- excretion is the removal of toxic waste substance from the organism
- the waste products removed by excretion are those which are the result of metabolic reactions
What are the primary sites for excretion on a plant known as?
The stomata (singular: stoma)
Briefly describe homeostasis...
The process of keeping the conditions inside the human body relatively constant, despite the many changes that constantly occur inside and outside the body
The kidneys are one of the major organs which play a key role in homeostasis and excretion. Elaborate...
- the kidneys filter the blood
- remove any unwanted substances
- control the concentration of of water and solutes in the blood as well as in other body fluids
Along with the kidneys, what organs play main roles in the excretory systems and how?
- the lungs remove carbon dioxide
- the skin removes urea as part of sweat
Briefly breakdown the functions of of the kidneys in the urinary system...
- each kidney is supplied with oxygenated blood and nutrients via a renal artery
- the renal artery branches from the aorta, so blood enters the kidneys at high pressure
- the blood is filtered in each kidney before passing out via a renal vein to the inferior vena cava
- blood vessels take the blood through the kidneys where the waste products are removed into convoluted tubules
- these tubules join together to form the ureter
- urine then passes out of the ureter and into the bladder where it is stored
Describe how the bladder works in the urinary system...
- from the bladder is a tube which runs outside of the body called the urethra
- the walls of the urethra container two ring like muscles called sphincters
- these contract to close the urethra and hold back the urine
- the lower sphincter muscle is controlled consciously
- the upper sphincter muscle is involuntary and automatically relaxes when the bladder is full
What are the ureters?
Tubes leading from the kidneys to the bladder for urine to pass down
What is the urinary system designed to do?
The urinary system is designed to remove waste products like urea, as well as excess ions and water from our blood