Human Anatomy & Physiology: urinary system Flashcards

-regulate water volume and osmolarity in the body
-regulate concentration of ions
-ensure acid base balance
-excreting metabolic wastes and drugs/toxins
-produce erythropoietin and renin that regulate RBC production and BP
-convert vitamin D actively (produced in skin, inactively, and activates in kidney and liver)
-filters 200 liters of fluid

(retroperitoneal position, right and left lumbar abdominopelvic region).

-Urinary bladder - temporary storage reservoir for urine➢Muscular sac for temporary storage of urine
➢Openings for ureters and urethra
➢Layers of bladder wall
i.Mucosa - transitional epithelial mucosa
ii.Thick detrusor - three layers of smooth muscle
iii.Fibrous adventitia (peritoneum on superior surface only)
➢Collapses when empty; rugae appear
i.Expands and rises superiorly during filling without significant rise in internal pressure
ii.Full bladder 12 cm long; holds ~ 500 ml
iii.Can hold ~ twice that if necessary
iv.Can burst if overdistended

-Urethra transports urine out of body➢Muscular tube draining urinary bladder
➢Sphincters
➢Internal urethral sphincter
i.Involuntary (smooth muscle) at bladder-urethra junction
ii.Contracts to open
➢External urethral sphincter
i.Voluntary (skeletal) muscle surrounding urethra as it passes through pelvic floor
➢Female urethra (3–4 cm)
➢Male urethra carries semen and urine

➢ Cortical nephrons—85% of nephrons; almost entirely in cortex
➢ Juxtamedullary nephrons
i. Long nephron loops deeply invade medulla
ii. Ascending limbs have thick and thin segments
iii. Important in production of concentrated urine

1. Juxtamedulliary- efferent arteriole to vasa recta

2. Cortical- efferent arteriole to peritubular capillaries

.(Juxtamedullary has longer loop of Henle than cortical. However, corticalare much more numerous.Cortical nephrons barely extend into the medulla. Juxtamedullary nephrons extend much further down into the medulla)

• Renal artery supplies blood to kidney. This blood is used for energy and metabolism of kidney cells and also is used for filtration of wasteful materials
• deliver one-fourth of the total cardiac output (about 1200 ml) to the kidneys each minute.

Jg cells tell when the blood pressure drops

-leads into the renal sinus
-where the ureter, renal blood vessels, and lymphatics, and nerves all join the kidney

1. Filtration(glomarilous) strains toxins out.

2.Reabsorption (mostly in PCT ) body is taking something something out, under hormonal control-ADH, aldosterone), goes back into the body because it is something it needs to keep.(H2O-ADH) Na+ is absorbed.

3. Secretion- Body has too much and wants to get rid of sodium potassium water mostly in the DCT, can happen elsewhere but mostly in the DCT/ACT- then you get urine.

glomerular capsule (capsular filtrate) → PCT (tubular fluid) → nephron loop → DCT → collecting duct → papillary duct (urine) → minor calyx → major calyx → renal pelvis → ureter → urinary bladder → urethra.

main point to know is that without blood pressure there is no NFP .

huge amounts of filtrate can be produced even with theusual modest NFP of 10 mm Hg. The opposite side of this“coin” is that a drop in glomerular pressure of only 18% stopsfiltration altogether.The GFR is directly proportionalto the NFP, so any change inany of the pressures acting at the filtration membrane changesboth the NFP and the GFR. In the absence of regulation, an in-crease in arterial (and glomerular) blood pressure in the kid-neys increases the GFR. As we shall see in the next sectionhowever, GFR is tightly regulated.Regulation of Glomerular Filtrati

125 min/ml

Be able to ID and give function of the following parts of a nephron: glomerulus, Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting duct, afferent arteriole, efferent arteriole, peritubular capillary, vasa recta.

• filtration happens here filteres out toxins
• consists of 50 intertwined capillaries
• projects into the glomerular (Bowman's) capsule
• blood leaves the glomerulus in an efferent arteriole

Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sac at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac.

• reabsorption of water, ions, and all organic matter
• cuboidal cells with abundant microvilli

Descending Limb of Loop of Henle

• further reabsorption of water
• squamous cells

Ascending Limb of Loop of Henle

• reabsorption of sodium and chloride ions
• low cuboidal cells

• secretion of ions, acids, drugs, and toxins
• variable reabsorption of water, sodium ions, and calcium ions
• cuboidal cells with few microvilli

collecting ducts, each of which receives filtrate frommany nephrons, run through the medullary pyramids and givethem their striped appearance. As the collecting ducts approachthe renal pelvis, they fuse together and deliver urine into the mi-nor calyces via papillae of the pyramids

The afferent arteriole carries blood from the renal artery into the glomerulus, where it divides to form a circulatory network. At the distal end of the glomerulus, the capillaries rejoin to form the efferent arteriole through which blood leaves the glomerulus.

The efferent arterioles are blood vessels that are part of the urinary tract of organisms. The efferent arterioles form from a convergence of the capillaries of the glomerulus. They play an important role in maintaining the glomerular filtration rate despite fluctuations in blood pressure. they are smaller in diameter than afferents thus create resistance.

