excretion: biology o level
DESCRIPTION
hi guys! This is my latest slide on Excretory system, based on Cambridge GCE 'O' level syllabus. These slides cover much on the essential points and might not be really comprehensive. These slides are constructed to be interactive to further boost your understanding by eliminating superfluous words and adding more animations. Thus, I RECOMMEND you to download the slides to access the many animations to interact with your mind. Follow my slideshare profile to receive updates on new slides!! or contact me: Email: [email protected] facebook: faiz abdullah twitter: @fazzydoo if you have questions or would like to address mistakes on my slides or simply just to request me to personally make your slides. All images and materials are copyright protected and have no affiliations to meTRANSCRIPT
EXCRETION
PREPARED BY: FAIZ ABDULLAH
EXCRETIONThe removal of toxic waste products of metabolism from the body
What for?
If these waste products are allowed to build up, they would quickly become toxic
REMOVE WHAT EXACTLY?
Waste products of metabolism
Carbon dioxidewater Bile pigments
Ammonia Uric AcidUrea
ORGANS OF EXCRETION
Lung
Kidney
Organs Products excreted Method of removal
CO2
Urea, Nitrogenous waste, variety of ions dissolved in water
Exhalation/Expiration
Urine
CAUTION: EGESTION OF FAECES FROM ANUS NOT
EXCRETION
This is because faeces is not a product of metabolism
NOW, LET’S LOOK AT YOUR URINARY SYSTEM
SEVERAL STRUCTURES YOU NEED TO KNOW..
Removes excess water and wastes, such as urea, from the blood to form urine
Note: In a diabetic patients, kidneys remove some glucose present in blood thorough urine
Two muscular tubes
Urine moves down here
How?
Spontaneous rhythmic peristaltic constrictions of the uterus wall
Helped by gravity
To where?
Urinary bladder
Bladder is a muscular bag in which urine accumulates gradually
Stores urine
Urine goes down to Urethra next by contraction of muscles
Carries urine out of the body
In males urethra passes through penis
Spincter muscle
Controls the flow of urine
Urination can be delayed as per convenience
IF YOU CUT YOUR KIDNEY IN HALF….
NEPHRON
About a million microscopic tubes called nephrons are located in each of the kidneys
Nephrons consist of a capsule shaped like a cup Bowman’s capsule, and a long narrow tube
STRUCTURE OF A NEPHRON (SING.)
LET US LOOK AT SOME PROCESSES THAT HAPPEN IN THE NEPHRON, PARTICULARLY….
Ultrafiltration Selective REabsorption
Ultrafiltration
Ultrafiltration of BLOOD from glomerulus takes place in the BOWMAN’S CAPSULE
A high pressure is built up
Squeezes water, urea, ions and glucose out of blood and into Bowman’s capsule
Large molecules move back into the blood through the capillaries that surround the tubule
As the liquid flows along the tubules in the nephron
Useful substances (like water, glucose, amino acids) are selectively reabsorbed
SELECTIVE REABSORPTION
These substances move back into the blood through capillaries that surround tubule
Excess water, mineral salts, urea and uric acid pass into the pelvic region of the kidney to form urine
NEXT: ROLE OF ADH IM REGULATION OF OSMOTIC CONCENTRATION
ADH ANTIDIURETIC HORMONE
Pituitary Gland releases ADH into blood
ADH
HOWEVER, IT DOES NOT RELEASE ANYHOW.
NEEDS INSTRUCTION FROM BOSS HYPOTHALAMUS
=
Detects problem
High water concentration in blood plasma
OR
Low water concentration in blood plasma
Hey pituitary gland, something is wrong.
FIX IT!
UGH….SHOULD ASK FOR A RAISE NEXT TIME!BIAR KO SASAK AKU GANYA KAU SURUH
High H2O
Pituitary gland secrete less ADH
Kidney tubules to reabsorb less water
More urine produced (diluted)
Less H2O
Pituitary gland secrete more ADH
Kidney tubules to reabsorb more water
Less urine produced (concentrated)
Water conc goes back normal
KIDNEY FAILURE
Kidney failure may result from infection or sudden shock.
Kidney failure patients must be treated with artificial kidney machines or undergo kidney transplants
DIALYSIS
The diffusion of some molecules across a partially permeable membrane is called dialysis
Impurities, such as urea molecules, high concentration in blood, move into dialysis fluid
HAEMODIALYSISThe dialysis of blood