Circulatory Flashcards
Characteristic vein
Contains valves- prevent the back flow of blood
Wide lumen
Relatively thin walls with less muscle and elastic tissue
Carries at a lower pressure
Characteristics artery
No valves
Narrow lumen - maintain high blood pressure
Thick walls made of muscle and elastic tissue to prevent bursting
Carries higher blood pressure
Usually carries oxygenated blood (except pulmonary artery)
Capillaries characteristics
Made of single layers of cells
- to allow substance to passs easily from the blood into the body cell
Lumen small
- only big enough to let one red blood cell through at a time
Deoxygenated blood enters…
The right atrium
Oxygenated blood…
On the left atrium
Diastole
The strip and ventricular muscle is relaxed
The blood enters the atria through vena cava and pulmonary vein
Pressure increases in the atria
Atrial systole
The serial muscular walls contract, increasing the pressure further. —> atriovencular valves to open and the blood to flow into the ventricle
The ventricle walls are relaxed
Ventricular systole
After short delay the ventricular muscle walls contract - increasing pressure beyond of the atria
Atrioventrcicular calve close and seminar valve open
The blood is pushed out into the arteries (aorta and pulmonary arteries)
Tricuspid valve
Closes at the left side of he heart
Bicuspid valve
Closes at the left side of the heart
What si ECG
Technology used to investigate the rhythm of the heart by producing a record of electrical activity of the heart
SAN (sinoatrial node)
A specialised group of cells in the right atrium with the fastest natural intrinsic rhythm it generates a regular electrical signal and act as the heart own natural pace maker to keep the heart beating regularly
AVN atriventricular node
A group of cells stimulated by the wave of excitement from SAN and Atria it impose a delay before transmitting. The impulse to the bundle of his
- slight delay is before the AVN stimualte the bundle of his makes sure that the atria have stopped contracting before the ventricle starts
Bundle of his
A group of conducting fibers in the septum of the heart
Purkyne tissue
Conducting fibre that penetrates down through the septum of the heart spreading between and around the ventricle
This ventricle contract starts at the bottom of the ventricle so that the blood is squeezed upwards toward the main arteries
What’s happens at P
Atrial contraction
QRS
Ventricular contraction
T
Ventricular relaxation
Red blood cells features
Contain haemoglobin
Transport of oxygen
No nucleus
—> more space for haemoglobin
Biconcave disk
—> large SA:V ratio
White blood cell
Lymphocytes : production of antibodies
Phagocytes : involved in phagocytosis
Platelets function
Involved in blood clotting
- prevent entry of pathogens
- minimise blood loss
Injury process
1) platelets stick to the sit to damage
2) chemical signal are released from the platelet to attract nearby cells and clump them together
3) thromboplastin catalyse the conversion of inactive prothrombin to active thrombin
4) thrombin then catalyse the conversion of solute fibrinogen to insoluble fibrinogen
5) thrombin then catalyse the conversion of soluble fibrinogen to insoluble fibrinogen
6) forming a mesh which traps RBCs and creates a scab
