TRANSPORT In Humans Flashcards
(24 cards)
LISTEN THE ADAPTATIONS of a red blood cell
1) it’s ‘biconcave disc’ shape: increases thes SA:V ratio , to maximise diffusion of oxygen in and out of the cell
2) full of protein: haemoglobin, which binds to oxygen to form oxyhaemoglobin- transports oxygen
3) no nucleus- more space for haemoglobin to be packed in
What are the components of the blood
Plasma (straw-coloured liquid): transports substances around the body
Red blood cells (biconcave-disc shaped cells with no nucleus) : transports oxygen around the body
White blood cells (larger cells with a nucleus) : defends the body against infection and pathogens
Platelets (fragments of cells) : prevents blood loss and pathogens entering through clotting up wounds
ROLE of LYMPHOCYTES:
LYMPHOCYTES are a type of white blood cell- they release antibodies which are protein ‘markers’ that are complementary to antigens found on pathogen surfaces
-a pathogen is detected by a lymphocyte and the lymphocyte begins producing antibodies complementary to the surface antigen
-the lymphocyte also multiplies to produce lots of specific antibodies
-antibodies stick to antigens which can destroy pathogens by:
1) marking them so that they can be more easily detected by phagocytes
2) sticks bacteria cells together to be more easily engulfed by phagocytes
3) neutralises toxins produced by pathogens
4)causes bacterial cells together burst open
ROLE of PHAGOCYTES:
Phagocytes are a type of white blood cell: they engulf and destroy microorganisms
1) the phagocyte’s sensitive cell membrane detects chemicals produced by the pathogen
2) the phagocyte produces extensions of their cytoplasm to surround and engulf the pathogen in a vacuole
3) digestive enzymes are secreted to break down the pathogen within the phagocyte
EXPLAIN IMMUNITY
1) sometimes lymphocytes turn into MEMORY CELLS
2- these stay in the blood for many years- sometimes a lifetime
3) when that microorganism re-infects the person, the MEMORY CELLS activate and produce antibodies rapidly
4) this destroys the microorganism quickly and effectively
5) we can call this the SECONDARY IMMUNE RESPONSE and it is much faster and more effective and kills the microorganism before it can multiply and cause disease
‘Agents’ used in vaccines
-dead microorganisms
-a weakened strain of the microorganism
-modified toxins of the bacteria
-just the antigens
VACCINATIONS
Vaccinations can be used to prevent disease or reduce the effect of a pathogen by giving artificial immunity to a person:
1) the person receives a harmless version of the pathogen, using an ‘agent’ which carries the specific antigens of the pathogen
2) LYMPHOCYTES in the blood then detect these antigens and produce antibodies that are complementary
3)These LYMPHCYTES turn into MEMORY CELLS which remain in the blood for many years and make the person ‘immune’
4) If the person comes into contact with the ‘real’ microorganism, the MEMORY CELLS activate and produce antibodies rapidly, at high levels to quickly destroy the pathogen and prevent it reproducing and causing disease
PLATELETS ROLE
PLATELETS ARE SMALL FRAGMENTS OF CELLS
-when there is a wound or cut on the skin,
2) exposure to air stimulates the platelets to release chemicals
3)these convert SOLUBLE FIBRINOGEN PROTEINS in the plasma into INSOLUBLE FIBRIN PROTEINS
4) these form an insoluble mesh which covers the wound and TRAPS red blood cells
5) forming a clot- which dries to form a SCAB
6)the SCAB covers the wound, preventing pathogens from entering the bloodstream + excessive blood loss - whilst new skin grows
EXPLAIN THE STAGES of the cardiac cycle
1) blood enters the atria and begins to fill it- the atrioventricular valves restrict it from entering the ventricles
2) the walls of the atria contract which increases the pressure of the blood, pushing it through the atrioventricular valves and into the ventricles.
