Human Transport

Functions

• Pumps blood in one direction

• Keeps oxygen rich and oxygen poor blood separate

• Supplies blood pressure

• Supplies every cell in the body with blood

Chambers of the Heart • Superior Chambers

– Right Atrium

– Left Atrium

• Inferior Chambers

– Right Ventricle

– Left Ventricle

Tricuspid Valve – 3 flaps

Right Heart

• Deoxygenated blood enters Right atrium

• Into right ventricle

• Into the pulmonary arteries

• To the lungs

Left Heart

• Oxygen rich blood back to the heart from the lungs through the pulmonary veins

• Into the Left Atrium

• Into the Left Ventricle

Left Heart

• Blood is forced from the left ventricle out the Aorta

Blood Flow through the Heart • Deoxygenated blood flows

from IVC, SVC into right atrium • Right a/v valve (tricuspid) • Right ventricle • Pulmonary semilunar Valve • Pulmonary artery • Lungs • Pulmonary vein • Left atrium • Left a/v valve (bicuspid) • Left ventricle • Aortic semilunar Valve • Oxygenated blood flows out of

Aorta to rest of body

Operation of Heart Valves

Slide 11.10

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.4

Blood Flow

• All arteries branch FROM the aorta

• All veins branch INTO the Superior and Inferior Vena Cava

Pulmonary Gas Exchange

Gas Exchange

Conduction System of the Heart • Intrinsic conduction system: heart contracts

automatically

• Heart beats about 2.5 billion times in a lifetime

• About 5 liters of blood is recycled in a heart beat!

Conduction System… The Pacemaker

• Near upper posterior wall of the right atrium

• Pacemaker of the heart

• Initiates heartbeat and the atria contract

http://tech.snmjournals.org/content/vol34/issue4/images/large/193fig18.jpeg

Now, on to the Cardiac Cycle…

• All the events that occur in one heartbeat

• Average Heart Rate = 70 beats/minute

– Range 60-100 beats/minute

• Both sides of the heart contract together

Overview of the Cardiac Cycle Systole: Contraction of the heart muscle

• First, both atria contract

• Then, both ventricles contract

Diastole: Relaxation of the heart muscle

• Both atria relax

• Followed by the relaxation of both ventricles

EKG (ECG)

• Electrocardiogram

• Records the electrical activity of the heart muscle

EKG (ECG)

• P wave: Atria (contract)

• QRS complex: Ventricles contract

• T wave: ventricles relax

Reading and EKG

Arrhythmias

• Bradycardia

– HR of fewer than 60 beats/minute

• Tachycardia

– HR of more than 100 beats/minute

• Fibrillation

– Rapid uncoordinated beating

Blood Vessels

• Many layers of tissue

• Blood flows through the lumen

Arteries VS. Veins

• Carry blood away from the heart

• Small arteries = arterioles • Thick walls • largest arteries are about as

thick as a thumb • Blood rich in oxygen

– Except pulmonary arteries

• Flows under high pressure (highest in aorta because close to left Ventricle)

• No valves

• Carry the blood to the heart • Smallest veins = venules • Thin walls • Large veins bigger than

thumb (vena cavae) • Blood low in oxygen

– Except in pulmonary veins

• Flows under low pressure (lowest in Vena Cava furthest from left. Ventricle)

• Contain valves in the lumen

Capillaries • Thin and fragile

• One cell thin –perfect for diffusion

• exchange of oxygen and carbon dioxide takes place through the thin capillary wall.

Systemic Arterial System

Major Arteries of the Trunk

Veins

• Venules – Very small

• Medium-sized veins

• Large veins

• contain the same 3 layers as arteries – Walls are much thinner –

under less pressure than arteries

Veins with Valves

• Some veins contain valves – prevent blood from flowing backwards

Systemic Venous System

Chapter 7 – Transport in Plants

Transport in plants

• Water and mineral nutrients must be absorbed by the roots and transported throughout the plant

• Sugars must be transported from site of production, throughout the plant, and stored

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 36.7

http://extension.oregonstate.edu/mg/botany/images/fig3-big.gif

40

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

CO2 and light

H2O

O2

H2O and minerals

H2O CO2

Stoma

O2

H2O

H2O

• Water exits through stomata • Photosynthesis produces carbohydrates, which travel in phloem

• Water goes up xylem • Carbohydrates and water go up and down phloem

Carbohydrates

Carbohydrates • Water and minerals enter through roots

H2O and minerals

Xylem Phloem

Cellular transport mechanisms

Osmotic potential, solutes, and water movement

Water movement in plants

• Movement from high Ψcell to low Ψcell

• Occurs in the xylem

• Involves adhesion, cohesion, and pressure

Ψp - Pressure potential (turgor)

Low Ψp High Ψp

Xylem-hollow tubular cells that transport water and minerals

• How do plants get nutrients and water up xylem?

