CBL 1 (W1-2) Liver Flashcards
What are the typical signs and symptoms of a patient with Cholera?
-Severe Diarrhoea
-Dehydration
-Vomiting
-Abdominal pain
What are the typical signs and symptoms of a patient with Tetanus?
-Muscle Spasm
-Fever
-Lockjaw
-Dysphagia
Way to remember:
TetANUS
My Farts Linger Daily
What are the typical signs and symptoms of a patient with Typhoid?
-Fever
-Headache
-Abdominal pain
-Constipation
-Rash
What are the typical signs and symptoms of a patient with Hepatitis?
-Abdominal pain
-loss of appetite
-fatigue
-dark urine
-pale stool
-jaundice
What are the typical signs and symptoms of a patient with TB ?
-Chest pain
-Weight loss
-Loss of appetite
-Night sweats
-Haemoptysis
What is the incubation period/onset of Hepatitis?
1.5-6months
What is the incubation period for Salmonella?
6hrs-6months
What causes the classical symptoms of an acute infection? i.e Fever, Malaise, Aches, Pains and Nausea?
The body produces cytokines such as Interferon which causes the global effects.
What are the prehepatic causes of jaundice?
=Excessive RBC breakdown
-Thalassaemia, Haemolytic anaemia, spherocytosis, sickle cell anaemia
What are the intrahepatic causes of jaundice?
=Dysfunction of hepatic cells / less hepatocytes and therefore reduced ability to conjugate bilirubin
-Viral Hepatitis
-Alcoholic Cirrhosis
-Drug induced jaundice
-Alcoholic hepatitis
-Autoimmune liver disorders
What are the Extrahepatic causes of jaundice?
=Obstruction of biliary drainage which causes hyperbilirubinemia
-Gallstones
-Cancer
-Pancreatitis
What is Kernicterus?
When a baby with Jaundice gets seizures and muscle spasms due to brain damage from the bilirubin crossing the BBB.
What is unconjugated bilirubin?
Bilirubin is bound to albumin in the blood, is therefore insoluble in water and cannot be excreted.
What is conjugated bilirubin?
Not bound to Albumin, therefore water soluble and can be excreted from body.
Explain bilirubin formation.
From the breakdown of RBCs.
-Macrophages (Reticuloendothelial cells) break haemoglobin down into globin and haem (which is reduced to iron and Biliverdin via enzyme Haem Oxygenase). Iron is recycled and Biliverdin is reduced to unconjugated bilirubin
What is Gilbert’s syndrome?
It is a hereditary condition which causes Hyperbilruinaemia due to a Glucuronyl Transferase Definciency and therefore Bilirubin conjugation is slower and therefore less is excreted.
How are patients with Gilbert’s Syndrome affected?
Asymptomatic with normal bilirubin levels however they can become easily and quickly jaundiced when physically stressed.
What gene is affected in Gilbert’s syndrome?
UGT1A1
How is neonatal jaundice treated?
Phototherapy
How does carcinoma of the pancreas cause jaundice?
Enlargement of the pancreas causes the common bile duct to compress leading to jaundice.
How is carcinoma of the head of the pancreas treated?
Pancreatoduodenectomy by Whipple resection (removal of the head)
How does gallstones (aka Cholethiasis) cause jaundice?
Causes obstruction of the biliary system resulting in biliary colic and jaundice.
How does Malaria cause jaundice?
P.falciparum parasite causes intravascular haemolysis which causes and increase in Bilirubin and therefore Jaundice.
How are gallstones obstructing bile ducts treated?
Inserting a stent using ERCP or Laparoscopic Cholecystectomy
How is Malaria treated?
Schizonticides
=type of chemotherapy that kills the parasite in the blood
What is the meaning of febrile?
Fever
What is the meaning of Icteric?
Jaundice
What are the 3 main causes of Chronic Liver Disease?
-Hepatitis
-Haemochromatosis
-Non Alcoholic Fatty Liver Disease
What are the causes Abdominal Distension?
