A2 BIOLOGY UNIT F214 MODULE 2: EXCRETION Dr. Sona Arya E – mail:

IN TODAY’S LESSON....  Recap on Liver Histology – how much can you remember?  Finish off Liver Functions (Detoxification of substances by the Liver)  Feedback and Reflection on Ecology Test  Exam Re-sits  Kidney Dissection (Gross structure) R18  Examine sections of Kidney tissue (Histology) and Practice Drawing structures (needed for F216

A2 BIOLOGY UNIT F214: THE LIVER

LAST LESSON...  You learnt about …Blood Supply to the liver …Cells of the liver  How much can you remember?  On your white boards......

 Which of these vessels supply oxygenated blood to the liver from the heart? A hepatic artery B hepatic vein A  Name the blood vessel that brings blood to the liver from the small intestine? Hepatic portal vein  What are liver cells called? (correct spelling please!) Hepatocytes

Name the channels that allow blood to flow pass very close to all the liver cells Sinusoids What do Kupffer cells do? (2) Remove bacteria and break down old red blood cells The bile duct is connected to the central vein by tubes called......? (correct spelling please!) Canaliculi

CAN YOU ADD LABELS? A B C

HOME WORK CHECK …. Up to 100,000 lobules each 1-2 mm in diameter. Complete the right hand column of the table, found on page 7. FeatureWhat they are and their function Hepatocyte Sinusoid Bile canaliculus Kupffer cells Intralobular vessel / Branch of hepatic vein

HOME WORK - EXAM PRACTICE Practice questions on the exam objectives:  Describe with the aid of diagrams and photographs, the histology and gross structure of the liver for your exam? Extension : Exam Qs /Activities in Excretion Booklet

LIVER FUNCTIONS

FUNCTIONS OF THE LIVER  /bioproc/liverphysiology/7.html /bioproc/liverphysiology/7.html  Protein Metabolism includes i) deamination and ii) urea production via the ornithine cycle (in cytosol and mitochondria)  See page 8 Excretion booklet and page 40 in the textbook

EXAM OBJECTIVES  Describe the formation of urea in the liver, including an outline of the ornithine cycle

TASKS PG 40 OF BOOKLET  Explain why deamination of excess amino acids is needed and what the process is … Include all equations  Ornithine Cycle to produce safer urea. Draw and learn the cycle, and explain why it is necessary … Include all equations  20 min

DEAMINATION – KEY POINTS  Amino acids contain nitrogen in their amino group  Excess amino acids have their amino group removed forming ammonia and organic acid (keto acid) - this process is called deamination  The keto acid can be respired to give ATP or converted to carbohydrates and fats

ORNITHINE CYCLE  Ammonia is too toxic for mammals to excrete directly, so is combined with CO 2 in the ornithine cycle to create safer urea  Urea released into the blood  Kidneys remove urea as urine

EXAM OBJECTIVES  Describe the roles of the liver in detoxification

DETOXIFICATION IN THE LIVER CAN BE OF INTERNALLY OR EXTERNALLY GAINED SUBSTANCES SUCH AS….. What is key definition?

DRUGS  PdNv2Ddk PdNv2Ddk  (Drugs make you ugly) If alcohol was discovered today, it would be classified as a class A drug. Dtwyk

TOXINS CAN BE RENDERED HARMLESS IN THE LIVER BY… (PAGE 11 – INCLUDE HYDROGEN PEROXIDE)  Oxidation  Reduction  Methylation - replacing an H with a CH 3.  Combination with a harmless molecule.

DETOXIFICATION OF ALCOHOL Alcohol (ethanol)

TASK MIN USING PAGE 41 TEXTBOOK  Draw the flow diagram to show Detoxification of Alcohol and add the name of the enzymes to the diagram (learn the names)  Describe the role of NAD and fatty acids in the development of a “fatty liver” (homework check)

STRETCH AND CHALLENGE  Research and Summarise information as a leaflet on liver disorders to show your understanding of liver functions Choose one disorder from:  Gallstone  Jaundice (new born)  Hepatitis  Cirrhosis …Liver Histology and Symptoms …Hand in next week/ me

PLENARY – EXAM PRACTICE  Practice Exam Qs on Liver Functions  Less than 15 min  Extension: Using your text books, page 41, answer the questions on page 12 of your booklet and /or exam Qs on pg 17 as extension/homework

ANSWERS  Word Document

ACADEMIC TUTORIAL  AS Exam Re-sits  MPG Sheets  Ecology Test (Reflections)

JAN EXAM RE-SITS  A2 students re-sitting F211 and F212 can collect re-sit forms from 21st September.  Anyone re-sitting F213 should enter their re-sit in March although we will be starting these soon  COL D (Mon) and COL G  The deadline for submitting re-sit forms is Thursday 18th October at 4.00 pm.

ECOLOGY TEST RESULTS  Compare to your MPG  You will need to do a SELF –Analysis on how you did  See back of test for objectives and what you think you need to do to improve  Well Done to those who achieved their MPGs!  I will collect your tests back in today and return next lesson  Everyone below MPG/Grade U needs to do re-do test

AFTER BREAK  Kidney Dissection and Training for F216  On Friday  Group will be split in two  One half use Ground floor LRC and do Independent study task on:  Kidney Failure (pages textbook)  Complete pages of booklet  Then swap after break (do F216)