Anatomy and Physiology Chapter 15 The Urinary System Anatomy and Physiology Chapter 15 https://www.youtube.com/watch?v=cc8sUv2SuaY&list=PL3nYDHNcrNncbhhdm-8C9NOWTLfyHtbPK&index=8

Vocabulary Slide 1 Renal cortex Loop of Henle Renal medulla Distal convoluted tubules Medullary pyramids Collecting duct Renal pelvis Peritubular capillaries Hilus Urethra Glomerulus Ureter Afferent arterioles Sphincter Efferent arterioles Incontinence Bowman’s capsule Hyperplasia Proximal convoluted tubules Aldosterone Diabetes insipidus 516

Answer these Slide 2 What is the job of the kidneys? List 3. p502 What 2 other parts of the body aid in excretion? 502 Approximately how many nephrons does each kidney contain? 505 What are the 2 main structures of the nephron? 505 Put these in the correct order. proximal convoluted tubule, distal convoluted tubule, loop of Henle 505 Which part of the kidney are the nephrons located? What causes fluids and small solutes out of the blood & into the Bowman’s capsule? 505

Answer these Slide 3 What 3 processes are needed to form urine? 507 What substances are typically reabsorbed by the tubules? 507 Name 4 physical features of the bladder. How much urine can the average adult bladder hold? 512-3 What causes urine to move down the ureters? 512 Tell the difference between the internal urethral sphincter and external urethral sphincter. 513 What % does water make up in female & male bodies? 514

Slide 4 Name 5 situations where incontinence is considered normal? 514 What is one time in life it is normal? 521 What is the difference of intracellular fluid and extracellular fluid? 515 When blood pH rises, the respiratory system is _____. What does this do for the blood? 520 What organ most controls blood pH? What is the average adult urine output per day? 521 (T/F) Sexually transmitted diseases (STDs) may cause urinary tract infections. 521

Kidneys Dispose of metabolic waste products Regulate blood volume Manufacture urine Convert vitamin d from an Inactive to active form

Nephrons and Urine Formation

Nephrons Structural and functional units of the kidneys Each kidney contains over one million Responsible for forming urine

Nephrons

Nephrons Glomerulus: Renal Tubule: Knot of capillaries Glomerular Capsule: closed end of the renal tubule that surrounds the glomerulus Rest of the tube extends from the glomerular capsule, coils and twists (proximal convoluted tubule) before making a hairpin loop (Loop of Henle) Then it becomes coiled and twisted again (distal convoluted tubule) and enters the collecting duct Tubule cells contain microvilli to increase surface area

Nephrons Cortical Nephrons: Juxtamedullary Nephrons: Most nephrons Located almost entirely within the cortex Juxtamedullary Nephrons: Few nephrons Situated close to the cortex-medulla junction Loops of Henle dip into the medulla

Nephrons Collecting Ducts: Each receive urine from many nephrons Run downward through the medullary pyramids Deliver the urine to the renal pelvis

Nephrons Afferent Arteriole: Efferent Arteriole: Glomerulus: Feeds blood to the glomerulus Efferent Arteriole: Carries blood from the glomerulus Glomerulus: Specialized capillary bed for filtration Extremely high blood pressure forces fluid and solutes out of the blood Most removed fluid and solutes are returned to the blood in the peritubular capillary beds

Urine

Urine Formation Three Major Processes: Filtration Tubular Reabsorption Tubular Secretion

Urine Formation Filtration: Nonselective and passive Filtrate = blood plasma without blood proteins If blood cells or proteins are found in the urine = sign that glomerular filters are malfunctioning Filtrate formation stops if blood pressure drops too low

Urine Formation Tubular Reabsorption: Filtration removes many useful substances from the blood that must be reclaimed Begins as soon as the filtrate enters the proximal convoluted tubule Some is passive, most is active Needed Substances in the blood: water, glucose, amino acids, and ions Nitrogenous waste products are poorly reabsorbed: urea, uric acid, & creatinine

