Ch 18 Urinary System
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Created by:
DrDavila Plus on April 25, 2012
Subjects:
BIO104: Human Anatomy & Physiology II
Description:
Dr Davila
Medical Careers Institute, ECPI University
Human Anatomy & Physiology II
BIO 104
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56 terms
Terms | Definitions |
|---|---|
 3 urinary system functions | 1. excretion 2. elimination 3. homeostatic regulation |
| excretion | removal of waste from blood |
| elimination | discharge of waste products |
| homeostatic regulation | maintain blood volume (and thus, blood pressure), blood pH, and conserve nutrients |
| kidney | pair of retroperitoneal bean-shaped organs that filter water and waste materials from the blood, producing urine |
| retroperitoneal | posterior to the peritoneum |
| urinary tract | organs that eliminate urine; include ureters, urinary bladder, and urethra |
| ureters | tubes that propel urine via peristalsis from kidneys to bladder |
| urinary bladder | hollow, muscular sac that stores urine until elimination; may hold 1L of urine |
| urethra | conducts urine out of the body; in males also transports semen |
| urination | process of eliminating urine; aka micturition or voiding |
| micturition | urination |
| renal pelvis | funnel-shaped reservoir that collects urine and passes it to the ureter |
| renal cortex | outer layer of the kidney containing the glomeruli and the convoluted tubules |
| renal medulla | inner tissue layer of the kidney; contains loops of Henle and collecting tubules |
| renal pyramid | conical wedges that makes up most of the renal medulla |
| renal colums | bands of cortex tissue that separate the pyramids |
| nephron | microscopic tubular structures that filter blood and produce urine; functional unit of the kidney |
| parts of a nephron | renal corpuscle → proximal convoluted tubule → nephron loop (aka, loop of Henle) → distal convoluted tubule → collecting duct |
| nephron blood supply | afferent arteriole GLOMERULUS efferent arteriole peritubular capillaries vasa recta |
| renal tubule | includes proximal convoluted tubule, nephron loop (aka, loop of Henle), distal convoluted tubule, and collecting duct; PCT→loop→DCT→duct |
| renal corpuscle | Bowman's capsule and glomerulus at the start of a nephron; "little body in kidney"; where filtrate is formed |
| filtrate | fluid from blood squirt through glomeruli pores into the Bowman's capsule; blood serum in nephrons |
| glomerulus | spherical knot of intertwining capillaries; blood is filtered through pores in glomerulus |
| Bowman's capsule | cup-shaped structure of nephron, which encloses the glomerulus; filtration occurs inside here |
| proximal convoluted tubule | first section of the renal tubule that the blood flows through; reabsorption of water, ions, and all organic nutrients |
| nephron loop | second part of tubule that dips into the medulla; reabsorbs water and salt (sodium and chloride ions); aka, loop of Henle |
| distal convoluted tubule | third part of tubule; selectively reabsorbs (water, sodium, calcium) and secretes wastes here, only if needed |
| collecting ducts | last part of tubule, which receives filtrate from many nephrons; selectively reabsorbs water & ions (may secrete ions); delivers urine to calyxes and then renal pelvis |
| purpose of urine production | maintain homeostasis excrete solutes (wastes and excess ions) regulate blood pressure |
| metabolic waste | urea uric acid creatinine |
| 3 urine formation processes | filtration reabsorption secretion |
| filtration | process whereby fluids are forced through a filter; fluid is serum, force is blood pressure, filter is glomerular pores |
| reabsorption | process in nephron that saves useful substances (water, glucose, amino acids) from filtrate back into blood |
| secretion | process whereby nephron actively pumps wastes into filtrate |
| glomerular filtration rate | speed at which gomeruli produce filtrate; affected by blood pressure and volume |
| urinalysis | analysis of a urine sample; important diagnostic tool |
| renin angiotensin system | hormone pathway that increases thirst and raises blood pressure if blood volume falls (often due to dehydration), detected as decreased blood flow to the kidneys; aka RAS or renin-angiotensin-aldosterone system (RAAS) |
| aldosterone | hormone that increases sodium reabsorption, thereby increasing water reabosrption; (recall in osmosis "water follows stuff/salt"); "aldosterone saves sodium" & kicks out K+ [potassium] |
| antidiuretic hormone | signal in blood (from posterior pituitary) that increases water reabsorption from filtrate in nephrons, thereby decreasing urine production; |
| atrial natriuretic peptide | hormone secreted by atria (upon increased blood flow/pressure) which increases sodium excretion; (recall in osmosis "water follows stuff/salt") |
| external urethral sphincter | circular band of voluntary skeletal muscle on pelvic floor; voluntarily relaxes to allow micturition |
| internal urethral sphincter | involuntary smooth muscle at bladder-urethra junction that contracts to open |
| fluid compartments | Intracellular fluid (ICF): approx. 60% of body's water Extracellular fluid (ECF): approx 40% of body's water water flows freely between 2 compartments |
| water balance | water intake equals loss (from feces, urine, and insensensible perspiration); require about 2.5 L daily; 1L from food, 1.2L from drinking, 0.3L from aerobic metabolism |
| fluid shift | rapid water movements between ECF and ICF due to osmosis (ie, more water in one compartment than another) |
| hypertonic ECF | pulls water out of cells and into ECF (more "stuff" than water in ECF); cells shrivel |
| hypotonic ECF | water pushes into cells and out of ECF (more water than "stuff" in ECF); cells swell |
| electrolyte balance | usually referring to the balance of sodium (Na+) & potassium (K+) ions |
| acidosis | processes that result in abnormally low pH ; eg. metabolic and respiratory acidosis |
| acidemia | abnormally low plasma pH <7.35 |
| alkalosis | processes that result in abnormally high pH; eg. CO2 levels too low |
| alkalemia | abnormally high plasma pH >7.45 |
| buffer | resists changes in pH temporarily ; (eg. proteins, carbonic acid, and phosphates all help resist pH changes temporarily) |
| renal compensation | kidney varies acid (H+) secretion and bicarbonate reabsorption depending on pH of ECF; eg. kidney removes excess acid from plasma |
| respiratory compensation | changes in ventilation change pH by increasing or decreasing CO2 levels; eg, lungs exhale plasma acid as CO2 |
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