4.3 Flashcards
circulation
what is a mass transport system
substances are transported in the flow of a fluid with a mechanism for moving it around the body
what is an open circulatory system
blood circulates in large open spaces
what is a single circulatory system
heart pumps deoxygenated blood to the site of gas exchange (gills) where the blood becomes oxygenated then travels around the rest of the body
what is a double circulatory system
the pulmonary circulation carries deoxygenated blood from the heart to the lungs to be oxygenated then back to the heart so that the systemic circulation can carry oxygenated blood around the body then return to the heart
what are the advantages of the double circulatory system
oxygenated and deoxygenated blood cannot mix so tissues receive much more oxygen
fully oxygenated blood can be delivered quickly to the body tissues at high pressure
define circulation
the passage of blood through the blood vessels
what is the role of the plasma
transport of:
digested food products from small intestine to the entire body
nutrient molecules
excretory products
chemical messengers
and maintains steady body temperature
acts as a pH buffer
how does the plasma maintain the body’s temperature
transfers heat around the system from deep-seated organs and active tissues to the rest of the body
what is haemoglobin
red pigments that carries oxygen and give erythrocytes their colour
how are red blood cells well adapted
do not contain a nucleus to make space for haemoglobin
biconcave disc shape to increase sa:v for faster diffusion of oxygen
transports
what are leucocytes and their general adaptations
cells which defend the body against infection
larger than erythrocytes
can change shape to squeeze through tiny blood vessels
contain a nucleus
have a colourless cytoplasm
some contain granules that can be stained
what are the 3 granulocytes
neutrophils
eosinophils
basophils
what are the 2 agranulocytes
monocytes
lymphocytes
what are the general adaptations of granulocytes
contain granules in the cytoplasm
take up stain so they are obvious under a microscope
have a lobed nucleus
what is the specific role of neutrophils
non-specific immune system
engulf and digest pathogens by phagocytosis
multi-lobed nucleus
most common leucocyte
what is the specific role of eosinophils
non-specific immune system
stained by eosin stain
respond to parasites, allergic reactions and inflammation
what is the specific role of basophils
non-specific immune response
two-lobed nucleus
produce histamines involved in reducing inflammation and allergic reactions
what are the general adaptations of agranulocytes
do not have granules
unlobed nucleus
what is the specific role of monocytes
specific immune system
largest leucocyte
can move out of the blood into tissues to form macrophages which engulf pathogens by phagocytosis
what is the specific role of lymphocytes
specific immune response
very small
large nucleus
what is the role of platelets
involved in the clotting mechanism of the blood
what are megakaryocytes
large cells found in the bone marrow and produce platelets
what is the structure of haemoglobin
large globular protein
4 peptide chains
iron-containing prosthetic groups
quaternary structure
can hold 4 molecules of oxygen to form oxyhaemoglobin
how does oxygen leave a red blood cell
the red blood cell contains a higher concentration of oxygen in the cytoplasm than surrounding tissue therefor oxygen moves out by diffusion down the concentration gradient
why is it important that haemoglobin has a high affinity for oxygen
so that small changes in the proportion of oxygen in the surroundings can have a big effect on saturation of the blood with oxygen
what is the relationship between CO2 partial pressure and affinity of haemoglobin
as CO2 partial pressure increases affinity of haemoglobin reduces
what is the bohr effect
changes in the oxygen dissociation curve of haemoglobin that occur due to rise in CO2 levels and a reduction in the affinity of of haemoglobin for oxugen
what is fetal haemoglobin and how is it adapted for oxygen transfer
only found in developing fetus
has a higher a higher affinity for oxygen than the mothers haemoglobin so when blood runs through the placenta oxygen is transferred to the fetus and a counter current system is used to maximise gas exchange across the entire length of the placenta
what is myglobin and its role
small bright red protein found in muscle tissue of vertebrates giving meat a strong red colour
it has a high affinity for oxygen and is not easily affected by the partial pressure of oxygen therefor acts as a store for oxygen as it is not easily released
what is carbaminohaemoglobin
the compound formed when waste carbon dioxide binds with haemoglobin
what are the 3 ways waste carbon dioxide is removed
carried in plasma
binds with haemoglobin
transported in cytoplasm of red blood cells as hydrogen carbonate ions
what is the role of carbonic anhydrase
controls rate of reaction between carbondioxide and water forming carbonic acid
what is the equation for the hydration of carbondioxide and its dissociation
CO2 + H2O <=> H2CO3 <=> HCO3- + H+
how is the pH of the blood controlled as carbondioxides dissolve and form carbonic acid
the heamoglobin acts as a buffer accepting hydrogen ions to form haemoglobinic acid
what is the need for blood clotting
seals up damaged blood vessels to minimise blood loss
prevents pathogens getting in
how do platelets start the formation of a clot when someone has a cut
when the platelets come into contact with components of the tissue (e.g. collogen fibers of skin) they break open and release serotonin and thromboplastin
what does serotonin do
causes the smooth of the blood vessels to contract therefor narrowing blood vessels and cutting off blood flow to the damaged area
what do thromboplastins do
sets into motion the blood clotting cascade
what is the blood clotting cascade
thromboplastins catalyse production of thrombin from prothrombin which requires calcium ions
thrombin then converts fibrinogen to fibrin which forms a mesh of fibres that cover the wound
more platelets and blood cells become trapped in the mesh
proteins in the platelets contract tigthning the clot forming a scab for protection while the vessels underneath heals
define arteries
vessels that carry blood away from the heart
define veins
vessels that carry blood towards the heart
define capillaries
small vessels that spread throughout the tissues of the body where most substances carried by the blood is exchanged into cells
what is the pulmonary artery
carried deoxygenated blood away from the heart towards the lungs
what is the umbilical artery
carries deoxygenated blood from the fetus to the placenta