Bio - Gas Exchange

characteristics of gas exchange surfaces

thin, permeable to gases, large surface area to volume ration, moist

concentration gradient in gas exchange

allows for simple diffusion

adaptations of the lungs

branching bronchioles ending in alveoli, large surface area, capillary beds, short diffusion distance, moist surface

ventilation

moving air in and out of lungs

inhalation

diaphragm and external intercoastal muscles contract, abdominal and interior intercoastal muscles relax, volume increases and pressure decreases

exhalation

diaphragm and external intercoastal muscles relax, abdominal and interior intercoastal muscles contract, volume decreases, pressure increases

ventilation rate

inhalation/exhalation per minute

tidal volume

volume of air inhaled/exhaled per breath

inspiratory reserve volume

amount of air that can be inhaled after a breath

expiratory reserve volume

amount of air that can be exhaled after a breath

vital capacity

maximum amount of air the lungs can hold

spirometry

detects changes in ventilation by volume or speed

adaptations in leaves for gas exchange

broad, flat, and thin surface, epidermis, palisade and spongey mesophyll layer, vascularized leaves

epidermis

thin layer covered in waxy cuticle that prevents water loss

stomata

stomatal pores facilitate water and gas exchange

guard cells

control opening and closing of stomata

palisade mesophyll layer

tightly packed with chloroplasts to optimize photosynthesis

spongy mesophyll layer

loosely packed with intercellular air space to maximize gas exchange

parts of a root

epidermis, cortex, xylem and phloem

root epidermis

root hairs maximize surface area for water and mineral absorption

root cortex

facilitates water movement between loosely packed cells and stores starch

vascular tissue in roots

transport of materials to other parts of plants; surrounded by casparian strip

casparian strip

a modified cell wall that is impermeable to water and controls water movement

parts of a stem

epidermis, cortex, pith, xylem and phloem

stem epidermis

waterproofs and protects stem

stem cortex and pith

assists in nutrient storage and lateral growth

stem vascular tissue

bundles around outer edge, resist stem compression and bending