transport in animals

do fish have a single or double circulatory system

single.

• the heart pumps blood to the gills to pick up oxygen

• blood flows directly from the gills to the rest of body to deliver oxygen

how does the double circulatory system in mammals occur

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

• the left side of the heart pumps oxygenated blood to the rest of the body.

what group of animal have closed circulatory systems

vertebrates

what happens in a closed circulatory system

• blood is contained in vessels

• arteries generally distribute oxygenated blood

• veins generally distribute deoxygenated blood to the heart

what group of animals have open circulatory systems

invertebrates like insects

what happens in an open circulatory system

• blood flows freely through the body cavity

• blood returns to the heart through valves

• blood odesn’t just transport oxygen

what is the difference between the systemic and pulmonary circulation systems

in systemic circulation: (heart-body-heart)

1. oxygenated blood is pumped out of heart via the aorta to the body tissues

2. deoxygenated ir returned to the heart via the vena cava

in pulmonary circulation: (heart-lungs-heart)

1. deoxygenated blood is pumped out of the heart via the pulmonary artery to the lungs

2. oxygenated blood is returned to the heart via the pulmonary vein

what is the function of arteries

carry blood away from the heart at high pressure

what is the function of arterioles

carry blood from arteries into capillaries

what is the function of capillaries

site of diffusion between blood and body tissues

what is the function of venules

carry blood from capillaries to veins

what is the function of veins

return deoxygenated blood to the heart at low pressure

what are the adaptations of arteries for carrying blood at high pressure

1. collagen- provides strength to prevent the vessel from bursting and to maintain vessel shape

2. elastic fibres- contain elastin that lets them stretch and recoil to minimise changes in pressure

3. thick smooth muscle layer- contracts/ relaxes to constrict/dilate the lumen and control blood flow

why do the walls of arterioles have more smooth muscle and less elastin than arteries

they do not need to withstand such high pressures

how do arteries and arterioles vasoconstrict

smooth muscle contracts, constricting the blood vessel and reducing blood flow

how do arteries and arterioles vasodilate

smooth muscle relaxes, dilating the blood vessel and increasing blood flow

what are the adaptations of capillaries

1. lumen is very narrow- allows red blood cells to be close to body cells

2. walls are thin- substances can be exchanged across a short diffusion distance

3. highly branched- provides a large surface area for diffusion

what are the adaptations of veins for carrying blood at low pressure

1. collagen- provides strength to prevent the vessel from bursting and maintain vessel shape

2. little smooth muscle and elastic fibre- not much is needed due to low blood pressure, and thinner walls allow veins to be easily compressed, aiding the flow of blood

3. valves- prevent backflow of blood when veins are squeezed by surrounding skeletal muscle

do venules contain valves

yes, however venules are smaller than veins

what is the composition of blood

• plasma- mostly water, transports substances in solution

• red blood cells- carry oxygen

• white blood cells- immune cells

• platelets- involved in clotting

where is tssue fluid located

is fills spaces between cells

what are the differences in composition of tissue fluid and plasma

• tissue fluid has no red blood cells

• tissue fluid has fewer proteins

• tissue fluid has fewer white blood cells

at the arteriole end of capillaries, there is a high hydrostatic pressure in the capillaries due to the force of the heart pumping. What effect does this have

fluid is forced out of capillaries, forming tissue fluid surrounding cells

at the venule end of capillaries, what is responsible for exerting a high oncotic pressure

proteins in the blood

at the venule end of capillaries, what does a high oncotic pressure in the blood and a low water potential in the capillaries cause

since the water potential is higher in the tissue fluid, some tissue fluid moves back into the capillaries by osmosis

what is some difference in the composition of lymph and tissue fluid

• lymph has less oxygen and nutrients

• lymph has more fatty acids

• lymph has more white blood cells (lymphocytes)

simply, what is lymph formed from

tissue fluid

how is lymph formed

1. some tissue fluid doesn’t re-enter the capillaries

2. instead, it drains into lymph vessels, forming lymph

how is lymph transported around the body

1. it is transported through lymph vessels by muscle contractions

2. it is passed through lymph nodes to filter pathogens

3. it is eventually returned to the blood

how is oxygen transported from the lungs to body cells

1. in the capillaries in the lungs, oxygen binds to iron in haem groups forming oxyhaemoglobin

2. each haemoglobin molecules can carry 4 oxygen molecules, one per haem group

3. oxyhaemoglobin can be transported via blood to respiring body tissues

4. at body cells, oxygen dissociates from haemoglobin

how does a high partial pressure affect haemoglobin saturation with oxygen

at high partial pressure, haemoglobin has a high affinity for oxygen and binds with it.

where in the body is there a high partial pressure and haemoglobin has a high affinity for oxygen

in the lungs

how does a lower partial pressure affect haemoglobin saturation with oxygen

haemoglobin has a low affinity for oxygen and releases it.

where in the body is there a low partial pressure and haemoglobin has a low affinity for oxygen

respiring body cells

in what instances does haemoglobin change shape during cooperative oxygen binding

1. when haemoglobin binds with oxygen, it changes shape so that it is easier to bind to other oxygen molecules

2. when haemoglobin is mostly saturated with oxygen, it changes shape so that it is harder for more oxygen to bind

why does fetal haemoglobin have a higher affinity than adult haemoglobin

• it allows oxygen to dissociate from the mother’s haemoglobin so that it can bind with haemoglobin in the fetal blood.

