Urinary System

Question 1

The urinary system consists of:

Answer 1

Kidneys
Cortex - outer layer of the kidney
Medulla - area inside of the cortex
Renal pelvis - area where the kidney joins the ureter

Ureters

Tubes that conduct urine from the kidneys to the bladder

Bladder

Urethra
Tube that carries urine from the bladder to the exterior of the body

Question 2

Kidneys

Answer 2

Cortex - outer layer of the kidney
Medulla - area inside of the cortex
Renal pelvis - area where the kidney joins the ureter

Question 3

Ureters

Answer 3

Tubes that conduct urine from the kidneys to the bladder

Question 4

Urethra

Answer 4

Tube that carries urine from the bladder to the exterior of the body

Question 5

The kidneys play a crucial role in

Answer 5

Waste removal/production of urine
Maintaining water balance
Balancing blood pH
Balancing blood pressure

Question 6

The Nephron

Answer 6

It is the functional unit of the kidney

There are about 1 million contained within the kidneys

Question 7

The Nephron

Afferent arterioles -

Answer 7

small branches that carry blood to the glomerulus

Question 8

The Nephron

Glomerulus -

Answer 8

high-pressure capillary bed that is the site of filtration

Question 9

The Nephron

Efferent arterioles -

Answer 9

small branches that carry blood away from the glomerulus to a capillary net

Question 10

The Nephron

Peritubular capillaries -

Answer 10

network of small blood vessels that surround the nephron

Reabsorbs solute from the nephron into the blood and secretes solute from the blood into the nephron

Question 11

The Nephron

Bowman’s capsule -

Answer 11

Cuplike structure that surrounds the glomerulus

Question 12

The Nephron

Proximal tubule -

Answer 12

section of the nephron joining the Bowman’s capsule with the loop of Henle

Question 13

The Nephron

Loop of Henle -

Answer 13

carries filtrate from the proximal tubule to the distal tubule

Question 14

The Nephron

Distal tubule -

Answer 14

conducts urine from the loop of Henle to the collecting duct

Question 15

The Nephron

Collecting duct -

Answer 15

tube that carries urine from nephrons to the pelvis of a kidney

Question 16

Filtration

Answer 16

movement of fluids from the blood into the Bowman’s capsule (not selective) *ask

Question 17

Reabsorption

Answer 17

the transfer of essential solutes and water from the nephron back into the blood (active transport/selective)

Question 18

Secretion

Answer 18

the movement of materials from the blood back into the nephron (active transport/selective)

Question 19

Steps in formation of urine

Answer 19

Filtration - movement of fluids from the blood into the Bowman’s capsule (not selective)

Reabsorption - the transfer of essential solutes and water from the nephron back into the blood (active transport/selective)

Secretion - the movement of materials from the blood back into the nephron (active transport/selective)

Question 20

Filtration

Answer 20

As blood moves from the afferent arteriole into the glomerulus (capillary bed), dissolved solutes move from the walls of the glomerulus into the Bowman’s capsule due to high pressure
Not all materials leave the blood and enter the capsule

Plasma protein, blood cells, and platelets are too large to move through the walls of the glomerulus.
Smaller molecules pass through the cell membrane and enter the nephron

Question 21

Reabsorption

Answer 21

Why filter out materials, only to reabsorb them again
120 ml of filtrate enters the nephron per min and only forms about 1 ml of urine bc the remaining fluids are reabsorbed
If reabsorption did not occur, you would be peeing 120 ml of urine every minute

Question 22

1. Glomerulus and Bowman’s capsule

Description of Process

Answer 22

Filtration of water and dissolved solutes occurs as blood is forced through walls of glomerulus into Bowman’s capsule by fluid pressure in capillaries

Question 23

1. Glomerulus and Bowman’s capsule

Substance Transported

Answer 23

Sodium ions (Na+) 
Chloride ions (Cl-) 
Water (H2O) 
Hydrogen ions (H+)
Glucose 
Amino acids 
Vitamins
Minerals 
Urea 
Uric acid

Question 24

2. Proximal tubule

Description of Process

Answer 24

Selective reabsorption of nutrients from filtrate back into blood by active and passive transport
Within proximal tubule, pH is controlled by secretion of H+ ion and reabsorption of bicarbonate ions

Question 25

2. Proximal tubule | Substance Transported

Answer 25

``` Bicarbonate ions (HCO3-) Salt (NaCl) Water (H2O) Potassium ions (K+) Hydrogen ions (H+) Ammonia (NH3) Glucose Amino acids Vitamins urea ```

Question 26

3. Descending limb of loop of Henle Description of Process

Answer 26

Permeable to water Resulting in loss of water from filtrate by osmosis Salt becomes concentrated in filtrate as descending limb penetrates inner medulla of kidney

Question 27

3. Descending limb of loop of Henle Substance Transported

Answer 27

Water (H2O)

Question 28

4. Ascending limb of loop of Henle Description of Process

Answer 28

Thin segment is permeable to salt Resulting in diffusion of salt out of ascending limb Salt continues to pass from filtrate to interstitial fluid in thick segment of ascending limb

Question 29

4. Ascending limb of loop of Henle Substance Transported

Answer 29

Salt (NaCl)

Question 30

5. Distal tubule Description of Process

Answer 30

Selective reabsorption of nutrients from blood into nephron by active transport Help regulate potassium and salt conc’n of body fluids

Question 31

5. Distal tubule Substance Transported

Answer 31

