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The Excretory System. Excretion- removal of waste produced during body functions. Occurs through: Intestine - digestive wastes, salts Skin (sweat glands)- water, electrolytes Lungs - carbon dioxide, water Kidneys - toxins, water, N cmpds, electrolytes. Urinary System Functions.

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Excretion removal of waste produced during body functions
Excretion- removal of waste produced during body functions

Occurs through:

  • Intestine- digestive wastes, salts

  • Skin (sweat glands)- water, electrolytes

  • Lungs- carbon dioxide, water

  • Kidneys- toxins, water, N cmpds, electrolytes


Urinary system functions
Urinary System Functions

  • maintain water concentration in blood

  • maintain concentration of ions like Na & K

  • form urine

  • influence rate of secretion of hormones like ADH

  • alter pH (acid- base balance)

    Why bother with all of these?



Gross anatomy kidney
Gross Anatomy- KIDNEY

  • lie in retroperitoneal position

  • Fat cushion holds it in position

  • medial surface with concave hilus

Not that type….


Gross anatomy kidney1
Gross Anatomy- KIDNEY

  • Cortex- outer and lighter

  • Medulla- inner and darker

1. Cortex region of kidney

2. Medulla region of kidney


Gross anatomy kidney2
Gross Anatomy- KIDNEY

6. Most of the medulla is made up of RENAL PYRAMIDS with a base facing outward and papilla facing the hilus


Gross anatomy kidney3
Gross Anatomy- KIDNEY

7. Cortical tissue dips into the medulla between the pyramids, forming RENAL COLUMNS


Gross anatomy kidney4
Gross Anatomy- KIDNEY

8. Each renal papilla juts into a cup-like CALYX

  • Urine leaving the renal papilla collects here before leaving the body


Gross anatomy kidney5
Gross Anatomy- KIDNEY

9. The calyces join to form the renal pelvis. It narrows as it exits the hilum to become the ureter.


10 blood vessels
10. BLOOD VESSELS

Renal artery brings ¼ of all blood to kidney/min.

Branches into

Interlobar arteries- extend toward the cortex

Changes names

Arcuate arteries- base of pyramids

Changes names

Interlobular arteries- afferent arterioles that branch into the glomerulus where blood is filtered


10 blood vessels continued
10. BLOOD VESSELS (continued)

Efferent arterioles

Peritubular capillaries (vasa recta) Interlobular veinArcuate veinInterlobar veinrenal vein

Blood flows into

But, I am not going to test you on this stuff!


Macroscopic kidneys
Macroscopic Kidneys

A. Capsule & hilus

B. Renal sinus

1. renal pelvis

2. major calyces

3. minor calyces

C. Renal medulla

1. renal pyramids

a. papilla

2. Renal column

D. Renal cortex


B gross anatomy ureter
B. Gross Anatomy- URETER

  • 28 cm long

  • Allows urine to travel from kidney to urinary bladder

  • 3 layers of tissue:

    • Mucous lining

    • Smooth muscle middle

    • DWF outer layer


C urinary bladder
C. URINARY BLADDER

  • behind symphysis pubis

  • mostly smooth muscle aka detrusor muscle lined with transitional epithelium

  • 3 openings: 2 from ureters and one into the urethra

  • Has valve to prevent backflow into kidney

  • Functions

    • urine reservoir

    • aided by urethra, expels urine from body


Male urethra
Male Urethra

Female Urethra


Gross anatomy urethra
Gross Anatomy- URETHRA

  • 3 cm in females; 20 cm in males

  • Male urethra (URINE) passes through prostate gland where it is joined by 2 ejacuatory ducts (SEMEN) then travels through penis and ends at the urinary meatus at the tip of the penis.

  • In females, completely separate from vagina


4 micturition urination
4. Micturition- urination

  • Voluntary relaxation of external sphincter muscle of bladder

  • Detrusor muscle contracts

  • Parasympathetic nerve control

  • Incontinence


Microscopic structure of the nephron
Microscopic Structure of the NEPHRON

  • Filtering unit of kidney

  • Process blood plasma

  • Form urine

  • 1.25 million per kidney

  • Looks like a funnel with a

    long, winding stem


Nephron

Components

1. renal corpuscle

2. PCT

3. loop of Henle

4. DCT

5. Collecting tubule & duct

NEPHRON


The nephron
The Nephron

  • The nephron is the functional unit of the kidney, responsible for the actual purification and filtration of the blood.

