10.6Chapter 10: Excretion in Humans
Chapter 10 Review: Excretion in Humans — Alhussan Biology - Stage 9 Revision Notes & Topical Questions
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Lesson summary
10.6 Chapter 10 Review: Excretion in Humans — Alhussan International Academy — Biology (Stages 7–9) notes: Revise the products and organs of excretion, kidney function, kidney failure, models and osmoregulation from Chapter 10.Excretion — the removal of metabolic waste and of sub…
- Renal artery
- Glomerulus
- Urine path
- Renal vein
- Precise terms
- Too little water
Section 1 of 7Excretion and its organs
Excretion
- Excretion the removal of metabolic waste and of substances in excess.
Lungs
- Lungs carbon dioxide leaves through the lungs.
Kidneys
- Kidneys urea, excess water and salts leave in urine.
Skin
- Skin it loses water, salts and a little urea in sweat.
Urea
- Urea it is produced in the liver from excess amino acids by deamination, in which the amino group is removed.
Egestion
- Egestion faeces are egested, not excreted.
Section 2 of 7The urinary system and nephron
The urinary system and nephron
Renal artery
- Renal artery it brings blood to each kidney, where the nephrons filter it.
Glomerulus
- Glomerulus high pressure forces water, glucose, salts and urea into the capsule, while proteins and blood cells stay in the blood.
Tubule
- Tubule all the glucose and as much water and salt as needed are reabsorbed.
Urine path
- Urine path the rest flows to the ureter, is stored in the bladder and passes out through the urethra.
Renal vein
- Renal vein it carries away blood that has less urea.
Precise terms
- Precise terms filtration is by size, reabsorption is selective, and urine is formed from what is left.
Section 3 of 7Water balance
1Too little water
- Too little water the pituitary gland releases more ADH, the kidneys reabsorb more water, and a small volume of concentrated urine is made.
2Too much water
- Too much water less ADH is released and a large volume of dilute urine is produced.
3Urine output after a drink
- Urine output after a drink it rises quickly, peaks and then returns to the normal rate as the extra water is removed.
4Freshwater fish
- Freshwater fish they excrete large amounts of dilute urine.
5Marine bony fish
- Marine bony fish they excrete small amounts of concentrated urine and remove salt through the gills.
6Adapted mammals
- Adapted mammals kidneys differ with the habitat, for example camels and kangaroo rats make concentrated urine and beavers make dilute urine.
Section 4 of 7Kidney failure and treatment
Effect
- Effect waste builds up in the blood.
Dialysis
- Dialysis blood passes along a partially permeable membrane with dialysis fluid on the other side.
- Urea diffuses out of the blood into the fluid.
- Glucose stays in the blood because the fluid already contains it.
Transplant
- Transplant it is a long-term solution but carries the risk of rejection and needs immunosuppressant drugs.
Section 5 of 7Models of the kidney
Purpose
- Purpose a model helps explain something that cannot easily be seen.
Evaluating
- Evaluating say what each part stands for and mention its limitations.
Section 6 of 7Key terms
| Term | Meaning |
|---|---|
| Excretion | Removal of metabolic waste from the body. |
| Deamination | Removal of the amino group from excess amino acids in the liver. |
| Filtration | Separation of small molecules from the blood by size. |
| Reabsorption | Selective return of useful substances to the blood. |
| ADH | A hormone that controls reabsorption of water in the kidneys. |
| Dialysis | Cleaning the blood with a machine in kidney failure. |
Section 7 of 7Exam technique
1
Mixing up excretion with egestion.
2
Saying urea is made in the kidney — it is made in the liver.
3
Stating that the kidney keeps urea — urea is filtered out and removed.
4
Writing that dialysis removes proteins from the blood.
Marked practiceQuizzes for this lesson
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