Circulatory System Flashcards
(27 cards)
What is the main organ of the circulatory system?
Heart: Pumps blood (muscle under breastbone).
The heart is a vital organ that circulates blood throughout the body.
What are the three types of blood vessels?
- Arteries
- Capillaries
- Veins
These vessels play distinct roles in transporting blood throughout the body.
What is the function of arteries?
Carry blood away from heart (usually oxygenated). Thick, muscular walls.
Arteries are designed to handle high pressure from the heart’s pumping action.
What is the role of capillaries?
Tiny vessels for gas/nutrient exchange. Connect arteries to veins.
Capillaries are where the actual exchange of oxygen, carbon dioxide, and nutrients occurs.
What is the function of veins?
Carry blood to the heart (usually deoxygenated). Have valves to prevent backflow.
Veins are essential for returning blood to the heart.
What are the components of blood?
- Red Blood Cells (RBCs)
- White Blood Cells (WBCs)
- Platelets
- Plasma
Each component has a unique function critical for the body’s health.
What is the primary function of red blood cells (RBCs)?
Carry oxygen (via hemoglobin), no nucleus.
RBCs are crucial for transporting oxygen to tissues.
What is the role of white blood cells (WBCs)?
Immune defense (fight infection).
WBCs are key players in the body’s immune response.
What do platelets do?
Help clot blood (stick to vessel tears).
Platelets are essential for preventing excessive bleeding.
What is plasma?
Fluid part; carries nutrients, wastes, hormones.
Plasma makes up the majority of blood volume and serves as a transport medium.
What is blood pressure?
Force of blood against artery walls.
Blood pressure is vital for maintaining blood flow through the circulatory system.
What is considered normal blood pressure?
~120/80 mm Hg (Systolic/Diastolic).
Maintaining normal blood pressure is crucial for cardiovascular health.
What is hypertension?
High BP that damages arteries, risks heart disease, stroke, kidney damage.
Hypertension is a serious health condition that requires management.
What is vasoconstriction?
Vessels narrow → increases BP.
Vasoconstriction is a response to various physiological needs and stress.
What is vasodilation?
Vessels widen → decreases BP.
Vasodilation helps regulate blood flow and blood pressure.
What controls the heartbeat?
Specialized cells: SA Node (Pacemaker), AV Node, Bundle of His, Bundle Branches, Purkinje Fibres.
This electrical conduction system ensures coordinated heart contractions.
What is the first sound of the heartbeat caused by?
Atrioventricular valves (Tricuspid/Bicuspid) close.
Heart sounds are important indicators of cardiac function.
What is the second sound of the heartbeat caused by?
Semilunar valves (Pulmonary/Aortic) close.
The closing of these valves marks the end of ventricular contraction.
What is the pulmonary circuit?
Right side, Right ventricle to Lungs, returns to Left atrium.
This circuit is responsible for gas exchange in the lungs.
What is the systemic circuit?
Left side, Left ventricle to Body, returns to Right atrium.
The systemic circuit delivers oxygen and nutrients to tissues.
What is the coronary circuit?
Left side, Left ventricle to Heart muscle, returns to Right atrium.
This circuit supplies blood to the heart itself.
What is hematocrit?
Percentage of blood volume made up by RBCs. Normal: ~45%.
Hematocrit levels can indicate various health conditions.
What indicates anemia?
Low RBC % → fatigue, weakness.
Anemia is a common condition that can affect overall health.
What is the oxygen exception regarding blood vessels?
Pulmonary artery: Deoxygenated blood away from heart; Pulmonary vein: Oxygenated blood toward heart.
This is unique compared to systemic circulation.