• it ensures that the fetus has enough oxygen to survive while it develops

describe the Bohr effect

haemoglobin has a lower affinity for oxygen at higher partial pressures of carbon dioxide.

more indepthly

• higher p(CO2) at respiring tissues causes haemoglobin to release oxygen

• this means the oxygen saturation of haemoglobin is lower for a given p(O2) when p(CO2) is higher

why is the Bohr effect needed

because actively respiring tissues that produce carbon dioxide require a lot of oxygen from the blood. The Bohr effect shifts the oxygen dissociation curve to the right, causing oxygen to dissociate more readily

why is it useful for CO2 to be converted into another form in the blood

because it maintains a steep diffusion gradient between respiring tissues and the blood, which need to get rid of CO2.

what are some alternate ways that CO2 can be transported via the blood

1. dissolved in plasma

2. some CO2 enters red blood cells, and is transported bound to haemoglobin as carbaminohaemoglobin

how is CO2 converted to hydrogen carbonate ions

1. CO2 reacts with water to form carbonic acid (H2CO3), catalysed by the enzyme carbonic anhydrase

2. H2CO3 dissociates to H+ and HCO3-

how is the Bohr effect caused

1. once H2CO3 dissociates to form H+ and HCO3-, H+ binds to haemoglobin forming haemoglobonic acid, causing haemoglobin to release oxygen

2. this means that at high p(CO2), haemoglobin releases oxygen so it can diffuse into respiring tissues.

how is the chloride shift caused

1. HCO3- ions leave red blood cells and are transported via plasma, while chloride ions enter red blood cells

2. this is called the chloride shift, and it maintains the charge balance by preventing excessive positive charge in red blood cells

what is the enzyme called that catalyses the reaction between water and CO2

carbonic anhydrase

how is pH in the blood stopped from becoming too acidic

H+ ions bind to haemoglobin forming haemoblobonic acid

at areas in the body with low p(CO2), what happens to HCO3- and H+ ions

in the lungs for example, low p(CO2) causes HCO3- and H+ to reform CO2

CO2 diffuses out of the body during expiration

what are the differences between the atria and the ventricles

1. atria- the top chambers of the heart that collect blood from blood vessels (veins)

2. ventricles- the bottom chambers of the heart that pump blood into blood vessels (arteries)

why does the heart need two seperate pumping mechanisms (one on each side of the heart)

• blood pressure drops in the lungs as it flows through the capillaries

• a single pump would slow the blood flow to the body cells

• two pumps increases the pressure before the blood circulates

what is the function of the septum

it seperates the two sides of the heart, preventing oxygenated and deoxygenated blood from mixing

where are the two atrioventricular valves located

1. the tricuspid valve is located between RA and RV

2. the bicuspid valve is located between LA and LV

   (they prevent the backflow of blood into the artia)

where are the semi-lunar valves located

• between the ventricles and the pulmonary artery and the aorta (they prevent the backflow of blood into the ventricles)

why are ventricle walls thicker than atria walls

• the atria only need enough pressure to pump blood a short distance into the ventricles

• whereas, the ventricles need a lot of pressure to pump blood a long distance out of the heart to other organs

what ventricle wall is thicker, and why

the left ventricle wall is thicker than the right because…

• the right ventricle only needs enough pressure to pump deoxygenated blood a short ditance to the lungs

• whereas, the left ventricle needs a lot of pressure to pump oxygenated blood to more distant ograns in the body

name the three stages of the cardiac cycle

1. atrial systole

2. ventricular systole

3. diastole

what happens during Stage 1 of the cardiac cycle, atrial systole

• the ventricles relax, and the atria contract

• this increases atrial pressure

• the atrioventricular valves open

• blood flows into the ventricles

when happens during stage 2 of the cardiac cycle, ventricular systole

• the vetricles contract, and the atria relax

• ventricular pressure increases

• the semi-lunar valves open, and the atrioventricular valves close

• blood flow into the arteries

what heppens during stage 3 of the cardiac cycle, diastole

• the ventricles and atria relax

• the semi-lunar valves close

• blood flows passively into the atria

what does cardiac muscle being myogenic mean

it means that the contraction of cardiac muscle initiates within the heart itself

in what order does the electrical wave travel through the heart

1. sinoatrial node (SAN)- intiates the heart beat by stimulating the atria to contract

2. layer of collagen fibres prevent direct electrical flow from the atria to the ventricles

3. atrioventricular node (AVN)- picks up the electrical activity from the SAN and imposes a slight delay

4. Bundle of His- receives electrical activity from the AVN and conducts a wave of excitation to the base of the heart (apex)

5. Purkyne Fibres- these branch off the bundle of His, causing the right and left ventricles to contract from the bottom upwards

what wave represents atrial systole

P wave

what wave reresents ventricular systole

QRS wave

what wave represents diastole

T wave

define tachycardia

an abnormally rapid heart rate

define bradychardia

an abnormally slow heart rate

define ectopic heartbeats

extra heartbeats out of the normal rythmn

define atrial fibrillation

the abnormally rapid and ineffective contraction of the atria