Definition of double circulatory system
One in which blood flows through the heart twice for each circuit of the body
Definition of single circulatory system
One in which the blood flows through the heart once for each circuit of the body
Definition of transport
Movement of substances and heat around the body
Definition of arteries
Vessels that carry blood away from the heart
Definition of arterioles
Small blood vessels the distributed blood from an artery to capillaries
Definition of capillaries
Very small vessels with very thin walls
Definition of closed circulatory system
One in which the blood is held in vessels
Definition of open circulatory system
One in which the blood isn't held in vessels
Definition of veins
Vessels that carry blood back to the heart
Definition of venules
Small blood vessels that collect blood from capillaries and lead into the veins
Definition of blood
The fluid used to transport materials around the body
Definition of hydrostatic pressure
The pressure that a fluid exerts when pushing against the sides of a vessel or container
Definition of lymph
The fluid hold in the lymphatic system which is a system of tubes that returns excess tissue fluid to the blood system
Definition of oncotic pressure
Depression created by the osmotic effects of the solutes
Definition of plasma
The fluid portion of the blood
Definition of tissue fluid
The fluid surrounding the cells and tissues
Definition of atrioventricular valves
Valves between atria and ventricles which ensures blood flows in the correct direction
Definition of cardiac muscle
Specialised muscle found in the walls of heart chambers
Definition of semilunar valves
Valves prevent blood re-entering heart from arteries
Definition of cardiac cycle
Sequence of events in one full beat of the heart
Definition of affinity
A strong attraction
Definition of dissociation
Releasing the oxygen from the oxyhaemoglobin
Definition of fetal haemoglobin
Type of haemoglobin found in the foetus
Definition of haemoglobin
Red pigment used to transport oxygen in the blood
Definition of carbonic anhydrase
Enzyme that catalyses the combination of carbon dioxide and water
Definition of chloride shift
The movement of chloride ions into the erythrocytes to balance the charge as hydrocarbonate ions leave the cell
Definition of Bohr effect
The effect the extra carbon dioxide has on the haemoglobin explaining the release of more oxygen
Definition of haemoglobinic acid
Compound formed by the buffering action of haemoglobin is it combines with excess hydrogen ions
Definition of bradycardia
Slow heart beat
Definition of ectopic heartbeat
Extra beat or early beat of the ventrioles
Definition of electrocardiogram
Trace that records electrical conductivity of heart
Definition of fibrillation
Uncoordinated contraction of atria and ventricles
Definition of myogenic muscle
Muscle that can initiate its own contraction
Definition of Purkyne tissue
Consists of specially adapted muscle fibres that conduct wave of excitation from AVN down septum to ventricles
Definition of SAN (sino-atrial node)
Hearts pacemaker
Definition of tachycardia
Rapid heart rhythm
Mammalian heart is a …
Muscular pump divided into 2 sides
What does each side of the heart do?
Right - pumps deoxygenated to lungs to become oxygenated
Left - pumps oxygenated to body
What does both sides of the heart do?
Squeezes blood, putting it under high pressure, forcing it along arteries and through circulatory system
Where does the heart lie?
Left side of chest cavity
What does the main part of the heart consist of?
Cardiac muscle
What lies over the surface of the heart and what do they do?
Coronary arteries
Supply oxgenated blood to heart muscle
What happens if the coronary arteries are blocked?
Restricts blood flow to the heart, reduces delivery of O2 and nutrients
May cause angina or heart attack (myocardial infarction)
What are the 4 chambers of the heart?
Top 2 atria
Bottom 2 ventricles
What do the atria do?
Recieve blood from major arteries
What flows into the right atrium?
Deoxygenated blood from body through vena cava
What flows through left atrium?
Oxygenated blood from lungs through pulmonary vein
Where does the blood flow after the atria?
Down through atrio-ventricular valves to ventricles
What are attached to the atrio-ventricular valves and what do they do?
Tendious cords - prevents valves turning inside out when ventricular walls contract
What seperates the ventricles?
Septum
What does the septum do?
Seperates ventricles - ensures deoxygenated blood kept on left side and oxygenated on right
What leaves the right ventricle and to where?
Deoxygenated blood flows into pulmonary artery leading to lungs to become oxygenated
What leaves the left ventricle and to where?
Oxygenated blood flows into aorta carrying oxygenated blood for body
What are found at the bottom of the major arteries and what do they do?
Semi-lunar valves - prevent blood returning to heart when ventricles relax
What does cardiac muscle structure consist of?
Fibres that branch forming cross bridges
What do the fibres in cardiac muscle do?
Help spread stimulus around heart and ensures muscle can produce squeezing action rather than simple reduction in length
What are found betweeen the myofibrils (muscle fibrils) and why?