6Fs- Fat, Fluid, Flatus (gas), Faeces, Fetus, Fuminant mass (a smelly mass)
What are Caput Medusae?
Engorged paraumbilical veins
What is associated with Caput Medusae?
Portal Hypertension caused by Liver Cirrhosis
What are the causes of Striae (stretch marks)?
Ascites, intrabdominal malignancy, cushing’s syndrome, obesity and pregnancy
What is Cullen’s sign?
Bruising of tissue surrounding the umbilicus
What is Cullen’s sign associated with?
Haemorrhagic Pancreatitis (late sign)
What is Grey-Turner’s sign?
Bruising in the flanks
What is Grey-Turner’s sign associated with?
Haemorrhagic Pancreatitis
What does a high ALP and normal GGT mean?
ALP and GGT raised indicate and obstruction problem with the liver.
So if GGT isn’t raised, raised ALP will indicate an issue with Bones (e.g Paget’s Disease)
What does a high ALP AND GGT indicate?
ALP and GGT raised indicate and obstruction problem with the liver.
Other than obstruction of the liver, what else can a raised GGT indicate?
Too much alcohol consumption or Obesity
What does a raised AST and a normal ALT indicate?
AST AND ALT raised would indicate damage to the hepatocytes (liver). But if only AST is raised, that would instead point to muscle damage.
What does a raised AST and ALT indicate?
Damaged liver perhaps due to drugs or alcohol. Will want to check for inflammation and fibrosis (i.e Cirrhosis).
What does an elevated T.Bilirubin indicate?
Bile duct / Liver issues, or Haemolytic Anaemia
What is Mastication?
The voluntary activity involving skeletal muscle to aid the chewing reflex.
What are the functions of mastication?
-Prevents airway obstruction
-Lubrication and digestion
-Increase the surface area exposed to secretions
What is the function of amylase?
To breakdown starch
What is the function of mucous in the mouth?
To lubricate food
What are the 3 stages of swallowing?
1.Voluntary (oral) stage = Bolus squeezed into pharynx by tongue
2.Pharyngeal stage = food goes into oesophagus and epiglottis protects it going into the air tract
3.Oesophageal stage = Transport of food from pharynx into stomach via peristaltic contractions
What is the function of the epiglottis during swallowing?
It swings during the pharyngeal stage to protect the airway tract.
Where is the swallowing centre located?
Medulla Oblongata
What is the purpose of the soft palate during the pharyngeal stage of swallowing?
To prevent nasal reflux
During swallowing, the opening of the oesophagus enlarges. How does this happen?
The larynx is squeezed shut and pushed upwards which makes the opening bigger.
Describe the musculature of the oesophagus (i.e the type of muscles present).
-Upper 1/3 = Striated muscle
-Lower 2/3 = Smooth muscle
What innervates the muscles of the oesophagus?
Glossopharyngeal and Vagus nerves
What is primary peristalsis?
When the food bolus is present in the oesophagus
What is secondary peristalsis?
When the oesophagus distends and the bolus moves down towards the oesophageal sphincter and stomach
What is the Vagovagal reflex?
Relaxation of the fundus and body of the stomach to take up to 1.5L of contents
During the emptying of the stomach, what muscle is involved?
Circular longitudinal oblique muscle in the Antrum of the stomach to produce intense peristaltic contraction to constrict the Pyloric Sphincter
Describe the electrical activity of the GI smooth muscle.
Partial depolarisation sweeps along the digestive tract across long distances:
1.Slow waves stimulate the spike potentials
2.Spike potentials happen at -40mV
What causes the GI smooth muscle to stretch?
Parasympathetic innervation via Acetylcholine
What reduces GI smooth muscle contraction?
Sympathetic innervation via Noepinephrine.
What is the pyloric pump and what causes it?
It is the backwards force caused by the spike potential which causes a tightening ring around the pylorus. This regulates the rate of gastric emptying.
