transport systemss (READ OVER BEFORE PAPER 1 )

Question 1

lymph system

Answer 1

tissue fluid directed into lymph system if it doesnt reenter blood

..lymph system drains excess tissue fluid out of tissues and returns it to blood system in subclavian vein in chest .

. fluid in lymphatic system - lymph , similari n compositin to tissue fluid

contaisn more lymphocytes- produced by lymph nodes

Question 2

flow of blood through the heart

Answer 2

deox blood flows from body through vena cava into right atrium .

oxygenate blood flows from lung through pulmonary vein into left atrium

.from atria, blood flows down through atrioventricular valves into ventriels .

tedinpus chords prevents valves from turning inside out
when ventricles contract

wall of muscle= septum- seperates ventricles from each other – ensures oxygenated blood and deox blood is kept seperate

deox blood leaving right vntricel flow through pulmonary artery and itno lungs to be xgenated.
oxygenated blood leaving left ventricle flowsi nto the aorta which carries bload to artreies to supply body parts

semilunar vavles prevetn blood form reutrning to heart as ventricles relax !

Question 3

cardiact cycle

Answer 3

ventricular systole= both ventricles contract = starts at base of heart - blood pushed upwards towards arteries

.diastole- muscular walls of all 4 chambrs relax- elastic recpils - causes chambers to increase in volume- allows blood flow from veins

atrial systole both atria contract. muscle in wall thin so small increase in pressure created by this contraction
. pushes blodo into ventricle - stretches walls and ensures they are full of blood

.

Question 4

the action of the valves

Answer 4

after systole - ventricular pressure drops below pressure in atria

.blood in atria pushes atrioventricular valves open

.blood flows thorugh atria nad into ventricels and presusre in both rise slwoly as blood fills

.valves remain open while atria contract - close when atria relax ( closure caused by swiriling of blood around the valves when ventricle full

.as ventricels contract, pressure of blood in ventricle rises

when pressure rises above atra , blood moves upwards

.movememnt fills valves pockets and keeps them closed

.tedinous cords attached to valves prevent them from turning insuide out

.prevents blood flowing back into the atria

Question 5

semiulunar valves

Answer 5

before ventricular contraction- pressure in major arteries higher than pressure in ventricles- means smeilunar valves closed

.ventricular systole - riase blood pressure in ventrices

.once pressure in ventricels rises aboce pressure in major arteries , semilunar valves pushed open

. blood under high pressure so forced put of the ventricles in powerful spurt

. once ventricle walls finsih contracting, heart muscle relaxes

.elastic tissue in walls of ventricles recoil

. stretches muscle out again and returns ventricle to original size

.causes pressure in ventricles to drop quickly. as it drops below pressure in major arteries ,blood flows back towards venctricles

.semilunar valves pushed closed by blood colelcting in valve pockets

.prevents blood from returning to ventricles

.pressure created when left semilunar closes is the “pulse” that we feel on our wrist/ neck