Circulation Flashcards
What are the features of a mass transport system?
System of vessels that carry substances
A way of making sure the substances are moved in the right direction
Means of moving the substances fast enough
A transport medium
What are the two types of circulation systems?
Single system
Double system
Closed system
Where are closed circulation systems found?
Insects
Where are single circulation systems found?
Fish
What is a single circulation system?
The heart pumps blood to the organs of gas exchange and the blood travels around the body and back to the heart
Why do more complex animals need a double circulation system?
They must maintain body tempreture which uses oxygen from the blood so need a more effecitve system
What is a double circulation system?
It involves two circulatory systems, one to take blood to the lungs and a second to take it around the body
What are the two systems of the double circulation system?
Systemic circulation
Pulmonary circulation
What is systemic circulation?
Oxygenated blood is carried from the heart around the body where the oxygen is used
Deoxygenated blood is then taken back to the heart
What is pulmonary circulation?
Deoxygenated blood is carried to the lungs where it gains oxygen and is taken back to the heart.
What are the advantages of the double circulation system?
The blood does not mix do the tissues get as much oxygen as possible
Can be delivered quickly at high pressure
What is the role of plasma?
Transporting glucose, amino acids, excretory products like CO2, chemical messages
What is the role of erythrocytes?
Transporting oxygen to cell from the lungs
How is haemoglobin adapted for it’s function?
Biconcave shape for a large surface area
No nucleus
What is the function of leucocytes?
To defend the body against infection
What are the two main types of leucocytes?
Granulocytes
Agranulocytes
What are granulocytes?
A type of leucocyte with granules in their cytoplams and lobed nuclei
What are the different types of granulocytes?
Neutrophils
Eosinophils
Basophils
What are neutrophils?
A type of leucocyte that is part of the non-specific immune response. They use phagocytosis
What are eosinophils?
A type of leucocyte that is part of the non-specific immune response. They are important in allergic reactions and developing immunity
What are basophils?
A type of leucocyte that is part of the non-specific immune response. They produce histamines and are involved in inflammation and allergic reactions
What are agranulocytes?
They are a type of leucocyte without granules in their cytoplasm and have unlobed nuclei
What are the different types of agranulocytes?
Monocytes
Lymphocytes
What are monocytes?
Part of the specific immune response and engulf pathogens by phagocytosis
What are lymphocytes?
Small leucocytes with large nuclei important in the specific immune response
What is the role of platelets?
Involved in blood clotting
What is the structure of haemoglobin?
Globular protein with 4 polypeptide chains which can pick up 4 oxygen molocules
What is the oxygen disassociation curve?
Describes the relationship between partial pressure and the saturation with oxygen
Describe the oxygen diassociation curve
The first oxygen molocule alters the haemoglobin and makes it easier for the next 2 to bind without a massive increase in partical pressure. The last is hard to bind because the liklihood of collision is low so an increase in pressure is needed
What does it mean when haemoglobin has a high affinity for oxygen?
A small change in partial pressure has a big effect
It’s more likely to bind
What is the Bohr effect?
The effect where a rise in CO2 lowers the oxygen affinity of haemoglobin
How is the affinity of haemoglobin affected by high CO2 partial pressure?
It’s lowered so it gives up oxygen more easily
How does faetal haemoglobin become oxygenated?
Oxygenated blood from the mother runs to the placenta and flows close to the deoxygenated faetal blood. As fetal hemoglobin has a higher affinity for oxygen, it transferrs across
What is the difference between myoglobin and haemoglobin?
Myoglobin has a higher affinity for oxygen but doesn’t release it easily so acts as an oxygen store
How is CO2 transported around the body?
5% carried in the plasma
10-20% combines with haemoglobin to form carbaminohaemoglobin
The rest is transported in the cytoplasm of red blood cells
How is serotonin and thromboplastin released as part of clotting?
Contacts between platelets and damaged tissues causes platelets to release them
What is the role of serotonin in the clotting cascade?
The blood vessel contracts and cuts of blood to the damaged area
What is the role of thromboplastin in the clotting cascade?
It catalyses the conversion of prothombin into thrombin
What is the role of thrombin in the clotting cascade?
It catalyses the conversion of fibrinogen into fibrin
What is the clotting cascade?
Thromboplastin converts prothrombin into thrombin
Thrombin converts fibrinogen into fibrin
Platelets get trapped in a fibrin mesh and form a clot
Proteins contract and form a scab
What are arteries?