The peritubular capillariesarise from the efferent arteriolesdraining the glomeruli. These capillaries cling closely to adja-cent renal tubules and empty into nearby venules. They are low-pressure, porous capillaries that readily absorb solutes andwater from the tubule cells as these substances are reclaimedfrom the filtrate

bundles of long straight vessels called vasa recta(vasah rektah; “straight ves-sels”) that extend deep into the medulla paralleling the longestloops of Henle. The thin-walled vasa recta play an importantrole in forming concentrated urine,

????? One per nephron
➢ Important in regulation of rate of filtrate formation and blood pressure
➢ Contains
i. Chemoreceptors; sense NaCl content of filtrate
ii. Mechanoreceptors; sense blood pressure in afferent arteriole

• turned on by renin
• reabsorbs water from filtrate
• mostly in PCT

...

A hormone released from the pituitary gland that causes water reabsorption in the kidneys, thus concentrating the urine

➢ Chemicals that enhance urinary output
i. ADH inhibitors, e.g., alcohol
ii. Na+ reabsorption inhibitors (and resultant H2O reabsorption), e.g., caffeine, drugs for hypertension or edema

Inhibits body from absorbing ADH

protein (albumen), wbc, rbc, glucose

urea, uric acid, na,k, nitrogenous waste,

collecting ducts, papillary ducts, minor calyx, major calyx, renal pelvis,ureter,bladder,urethra,urethral orifice

XXVI. Micturition

➢Urination or voiding
➢Three simultaneous events must occur
i.Contraction of detrusor by ANS
ii.Opening of internal urethral sphincter by ANS
iii.Opening of external urethral sphincter by somatic nervous system
➢Reflexive urination (urination in infants)
➢Pontine control centers mature between ages 2 and 3

The urethral sphincter is crucial for the maintenance of urinary continence [1,2]. The urethral sphincter refers to one of the following muscles [3]: 1) the internal urethral sphincter (IUS), which consists of smooth muscle and is continuous with the detrusor muscle and under involuntary control, and 2) the external urethral sphincter (EUS), which is made up of striated muscle and is under voluntary control.

➢Color and transparency
i.Clear
ii.Cloudy may indicate urinary tract infection
iii.Pale to deep yellow from urochrome
iv.Pigment from hemoglobin breakdown; more concentrated urine → deeper color
v.Abnormal color (pink, brown, smoky)
vi.Food ingestion, bile pigments, blood, drugs
➢Odor
i.Slightly aromatic when fresh
ii.Develops ammonia odor upon standing as bacteria metabolize solutes
iii.May be altered by some drugs and vegetables
➢pH
i.Slightly acidic (~pH 6, with range of 4.5 to 8.0)
ii.Acidic diet (protein, whole wheat) → ↓ pH
iii.Alkaline diet (vegetarian), prolonged vomiting, or urinary tract infections → ↑pH

XXVI. Micturition

➢Urination or voiding
➢Three simultaneous events must occur
i.Contraction of detrusor by ANS
ii.Opening of internal urethral sphincter by ANS
iii.Opening of external urethral sphincter by somatic nervous system
➢Reflexive urination (urination in infants)
➢Pontine control centers mature between ages 2 and 3

The urethral sphincter is crucial for the maintenance of urinary continence [1,2]. The urethral sphincter refers to one of the following muscles [3]: 1) the internal urethral sphincter (IUS), which consists of smooth muscle and is continuous with the detrusor muscle and under involuntary control, and 2) the external urethral sphincter (EUS), which is made up of striated muscle and is under voluntary control.

inhibits detrusor contraction, internal urethral sphincter closes,sometic reflex contracts external urethral sphincter, will not pee

excites the detrusor muscles, inhibits internal urethral sphincter, ok to pee

1. Hypocalcemia is when calcium level in the blood is to low
2. Possible cause: burns, vit. D deficiency, renal rubular disease, renal failure.
3.Consequences: tingling of fingers, tremors, skeletal muscle cramps, tetany, convulsions, depressed excitablility of heart, osteomalacia, and fractures

1. Hypercalcemia is when calcium level in the blood is to high.
2. Possible causes: hyperparathyroidism, excessive vit.D, prolonged mobility
3.Consequences: decreased neuromuscular excitability, cardiac arrhythmias, and arrest

1. Hypochloremia is when chlorine levels in the blood are to low.
2. Possible causes: Metabolic alkalosis(due to vomiting or ingesting to much alkaline substances)or aldosterone deficiency
3.Consequences: no direct clinical symptoms

1. Hyperchloremia is when chlorine levels in the blood are to high
2. Possible causes: dehydration
3. Consequences: no direct clinical symptoms

1. Hypokalemia is when blood potassium level is to low.
2. Possible Causes: GI tract disturbances, starvation, diuretic therapy.
3. Consequences: Cardiac arrhythmias, muscle weakness

1. Hyperkalemia is when blood potassium level is to high
2. Possible cause: renal failure, deficit of aldosterone
3. Consequences: Nausea, vomiting, diarrhea, Bradycardia, cardiac arrhythmias.

1.Hyponatremia is when sodium ion concentrate is plasma is below normal.
2.Possible Cause: solute loss or water retention
3. Consequences: Impacts nervous system, neurologic disfunction

1. Hypernatremia is elevated sodium in the blood
2. Possible cause: could be because of dehydration
3. Concequence:Nervous system impact, thirst, dehydration leads to confusion and lethargy progressing to coma.