Blood & The Cardiovascular System Flashcards
Q: What are the three main functions of blood?
A:
- Transportation
- Regulation
- Protection
Q: What are the main transportation functions of blood?
A:
Carries oxygen from lungs to cells
Moves carbon dioxide from cells to lungs
Delivers nutrients from digestive system
Distributes hormones
Transports heat and waste products
Q: What are the regulatory functions of blood?
A:
Maintains body fluid balance
Controls pH through buffers
Regulates body temperature
Manages cellular water content
Controls osmotic pressure
Q: What are the protective functions of blood?
A:
Forms clots to prevent blood loss
White blood cells fight infection
Contains protective proteins (antibodies, interferons, complement)
Q: What are buffers in blood?
A: Chemicals that convert strong acids or bases into weak ones to help control pH
Q: How does blood protect against infection?
A: Through white blood cells performing phagocytosis and protective proteins like antibodies and interferons
Q: What does blood transport from the digestive system?
Nutrients
Q: What are the two main components of whole blood?
A:
1. Blood Plasma (55%)
2. Formed Elements (45%)
Q: What are the formed elements in blood?
A:
Red Blood Cells (RBCs): >99% of formed elements
White Blood Cells (WBCs): <1%
Platelets: <1%
Q: What is the buffy coat in centrifuged blood?
A: A thin layer between plasma and RBCs made up of WBCs and platelets.
Q: What fluid surrounds body cells and is constantly renewed by blood?
A: Interstitial fluid.
Q: What is blood plasma?
A: The liquid part of blood, mostly water with dissolved nutrients, hormones, and waste products.
Q: What are the functions of blood related to oxygen and nutrients?
A:
Blood carries oxygen from the lungs and nutrients from the digestive system to body cells.
Q: How does blood help with waste removal?
A: Blood moves carbon dioxide and waste from cells to interstitial fluid, then transports the waste to organs like the lungs, kidneys, and skin for elimination.
Q: Why is blood considered a connective tissue?
A: It has cells suspended in a liquid extracellular matrix called blood plasma.
Q: What percentage of body weight does blood constitute?
A: 8%
Q: What is the main component of blood plasma?
A: Water (91.5%)
Q: What percentage of blood plasma is made up of proteins, and what are the main types?
A: 7% proteins, including:
Albumins (54%): Helps with water balance
Globulins (38%): Includes immune proteins like antibodies
Fibrinogen (7%): Important for clotting
Q: What does the remaining 1.5% of blood plasma consist of?
A: Solutes, including electrolytes, nutrients, gases, hormones, and waste products.
Q: What are the formed elements in blood, and what percentage does it make up?
A: Formed elements make up 45% of blood and include red blood cells, white blood cells, and platelets.
Q: How many red blood cells are typically found per microliter of blood?
A: 4.8–5.4 million.
Q: What are the main types of white blood cells and their functions?
A:
Neutrophils (60–70%): Fight bacteria
Lymphocytes (20–25%): Handle specific immunity (e.g., viruses)
Monocytes (3–8%): Clean up debris and fight infection
Eosinophils (2–4%): Fight parasites and allergies
Basophils (0.5–1%): Involved in inflammation and allergic responses
Hint: NeverLetMonkeysEscapeBali
Q: How many platelets are typically found per microliter of blood, and what is their role?
A: 150,000–400,000 platelets help with blood clotting.
Q: What is erythropoiesis?
A: The process of red blood cell production that occurs in red bone marrow
Q: What is EPO and what does it do?
A: Erythropoietin (EPO) is a hormone released by kidneys that stimulates red blood cell production
Q: What is the process of RBC development?
A:
1. Begins with proerythroblasts in bone marrow
2. Cells divide and produce hemoglobin
3. Cells eject nucleus to become reticulocytes
4. Reticulocytes enter bloodstream and mature into RBCs within 1-2 days
Q: What is hypoxia and what causes it?
A:
Hypoxia is low oxygen levels, caused by:
High altitudes
Anemia
Poor circulation
Q: What happens when the body detects hypoxia?
