Chapter 15 The Urinary System

Anatomy of the Kidney General filter all blood every 30 minutes kidneys organs of excretion eliminate nitrogenous wastes (urea) eliminate toxins eliminate drugs excess ions excess water metabolic wastes

Regulate blood volume make enzymes for blood pressure and red blood cell productions composition of system paired kidneys urinary bladder ureters urethra renal blood supply renal artery --> kidney kidney --> renal vein

Nephrons functional unit of kidney glomerulus bowman’s capsule 1 million per kidney, clean blood form urine glomerulus ball of capillaries, forces material to be filtered into bowman’s capsule transports materials (filtrate) into tubule renal tubule 1.25 inches proximal convoluted tubule - reabsorption of water and solutes loop of henle - reabsorption of Na and Cl ions distal convoluted tubule - reabsorption of water Na, Cl collecting tubule contains urine - nitrogenous wastes, water and salts

Label with functions

Urine Formation Filtration Reabsorption Secretion glomerulus blood pressure nonselective Reabsorption tubules --> capillaries materials which need to be returned to blood Secretion capillaries --> tubules get rid of substances not contained in the filtrate

Kidney Control of Blood Composition Nitrogenous wastes urea - break down of proteins uric acid - breakdown of nucleic acids creatinine - breakdown of creatine phosphate CP Water and electrolyte balance water ADH ~ water to be reabsorbed aldosterone ~ causes Na + to be going back to blood polyuria ~ lose water and salt, DEHYDRATED ANH ~ atrail natriueretic hormone lose Na+, lose water electrolytes Na +, K +, Cl -, Ca ++

Blood acid - base balance blood pH 7.35 - 7.45 alkalosis acidosis buffers pH goes up when kidneys excrete bicarbonate ions pH goes down when kidneys reabsorb bicarbonate ions

Urine Characteristics Urinalysis physical aspects – color, clarity, specific gravity, odor chemical aspects - water, urea, salt, ions, pH microscopic aspects – types of cells Characteristics color - clear to yellow clarity - transparent odor - odorless pH - 5.5 to 8 specific gravity - 1.001 - 1.035

Urine output volume abnormal urine 1-2 liters per day 95 % water 5% organic and inorganic volume dilute urine or concentrated urine Factors- heat, amount of sweat produced amount of liquids consumed, salt in diet abnormal urine glucose (glycosuria) , proteins – albumin & ketones, hemoglobin, bile pigments (brown) reddish - blood, liver problem red blood cells - bleeding, kidney stones leukocytes - pus , milky - pus green - bacterial infection

Ureters Structure function Problems kidney stones: slender tubes, 10 -12 inches long function collect and transfer urine from all collecting tubules to bladder Problems kidney stones: Uric Acid - forms crystals Calcium (oxalate or phosphate) Struvite (infection)

Urinary Bladder Functions Urethra Sphincters stores urine 500 ml can hold 1000 ml expels urine 1-2 liters a day Urethra tube thru which urine is expelled males - 8 inches , urine & sperm females - 1.5 inches Urethritis inflammation of urethra Sphincters internal - smooth muscle relaxes 200 -300 ml external – skeletal muscle

Micturition cystitis voiding - empty bladder bladder contracts internal sphincter relaxes and external incontinence - can’t control external sphincter urinary retention - surgery, diseases, use catheter cystitis bladder inflammation can lead to kidney inflammation- pyelitis

Aging of the Urinary System Renal Function decreases with age incontinence increases, nocturia urinary tract infections increase dysuria painful urination polyuria frequent urination oliguria - low urinary output increase in prostate cancer

Disorders Infections E. Coli streptococcus --> glomerulonephritis sexually transmitted diseases polycystic kidney disease