  • About one million nephrons are in the cortex of each kidney.


The nephron1
The NEPHRON

RENAL CORPUSCLE- in the cortex

  • Bowman’s capsule

    • Cup-shaped mouth of nephron

  • Glomerulus

    • capillaries in BC

    • Pores (fenestrations)

    • Basement membrane



Microscopic structure of the nephron1
Microscopic Structure of the NEPHRON

PROXIMAL TUBULE- in cortex

  • Closest to BC (“proximal”)

  • Aka PCT (proximal convoluted tubule)

  • Brush border (microvilli) face lumen- increase surface area


The nephron2

cortex

medulla

The NEPHRON

LOOP OF HENLE (LOH)

  • Renal tubule beyond the PCT

    • Descending limb (thin)

    • Sharp turn

    • Ascending limb (thick)

    • Dips into medulla


The nephron3
THE NEPHRON

DISTAL TUBULE

  • Aka DCT (distal convoluted tubule)

  • Beyond LOH (“distal”)

  • Juxtaglomerular apparatus


The nephron4
THE NEPHRON

COLLECTING DUCT

  • Straight tubule joined by distal tubules of several nephrons

  • Fuse to form papillary ducts which deliver urine to the calyces


Overview of kidney function
Overview of KIDNEY FUNCTION

1. FILTRATION

  • Occurs in glomerulus

  • Dependent on Glomerular Filtration Rate (GFR)

  • Filter water and solutes from blood into renal tubule

    • Glucose

    • Amino acids

    • Nitrogen wastes


Kidney function filtration
KIDNEY FUNCTION-Filtration

  • FILTRATION

    • What’s left in the blood?

      • Blood cells

      • Most plasma proteins

    • What causes it?

      • Pressure gradient (high to low)

      • Related to blood pressure


Filtration
Filtration

GFR is directly dependent on blood pressure.a. If GFR (BP) is too high, filtrate flows too fast and substances are NOT reabsorbed

urine flow increases water is lost blood volume drops  blood pressure drops.

b. If GFR (BP) is too low, filtrate flows too slow and substancesare retained too much

urine flow decreases  water is preserved  blood volume increases  blood pressure increases.


Overview of kidney function1
Overview of KIDNEY FUNCTION

2. REABSORPTION

  • Occurs in mostly in PCT and little in LOH, DCT, CD

  • Put good things in the renal tubule back into the blood (peritubular capillaries)

    • Water

    • Electrolytes

    • Nutrients


Overview of kidney function2
Overview of KIDNEY FUNCTION

  • REABSORPTION

    • Healthy kidneys reabsorb

      • Glucose (if not…)

      • Amino acids

      • Sodium

      • Water


Overview of kidney function3
Overview of KIDNEY FUNCTION

  • REABSORPTION

    • Substances that are NOT reabsorbed fully

      • Things that lack carriers

      • Things that are not lipid soluble

      • Things that are too large

      • Examples: urea, creatinine, uric acid


Overview of kidney function4
Overview of KIDNEY FUNCTION

  • REABSORPTION

    • ADH causes the distal and collecting tubules to become more permeable to water

    • This allows hypertonic urine to be formed


Overview of kidney function5
Overview of KIDNEY FUNCTION

  • SECRETION

    • PCT mostly

    • Reabsorption in reverse

    • Movement of small molecules out of the peritubular blood and into the tubule for excretion

      • Including K, H, urea, ammonia

      • Dispose certain drugs

      • Helps control blood pH


Review questions
Review Questions

  • Do you know the names of the structures?

  • What is GFR? What regulates it?

  • Why is reabsorption important?

  • Where is the only place glucose is reabsorbed?

  • Where does ADH act? What does it do?


Making urine
Making Urine

  • Choose your water solution (Normal or Dehydrated)

  • Fill the cup 2/3 of the way with that solution

  • Add ½ dropper of Urea + vitamins

  • Add ½ dropper of acid

  • Check pH with pH paper

  • If you desire, pimp your urine with 1 dropper of the following:


Answer the following questions on a piece of paper and turn it in
Answer the following questions on a piece of paper and turn it in?

