Transport (humans) Flashcards
What are the four things blood consists of?
Red blood cells, white blood cells, platelets and plasma
What percentage of the total volume of blood does each of the four things make up?
Red blood cells: 45%
Plasma: 55%
Platelets and white blood cells: <1%
What is plasma?
A straw coloured liquid in which other components of blood are suspended in
It is also what all other substances transported by the blood and suspended in, and it is necessary to transport these substances around the body
Which substances are transported in blood plasma?
Carbon dioxide
Digested nutrients (including mineral ions)
Urea
Hormones
Heat energy
Oxygen is carried in the red blood cells, not plasma
Plasma is comprised of 90% water, so it also carries water
What are the adaptations of red blood cells that make them suitable for the transportation of oxygen?
They are full of haemoglobin, a protein which binds to oxygen
They have no nucleus to allow for more space for haemoglobin
They are small and have a bioconvave disk shape which allows them to have a small surface area to volume ratio for optimal diffusion
What is the pathway of blood through the heart?
Vena Cava
Right atrium
Tricuspid valve
Right ventricle
Semilunar valve
Pulmonary artery
Lungs (oxygenated)
Pulmonary vein
Left atrium
Bicuspid valve
Left ventricle
Semilunar Valve
Aorta
Why are there thicker muscular walls on the left ventricle of the heart?
It must pump blood a much further distance (around the whole body) at a high pressure, compared to the right ventricle which only needs to pump it to the lungs
What are valves for in the heart?
Preventing backflow
What is the septum for in the heart?
Dividing the right and left ventricle and stopping the oxygenated and deoxygenated blood from mixing, which could cause blood being pumped to the rest of the body to be less oxygenated
What happens to heartrate during exercise and why?
It increases
More muscular contractions lead to increased need for respiration
More glucose and oxygen must be supplied, and more carbon dioxide (and potentially lactic acid) must be removed due to increased respiration
What happens to heartrate under the influence of adrenaline and why?
It increases as more blood with oxygen and glucose is pumped to the muscles in preparation for running/fighting
What are the factors that increase the risk of developing coronary heart disease?
Obesity - Extra weight puts strain on heart, and if the person has diabetes, this can damage blood vessels
High blood pressure - Increases force of blood against vessels, damaging them
High saturated fat/cholesterol diet - Is what causes the build up of fatty plaques
Smoking - Can contribute to plaque build up and increase blood pressure, carbon monoxide can also reduce oxygen carrying capacity, nicotine increases blood pressure
Lack of exercise - Exercise makes heart and circulation better and more efficient and reduces cholesterol and blood pressure
What are the distinct features of arteries?
Carry blood away from the heart
Have a thick muscular and elastic wall to carry blood at high pressure
Have a small lumen to maintain a high pressure
Carry oxygenated blood, apart from the pulmonary artery
Have connective tissue which provides strength
The blood is under high pressure in the arteries because it has just been pumped out of the left ventricle at extreme force
Arterioles are the smaller arties which branch off of arteries
What are the distinct features of veins?
Carry blood towards the heart
Have less muscular, elastic and connective tissue as blood is being carried at lower pressures (as it has not just been pumped out the left ventricle)
Have a large lumen to allow blood to flow at low pressures
Carry deoxygenated blood, apart from the pulmonary vein
Have valves to stop the backflow of blood
They need valves because the blood is at a low enough pressure for backflow to occur
What are the distinct features of capillaries?
Very small to allow them and the blood they are carrying to get up close to organs
Capillary walls are one cell thick and permeable to allow for easy diffusion
What do Phagocytes do?
Phagocytes carry out phagocytosis by engulfing and digesting pathogens
How do Phagocytes work?
Phagocytes have a sensitive cell surface membrane that can detect chemicals produced by pathogenic cells
Once they encounter the pathogenic cell, they will engulf it and release digestive enzymes to digest it
This is a non-specific immune response
What do Lymphocytes do?
Lymphocytes produce antibodies and antitoxins
What are antibodies?
Antibodies are Y-shaped proteins with a shape that is specific (complementary) to the antigens on the surface of the pathogen
This is a specific type of immune response
How do antibodies work?
