Transport in animals

state the 4 types of circulatory systems?

• single

• double

• open

• closed

how does blood pass within a single circulatory system?

• blood only passes through the heart once for each complete circuit of the body

how does blood pass within a double circulatory system?

• blood passes through the heart twice for each complete circuit of the body

how does the heart pump blood in fish?

the heart pumps blood to the gills to pick up oxygen then to the rest of the body to deliver oxygen in a single circuit

how does the heart pump blood in mammals?

• the right side of the heart pumps blood to the lungs to pick up oxygen

• it then travels to the left side of the heart which pumps to the rest of the body

• when blood returns to the heart it enters the right side again

state an advantage of the mammalian double circulatory system?

• blood travels more faster so oxygen is delivered to the tissues more quickly at a higher pressure

what circulatory system do vertebrates have?

• a closed circulatory system

define the closed circulatory system?

• the blood is enclosed within blood vessels

• the heart pumps blood into arteries

• these branch out into millions of capillaries

• substances like oxygen and glucose diffuse from the blood in the capillaries in the body cells

• veins take the blood back to the heart

what type of circulatory system do invertebrates have?

• an open circulatory system- blood isnt enclosed in blood vessels all the time therefore flows freely through the body cavity

how does blood flow in an open circulatory system?

• the blood flows freely from the heart into the body cavity and comes into direct contact with the cells

• exchange of substances takes place before returning to the heart through open ended vessels

what is the function of arteries?

• carry blood away from the heart to the rest of the body

what is the structure of arteries?

• thick muscular elastic walls which stretch and recoil as the heart beats to help maintain high pressure

which arteries do not carry oxygenated blood?

pulmonary arteries

what structures do arteries branch into?

arterioles

state the function of arterioles?

smooth blood vessels which distribute blood from an artery to a capillary

structure of arterioles?

• walls containing rings of smooth muscle allowing them to expand or contract controlling blood flowing into tissues

what structures do arterioles branch into?

• capillaries

which is the smallest blood vessel?

capillaries

state how capillaries are adapted for efficient diffusion?

their walls are one cell thick

what structures do capillaries branch into?

venules

what do venules join together to form?

veins

function of veins?

• carry blood towards the heart at low pressure

• have valves to prevent backflow

do veins carry oxygenated or deoxygenated blood?

deoxygenated blood as the oxygen has been used up by body cells

which vein carries oxygenated blood?

pulmonary vein

which blood vessel has the largest lumen?

the veins

which blood vessel has the most muscular walls?

arteries

define tissue fluid?

the fluid that surrounds cells in tissues

what is tissue fluid made from?

substances which leave the blood plasma

why dont tissue fluids contain red blood cells or big proteins?

because they are too large to be pushed through capillary walls

define capillary bed?

the network of capillaries in an area of tissue

define hydrostatic pressure?

the pressure created by a fluid pushing against the container that its within

define oncotic pressure?

the pressure created by osmotic effects of the solutes in a solution

define lymphatic system?

drains surplus tissue fluid away from the cells

how is tissue fluid formed?

• high blood pressure causes hydrostatic pressure forces fluid out filtered by holes in the capillary

• large proteins remain in the capillary generate opposing force- oncotic pressure

how does tissue fluid return?

• low water potential in capillary due to plasma proteins

• water enters capillary by osmosis due to oncotic pressure

• lymphatic system drains surplus fluid

what is tissue fluid formed from?

blood

what is lymph formed from?

tissue fluid

where does the right side of the heart pump blood to, oxygenated or deoxygenated?

pumps deoxygenated blood to the lungs

where does the left side of the heart pump blood to, oxygenated or deoxygenated?

pumps oxygenated blood to the rest of the body

what do the atrovetricula valves link together?

link the atria to the ventricles

what do the semi lunar valves link together?

link the ventricles to the pulmonary artery and aorta

what do ventricles prevent?

the backflow of blood

define systole?

contracting

define diastole?

relaxing

define myogenic?

can contract and relax without receiving signals from nerves

define the SAN?

sino atrial node

where is the sino atrial node located?

in the wall of the right atrium

state the function of the SAN?

it sets the rhythm of the heart beat by sending out regular waves of electrical activity to the atrial walls

how does the SAN affect the right and left atrium after sending waves?

causes the right and left atria to contract at the same time

what does a band of non conducting collagen prevent?

