BSC 2086 A & P 2 Professor Tcherina Duncombe Palm Beach State College

• Filter plasma, separate and Functions eliminate wastes

•Regulate volume and pressure

•Regulate osmolarity of body fluids by control

•Secrete enzyme

•Secrete

•Acid-base balance • Detoxify using peroxisomes

• •Gluconeogenesis: starvation

- - - Nitrogenous Wastes

•

– proteinsamino acids NH2 removed forms ammonia, liver converts to urea • – nucleic acid catabolism • – creatine phosphate catabolism • Renal failure – : BUN, nitrogenous wastes in blood – : toxic effects as wastes accumulate

23-5 Location

23-6 Anatomy of Kidney

• Renal : outer 1 cm • : renal columns, pyramids - papilla • Lobe of kidney: pyramid and it’s overlying cortex 23-7 Blood Supply Diagram

23-8

• Glomerular filtrate collects in capsular space, flows into renal

23-9 Lobe of Kidney

23-11 Membrane • Fenestrated – 70-90nm pores exclude blood cells • – proteoglycan gel, negative charge excludes > 8nm – 7% , glomerular filtrate 0.03% • Filtration slits – arms have pedicels with negatively charged filtration slits, allow particles < 3nm to pass

• • 23-12 Nephron Diagram

• Peritubular shown only on right 23-13 Renal (Uriniferous) Tubule • Proximal convoluted tubule (PCT) – longest, most coiled, simple cuboidal with brush border • Nephron loop - U shaped; descending and ascending limbs – thick segment (simple cuboidal) initial part of descending limb and part or all of ascending limb, of salts – thin segment (simple squamous) very water permeable • (DCT) – cuboidal, minimal microvilli

23-14 Renal (Uriniferous) Tubule 2 • Collecting duct – several DCT’s join

• Flow of glomerular filtrate: – glomerular capsule  PCT  nephron loop  DCT  collecting duct  papillary duct  minor calyx  major calyx  renal

23-15

• True proportions of nephron loops to convoluted shown • Cortical nephrons (85%) – short nephron loops – efferent arterioles branch off • Juxtamedullary nephrons (15%) – very long nephron loops, maintain salt gradient, helps conserve water

23-16

Urine Formation Preview ( Plasma to )

Glomerular filtrate

Tubular fluid

Urine (collecting duct)

23-20 Filtration Membrane Diagram

23-21

Filtration Pressure • GFR: filtrate formed/min

•Females: 150 L/day • nephrosclerosis •Males : 180L/day

•Urine: 1-2L/day

23-23 Juxtaglomerular Apparatus

Regulation:

• Myogenic

•Tubuloglomerular

- vasomotion

- monitor salinity 23-24 Tubular and

23-25 Renal Autoregulation of GFR •  BP  constrict afferent arteriole, dilate efferent •  BP  dilate afferent arteriole, constrict efferent • Stable for BP range of 80 to 170 mmHg (systolic) • Cannot compensate for extreme BP

23-26 Negative Feedback Control of GFR

23-27 Mechanisms of Reabsorption in the Proximal Convoluted Tubule

2 Routes

23-28 Effects of II

23-29 Countercurrent Multiplier of Nephron Loop Diagram

23-30 Maintenance of Osmolarity in Renal Medulla

23-31 Summary of Tubular Reabsorption and Secretion

23-32 Male Bladder and Urethra

• 18 cm long • Internal urethral sphincter • External urethral sphincter 3 regions during orgasm receives semen passes through pelvic cavity

23-33 Urinary Bladder and Urethra - Female

23-34 Female Urethra

• 3 to 4 cm long • External urethral orifice – between vaginal orifice and clitoris • Internal urethral sphincter – thickened, , involuntary control External urethral sphincter skeletal muscle, voluntary control

23-35 Neural Control of Micturition

23-36 Hemodialysis

23-37

Coupled Channel

Collecting Duct: Water conservation/urine concentration

•Water • Collecting Duct Concentrates Urine

• Osmolarity 4x as concentrated deep in medulla • Medullary portion of CD is more permeable to water than to NaCl 23-42 •Returns salt to medulla •Multiplier •Recaptures salt

Composition and Properties of Urine • Appearance – almost colorless to deep amber; yellow color due to urochrome, from breakdown of hemoglobin (RBC’s) • Odor - as it stands bacteria degrade urea to ammonia • Specific gravity – density of urine ranges from 1.001 -1.028 • Osmolarity - (blood - 300 mOsm/L) ranges from 50 mOsm/L to 1,200 mOsm/L in dehydrated person • pH - range: 4.5 - 8.2, usually 6.0 • Chemical composition: 95% water, 5% solutes – urea, NaCl, KCl, creatinine, uric acid

23-45

Renin-Angiotensin-

23-47 Aldosterone Regulation Antidiuretic Hormone Antidiuretic Hormone

Atrial Natriuretic Peptide Parathyroid gland: calcium regulation

Voiding Urine - Micturition • 200 ml urine in bladder, stretch receptors send signal to sacral spinal cord • Signals ascend to – inhibitory synapses on sympathetic neurons – micturition center (integrates info from amygdala, cortex) • Signals descend to – further inhibit sympathetic neurons – stimulate parasympathetic neurons • Result – urinary bladder contraction – relaxation of internal urethral sphincter • External urethral sphincter - corticospinal tracts to sacral spinal cord inhibit somatic neurons23-57 - relaxes