Removal of Waste in Animals Flashcards
Why are materials excreted?
accumulation of waste (from metabolism, growth and respiration) is toxic
What are the wastes excreted, organs, and organ system involved in sweat?
wastes excreted: urea, water, salt
organ: skin, hair, nails
system: integumentary
What are the wastes excreted, organs, and organ system involved in urine?
wastes excreted: urea, uric acid, ammonia
organs: kidneys, bladder
organ system: urinary
What are the wastes excreted, organs, and organ system involved in exhaled air?
wastes excreted: carbon dioxide
organ: lungs
organ system: respiratory
What are amino acids and why are they excreted?
nitrogen-containing molecules used by animals in synthesis of proteins and other compounds, e.g. creatine, peptide hormones, and some neurotransmitters.
Animals often consume more amino acids than necessary, so excess is converted to nitrogenous waste
how is nitrogenous waste transported?
in the blood to the kidneys
Where are the nephrons located?
in the cortex and medulla of the kidneys
What do nephrons do?
they are excretory tubules which produce urine in the process of removing waste from the blood.
Describe the structure of a nephron.
They are a long tubule, about 3-5cm. At one end is a cup-like structure called Bowman’s Capsule that encloses a cluster of blood capillaries called the glomerulus.
Explain the process of filtration.
- unfiltered blood containing waste enters the glomerulus through a narrow artery called the afferent arteriole.
- Fluid from the blood diffuses into Bowman’s Capsule from the glomerulus.
- This material, called filtrate, moves to the proximal tubule.
What does filtrate contain
salts including sodium and chloride, as well as water, glucose, amino acids and nitrogenous wastes.
This composition is altered as certain materials are selectively reabsorbed into the blood capillaries surrounding the proximal tubule.
What materials are reabsorbed in the proximal tubule, and why?
amino acids for protein synthesis
glucose for respiration
sodium ions for metabolism
water for metabolism
What tissue lines the proximal tubule as an exchange surface?
epithelial tissue.
Describe the properties of the epithelial tissue in the proximal tubule as an exchange surface.
Thickness of one cell and each cell has microvilli forming a brush border for surface area.
Once materials have been selectively reabsorbed from filtrate, where does the excess go?
Moves out of the nephron via the collecting ducts.
what do collecting ducts do?
drain into the ureters which transport urine to the bladder.
What is osmoregulation?
The maintenance of the amount of solute (including glucose, sodium, potassium and chloride) in the body’s water supply.
What does the pituitary gland do for osmoregulation?
it is in the brain, and responds to changes in blood osmolarity by regulating production and secretion of antidiuretic hormone (ADH).
what does antidiuretic hormone (ADH) do/
it is transported in the blood to nephrons where it binds to receptors on epithelial cells. This causes the tubule and collecting duct to become more permeable to water, increasing the volume of water that is reabsorbed into the body (less is excreted in urine).
If the volume of water in the blood is excessively high, state its osmolarity and describe the response
the osmolarity is below tolerance limit (not enough solutes in blood), so the pituitary gland decreases production of ADH and less water is reabsorbed, with more excreted in urine.
if the volume of water in the blood is excessively low, state its osmolarity and describe the response
the osmolarity is above tolerance limit (too many solutes in blood) so the pituitary gland increases production of ADH and more water is reabsorbed, with less excreted in urine.