URINARY SYSTEM -CHAPTER 19 ANATOMY & PHYSIOLOGY

Endothelial cells

The thin layer of cells that line the interior surface of all blood vessels. Only one cell thick in capillaries.

Bowman's capsules

The top of the nephron

path of the blood through the kidneys

glomerulus, efferent arteriole, peritubular capillaries, renal vein

When blood plasma passes through the glomerulus and Bowman's capsule

important nutrient essential to the body are also filtered

Alkalosis

ph above 7.45

Acidosis

ph below 7.35

Buffer systems maintain pH balance by

preventing dramatic changes in hydrogen ion concentration

Renal tubules

proximal and distal convoluted tubules and loop of Henley

Receptors in the distal tubule

react to low sodium

Renal medulla

Inner portion of kidney, pyramids

blood leaves the urine via

the ureters

ADH targets

The collecting ducts

Nephron

each of the functional units in the kidney, consisting of a glomerulus and its associated tubule, through which the glomerular filtrate passes before emerging as urine. There are 1 million per kidney. (there two types of nephron: Cortical and juxtamedullary

The renal pelvis drains directly

into the ureter

As water leave the loop of Henley

ions glucose and amino acids find the way back into the bloodstream through the peritubular capillaries.

The juxtaglomerular apparatus

is a specialized structure formed by the distal convoluted tubule and the glomerular afferent arteriole. It is located near the vascular pole of the glomerulus and its main function is to regulate blood pressure and the filtration rate of the glomerulus.

Trigone

is a triangular shape estructure in the floor of the bladder, marked by the opening of the two ureters

Glomerular capsule

is another name for the Bowman's capsule, a structure surrounding the glomerulus, that performs the first step in the filtration of blood to form urine.

the external urethal sphincter

is made of skeletal muscle

Tubular reabsorption

is the movement of substances from tubular fluid back into the blood.

Urine production

kidney produces 180 liters per day of filtrate, only 1 to 2 liter of urine is produced, each day filtrates is reabsorbed back into the blood to several locations along the tubules

Distal convoluted tubule

main target for aldosterone regulates sodium potassium and PH

Bicarbonate is key in:

maintaining PH homeostasis

RENAL TUBULE

microscopic tube in the kidney where urine is formed after filtration

ADH make the walls of the conducting tubes

more permeable to water, as a result more water will be reabsorbed and less water will be secreted with urine.

fluid balance

negative feedback mechanism maintain composition and volume of body fluids, kidney activity helps keep water volume and electrolyte constant by adjusting the loss of water and dissolve substances in the urine.

Aldosterone

secreted by the adrenal glands, stimulates the kidneys to reabsorb more sodium, and therefore more water, resulting in concentrated urine & an increase blood pressure & volume (water retention)is release when BP is too low or potassium is too high

Reabsorption

substances being return to the blood after kidney filtration

In the presence of ADH

the collecting ducts concentrates the urine and reduces the volume excreted.

ORGANS OF THE URINARY SYSTEM:

-2 kidneys -2 ureters -bladder -urethra

other kidney functions

-Excretion of unwanted substances -Urea elimination -homeostasis of body fluids -blood pressure regulation -hormone production (EPO) -control blood PH

Part of the urinary system

-Kidneys -Urinary Bladder -Urethra

What are the three hormones secreted by the kidneys

-Renin -Erithropoietin -Vitamin D

role of the kidneys in acid balance and PH

-The kidneys also play an important role in maintaining acid-base homeostasis by regulating the* pH of the blood plasma*. -To maintain the acid-base balance: reabsorb bicarbonate from urine, and excrete hydrogen ions into urine.

Different roles of the kidneys

-blood pressure regulation -hormone production -maintain acid balance -productions of red blood cells -electrolyte balance

what vessels suplply blood to the kidneys

-inferior vena cava -abdominal aorta

substances found in urine

-urea (product of protein metabolism) -uric acid -creatinine (muscle creatine) 2. -electrolytes/sodiun,ions, chloride,sulphate, phosphate -pigments, like urochrome, yellow substance giving urine its color, is derived from the breakdown of hemoglobin -billirubin -bile pigments -vitamins, food dyes

how many ureters in the urinary system

........ 2 ureteres

Summary of urine formation

1. *Glumerular filtration*: moves water and solutesfrom the blood into the proximal convoluted tube of the nephron. 2. *Tubular reabsorption*: moves water and other useful substances back into the blood 3. *Tubular secretion*: moves unfiltered or reabsorbed substances from the blood i nto the nephron for elimination.

Which percent of body weight is composed of interstitial fluid?

15%

Average ph in urine

4.5 to 8.0

Anything above

7.0 is alkaline

Urine is approximately

95% water and 5% dissolved solid and gases (fresh urine average PH 6.0 ranging from 4.5 to 8.0)

How urine is produced

Filtration, reabsorption, and secretion

Glomerulus

A ball of capillaries surrounded by Bowman's capsule in the nephron and serving as the site of filtration in the kidney.

ADH or vassopresin

ADH is also called arginine vasopressin. It's a hormone made by the hypothalamus in the brain and stored in the posterior pituitary gland. It tells your kidneys how much water to conserve. ADH constantly regulates and balances the amount of water in your blood

Glomerular filtrate

Fluid forced from the blood out of the capillaries of the glomerulus into the Bowman's capsule. Composed of water, salts, glucose and urea.

