Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
|
Need for transport systems in animals |
High metabolic rate - active
Large surface area:volume ratio Multicellular - large diffusion distance Movement of other substances in blood e.g. hormones |
|
|
Double and single circulatory system |
Single pass through the heart once for one circuit of the body
Double pass through the heart twice for one circuit around the body Fish single, mammals double |
|
|
Double and single circulatory system diagram
|
|
|
|
Advantages of a double circulatory system |
Flow around the body can be at a high pressure then the lungs - more quickly
Mammals need to maintain body temperature so lots of energy Low pressure in single |
|
|
Open and closed circulatory system |
Closed - blood enclosed in blood vessels and not in direct contact with cells - leave and enter by diffusion
Open - not enclosed in blood vessels all the time e.g. in insects Insect blood called haemolymph - no carbon dioxide or oxygen only nutrients and food Muscular pumping organ like a heart - long tube and pumps up towards the head where it pours out The disadvantage as pressure is low and slow and circulation may be affected by body movements |
|
|
Insect circulatory system diagram |
|
|
|
Components of blood vessels |
Elastic fibres - elastin to stretch and recoil - vessel walls with flexibility
Smooth muscle - contracts or relaxes to change the size of the lumen Collagen - structural support to maintain the shape |
|
|
Arteries and arterioles |
Carry blood away from the heart - oxygenated
Under high pressure - withstand force Inside to outside - endothelium, elastic fibres, smooth muscle, collagen fibres Walls thick and muscular so stretch and recoil with heartbeats and maintain high pressure Inner lining folded so it can expand to maintain pressure Arterioles are small blood vessels from artery to capillary Layer of smooth muscle to constrict to reduce rate of flow or divert to other regions |
|
|
Capillaries |
From arterioles to venules
Lumen so small - same as 1 red blood cell so short diffusion distance Walls single layer of squamous endothelium to reduce diffusion distance Leaky walls so blood plasma and dissolved substances leave Provide large surface area |
|
|
Venules and veins |
Venules from capillaries and join together to form veins
Venules have thin layers of muscle and elastic tissue and collagen Veins carry blood back to the heart - deoxygenated Inside to outside - endothelium, elastic layer, muscle layer, collagen Under low pressure Don’t have a pulse and have a large lumen Lots of collagen and little elastic fibres as no stretch and recoil and not used to reduce blood flow Smooth, thin endothelium lining so easy blood flow Valves to prevent backflow - open when blood in one direction but close when moving in another Muscles contract to force blood back to the heart |
|
|
Vein and artery diagram |
|
|
|
Tissue fluid |
Surrounds cells in tissues
Dissolved substances in the plasma leave the capillaries Red blood cells and large proteins too big to get through Cells take in oxygen and nutrients from it and release waste At the start of the capillary hydrostatic pressure in the capillaries is greater than tissue fluid so forces fluid out Oncotic pressure generated by the plasma proteins and stays the same The arterial end of a capillary has a high hydrostatic pressure so pushed the fluid into the tissues Hydrostatic pressure then drops but oncotic pressure remains the same so some fluid including the waste and water move back into the capillary at the venule end |
|
|
Lymph system |
Some of the tissue fluid doesn’t return to the capillaries
Now called lymph and return to blood by lymphatic system Lymph capillaries smallest Valves to prevent backflow Moves towards main lymph vessels in thorax and returned near heart Contains lymphocytes made at lymph nodes - immune system |
|
|
Blood, tissue fluid or lymph components - red blood cells |
Blood - yes Tissue fluid - no Lymph - no Too large to leave blood vessels |
|
|
Blood, tissue fluid or lymph components - white blood cells |
Blood - yes Tissue fluid - no Lymph - yes Most in lymph |
|
|
Blood, tissue fluid or lymph components - platelets |
Blood - yes Tissue fluid - no Lymph - no Only escape when capillaries damaged |
|
|
Blood, tissue fluid or lymph components - proteins
|
Blood - yes Tissue fluid - no Lymph - yes - antibodies Too large to leave capillaries |
|
|
Blood, tissue fluid or lymph components - water |
Blood - yes Tissue fluid - yes Lymph - yes High water potential in lymph and fluid |
|
|
