2.2 Structure and function of the cardiovascular system Flashcards
What three elements make up the cardiovascular system?
Heart, blood, blood vessels
State the composition of blood
Plasma - 55%
White blood cells (leukocytes and platelets) - <1%
Red blood cells (erythrocytes) - 45%
What is the function of erythrocytes?
Carry & transport oxygen and carbon dioxide
Contains an iron-rich protein called haemoglobin
Oxygen binds to haemoglobin to be transported around the body as oxyhaemoglobin
What is the function of leukocytes?
Protection from infectious diseases and foreign substances
One part of the body’s immune system
What is the function of platelets?
Blood clotting and repair damage to cells
Stops the spread of pathogens
Another part of the body’s immune system
BE ABLE TO LABEL
THE HEART - ALL OF THE BITS
What are the two intrinsic regulators?
Sinoatrial node (SA node)
Atrioventricular node (AV node)
(heart has a pacemaker of it’s own creating electrical impulses in the muscular walls)
Summarise the regulator process
SA node generates nerve impulses that travel throughout the heart wall. This causes both atria to contract.
SA node impulses meet AV node there’s a delay of about 0.1 seconds.
This delay allows atria to empty into ventricles, before ventricles contract.
AV node generates nerve impulses that travel through the septum which cause the ventricles to contract.
What are the three extrinsic regulators?
Sympathetic, parasympathetic, adrenaline (overrides the intrinsic regulation of the heart)
What are sympathetic regulators?
Connected to the heart via the sympathetic cardiac nerve
Responsible for increasing heart rate
Increases the force of cardiac muscle contractions
What are parasympathetic regulators?
Slows down your heart rate
Connected to the heart via the vagus nerve
Responsible for slowing the heart rate
Vagus nerve decreases the force of cardiac muscle contractions
What are adrenaline regulators?
Released from the adrenal glands which increase the heart rate and the force of contraction.
Also increases breakdown of glycogen and lipids and redistribution of blood to the skeletal muscles.
BE ABLE TO LABEL AND DRAW
of blood going around the body from the lungs to the heart to the body, oxygenated blood and deoxygenated blood
What is the first step in circulation? P or S
Deoxygenated blood enters the right atrium through the superior and inferior vena cava S
What is the second step in circulation?
Deoxygenated blood travels through tricuspid valve and into the right ventricle S
What is the third step in circulation?
Deoxygenated blood leaves the heart through the pulmonary artery and returns to the lungs P
What is the fourth step in circulation?
Gaseous exchange takes place. CO2 deposited. O2 taken into the bloodstream P
What is the fifth step in circulation?
Oxygenated blood leaves the lungs and goes back to the heart through the pulmonary vein P
What is the sixth step in circulation?
Enters the left atrium P
What is the seventh step in circulation?
Travels through the bicuspid valve to the left ventricle S
What is the eighth step in circulation?
Oxygenated blood leaves the heart through the aorta S
What is the ninth step in circulation?
Oxygenated blood travels to the systems in the body such as liver, kidneys S