Transport in plants

1. Water molecules sticks to walls of xylem (adhesion)

and to each other (cohesion)

2. Water moves through xylem in column of cells 3. Air on leaf surfaces causes water to evaporate, creating a ‘pull’ on the water column (tension-cohesion theory)

• Osmotic pressure of air is greater than osmotic pressure within leaves

• Process of evaporative water loss in plants is called transpiration

Tension-cohesion theory explains xylem transport

• Water is drawn up the plant by transpiration of water from stomata

Adhesion and cohesion

A water potential gradient creates tension

Water transport

• Transpiration

Transport in plants

– 90% of water ‘absorbed’ by roots lost through transpiration in leaves

• Transpiration through stomata, pores in epidermis of leaves

• Transpiration rate regulated by two guard cells surrounding each stoma (or stomate)

Importance of stomata

• Regulate transpiration rate

– Controls rate of water uptake

• Water required for photosynthesis

• Water required to maintain turgor pressure

• Influences nutrient uptake

• Regulate gas exchange

– CO2 required for photosynthesis

Turgid guard cells open stomata

54

The Rate of Transpiration

• Over 90% of the water taken in by the plant’s roots is ultimately lost to the atmosphere

• At the same time photosynthesis requires a CO2 supply from the atmosphere

• Closing the stomata can control water loss on a short-term basis

• However, the stomata must be open at least part of the time to allow CO2 entry

55

The Rate of Transpiration

Guard cells have thicker cell walls on the inside and thinner cell walls elsewhere

-This allows them to bulge and bow outward when they become turgid

-Causing the stomata to open

Turgor in guard cells results from the active uptake of potassium (K+), chloride (Cl–), and malate

56

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Slightly inflated balloon

Tied end

Add turgor pressure (air)

Add thickened inner walls (overlapping duct tape)

“Stoma”

57

Closed stoma: flaccid guard cells

Open stoma: turgid guard cells

K+ Cl– Malate2–

H2O

H2O H2O Vacuole filled with water

Little water in vacuole

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

• When transpiration exceeds delivery of water by xylem, (soil begins to dry out) leaves begin to wilt as cells lose turgor pressure.

• Guard cells control diameter of stoma by changing shape, widening or narrowing gap between 2 cells.

Guard cells & osmotic potential

Transpiration & photosynthesis

Transport in plants

• Water and mineral nutrients are absorbed by the roots and transported throughout the plant by tension-cohesion

• Sugars are transported from site of production (source), throughout the plant, and stored (sinks) by pressure-flow

63

Phloem- tubelike cells that carry organic nutrients

Pressure-flow theory is a model describing the movement of carbohydrates in phloem

-Dissolved carbohydrates flow from a source and are released in sink

-Sources include photosynthetic tissues

-Sinks include growing root and stem tips

as well as developing fruits

64

Phloem Transport

A t the source

-Active transport of sugars into the phloem causes a reduction in water potential

-Then water follows into the phloem, turgor pressure drives the contents to the sink

- At the sink, sugar is actively transported into cells

-Then water diffuses back into the xylem to be reused or lost through transpiration

66

Shoot tip: sink

Leaf: source

Root: sink

Active transport of sucrose out of phloem, into growth areas (sinks)

Passive transport of sucrose and water

Active transport of sucrose out of phloem, into growth areas (sinks)

Xylem

Phloem

Water molecule

Some water passively follows sucrose into phloem

Active transport of sucrose into phloem Photosynthesizing cell

Sucrose molecule

water (passive transport)

sucrose (passive transport)

sucrose (active transport)

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67

Air

P

lan

t

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0 –0.5 –1.0 –100

w Water potential (MPa)

The water film that coats mesophyll cell walls evaporates. Rippled cell surfaces result in higher rate of transpiration than smooth cell surfaces.

Smooth surface

Rippled surface

Cohesion by hydrogen bonding between water molecules

Adhesion due to polarity of water molecules

Water exits plant through stomata.

Water moves up plant through xylem.

Water enters plant through roots.

Soil

Proton pumps contribute to the w gradient that determines the directional flow of water.

Cytosol

Soil

H+

Mineral ions

Water

Proton pump

H2O

H2O

Soil

Air

P

lan

t

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

0 –0.5 –1.0 –100

w Water potential (MPa)

The water film that coats mesophyll cell walls evaporates. Rippled cell surfaces result in higher rate of transpiration than smooth cell surfaces.

Smooth surface

Rippled surface

Cohesion by hydrogen bonding between water molecules

Adhesion due to polarity of water molecules

Water exits plant through stomata.

Water moves up plant through xylem.

Water enters plant through roots.

Soil

Proton pumps contribute to the w gradient that determines the directional flow of water.

Cytosol

Soil

H+

Mineral ions

Water

Proton pump

H2O

H2O

Soil

Guttation

• Root pressure causes guttation - appearance of water droplets (seen in morning on tips of grass blades)

• Roots accumulate water during night, transpiration is low, water enters leaf at faster rate.

Water transport

Sugar transport