Excretory system Flashcards
What kinds of waste do our bodies produce?
Sweat, carbon dioxide gas, feces, and urine
How does sweat leave our bodies?
It is released through pores in the skin
How does water vapour leave our bodies?
It is exhaled from the lungs
How does carbon dioxide leave our bodies?
It is exhaled from the lungs
How do undigested food materials leave our bodies?
They are formed into feces in the colon and excreted from the body as solid waste in bowel movements
What is the main function of our excretory system?
To filter blood to remove waste and excess substances such as urea and water. It also eliminates this waste, a process called excretion
What is the main function of the kidneys?
To filter blood through millions of nephrons
What are nephrons?
Small filtration units
Where do the kidneys receive blood from?
From the renal artery, which is connected through capillaries surrounding the nephrons
How do the nephrons filter blood?
As blood circulates in the capillaries, the nephrons filter it by removing excess substances through the process of diffusion
Does the composition of urine vary?
Yes, from one person to the next and from one time of the day to another
What is urine made of?
Mostly water, but it also contains waste products such as: urea, uric acid, potassium, sodium, vitamins, and urochrome
What is urochrome?
A pigment that gives urine a yellow colour
Where does urochrome come from?
The destruction of hemoglobin present in old red blood cells
What in the urine would indicate a health problem like diabetes?
Glucose and proteins
What are ureters?
Tubes connecting the kidneys to the bladder and they carry urine to the bladder
What is the bladder?
A stretchy bag made of muscles
What does the kidney store?
Urine before it is expelled
Where is the sphincter?
It is located at the bottom of the baldder
What is a sphincter?
A circular muscle
What does the sphincter do?
It contracts to stop the flow of urine and relaxes to expel it
What is the urethra?
A tube which transports urine from the bladder to outside the body
What is homeostasis?
The body’s ability to maintain balance (mineral salts in blood, blood pH, water, temperature)
When does the volume of blood increase?
When there is too much water in the blood
What happens when the volume of blood increases?
The pituitary gland send a message to the kidneys which will remove water from the blood resulting in more diluted urine (less solute per volume of urine). Therefore the concentration of mineral salts in the blood will return to normal level
What happens if we eat too much salty food?
The large intestine will absorb a lot of minerals and the concentration of minerals in the blood will be too high. The pituitary gland sends a signal to the kidneys to hold on to water. Therefore the kidneys remove less water and more mineral salts from the blood, resulting in a more concentrated urine (more solute per volume of urine)
