Mass Transport (Animals)

give the pathway a red blood cell taken when travelling in the human circulatory system from a kidney to the lungs

1. renal vein

2. vena cava to right atrium

3. right ventricle to pulmonary artery

define mass transport

the bulk movement of gases or liquids in one direction

why is mass transport important in animals (3)

• helps bring substances quickly from one exchange site to another

• help maintain the diffusion gradients at exchange sites between cells and their fluid surroundings

• ensures effective cell activity by keeping the immediate fluid environment of cells within a suitable metabolic range

draw and label the circulatory system in animals (8)

explain how the structure of the RBC makes them efficient for carrying oxygen (4)

• have haemoglobin which oxygen binds to

• are biconcave so give high SA:V ratio

• do not contain nucleus so provide more space inside the cell for haemoglobin so that they can transport as much oxygen as possible

• existence of Fe2+ in the haemoglobin allows oxygen to reversibly bind to it

explain co operative binding in hemoglobin

• binding of the first oxygen molecule results in a confrontational change in the structure of the hemoglobin

• making it easier for each successive oxygen molecule to bind

define affinity of oxygen

the ease with which each haemoglobin binds and dissociates with oxygen

explain the shape of the curve on an oxygen dissociation graph (7)

• due to shape of haemoglobin molecule, it is difficult for the first oxygen molecule to bind to it

• therefore the binding for the first oxygen occurs slowly

• therefore there is a shallow curve at the bottom left

• however after the first oxygen, it is easier for the other oxygens to bind due to cooperative binding

• explaining the steeper part of the curve in the middle of the graph

• it takes longer for the fourth oxygen molecule to bind due to the shortage of remaining binding sites

• explaining the levelling off

define Bohr shift (1)

changes in the oxygen dissociation curve as a result of CO2 levels

explain why the Bohr shift happens (4)

• when partial pressure of CO2 is high, haemoglobin affinity for oxygen is reduced

• because CO2 lowers the pH of the blood by combining with water to form carbonic acid

• which dissociates into hydrogen and hydrogen carbonate ions

• meaning that at any partial pressure of oxygen, the percentage saturation of haemoglobin is lower at higher levels of CO2

draw an oxygen dissociation curve and label it

draw an oxygen dissociation curve and a new one with higher levels of CO2

define cardiac output

describes the volume of blood that is pumped by the heart per unit of time

how to recognise stroke volume on a graph

amount between highest point on curve and lowest point on curve

why are haemoglobins shapes in different animals

the partial pressure of oxygen in the air is lower at higher altitudes so species in those altitudes have haemoglobins that are adapted to these changes

draw an oxygen dissociation curve and a new one with higher altitude

define as closed circulatory system

blood is pumped around the body and is always contained within a network of blood vessels

define open circulatory system

blood is contained within blood vessels but is pumped directly into body cavities

define closed double circulatory system (3)

• in one complete circuit of the body, blood passes through the heart twice

• the right side of the heart pumps deoxygenated blood to the lungs for gas exchange

• blood then returns to left side of heart so that oxygenated blood can be pumped efficiently

define pulmonary circulatory system

the right side of the heart pumps deoxygenated blood to the lungs for gas exchange

define systemic circulatory system

blood then returns to left side of heart so that oxygenated blood can be pumped efficiently

what is the function of the heart

• muscle which pumps blood

what is the function of the arteries

blood vessels which carry blood away from the heart

what is the function of arterioles

small arteries which branch from larger arteries and connect to capillaries

what is the function of capillaries

pass directly past cells and tissues and perform gas exchange and exchange of substances

what is the function of venules

small veins which join capillaries to larger veins

what is the function of veins

blood vessels which carry blood towards the heart

name the main blood vessels (7)

• pulmonary artery

• pulmonary vein

• coronary arteries

• aorta

• vena cava

• renal artery

• renal vein

what is the function of pulmonary artery

carries deoxygenated blood away from heart, towards the lungs

what is the function of pulmonary vein

carries oxygenated blood away from the lungs towards the heart

what is the function of coronary arteries

supply the heart with oxygenated blood

what is the function of aorta

carries oxygenated blood out of the heart and to the rest of the body

what is the function of vena cava

carries deoxygenated blood into the heart

what is the function of renal artery

supplies the kidneys with oxygenated blood

what is the function of renal vein

carries deoxygenated blood away from the kidneys, towards the heart

draw and label the heart (10)

explain how the valves open and close (2)

