Heart Flashcards
The natural resting heart rate is controlled by a group of cells
located in where
the right atrium that act as a pacemaker
The coronary arteries provide the main blood supply to the hear
Where are coronary arteries and what do they do
The coronary arteries provide the main blood supply to the heart
branch outside aorta
What are arteries and what are there adaptations
arteries must be able to withstand high pressures generated by the contracting heart, and maintain these pressures when the heart is relaxed
The wall of the artery is relatively thick smooth muscle and elastic fibres
The elastic fibres allow the artery wall to expand around blood surging through at high pressure when the heart contracts, these fibres then recoil when the heart relaxes –
this alongside a narrow lumen maintains high blood pressure
Veins
veins receive blood that has passed through capillary networks; blood is at very low pressure and must be returned to the heart
The wall of the vein is relatively thin with thinner layers of collagen, smooth muscle and elastic fibres
The lumen of the vein is much larger than that of an artery(ensures blood is transported efficiently maintains pressure
Veins contain valves that prevent the backflow of blood, helping return blood to the heart
Capillaries
Arteries branch into capillaries
capillaries carry blood close to every cell to exchange substances
permeable walls substances can diffuse
supply food and oxygen take away co2
Walls one cell thick increases diffusion as distance shorter
What is the double circulatory system
he right ventricle pumps blood to the
lungs where gas exchange takes place.
The left ventricle pumps
blood around the rest of the bod
as there is no mixing of oxygenated and deoxygenated blood. This means that blood leaving the heart to travel to the body is rich in oxygen.
Red blood cells
Carry oxygen from lungs to all cells in body
shape biconcave disc gives large surface area to absorb oxygen
contains red pigment haemoglobin which binds to oxygen to become oxyhaemoglobin
in body tissues reverse happens it splits up into oxygen and haemoglobin
Plasma
Carries everything(Plasma is a watery fluid in which holds all the components of blood flow. )
blood cells
glucose and amino acid soluble products of digestion absorbed from gut taken to cells of the body
c02
hormones
urea(liver to kidneys
proteins
antibodies and antitoxins
pathway
body- vena cava - right atrium - right ventricle - pulmonary artery - lungs - pulmonary vein - left atrium - left ventricle - aorta
What are platelets and function
Platelets are fragments of cells that are used to clot the blood. Without platelets, there would be excessive bleeding every time you cut yourself and had a wound.
also helps It also prevents pathogens from entering your wound.
