Human Excretion Flashcards
What is excretion ?
The removal of metabolic waste
What does the Kidney do?
- Balances the amount of water in your body - osmoregulation
- Filters urea
- Removes excess water, salts and urea
As the blood is filtered at high pressure…..
The kidney selectively reabsorbs any useful materials (glucose, salt ions and water)
What does the kidney produce ?
Urine
Which contains water, urea and salts
How is urea produced?
Urea is produced in the liver when excess amino acids are broken down
What are the excretory organs?
Lungs, kidneys and skin
Excess CO2 is removed through the…..
Lungs
Excess urea, water and salts are removed by….
The kidneys and leave the body as urine
Excess water and salts leave the body through….
Skin through sweat
How do the kidneys regulate the osmotic pressure
Extensive filtration and purification - osmoregulation
Kidneys remove the the blood….
The nitrogenous wastes and then excrete them in the form of urine
How is the filtrate blood carried away from the kidneys
By the renal vein
What does the urinary system consist of?
Kidneys, ureters, bladder and urethra
How does the urinary system work?
1) kidneys filter blood to remove unwanted substances
2) ureters move urine from kidneys to bladder
3) bladder is a reservoir for urine
4) urine excreted through urethra
What a nephron responsible for?
Cleaning the blood
In a nephron at the start is blood at high or low pressure?
High
How does the structure of the blood vessels entering and leaving the glomerulus help to move glucose into the Bowman’s capsule?
The after went arteriolar is significantly wider than the efferent arteriole
Pressure increase in the Bowman’s capsule
What type of blood vessels are found in the glomerulus
Capillaries
What does high pressure help
The ultrafiltration of the blood
What does small molecules do in a nephron?
They are filtered out and pass into the nephron
What do large molecules do in the nephron
They are too big to fit through the capillary wall, remain in blood
What molecules are selectively reabsorbed into the bloodstream?
All glucose originally filtered out
Water required to maintain a constant water level
Ions
What happens to the molecules which are not selectively reabsorbed ?
They continue along the nephron tubule as urine
What happens in the loop of Henle?
More water, sodium ions out (by diffusion and AT)
Why does selective reabsorbtion occur?
Because during ultrafiltration, important components of the blood is filtered out and need to be reabsorbed into the body
Where does selective reabsorption occur?
In the proximal convoluted tubule (extends from Bowman’s capsule)
How is the proximal convoluted tubule adapted for selective reabsorption?
Has a microvilli cell lining to increase surface area
One cell thick
Mitochondria
What is ultrafiltration ?
The filtration of particles / molecules based on their size and under pressure
What is the name of the target cells that line the collecting duct?
Epithelial cells
What happens when receptor molecules bind to the ADH
It triggers proteins in the cell membrane to form pores that allow water to move freely out of the collecting duct by osmosis
Increase water reabsorption
Decrease blood concentration
What does ADH do?
Tells your kidneys how much water to conserve
Explain the role of ADH in regulating the water content of the blood
1) hypothalamus detects solute concentration of blood
2) if water concentration is low, pituitary gland secreted ADH
3) ADH travels in plasma of blood
4) Makes collecting ducts more permeable today water ( allows more water to be reabsorbed back into blood during selective reabsorption)
What does FSH help with
Pubertal development
Function of women’s ovaries and mend testes
What does the ride of LH trigger
Ovulation
