1. I did this one the last one was rubbish
Excretion Mk 2
I did this one the last one was rubbish

2. What is it?
Excretion is the removal of waste and excess stuff from your body and is a powerful area of HOMEOSTASIS
The reactions in your body – your METABOLISM produces waste and these need to be removed.
Examples include CO2, nitrogenous wastes (from deamination), H2O2
The majority of waste is toxic and could cause damage so need to be processed or removed
What excretory organs can you name?

3. Nitrogenous waste (urea)
Terms never to confuse!!
Excretion versus egestion
Metabolic waste – substances produced from chemical reaction that may be toxic at high levels in the body
Carbon dioxide
Nitrogenous waste (urea)

4. Waste metabolites Urea Carbon dioxide
Made from deamination of xs amino acids in liver:
Removal of amino group  ammonia + keto acid.
React with CO2 to make less soluble, less toxic urea. Energy dependent reaction.
Transported in blood plasma
Filtered in kidney to make urine
Carbon dioxide
Respiratory product from all cell
Transported in blood
1) dissolved in blood plasma
2) directly with Hb
3) Forming hydrocarbonate ions (carbonic anhydrase)
Removed by lungs
Respiratory Acidosis
pH less than 7.35
Characteristic symptoms
XS proteins and amino acids can not be stored, they are transported to liverDeamination- removal of amino group from amino acids producing ketoacids and ammonia (highly soluble, toxic) subsequently converted (addition of CO2 to make urea and water) to less soluble, less toxic compound UREA (CO(NH2)2
Respiratory acidosis- slowed/difficulty breathing, headache, drowsy, restlessness, tremor and confusion

5. There are four excretory organs
1. Your lungs – remove CO2
2. Your skin – some of your sweat is excess water and also contains nitrogenous wastes (UREA)
3. Your Kidneys – regulate water and remove excess salts, impurities and glucose
4. Your Liver – what this lesson is about – this breaks down loads of metabolic waste products and other toxins your body takes in – there is no need for DETOX!!!!

6. Structure of the liver

7. Liver Structure Big organ – biggest internal one anyway
Two main blood vessels
Hepatic Artery – Oxygenated blood for a lot of respiration
Hepatic Vein – To remove all the CO2 from the Respiration
Other important ones
Hepatic Portal Vein – Carries products of digestion from the DUODENUM to the liver – this allows the products of digestion to be purified before they carry on
Bile duct – carries bile to the gall bladder – what does this do?

8. Liver structure

9. Lobules and Sinusoid – ensure you know all the bits

10. Histology - microscope

11. Questions – lets see what you remember
What is excretion and what is it’s function?
What are your main excretory organs and what do they excrete?
What are the main structures that carry blood and other stuff to and from the live called and where are their sources/ destinations?
What is the functional part of the liver called, and what are the units within it called?
What are the phagocytic cells called and what do they break down?
What are the principle jobs of the liver?

12. Livers primary jobs
Storage of Glycogen – Glycogenesis (controlled by insulin)
Break down of Red Blood Cells into bilirubin (why poo is brown)
But the one you got to know in detail is the Deamination and the Ornithine Cycle
Sounds flashy as right!

13. The process Removal of Amino Groups – DAMINATION
This leaves us with Amino Groups and Organic Acids - these can be converted into?
Carbohydrates (GLUCONEOGENESIS) or Glycogen (GLYCOGENOLYSIS)
Amino Acids Ammonia (NH3) + Organic Acid
Ammonia is too toxic to excrete safely (fish can do it as it dilutes quickly)
So Ornithine Cycle be needed
Deamination

14. Basically Ammonia + Carbon Dioxide Urea + Water
Of course it is way more complicated than this!
Urea is transported into the blood at the sinusoid and carried to the
Kidney

15. Picture – though not the full picture
Carbon Dioxide and Ammonia make – Carbamoyl Phosphate
This leads to Citruline when it is combined with Arginine
The enzyme Argininsuccinate Synthase makes – can you guess? It uses Aspartate to make water and AMP from ATP
Argininsuccinate this is converted into
Arginine which when converted into Ornithine makes
Urea
Simple Yes

17. Detoxification
Quick question – are detox diets a massive waste of time?
Yes – the only DETOX you ever need is after heavy drug addiction or poisoning
Normal eating does not occur – your liver sees to this
It removes Alcohol (into Ethanal then acetic acid) – too much leads to Cirrhosis (scarring of the liver)
Paracetamol – metabolised in the liver too much leads to liver and kidney issues
Insulin – excess is broken down in the liver and cells in the liver also respond to it

18. Excretion to the MAX mk 3
Kidneys – what do you already know – white boards – five minutes no talking gossiping or unnecessary whinging
Job – filtering blood and removal of blood bourne toxins
Principle toxin - UREA
Also deals with Excess Water, Excess Salts, Excess Glucose
Can you draw the functional unit of the kidney the NEPHRON?

19. Gross Anatomy

20. Nephron
How does it all work?

21. The Jobs
Ultrafiltration – all the stuff is SQUEEZED out of the Glomerulus
There are small gaps on the Capillary endothelium and Bowman’s capsule epithelium
Reabsorption is selective – your body wants glucose, salts, amino acids and vitamins back in and moves them by active transport and facilitated diffusion
Water moves by OSMOSIS
The PCT has microvilli to increase
Surface Area
What remains in the filtrate is collected into the Collecting duct and drains into the Calyx then ultimately to the Pelvis and the Urethra