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80 Cards in this Set
- Front
- Back
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How is blood pumped around the body? |
Blood is pumped in a closed circuit made up of the heart and blood vessels. |
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What does blood transport in mammals? |
- Oxygen (lungs → rest of body) - CO₂ (rest of body → lungs) - Nutrients (gut → rest of body) - Urea (liver → kidneys) - Hormones, antibodies, heat etc |
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Why don't simple unicellular organisms need a circulatory system? |
Unicellular organisms can rely on diffusion to exchange all necessary gases as they have a high surface area to volume ratio (Cell surface membrane is large enough to meet demands of oxygen) |
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Why do multicellular organisms need a transport system? |
Multicellular organisms have a lower surface area to volume ratio. Surface not large enough to supply all gases needed through diffusion Have special gas exchange organs + circulatory system to distribute nutrients and gases |
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What are the main functions of a circulatory system? |
(In animals) - to transport oxygen and nutrients around the body They have special gas exchange organs + circulatory system to distribute nutrients and gases |
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How is blood pumped in a single circulatory system? Example? |
Heart → gas exchange organ → rest of body Eg: Fish |
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How is blood pumped in a double circulatory system? Example? |
Heart → gas exchange organ → heart → body |
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Why are double circulatory systems more efficient than single systems? |
Because the heart pumps blood twice so higher pressures can be maintained. Blood travels quicker to organs |
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What happens to blood in a single system? |
Fish - blood looses pressure as it passes through gills. Then travels slowly to rest of organs |
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What are the 2 distinct parts to double circulation? |
- Pulmonary circulation - blood circulated through lungs ← oxygenated here - Systemic circulation - blood circulated through body where it unloads its oxygen |
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What does the human circulatory system consist of? |
1. Heart - pump 2. Blood vessels - carry blood around body 3. Blood - transport medium |
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What does pulmonary mean? |
Pulmonary - concerning the lungs |
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What does Cardiac mean? |
Cardiac - concerns the heart |
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What are the main parts of the Blood? |
- Red blood cells (Carry O₂ as oxyhaemoglobin) - Platelets (small fragments of cell 4 clots) - Plasma (cell types suspended in this liquid) - White Blood cells (defend against infection) |
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What % of blood is plasma? What is Plasma mainly made of? |
Plasma makes up 55% of blood Plasma is mostly made up of water (liquid part of blood) |
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What is the role of blood plasma? (NB: Plasma is a straw coloured liquid) |
Plasma carries all other parts of blood and transports substances dissolved within it around body |
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What are the main substances transported by plasma? |
- CO₂ dissolved in it (body tissues → lungs) - Glucose dissolved in it (→ body tissues - Urea, nutrients, hormones - distributes heat energy |
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What are Platelets? Where are they made? What do they do? |
Small fragments of cells, no nucleus suspended in blood. They are made in the bone marrow When blood vessel is damaged, platelets seal + clot wound Prevents loss of blood cells, prevents infection |
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How do Platelets help prevent infection ? |
- Prevent infection as they stop micro organisms entering the blood through the wound - Help clot and heal |
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Where are red blood cells made? What is the life span of a RBC? Where are RBC destroyed? How are they transported round the body? |
RBC made in bone marrow they have a life span of 100 days. They're destroyed in the spleen They're suspended in blood cells |
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What are the main adaptations of RBC ? |
- contain haemoglobin ( carry oxygen) - biconcave (efficient exchange of oxygen) - no nucleus (more haemoglobin) - high surface area to vol ratio (large diff. area) - thin surface membrane (short + easy diff. dist.) |
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What is haemoglobin? What does it do? How does it transport oxygen? |
A red chemical containing iron, found in RBC It helps red blood cells absorb oxygen In lungs - combines w/ oxygen (oxyhaemoglobin) Tissue - oxyh. breaks down to release oxygen which is taken up by cells |
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What is the word equation for formation of oxyhaemoglobin in the lungs? |
In high oxygen concentration (lungs) : haemoglobin + O₂ → oxyhaemoglobin |
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What is the word equation for the break down of oxyhameoglobin in body tissue ? |
In low oxygen concentration (tissues) : oxyhaemoglobin → haemoglobin + O₂ |
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What is the role of White blood cells? How are they transported around the body? |