``` Sodium ions (Na+) Potassium ions (K+) Bicarbonate ions (HCO3-) Water (H2O) Hydrogen ions (H+) Uric acid Ammonia ```

Question 32

6. Collecting duct Description of Process

Answer 32

Urine formation

Question 33

6. Collecting duct Substance Transported

Answer 33

``` Salt (NaCl) Water (H2O) Urea Uric acid Minerals ```

Question 34

Secretion

Answer 34

Active transport of K+, N-molecules, H+ into nephron | Occurs in the Distal Tubule

Question 35

Antidiuretic hormone (ADH)

Answer 35

a hormone that causes the kidneys to increase water reabsorption, regulating osmotic pressure of body fluids and fluid volume

Question 36

When ADH is released

Answer 36

more concentrated urine is produced, thereby conserving body water

Question 37

Osmoreceptors

Answer 37

specialized nerve cells in the hypothalamus that detect changes in the osmotic pressure of the blood and surrounding extracellular fluids (ECF)

Question 38

Decrease in water intake (or increase water loss)

Answer 38

blood solutes become more concentrated → increases blood osmotic pressure

Question 39

Osmotic pressure

Answer 39

conc’n of solute in blood

Question 40

regulating adh, water

Answer 40

So water moves into the bloodstream, causing cells of the hypothalamus to shrink A nerve message is sent, signalling the release of ADH By reabsorbing more water, the kidneys produce a more concentrated urine, preventing the osmotic pressure of the body fluids from increasing any further

Question 41

ADH and the Nephron (3)

Answer 41

Without ADH, the rest of the tubule remains impermeable to water. But continues to actively transport Na+ ion from the tubules ADH makes the upper part of the distal tubule and collecting duct permeable to water When permeable, the high conc’n of NaCl in the intercellular space creates an osmotic pressure that draws water from the upper section of the distal tubule and collecting duct As water passes from nephron to intercellular spaces and the blood, the urine becomes more concentrated

Question 42

Kidneys and Blood Pressure

Answer 42

Kidneys regular BP by adjusting blood volumes

Question 43

Aldosterone -

Answer 43

a hormone that increases Na+ reabsorption from the distal tubule and collecting duct

Question 44

pH of body is b/w

Answer 44

7.3 and 7.5

Question 45

During cellular respiration, cells produce CO2 which forms

Answer 45

carbonic acid. Carbonic acid and other excess acids ionize to produce H+ ions The buildup of H+ ions lowers the pH

Question 46

An acid-base balance is maintained by buffer systems that absorb excess H+ ions or ions that act as bases

Answer 46

Excess H+ ions are buffered by bicarbonate ions in the blood, carbonic acid is produced Carbonic acid breaks down to form carbon dioxide and water CO2 is transported to lungs Bicarbonate ions (HCO3-) eliminate the excess H+ ions, preventing a change in pH

Question 47

Diabetes Mellitus CAUSE

Answer 47

inadequate secretion of insulin from islet cells in the pancreas

Question 48

Diabetes Mellitus | EFFECT:

Answer 48

without insulin, blood sugar levels rise Excess sugar remains in the nephron and provides an osmotic pressure that opposes the osmotic pressure created Water remains in the nephron and is lost with the urine Releases large volumes of urine = thirsty The water lost with the excreted sugar must be replenished

Question 49

Diabetes Insipidus CAUSE

Answer 49

destruction of ADH-producing cells of the hypothalamus | Or destruction of the nerve tracts leading from the hypothalamus to the pituitary gland

Question 50

Diabetes Insipidus EFFECT

Answer 50

without ADH to regulate water reabsorption, urine output increases dramatically Must drink large quantities of water

Question 51

Bright’s Disease CAUSE

Answer 51

AKA. Nephritis Inflammation of nephrons AFFECTS: Tiny blood vessels of the glomerulus CAUSE: toxins produced by invading microbes

Question 52

Bright’s Disease

Answer 52

EFFECT: destroy the tiny blood vessels, altering the permeability of the nephron Proteins and other large molecules are able to pass into the nephron Proteins remain in the nephron and create an osmotic pressure that draws water into the nephron Increases the output of urine

Question 53

Kidney Stones | CAUSE:

Answer 53

the precipitation of mineral solute from the blood

Question 54

Kidney Stones CATEGORIES:

Answer 54

Alkaline or Acid Stones | Sharp-sided stones can lodge in the renal pelvis or move into the narrow ureter

Question 55

Kidney Stones EFFECT:

Answer 55

delicate tissues are torn as the stones move to the bladder | Can move to the excretory passage and lodge in the urethra, causing pain as it moves