B6: Excretion and Osmoregulation Flashcards
what is excretion?
the process by which waste and harmful substances produced by the chemical reactions in the body are removed from the body
difference between excretion and egestion
egestion is removal of undigested food as faeces while excretion is removal of waste products of metabolism from the body
what are the waste products of plants?
- Oxygen - from phtosynthesis
- carbon dioxide - from respiration
- water - from respiration
- organic waste products eg tannins, alkaloids, anthocyanins, salts of organic acids such as calcium oxalate
Mechanism of excretion in plants
- diffusion from the leaves- oxygen, carbon dioxide and water vapour
- some waste compounds are converted to other other substances such as oils, tannins and calcium oxalate
- organic waste is shed with the leaves.
Products excreted by animals
- Bile pigments - eg bilirrubin produced by the breakdown of haemoglobin from red blod cells.
- Nitrogenous compounds produced by breakdown of proteins and aminoacids, mainly urea and ammonia.
- carbon dioxide
- water
what are the excretory organs in plants?
- leaves
- Barks
exctretory organs in humans
- kidney: water, urea, salts
- lungs: carbon dioxide
- liver: bile pigments such as bilirubin
- skin: water, urea, and salts
Label parts of the excretory sytem
structure and function of the kidney. label the diagram with names and functions
structure of the nephron
Label the nephron and state what happens at each numbered region
- renal artery has greater diameter than renal vein creating high pressure in the capillaries of the glomerulus
- the pressure forces liquid(filtrate) into the Bowmans Capsule
- the filtrate contains useful substances and waste. large molecules and corpuscles cannot pass.
- Convoluted tubules reabsorb the useful substances eg. glucose, salts and water
- loop of Henle absorbs water and salts
- blood caillaries reabsorsb useful substances and secrete toxic substances into the tubule
- Blood has reabsorbed 80% of the filtrate
- Urine passes to the pelvis
Where does pressure filtration (utrafiltration occur)
the glomeruli
what are the substances present in the filtrate
- useful substances: glucose, water, salts, hormones, vitamins, aminoacids
- waste substances: water, urea, bile salts, salts
What is selective reabsorbtion?
The absorption of some of the useful components of the glomerular filtrate back into the blood as the filtrate flows through the nephrons of the kidney.
where does selective reabsobtion take place?
- proximal convoluted tubules: glucose, hormones, water, vitamins, amino acids, some salts
- loop of Henle: water
- distal convoluted tubule: some salts and water
How is urine produced in the nepron?
- Ultrafiltration (pressure filtration)
- Selective reabsorbtion
How is water reabsorbed into the blood from the nephron?
osmosis
How are substances such as amino acids glucose, hormones etc reabsorbed into the blood
diffusion and active transport
What is the composition of urine?
- urea
- excess salts
- excess water
What is homeostasis?
the maintenance of near normal internal conditions in the body by mechanisms of negative feedback
feedback?
Negative feedback involves contolling a system, monitoring the effects of change and continually making adjustments.
Skin structure : Identify the parts and regions of the skin
What is negative feedback?
a type of regulation in biological systems in which the end product of a process in turn reduces the stimulus of that same process.
4 main funtions of Homeostasis
- thermoregulation
- osmoregulation
- Glucose control
- Control of Carbon dioxide levels
Describe osmoregulation
control of concentrations of salts and water in the blood with normal limits
describe the regulation of carbon dioxide concentration in the blood
describe the regulation of glucose concentration in the blood
Describe Thermoregulation in humans
label the skin
what is know as the body’s thermostat?
The Hypothalamus
How aspects of homeostasis does the hypothalamus regulate
- body’s temperature
- water and salt content of the blood(osmoregulation) by stimulating the pituitary gland to secrete ADH
which structure detects changes in the temperature of the blood?
the Hypothalamus
which structure is responsible for regulating water and salt content of the blood?
The hypothalamus
which structure regulates carbon dioxide concentration in the blood?
medulla oblongata in the hind brain.
what structure detects changes in the concentration of glucose in the blood?
Cells in the pancreas
true or false: insuin and glucagon are hormones
true
