Excretion Flashcards
(33 cards)
What is excretion?
The removal of waste products of metabolism from the cell.
What is homeostasis?
The maintenance of a constant internal body environment.
How do we excrete waste?
Lungs excrete water & CO2, kidneys excrete water & urea, skin excretes water & salt.
What do ureters do?
Carry urine from kidneys to the bladder.
What is the bladder?
A muscular organ that stores urine.
What is the function of the kidney?
Filters blood to remove unwanted material.
What is the urethra?
A tube that carries urine from the bladder out of the body during urination.
Where are the kidneys located in the human body?
In the lower abdomen.
What is the cortex of the kidney?
The outer layer that filters blood.
What is the medulla of the kidney?
The part responsible for reabsorption.
What are the roles of the kidneys?
Filter blood, absorb needed substances, and pass waste products to the bladder for storage/secretion.
How does blood enter the kidneys?
Blood arrives from the aorta & vena cava, becoming the renal artery & renal vein.
What occurs in the outer cortex of the kidneys?
Blood is filtered to remove small pigments, glucose, amino acids, water, and urea.
What happens during reabsorption in the kidneys?
Desired substances like glucose & amino acids are reabsorbed into the bloodstream in the medulla.
What is secretion in the kidneys?
Undesired substances filtered from blood are transported to the bladder and excreted as urine.
What is urination?
The passing of urine from the body.
What is urine composed of?
Water & urea.
What is the path of urine leaving the body?
Urine passes from the bladder through the urethra and is excreted from the body.
What is osmoregulation?
The kidneys are the osmoregulatory organs, regulating water intake and loss.
What is a nephron?
The functional unit of the kidney.
Where does filtration occur in the nephron?
In the Bowman’s capsule.
What happens in the Bowman’s capsule?
Small molecules are forced out of the plasma into the lumen, forming glomerular filtrate.
Why does blood enter the glomerulus under pressure?
Efferent arterioles are narrower than afferent arterioles, forcing plasma filtering.
Why are there many capillaries surrounding the PCT, loop of Henle, and DCT?
For reabsorption and secretion.