A:
1. Kidneys detect low oxygen
2. Release EPO
3. EPO stimulates bone marrow 4. More RBCs are produced
5. Oxygen levels return to normal
Q: What is the main function of hemoglobin in RBCs?
A: To carry oxygen to all cells and transport some carbon dioxide to the lungs
Q: Why do mature RBCs have a biconcave shape?
A: Because they eject their nucleus during development
Q: How many iron ions does each hemoglobin molecule contain?
A: 4 iron ions, allowing it to bind 4 oxygen molecules.
Q: What are the main structural features of red blood cells (RBCs)?
A:
No nucleus
No mitochondria or organelles
Biconcave discs
Q: Why do RBCs lack a nucleus and mitochondria?
A: To maximize space for hemoglobin (approximately 280 million hemoglobin molecules per cell) and to carry oxygen more efficiently.
Q: What is the primary function of red blood cells?
A: To transport oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs.
Q: How does hemoglobin transport carbon dioxide?
A: It carries 23% of carbon dioxide by binding to the globin part of hemoglobin, with most CO₂ dissolved in plasma or as bicarbonate.
Q: What triggers the release of erythropoietin (EPO)?
A: Hypoxia (low oxygen levels in tissues).
Q: What is the role of nitric oxide (NO) in relation to hemoglobin?
A: Hemoglobin binds NO, and when released, NO causes vasodilation, improving blood flow and oxygen delivery.
Q: Describe the structure of hemoglobin.
A: It consists of 4 polypeptide chains (2 alpha and 2 beta), each with a heme group containing an iron ion (Fe²⁺) that binds oxygen.
Q: What happens to oxygen in the process of aerobic respiration?
A: Oxygen released by RBCs enters interstitial fluid and is utilized by cells for aerobic respiration in mitochondria.
Q: What is the shape of a red blood cell (RBC), and why is it important?
A: RBCs are biconcave discs, which increase surface area for oxygen exchange and allow them to squeeze through narrow blood vessels.
Q: What is the size of a typical red blood cell (RBC)?
A: About 8 µm in diameter.
Q: What protein is packed inside RBCs, and how many molecules are present in an RBC?
A: Hemoglobin; each RBC contains about 280 million hemoglobin molecules.
Q: What is the structure of hemoglobin?
A:
Made of 4 polypeptide chains:
2 alpha chains
2 beta chains
Each chain has a heme group.
Q: What is found at the center of the heme group in hemoglobin?
A: An iron ion (Fe²⁺) that binds oxygen.
Q: How many oxygen molecules can each hemoglobin molecule carry, and why?
A: 4 oxygen molecules, since each heme group (4 per hemoglobin) can bind one oxygen molecule.
Q: What surrounds the iron ion in the heme group?
A: A porphyrin ring, made of carbon and nitrogen.
Q: What happens to oxygen bound to hemoglobin?
A: It is taken up in the lungs and released into tissues where needed for cellular respiration.
Q: How does hemoglobin help regulate blood flow?
A: Through the binding and release of nitric oxide (NO), which causes vasodilation when released.
Q: What are the benefits of NO-induced vasodilation?
A:
Improved blood flow
Enhanced oxygen delivery
Reduced blood pressure
Q: Where does carbon dioxide come from in the body?
A: From cellular respiration (metabolism) when cells break down nutrients for energy.
Q: How is carbon dioxide transported in the blood?
A:
23% binds to hemoglobin
Most dissolves in blood plasma as bicarbonate ions
Q: What is the pathway of CO₂ from cells to elimination?
A:
1. Produced by cellular metabolism
2. Moves into interstitial fluid
3. Enters bloodstream
4. Transported to lungs
5. Exhaled during breathing
Q: What is blood doping?
A: Increasing RBC count to enhance athletic performance by improving oxygen delivery to muscles.
Q: What are the risks of artificial blood doping?
A:
Increased blood viscosity
Higher blood pressure
Increased risk of strokes
Makes it harder for heart to pump blood
Q: How long do red blood cells live and why?
