The urinary system

Question 1

What can urine be used for?

Answer 1

to determine alot about the general health and habits about humans.

Question 2

What can changes in the composition of urine show?

Answer 2

metabolic problems, infection,pregnancy, and the presence of illegal performance enhancing drugs in athletes.

Question 3

Why is urine a useful indicator of health?

Answer 3

b/c each day the kidneys filter all the blood in the body a total of 30x eliminating excess water and harmful solutes.

Question 4

Extracellular fluid

Answer 4

is compromised of tissue fluid, blood plasma, and other fluids such as lymph that happens outside of the cells

Question 5

Intracellular fluid

Answer 5

the fluid inside the cells

Question 6

ECF and ICF

Answer 6

-there is a constant exchange of gasses and other materials between them. - Volume and composition of the ECF must remain stable for these exchanges to happen.

Question 7

Urinary system

Answer 7

is responsible for maintaining relatively stable conditions in the ECF.

Question 8

How does the body gain water?

Answer 8

from food and metabolic processes. Absorption of water from liquids and solid foods happens in the gastrointestinal tract. Metabolism of nutrients yields water as a byproduct.

Question 9

where does the body lose water?

Answer 9

in feces, urine by excretion, sweat, and by evaporation. from the lungs and skin.

Question 10

Urinary excretion

Answer 10

the production of urine; the body exerts most control over this

Question 11

Where is the least amount of water lost?

Answer 11

in feces

Question 12

How do solutes enter extracellular fluid?

Answer 12

from food,metabolism, and other ways. Solutes enter the body when nutrients and mineral ions are absorbed from the GI tract. Living cells secrete substances into tissue fluid and blood. The respiratory system brings oxygen into the blood; respiring cells add carbon dioxide.

Question 13

How do solutes leave the ECF?

Answer 13

by urinary excretion, in sweat and during breathing

Question 14

Respiratory exhalation

Answer 14

rids the body of carbon dioxide; all other major wastes of metabolism leave in urine.

Question 15

Uric acids

Answer 15

are formed in reactions that degrade nucleic acids; too much uric acid in the ECF crystallizes in joints, causing gout.

Question 16

Ammonia

Answer 16

formed when amino groups are removed from amino acids ; it is turned into urea in the liver and either reabsorbed or excreted.

Question 17

Which substances do the kidneys filter?

Answer 17

they filter a variety of substances from the blood including nitrogen, sodium, potassium, and calcium.

Question 18

Electrolytes

Answer 18

Sodium potassium and calcium are called these because a solution in which these are dissolved in will carry an electric current

Question 19

amount of water that enters the kidneys which is excreted?

Answer 19

1% of water that enters the kidneys is excreted in urine; most is returned to the blood

Question 20

Kidney

Answer 20

a bean shaped organ that is about the size of a rolled up pair of socks. A kidney has several internal lobes; an outer cortex wraps around the central medulla. The whole kidney is wrapped in a coat of connective tissue called the renal capsule. The central cavity of the kidney is called the renal pelvis.

Question 21

Functions of the kidney:

Answer 21

• produce erythropoietin, which stimulates production of red blood cells. - aid in calcium absorption from food.
• kidneys make renin, an enzyme that helps regulate blood pressure. Their main function is to remove metabolic wastes and maintain fluid balance.

Question 22

What else does the urinary system consist of ?

Answer 22

tube like ureters that carry urine to the urinary bladder for storage until urination; urine leaves the bladder through the urethra.

Question 23

Nephrons

Answer 23

Each lobe of the kidney contains blood vessels and over a million of these thin tubes which filter water and solutes from the blood

Question 24

Glomerulus

Answer 24

The wall of nephron balloons around a cluster of blood capillaries

Question 25

Bowman’s capsule

Answer 25

the balloon

Question 26

winding tubule

Answer 26

the rest of the nephron

Question 27

cycle of the nephron

Answer 27

filtrate from the bowmans capsule enters the proximal tubule, passes through the loop of Henle and into the distal tubule, and finally empties into a collecting duct.

Question 28

nephron absorption

Answer 28

some parts of the nephron allow absorption of water and solutes , other parts dont.

Question 29

Special vessels

Answer 29

transport blood to, in, and away from nephrons

Question 30

Afferent arteriole

Answer 30

delivers blood to each nephron where it enters the glomerulus for filtration; the glomerular capillaries are much more permeable than other capillaries.

Question 31

Glomerular capillaries

Answer 31

merge from an efferent arteriole.

Question 32

The efferent arteriole

Answer 32

splits to form the peritubular capillaries which eventually carries filtered blood into venules and out of kidneys

Question 33

Filtration

Answer 33

removes a large amount of fluid and solutes from the blood. blood pressure forces filtrate out of the glomerular capillaries into the Bowman’s capsule then into the proximal tube. Blood cells, proteins, and other large solutes cannot pass into the capsule; water, glucose, sodium, and urea, however are forced out of the blood.

