Cardiovascular System Flashcards
What is the function of the cardiovascular system?
To pump blood around the body so oxygen can be delivered
What are the chambers of the heart called?
-Right atria
-Left atria
-Right ventricle
-Left ventricle
What are valves?
Consists of leaflets or cusps that allow movement of blood in only one direction
What are the names of the heart valves?
Atrioventricular valves =
-Tricuspid valve
-Mitral (bicuspid) valve
Semilunar valves =
-Pulmonary valve
-Aortic valve
What is oxygenated blood?
Blood that is rich in oxygen
What is deoxygenated blood?
Blood that is not rich in oxygen / lacks oxygen
Which process is oxygen used for in the body?
Oxygen is used for cellular respiration
What type of product is carbon dioxide in cellular respiration?
A bi product which the heart must pump back to the lungs to be exhaled
What products does blood carry?
-Oxygen
-Carbon dioxide
-Waste products
-Electrolytes
-Fatty acids
-Insulin
-White blood cells
-Antibodies
Right atria
Receives deoxygenated blood from the body and then empties the blood into the right ventricle
Left atria
Receives oxygenated blood from the lungs and then empties the blood into the left ventricle
Right ventricle
Pumps deoxygenated blood to the lungs
Left ventricle
Pumps oxygenated blood to the body
Aortic valve
Located between the left ventricle and the aorta
Pulmonary valve
Located between the right ventricle and the pulmonary artery
Mitral (bicuspid) valve
Located between the left atrium and left ventricle
Tricuspid valve
Located between the right atrium and right ventricle
What are the different layers of the heart called?
-Pericardium (outer layer)
-Myocardium (middle layer)
-Endocardium (inner layer)
Why is the pericardium important?
Without the pericardium the heart will dry up and touch parts it shouldn’t
Pericardium
-It is a fibrous sac that encloses the heart and the blood vessels
-It protects and lubricates the heart to keep it in place within the chest
Myocardium
-It is the muscular layer of the heart wall
-It facilitates contraction and relaxation of the heart wall to allow the heart to pump blood into the systemic circulation
Endocardium
-It is a thin smooth membrane which lines the inner surfaces of the heart chambers and valves
-It provides smooth surfaces for the interior chambers of the heart so blood can easily flow across them
Where is the heart located?
It is located in the middle mediastinum
Anatomy of the heart
-The right atrium receives blood from the veins that has already circulated through the body and pumps it over to the right ventricle through a valved opening called the tricuspid valve
-From the right ventricle blood travels through another valve called the pulmonary valve into the pulmonary artery which carries deoxygenated blood to the right and left lungs where carbon dioxide is exhaled and oxygen is picked up
-The oxygenated blood returns to the heart via one of the four pulmonary veins which bring it to the left atrium
-From the left atrium blood travels through the mitral valve into the left ventricle
-From the left ventricle blood travels through the aortic valve into the aorta which pumps blood to the rest of the body
What are the two important circulation processes?
-Sytemic circulation
-Pulmonary circulation
What is the size of the heart?
It is about the size of your clenched fist
Which blood vessel carries oxygenated blood?
Arteries except the pulmonary artery
Which blood vessel carries deoxygenated blood?
Veins except pulmonary vein
What is the difference between arteries and veins?
Arteries:
-Have high pressure
-Thick walls
-Narrow lumen
-Large amounts of elastic fibres and smooth muscle
-Do not have valves
-Largest artery in the body is the aorta
Veins:
-Have low pressure
-Thin walls
-Thick lumen
-Small amounts of elastic fibres and smooth muscle
-Have valves
-Largest vein in the body is the vena cava
What is the difference between the superior vena cava and the inferior vena cava?
Superior vena cava:
-Receives blood from the upper parts of the body such as the neck, head, chest and arms
Inferior vena cava:
-Receives blood from the lower parts of the body such as the legs and feet
What are the three layers of the pericardium?
-Fibrous
-Parietal
-Visceral
Fibrous pericardium
-Very dense
-Has non flexible connective tissue
-Helps protect and anchor the heart
Pericarditis
An infection of the pericardium
Which blood vessels carry blood away from the heart and what chambers do they exit from?
-Pulmonary artery exits from the right ventricle
-Aorta exits from the left ventricle
Which blood vessels carry blood towards the heart and what chambers do they empty to?
-Superior vena cava, inferior vena cava and the coronary sinus empty into the right atrium
-The four pulmonary veins empty into the left atrium
How are electrical signals conducted to the ventricles?
