Cardiovascular system Flashcards
What does the cardiovascular system transport?
Nutrients
Oxygen
CO2
Hormones
What does the cardiovascular system consist of?
Heart and blood vessels
Where does blood enter the heart?
Through the atria and passes through ventricles
What do the heart valves prevent?
Backflow
Why does the left ventricle have a thicker and stronger muscular wall?
It has to pump blood around the whole body
what does the bicuspid and tricuspid valves prevent blood doing?
Prevents flowing backwards from ventricles into atrium
Role of the arteries
Carries blood away from the heart
Aorta divides into smaller arteries called arterioles.
State the features of arteries
Thick layer of muscle and elastic tissue
Features of capillaries
One cell thick
Veins
Blood is at a lower pressure so the lumen of the vein is larger than an artery
Components of blood
Plasma
Platelets
Red blood cells
White blood cells
Role of plasma
Contains hormones
Role of platelets (thrombocytes)
Plays important role in blood clotting
Role of red blood cells
Filled with haemoglobin - protein that transports oxygen from lungs to the tissue
Role of white blood cells
Protection against infection.
What is atrial fibrillation?
Fast and irregular heart beat
What is ventricular fibrillation?
Disorganised electrical signals in ventricles/irregular heartbeat that affects ventricles
Tachycardia
Rapid heartbeat 100+ BPM
Bradycardia
Slow heartbeat less than 60 BPM
Ectopic heartbeat
Changes in the heartbeat
Why is the human circulatory system known as a double circulatory system?
Blood passes through the heart twice for every circuit of the whole body.
What happens in the first loop of the double circulatory system?
From the heart to the lungs and then back to the heart.
What happens in the second loop of the double circulatory system?
From the heart and through all the other organs and then back to the heart.
What is the cardiac cycle?
On-going sequence of contraction and relaxation of the atria and ventricles that keeps blood going around the body.
Give the first step of the cardiac cycle
Ventricles both relax and the atria contract which decreases their volume causing atrioventricular valves to open and forces blood through the valves into the ventricles.
Give the second step of the cardiac cycle
Ventricles contract and atria relax.
Atria relax and the ventricles contract. The pressure is higher in the ventricles than the atria so it shuts off the atrioventricular valves to prevent backflow.
Give the third step of the cardiac cycle
Ventricles and atria relax.
Increases volume and lowers pressure in the heart chambers. Higher pressure in the PA and aorta closes the semilunar valves to prevent back flow.
Explain the PQRST pattern
P - depolarization of the atria that is initiated by electrical signs generated by the SAN
QRS: Depolarization of ventricles initiated by electrical signs generated by AVN
T: Repolarization of ventricles.
Pressure changes in the heart and blood vessels.
Blood enters from the right atrium from the vena cava.
Flows via the bicuspid valve through the right ventricle
From the right ventricle, pumped into the pulmonary artery to the lungs.
Returning from lungs via pulmonary vein and the blood enters the left atrium.
Flows into left ventricle
From left ventricle, blood is pumped into aorta around the body.
What is CHD?
Heart disease that is caused by narrowing or blocking of coronary arteries caused by a build up of atherosclerosis.
What can form within the narrowed arteries?
Blood clots
What happens if a blood clot blocks the coronary arteries?
The heart becomes starved of glucose and oxygen and starts to die which can cause myocardial infarction.
Give some risk factors of CHD
Hypertension - thickens the walls of the arteries and reduces diameter of lumen causing increased blood pressure
Smoking
Alcohol consumption
High cholesterol
Diabetes
Age and sex
Genetic factors
Ethnicity
What is the impact of CHD on systems within the body?
Symptoms will vary on depending the severity of and location of the narrowing arteries.
- Chest pain
- SOB
- Feeling faint
- Feeling sick
What can happen if CHD is untreated or undetected?
It can lead to MI when a segment of the heart becomes starved of oxygen.
Give some common treatments for CHD
Blood thinners: prevents formation of blood clots
Statins: lowers cholestrol
Betablockers: blocks effects of adrenaline
Lifestyle changes
Angioplasty: inserting a balloon in to widen arteries
CAB: uses a patients blood vessels
Heart transplant: used in cases that may cause heart failure.
