excretion in humans

Question 1

where is carbon dioxide excreted through and dissolved in?

Answer 1

• Excreted through the lungs and dissolved in the blood plasma

Question 2

how is urine excreted?

Answer 2

• Urine passes from the kidneys, to the ureters and to the bladder where it is stored temporarily
  
  • When the bladder becomes full, the urethra carries the urine from the bladder to outside the body

Question 3

what is urine composed of?

Answer 3

• Composed of urea, excess water and ions excreted by the kidneys

Question 4

the liver (excretion in humans)

Answer 4

• Assists the body in taking up amino acids for cellular use
  
  • The liver can convert amino acids into fibrinogen and other plasma proteins
• Breaking down excess amino acids
• Excess amino acids are converted into urea in the liver (deamination)

Question 5

kidney is composed of:

Answer 5

cortex
renal vein
renal artery
medulla
ureter

Question 6

renal cortex function

Answer 6

outer part where blood is filtered and some selective reabsorption happens

Question 7

medulla function

Answer 7

inner part where some selective reabsorption happens and fluid is collected to form urine

Question 8

ureter function

Answer 8

carries urine to the bladder

Question 9

the nephron

Answer 9

• Main functional unit of the kidney
• Filters the blood - separating waste and returning substances that are needed back to the bloodstream
• Consists of the glomerulus and the tubule

Question 10

the glomerulus (in the nephron which is in the kidney)

Answer 10

Glomerulus:
- Network of capillaries
- Place where blood is filtered under pressure (called ultrafiltration)
- Water, glucose and ions leave the capillaries and enter the tubule. Protein molecules are too big so they stay in the blood.

Question 11

the tubule (in the nephron which is in the kidney)

Answer 11

Tubule:
- Where selective reabsorption of substances occurs
- Substances such as:
- All of the glucose
- Most of the water
- Some ions