A: About 120 days; they die due to plasma membrane wear and tear and inability to repair (no nucleus).
Q: Which organs remove dead RBCs from circulation?
A: The spleen, liver, and red bone marrow (via macrophages).
Q: What happens to the globin part of hemoglobin during breakdown?
A: It’s broken down into amino acids, which are recycled to make new proteins.
Q: What happens to the iron from heme during RBC breakdown?
A:
1. Iron is removed (as Fe³⁺)
2. Binds to transferrin for transport
3. Stored in ferritin in liver or muscle
4. Reused in bone marrow for new RBC production
Q: What happens to the non-iron portion of heme?
A: Converted to:
Biliverdin (green pigment)
Then to bilirubin (yellow pigment)
Q: What is the pathway of bilirubin breakdown?
A: 1. Transported to liver 2. Released into bile 3. Moves to intestines 4. Converted to urobilinogen by bacteria 5. Either absorbed back into blood (becomes urobilin in urine) or becomes stercobilin in feces
Q: What gives urine its yellow color?
A: Urobilin (from urobilinogen)
Q: What gives feces its brown color?
A: Stercobilin (from urobilinogen)
Q: What is hematocrit (Hct)?
A: The percentage of total blood volume that is composed of red blood cells.
Q: What are the normal hematocrit ranges?
A:
Females: 38-46% (average 42%)
Males: 40-54% (average 47%)
Q: Why is a hematocrit of 60% or higher dangerous?
A: - Makes blood too thick
Harder for heart to pump
Increases blood pressure
Higher risk of stroke
Slows blood flow
Q: What are two main causes of high hematocrit?
A: 1. Dehydration 2. EPO injection (blood doping)
Q: How does blood thickness affect the body?
A: - Affects blood flow rate through vessels
Impacts oxygen delivery to tissues
Influences cardiovascular health
Affects how hard the heart must work
Q: What determines blood thickness?
A: The ratio between:
Blood plasma (liquid component)
Formed elements (mainly RBCs) Higher concentration of formed elements = thicker blood
Q: What are the risks of artificially increasing hematocrit through EPO?
A: - Increased blood viscosity
Higher blood pressure
Increased stroke risk
Greater strain on heart
Compromised blood flow
Q: What is the normal state of blood composition?
A: A balanced ratio between plasma (liquid) and red blood cells, resulting in normal viscosity and flow.
Q: What happens to blood composition during water loss?
A:
Water leaves blood vessels
Plasma volume decreases
RBC concentration increases relatively
Blood becomes more concentrated
Q: What is hemoconcentration?
A: A condition where blood becomes thicker due to reduced plasma volume while RBC numbers remain the same, resulting in a higher concentration of RBCs.
Q: What are the effects of hemoconcentration?
A:
Increased blood viscosity
Harder for heart to pump blood
Slower blood flow
Increased strain on cardiovascular system
Q: What causes hemoconcentration?
A: Primary cause is dehydration or fluid loss from the blood vessels.
Q: Why is hemoconcentration dangerous?
A:
Makes blood harder to pump through vessels
Increases work for the heart
Can reduce oxygen delivery to tissues
May increase risk of blood clots
Q: How can hemoconcentration be prevented?
A: By maintaining proper hydration and fluid balance in the body.
Q: What are the key characteristics of white blood cells?
A:
Contain nucleus and organelles
No hemoglobin
Part of immune system
Can leave bloodstream to fight infection
Q: What does an elevated white blood cell count usually indicate?
A: Usually indicates infection or inflammation in the body.
Q: What are the main types of white blood cells?
A:
Lymphocytes
Neutrophils
Monocytes
Eosinophils
Basophils
Q: What is the primary function of white blood cells?
A:
To defend the body against infections and diseases by:
Identifying pathogens
Attacking invaders
Producing antibodies
Developing immune memory
Q: What are platelets and their main function?
A: Platelets (thrombocytes) are cell fragments that help blood clot to prevent excessive bleeding.
Q: How do platelets work to stop bleeding?
