Cardiovascular System Flashcards
What is the circulatory system?
Circulatory System= a network of organs and vessels responsible for the flow of blood, nutrients, gases and hormones to and from the cells in the body.
it is aka the cardiovascular system
What are the main functions of the cardiovascular system? (4 main functions)
- to transport oxygen and carbon dioxide around the body
- to distribute nutrients and transport waste
- to maintain body temperature
- to circulate hormones
What are the two types of circulatory systems?
- Open Circulatory System
2. Closed Circulatory System
What is an open circulatory system?
In an open circulatory system blood is contained in blood vessels for only part of the time. Blood bathes the internal organs directly.
Open circulatory systems are found in smaller organisms.
What is a closed circulatory system?
Closed circulatory systems are found in large complex organisms.
Blood is always found in blood vessels.
Materials are exchanged between the blood and cells.
What are the main components of the circulatory system?
Main components= heart, blood, blood vessels
What are the types of blood vessels? (3 types)
Arteries, veins, capillaries
What are arteries/what is their structure/what do they do?
Arteries= thick muscle and elastic fibres
smaller in diameter and very flexible-they stretch under pressure and recoil to move blood along.
All arteries except the pulmonary artery carry oxygenated blood away from the heart.
arteries can withstand high pressure from the heart
there are no valves in arteries
Arterioles-what are they/what do they do?
Arteries branch into arterioles
Arterioles can contract and relax
vasoconstriction= reduction in diameter of blood vessel, decreases blood flow
vasodilation= increase in diameter of blood vessel, increases blood flow
What are veins/what is their structure/what do they do?
veins= thin muscle and elastic fibres that are larger in diameter and elastic but not flexible. Valves are present.
Low pressure
All veins except the pulmonary vein carry deoxygenated blood to the heart.
venules= small vessels that carry blood back to the heart
What are the 2 major strategies that help with the flow of venous blood against gravity?
- valves in veins prevent blood from flowing backwards against the flow.
- skeletal muscles pump blood towards the heart.
What are capillaries/what is their structure/what do they do?
capillaries= the smallest type of blood vessels with extremely thin walls (walls are 1 cell thick)
little flexibility and no valves present in the capillaries.
the capillaries connect arterioles to venules
gas exchange occurs in the capillaries
Where/how does gas exchange happen in the circulatory system?
Diffusion occurs in the capillaries (this is where the exchange of gases occurs)
Particles of high concentration move to an area of low concentration.
Blood Vessels Summary Breakdown:
what are the types of blood vessels?
what are their purposes/what is their structure?
Arteries - Arterioles - Capillaries - Venules - Veins
arteries= thick-walled blood vessels that carry oxygenated blood away from the heart
veins= thin-walled blood vessels that carry deoxygenated blood towards the heart
capillaries= narrowest of all blood vessels, RBCs travel in single file
branching of capillaries increase the surface area available for diffusion. Connects the arterial and venous systems.
What causes bruises?
The capillaries have walls that are only one cell thick and are very fragile. The capillaries can get ruptured through impact.
When this happens the blood contained within them gets released into the spaces between the tissues.
This produces discolouration/swelling known as a bruise.
What is blood made up of?
Blood= plasma, red blood cells, white blood cells, platelets
Plasma- what is it/what is it made up of?
Plasma= a straw-coloured liquid that makes up 55% of blood
90% of plasma= H2O (temperature reg.)
Remaining 10% of plasma consists of:
Proteins, dissolved nutrients and wastes, dissolved gases and hormones
*the proteins transport fatty acids, vitamins, fight viral/bacterial infections, support clotting
Red Blood Cells (RBCs)- what are they/what do they do?
RBCs= aka ERYTHROCYTES
lifespan= 100-120 days
RBCs= disc-shaped/thinner in the centre (increases surface area/flexibility)
RBCs are produced in bone marrow
RBCs lose nuclei with maturity (hence their disc shape) thus they can’t replace proteins, grow or divide
RBCs contain hemoglobin