B3.2 Animal+Plant Transport

blood vessels

arteries

veins

capillaries

arteries , vein , capillaries - exchange of blood

arteries: away

Veins: to

Capillaries: site of exchange

adaptations of capliiaries

1. short diameter - one cell thick , allow passage of one single RBC at a time

2. capillary wall - single layer of cell - minimize diffusion distance

3. surrounded by basement membrane- permeable

Capilaries structure may vary depend on location and function

1. continous : connected with endothelial cells - limit permeability of large molecules

2. fenestrated : pores . in tissue specialised for absorption eg. kidney

3. sinusoidal : imcomplete basemnet membrane - open spaces between cells , permeable to large molecues . eg. liver

arteries&veins

arteries:

• narrow lumen : high pressure blood

• thick muscle fibre : prevent rupture

• thick elastic fibre : pulse.

  • elastc fibre allwos arteries to stretch - presure exerted on the artieral walls - elastic recoil - pushes blood forward. Contraction of artieries = One pulse

• vein

• thick lumen : maintain low pressure blood

• valve : prevent backflow

• thin layer of muscles and elastic fibres , srrounded by skeletal muscle.

  • skeletal muscle contract, squeeze vein , opens valve - blood move forward. Relaxes, valve close - blood trapped in vein

measurement of heart rate

• radial pulse in wrisk

• carotid pulse in neck

conorary occultion

artherosclerosis is the hardening and narrowing of artieries due to cholesterol

arteromos develop in the arteries - reduce diameter of lumen

higher pressure exerted on the walls - leading to damage

repaired by inelastic fibrious tissue - reduce elasticity

damaged area forms plaque - plaque ruptures - trigger blood clotting, forming thrombus - restrict blood flow, dislodged - block entire smaller artieriole

consequence

• myocardial infaraction ( heart attack)

  • myocardial tissue requires oxygen and nutrients via conorary artieries to function

  • conorary artery blocked - result into heart attack

Treatment

• bypass surgery

vascular bundle

• xylem & phloem

• water+ minerals

• carbon compounds - sucrose+amino acid+ hormones

xylem

facilitate the movement of water

• tube make up of strong dead cells , hollow - unimpeded flow of water

  • water movement : passive , one direction( roots to leaves)

• pits : water transfer between cells

• strengthened with lignin in spirals -- withstand low pressure without collapsing 

leaves - draw and label and function 

• photosynthesis, light absorption , gas exchange

waxy cuticle - hydrophobic, prevent water loss

upper epidermis

palisade mesophyill - chloroplast - photosynthesis

spongy mesophyll - lots of air spaces - gas exchange

vascular bundle

lower epidermis

stoma + guard cells - open channel for gas

stem - draw and label and function 

• support, elevate leaves for seed dispersal and photosynthesis

xylem - transport of water from roots - leaves 

cambium - production of xylem&phloem tissue 

phloem - transport of sugar from source to sink 

epidermis - protection and waterproof 

cortex - support and photosynthesis 

pith - packing tissue ( bulking out the stem) 

root - draw label and function

(xylem - cambium - phloem - endodermis - cortex - epidermis)

• epidermis: has root hair to increase water and mineral absorption

• cortex: cells loosely packed - enable movement of water

• endodermis: layers of cell water pass through reach xylem

Transpiration

water vapour lost via stomata

facilitates

• temperature regulation

• absorption of water and minerals from soil

loss of water by transpiration from cell walls in leaf cells

causes water to be drawn out of xylem vessels and through cell walls by capillary action, generating tension (negative pressure potentials).

It is this tension that draws water up in the xylem.

Cohesion ensures a continuous column of water

measure rate of transpiration

potometer