Urinary system

Question 1

What does the urinary system consist of?

Answer 1

-two kidneys
-two ureters
-one urinary bladder
-one urethra

Question 2

What is the main function of the kidneys?

Answer 2

to filter the blood and return most of the water and solutes to the blood, and anything remaining is passed out as urine

Question 3

What are the other functions of the kidney that helps to maintain homeostasis?

Answer 3

-regulation of ion levels in the blood
-regulation of blood volume and blood pressure
-regulation of blood pH
-production of hormones
-excretion of wastes

Question 4

What are the structures of the kidneys?

Answer 4

-nephron
-renal cortex
-renal medulla
-renal column
-renal pyramid
-renal papilla
-renal lobe
-renal artery
-renal vein

Question 5

What are the functions of the nephron?

Answer 5

to produce urine, nephrons and collecting ducts perform three basic processes: glomerular filtration, tubular reabsorption, and tubular secretion

Question 6

What is glomerular filtration?

Answer 6

-the first step to produce urine
-blood pressure forces water and most solutes in blood plasma across the wall of glomerular capillaries

Question 7

What is tubular reabsorption?

Answer 7

-returning most of the filtered water and many of the filtered solutes to the blood including glucose, amino acids, and ions that the body needs
-epithelial cells run along the renal tubules and collecting ducts to carry out this process

Question 8

What is tubular secretion?

Answer 8

-the tubule and duct removes substances, such as wastes, drugs, and excess ions, from blood in the peritubular capillaries and transport them into the fluid in the renal tubules

Question 9

What is the major hormone that regulates water reabsorption?

Answer 9

antidiuretic hormone (ADH) via negative feedback

Question 10

What are the functions of angiotensin ii?

Answer 10

-It enhances the reabsorption of sodium and chloride
-angiotensin ii also stimulates the adrenal cortex to release aldosterone which stimulates the collecting ducts to reabsorb more sodium and chloride, and secrete more potassium

Question 11

What does Atrial natriuretic peptide (ANP) do?

Answer 11

inhibits reabsorption of sodium and chloride and water by the renal tubules, reducing blood volume

Question 12

Where does urine produced by the nephrons drain to?

Answer 12

-into the minor calyces, which join to become major calyces that unite to form the renal pelvis
-from the renal pelvis of the right and left kidney to the two ureters, and then into the bladder, where urine is discharged from the body through the urethra

Question 13

What are the three layers that the ureter consists of?

Answer 13

-transitional epithelium in the inside (mucosa)
-smooth muscle in the middle
-areolar connective tissue on the outside

Question 14

What is the urinary bladder and what is its function?

Answer 14

-a hollow muscular organ in the pelvic cavity posterior to the pubic symphysis
-store urine prior to micturition

Question 15

What are the physical characteristics of normal urine?

Answer 15

-volume= 1-2 litres in 24hrs
-colour= yellow/amber, but varies with concentration and diet
-turbidity= transparent when freshly voided but becomes cloudy after a while
-odor= mildly aromatic
-pH= ranges between pH 4.6 and 8.0, averaging 6.0

Question 16

What are some of the abnormal constituents in urine?

Answer 16

-albumin
-glucose
-red blood cells
-white blood cells
-ketone bodies
-billirubin
-urobilinogen
-casts
-microbes

Question 17

How does the ureters work?

Answer 17

-transports urine from the kidneys to urinary bladder, and as it fills it expands and compresses the ureters which prevents the backflow of urine

Question 18

What are the parts of the urinary bladder?

Answer 18

-Detrusor muscle- stretches when the urinary bladder fills and contracts to push urine out

-urethra- leads from urinary bladder

-rugae- allow bladder to expand as it fills

-peritoneum- holds bladder in place

-internal urethral sphincter- involuntary smooth muscle to open and close urethra

-external urethral sphincter- voluntary skeletal muscle that opens and closes urethra

-external urethral orifice- opening of urethra to outside

Question 19

What is the difference between acids and bases?

Answer 19

-Acids release highly reactive hydrogen ions
-Bases release highly reactive hydroxyl ions

Question 20

What is a neutralisation reaction?

Answer 20

acids and bases react to form water and a salt

Question 21

What is a salt?

Answer 21

easily dissociate into ions in the presence of water, vital to many life processes (electrolytes conduct electrical currents)

Question 22

Give examples of inorganic acid, base and salt

Answer 22

-Acid= HCL
-Base= KOH
-Salt= KCL

Question 23

What is the normal pH of blood?

Answer 23

7.35 to 7.45 pH

Question 24

What are buffer systems (examples) and what do they do?

Answer 24

-buffers are substances that act quickly to temporarily bind hydrogen ions, removing the highly reactive, excess hydrogen ions from solution but not the body
-e.g protein buffer system
-e.g carbonic acid-bicarbonate buffer system
-e.g phosphate buffer system

Question 25

Why is it important to keep the hydrogen ion level (pH) of body fluids in the appropriate range?

Answer 25

To maintain homeostasis

Question 26

Explain how breathing plays a role in maintaining the pH of body fluids?

Answer 26

-an increase in carbon dioxide in body fluids increases hydrogen ion concentration and thus lowers the pH making it more acidic, while a decrease in carbon dioxide raises the pH, making it more alkaline

Question 27

Explain how kidney excretion maintains pH?

Answer 27

-slowest mechanism but only way to eliminate most acids that form in the body
-cells of renal tubules secrete hydrogen ions, which then is excreted in urine

Question 28

What is acidosis?

Answer 28

-a systemic arterial blood pH below 7.35, causing depression of the central nervous system

Question 29

What is alkalosis?

Answer 29

-a systemic arterial blood pH above 7.45, causing over excitability of the central nervous system