WBC protect the body against infection from pathogens by: phagocytosis and antibody production They're suspended in blood plasma |
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What do Phagocytes do? (70% of WBC) |
Phagocytes ingest MO: 1. Change shape 2. Extend their cytoplasm (pseudopodia) 3. Surround + enclose MO in vacuole 4. Secrete enzymes that break down MO |
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What do Phagocytes look like? |
Phagocytes are larger cells w/ large spherical or lobed nucleus |
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How do Phagocytes cause swelling and redness? |
- Increase blood flow to area - Cause fluid to leak into damaged area |
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What do Lymphocytes do ? (25% of WBC) |
- These produce chemicals called antibodies - Antibodies are soluble proteins that pass into plasma - Antibodies recognise antigens on pathogen surface and stick to them |
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What is an antigen? |
Antigens are telltale chemical 'markers' on the surface of bacteria and viruses - They're recognisable to Antibodies |
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How do Antibodies destroy pathogens? |
- Stick them together (Phagocytes ingest easily) - 'Label' pathogen (more recognisable to Phag) - Cause bacterial cells to burst open - Neutralise toxins produced by pathogens |
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How do some lymphocytes make us immune? |
Some lymphocytes develop into memory cells that remain in the blood and reproduce antibodies to known pathogens (Immunity) |
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What do Arteries do? Which artery doesn't carry oxygenated blood? |
Arteries carry blood oxygenated blood heart → organs Blood pumped out by ventricles and puts high pressure on artery walls - PULMONARY ARTERY CARRIES DEOX. BLOOD |
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What are the adaptations of the artery? |
- Thick muscle fibres in wall (high pressure) - Elastic tissues to stretch / recoil (push blood) - Have a small lumen (high pressure) - Round shape - Protective collagen layer |
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What do Veins do? |
Veins carry deoxygenated blood organs → heart Venous blood has lower pressure than arteries - PULMONARY VEIN CARRIES OXY. BLOOD |
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What are the adaptations of veins? |
- Thin muscle fibres (low pressure blood) - Watch pocket valves to prevent back flow - Protective collagen layer - Off round shape (weak wall) - Large lumen (decreases effect of friction) |
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What do Capillaries do? |
Capillaries carry blood through organs - bring blood close to every respiring cell (gases and nutrients can be exchanged) |
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What are the adaptations of Capillaries? |
1. One cell thick wall (endothelial cells) 2. Lumen is width of 1 RBC (small diff. dist) 3. No muscle or elastic tissue 4. Can fit between cells (thin and small) |
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What happens in blood capillaries when they reach respiring tissue? |
- O₂, glucose, amino acids, water diffuse into cells - CO₂, water, waste products diffuse into capillary down a diffusion / concentration gradient |
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What type of muscle is the heart made up of? What are the special properties of this muscle? |
The heart is made up of Cardiac Muscle - Doesn't tire, contracts continually |
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How many chambers does the heart have? |
Heart has 4 chambers: x2 Atrium / a (Upper) x2 Ventricle/s (Lower) |
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Which chambers pump blood out of heart? Which chambers receive blood back into heart? |
Ventricles pump blood out of the heart Atrias receive blood back into the heart |
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How is Blood moved through the heart? What is this called? |
Blood is moved through the heart by a series of contractions and relaxations of cardiac muscle in the walls of the 4 chambers - Known as CARDIAC CYCLE |
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What is the term used to describe a contracting chamber? What is the term used to describe a relaxing chamber? |
Contracting - 'in systole' Relaxing - 'in diastole' |
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What is step 1 of the cardiac cycle? |
- Blood enters atria but can't go into ventricles as bicuspid (mitral) + tricuspid valves are closed |
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What is step 2 of the cardiac cycle? |
- Walls of atria contract → blood pressure raises - Bi/Tricuspid valves are forced open - Blood passes through Bi/Tri into ventricles |
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What is step 3 of the cardiac cycle? |
- Ventricles contract when full - Blood pressure in ventricles raises - Bi/Tricuspid valves close - Blood can't go back to atria |
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What is step 4 of the cardiac cycle? |
- Ventricles keep contracting → pressure inc. - Semi-lunar valves are forced open. (at base of aorta + pulmonary artery) - Blood goes into these arteries |
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Where does the Pulmonary artery go? Where does the Aorta go? |
Pulmonary artery carries blood to lungs Aorta branches off to carry blood around body |
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What is step 5 of the cardiac cycle? |
- Ventricles empty → high pressure in aorta +PA - Valves in these blood vessels close - Process repeats as atria fill with blood |
