Circulatory System Flashcards
Explain the composition of blood
Plasma - 55%
White blood cells and platelets - less than 1%
Red blood cells - 45 %
Explain red blood cells
Can also be referred to as erythrocytes or lymphocytes. They are usually shaped like bicomcave disks and are made from bone marrow. They have a protein called hemoglobin in them.
What is hemoglobin? Why is it important red blood cells have it?
Hemoglobin is a protein that contains iron. This makes it a good way to transport O2 and CO2.
Explain blood cells and platelets.
WBC are also called leukocytes and help to fight infection. A high number of WBC are a symptom of leukaemia.
Platelets are leftover fragments of bone marrow and are involved in blood clotting.
Explain plasma
It is mostly water. Plasma that escapes the vessels is absorbed by the tissues.
Explain the three different blood vessels
Arteries: high blood pressure, elastic fibres
Veins: low blood pressure, have thin wall but large inner circumference
Capillaries: smallest, wall is a single layer of epithelial cells
Go into more detail about veins
Veins have valves to keep blood moving to the heart and to prevent backflow
Explain the flow of blood through the body.
- Body tissue
- Inferior or superior vena cava
- Right atrium
- Right Av (tricuspid) valve
- Right ventricle
- Pulmonary valve/semi lunar valve
- Pulmonary artery
- Lungs
- Pulmonary veins
- Left atrium
- Bicuspid valve
- Left ventricle
- Aorta
- Tissue
What returns tissue fluid to the blood?
Lymphatic system
Why is blood considered a tissue?
Connects the system and has functions
Are erythrocytes true cells?
No, they have no nucleus or organelles.
Why don’t arteries have valves like veins?
Arteries have a higher blood pressure than veins, therefore pushing blood through them more easily.
Explain atherosclerosis and how it happens.
A disease caused by the build up of fat and plaque in an artery.
Damage to the endothelium (which is the tissue that the arteries are made of which are smooth) fat and plaque enter the walls, building up over time.
What vessels carry blood to the heart? Away?
To: veins
Away: arteries
What is the difference between the thickness of the atria and ventricles? Why?
Ventricles are thicker than atria. Blood needs more pressure to exit the heart than to enter it.
Explain the difference between the walls of the left and right ventricles
The left ventricle has thicker muscles than those of the left ventricle. This is because the left ventricle pumps blood to the entire body, therefore needing more power to do so.
Explain the heart sounds and what is happening.
lub
Here, the ventricles are contracting and the AV valves (tricuspid and bicuspid/mitral valves) are closing.
dub
Ventricles are relaxed and atria are contracting. The aortic and pulmonic (semi lunar) valves are closing.
Explain systole and diastole
Diastole: period of the cardiac cycle where the ventricles are relaxed. Blood fills the ventricles.
Systole: period of the cardiac cycle where the ventricles are contracted. Blood is ejected from the ventricles.
What is blood pressure?
The force exerted against the walls of the arteries as the heart pumps blood 120/80 is normal
What is high blood pressure?
Hypertension
Stretches the arteries beyond a healthy limit
Explain how the heart beats
- The SA node depolarizes (gets excited) and fires
- The atria contract
- SA node sends message to AV node
- AV node fires
- Ventricles contract.
Explain what an ECG is
Records electrical activity of the heart
Explain the different parts of the ECG
- P wave represents excitation of the atria as a result of the SA node firing
- QRS wave represents ventricular excitation as the result of the AV node firing
3. T wave is relaxation of the muscle
Explain vasodilation and vasoconstriction
Vasodilation is when your blood vessels open up, allowing more blood flow to your muscles. (Heat, exercise, alcohol)
Vasoconstriction is when your blood vessels shrink. (Cold)
Why is the systolic reading important?
Tells us the pressure exerted when the blood is being pumped to our body.
What’s the difference between heart attacks and strokes?
Heart attacks: blood flow to heart is blocked
Strokes: blood flow to brain is blocked
What is the function of the coronary arteries?
Provide blood to the heart muscle
Explain sickle cell anemia
Shape of blood vessels changes, causing them to get stuck and reduce circulation of blood. Can cause dizziness, joint and muscle pain, etc.
Explain coronary bypass surgery
A blocked or partially blocked artery is replaced by one from the arm, leg or chest to create a new pathway to the heart.