How does the contents of the interstitial lumen affect gastric emptying?
Depending on what is present in the intestine (from gastric emptying), chemoreceptors feed this back to Intramural intrinsic plexuses that feed it back to the CNS to organise sympathetic and parasympathetic activity.
If there are amino acids present in the intestine what will the stomach produce?
Gastrin
If there are fats present in the intestine what will the stomach produce?
Cholecystokinin to get the gallbladder and pancreas to contract.
If there is acid present in the intestine what will the stomach produce?
Secretin
What metabolic effects happen as a result of vomiting?
Loss of NaCl, H20, H+
=Metabolic alkalosis
What % does the duodenum, jejunum and ileum make up of the small intestine?
Duodenum- first 5%
Jejunum - 40%
Ileum - 55%
What is Mesentary ?
Mesentary attaches to the abdominal wall with lymphatics (draining) and vessels.
What is the meaning of Migratory Motility Complex of the Small intestine?
The mass clearance of the small intestine. Waves of electrical activity burst to limit the overgrowth of harmful bacteria.
What causes the bursts of electrical activity in the Migratory Motility Complex?
When in the fasted state, the hormone Motilin is released which increases vagal impulses and therefore the movement and emptying of the SI.
What prevents fecal backflow into the small intestine?
The Ileocecal valve
What opens the ileocecal valve to empty the contents of the small intestine?
Gastroileal reflex that is regulated by pressure and chemical irritation
What are the functions of the colon?
-Absorption of water and electrolytes
-Storage of fecal matter
How are short chained fatty acids produced?
After 8-15hrs hours transit time of the chyme, cholonic bacteria arises which synthesises it.
What are mass movements and how often do they occur?
Propulsive movement after eating. Happens 1-3 times per day for about 30 secs over a periods of 30minutes. This sustained contraction leads to defecation.
What is the Gastrocolic reflex?
Increase of mass movements that is mediated by the autonomic nervous system releasing gastrin.
What happens in the defecation reflex?
-There is an increase of afferent signals in the myenteric plexus that causes peristalsis in the colon and sphincter relaxation.
-The parasympathetic activation fortifies the reflex involving the sacral segments of the spinal cord .
How would you treat a patient with Diarrhoea?
-Cessation of eating
-IV rehydration with H2O, NaCl and Sucrose to decrease the gut motility
What do carbohydrates breakdown to?
Carbs–>Glucose–>Pyruvate–>Acetyl CoA –> Goes through the TCA cycle to produce ATP
How is glucose transported across cell membranes?
Facilitated diffusion
NOTE: that it is therefore limited by the availability of transporters.
Where are GLUT1 transporters located?
Most tissues (e.g brain, RBCs and Cornea)
Where are GLUT 2 transporters located?
Liver, kidney, pancreatic B cells
Where are GLUT3 transporters located?
CNS and other tissues
What do GLUT1 transporters do?
Basal glucose uptake
What do GLUT2 transporters do?
Removes excess glucose from blood in the liver and regulates insulin release in the pancreas.
Note: GLUT2 has a lower affinity for glucose
What do GLUT3 transporters do?
Basal glucose uptake
Where are GLUT 4 transporters located?
Skeletal muscle and adipose tissue
What do GLUT4 transporters do?
They increase during exercise due to insulin.
Where is Insulin produced?
Pancreatic B-cells in the Islets of Langerhans
How is insulin degraded?
In the Liver by Insulinase.
How does Insulin affect adipose tissues?
Increases glucose uptake and Lipogenesis and decreases Lipolysis.
How does Insulin affect the Liver?
Increases Glucose synthesis and Lipogenesis and decreases Gluconeogenesis.
IN the Liver, Glucose INcreases with Insulin
(opp of effects around the body)
How does Insulin affect the Striated muscle?
Increases Glucose uptake, glycogen synthesis and protein synthesis.
Under fasting conditions, what provides energy?
Fatty acids
How does insulin affect GLUT4 transporters?
