Nervous System Control of Excretion/ Role of Liver, Lungs, Skin

What controls the release of urine from the urethra ?i i

Two rings of muscle .i i

One ring is in___ and the other is ___ .i i

Involuntary, voluntary .i i

The ring of muscle under the control of the brain relaxes depending on what ?i i

The amount of urine in the bladder .i i

What happens to both rings during urination ?i i

Both rings relax and the walls of the bladder contract .i i

What happens if the supply of stored glycogen in the liver is gone ?i i

The liver changes amino acids into glucose molecules .i i

What is the process of converting amino acids into glucose molecules called ?i i

Deamination .i i

What is deamination ?i i

The removal of an amino ground from an amino acid .i i

What happens to the amino group after deamination ?i i

Ammonia is formed .i i

What is ammonia ?i i

Ammonia is a highly toxic waste product .i i

What does the liver do with the ammonia ?i i

The liver combines the ammonia with carbon dioxide to form a less toxic waste called urea .i i

What happens to the urea and ammonia ?i i

They are released into the blood and will be removed by the kidneys .i i

What is the role of the lungs in excretion (2) ?i i

The lungs remove carbon dioxide and some water vapour .i i

What is the role of the skin in excretion (3) ?i i

Perspiration removes excess water, salts, and some urea .i i