A: 1. Adhere to injury site 2. Form temporary plug 3. Release chemicals to attract more platelets 4. Activate clotting cascade
Q: Where do platelets come from?
A: They originate from larger cells in bone marrow called mega.kary.ocytes.
Q: What is the key difference between WBCs and platelets?
A: WBCs focus on immune defense against disease, while platelets focus on blood clotting and preventing blood loss.
Q: How are blood groups classified?
A: Based on the presence or absence of glycoprotein and glycolipid antigens on the surface of red blood cells.
Q: What are the four main blood types in the ABO system?
A:
1. Type A
2. Type B
3. Type AB
4. Type O
Q: What characterizes Type A blood?
A: Has A antigens on the surface and contains anti-B antibodies in plasma.
Q: What characterizes Type B blood?
A: Has B antigens on the surface and contains anti-A antibodies in plasma.
Q: What does Type AB blood contain?
A: Both A and B antigens and no anti-A or anti-B antibodies, making it the universal recipient.
Q: What characterizes Type O blood?
A: Lacks A and B antigens, contains both anti-A and anti-B antibodies, and can donate to anyone (universal donor).
Q: Why is matching blood types crucial during transfusions?
A: Mismatched blood can trigger an immune response against foreign antigens, leading to severe reactions or death.
Q: Why is it important to understand blood types?
A: It ensures safe blood transfusions and organ transplants, preventing catastrophic immune reactions.
Q: What does red coloring represent in circulatory diagrams?
A:
Oxygen-rich blood
Arteries carrying blood from heart to body
Blood that has passed through lungs
Contains oxygenated hemoglobin
Q: What does blue coloring represent in circulatory diagrams?
A: - Oxygen-poor (deoxygenated) blood
Veins returning blood to heart
Blood that needs reoxygenation
Contains deoxygenated hemoglobin
Q: What are the two main circulatory paths?
A: 1. Pulmonary Circulation (Heart ↔ Lungs) 2. Systemic Circulation (Heart ↔ Body)
Q: List blood vessels from largest to smallest diameter:
A: 1. Vena Cava/Aorta (2.5-3.0 cm) 2. Veins (3.0 cm) 3. Arteries (0.5 cm) 4. Arterioles (30 µm) 5. Capillaries (6 µm)
Q: What is the function of arterioles?
A: Control blood flow into capillaries by constricting or dilating their smooth muscle walls.
Q: What is the main function of capillaries?
A: Allow exchange of oxygen, nutrients, and waste products between blood and tissues through their thin walls.
Q: How do veins differ from arteries?
A: - Thinner walls
Larger diameter
Carry blood under lower pressure
Return oxygen-poor blood to heart
Q: What are the two major divisions of circulation?
A: 1. Pulmonary circulation (right side of heart) 2. Systemic circulation (left side of heart)
Q: What is the purpose of pulmonary circulation?
A: To carry deoxygenated blood to the lungs for gas exchange (remove CO₂ and pick up O₂)
Q: What is the purpose of systemic circulation?
A: To supply oxygenated blood to all tissues of the body and return deoxygenated blood to the heart
Q: Describe the pathway of pulmonary circulation:
A:
1. Right heart → pulmonary trunk
2. Pulmonary arteries → lungs
3. Gas exchange in pulmonary capillaries
4. Pulmonary veins → left atrium
Q: Describe the pathway of systemic circulation:
A: 1. Left heart → aorta
2. Systemic arteries → arterioles → capillaries
3. Gas exchange with tissues
4. Venules → systemic veins → right atrium
Q: Where does gas exchange occur in both circuits?
A: In the capillaries:
Pulmonary capillaries (in lungs)
Systemic capillaries (in body tissues)
Q: What type of blood does each side of the heart pump?
A:
Right side: Pumps deoxygenated blood (pulmonary circuit)
Left side: Pumps oxygenated blood (systemic circuit)
Q: Why is circulation described as a “Figure 8” type circuit?
A: Because blood flows in two continuous, connected loops: one through the lungs (pulmonary) and one through the body (systemic)
Q: What is the primary function of arteries?