-Electrical impulses travel from the sinoatrial node (SAN) to the atrioventricular node (AVN)
-Impulses are slowed down for a short period of time before continuing down the conduction pathway via the bundle of His into the ventricles
Atrioventricular node
-Located at the junction between the atria and the ventricles
-It is an electrical gateway keeper for both the atria and the ventricles and allows efficient ventricular filling by introducing a delay
Sinoatrial node
-Located in the right atrium
-It is known as the pacemaker of the heart as it continuously generates electrical signals which set the heart in a normal rhythm and rate
Bundle of His
-Located in the interventricular septum
-It is a collection of cells that carry electrical signals from the AV node to the bundle branches
Septum
Separates the heart from the mixing of oxygenated and deoxygenated blood
Bradycardia
-Heart rate below 60 beats per minute (bpm)
-This can be caused if there’s any issues with the SA node
Tachycardia
-Heart rate above 100 beats per minute (bpm)
-This can be caused by doing intense exercise or as a response to stress
Purkinjie fibres
-Located just beneath the endocardium
-These fibres allow the heart to contract normally in a synchronised way
What is the resting heart rate?
60 to 90 beats per minute (bpm)
Pulse pressure
The difference between the systolic pressure and the diastolic pressure
Systolic pressure
The amount of pressure experienced by the arteries while the heart is beating
Diastolic pressure
The amount of pressure experienced by the arteries while the heart is resting in between heart beats
Blood pressure
Blood pressure is measured by using a sphygmomanometer which gives readings of systolic and diastolic pressure in mm Hg
Hypertension
It is high blood pressure which can occur because of:
-Eating too much salt
-Not eating a healthy balanced diet
-Smoking
-Alcohol
-Stress
-Lack of exercise
-Other health conditions
Hypotension
It is low blood pressure which can occur because of:
-Dehydration
-Pregnancy
-Resting for too long
-Not eating much salt
-Other health conditions
What is the difference between the right side of the heart wall and the left side of the heart wall?
Left side of the heart wall:
-Thicker and muscular than the right side
-Pumps blood to the rest of the body which is a large distance
-Long distance = high pressure
Right side of the heart wall:
-Only pumps blood to the lungs which is a short distance
-Short distance = low pressure
ECG
ECG stands for electrocardiography which records the rhythm, heart rate and electrical activity of the heart
ECG waves
-P wave = atrial depolarisation
-QRS complex = ventricular depolarisation
-T wave = ventricular repolarisation
Atrial depolarisation
The atria contracts which increases the pressure forcing the atrioventricular valves to open to allow the atria to start filling the ventricles
Ventricular depolarisation
-The ventricles contract increasing the pressure which forces the atrioventricular valves to close
-When the pressure from the ventricles is higher than the pulmonary artery and the aorta the semilunar valves are forced to open which allows blood to be pumped into the major arteries
Ventricular repolarisation
-This is when the ventricles relax before filling again to alllow the ventricles to enter the state of depolarisation
-The blood vessels return blood to the heart in preparation for the next ventricular contraction
How is blood viscosity determined by?
By the ratio of red blood cells to plasma volume
Calculation of mean arterial pressure (MAP)
Diastolic + (0.33 x (systolic - diastolic))
What happens when blood pressure changes?
-The heart ability to control the pressure is limited which means it can send signals which travel to the brain
-The medulla oblongata picks up these receptors as it is the part of the brain that is connected to the spinal cord
-The medulla oblongata controls the breathing rate, heart rate and blood pressure
-This allows homeostasis to occur, which is bringing back normal conditions through certain mechanisms
What happens if the brain cannot respond to the heart when it recieves receptors?
Homeostasis cannot be achieved which means blood pressure will not be controlled
Sympathetic nervous system
When activated, the body triggers a response called the fight or flight response which increases the heart rate and blood pressure
Parasympathetic nervous system
When activated, the body enteres a state of relaxation which slows the heart rate, lowers blood pressure and promotes digestion
Adrenaline (epinephrine)
Adrenaline is released from the adrenal glands during the body’s fight or flight response which makes the heart beat faster and increases blood flow to the brain and muscles
What medications stop the production of adrenaline?
Beta blockers stop adrenaline from binding to receptors to control blood pressure and heart rate
What is negative feedback?
This type of feedback occurs to balance conditions which achieve homeostasis
What can the brain do when blood pressure is low?
The brain can increase the sympathetic nerves which increase force of contractions
Vasodilation
Widening of blood vessels
Vasoconstriction
Narrowing of blood vessels
How can the kidneys lower blood pressure?
They can regulate water by getting rid off water and toxins which lowers the blood volume decreasing blood pressure
What determines blood volume?
Fluid intake and fluid loss
What determines the cardiac output?
Cardiac output = stroke volume x heart rate
What is the outermost layer of the heart’s serous pericardium?
Parietal pericardium
Chordae tendineae
-Are fibrous connections between the valve leaflets and the papillary muscles
-Are structures that prevent the prolapse of the atrioventricular valves
What is the difference between the systemic circulation and the pulmonary circulation?
Systemic circulation:
-Systemic circulation moves blood between the heart and the rest of the body
-Brings oxygenated from the heart to the rest of the body
Pulmonary circulation:
-Pulmonary circulation moves blood between the heart and the lungs
-Brings deoxygenated blood back to the heart
Where does the exchange of oxygen occur?
In the capillaries
