Urinary system questions

Hilum

the site of exit for the ureter and renal vein and the site of entrance for the renal artery and nerve.

Excretion, Elimination, Homeostatic Regulation

The 3 main functions of the urinary system

Excretion

Removal of organic waste products from body fluids

Elimination

Discharge of waste products into the environment

Homeostatic Regulation

Regulation of the volume and solute concentration of blood pressure

Regulating blood volume and pressure, Stabilize blood pH, Conserving valuable nutrients

4 other essential homeostatic functions

Kidneys

Produce urine

Ureters

Urine travels through the _____ to the urinary bladder

Urinary bladder

The _____ _____ stores urine until you are ready for excretion

Urethra

Urine leaves the urinary bladder through the _____ and exits the body.

Outer Renal Cortex, Inner Renal Cortex

The Sectional Anatomy of the kidneys

Renal pyramids (of the kidney)

Where the urine production occurs

Renal papilla

The tip of each renal pyramid

Minor calyx

Where urine from the renal papilla is discharged into

Renal pelvis

2 major calyces (4-5 minor calyces) joined together

Nephrons

The basic functional unit of the kidney

Convert filtrates into urine

The role of each segment of the nephron

Cortical (in the cortex)

Juxtamedullary (near the medulla)

The 2 types of nephrons

filtration

When blood pressure forces fluid and dissolved solutes out of the capillaries and into the surrounding capsular space.

filtrates

The solution produced after filtration

Advantage of filtration

It is passive

PCT, Nephron Loop, Distal Convoluted Tubule

The three parts of the renal tubule

Renal tubule

• Reabsorbs all of the useful organic molecules from filtrates and secretes waste products that were missed by the filtration process;

• Reabsorbs over 90% of the wastes lost

Glomercular filtration

produces a filtrate resembling blood plasma but containing few plasma proteins

Vasa vecta

absorbs solutes and water reabsorbed by the the loop of Henle and the collecting ducts

Normal kidney function

Depends on adequate blood flow to maintain filtration pressures and a stable GFR

adjustments in glomerular pressures

Changes in diameter (constriction or dilation) of afferent/efferent arterioles and capillaries

Angiotensin, ADH, Aldosterone, ANP

4 main hormones

Ureters

A part of muscular tubes that conduct urine from the kidneys to the urinary bladder

Urinary bladder

A hollow, muscular organ that stores urine prior to urination

Trigone

• Smooth triangular area outlined by the openings for the ureters and the uretha

• Infections tend to persist in this area

Denstrusor muscle

Contraction of the _____ compresses the bladder and expels its contents into the urethra

Urethra

Extends from the neck of the urinary bladder to the exterior (external urethral orifice) of the body.

external urethral sphincter

contractions here are voluntary

Micturition

urination reflex

200 mL
(sphincters are forced open at 500mL)

The amount necessary for the urinary bladder to be filled enough

When urination begins

internal urethral sphincters relax

To survive the body must maintain normal volume and composition in both _____ and _____

Extracellular (ECF), Intracellular (ICF) fluid

Fluid balance

involves regulation water in the ECF and ICF

Electrolyte balance

gained in food/water & lost through urine, sweat, and feces

Acid-Base Balance

exists when the pH of body fluids is within normal limits

Fluid shifts

• Water movements between the ECF and ICF
  

• Occur in response to changes in osmotic composition

Sodium balance

The most common electrolyte unbalance

Potassium balance

Less common type of electrolyte balance but more dangerous

Acidosis

pH below 7.35

Alkalosis

pH above 7.45

anhydrase

an enzyme that speeds up the reaction of carbonic acid

Buffer systems

• temporarily neutralize acids produced by normal metabolic operations

• Include weak acids and weak bases

Protein buffer systems

contribute to regulation of pH in ECF and ICF

Carbonic acid-bicarbonate buffer systems

important in the ECF;
Prevents pH changes caused by metabolic acids

Phosphate buffer systems

• Important in the ICF;

• consists of an anion

Hydrogen ion gains=losses

In order to maintain acid-base balance

Respiratory and renal mechanisms support buffer systems by:

• secreting or absorbing hydrogen ions

• controlling the secretion of acids and bases

• Generating additional buffers

Respiratory compensations

changes in the respiratory rate that help stabilize the pH of the ECF

Renal compensations

changes in the rate of hydrogen ions and bicarbonate ion secretion or absorption by the kidneys in response to changes in plasma pH

the most important factor affecting pH in body tissues

carbon dioxide partial pressure