A: Arteries carry blood away from the heart. In pulmonary circulation, the pulmonary artery moves deoxygenated blood to the lungs.
Q: What is the primary function of veins?
A: Veins carry blood toward the heart, returning oxygen-rich blood from the lungs and body back to the heart.
Q: Where does gas exchange occur in the circulatory system?
A: In the capillaries, where oxygen (O₂) is delivered to tissues, and carbon dioxide (CO₂) is picked up for transport back to the lungs.
Q: What are the four chambers of the heart?
A:
Two Atria: Left and right atria receive blood and pump it into the ventricles.
Two Ventricles: Left and right ventricles pump blood throughout the body.
Q: What is the function of the left ventricle?
A: The left ventricle pumps oxygenated blood to the entire body and has larger and stronger muscle walls (4x stronger than the right ventricle).
Q: What is the function of the right ventricle?
A: The right ventricle pumps deoxygenated blood to the lungs for oxygenation.
Q: How do heart valves work?
A: They open and close in response to pressure changes as the heart contracts and relaxes, preventing backflow of blood.
Q: What are the right and left atrioventricular (AV) valves?
A:
Right AV Valve: Tricuspid valve
Left AV Valve: Bicuspid (or mitral) valve
These valves prevent backflow from the ventricles into the atria.
Q: What are the right and left semilunar valves?
A: These valves prevent backflow from the arteries into the ventricles:
Right Semilunar Valve: Pulmonary valve
Left Semilunar Valve: Aortic valve
Q: Describe the pulmonary circulation pathway (blue path):
A: 1. Right atrium receives deoxygenated blood 2. Through tricuspid valve to right ventricle 3. Through pulmonary valve to pulmonary arteries 4. To lungs for gas exchange 5. Returns via pulmonary veins
Q: Describe the systemic circulation pathway (red path):
A: 1. Left atrium receives oxygenated blood 2. Through mitral valve to left ventricle 3. Through aortic valve to aorta 4. To body tissues via systemic arteries 5. Returns via venae cavae
Q: Where does deoxygenated blood enter the right atrium from?
A:
Superior vena cava
Inferior vena cava
Coronary sinus
Q: What happens in the pulmonary capillaries?
A:
Blood:
Loses carbon dioxide (CO₂)
Gains oxygen (O₂)
Q: What happens in the systemic capillaries?
A:
Blood:
Delivers oxygen (O₂) to tissues
Picks up carbon dioxide (CO₂)
Q: What is the role of the left ventricle?
A: The largest and strongest chamber, pumps oxygenated blood through the aortic valve into the aorta for distribution to the body.
Q: Where does gas exchange occur in both circuits?
A:
Pulmonary circuit: In lung capillaries
Systemic circuit: In tissue capillaries
Q: How do the two circulation loops work together?
A: They form a continuous circuit:
Pulmonary: Heart → lungs → heart
Systemic: Heart → body → heart
Q: What is Cardiac Output (CO) and how is it calculated?
A:
Volume of blood ejected from ventricles per minute
Formula: CO = Stroke Volume (SV) × Heart Rate (HR)
Units: mL/min = mL/beat × beats/min
Q: What are normal cardiac output values?
A:
At rest: 4-6 L/min
During exercise: 26-28 L/min
Q: What is Stroke Volume (SV)?
A: The amount of blood pumped out of the ventricle in one beat.
Q: What factors affect Stroke Volume?
A: 1. Preload (blood filling before contraction) 2. Contractility (strength of contraction) 3. Afterload (pressure heart must overcome)
Q: How does the nervous system regulate heart rate?
A:
Through the Autonomic Nervous System:
Sympathetic: Increases HR (during activity/stress)
Parasympathetic: Decreases HR (at rest)
Q: How do hormones affect heart rate?
A:
Hormones from adrenal medulla:
Epinephrine (adrenaline)
Norepinephrine Both increase heart rate and contractility
Q: What happens to cardiac output during exercise?
A: Increases significantly to supply muscles with more oxygen and nutrients through:
Increased heart rate
Increased stroke volume
Q: How does the body compensate for reduced stroke volume?