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Why is the left side of the heart bigger than the right side? |
Right ventricle only pumps blood to lungs Left ventricle pumps blood to all body LV - thicker cardiac muscle (needs more pressure) |
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How many types of valve does the heart have? |
a) x2 semilunar valves b) x2 atrioventricular valves (b = x1 bicuspid & x1 tricuspid ) |
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What do valves do? |
Valves ensure blood can only flow in 1 direction |
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How does the function of atrioventricular valves differ to semilunar valves? |
SL - prevents back flow from artery → ventricle AV - prevent back flow from ventricle → atrium |
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How is the heart divided into a left and right side? |
The septum divides heart into left + right ↑ Chambers separated by atrial septum ↓ Chambers separated by ventricular septum |
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Wy does cardiac muscle have it's own blood supply? |
Heart constantly beats - cells constantly respiring - Need constant supply of O₂ & glucose - Need constant removal of waste products |
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Which blood vessels supply heart tissue with blood? |
Coronary arteries supply heart tissue w/ blood |
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What is coronary heart disease ? |
CHD - is a build up of plaque inside the coronary arteries. - Build up is called atherosclerosis -Occurs over many years |
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What is plaque made of? |
Plaque is a waxy substance made of fatty deposits (atheroma) & cholesterol & other waste substances |
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How can plaque build up cause heart attacks / heart failure / irreg heart beat? (irreg beat = arrhythmias) |
Plaque build up can rupture + clot narrow coronary arteries This cuts off blood supply to parts of heart muscle and deprives region of oxygen (stops respiring) |
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What factors will increase chances of developing CHD? |
- Smoking - High blood pressure + cholesterol - Lack of regular exercise -Diabetes - Coronary thrombosis |
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What is the normal heart beat per min? |
Average heart beat = 70 bpm |
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How does exercise increase heart rate? |
- Exercise - respiring tissue needs more energy - Need more oxygen for aerobic respiration - Oxygen in blood must get there quicker - Heart rate + Stroke volume increase - Ventilation rate increases |
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Why does the HR, SR and VE slowly decrease ? |
Exercise done - need for extra oxygen and glucose decreases as respiration rate slows - Muscles still need to repay oxygen debt and remove lactic acid |
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How is heart rate controlled? |
Heart rate is controlled by nerves in cardiac centre of the brain |
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Why does heart rate increase when we're stressed? |
Stress initiates the fight or flight response. - Adrenalin hormone secreted form adrenal glands |
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Why does heart rate decrease when we sleep? |
Sleeping - organs are working more slowly so less energy needs to be released - less oxygen needs to reach them |
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How are changes in heart rate brought about ? |
1) Cardiac centre in medulla of brain receives information about circulatory system 2) it changes heart rate according to activity level |
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What muscle cell in the heart controls heart rate?
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The pacemaker is a group of specialised muscle cell in the top right atrium. It receives 2 sets of nerve impulses from cardiac centre (1 increases other decreases) |
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Which factors cause a rise in heart rate? |
- Fall in blood pressure - Reduced oxygen concentration - Increased CO₂ concentration - Presence of Adrenalin hormone |
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What does the Aorta do? |
Delivers oxygenated blood, at high pressure, to body tissue. Has thick, muscular, elastic wall, no valves |
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What does the Vena Carva do? |
Main vein of body that returns deox. blood at low pressure from organs + tissues → heart |
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What does the Renal vein do? |
Returns blood w/ reduced urea concentration to circulation |
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What does the Renal artery do? |
Delivers oxygenated blood w/ high concentration of urea to the kidneys |
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What do the Kidneys do? |
Filter blood to remove waste Control body's water content |
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What does the Hepatic artery do? |
Carries oxygenated blood to liver |
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What does the liver do? |
Regulates composition of blood before it enters circulation |
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What does the Hepatic vein do? |
Delivers blood w/ regulated optimum concentration of food substances to circulation |
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What does the Hepatic portal vein do? |
Carries blood containing variable amounts of absorbed products of digestion from gut→liver |
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What does the Gut do? |
Digests food + transfers digested products to blood |