Increases GLUT4 levels and glucose uptake by 15-20 fold.
Why is the brain so highly dependant on Glucose?
It is it’s primary energy source. Insulin has minimal effect on glucose. GLUT1 transporters in the brain have the highest affinity for glucose and therefore readily take it up.
What is Hypoglycaemia?
Low glucose causes nervous system instability leading to fainting, convulsions and a coma if prolonged (since the brain is highly dependant on glucose).
What are the effects of Glucagon in the liver?
Glucagon receptor signalling increases cAMP and PKA to stimulate glycogen phosphorylase to break down glycogen into glucose (glycogenolysis).
How does exercise affect glucagon secreation?
Increases it
How does Adrenaline/Noradrenaline affect glucose metabolism?
=a-adrenergic activation –> Increase Glycogenolysis –>Increases Glucose
=B-adrenergic activation –>Increase Lipolysis
How does Cortisol and Growth hormone affect glucose metabolism?
-Stimulates hepatic gluconeogenesis
-Decreases tissue glucose uptake
-Increases Lipolysis
Note: Stress hormones are protective for hypoglycemia.
Way to remember:
When growing you are preparing the body for long term regulation of your glucose hence the liver stimulation of Glucagon to increase your glucose when needed. Skinning kids, so lipolysis and decrease glucose uptake.
Where is glucose reabsorbed in the kidney?
Proximal tubule
What does the SGLT1 and SGLT2 cotransporter do?
Transports Na+ and Glucose together into the intracellular space (from the proximal tubule) for the GLUT2 transporter to transport it into the cell (of the blood). Na+ is transported further via the Na/K ATPase pump.
How does blood glucose affect the osmorality?
Increases it (causing water loss) and as it is increased in the renal tubules, less is absorbed.
What is Glucotoxicity?
Glucose in high levels causes the alteration (glycation) of proteins (HbA1c) and increases reactive oxygen species causing aberrant cellular messaging, chronic inflammation, endothelial dysfunction and B-cell (pancreas) dysfunction
=TISSUE DAMAGE
Describe the switch to fat metabolism when Insulin is not present?
Insulin inhibits Lipase…so without insulin means Lipase is NOT inhibited.
Lipase is the enzyme that allows triglycerides –> Free Fatty acids —> (via B-oxidation) =KETONES
How is Diabetic Ketoacidosis caused?
-Lack of metabolism
->Ketone production
–>Decreases pH and increases H+
=METABOLIC ACIDOSIS
—>Hyperkalaemia
What tests are used for diagnosing diabetes?
-Urinary glucose
-Fasting blood glucose
-Fasting plasma insulin
-Glucose tolerance test
What Urinary glucose would you expect from a diabetic patient and why.
> 10mmol/L as the renal capacity for reabsorption is exceeded
What are the normal ranges for fasting blood glucose and fasting plasma insulin?
Glucose: 3.4-6.2
Insulin: 10mU/mL
What result would you expect from a Glucose Tolerance test from a Diabetic patient?
Delayed decrease of blood glucose after an oral bolus.
How quickly are Amino acids absorbed compared with Glucose?
SLOW (glucose in comparison is VERY fast)
What is the Deamination of Amino Acids?
The breakdown of AAs that gives rise to Glucose, Fatty Acids and Ketone bodies; or breaks into Ammonia and goes through the urea cycle to give urea.
Unlike glucose and fatty acids, amino acids cannot be stored. What happens instead?
Free Amino acids quickly combine to form peptides and intracellular proteins.
How does Growth hormone and insulin affect protein synthesis?
Increase
How do Glucocorticoids affect protein synthesis?
Decrease- as they mobilise amino acids (breakdown proteins)
What does the protein transferrin do?
Carries the ferrous iron in the circulation
What plasma protein is the most abundant?
Albumin
How does Liver disease affect protein synthesis and how does this physically manifest?