Urine Formation Tubular Secretion: Reabsorption in reverse Gets rid of substances not already in the filtrate, such as certain drugs Moves from blood peritubular capillaries into tubules Additional means for controlling blood pH

Characteristics of Urine In 24 hours the kidneys filter 150-180 L of blood plasma and produces 1-1.8L of urine Freshly voided urine is generally clear and pale to deep yellow Urochrome pigment from destruction of hemoglobin causes yellow color More solutes = deeper color More dense than water Typically contain ammonia Sterile (free from bacteria or microorganisms)

Characteristics of Urine When formed: urine is sterile with a slightly aromatic odor When allowed to stand: ammonia odor due to bacteria Some drugs, vegetables, and diseases alter the odor of urine

Characteristics of Urine Usually slightly acidic – pH 6 Lots of protein and whole wheat = more acidic Vegetarian diet = more basic

Characteristics of Urine Urine is more dense than distilled water Specific Gravity: compare how much heavier urine is than distilled water Ranges from 1.001 to 1.035 (dilute to concentrated) Generally low when a person: drinks excess fluids, uses diuretics, or has chronic renal failure Generally high when a person: has inadequate fluid intake, fever, or kidney inflammation

Characteristics of Urine Solutes Normally Found in Urine: Sodium and potassium ions Urea Uric acid Creatinine Ammonia Bicarbonate ions Other ions

Characteristics of Urine Substances NOT Normally Found in Urine: Glucose Blood proteins Red blood cells Hemoglobin White blood cells (pus) Bile

Fluid, Electrolyte, and Acid-Base Balance

Blood Composition Factors Affecting Blood Composition: Diet Cellular Metabolism Urine Output

Blood Composition Four Major Roles of the Kidneys in Maintaining Stable Blood Composition: Excretion of nitrogenous wastes Maintaining water balance Maintaining electrolyte balance Ensuring proper blood pH

Body Fluids and Fluid Compartments Three Major Fluid Compartments in the Body: Intracellular Fluid Contained within living cells Interstitial Fluid Fluid found between living cells, CSF, serous fluid, humors of the eye, lymph, etc Plasma Blood plasma

The Link Between Water and Salt Types and amounts of solutes in body fluids are vitally important to overall body homeostasis Very small changes in electrolyte balance cause water to move from one compartment to another Alters blood volume and blood pressure Can severely impair the activity of irritable cells

Water In and Water Out Water Intake: Water Output: 10% Metabolism 30% Food 60% Beverages Water Output: 4% Feces 8% Sweat 28% Loss through skin and lungs 60% Urine

NASA recycles in space https://www.youtube.com/watch?v=BCjH3k5gODI&list=PL3nYDHNcrNncbhhdm-8C9NOWTLfyHtbPK&index=11 Water recycling on the ISS https://www.youtube.com/watch?v=DX7HKzk7xGg&index=10&list=PL3nYDHNcrNncbhhdm-8C9NOWTLfyHtbPK Recycling urine

Regulation of Reabsorption When blood volume drops, arterial blood pressure drops, and filtrate formation drops Osmoreceptors in the hypothalamus react to changes in blood composition by becoming more active Antidiuretic Hormone: prevents excessive water loss in urine, causes the collecting ducts to reabsorb more water

Maintaining Acid-Base Balance of Blood Blood pH must remain between 7.35 and 7.45 Respiratory System Controls Release more carbon dioxide when blood pH drops Release less carbon dioxide when blood pH rises Bicarbonate Buffer System Mixture of carbonic acid and sodium bicarbonate Weak acid minimizes effect of bases Conjugate base minimizes effect of acids

Maintaining Acid-Base Balance of Blood Renal Mechanisms Can rid the body of acids other than carbonic acid that are generated during metabolism Regulate blood levels of alkaline substances Slow-acting, but bring about changes Means of Maintaining Acid-Base Balance: Excreting bicarbonate ions Conserving or generating new bicarbonate ions Urine pH ranges from 4.5-8.0 (slightly basic)