5.2 Excretion Flashcards
Excretion
removing metabolic waste from your body (anything produced as a byproduct of a reaction)
Example of substance that needs to be excreted and how
co2 is excreted by breathing it out and nitrogen containing compounds like urea are excreted by the kidneys
Main excretory organs
Lungs, liver, kidneys, skin
Excretion w the liver
gets rid of toxins, plays big role in breaking down nitrogen containing compounds
Excretion w the kidney
Makes urine
Excretion w the skin
Sweat
Why’s excretion important
A build up of waste is toxic
What is the problem of excess co2 (not excreting co2)
it would combine w water to form carbonic acid and decrease the pH of your blood. Low pH would affect the proteins tertiary structure
Problem if not excreting nitrogenous compounds
amino acids are toxic so they’re broken down into something less toxic and less soluble = urea
Liver diagram
Portal triad
Hepatic portal vein, hepatic artery, bile duct at each lobule
Hepatic portal vein
brings deoxygenated blood from your digestive system.
Main function of liver
detoxification, clean blood
What is the liver divided into
Lobules
How are sinusoids formed
Hepatic portal vein and the hepatic artery enter the liver lobules they mix to form the sinusoid
What is the sinusoid lined w
Liver cells
What can be found inside the sinusoid
kupffer cells which are specialised macrophages
Hepatocytes
Liver cells
Hepatic artery
Bring in oxygenated blood
Hepatic portal vein
Brings deoxygenated blood rich in nutrients from the gut
Bile canaliculus
Bile flows from here to the bile duct
Sinusoid
Blood flows through here exchanging materials w endothelial cells and hepatocytes
Central vein
Blood flows from here into the hepatic vein
Liver lobule diagram
What do kupffer cells do to red blood cells
After 120 days, break down red blood cells bc they don’t have a nucleus so they can’t carry out protein synthesis
What causes change in the colour of a bruise
Haemoglobin changes colour
How would the blood entering the vein be clean
- By the time the blood travels through the sinusoid into your hepatic vein, hepatocytes would have worked to clean the blood so the blood entering the vein should be clean = no toxins
Where does the bile canaliculus take bile
drains into bile duct and bile can then go to digestive system or if your not eating anything the bile can be stored in the gallbladder
Bile
the breakdown products of red blood cell. RBC’S form bilirubin
Function of bile
Break down fat
Arrangement of cells in a lobule diagram
Intra-lobular vessel
If vessel is inside the lobule
Inter-lobular vessel
If the vessel is outside the lobule
Excretion (simplified)
removal of metabolic waste (digested) e.g. urea + co2
Egestion
removal of un digested waste that hasn’t entered the body
Where are liver cell receptors found
On every cell except red blood cells
HBA1C
The concentration of HbA1C is directly proportional to the mean concentration of glucose in the blood over an eight to twelve week period.
Functions of liver
- controls blood glucose levels bc it stores glucose as glycogen
- Synthesis of bile, cholesterol
- Synthesis of red blood cells in foetus
- Storage of vitamins (A,D) + minerals
- Detoxification of alcohol and drugs = as alcohol stays in the body is causes more damage since oh group is polar
- Breakdown of hormones
- Destruction of red blood cells
- Makes cholesterol from acytl co A = regulates fluidity of membrane + stores iron, copper, vitamins a,d
- Liver makes bile which makes fat globule into smaller fat droplets which makes it easier for
- Liver breaks down hydrogen peroxide using catalase.
Where does detoxification happen
On surface of smooth SER
Two key enzymes in detoxification
Catalase and cytochrome P450
Catalase
Breaks down hydrogen peroxide into oxygen and water
Cytochrome p450
Breaks down drugs
Alcohol
Ethanol
NAD
Coenzyme for the dehydrogenase enzyme = don’t have unlimited supply
Detoxification of alcohol
What else is NAD used for and what is this issue of running out of NADs
used in breakdown of fatty acids so if someone drinks too much alcohol they run out of NADs so fatty acids can’t be broken down = build up + leads to fatty liver
Formation of urea
Deamination
Keto acid
- can be used in respiration to yield energy (are respired). Keto acids can be converted to lipids and cholesterol
why can’t ammonia be transported in the blood
Highly toxic, highly soluble
Ornithine cycle
Why’s ammonia converted to urea
- urea is less soluble and less toxic than ammonia so it can be transported in the blood to the kidneys to be excreted
How does alcohol cause damage
breaks down phospholipid bilayer which damages the hepatocytes
Liver cells adaptions
Lots of mitochondria and endoplasmic reticulum
Why do liver cells have lots of mitochondria
to produce atp bc v huge metabolic role
Why do liver cells have lots of endoplasmic reticulum
To synthesise proteins and lipids
Kidney functions
- removal of waste products in the blood
- Controls water levels
- Osmoregulation
Functional unit of livers
Hepatocytes
Functional unit of kidneys
Nephron
How does everything move through the kidney
goes thru pelvis, into the ureter + passes out the body by the urethra
Kidney diagram
Nephron diagram
Stages of movement through the kidney
Ultrafiltration
Selective re absorption
Loop of henle
Distal convoluted tubule
Collecting duct