Cardiovascular System
Structure
The Cardiovascular system has 3 main elements
1. The heart (Cardiac muscle)
2. Blood
3. Blood Vessels (Arteries, veins and capillaries)
Types of blood vessels
Arteries
Carries oxygenated blood away from the heart.
The blood is under high pressure.
Thick muscular walls.
veins
Carries deoxygenated blood back to the heart.
Blood under lower pressure.
Thinner walls than arteries.
capillaries
Tiny, thin walled structures.
Allow for diffusion of gas.
Functions of the cardiovascular system
THERMO REGULATION
In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation. This allows more heat to be lost from the blood.
In the cold, blood vessels at the skin’s surface close. This process is called vasoconstriction and takes blood away from the surface of the skin to help prevent it from losing heat.
TRANSPORTATION OF NUTRIENTS
The blood carries nutrients such as glucose and amino acids around the body. These are diffused via the capillaries.
TRANSPORTATION OF OXYGEN
Red blood cells transport oxygen to the working muscles. Without this our muscles would not be able to function.
REMOVAL OF WASTE PRODUCTS
Waste products such as carbon dioxide and lactic acid are transported out of the body in the blood.
the pulmonary and systemic circuits
- The pulmonary circuit takes deoxygenated blood from the the heart to the lungs.
- Blood is oxygenated in the lungs and transported back to the heart.
- The blood is pumped from the heart to the body via the systemic circuit.
- Here the oxygen in the blood is used by the working muscles and transported back to the heart.
- The process then begins again.
key terms
HEART RATE
The number of times the heart beats in a minute.
STROKE VOLUME
The amount of blood ejected per beat of the heart.
blood pressure
The strength exerted by the blood on the vessel walls as a result of the heart beating.
cardiac output
The amount of blood ejected from the heart per minute.