Human transport Flashcards
Composition of blood
Red blood cells
White blood cells
Platelets
Plasma
Role of plasma
Transport of:
CO2
Digested food and mineral ions
Urea
Hormones
Heat energy
Role and adaptation of red blood cells
Carrying oxygen to respiring cells:
Full of haemoglobin (to bind to oxygen)
No nucleus (more space for haemoglobin)
Biconcave disc shape (large SA:V ratio)
Phagocytes role/function
Phagocytosis - ingesting pathogens
Sensitive cell membrane detects chemicals produced by pathogenic cells
On encounter, they engulf the cell and release digestive enzymes to destroy it
(non specific)
Lymphocytes role/function
Produce antibodies - proteins with a complementary shape to antigens on the pathogen
Antibodies produced only fit one type of antigen on a pathogen
Antibodies destroy pathogens (by restricting their movement)
Immune response to infection
Pathogen enters blood stream and multiplies
Phagocytes encounter pathogens and engulf and digest
Eventually the pathogen encounters a lymphocyte which recognises its antigens
Lymphocyte produces specific antibodies for the particular pathogen, and clones itself to produce more
Antibodies destroy pathogens, and phagocytes engulf and digest the destroyed pathogens
Methods of creating a safe vaccine
Harmless versions of pathogen:
Killing it
Making it unable to grow or divide
Using fragments of pathogens
Function of vaccines
Lymphocytes recognise antigens and produce specific antibodies
After recovery memory cells are produced and remain in blood stream
Future infection will trigger a much faster and larger response preventing disease
Platelets and blood clotting
Platelets are fragments of cells:
When the skin is broken, platelets arrive to stop the bleeding
Platelets convert soluble fibrinogen proteins into insoluble fibrin, forming a mesh on the wound
Red blood cells are trapped, forming a clot
The clot dries and develops into a scab
This prevents blood loss and bacteria entering
Structure of heart
Left of diagram (deoxygenated blood):
Vena cava -> Right atrium -> Tricuspid valve -> Right ventricle -> Semi-lunar valve -> Pulmonary Artery
Right of diagram (oxygenated blood):
Pulmonary vein -> Left atrium -> Bicuspid valve -> Left ventricle -> Semi-lunar valve -> Aorta (and body)
Why is the left side of heart thicker
Why is there low pressure blood on right
1: Thicker muscle walls so a high enough pressure is produced for blood to travel around body
2: Prevent damage to capillaries in lungs
Natural resting heart rate controlled by
Pacemaker - sends out electrical impulses to coordinate contraction of cardiac muscle
Exercise and heart rate
Heart pumps blood to respiring cells to supply O2 and glucose, and remove respiratory waste
Muscle cells respire faster during exercise
Increased respiration -> more O2 + glucose supply and waste removal
= Heart rate increases + volume of blood pumped
Adrenaline also increases heart rate
Coronary Heart Disease
Plaque (fatty material) builds up in coronary arteries
Partial/complete blockage reduces blood flow, resulting in lack of oxygen for heart muscle
Partial -> heart pains, Complete -> heart attack
Risk factors of CHD
Obesity: Extra weight strains heart, can lead to Type 2 diabetes which further damages blood vessels
High BP: Increased force of blood against artery walls, leads to damage of vessels
High cholesterol: Speeds up plaque buildup
Smoking: Chemicals cause increase in plaque buildup and BP, and CO reduces oxygen capacity of RBCells
