Animal Transport 2 (Blood vessels, Tissue Fluid and Dissociation Curves) Flashcards
Name three substances that can pass through capillary walls
water, oxygen, carbon dioxide, urea, glucose, uric acid, lactic acid
What level of protein structure is shown in haemoglobin?
quaternary structure- 4 polypeptide chains, each one with a haem group
The heme groups in haemoglobin are an example of a ______ group
Prosthetic group
Describe how red blood cell shape is ideal for their function
biconcave, optimizes the ratio of surface area to volume, facilitating gas exchange. It also enables them to fold up as they move through narrow blood vessels.
What type of tissue is blood?
blood is considered part of connective tissue
What is the structure of an artery? (Include the layers)
Tunica externa on outside, made of collagen. Tunica media made of smooth muscle and elastic tissue. Tunica interna/intima on inside, consisting of squamous endothelial cells that are smooth to reduce friction
How does the structure of a vein differ from an artery?
The wall has the same layers but is overall thinner as they do not have to withstand high pressure. Veins also have semi-lunar valves to ensure flow in one direction
Why do arteries need thick walls?
To resist the high hydrostatic pressure
Which blood vessels can alter their diamater to increase or decrease blood flow and what is this called?
Arterioles. Vasoconstriction and vasodilation
Give four reasons pressure drops in capillaries
Blood is spread over a larger cross sectional area. Fluid leaves the capillaries through pores. There is increased friction with the walls. Blood is further from the heart.
List three things that help veins return blood to the heart despite having lower pressure than arteries
Gravity (from above heart), massaging action of skeletal muscle, negative pressure in thorax during inspiration
What are the X and Y axes of an oxyhaemoglobin dissociation curve?
X partial pressure O2 (PPO2) Y % saturation of haemoglobin with oxygen
What are the proper terms for haemoglobin binding to and releasing oxygen?
Associating and dissociating
What is the proper term for haemoglobin’s level of attraction to oxygen?
Affinity
How does foetal haemoglobin differ from adult haemoglobin?
It has a higher affinity for oxygen, meaning it can associate oxygen at lower PPO2s and will be fully saturated at a lower PPO2 than adult haemoglobin. It will not dissociate until very low PPO2. Curve shifted to left
How do llama and lugworm haemoglobins differ from human haemoglobin?
Their haemoglobin has a higher affinity for oxygen due to living in areas of lower oxygen, meaning their haemoglobin can associate oxygen at lower PPO2s and will be fully saturated at a lower PPO2 than human haemoglobin. Their haemoglobin will not dissociate oxygen until very low PPO2. Curve shifted to left
What happens to human blood when living at altitude?
More red blood cells are produced
What is cooperative binding of haemoglobin?
When the first O2 molecule binds with one haem group it changes the shape of the haemoglobin molecule, making it easier for the second molecule to attach. The 4th O2 molecule only attaches if there is a very large increase in ppO2
What happens to the oxyhaemoglobin dissociation curve when CO2 increases (/pH falls)?
The Bohr shift- curve shifts to the right. Haemoglobin is less saturated with oxygen at any partial pressure of oxygen. More oxygen is dissociated from haemoglobin for use by respiring tissues
What are the three ways CO2 is transported back to the lungs in the blood?
5% dissolved in plasma, 10% combined with haemoglobin to form carbaminohaemoglobin, 85% as hydrogen carbonate ions (HCO3-)
What happens to CO2 when it dissolves in water? And which enzyme speeds up this reaction in red blood cells
It dissolves to form carbonic acid CO2 + H2O-> H2CO3- this reaction is catalysed by carbonic anhydrase
What happens to carbonic acid in a red blood cell?
It is unstable and dissociates into hydrogen ions and hydrogen carbonate ions (H+ and HCO3-). HCO3- ions diffuse out of the red blood cell into the plasma
Why do chloride ions diffuse into a red blood cells?
To maintain the charge when HCO3- ions leave. This is called the chloride shift.
What happens to the H+ ions produced in a red blood cell from carbonic acid?
They bind to haemoglobin, forming haemoglobinic acid. Haemoglobin acts as a buffer and dissociates oxygen molecules to bind to the H+
Why does fluid leave the capillary at the arterial end? Hint talk about pressure
Hydrostatic pressure pushing fluid out of the capillary is higher than osmotic pressure drawing fluid back in
Why does fluid return to the capillary at the venous end? Hint talk about pressure
Hydrostatic pressure pushing fluid out of the capillary is lower than osmotic pressure drawing fluid back in. This is because hydrostatic pressure drops as blood moves along the artery
List the components of blood too large to leave the capillary through the pores
Large plasma proteins and red blood cells
What is the function of tissue fluid?
To bathe the cells, providing them with oxygen and nutrients
What happens to excess tissue fluid that does not return to the capillary?
It drains into the lymphatic system, becoming lymph. Lymph to the blood stream via the subclavian vein in the neck