Decreases protein synthesis causing Oedema
What are the temporary use of energy stores in absence of glucose (in order of usage).
1.Fat
2.Protein
What does Cachexia mean?
Loss of body mass that cannot be reversed nutritionally e.g Cancer, Aids, Coeliac disease, COPD, Congestive heart failure, TB
What does a Hypermetabolic state mean?
Elevated levels of cytokines which promote protein breakdown e.g Burns, Trauma, Sepsis
What does a positive nitrogen balance mean and when do you get it?
When there is an increased demand for protein e.g growth, pregnancy, recovery from illness/trauma
What does a negative nitrogen balance mean and when do you get it?
During starvation/malnutrition= the protein intake is insufficient for normal metabolism
What are the major glands of the mouth?
-Submandibular
-Sublingual
-Parotid
Describe the salivary secretions from the Parotid glands.
Watery (Serous) = Contains proteins (enzymes e.g Amylase)
Describe the salivary secretions from the Submaxillary glands.
Mixed serous and mucous secretion (thicker substance)
-Makes up 70% of secretions in the mouth
Describe the salivary secretions from the Sublingual glands.
Mucous (mainly)
What is the composition of saliva and what are their functions?
99% is water + complex mixture:
-Mucous
-Iron
-Growth factors
-Amylase (starch breakdown)
-Lysozyme (anti-bacterial)
-Bicarbonate (pH buffer)
-IgA (anti-bacterial)
-Epidermal growth factor (EGF) (Maintain tissue integrity
What are the 3 stages of stimulating gastric secretion?
Cephalic, Gastric and Intestinal phases
Describe the Cephalic stage of stimulating gastric secretion.
Sign of food/thought –>Cerebral Cortex–>Hypothalamus and Medulla Oblongata–>Vagus Nerve –> Stimulates gastric secretions
Describe the Cephalic stage of stimulating gastric secretion during Depression / Loss of Apetite.
Depression –> Cerebral cortex –> Lack parasympathetic stimulus –> Inhibits secretory activity
Describe the stages of Gastric secretion.
1.Gastrin secreted by G-cells
2.Mechanosensation upon stomach distension (just eaten)–>Parasympathetic signalling via Acetylcholine –>Secretion
What factors can stimulate gastric secretion?
Coffee, Peptides, Increase in pH
What is the Enterogastric reflex?
A feedback mechanism to control the rate of chyme emptying from the stomach into the small intestine. Stretching of the duodenal wall results in the inhibition of gastric motility and reduces the emptying of the stomach.
What hormone does the intestines produce to counter the acid from the stomach (HCL)?
Secretin
What do the duodenal glands produce and why?
Bicarbonate rich mucous for buffering
How long does it take till chyme is emptied from the stomach? (Note what order)
2-4 hours
1.Carbohydrates (fastest)
2.Protein
3.Fat (slowest: up to 6hrs)
How does the stomach protect / counter itself against the highly acidic enviroment?
-Bicarbonate mucous barrier
-Gastric pits with stem cells replace dead cells
-Stomach is COMPLETELY REPLACED: Every 3-6days
What digestive enzymes does the pancreas secrete?
-Bicarb
-Proteases (Typsinogen, Chymotrypsinogen, Elastase, Procarboxypeptidase)
-Pancreatic Lipase
-Nucleases (to degrade nucleic acids)
-Amylase
What does secretin do in the duodenum?
Stimulates the ducts to release bicarb pancreatic juice to neutralise the HCl.
What 2 duodenum hormones are secreted from the pancreas?
-Secretin
-Cholecystokinin (CCK)
What does CCK do in the duodenum?
Stimulates the Acini to secrete enzyme-rich pancreatic juice
What initiates Bile release?
CCK (Cholecystokinin)
What does Bile do in digestion?
Emulsifies lipids
How is Bile recycled?
Via Enterohaptic circulation
Where and when in bile stored?
In the Gallbladder between meals
Where are the majority of Carbohydrates and proteins absorbed?
Jejunum