A2 BIOLOGY
UNIT F214
MODULE 2:
EXCRETION
Dr. Sona Arya
E – mail: sona.arya@stokesfc.ac.uk
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?
B
C
A
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.
Feature
Hepatocyte
Sinusoid
Bile canaliculus
Kupffer cells
Intralobular vessel
/ Branch of
hepatic vein
What they are and their function
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
 http://www.nottingham.ac.uk/nursing/sonet/rlos
/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 CO2 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
 http://www.youtube.com/watch?v=mEF
PdNv2Ddk
 (Drugs make you ugly)
If alcohol was discovered today, it would
be classified as a class A drug.
http://www.youtube.com/watch?v=1a687t
Dtwyk
TOXINS CAN BE RENDERED
HARMLESS IN THE LIVER BY…
INCLUDE HYDROGEN PEROXIDE)
(PAGE 11 –
 Oxidation
 Reduction
 Methylation - replacing an H with a CH3.
 Combination with a harmless molecule.
DETOXIFICATION OF ALCOHOL
Alcohol (ethanol)
TASK ---- 10 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/email 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 50-51 textbook)
 Complete pages 31-35 of booklet
 Then swap after break (do F216)