Circulatory System

Question 1

Purpose of the Circulatory System

Answer 1

Achieve mass movement of molecules around the body

Question 2

Source

Answer 2

a place in the body where molecules enter the bloodstream

Question 3

Sink

Answer 3

a place in the body where molecules leave the bloodstream

Question 4

Oxygen Source

Answer 4

Alveoli

Question 5

Oxygen Sink

Answer 5

All living cells

Question 6

Carbon Dioxide Source

Answer 6

All living cells

Question 7

Carbon Dioxide Sink

Answer 7

Alveoli

Question 8

Glucose Source

Answer 8

Small Intestines

Question 9

Glucose Sink

Answer 9

All living cells

Question 10

Urea Source

Answer 10

All living cells

Question 11

Urea Sink

Answer 11

Kidneys

Question 12

Why do large organisms need a circulatory system?

Answer 12

Molecules have a further distance to travel. Large organisms need large amounts of oxygen, glucose, water etc to survive. Requires mass movement

Question 13

Pulmonary Artery

Answer 13

Blood flows into lungs from heart (deoxygenated) high pressure

Question 14

Pulmonary Vein

Answer 14

Blood flows to the heart from the lungs (oxygenated) low pressure

Question 15

Vena Cava

Answer 15

Blood flows to heart from body (deoxygenated) low pressure

Question 16

Aorta

Answer 16

Blood flows to body from heart (oxygenated) highest pressure

Question 17

Bit separating the two sides of the heart

Answer 17

Septum

Question 18

Chamber with highest pressure

Answer 18

Left Ventricle (therefore has thicker walls to generate and cope with pressure)

Question 19

Chamber with lowest pressure

Answer 19

Right Atrium (thinner walls as doesn’t need to cope with high pressure)

Question 20

Structure of Arteries

Answer 20

Thick elastic walls to cope with high blood pressure. Small lumen

Question 21

Structure of Veins

Answer 21

Thin, less stretchy walls as they don’t need to cope with high pressure. Large lumen

Question 22

How do some veins allow blood flow against gravity?

Answer 22

Muscle tissue lining to contract and push blood and valves to stop blood flow in wrong direction

Question 23

Heart Strings

Answer 23

Keep valves from opening the wrong way and letting blood flow in wrong direction

Question 24

Valves between atria and ventricles

Answer 24

Atrio-ventricular Valves

Question 25

Valves between ventricles and arteries

Answer 25

Semi-lunar Valves

Question 26

Cardiac Cycle

Answer 26

Sequence of events during one heartbeat

Question 27

Cardiac Cycle steps

Answer 27

Atrial Systole → Ventricular Systole → Diastole

Question 28

Atrial Systole

Answer 28

Atrium walls contract to push blood through atrio-ventricular valves. Blood flows into ventricles. swoosh

Question 29

Ventricular Systole

Answer 29

Ventricle walls contract to push blood through semi-lunar valves. Blood flows into arteries. BOOM

Question 30

Diastole

Answer 30

Both atria and ventricles relax to lower blood pressure inside the heart to draw new blood in from veins. boom

Question 31

Structure of Capillaries

Answer 31

Single-cell walls. Very small lumen

Question 32

Structure of Arterioles

Answer 32

Smooth muscle rings to contract and slow down blood for diffusion. Redirect blood to prioritised organs during exercise.

Question 33

Composition of Blood

Answer 33

- 54% plasma - 1 % buffy coat (wbc + platelettes) - 45% red blood cells

Question 34

Red Blood Cells

Answer 34

Carry oxygen around body using haemaglobin

Question 35

White Blood Cells

Answer 35

Responsible for defense against disease

Question 36

Platelettes

Answer 36

Tiny cell fragments responsible for clotting blood

Question 37

Plasma

Answer 37

Transports cells in blood - urea, water, salt, rbc, wbc, platelettes, hormones, fats, amino acids, glucose, anitbodies, plasma proteins

Question 38

How are red blood cells adapted to their function?

Answer 38

- packed with haemoglobin - no internal organelles (more room for haemoglobin) - biconcave disc shape (high SA:vol ratio + short diffusion distance for oxygen) - small (travel in billions)

Question 39

Types of WBC

Answer 39

- phagocytes | lobed nucleus | engulf + digest pathogens - lymphocytes | large central nucleus | produce antibodies to enhance immune response