Mito to supply energy needed for contraction
What are cardiac muscles seperated by and what do these do?
Intercalated disks - facilitate synchronised contraction
What is each cardiac muscle cell divided into?
Contractive units called sacromeres
Cardiac muscle cells have a nucleus
What creates the pressure in blood?
Contraction of cardiac muscle in chamber walls
The higher the pressure of blood …
The further the blood is pushed
How thick are the walls of the atria and why?
Thin as don’t need to create much pressure - function to recieve blood from veins and push into ventricles
How thick are the walls of the right ventricle?
Thicker than walls of atria - enables to pump blood out heart as pumps deoxygenated blood to lungs however lungs in chest cavity besides heart to blood doesn’t need to travel very far. Alveoli alos very edlicate so may be damaged at high pressure
How thick are the walls of the left ventricle?
Thicker than right - blood pumped out through aorta and needs sufficient pressure to overcome resistance of systematic circulation (needs enough pressure to pump around body)
How is CO2 transported through the circulatory system?
Dissolved in plasma
Associated with Hb
Transported as hydrogen carbonate ions
Where is CO2 released from?
Respiring tissues
How are HCO3- ions formed to transport CO2?
CO2 in plasma diffuses into RBC’s and combines with H2O forming weak acid - carbonic acid (catalysed by carbonic anhydrase)
Carbonic acid dissociates to release H+ and HCO3- ions
HCO3- ions diffuse out RBC into plasma
Reaction to form carbonic acid
CO2 + H2O → H2CO3
Reaction to form hydrogen carbonate ions
H2CO3 → H+ + HCO3-
Formation of HCO3- ions:
How is the charge maintained in RBCs when HCO3- ions diffuse out?
By movement of Cl- ions from plasma into RBC - chloride shift
What could the build up of H+ ions in RBCs do?
Cause contents of RBC to become very acidic
How is the build up of H+ ions in RBCs prevented?
H+s taken out of solution by associating with haemoglobin to form haemoglobinic acid (HHb) - haemoglobin acts as buffer
How does blood entering respiring tissues carry O2?
Oxyhaemoglobin
Which has a lower partial pressure of O2 and why:
Lung tissue
Respiring tissue as O2 used up in respiration
How does increasing CO2 conc affect transportation of CO2?
Areas of higher CO2 conc have lower partial pressure of O2. As result, oxyhaemoglobin begins to dissociate and releases O2 to tissues meaning haemoglobin available to take up H+ ions, forming haemoglobinic acid
Why is there more O2 dissociation in respiring tissues?
H+ ions compete with O2 to combine with Hb
Respiring tissues - more CO2 produced, more carbonic acid produced, more H+ dissociated, more comp for Hb, more O2 dissociation
What does the Bohr effect describe?
Effect of increasing CO2 conc on haemoglobin
What happens once CO2 enters RBCs?
Forms carbonic acid which dissociates to release H+ ions
What do the H+ ions affect in RBCs?
pH of cytoplasm making it more acidic therefore affecting the tertiary structure of Hb
What does increasing the acidity of a Hb molecule do?
Alters tertiary structure and reduces the affinity of the Hb for O2
What happens when the affinity of Hb for O2 is reduced?
Hb unable to hold as much O2 and O2 is released from the oxyhaemoglobin to the tissues
Where tissues respiring more, will be more CO2 produced therefore more H+ produced in RBCs making oxyhaemoglobin release even more O2
What happens to Hb molecules when more CO2 is present?
Becomes less saturated with O2
How does the Hb dissociation curve move with the Bohr effect (the Bohr shift)?
Shifts downwards and right
What does the Bohr effect result in?
More O2 being released where more CO2 is produced in respiration
Where is the blood in closed circulatory systems?
In vessels
What are the advantages of a closed circulatory system?
High pressure so blood flows more quickly
More rapid delivery O2 and nutrients
More rapid removal CO2 and waste
Transport independent to body movement
Where is the body fluid in a open circulatory system?
Circulates body cavity so tissues and cells bathed
How is blood/body fluid moved in open circulatory systems?
Movements of body (without movement, blood stops moving and transport O2 and nutrients stop)
Muscular pumping organ (similar to heart) - long muscular tube lies under dorsal surface of body
Describe how the pumping organ in open circulatory systems work (e.g in insects)
Blood enters from body via pries called Ostia and pumps blood towards head by peristalsis. At forward end of heart, blood pours out into body cavity.
Larger and more active insects - open ended tubes attached to muscle to direct blood to active parts of body
Disadvantages of open circulatory system
Low BP and blood flow slow
Circulation may be affected by movements or lack of
What's the inner layer/lining of blood vessels called?
