Human Transport Flashcards
What is a double circulatory system
The heart pumps blood around the body twice per cycle (once to the lungs and once to the body)
How are red blood cells specialised for their function
Bioconcave - large SA to absorb oxygen
Haemoglobin - carries oxygen
No nucleus - more space for oxygen/haemoglobin
Flexible - to squeeze through narrow capillaries
What defence responses does the body have to prevent entry of microorganisms
The eye - chemicals in tears act as an antiseptic
The skin - acts as a physical barrier
Goblet cells - produce sticky mucus that traps pathogens
Ciliated cells - tiny hairs (cilia) waft trapped pathogens out of the airways
Blood clotting - scabs from to seal open wounds and prevent entry of pathogens
Stomach acid (HCl) - kills microbes entering stomach
How do vaccinations work
A dead or weakened from of the pathogen is injected and it stimulates the immune system.
Lymphocytes produce antibodies against the weakened pathogens antigens and when infected with the actual pathogen, memory cells remeber which antibody to produce and lymphocytes produce these faster
What do phagocytes do
Surround and engulf pathogens
Digest them with enzymes
What do lymphocytes do
Release antibodies that are complementary to antigens on the pathogen and inactivate them
Release antitoxins to neutralise toxins released by pathogens
What is the structure of an artery
Small lumen
Thick muscle wall
Maintains blood flow at high pressure
Structure of a vein
Large lumen
Thin wall
Veins to prevent backflow
Blood flows at a low pressure
Structure of a capillary
One cell thick
Short diffusion distance for exchange of materials
Why is the wall of the left ventricle thicker then the right ventricle
The left ventricle pumps oxygenated blood all around the body so a bigger push is re for the longer distance. The right ventricle pumps blood to the lungs only
What is the role of the coronary arteries
To supply the heart muscle with oxygenated blood
What is coronary heart disease
A blockage of the coronary artery with cholesterol restricts blood flow to the heart muscle, limiting oxygen delivery and resulting in anaerobic respiration and lactic acid build up
How can CHD be treated
A stent (wire mesh) is used to open up/widen a blocked artery. A balloon is inflated, stretching the wire mesh which holds the artery open and restores blood flow
What is adrenaline and where is it made
A hormone released from the adrenal glands
An effect of adrenaline in the circulatory system
Increased heart rate - more blood containing oxygen pumped to muscles for fight or flight response
