Urinary System

Question 1

What is in the urinary system involved in regulating?

Answer 1

The composition od the blood by removing wastes, the volume of blood by removing or retaining water, the pH of the blood by removing H+ ions and blood pressure.

Question 2

What does the mammalian urinary system consist of?

Answer 2

Left and right kidneys, left and right ureters, bladder, urethra, renal arteries and veins.

Question 3

What do kidneys do?

Answer 3

They carry out the work of the urinary system, including excretion of wastes from the blood. They also regulate blood volume, blood pressure and release hormones.

Question 4

What are the glands that sit on each kidney called?

Answer 4

Adrenal glands.

Question 5

What are the tubes that connect the kidneys to the bladder called?

Answer 5

Ureters.

Question 6

What is the tube that excretes urine from the bladder called?

Answer 6

Urethra.

Question 7

What is the muscle that holds the urethra shut?

Answer 7

The sphincter muscle.

Question 8

What are nephrons?

Answer 8

Microscopic units that filter blood and remove wastes from it. The fluid excreted by the kidneys is called urine. They are 3cm long, one end is closed and the other opens into a collecting duct. The closed end forms the nephron capsule. The rest of the tubule is coiled and closely associated with the blood capillary network.

Question 9

What is the outer capsule of the kidney called?

Answer 9

Renal capsule.

Question 10

What is the inner centre of the kidney called?

Answer 10

Renal pelvis.

Question 11

What is the outer layer inside the kidney called?

Answer 11

Cortex.

Question 12

What are the petal-shaped bits in the internal centre of the kidney called?

Answer 12

Medulla.

Question 13

How is urine produced?

Answer 13

Filtration under pressure in nephron capsule, selective reabsorption in tubules, active secretion into tubules.

Question 14

How do nephrons work?

Answer 14

Blood is brought to the nephron capsule for filtration. Filtrate is formed which moves along the tubule. Much of the water and other useful substaces in the filtrate are reabsorbed back into the blood capillary network. Certain ions and toxins may be actively secreted from the blood into the filtrate. The filtrate is gradually transformed into urine as it moves along the tubule.

Question 15

What substances are filtered from the blood into the nephron capsule?

Answer 15

Water, glucose, amino acids, urea, uric acid, ions.

Question 16

What substances are reabsorbed from the nephron tubule?

Answer 16

Water, glucose, amino acids.

Question 17

What substances are secreted into the nephron tubule?

Answer 17

Hydrogen ions, drugs.

Question 18

Are proteins and glucose found in normal urine?

Answer 18

No.

Question 19

What does normal urine consist of?

Answer 19

95% water, nitrogenous waste products of protein metabolism (e.g. urea, uric acid and creatinine), ions (Na+, K+, H+, HCO3-, Cl-) and some hormones.

Question 20

What happens when the bladder is full?

Answer 20

The stretch of the bladder wall signals to the animal to empty the bladder.

Question 21

What does urinalysis look at?

Answer 21

It looks at appearance of the urine so things like colour and turbidity/cloudiness. Urine may have a slightly cloudy appearance due to the pressence of mucus. Mucus is a normal constituent of horses’ urine giving it a charactistic cloudy appearance. Specific gravity - use a Refractomenter. Muiltisk- test for pH and the presence of glucose, protein, ketones, blood, bilirubin. Microscope - look for casts.

Question 22

How does the urinary system in a bird work?

Answer 22

Birds have kidneys (that are composed of many nephrons), which filter the blood and produce insoluble uric acid as their main waste, which is excreted in the form of a paste. This is a water-conserving and weight saving adaption. With no urinary bladder, bird’s urine empty from the ureters into the cloaca where it mixes with the faeces and is passed as a semi-solid mixture.

Question 23

Where is 2/3 of the body fluid’s found? How about the 1/3?

Answer 23

2/3 are found within the cells (ICF) and 1/3 is found outside the cells (ECF). Some extracellular fluids include tissue fluid, plasma, lymph, CSF (cerebrospinal fluid), ear and eye fluids, secretions in the gut (e.g. saliva, gastric juice), sweat, urine sodium and chlorine ions.

Question 24

What are the main sources of water in the body?

Answer 24

Ingestion (fluids and moist food), metabolism (fats and carbohydrates).

Question 25

What are the four main routes for water loss? Which one is the only route that can be regulated to compensate for changes in water?

Answer 25

Kidneys from urine, digestive tract from faeces, respiratory tract from exhaled air and skin from sweat. Kidneys can can regulate fluid lost in urine.

Question 26

What are some abnormal losses of water.

Answer 26

Excessive amounts of dilute urine, vomiting, diarrhoea, excessive panting, profuse sweating, burns and haemorrhaging.

Question 27

How much water in the nephron is reabsorbed?

Answer 27

Over 90% of water is reabsorbed.

Question 28

Which hormone controls the amount of water that is reabsorbed? Which gland produces this?

Answer 28

Antidiuretic hormone (ADH). The posterior pituitary gland.

Question 29

How does the body conserve water during dehydration?

Answer 29

When there is fluid loss, the pituitary gland releases ADH and targets the kidneys. The kidneys conserve water by reabsorbing it.

Question 30

What is the role of thirst in a dehydrated animal?

Answer 30

It makes a dehydrated animal try to find some water.