

the fluid that passes into nephron

reabsorption

moving substances in filtrate back into the peritubular capillaries

secretion

selectively removing molecules from blood into the filtrate

bulk flow, fluid and solutes, glomerulus, bowman’s capsule

Filtration refers to the _________ of ___________ (not proteins or cells) from the __________ into ____________

filtration fraction

% of the plasma that filters into the tubule

glomeruler endothelium, basement membrane, BC epithelium

what are the components of the filtration barier?

fenestrated with large pores

what type of epithelium is present in the kidney capillaries

podocytes

special cells found in BC epithelium and surround glomerular capillaries with foot processes that form filtration slits

hydrostatic pressure

pressure generated by blood in capillaries

glomerulus

where is hydrostatic pressure high?

colloid osmotic pressure

Pressure generated by plasma proteins

glomerular filtration rate

Volume of fluid filtering into BC per unit time

capillary SA and premeability

what factors affect glomerular filtration rate

180L/day

average glomerular filtration rate?

99

More than ___% of filtered fluid is reabsorbed

proximal tubules

where does most reabsorption take place?

saturation

generates the maximum rate of transport that occurs when all carriers are occupied

transport maximum

rate of transport (mg/min) at saturation

peritubular capillaries

reabsorb fluid and solutes from ECF

hydrostatic, colloid osmotic

during reabsorption, ___________ pressure is less than the __________ pressure

tubular secretion

Selective movement of solutes from the ECF to lumen to be excreted

micturination

Emptying the urinary bladder

continuous

Bladder is __________ with urethra

smooth

Internal sphincter of the bladder is ________ muscle

skeletal

external sphincter of the bladder is ________ muscle

stretch receptors

receptors involved in emptying the bladder

parasympathetic

_____________ signal initiates smooth muscle contraction of the bladder