Embarking on the exploration of excretion unveils the intricate mechanisms by which organisms rid themselves of toxins and metabolic byproducts. Excretion, a fundamental process in biology, ensures the body maintains internal balance by eliminating harmful substances like urea and carbon dioxide. From the kidneys’ meticulous filtration to the liver’s pivotal role in amino acid metabolism, each component of the excretory system plays a vital part in sustaining life. As we delve deeper into this biological phenomenon, we unravel the complexities of waste management, highlighting the interplay between organs and biochemical processes that safeguard the body’s health and equilibrium.
Excretion Definition:
- Excretion is the process of removing toxic materials and waste products of metabolism from organisms.
Carbon Dioxide Excretion:
- Carbon dioxide, a waste product of respiration, is excreted through the lungs during the process of breathing.
Urea Production:
- Urea is a toxic waste product produced in the liver from the breakdown of excess amino acids. It is later excreted by the kidneys in urine, playing a crucial role in maintaining nitrogen balance in the body.
Biology – How the Kidneys Work – (Kidneys Part 1/3) #27
- Components of the Urinary System:
- Kidneys: Remove urea and excess salts and water from the blood to form urine.
- Ureters: Transport urine from the kidneys to the bladder.
- Bladder: Stores urine until it’s ready to be expelled.
- Urethra: Conducts urine from the bladder to the outside of the body.
- Need for Excretion:
- Excretion is necessary to eliminate toxic substances, including urea, preventing their buildup in the body.
Nephron Structure:
The nephron consists of:
Bowman’s Capsule: Surrounds the glomerulus.
Glomerulus: Capillary network for blood filtration.
Tubules: Include proximal and distal convoluted tubules, loop of Henle, and collecting duct.
Nephron Function:
(a) Glomerulus Filtration: Filters water, glucose, urea, and ions from the blood.
(b) Reabsorption: Returns glucose, some ions, and most water back into the blood.
(c) Urine Formation: Results in the production of urine containing urea, excess water, and ions.
Liver’s Role in Amino Acid Assimilation:
The liver assimilates amino acids by converting them into proteins.
Deamination in the Liver:
Deamination is the removal of the nitrogen-containing part of amino acids in the liver.
This process leads to the formation of urea, which is then excreted by the kidneys as a waste product in urine.
Biology – Structure of the Kidneys – (Kidneys Part 2/3) #28
Excretion in Humans – IGCSE Biology 2020-21
11.1.1 Features of Gas Exchange Surfaces | CIE IGCSE Biology Revision Notes 2023 | Save My Exams