Antibodies attach to the antigens and cause agglutination (clumping together)
This means the pathogenic cells cannot move very easily
At the same time, chemicals are released that signal to phagocytes that there are cells present that need to be destroyed
What is Immunity?
Once a pathogen has entered the body the role of the immune system is to prevent the infectious organism from reproducing and to destroy it
An organism has immunity when they have sufficient levels of antibodies to protect it from a particular disease
Describe the immune systems response to an infection
pathogen enters the blood stream and multiplies
release of toxins and infection of body cells causes symptoms
Phagocytes encounter the pathogen, recognise it is an invading pathogen and engulf and digest
the pathogen encounters a lymphocyte which recognises its antigens
The lymphocyte starts to produce specific antibodies
The lymphocyte also clones itself to produce lots of lymphocytes (to produce that antibody)
Antibodies cause agglutination of pathogens
Phagocytes engulf and digest the agglutinated pathogens
After recovery, they retain antibodies specific to the disease as well as memory cells
If the patient encounters the same pathogen again, it will trigger a secondary immune response
Memory cells can produce much larger quantities of the required antibody in a much shorter time to fight off the pathogen before the patient suffers any symptoms
What are vaccines?
Vaccines are used to induce immunity to infectious diseases
A vaccine contains harmless versions of a pathogen
How do vaccines work?
Once in the bloodstream, the antigens contained within the vaccine can trigger an immune response
Lymphocytes recognise the antigens, so produce antibodies thus creating memory cells
Future infection by the same pathogen will trigger a response that is much faster and much larger
What are platelets?
Platelets are involved in helping the blood clot
Platelets are fragments of cells that are involved in blood clotting and forming scabs where the skin has been cut or punctured
How do platelets work?
When the skin is broken, platelets arrive to stop the bleeding
reactions occur within the plasma
Platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin and form an insoluble mesh across the wound, trapping red blood cells and therefore forming a clot
The clot eventually dries and develops into a scab to protect the wound from bacteria entering
Where does oxygenated blood enter and exit the heart?
Enters the left Atrium via the Pulmonary Veins
Pumped to the Body via the Aorta
Where does deoxygenated blood enter and exit the heart?
Enters right atrium by vena cava
Exits right ventricle to lungs by pulmonary vein
What separates the sides of the heart?
A muscle called the septum
What do coronary arteries do?
supply the cardiac muscle tissue of the heart with oxygenated blood
the heart is a muscle it needs a constant supply of oxygen (and glucose) for aerobic respiration
What do valves do?
Prevent blood flowing backwards
What is the pacemaker?
A group of cells in the right atrium
They coordinate the contractions of the heart
Does this by sending out electrical impulses
What role does the heart play during exercise?
The heart pumps blood around the body in order to supply oxygen and glucose to respiring cells
The blood also removes waste products from the respiring cells
What two ways does the nervous system respond to increase in respiration during exercise?
Increase in Heart rate
Volume of blood pumped
What hormone is released during exercise?
Adrenaline, it increases heart rate
What happens after exercise?
the heart rate may remain high for a period of time
because oxygen is required in the muscles to break down the lactic acid from anaerobic respiration
This is how the oxygen debt is paid off
What is CHD?
Coronary Heart disease
It is where layers of fatty material (plaque) build up inside the coronary arteries
These fatty deposits are mainly formed from cholesterol
If a coronary artery becomes partially or completely blocked by these fatty deposits, it loses its elasticity and cannot stretch to accommodate the blood which is being forced through every time the heart contracts
What are the results of CHD?
Partial blockage of the coronary arteries creates a restricted blood flow to the cardiac muscle cells and results in severe chest pains called angina
Complete blockage means cells in that area of the heart will not be able to respire aerobically, leading to a heart attack
How do you treat CHD?
Treatment of CHD involves either increasing the width of the lumen of the coronary arteries using a stent, or prescribing statins to lower blood cholesterol
What risk factors can affect CHD?
Vein (venules)
Arteries (arterioles)
Capillaries
What Blood vessels go to and from the Heart?
Towards: Vena cava and Pulmonary vein
Away: Aorta and pulmonary artery
What Blood vessels go to and from the Lungs?
Toward: Pulmonary Artery
Away: Pulmonary vein
What Blood vessels go to and from the Kidneys?
Towards: Renal Artery
Away: Renal Vein