Blood, tissue fluid or lymph components - dissolved solutes |
Blood - yes Tissue fluid - yes Lymph - yes Can move freely |
|
|
The heart valves |
Atrioventricular and semi-lunar valves Prevent back flow of blood
Open and close due to pressure Pressure behind open Pressure in front close Lub-dub sound - lub atrioventricular valve closing and dub sound from semi-lunar valve closing |
|
|
Heart structure diagram |
|
|
|
Heart flow chart |
Vena cava Right atrium Atrioventricular valve Right ventricle Semi-lunar valve Pulmonary artery Lungs Pulmonary vein Left atrium Atrioventricular valve Left ventricle Semi-lunar valve Aorta |
|
|
Cardiac cycle - diastole |
The heart relaxes - both atria and ventricles
Semilunar valve closes as high pressure in pulmonary artery and aorta Atria fill with blood increasing their pressure Pressure in ventricles falls so the atrioventricular valves open and blood flows passively |
|
|
Cardiac cycle - atrial systole |
Atria contract, ventricles relax
Atria decrease volume and increase pressure so pushes blood into ventricles through atrioventricular valve Slight increase in ventricles pressure and volume as receive blood |
|
|
Cardiac cycle - ventricle systole |
Ventricles contract, atria relax
Ventricles decrease in volume and increase pressure Force atrioventricular valve shut and open semilunar Blood forced out of pulmonary artery/aorta then back to diastole |
|
|
Heart tissues for pressure |
Atria - thin walls because little pressure and only going to ventricles
Right ventricle - walls thicker than atria but still thin as only going to lungs so low pressure Left ventricle - thicker than the right as under high pressure to go all the way around the body |
|
|
Coordination of the cardiac cycle |
Myogenic - initiates its own coordinations and rhythm
Sino-atrial node (SAN) generates electrical activity in the wall of the right atrium and causes the atria to contract Non-conducting layer of tissue prevents the ventricles contracting SAN activity is picked up by the atrioventricular node (AVN) Slight delay to allow the ventricle to fill then travels down the bundle of His of Purkyne fibres Ventricles contract from bottom up to push blood up |
|
|
Electrocardiograms |
ECGs measure the electrical activity of the heart P = atria contract QRS = Ventricles contract T = ventricles relax |
|
|
Heart problems |
Bradycardia - slow heart rate
Tachycardia - fast heart rate Fibrillation - irregular heartbeat - atria and ventricles out of time Eutrophic heartbeat - an extra heartbeat - feels as through a heartbeat has been missed |
|
|
Transporting oxygen |
Erythrocytes adapted to transport oxygen
Biconcave shape for large SA No nuclei to carry haemoglobin Haemoglobin carries the oxygen - globular protein with iron haem group Each haemoglobin can bind to 4 oxygen molecules Oxygen has a high affinity for oxygen Forms oxyhaemoglobin |
|
|
Partial pressure of oxygen |
Partial pressure of oxygen (pO2) measures the oxygen concentration
Higher concentration = higher pO2 Oxygen loads onto haemoglobin when there’s a high pO2 Oxygen unloads when low pO2 High pO2 in lungs so load on Low pO2 in respiring cells so load off |
|
|
Oxygen dissociation curve |
|
|
|
Oxygen dissociation curve explanation |
High affinity for oxygen at a high pO2 Low affinity for oxygen at low pO2 Hard for the first molecule of oxygen to attach then changes shape for the next two to get in easier Then hard for last oxygen to attach so few at 100% saturation |
|
|
Fetal haemoglobin |
A fetus gets oxygen supply from its mother’s blood in the placenta
Fetal haemoglobin has a higher affinity for oxygen than adult haemoglobin If the fetal haemoglobin had the same affinity for oxygen little oxygen would be transferred as the oxygen saturation of the mother’s blood has decreased as it moves around the body |
|
|
Fetal haemoglobin curve |
|
|
|
CO2 transport |
Haemoglobin gives up its oxygen more easily at high pCO2 so at respiring cells
CO2 reacts with water to form carbonic acid - catalysed by carbonic anhydrase enzyme Carbonic acid dissociates into H+ and HCO3- ions The H+ ions cause oxyhaemoglobin to unload its oxygen to take up the H+ ions to form haemoglobinic acid HCO3- ions diffuse out of the red blood cell and the chloride shift of Cl- ions prevent pH change When blood reaches the lungs there is a low pCO2 so H+ and HCO3- ions recombine to form carbon dioxide 10% combine directly with haemoglobin to form carbaminohaemoglobin and 5% dissolved in blood plasma |
|
|
Bohr effect |
Higher affinity for oxygen at a low pCO2 as less carbon dioxide will travel in the haemoglobin
|