  • Did you drink the urine?

  • What type did you make?

  • How did it taste?

  • Did it taste like you expected?

  • If you did not drink it, why not? (please provide at least three reasons)


Urine composition
URINE COMPOSITION it in?

  • Water- 95%

  • Other substances- 5%

    • Nitrogen wastes

    • Electrolytes

    • Toxins

    • Pigments

    • Hormones

    • Abnormal stuff like blood, glucose, casts, calculi


Urine composition1
URINE COMPOSITION it in?

  • Characteristics

    • Color

    • Compounds

    • Slight odor

    • 4.6-8.0 pH (fresh is acidic)

    • 1.001- 1.035 specific gravity


Fluid electrolyte and acid base balance
FLUID, ELECTROLYTE, and it in?ACID-BASE BALANCE

  • FLUID

    • Water accounts for 50-60% total weight (why less in obese people?)

      • 37% of this is ECF

      • 63% of this is ICF


Fluid electrolyte and acid base balance1
FLUID, ELECTROLYTE, and it in?ACID-BASE BALANCE

  • Mechanisms to maintain fluid balance

    • Volumes of ICP, ECF, plasma, and total volume of water relatively constant

    • Adjust output (urine volume) to intake

    • Adjust fluid intake (liquids we drink, water in food we eat, water formed by catabolism)


Anatomy of micturition incontinence
Anatomy of Micturition & Incontinence it in?

  • Detrusor muscle with an External and Internal sphincter

  • Normal capacity 300-600cc

  • First urge to void 150-300cc

  • CNS control

    • Pons - facilitates

    • Cerebral cortex - inhibits

  • Harmonal effects - estrogen



Treatment options
Treatment Options it in?

  • Reduce amount and timing of fluid intake

  • Avoid bladder stimulants (caffeine)

  • Use diuretics judiciously (not before bed)

  • Reduce physical barriers to toilet (use bedside commode)

1


Pessaries it in?


Predisposing conditions to uti
Predisposing conditions to UTI it in?

  • Female

  • Short urethra, proximity to anus, termination beneath labia

  • Sexual activity

  • Pregnancy

    • 2-3% have UTI in preg, 20-30% with asx bacteriuria

  • decreased ureteral peristalsis, temp. incomp ofvesicoureteral valves


Urethritis
Urethritis it in?

  • 􀂃 Acute dysuria, frequency

  • 􀂃 Often need to suspect sexually

  • transmitted pathogens esp. if sx more than 2 days, no hematuria, no suprapubic

  • pain, new sexual partner, cervicitis


Cystitis
Cystitis it in?

  • Sx: frequency, dysuria, urgency, suprapubic pain

  • Cloudy, malodorous urine (nonspec.)

  • Leukocyte esterase positive = pyuria

  • Nitrite positive (but not always)

  • WBC (2-5 with sx) and bacteria on urine microscopy


Nephrolithiasis kidney stones
Nephrolithiasis: kidney stones it in?

  • Supersat. of urine by stone forming constituents

  • Freq. stone types: Calcium (most common), struvite, oxalate, uric acid

  • Risk factors: metabolic disturbances, previous UTI, gout, genetic

  • Incidence = 2-3%

  • Hematuria (rarely dangerous by itself)

  • Dangerous combo = obstruction + infection


Addison s disease
Addison’s Disease it in?

Addison's disease occurs when the adrenal glands do not produce enough of the hormone cortisol and, in some cases, the hormone aldosterone


Cystocele
Cystocele it in?

the wall between a woman’s bladder and her vagina weakens and allows the bladder to droop into the vagina

  • mild—grade 1—when the bladder droops only a short way into the vagina.

  • severe—grade 2—the bladder sinks far enough to reach the opening of the vagina.

  • advanced—grade 3—cystocele occurs when the bladder bulges out through the opening of the vagina.


Nocturnal enuresis
Nocturnal enuresis it in?

  • Hormonal problems.

  • Bladder problems.

  • Genetics.

  • Sleep problems.

  • Medical conditions

  • Psychological problems.


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