Circulatory system

Question 1

What are the functions of the circulatory system?

Answer 1

Transport oxygen/nutrients, remove CO₂ and waste, carry hormones, maintain pH and water/ion balance, regulate body temperature, protect against disease, and clot to prevent blood loss.

Question 2

What is the normal body temperature regulated by the circulatory system?

Answer 2

37°C.

Question 3

How much blood does a woman typically have?

Answer 3

4-5 litres.

Question 4

How much blood does a man typically have?

Answer 4

5-6 litres.

Question 5

What percentage of blood is plasma?

Answer 5

55%

Question 6

What is plasma mostly made of?

Answer 6

91% water and 9% dissolved substances (like O₂, CO₂, nutrients, waste).

Question 7

What are the formed elements in blood?

Answer 7

Red blood cells(erythrocytes), white blood cells(leukocytes), and platelets(thrombocytes) 45% of blood volume.

Question 8

What shape are red blood cells?

Answer 8

Biconcave.

Question 9

What percentage of blood volume do RBCs make up?

Answer 9

40–45% (hematocrit).

Question 10

Why don’t RBCs have nuclei?

Answer 10

More room for haemoglobin and increased flexibility.

Question 11

How long do RBCs live?

Answer 11

About 120 days.

Question 12

What is the main function of WBCs?

Answer 12

Remove dead/injured cells and protect against infection.

Question 13

Where are WBCs made?

Answer 13

Bone marrow, spleen, lymph nodes, and thymus.

Question 14

What are lymphocytes?

Answer 14

WBCs involved in immune response.

Question 15

What are platelets?

Answer 15

Small cell fragments with no nucleus, involved in clotting.

Question 16

How long do platelets live?

Answer 16

About 7 days.

Question 17

What happens during vasoconstriction?

Answer 17

Arterioles constrict to reduce blood flow after injury.

Question 18

What is a platelet plug?

Answer 18

Platelets stick to the vessel wall and each other to block a hole.

Question 19

What is coagulation?

Answer 19

Blood clotting with RBCs, platelets, and fibrin to form a thrombus.

Question 20

What is clot retraction?

Answer 20

Fibrin contracts, drying to form a scab.

Question 21

How is oxygen transported in the blood?

Answer 21

3% dissolved in plasma, 97% bound to haemoglobin (oxyhaemoglobin).

Question 22

What makes RBCs ideal for transporting oxygen?

Answer 22

No nucleus and biconcave shape.

Question 23

What color is oxygenated blood?

Answer 23

Bright red (in arteries, except pulmonary artery).

Question 24

What color is deoxygenated blood?

Answer 24

Dark red or purple (in veins, except pulmonary vein).

Question 25

How is CO₂ transported in blood?

Answer 25

7-8% dissolved in plasma, 22% on haemoglobin (carbaminohaemoglobin), 70% as bicarbonate ions.

Question 26

What is the chemical formula for CO₂ transport as bicarbonate?

Answer 26

CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻.

Question 27

What nutrients are transported in plasma?

Answer 27

Glucose, amino acids, vitamins.

Question 28

What inorganic substances are transported?

Answer 28

Na⁺, K⁺, Ca²⁺ ions.

Question 29

What are some metabolic wastes?

Answer 29

Urea, creatinine, uric acid.

Question 30

What muscle type is the heart made of?

Answer 30

Cardiac muscle.

Question 31

Where is the heart located?

Answer 31

In the mediastinum, behind and slightly left of the sternum.

Question 32

What surrounds the heart and why?

Answer 32

The pericardium; it anchors, protects, and allows movement.

Question 33

What are the heart’s upper chambers?

Answer 33

Atria (right and left).

Question 34

What are the heart’s lower chambers?

Answer 34

Ventricles (right and left).

Question 35

Trace the flow of blood through the heart.

Answer 35

Body → Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Body.

Question 36

Why is the left ventricle wall thicker?

Answer 36

It pumps blood to the entire body.

Question 37

What do heart valves do?

Answer 37

Ensure one-way blood flow.

Question 38

What are atrioventricular valves supported by?

Answer 38

Chordae tendineae attached to papillary muscles.

Question 39

What do semi-lunar valves do?

Answer 39

Control flow into the aorta and pulmonary artery.

Question 40

What causes the 'lub-dub' sound?

Answer 40

Valve closure.

Question 41

What are the 3 types of blood vessels?

Answer 41

Arteries, veins, and capillaries.

Question 42

What do arteries do?

Answer 42

Carry blood away from the heart. (high pressure)

Question 43

What's the largest artery in the body?

Answer 43

Aorta

Question 44

What is vasoconstriction?

Answer 44

The vessel walls contract reducing blood flow.

Question 45

What is vasodilation?

Answer 45

Vessel walls widen to increase blood flow.

Question 46

What do capillaries do?

Answer 46

Connect arteries and veins; allow exchange of substances from capillary to cell and vice versa.

Question 47

Why do veins have valves?

Answer 47

to prevent backflow due to the absence of pressure.

Question 48

Major veins linking to the right atrium?

Answer 48

inferior vena cava (ascending from below heart) and superior vena cava (descending from above heart)

Question 49

What happens during exercise?

Answer 49

cells produce more C02/lactic acid -> vasodilation to remove waste -> increase heart rate to increase cardiac output

Question 50

What are the two phases of the cardiac cycle?

Answer 50

systole (contraction) and diastole (relaxation)

Question 51

What happens during one heartbeat?

Answer 51

Diastole → Atrial systole → Ventricular systole.

Question 52

What is cardiac output?

Answer 52

The volume of blood the heart pumps in a given time?

Question 53

Blood group compatibility?

Answer 53

o- -> all o+ -> all + a- -> a-+, ab-+ a+ -> a+, ab+ b- -> b-+, ab-+ b+ -> b+, ab+ ab- -> ab-+ ab+ -> ab+

Question 54

Steps of clotting?

Answer 54

1. vasoconstriction to reduce blood flow to the area 2. Thrombocytes adhere to the exposed collagen in the vessel wall to form a platelet plug 3. coagulation occurs RBCs and platelets against the wall have a protein fibrin mesh that incases them against the wall form a thrombus 4. Clot retraction; fibrin retracts and the clot dries to form a scab

Question 55

Cardiac cycle?

Answer 55

1. both atria and ventricles in diastole (ventricle filling SL close AV open) 2. Atrial systole (and ventricular diastole) SL close remainng blood to RLV 3. Ventricular systole (and atrial diastole) AV close SL open pump out LA blood go in at RA

Question 56

Blood transfusions:?

Answer 56

Whole blood, RBC concentrate, Plasma, Platelet, cryoprecipitate (Frozen plasma), immunoglobulins, autologous (blud to yourself)

Question 57

agglutination?

Answer 57

erythrocytes clumping together example is a haemolytic disease at birth mother rh- baby is rh+ first go good anymore children die die