They carry blood away from the heart towards the cells of the body, almost every artery carries oxygenated blood
Which two arteries carry deoxygenated blood?
Pulmonary artery: carries blood from the heart to the lungs
Umbilical artery: carries blood from the fetus to the placenta
What is the lumen?
The central space inside a blood vessel
What is the structure of an artery?
Small lumen
Middle layers contain elastic fibres
Why do arteries have elastic fibres?
The heartbeat sends blood out at high pressure so the arteries must be flexiable enough to widthstand the pressure surges
What is the difference between the major and peripheral arteries?
The lumen is smaller and there are less elastic fibres in the peripheral arteries because blood pressure drops the further away from the heart you are
What are capillaries?
Small blood vessels spread throughout tissues in the body where blood runs slowly so there is more time for diffusion
What are veins?
They carry blood back towards the heart, mainly deoxygenated
What is the structure of a vein?
Large lumen
Few elastic fibres
What are the two largest veins?
Superiour and inferiour vena cava
What are semi-lunar valves?
Valves that prevent the backflow of blood
What happens on the right side of the heart?
It gets blood from the body and pumps it to the lungs
What happens on the left side of the heart?
It gets blood from the lungs and pumps it around the body
What seperates the left and right sides of the heart?
Septum
Where is the first place blood from the body is delivered to in the heart?
The right atrium
Where is the tricupsid valve located?
Between the right atrium and right ventricle
How does the right ventricle fill with blood?
The right atrium contracts
What happens when the right ventricle contracts?
Blood is forced into the pulmonary artery and carried to the lungs
How does blood return to the heart from the veins?
Pulmonary veins
Where does the blood go when it comes back from the lungs?
The left atrium
Where is the bicupsid valve located?
Between the left atrium and left ventricle
Where does the blood go when the left ventricle contracts?
The aorta
What is a systole?
A contraction of the heart
What is a distole?
Where the heart relaxes and fills with blood
How do electrical impulses control the heartbeat?
Sinoatrial node sends a wave of depolarisation that causes the atria to contract
The annulus fibrosus stops it getting to the ventricles so instead, the atrioventricular node is activated which sends a second wave of depolarisation to the bundle of His and the ventricles contract
What is the sinoatrial node?
A group of cells in the right atrium that sends out the first wave of depolarisation needed to cause a heartbeat
What is the annulus fibrosus?
An area of non-conducting tissue that seperatesthe atria from the ventricles so slows down the wave of depolarisation
What is the atrioventricular node?
A group of cells that are stimulated by a wave of depolarisation from the SAN and then transmits it’s own wave to the Bundle of His
What is the bundle of His?
A group of conducting fibres in the septum of the heart into the purkyne tissue
What is the purkyne tissue?
Conducting fibres that take an electrical impulse from the septum to the ventricles and cause them to contract
What is atherosclerosis?
A cardiovascular disease from the build-up of plaques inside the arteries
How do you develop atherosclerosis?
Damage to the artery wall leads to the formation of a plaque deposit which blocks the artery or decreases the size of the lumen
What effects can atherosclerosis have on health?
Aneurysms
Raised blood pressure
Heart disease
Strokes
How does atherosclerosis cause aneurysms?
The blocked artery causes a bottle neck of blood which causes the artery to split open
What are the non-modifyable risk factors for atherosclerosis?
Genes
Age
Sex
What are the modifyable risk factors for atherosclerosis?
Smoking Fitness Weight Stress Diet
What is ontonic pressure?
The tendency for water to move into capilaries by osmosis
How is ontonic pressure calculated?
The water potential inside the cappilary minus the water potential outside
Where is tissue fluid forced out of the capillaries?
Arterial end
Why is the tissue fluid forced out of the capillaries at the arterial end?
Hydrostatic pressure is higher than ontonic pressure
Where does tissue fluid re-enter the capillaries?
Venous end
Why does the tissue fluid come into the cappilaries at the venous end?
Hydrostatic pressure is lower than ontonic pressure
What causes the fall in hydrostatic pressure as you move through the capillaries?
Pressure from the pulse is lost
As tissue fluid moves out, the volume of blood decreases so pressure falls
How much of the tissue fluid is reabsobed into the blood?
90%
the remainng becomes lymph
Where is lymph returned to the blood?
The neck
What is the difference between lymph and tissue fluid?
Lymph has less nutrients and oxygen and higher levels of fatty acids