the waves of electrical activity from being passed from the atria to the ventricles

where are the electrical waves of activity transferred instead?

transferred from the SAN to the AVN

what is the AVN responsible for?

for passing the waves of electrical activity on to the bundle of His

define the bundle of His?

a group of muscle fibres responsible for conducting the waves of electrical activity to the finer muscle fibres in the right and left ventricle walls called purkyne tissue

what does the purkyne tissue carry?

carries the waves of electrical activity into the muscular walls of the right and left ventricles causing them to contract causing them to simultaneously contract from the bottom to the top

what does the term ECG stand for?

electrocardiograph

what is the name of the trace produced by an electrocardiogtraph?

an electrocardiogram

what does the P wave represent?

contraction/ depolarization of the atria

what is the main peak of the heartbeat called?

the QRS

what does the QRS represent?

ventricular contraction/ depolarisation

what does the T wave represent?

ventricular relaxation/ repolarisation

what does the height of the wave indicate?

how much electrical charge is passing through the heart

define tachycardia?

fast heartbeat, 120bpm

define bradycardia?

slow heartbeat <60 bpm

when can an ectopic heartbeat occur?

when the atria or ventricle has had an extra contraction

define ventricular fibrillation?

a really irregular heartbeat

what do red blood cells contain?

haemoglobin

define haemoglobin?

a large protein with a quaternary structure

what element gives haemoglobin its red colour?

iron

define affinity for oxygen?

the tendency to combine with oxygen

does haemoglobin have a high or low oxygen affinity?

high oxygen affinity

how many oxygen molecules can each haemoglobin molecule carry?

4 oxygen molecules

in the lungs, what is formed when oxygen joins the iron in haemoglobin?

oxyhaemoglobin

what is the unit of partial pressure?

pO2

what is partial pressure a measure of?

oxygen concentration

what does the greater the concentration of dissolved oxygen in cells result in?

a higher partial pressure

what is the unit for partial pressure of carbon dioxide?

pCO2

what is the partial pressure of carbon dioxide a measure of?

the concentration of carbon dioxide in a cell

what does haemoglobin’s affinity for oxygen vary depending on?

depending on the partial pressure of oxygen

what happens at high pO2 ?

oxygen loads onto haemoglobin to form oxyhaemoglobin

what happens at low pO2?

oxyhaemoglobin unloads its oxygen

do the alveoli have high or low pO2?

high pO2

when cells respire does this increase or decrease pO2?

decreases pO2

where do red blood cells deliver oxyhaemoglobin?

to respiring tissues where it unloads its oxygen, the haemoglobin then returns to the lungs to pick up more oxygen

what does an oxygen dissociation curve show?

how saturated the haemoglobin is with oxygen at any given partial pressure

what happens where pO2 is high?

• haemoglobin has a high affinity for oxygen so has a high saturation of oxygen

what happens where pO2 is low?

• haemoglobin has low affinity for oxygen

• releases oxygen rather than combining with it

• has low oxygen saturation

what does 100% saturation mean?

every haemoglobin molecule is carrying the maximum of 4 molecules of oxygen

what does 0% saturation mean?

none of the haemoglobin molecules are carrying any oxygen

how do adult and fetal haemoglobin differ?

fetal haemoglobin has a higher affinity for oxygen

why does the fetus have higher oxygen affinity in its haemoglobin?

in order to survive

what would happen if the fetal haemoglobin had the same oxygen affinity as adult haemoglobin?

• its blood wouldnt be saturated enough

what does CO2 react with water to form?

carbonic acid

which enzyme is carbonic acid catalysed by?

carbonic anhydrase

what does carbonic anhydrase dissociate to form?

H+ ions and HCO3- ions

what does an increase in H+ ions cause, forming what acid?

causes oxyhaemoglobin to unload its oxygen so that haemoglobin can take up the H+ ions forming haemoglobinic acid

what do the HCO3- ions diffuse out of and where are they transported?

diffuse out of red blood cells and are transported in the blood plasma

which ions diffuse into the red blood cells to compensate for HCO30 loss?

Cl- ions

what does the chloride shift maintain?

the balance of charge between the red blood cell and the plasma

when blood reaches the lungs and there is low pCO2, which ions recombine into CO2?

• HCO3- and H+ ions

where does CO2 then diffuse to be breathed out?

diffuses into tthe alveoli