3) when the ventricles are full, the ventricles contract, increasing pressure which closes teh atrioventricular valves
4)the ventricles continue to contract and pressure continues to increase, which forces the semi-lunar valves open and ejects the blood up into the arteries. The semi-lunar valves prevent the backflow of blood back into the ventricles
5) the aorta then carries the oxygenated blood across the body and the pulmonary artery carries deoxygenated blood to the lungs.
6) high pressure in the aorta and the pulmonary artery closes the semi-lunar valves and the cycle repeats again when blood enters the atria
List the heart adaptations:
-the walls of the left ventricle is much thicker than the walls of the right ventricle: the left ventricle has to pump blood at a high pressure across the whole body, whereas the right ventricle is only directing blood to the lungs- where it has to have a low pressure to prevent damage to the capillaries in the lungs.
- the walls of the atria are very thin because it receives blood
-the heart has its own coronary arteries
-the walls are made of cardiac muscle- which never become fatigued
-valves in the heart prevent backflow
-the two sides are separated by a wall of muscle called the SEPTUM
Why does our heart rate increase when we exercise?
1)when we exercise, muscles must release more energy and therefore respire faster
2) the nervous system responds by raising the heart rate, and therefore supplying muscles with the oxygen and glucose at a faster rate
3) the volume of blood pumped around the body is also increased to deliver more oxygen and glucose
4) after exercise, our heart rate may remain high as the muscles still require oxygen, a process called ‘oxygen debt’ in order to break down the lactic acid produced from anaerobic respiration
WHY does adrenaline increase our heart rate?
1) when we are in a dangerous situation, and feel anxious or scared, our heart rates also increase due to the secretion of the hormone, ADRENALINE from our adrenal glands
2) the heart rate increases, therefore supplying more blood and oxygen to our muscles, enabling more energy release for anaerobic respiration
3) this is in preparation for a ‘fight or flight’ response which allows us to fight or run away.
WHY does our heart rate decrease when we sleep?
-when we sleep our organs work slower, and require less energy
- therefore need less oxygen
WHAT’S Coronary Heart Disease?
CHD is when the coronary arteries become blocked up by a build up of fatty material (plaque).
-The fatty deposits are usually made up of CHOLESTEROL
-the build up narrows the coronary arteries which restricts blood supply to an area of cardiac muscle
-this area can then no longer receive glucose and oxygen, and cannot respire, which means it cannot contract
- this can cause problems from an angina (severe chest pains), to in severe cases, a heart attack
FACTORS that influence CHD:
-heredity
-smoking (raises blood pressure and makes blood clots more likely)
-diet (large amounts of saturated fat increases your cholesterol levels)
-high blood pressure (puts more strain onto the heart
-stress (raises your blood pressure)
-lack of exercise (exercise lowers your blood pressure and strengthens the heart)
ADAPTATIONS of arteries
ARTERIES carry blood AWAY from the heart
-has a narrow lumen : maintain high blood pressure
-thick walls : can control blood flow of the artery
-has elastic fibres: can stretch + recoil to maintain high blood pressure
ARTERIOLES branch off from arteries and are smaller ARTERIES
ADAPTATIONS of VEINS
VEINS carry deoxygenated blood back to the heart
-wide lumen: to maintain low blood pressure
-thin walls
-SEMI-LUNAR VALVES: prevent backflow of blood
VENULES are smaller VEINS
ADAPTATIONS of CAPILLARIES
-CAPILLARIES carry blood through organs and bring the blood close to every cell
-capillaries are small enough to fit between cells
-has thin ‘one-cell thick’ walls : provide short diffusion distance for materials in and out of the blood
-low pressure (wide lumen) : to allow more time for diffusion
WHY is a double circulatory system more efficient than a single circulatory system in a fish?
-the blood loses pressure when it travels through the gills
-the blood then travels slower to the other organs
HEPATIC
THE LIVER
RENAL
Kidneys
PULMONARY
Lungs
HEPATIC PORTAL VEIN
-carries blood from the digestive system to the liver
