The Excretory System

Question 1

The waste products released by the large intestine are: [__ __] (by egestion) and [__] (by excretion).

Answer 1

undigested cellulose - bilirubin

Question 2

[__] is the removal of undigested food material from the body.
[__] is the removal of metabolic waste products produced by the cells.

Answer 2

Egestion - Excretion

Question 3

The nephron performs three main functions. What are these functions and identify the site of each?
❥ Ultrafiltration occurs at the [__].
❥ Selective reabsorption occurs at the [__ __ __].
❥ Osmoregulation occurs at the [__ __].

Answer 3

❥ glomerulus
❥ proximal convoluted tubules
❥ collecting ducts

Question 4

Describe what happens during ultrafiltration.
❥ The afferent arteriole has a [__] diameter than the efferent arteriole and this results in the blood flowing through the [__] having a high pressure.
❥ The small pores in the walls of [__ __] and the increased pressure forces up to [__ __] of the blood plasma to leak out of the glomerulus and fill up the Bowman’s / renal capsule.
❥ The portion of the plasma that has entered the Bowman’s / renal capsule is the [__] and contains water with some glucose, mineral salts, [__ __] and urea.
❥ It does not contain blood cells and [__] as these are too large to pass out of the [__].

Answer 4

❥ larger - glomerulus
❥ glomerular capillaries - one fifth
❥ filtrate - amino acids
❥ proteins - glomerulus

Question 5

❥ Selective reabsorption means only some components of the [__] are brought back into the [__].
❥ The [__] reabsorbs from the filtrate all the glucose and [__ __], most water and some salts to maintain [__].

Answer 5

❥ filtrate - blood

❥ kidney - amino acids - homeostasis

Question 6

Glucose and amino acids are reabsorbed by [__ __].

Answer 6

active transport

Question 7

❥ Osmoregulation is the maintenance of [__ __].
❥ It occurs in the [__ __].
❥ This process is under the control of the [___] in the brain and a hormone called [__ __] or ADH.

Answer 7

❥ water balance
❥ collecting ducts
❥ hypothalamus - antidiuretic hormone

Question 8

When is ADH released?
❥ The blood concentration is monitored by the [___].
❥ The hypothalamus stimulates the [__ __] to release ADH when blood water potential is low such as, in case of excessive sweating in hot weather.

Answer 8

❥ hypothalamus

❥ pituitary gland

Question 9

What is the effect of the anti-diuretic hormone?
❥ ADH hormone is transported in the [__] of the blood from the pituitary gland to the [__] of the kidney.
❥ ADH increases the [___] of the membrane of the cells lining the collecting ducts so more water is [___] back into the body.
❥ A [__] quantity /volume of very concentrated urine is produced.

Answer 9

❥ plasma - nephrons
❥ permeability - reabsorbed
❥ small

Question 10

ADH has an effect on the collecting ducts making them more [___].

Answer 10

permeable

Question 11

❥ When a person is hydrated, a large volume of [__ __] will be produced to maintain the proper concentration of solutes in bodily fluids and to avoid the dilution of bodily fluids.
❥ Conversely, if an individual is dehydrated and needs water to maintain the proper concentration of solutes in bodily fluids, a smaller volume of more [__ __] will be produced to reduce further water loss from the body.

Answer 11

❥ dilute urine

❥ concentrated urine

Question 12

Describe the process of deamination.
❥ Excess amino acids are [__ __] in the body, they are carried to the [__] where they are [___] by the removal of their amine NH2 group.
❥ This results in the production of [__ __] which is converted into urea and released into the blood to be filtered out by the kidneys and excreted in the urine.
❥ The remaining acid group is converted into [__], then into glucose and used for [__ __] as a source of energy.

Answer 12

❥ not stored - liver - deaminated
❥ toxic ammonia
❥ glycogen - cellular respiration

Question 13

Kidney dialysis is the process by which urea, excess salts, excess water, and other substances are [__ __ __ __] of a patient suffering from [__ __] using a special machine called a [__ __] or a kidney machine.
 Dialysis works on the [__ __ __] of solutes across the selectively permeable membrane.

Answer 13

removed from the blood - kidney failure - dialysis unit

principle of diffusion

Question 14

❥ A dialysis or kidney machine consists of a length of [__ __ __] through which the person’s blood is pumped.
❥ The tubing is made of [__] with small pores allowing small molecules to pass by [__].
❥ The tubing is long and narrow to provide a large surface area for [__ __].

Answer 14

❥ selectively permeable tubing
❥ cellulose - diffusion
❥ adequate diffusion

Question 15

Blood cells and proteins are [__ __] but urea, glucose, salts and some unwanted substances are small enough to pass through the [__ __].

Answer 15

too large - dialysis tubing

Question 16

The bathing solution is [__ __]. Fresh dialysis fluid should contain [__ __]. It contains the same [___] of glucose and salts as healthy blood to prevent the loss of these substances from the patient’s blood.

Answer 16

dialysis fluid - no urea - concentration

Question 17

What two precautions must be taken while carrying out dialysis?
❥ The dialysis fluid must be [__ __] to maintain a diffusion gradient for urea to [__ __] of the patient’s blood.
❥ The bathing solution is maintained at [__ __].

Answer 17

❥ changed frequently - diffuse out

❥ body temperature

Question 18

Urea and other wastes diffuse out of the patient’s blood through the [__ __] into
the dialysis fluid by [__].

Answer 18

dialysis tubing - diffusion

Question 19

Will glucose and salts be lost from the patient’s blood during dialysis treatment?

Answer 19

No, glucose and salts will not be lost from the patient’s blood as the dialysis fluid has the same concentration of glucose and salts as the patient’s blood and therefore there is no concentration gradient

Question 20

An alternative to dialysis is kidney transplant. Identify a problem that may result due to a kidney transplant.
❥ The recipient’s immune system attacks the transplant because it is [__] to the body. This is known as [__ __].
❥ To minimize postsurgical complications in a kidney transplant, the donor and the recipient must be [__].
❥ Kidney transplant is [__] due to the shortage of kidneys.

Answer 20

❥ foreign - kidney rejection
❥ compatible
❥ limited

Question 21

An alternative to dialysis is kidney transplant. What are the advantages of a kidney transplant over dialysis?
❥ It is [__ __] in the long run than kidney dialysis treatments, which need to be performed for the rest of the patient’s life.
❥ There are no [__ __].
❥ The patient is [__] cured from his disease if the transplant is successful.
❥ The patient can lead a normal life without returning to the hospital every few days.

Answer 21

❥ less expensive
❥ dietary restrictions
❥ permanently