Lecture 11: Moving Nutrients - Closed Systems and Other Methods

Question 1

What is the circulatory system in mammals and birds?

Answer 1

Double circulatory system

Question 2

What is laminar flow?

Answer 2

Laminar flow is when fluid flows in parallel layers without disruption (no turbulence).

1. The velocity of the external layer is low.
2. The velocity of the internal layer is high.

Question 3

How does velocity depend on Poiseuille’s law?

Answer 3

Blood flow is fastest in aorta and slowest in capillary beds.

Question 4

What is systole?

Answer 4

Blood has high pressure in the aorta aka ventricular contraction.

Question 5

What is diastole?

Answer 5

Blood has low pressure. Refilling of blood after systole and pressure maintained by recoil.

Question 6

How do you classify systole and diastole in 120/80 blood pressure?

Answer 6

120 is systolic pressure and 80 is diastolic pressure. 120/80 is not a ratio.
Unit is mmHg.

Question 7

What is the relationship between net flow and linear velocity?

Answer 7

Net flow is unchanged but linear velocity is minimal.

Question 8

What does microcirculation determine?

Answer 8

Microcirculation determines overall peripheral resistance.

Question 9

What is the microcirculatory bed?

Answer 9

Arterioles control capillary flow while blood flow is constant. There is a smooth muscle contraction caused by large vessels due to blood pressure.

Question 10

What is vasoconstriction?

Answer 10

Increased smooth muscle contraction, leading to increased resistance and decreased flow through vessel.

Question 11

What is vasodilation?

Answer 11

Decreased smooth muscle contraction, leading to decreased resistance and increased flow through vessel.

Question 12

What is hydrostatic pressure?

Answer 12

Hydrostatic pressure decreases through capillaries.

Question 13

What is oncotic pressure?

Answer 13

Oncotic (similar to osmotic) pressure is distinguished in the capillary bed, so it stays constant. Osmotic pressure depends on plasma proteins (oncotic pressure) because capillaries are permeable to ions.

Question 14

What do insects and arthropods have in common?

Answer 14

They have an open circulatory system.

Question 15

Why are accessory pulsatile organs or ampulla (Amp) necessary?

Answer 15

They are necessary for appendages to circulate because there is high resistance from the radius and low pressure of the open system.

Question 16

What is the difference between xylem and phloem?

Answer 16

Xylem moves water and minerals, and it has a unidirectional flow from roots to leaves. Phloem moves photosynthate and other materials, and it has a bidirectional flow from sources to sinks.

Question 17

In what plants do xylem and phloem occur?

Answer 17

Xylem and phloem occur in vascular bundles in herbaceous plants. Xylem is the heartwood in woody plants.

Question 18

Describe the structure and function of xylem.

Answer 18

Xylem has dead cells. The two systems of xylem are tracheids and vessel elements.

Tracheids are long with primary wall (cellulose) and secondary wall (lignin), and they have a high surface-to-volume ratio. A non uniform lignin is called pits.

Vessel elements are short with perforation plates that connect cells in a common structure. Vessels need constant pressure to maintain water cohesion.

Question 19

What is the cohesion-tension theory?

Answer 19

Evapotranspiration and water cohesion pull water from roots to shoots. Xylem sap is under negative pressure. Transpiration from leaf pulls water in xylem.

Question 20

What are the sieve elements and companion cells of the phloem?

Answer 20

Sieve elements are cells with tubes. Companion cells are together and move sugars.

Question 21

What is a phloem sap?

Answer 21

A phloem sap is an aqueous solution with high sucrose.

Question 22

What is translocation (process that moves phloem)?

Answer 22

1. Sources actively or passively load carbon molecules.
2. Water comes after osmosis to increase hydrostatic pressure.
3. Sugar is unloaded at the sink.