• open when the pressure of blood behind them is greater than the pressure in front of them

• close when the pressure of blood in front of them is greater than the pressure behind them

define interatrial septum

portion of the septum which separates the left and right atria

define the interventricular septum

separates the left and right ventricles

define atrioventricular valve

separates the right atrium and right ventricle

define bicuspid valve

separates the left atrium and left ventricle

what are the two vessels bringing blood to the heart (2)

• vena cava

• pulmonary vein

what are the two vessels taking blood away from the heart (2)

• artery

• aorta

what is the function of coronary arteries

supply the cardiac muscle with deoxygenated blood , nutrients and remove waste products

explain why the atria walls and ventricle walls have different structures (4)

• atria walls are thinner than ventricle walls as they do not need to generate as much pressure

• but enough to force blood down into the ventricles through the AV valve

• ventricle walls are thicker and more muscular

• and they need increases pressure to push the blood out of the heart through the semilunar valves

explain the different in structure of left and right ventricle (4)

• muscle of left ventricle is significantly thicker than right ventricle

• blood pumped from right ventricle travels to lungs only whereas

• blood pumped from left ventricle travels to rest of body

• therefore blood leaving the right ventricle travels less distance than that leaving the left ventricle

define the term cardiac cycle

the series of events that take place in one heart beat

what is the term which describes the contraction of the heart

systole

what is the term which describes the relaxation of the heart

diastole

explain the volume and pressure changes in the cardiac cycle (3)

• contraction of the heart muscle causes a decrease in volume

• which increases again when the muscle relaxes

• volume decrease leads to pressure increase

explain the atrial systole (6)

• the walls of the atria contract

• atria volume decreases

• atria pressure increases above the ventricles

• forcing the AV valves open

• blood is forced into the ventricles which increases the ventricular pressure and chamber volume

• ventricles are relaxed at this point as ventricular systole coincides with atrial diastole

explain the ventricular systole (6)

• walls of the ventricles contract

• ventricular volume decreases

• ventricular pressure increases forcing the AV valves to close, preventing the backflow of blood

• the pressure increase in ventricles above the aorta and pulmonary artery forces the semi-lunar valves open

• so blood is forced into the arteries and out of the heart

• during this, the atria are relaxing as atrial diastole coincides with ventricular systole

explain diastole (7)

• ventricles and atria are both relaxed

• the pressure in the ventricles drops below that in the aorta and pulmonary artery

• forcing the SL valves to close

• atria continues to fill with blood as it returns to the heart via pulmonary vein and vena cava

• pressure in the atria rises above that in the ventricles forcing the AV valves open

• blood flows passively into the ventricles

• cycle begins again with atrial systole

explain atrial systole, ventricular diastole (2)

• atria contract

• pushing blood into the ventricles

explain atrial diastole, ventricular systole (3)

• atria relax

• ventricles contract

• pushing blood out of the heart

explain cardiac diastole (2)

• all chambers are relaxed

• blood flows into the heart

name 5 factors that can influence heart rate (5)

• drugs

• caffeine

• alcohol

• sex

• temperature

describe and explain the structure of arteries (7)

• walls are relatively thick

• as they must be able to withstand high pressures generated by contracting the heart

• and maintain these pressures when the heart is relaxed

• elastic fibres allow the artery wall

• to expand around the blood surging through at high pressure when heart contracts

• these fibres then recoil when the heart relaxes

• alongside a narrow lumen maintains high blood pressure

describe and explain the structure of veins (4)

• wall of vein is relatively thin as they receive blood that has passed through the capillary network

• therefore it is at a low pressure

• lumen is much larger than artery

• contain valves that prevent backflow of blood

explain the structure and function of capillaries

• have thin walls with gaps that are ‘leaky’

