excretory system

Question 1

what is excretion

Answer 1

removal of the wastes of metabolism from the body is called excretion

Question 2

what parts of the body are involved in the processing and excretion of wastes

Answer 2

the lungs, the liver, the alimentary canal, sweat glands and the kidneys

Question 3

what are kidneys

Answer 3

kidneys are the principal excretory organs as they are responsible for maintaining material in bodily fluids.

Question 4

what do the kidneys excrete?

Answer 4

nitrogenous wastes urea (which is produced from the breakdown of amino acids in the liver), uric acids and creatinine are the most toxic wastes excreted by the kidneys.

Question 5

deamination + why does it occur?

Answer 5

deamination is the removal of the amino group (NH2) from amino acids so that the remaining part can form carbohydrates to be used for energy production that occurs in the liver with the aid of enzymes.

amino acid + oxygen → carbohydrate + ammonia
* carbohydrate → energy
* amine group → ammonia → urea + water

deamination occurs for use of proteins as they produce energy

Question 6

functions of the liver

Answer 6

• preparation of materials for excretion
• Detoxifies alcohol, other drugs
• Deactivates many hormones and converts them into a form thatcan be excreted by the kidneys
• Breaks down haemoglobin to produce bile pigments (passed outof the body with the faeces)

Question 7

skin: function + role in excretory system

Answer 7

Function: provide protective covering over surface of the bodyand to regulate body temperature

• sweat glands located in the low layers of the skin, duct carries sweat to follicle or to skin surface
• cells around the glands contract which squeeze the sweat to the surface of the skin

Question 8

kidney function

Answer 8

• removes waste from the blood
• regulates water content and the pH of blood

Question 9

renal artery

Answer 9

carries blood to kidney

Question 10

renal vein

Answer 10

carried blood away from kidneys

Question 11

medulla

Answer 11

inner part of kidney

Question 12

cortex

Answer 12

outer part of kidney

Question 13

renal pelvis

Answer 13

funnels urine into ureter

Question 14

nephrons

Answer 14

nephrons are the functional units of the kidney. there is around one million nephrons in each kidney.

Question 15

parts of the nephron (12)

Answer 15

• renal artery and renal vein
• afferent arteriole
• glomerulus
• bowman’s capsule
• efferent arteriole
• peritubular capillaries
• proximal convoluted tubule
• descending loop of henle
• ascending loop of henle
• distal convoluted tubule
• collecting tubule

Question 16

three major processes in the production of urine

Answer 16

• glomerular filtration
• selective tubular reabsorption
• tubular secretion

Question 17

glomerular filtration

Answer 17

This is the first step of the formation of urine. Blood is filtered in the renal capsule as the blood travels through the glomerulus. This filtrate is collected in the glomerular capsule.

Question 18

selective tubular reabsorption

Answer 18

Selective absorption of useful substances including water, glucose, amino acids and some ions occurs in the proximal convoluted tubule, the loop of Henle, the distal convoluted tubule and collecting duct.

Question 19

tubular secretion

Answer 19

Tubular Secretion moves substances such as drugs, potassium, creatinine and hydrogen ions from the blood to the urine in the distal convoluted tubule.

Question 20

where does urine go after moving to the collecting ducts?

Answer 20

urine then travels through the collecting ducts to the renal pelvis to the ureters. then urine travels to the bladder where it is stored then is excreted through the urethra.

Question 21

what is micturition?

Answer 21

process of excreting urine through urethra.

Question 22

what occurs in the collecting duct?

Answer 22

active reabsorption of water, depending on the body’s water needs

Question 23

what occurs in the renal corpuscle?

Answer 23

• filtration of blood from capillaries of glomerulus
• formation of filtrate in the glomerular capsule

Question 24

what occurs in the proximal convoluted tubule and the loop of henle?

Answer 24

• passive reabsorption of potassium, chloride and bicarbonate ions
• active reabsorption of glucose and sodium
• passive reabsorption of water by osmosis

Question 25

what occurs in the distal convoluted tubule

Answer 25

• active reabsorption of sodium ions
• active reabsorption of water, depending on body’s water needs
• secretion of hydrogen and potassium ions, creatinine and certain drugs such as penicillin

Question 26

how much of the filtrate is turned into urine?

Answer 26

only 1%

Question 27

concentration of urine

Answer 27

very high

Question 28

waste products in urine

Answer 28

urea, sulfates and phosphates, these are created as solution in the urine

Question 29

chemical components of urine

Answer 29

water (main component), sodium, chloride and other ions, proteins, glucose, urea, uric acid + creatinine

Question 30

kidney stone

Answer 30

when urine becomes too concentrated, solid crystals form

Question 31

kidney failure

Answer 31

occurs when the kidneys lose their ability to excrete wastes and control the level of fluid in the body

Question 32

peritoneal dialysis

Answer 32

dialysis occurring inside the body, using the peritoneum as the membrane across which wastes can be removed

Question 33

dialysis

Answer 33

method of removing wastes from the blood when kidney failure occurs.

Question 34

haemodialysis

Answer 34

passing the blood through an artificial kidney or dialysis machine

Question 35

liver disease

Answer 35

when the liver is not able to function effectively, it is hbavke to process toxins for elimination.
can be caused by infection, autoimmune problems, genetic disorders, cancer and lifestyle factors