Excretory Flashcards
What is excretion
It is the removal of metabolic and nitrogeous waste from the body to maintain homeostasis in the body.
What is excretory system?
The organs that are involved in the formation, storage and elimination of urine constitute the Excretory system.
Give reason
Excretion is an important metabolic process
It is important as it removes urea (nitrogenous waste) which if allowed to accumulate in the blood, can be fatal.
State 5 harmful wastes which are removed from the body
- Carbon dioxide and water vapour
- Nitrogenous metabolic waste
- Excess salts and vitamins
- Excess water
- Bile pigments
How is carbon dioxide and water formed in our body? How is it removed
The cells in our body liberate energy by oxidising glucose which produces CO2 and water.
CO2 is expelled by lungs while excess water is expelled by sweat
State the nitrogenous wastes which are expelled from the body
Urea, Creatinine, Uric acid, Ammonia.
How is Urea formed?
After digestion, extra amino acids in the body cannot be stored. Hence the liver breaks the amino acid into usable glucose and urea which needs to be excreted out
What type of salts and vitamins are excreted
Excess common salt (NaCl) and water-soluble vitamins like B&C are eliminated
How does water help in excretion process
Water is useful in dissolving the harmful substances to carry them out
which bile pigment is removed from the body and how?
yellow bilirubin is excreted with faeces and in urine
these pigments are modified in the intestine to give faeces their brown-ish yellow colour
Write the 4 organs which help in excretion of substances from body
- Kidneys: they are the primary excretory organs which remove nitrogenous wastes like urea from the blood
- Skin: Sweat excretes water, NaCl and small amounts of urea
- Lungs: They excrete CO2 from our body through the expired air
- Liver: detoxifies ammonia by converting it to urea
Define Homeostasis and Osmoregulation
- Homeostasis refers to the processes which maintain a healthy internal state
- Osmoregulation is the process of maintaining salt-water balance in the body by the kidney
What is the location of kidneys?
Kidneys are 2 bean-shaped organs located on either side of the backbone and are protected by the last 2 ribs
Give reason
The right kidney is at a slightly lower level than the left
To accomodate the liver
State location and function of Ureter
- Ureter arises from the Hilum of each kidney and joins the urinary bladder
- Carries urine from the kidney to the urinary bladder
Expanded part of ureter into the kidney is called renal pelvis
State location of Hilum
Hilum is present in the median surface of each kidney
State location and function of Urinary bladder
- It is located in the lower abdomen
- It stores urine temporarily
State location and function of urethra
- It arises from the urinary bladder to the outside of the body
- carries urine from urinary bladder to the outside of the body
State the function and location of Sphincter
- Gaurds the opening of urinary bladder into the urethra
- it relaxes to allow micturition
What is micturition
Micturition is the process of removal of urine from the urinary bladder to the outside of the body through the urethra under the impulse of the nervous system
What are uriniferous tubules
structural functional unit of kidneys
What is malpighian capsule?
the glomerulus and bowman’s capsule is together known as malpighian/renal capsule
why does cortex have dotted appearance?
because of the bowman’s capsule and pct which makes it dotted
what and where is Glomerulus
it is a knot like mass of blood capillaries fitted closely inside bowman’s capsule
Where is loop of henle
It is part of the nephron before the pct in the medulla of kidney
Where is pct and dct
both lie in the cortex
pct connects bowman’s capsule to loop of henle
dct connects loop of henle to collecting duct
Why does medulla have stripped appearance
it has stripped appearance due to loop of henle ad collecting duct
What is vasa recta
it is the secondary capillary network which arises from the efferent arteriole
What is ultrafiltration
It is the process of filtration of water, salt, urea, amino acids, glucose from the blood in the glomerulus to the bowman’s capsule due to high hydrostatic pressure caused due to difference in diameter of the afferent and efferent arteriole.
