Blood
This component of blood transports oxygen from the lungs to the body tissues.
Red blood cells.
These blood vessels have thick muscular walls to withstand high pressure.
These are the two upper chambers in the heart.
Atria
This term describes contraction of the heart muscle
Systole
This disease is caused by a lack of clotting factors, leading to excessive bleeding.
Hemophilia.
There are more of these cells during an infection.
White blood cells.
These structures prevent back flow of blood in veins
One-way valves.
This large artery carries oxygenated blood from the left ventricle to the body.
Aorta
This is the internal pace maker of the heart.
Sinoatrial node
This condition occurs when a clot blocks the blood flow to the brain.
Ischemic stroke
These long threads form a network that trap red blood cells in a clot.
Fibrin
These structures open or close to control blood flow in capillary beds.
Precapillary sphincters
This chamber has the thickest myocardium in the heart.
Left ventricle.
Which valves open when the ventricles contract?
The aortic and pulmonary semilunar valves.
Anemia - caused by low red blood cell numbers or low hemoglobin
Sickle cell anemia - genetic condition that produces abnormally shaped red blood cells.
These cells produce every type of blood cell in the body.
Why are capillary walls only one cell thick?
To allow for efficient diffusion of gases, nutrients, and wastes between blood and tissues.
A red blood cell has just left the lungs carrying oxygen. List the six next structures (including valves) it will pass through in the heart before reaching the body.
Pulmonary veins --> left atrium --> left atrioventricular (bicuspid) valve --> left ventricle --> aortic semilunar valve --> aorta
These small fibres are the last structures the electrical signal reaches before the ventricles contract.
Purkinje fibres
What is the role of thrombin in blood clotting?
Converting fibrinogen into fibrin.
How do vasoconstriction and vasodilation regulate blood flow?
Muscles in arteries constrict to reduce vessel diameter (in vasoconstriction) or relax to increase vessel diameter (in vasodilation) to control blood flow and blood pressure.
What is the septum and what function does it serve?
A muscular wall that separates the left and right sides of the heart to prevent mixing of oxygenated and deoxygenated blood.
Explain why atrioventricular valves close during ventricular systole.
Pressure in the ventricles becomes higher than in the atria, forcing the AV valves to close. This prevents backflow into the atria.
How does vasoconstriction of arteries affect blood pressure, and why?
Vasoconstriction increases blood pressure by narrowing the vessel diameter, which increases the resistance to blood flow. This requires higher pressure to move blood through the vessels.