1. Urinary System- Kidney

urinary system

maintain composition, pH, and volume of body fluids → maintain homeostasis. remove metabolic wastes and excess biochemicals, excrete foreign substances

urinary organs

kidneys, ureters, urinary bladder, urethra

kidneys

regulate volume, composition, and pH of body fluids, removes wastes from blood excreting them to outside (erythropoietin, renin) regulates calcium absorption with vitamin D

erthyropoietin

RBC production

renin

blood pressure

kidney structure

renal hilum, renal sinus, renal medulla, renal cortex

renal hilum

entrance to renal sinus where ureters, blood vessels, lymphatic vessels, and nerve enter or exit

renal sinus

hollow chamber of medial depression

renal medulla

inner portion, contains renal pyramids

renal cortex

outer, forms renal columns

nephrons

kidneys functional units, contains renal corpuscle and renal tubule

renal corpuscle

contains glomerulus and Bowman’s capsule

glomerulus

blood capillaries that receives (afferent) and drains (efferent) blood, filters blood to begin urine formation

bowmans capsule

receives filtered fluid, parietal layer and visceral later

bowmans parietal

squamous epithelial

bowmans visceral

podocytes → pedicels → slit pores

renal tubule

forms a hairpin loop with proximal limb, nephron loop, distal limb

distal tubes

form collecting duct

renal arteries

transport blood to kidneys

renal artery →

segmental → interlobar → arcuate → cortical radiate → afferent (RSIACA)

efferent →

cortical radiate vein → arcuate → interlobar → renal (ECAIR)

afferent and efferent meet

in glomerulus

10-15% of blood

enters renal medulla + supplies vasa recta, most stays in renal cortex

flow of filtrate

glomerulus → glomerular capsule → proximal tubule → nephron loop (descending → ascending) → distal tubule → collecting duct → minor calyx → major calyx → renal pelvis → ureter → urinary bladder

cortical nephrons

most abundant, in renal cortex, surrounded by peritubular capillaries

juxtamedullary nephrons

15%, deep in renal cortex in loops digging into medulla, surrounded by vasa recta, regulate water balance and urine concentration

juxtaglomerula apparatus

macula densa

macula densa

ascending limb passes by glomerulus, contains densely packed epithelial cells, monitor NaCl composition of filtrate

juxtaglomerular (JG) cells

within walls of afferent arteriole, release renin