5.2 Excretion Flashcards
What is excretion?
The removal of metabolic waste from the body
What are three excretory products?
Carbon dioxide, urea and bile pigments
What are the main four excretory organs?
Lungs, liver, kidneys and skin
What is the effect on the blood of an increase in carbon dioxide concentration?
Decrease in ph making the blood more acidic
What is the response to an increase in carbon dioxide concentration in the blood?
Increased breathing rate: The CO2 diffuses into the alveolis and is excreted from breathing out
What is the name for the basic functional unit of the liver?
Lobules
What is another name for liver cells?
Hepatocytes
What are the 4 vessels associated with the liver?
Hepatic vein, hepatic portal vein, hepatic artery and bile duct
Which liver vessel is intra-lobular? (Inside the lobule)
The hepatic vein
Which liver vessels are inter-lobular? (around the outside of the lobule)
The hepatic portal vein, hepatic artery and bile duct
What are the chambers in the lobules through which blood from the hepatic portal vein and hepatic artery pass?
Sinusoids
What are the chambers in the lobules through which bile is transported to the bile duct?
Canaliculi
What are the resident macrophages called in the liver?
Kupffer cells
What is the function of a Kupffer cell?
Break down and recycle old red blood cells
What are three functions of the liver?
- Carbohydrate metabolism
- Deamination of excess amino acids
- Detoxification
What is a metabolic reaction?
A reaction that takes place within the cell
How is CO2 made?
Produced by cells in the body in respiration
How many blood supplies does the liver have?
-Two, the hepatic artery and the hepatic portal vein
What is the purpose of the hepatic artery?
The hepatic artery brings oxygenated blood to the liver
What is the purpose of the hepatic portal vein?
-The hepatic portal vein brings nutrient rich blood to the liver from the gut
-The blood is rich in glucose, amino acids and fatty
acids
-This is because these nutrients are by-products of digestion that are absorbed in the small intestine (The gut) into the blood were it is carried to the liver
What does the liver do?
The liver regulates the concentrations of all these food or toxin molecules to avoid the concentrations of them from going straight into the blood stream when they could be to high or low
What are sinusoids
The channels between the rows of cells that lead to the intra-lobular vessel at the top
What does the inter-lobular vessel, the hepatic artery provide?
The hepatic artery brings blood containing oxygen needed for respiration and ATP production
What is the purpose of the inter-lobular vessel, the hepatic portal vein?
The hepatic portal vein brings varying levels of nutrients as well as toxins to the liver in the blood
What are the liver cells that surround the inter-lobular vessels called?
Hepatocytes
What is the functions of hepatocytes?
- Hepatocytes are chemical reaction cells meaning that they need oxygen as their job is active
- Hepatocytes take in chemicals for a reaction and then release the products of the reaction
- The hepatocytes are able to remove and insert nutrients into the sinusoids in order to regulate the levels of the nutrients
What are kupfer cells and where are they located?
- Kupffer cells are modified macrophages (white blood cells) that are found in sinusoids
- The function of these resident macrophages is to process dead red blood cells
- They take haemoglobin from these dead red blood cells and convert it into the product bilirubin
Where is the waste products that are removed by the hepatocytes moved to?
The toxic waste products are moved to the bile canaliculi
What does the inter-lobular vessel, the bile duct do?
The bile duct drains into the gall bladder which is full of bile that will later be emptied into the small intestine
Why is not all of the process of releasing faeces not considered excretion?
Only part of the process is excretion as bile is the only excretory product used, this is when the bile salts are added before the faeces is released
Why is faeces not an excretory product?
Faeces is not directly formed from the major organs responsible for excretion (The liver, kidneys, lungs and skin) therefore it is not a result of metabolic reactions inside the body
What is faeces made up of?
Faeces is the remains of food that was not digested in the small intestine
What happens to the bilirubin that is made from the haemoglobin in dead rbc’s?
The bilirubin is put into the bile canaliculi where it exits the bile