Question 34

Reabsorption

Answer 34

returns useful substances to the blood and takes place across the walls of the proximal tubes. Water, glucose , and salt diffuse through the tubule wall; active transport moves glucose and sodium ions into the tissue fluid. Negatively charged ions follow the sodium into the tissues; water also follows. Solutes are actively transported from the tissues to the peritubular capillaries, water follows and reabsorption is complete. Any remaining solutes and water in the tubules become part of urine.

Question 35

Secretion

Answer 35

rids the body of excess hydrogen ions and other substances. During secretion urea excess hydrogen ions and potassium ions are returned to the nephrons to add to forming urine. This maintains the body’s acid base balance and rids the body of drugs , uric acid, hemoglobin breakdown products, and other wastes.

Question 36

Internal Urethral sphincter (involuntary control)

Answer 36

regulates urine flow from the bladder into the urethra during urination

Question 37

External Urethra sphincter (voluntary control)

Answer 37

opens to void urine from the body

Question 38

How much does the volume of blood fluids vary?

Answer 38

not much because because the kidneys make adjustments to keep the volume of extracellular fluid and blood in particular in a normal range.

Question 39

what happens as urine forms

Answer 39

Water follows salt. The loop of henle pulls more water and salts from the filtrate to return it to the body. The descending part of the loop sits in salty tissue fluid ; water is drawn out of the tube to be reabsorbed. The salt concentration of the remaining fluid in the loop rises until it matches the concentration of the surrounding tissues. In the ascending limb of the loop, water is inhibited from passing through the wall of the loop, but sodium is actively transported out of the loop.

Question 40

What continues to be removed?

Answer 40

salt in the distal tube , but not water; as salt leaves the filtrate, salt gradients become steep, driving reabsorption of solutes into the peritubular capillaries. Urea helps boost the gradient by diffusion out of the collecting duct, taking water with it.

Question 41

Hormones

Answer 41

control whether kidneys make urine that is concentrated or dilute.

Question 42

Antidiuretic horomone

Answer 42

is secreted by the brain in response to a decrease in extracellular fluid; ADH causes the distal tubes and collecting ducts to become permeable to water, which moves back into the blood capillaries.

Question 43

Decreases in volume of extracellular fluid

Answer 43

is sensed by cells in the efferent arterioles; these cells, part of the juxtaglomerular apparatus, release renin.

Question 44

What does renin stimulate?

Answer 44

production of angiotensin I, which is converted to angiotensin II.

Question 45

Angiotensin II

Answer 45

stimulates the adrenal cortex of the kidney to make aldosterone, which causes cells of the distal tubules and collecting ducts to increase reabsorption of salts.

Question 46

diuretics

Answer 46

substances that promote water loss ex: caffeine and alcohol

Question 47

A thirst center

Answer 47

monitors sodium. When solute concentration in the extracellular fluid rises, the amount of saliva produced by the salivary glands drops; a dry mouth stimulates the thirst center of the brain. Stimulation of the thirst center and release of ADH cause liquid seeking behavior.

Question 48

The body’s acid base balance

Answer 48

the relative amounts of acidic and basic substances in extracellular fluid, is maintained in part by the kidneys.

Question 49

How to kidneys maintain acid base balance?

Answer 49

by controlling the levels of bicarbonate in the blood. When the blood is too acidic, water and carbon dioxide combine in cells in the wall of the nephron tubules to give rise to bicarbonate and H+. The bicarbonate enters the peritubular capillaries and from there it enters the blood to neutralize acid. The H+ in the tubules enters the filtrate to combine with phosphate, ammonia, or bicarbonate to be excreted.

Question 50

What happens if the blood is too alkaline?

Answer 50

less bicarbonate is reabsorbed into the blood

Question 51

What happens once the blood is filtered?

Answer 51

Many other substances end up in urine; traces of drugs; excess glucose which is a sign of diabetes; pus, a sign of infection; and even blood, a sign of infection, cancer, or injury.

Question 52

Kidney Stones

Answer 52

deposits of uric acid , calcium salts, and other substances that have settled out of urine and collected in the renal pelvis. Small stones can pass during urination but larger ones can inhibit urination.

Question 53

Lithotripsy

Answer 53

uses sound waves to fragment the stones so they can pass out in the urine

Question 54

What can inflammation of bladders or kidneys result in?

Answer 54

infections to the urinary tract

Question 55

nephritis

Answer 55

general inflammation of the kidneys and can be severe enough to limit function

Question 56

Poly-cystic Kidney disease

Answer 56

an inherited disorder in which cysts form in the kidneys and gradually destroy normal tissue

Question 57

Glomerulonephritis

Answer 57

describes a variety of disorders that disrupt the flow of blood through the glomeruli of the kidneys.

Question 58

Dialysis

Answer 58

refers to the exchange of substances across a membrane between solutions of differing compositions

Question 59

Hemo dialysis

Answer 59

a machine is connected to an artery or vein, blood enters the tubes of the machine, and materials are removed from the blood before it is returned to the body.