Angiotensin II

Angiotensin stimulates numerous processes that all raise blood pressure.

Afferent arteriole

Baroreceptors that detect a increase in blood volume, arterial blood pressure above normal

Kidney failure is caused by:

Build up of toxic waste Lowing of pH (acidosis) secrete influx of H+ Electrolyte imbalances (secrete K+ from action potential) - K+ retention - Na+ levels depend on Na+ intake Loss of Plasma proteins = Edema (loss of plasma proteins) Inability to vary urine concentration, body fluids can become hypo or hypertonic. Anemia = Inadequate erythropoietin production (not secreting RBC) (Endocrine System)

Afferent Artery

Carries blood into the kidney

The kidney take 180mL per day, but only one liter of urine is produced

Efferent artery branches out form capillaries which surround the tubules of the nephron. re absorption is the movement of substances out of the tubules across the surrounding interstitial fluid

Low blood pressure

Estimulates the release of Aldosterone and ADH is released in the presence of high blood pressure. plasma/sodium concentration controls ADH directly to regulate water retention, which ultimately will lower blood pressure.

Fluid balance II

FB II . The constancy of body fluid is maintain this way: 1. Thirs mechanism 2. Kidney activity helps keep water volume and electrolytes constant by adjusting the loss of water and dissolved substances in the urine. 3. Buffers,respiration and kidney function regulates body PH (acidity or alkalinity)

Tonicity Effect on (GFR) Glomerular Filtration Rate

Hypotonic body fluids; too much water = increased GFR Hypertonic body fluids; too little water = decreased GFR

water rebsorption

Is controlled by the ADH (anti-diuretic hormone) as the blood become more concentrated, the hypothalamus releases ADH from the posterior pituitary gland, in the disease diabetes insipidous, there is an adecaute secretion of ADH

The male urethra

Is larger than the female approx. 20 cm 8 in. it serves as draining system and reproductive

Renin

Is produced by the kidneys, is an enzyme that activates the protein *angiotensin* which increases blood pressure.

Glomerular filtration

Is the process by which plasma 20%, and dissolved substances (Na+, K+, Ca+) pass through capillaries into the Bowman's capsule. Cells & plasma proteins remain in capillaries (can't escape) Circulate in peritubular capillaries

One of the functions of the kidneys is

Kidneys play a critical role in fluid balance, regulating balance of salt and water

loop of Henley

Middle portion of renal tubule

filtration

Plasma moving from the glomerulus to the Bowman's capsule

The kidneys are located

Posterior to the peritoneum

Erythropoietin

Secreted as a response to low O2 in renal artery, stimulates red blood cell (RBC) production in the bone marrow

Hormonal Control of Kidney Function - Antidiuretic hormone (ADH or Vasopressin

Secreted by the posterior pituitary gland if: Blood Volume is too low Distal convoluted tubule & Collecting duct become permeable to water (without ADH> Impermeable to water Reabsorption of water is increased, thereby conserving water, reducing the volume of urine.

ADH or Vassopresin

Secreted by the posterior pituitary gland, stimulates the kidneys to reabsorb water resulting in concentrated urine & an increase blood pressure & volume (if too much water in the body then ADH will be blocked in order to excrete dilute urine)

Vitamin D

Secretion of its active form (Cacitriol) which promotes calcium absorption from the gut

Substances reabsorbed by the Proximal Convoluted Tubule

Sodium, Amino Acids, Glucose. in this part essential ions are absorbed

Efferent arteriole

The arteriole that carries the concentrated blood (more cells, less plasma) away from the glomerulus and to the peritubular capillaries. It has a smaller lumen than the afferent arteriole.

Efferent Artery

The efferent arteriole carries blood away from the glomerulus into the tubules.

The loop of Henley is situated in the medulla

The medulla in the descending tube is very salty and concentrated, as the water leaves the concentration is greater and water is moved out back into the blood leaving behind more concentration.

The loop of Henley

The nephron structure that is especially important in the kidney's ability to produce urine of varying concentration; 15% of reabsorption takes place.

The glomerulus

The specialized nephron capillary bed where filtration occurs

steps of urine production

There are three main steps of urine formation: glomerular filtration, reabsorption, and secretion.

tubular reabsorption

Urine is formed by three processes. In this process the filtrate components that are useful to the body move from the nephron into the blood?

Proximal convoluted tubule

Where the greatest percentage of Na+ /sodium (65%) reabsorption takes place. is lining with villi that increases its surface area,,as well as the absorption rate. Active/passive transport take place(ATP) inside the tube

lobular artery

branches into Afferent and efferent

An excess of ADH

can cause water intoxication

urethra

carries urine from the bladder to the outside of the body

URINARY SYSTEM

also known as the renal system, consists of the kidneys, ureters, bladder, and the urethra. Each kidney consists of millions of functional units called nephrons

buffers

are substances that prevent drastic changes in hydrogen ion (H+), they work accepting or releeasing ions to keep PH steady.

The kidneys

are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid.

cystecthomy

bladder removal

Function of the nepron

blood enter the nephron through the afferent artert into the *glomerulus* and leave by the efferent artery, as this occurs component of the blood are filtered out into an area called t he* Bowman's capsule*, the filters components are calectively called *glumerulus filtrate pass on into the tubules eventually filtrate enters the last part the collecting ducts exiting as urine.

Renal Artery

blood vessel that carries blood to the kidney, branching from the abdominal aorta