2.3.1 - Transport Systems (basically cardiovascular)

Question 1

Transport systems (vascular and cardiovascular) have:

Answer 1

• System of vessels
• Transport medium (fluid)
• Mechanism to move fluids in required directions.

Question 2

Vascular plant transport systems

Answer 2

Sink-source theory:
* System: phloem, with pressure by xylem
* Medium: fluid from the xylem
* Mechanism: osmotic pressure gradient

Transpiration-tension-cohesion theory:
* System: xylem, with tension from leaves and roots
* Medium: water and water soluble nutrients
* Mechanism: tension and cohesion

Question 3

Practice question:
make a flow chart of the source-sink theory, wth a companion labelled diagram

Question 4

Cardiovascular system

Circuits, movement of oxygenated + deoxygenated blood, vessels

Answer 4

Pulmonary circuit takes deoxygenated blood to the lungs, and takes oxygenated blood from the lungs back to the heart
Systemic circuit takes oxygenated blood from the heart to the rest of the body and takes deoxygenated blood from the body back to the heart

Oxygenated blood is pumped through arteries Arteries take oxygenated blood to various parts of the body.
- Arteries branch into arterioles and then into capillaries
- Movement of blood slows down in the capillaries, allowing gas and nutrient exchange to occur

Deoxygenated blood moves from capillaires into venules (like arterioles but for veins) and then into veins.
- Movement of blood through veins relies on the contraction and expansion of muscles in and around the veins.

Question 5

Heart organ

Answer 5

Deoxygenated blood (right)
* Superior and inferior vena cava into the right atrium. (superior vena cava = blood from upper body; inferior vena cava = from lower body)
* To the right ventricle
* To the pulmonary artery through the pulmonary valves. (to the lungs)

Oxygenated blood (left)
* From the lungs to the left atrium through pulmonary veins
* Into the left ventricle, then pumped through aorta into the systemic circuit

Septum separates the left and right side of the heart, separating the deoxygenated and oxygenated blood.

Question 6

Comparison of muscular walls in cardiovascular system

Answer 6

• Thinner atrium walls, pumping just to the ventricle
• Thicker ventricle walls, to pump blood to all different parts of the body
• Arteries have thick muscular walls to sustain the pressure of the blood pumped from the heart

Question 7

Circulation

Answer 7

Systemic: oxygenated blood to all parts of the body, deoxygenated back to the heart

Pulmonary: from the lungs to the heart/from the heart to the lungs

Question 8

Blood makeup

Answer 8

• Red blood cells (40-50%)- transport substances
• White blood cells - immune defense
• Plasma (55-60%)- fluid, 90% water
• Platelets - blood clotting

Question 9

Red blood cell

Answer 9

• Formed in the bone marrow
• No nucleus: nucleus disintegrates to carry more haemolobin (oxygen carrier)
• Round biconcave shape to squeeze through capillaries
• Approx 7 microns wide

Question 10

White blood cell

Answer 10

• Has nucleus
• Leucocytes pass through capillaries by squeezing between cells that make up the wall of the capillaries to get to damaged cells to respond to pathogens
• 50% bigger than red blood cell and less abundant
• Approx 12 microns wide

Question 11

Platelets

Answer 11

• Formed in the bone marrow
• crescent-shaped, 1/2 size of RBC
• Stick together and to the fibres that develop at the site of a wound when blood is exposed to air
• Contact between fibres and platelets causes platelets to break open and produce a enzyme, thromboplastin, which catalyses the process of clotting

Question 12

Blood vessels

Answer 12

Arteries (a-way from the heart):
* High pressure, fast moving blood
* Thus, thick elastic vessel walls, no valves.
* This ensures that large surges can’t reach the smaller vessels where they would cause damage.

Veins (towards the heart):
* deoxygenated blood (pulmonary: oxygenated to the heart
* Low pressure and slower moving blood: 1/12th the pressure in arteries.
* Valves to prevent backflow of deoxygenated blood, especially in the lower body such as the legs.
* thin vessel walls.

Capillaries: connecting arteries to veins
* Very thin, only one RBC at a time. Optimises diffusion for substance exchange
* Exchange substances to body cells and carry oxygenated and deoxygenated blood

Question 13

Plasma

Answer 13

90% water, 10% proteins

In addition to carrying RBC, they carry:
* Plasma proteins (e.g. clotting factors, antibodies, enzymes),
* Nutrients
* Ions
* Excretory wastes
* Regulatory substances (e.g. hormones)
* Other (e.g. vitamins)

Question 14

Pathway through the circulatory system

Answer 14

1. Vena cava
2. Right atrium
3. Tricuspid
4. Right ventricle
5. Pulmonary valve
6. Pulmonary artery
7. Lungs
8. Pulmonary vein
9. Left artium
10. Mitral valve
11. Left ventricle
12. Aortic valve
13. Aorta