Topic 3 - Transport systems Flashcards
What’s the definition of digestion ?
Digestion and Absorption
Larger biological molecules are broken down into smaller molecules which can move across cell membranes and be absorbed from the gut into the bloodstream to body cells
How are carbohydrates broken down ?
Digestion and Absorption
Amylase hydrolyses startch into maltose during a hydrolysis recation by adding a water molecule, breaking the glyocosodoc bonds.
Membrane bound disachharidases hydrolyse maltose into glucose during a hydrolysis reaction which adds water to break the glycosidic bonds.
Where is amylase produced?
Digestion and Absorption
salivary glands (secreted into the mouth)
pancreas (secreted into the small intestine)
Where are membrane bound disacharidases found ?
Digestion and Absorption
the epithelial cells of the ileum
How are lipids broken down ?
Digestion and Absorption
lipase enzyme hydrolyses the ester bonds by the addition of a water molecule in a hydrolysis reaction between lipids to form monoglycerides and fatty acids.
Where are lipases produced and found ?
Digestion and Absorption
produced in the pancreas
found in the small intestine
Where are bile salts produced and stored ?
Digestion and Absorption
produced in the liver and stored in the gall bladder
How are micelles formed ?
Digestion and Absorption
once the lipid is brown down, the monoglycerided and fatty acids stick with the bile salts to form micelles.
Monoglycerides and fatty acids are not very soluble, so micelles aid the transport of these substances to the cell surface membrane.
What are the two main peptidases ?
Digestion and Absorption
endopeptidases
exopeptidases
What is the role of endopeptidases ?
Digestion and Absorption
They hydrolyse the peptide bonds within a protein to form smaller proteins.
What is the role of exopeptidases ?
Digestion and Absorption
They hydrolyse the peptide bonds at the end of the protein molecules. To inccrease the surface area for Dipeptidades.
What is the role of dipeptidases ?
Digestion and Absorption
Dipeptidades hydrolyse the peptide bond between 2 amino acids (dipeptide), they’re often located in the cell surface membranes of the epithelial cells of the small intestine.
How are monosaccharides absorbed ?
Digestion and Absorption
- Sodium ions are actively transported out of the ileum epithelial cells into the blood by the sodium potassium pump, this creates a concentration gradient as there’s a high concentration of sodium ions in the lumen compared to the epithelial cells.
- Sodium ions diffuse from the lumen into the epithelial cells down their concentration gradient via the co transporters
- The co transporters bonded to glucose/galactose and sodium, meaning that glucose molecule is carried into the cell causing the concentration of glucose in the epithelial cells to increase.
- glucose diffuses out of the cells into the blood stream down it’s concentration gradient in a protein channel by facilitated diffusion.
Fructose is absorbed via facilitated diffusion
How are amino acids absorbed ?
Digestion and Absorption
- Sodium ions are actively transported out of the ileum epithelial cells into the blood by the sodium potassium pump, this creates a concentration gradient as there’s a high concentration of sodium ions in the lumen compared to the epithelial cells.
- Sodium ions diffuse from the lumen into the epithelial cells down their concentration gradient via the co transporters
- The co transporters bonded to amino acids and sodium, meaning that amino acid molecule is carried into the cell causing the concentration of amino acid in the epithelial cells to increase.
- amino acids diffuses out of the cells into the blood stream down it’s concentration gradient by facilitated diffusion.
how are monoglycerides and fatty acids absorbed ?
Digestion and Absorption
micelles help move them into the epithelial cells where they’re transported to the ER and the golgi apparatus to be recombined and form triglycerides.
Triglycerides combine with cholesterol and lipoproteins to form chilomicrons.
chilomicrons move out of the cell by exocytosis and enter the lacteals of the villi.
What does blood transport ?
The Cardiac Cycle
Respiratory gases
products of digestion
metabolic waste
hormones
What is the function of the coronary arteries ?
The Cardiac Cycle
They supply the heart muscle with oxygenated blood and glucose
What is the pericardium ?
The Cardiac Cycle
It encloses the heart to protect it from over expansion and infection
What’s the pulmonary circuit ?
The Cardiac Cycle
Blood is pumped to the lungs to pick up oxygen
What is the systemic circuit ?
The Cardiac Cycle
oxygenated blood is pumped around the body
What are the walls of the heart made out of ?
The Cardiac Cycle
Cardiac muscle with doesn’t tire however it requires oxygen
What is systole ?
The Cardiac Cycle
contraction of heart muscles
What is diastole ?
The Cardiac Cycle
Relaxation of the heart muscles
Why do the ventricles have thicker muscles than the atria ?
The Cardiac Cycle
They pump blood across longer distances so the contraction needs to be stronger
What are the bicuspid and tricuspid valves ?
The Cardiac Cycle
They link the atria to the ventricles.
They close when there’s a higher pressure in the ventricles than the atria to prevent the backflow of blood from the ventricles into the atria.
They open when there’s a larger pressure in the atria than the ventricles to allow blood to flow through to the ventricles
What are the semi-lunar valves ?
The Cardiac Cycle
They are valves between the ventricles and the aorta and pulmonary artery.
They close when there’s a higher pressure in the atria than the ventricles to prevent the backflow of blood into the ventricles from the aorta and pulmonary artery
They open when there’s a higher pressure in the ventricles than the atria to allow blood to flow through the aorta and the pulmonary artery
What are the function of cords in relation to the heart ?
The Cardiac Cycle
They connect the atrioventricular valves to the ventricles to stop them from being forced into the atria during contraction
What are the 3 steps of the cardiac cycle ?
The Cardiac Cycle
atrial systole
ventricular systole
diastole
Explain what happens during atrial systole
The Cardiac Cycle
The muscles of the atria contract and the ventricles relax.
This decreases volume and increases pressure of the atria. This causes the bicuspid and tricuspid valves to open to allow blood to flow through to the ventricles. The semi-lunar valves close to prevent the back flow of blood from the aorta and pulmonary artery to the ventricles. Pressure decreases
What happens during ventricular systole ?
The Cardiac Cycle
The muscles of the ventricles contract and the atrial muscles relax. This decreases the volume and increases the pressure of the ventricles. This causes the bicuspid and tricuspid valves to close to prevent the back flow of blood from the ventricles to the atria. The semi-lunar valves open to allow blood to flow through the pulmonary artery and aorta
What happens during diastole ?
The Cardiac Cycle
the ventricles and atria both relax. The high pressure in the aorta and pulmonary artery causes the semi lunar valves to close to prevent the backflow of blood from the arteries to the ventricles. Blood flows to the body and lungs. Blood starts to flow through the vena cava and pulmonary vein.
What is the function of the arteries ?
The Cardiac Cycle
They transport blood to the rest of the body