• allowing substances to leave the blood to reach the body’s tissues

• they can form networks called capillary beds

• which are very important exchange surfaces within circulatory system

• have small diameter lumen

• which forces the blood to travel slowly which provides more opportunity for diffusion to occur

• walls are one ednothelial cell thick to reduce the diffusion distance for O2 and CO2

how is tissue fluid formed (7)

• as blood passes through capillaries, some plasma leaks out through the gaps in the walls of the capillaries to surround the cells of the body

• when blood is at the end of the arteriole end of capillary, the hydrostatic pressure is great enough to push fluid out of the capillary

• protein remain in the blood

• the increases protein content creates a water potential between capillary and tissue fluid

• at venule end of capillary, less fluid is pushed out of the capillary as hydrostatic pressure within the capillary is reduced

• the water potential gradient remains the same at the arteriole end

• so water begins to flow back into the capillary from the tissue fluid via osmosis

how does hypertension affect tissue fluid (2)

• blood pressure is high then the pressure at the arteriole end is even greater

• this pushes more fluid out of the capillary and fluid begins to accumulate around the tissues

define oedema

build up of tissue fluid in the body

how is lymph formed (6)

• some tissue re enters the capillaries while some enters the lymph capillaries

• which have closed ends and large pores that allow large molecules to pass through

• larger molecules enter the lymphatic system

• the liquid moves along the larger vessels of this system by compression caused by body movement

• the lymph eventually re enters the bloodstream through the veins close to the heart

• any plasma proteins that have escaped from the blood are returned via lymph capillaries

what does blood plasma consist of (5)

• glucose

• amino acids

• mineral ions

• oxygen

• plasma proteins

define what is meant by cardiac cycle

the sequence of events that make up a single heartbeat

explain the cardiac cyle (5)

• contraction of the muscles in the wall of the heart reduces the volume of the heart chamber

• increasing the pressure of the blood within that chamber

• when the pressure withing a chamber exceeds the next chambers, valves are forced open and blood moves through

• then the muscle in the wall of the heart relax and recoil which increases the volume of the chamber

• decreasing the pressure so that the valves close

what are the main risk factors for coronary heart disease (5)

• genetic factors

• age and sex

• high blood pressure

• smoking

• high conc of low density lipoproteins

explain how water from tissue fluid is retuned to the circulatory system (4)

• plasma proteins remain

• creating water potential gradient

• waver moves to the blood via osmosis

• returns to blood by lymphatic system

explain how an arteriole can reduce the blood flow into capillaries (2)

• muscle contracts

• narrowing the lumen

what blood vessel carries blood at the lowest pressure

vena cava

describe the advantages of the Bohr effect during intense excercise (2)

• increases dissociation of oxygen

• for aerobic respiration at the tissues

name and explain how a physiological change would allow for the removal of the increase in the volume of carbon dioxide (2)

• increases breathing rate

• has similar pCO2 per breath but more breaths

describe and explain the effect of increasing CO2 concentration on the dissociation of oxyhaemoglobin (2)

• increases oxygen dissociation

• by decreasing blood pH

give four safety precautions that should be followed when dissecting a heart (4)

• use a sharp scalpel

• wash hands

• disinfect bench

• cover any cuts

explain the role of the heart in the formation of tissue fluid

• contraction of ventricles produces high hydrostatic pressure

• forcing water out of blood capillaries

explain how the binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind (2)

• binding of first oxygen changes tertiary structure of haemoglobin

• which uncovers another binding site

Why do mammals require a double circulatory system

• To manage the pressure of blood flow

• So it flows through lungs at a lower pressure

• To prevent damage to the capillaries in alveoli

• And reduces the speed of blood flow

• Enabling more time for gas exchange

• Blood is then pumped at a higher pressure from heat to body

• To ensure that it reaches all the body cells

What are the unique properties of the cardiac muscles

• myogenic

• Therefore it can contract and relax without nervous hormonal stimulation

• It never fatigues

• as long as it has a constant supply of oxygen and glucose

Describe the structure of the arterioles

• Muscle layer is Thicker than arteries

• to help restrict blood flow into the capillaries

• Elastic layer is Thinner than arteries

• As pressure is lower

• Walls are thinner

• as pressure is lower

• Has no valves