A:
Increases heart rate
Increases contractility
Goal: Maintain adequate cardiac output
Q: What is the SA node and its function?
A: - Primary pacemaker of the heart
Initiates and sets heart rate
Fires 60-100 times per minute
Located in right atrium
Q: What is the AV node and its function?
A: - Secondary pacemaker (40-60 times/min)
Acts as electrical gateway to ventricles
Delays impulse briefly before transmission to ventricles
Q: What are the bundle branches?
A: - Right and left branches
Carry action potential from AV node
Conduct electrical signal to respective ventricles
Q: What are Purkinje fibers and their function?
A: Terminal conducting fibers
Spread action potential throughout ventricle walls
Enable coordinated ventricular contraction
Q: Describe the sequence of cardiac conduction:
A: 1. SA node creates action potential 2. Signal travels across atria 3. Reaches AV node 4. Travels through bundle branches 5. Spreads via Purkinje fibers 6. Results in ventricular contraction
Q: What happens when the action potential reaches the atrial walls?
A: The atria contract, pushing blood into the ventricles
Q: What is the final result of the action potential reaching Purkinje fibers?
A: Complete ventricular contraction, pumping blood out of the heart
Q: What is an action potential in the heart?
A: A wave of positive electrical charge that triggers heart muscle contraction
Q: What is an ECG and what does it measure?
A: - A non-invasive medical test
Records heart’s electrical activity
Shows heart rhythm and function
Used to diagnose cardiac conditions
Q: What does the P wave represent?
A: - Represents atrial depolarization
Shows when atria contract
Appears as small rounded bump
Function: Atria pump blood into ventricles
Q: What is the P-Q interval?
A: - Time between P wave and QRS complex
Shows signal travel time from atria to ventricles through AV node
Allows ventricles to fill with blood completely
Q: What is the QRS complex?
A: - Represents ventricular depolarization (contraction)
Appears as large spike
Larger due to ventricle size and muscle mass
Stronger electrical signal
Q: What is the S-T segment?
A: - Period between depolarization and repolarization
Shows time when ventricles are fully contracted
Appears as flat line
Located after QRS complex
Q: What does the T wave represent?
A: - Shows ventricular repolarization
Ventricles reset electrically
Prepares for next contraction
Appears as rounded bump after QRS
Q: What is the Q-T interval?
A: Total time from start of Q wave to end of T wave, showing complete ventricular depolarization and repolarization cycle
Q: What are the clinical uses of ECG?
A: Helps diagnose:
Heart rhythm abnormalities
Heart attacks
Other cardiac conditions
Monitors heart health
Guides treatment decisions
Q: What is the relationship between depolarization and contraction?
A: - Depolarization = Contraction
Repolarization = Relaxation
Q: What happens during atrial depolarization?
A: 1. SA node sends electrical signal 2. Atria begin to contract 3. Blood moves into ventricles 4. Appears as P wave on ECG
Q: What occurs during ventricular depolarization?
A: 1. Signal moves to ventricles (starts at apex) 2. Ventricles contract 3. Atria simultaneously repolarize (relax) 4. Appears as QRS complex on ECG
Q: Describe the complete sequence of electrical activity:
A: 1. SA node initiates signal 2. Atrial depolarization (P wave) 3. Ventricular depolarization (QRS complex) 4. Ventricular repolarization (T wave)
Q: What happens during the S-T segment?
A: - Short break between ventricular depolarization
Ventricles are fully contracted
Appears as flat line on ECG
Q: What does the T wave represent and what happens?
A: - Represents ventricular repolarization
Ventricles relax
Heart prepares for next cycle
Completes the heartbeat
Q: Where does ventricular depolarization begin?
A: - Starts at the apex (bottom) of the heart
Moves upward through ventricles
Creates characteristic QRS complex
Q: What ensures efficient blood pumping?
A: The coordinated sequence of:
Atrial contraction first (P wave)
Ventricular contraction (QRS)
Ventricular relaxation (T wave)