Endothelium
Is the endothelium rough or smooth and why?
Smooth - reduce friction with flowing blood
What do arteries do?
Carry blood away from heart
Are artery walls thick or thin and why?
Thick as blood at high pressure
Is an artery lumen small or big and why?
Small to maintain high pressure
Why are the inner walls of arteries folded?
To allow artery to expand as blood flow increases
What 3 layers make up artery walls?
Inner layer (tunica intima)
Middle layer (tunica media)
Outer layer (tunica adventitia)
Describe the inner layer of artery walls
Consists thin layer elastic tissue to allow walls stretch and recoil to maintain BP
L
Describe the middle layer of artery walls
Consists thick layer smooth muscle
Describe outer layer of artery walls
Thick layers collagen and elastic tissue. Provides strength withstand high pressure then recoil to maintain pressure
Which arteries have more elastic tissue in their walls and why?
Nearer heart to allow stretch and recoil to help even out fluctuations in bp created by heart
Which arteries have more muscle tissue in their walls?
Further from heart
What do arteriole walls contain?
Layer smooth muscle
What does contraction of smooth muscle in arteriole walls do?
Constricts diameter of arteriole, increasing resistance to flow and reduces rate blood flow
What's the constriction of arteriole walls used for?
Divert blood flow to regions body demanding more O2
Do caps have thick or thin walls and why?
Thin to allow exchange of materials between blood and tissue fluid
Do caps have narrow or wide lumen?
Narrow
Why do caps have narrow lumens?
RBCs squeeze against walls of caps - helps transfer of O2 as reduces diffusion path and increases resistance and reduces rate of flow
What do cap walls consist of and why?
Single layer flattened endothelial cells to reduce diffusion distance for exchange
Why are cap walls leaky?
Allow plasms and dissolved subs to leave blood
What do venule walls consist of?
Thin layers muscle and elastic tissue outside endothelium and thin outer layer of collagen
What do veins do?
Carry blood back to heart
Do veins have thick or thin walls and why?
Relatively thin - blood at low pressure
Do veins have a narrow or wide lumen and why?
Wide to ease flow of blood
Why do vein walls have thinner layers of collagen, muscle and elastic tissue than arteries?
Don't need to stretch and recoil and not actively constructed to reduce blood flow
What do veins contain that arteries don't and why?
Valves prevent backflow
What does it allow since the walls of veins are thin?
Can be flattened by action of surrounding skeletal muscle
What does the contraction of skeletal muscle surrounding veins do?
Applies pressure to blood forcing to move along in direction determined by valves
What’s the role of the heart?
Create pressurethat pushes blood through blood vessels
What’s the cardiac cycle?
Coordinated sequence of contraction of muscular walls which allows heart to fill with blood before pumpiing it around body
Summarise ventricular systole
Both ventricles pump togther
Contraction starts at apex of heart so blood pushed upwards towards arteries
Summarise diastole
All muscular walls relax
Elastic recoil causes chambers to increase in vol allowing blood to flow in from veins
Summarise atrial systole
Both atria contract together
Walls thin so small increase in pressure created by contraction which helps push blood into ventricles, stretching their walls and ensuring they’re full of blood
What do valves do?
Ensures blood flows in correct direction - prevent backflow
What are valves opened and closed by?
Changes to BP in various chambers
Atrial systole:
SL valves =
AV valves =
Atria =
Close
Open
Contract
Ventricular systole:
Ventricles =
Diastole:
Closed
Relax
Describe what happens after systole
Ventricular walls
Pressure in ventricles
Blood in atria
Blood entering heart
Pressure in atria and ventricles
Valves
Closure caused by
relax and recoil
rapidly drop below pressure in atria
pushes AV valves open
flows straight through atria into ventricles
slowly rises as fills with blood
remain open while atria contracts but close when begins to relax
swirling action in blood around valves when ventricles full
What causes AV valves to close?
Swirling action in blood around valves when ventricles full
Describe what happens as the ventricles contract (systole)
BP
Blood moves
Tendious cords attached to valves
in ventricles rise
upwards when BP higher than atria
prevent them from turning inside out - preventing backflow
What does ventricular systole do to the BP in ventricles?
Raises it rapidly
Why are the SL valves closed before ventricular contraction?
BP in major arteries higher than ventricles
Describe what happens once ventricular systole has increased the BP in the ventricles
Once BP ventricles higher than major arteries
Blood pushed
Heart muscles
Elastic tissue
Blood flows
SL valves
SL valves pushed open
out in powerful spurts as blood under very high pressure
Relax once ventricle walls finished contraction (diastole)
in ven walls recoils causing BP drop quickly
back towards ven as BP drops below pressure in major arteries
pushed closed by blood collecting in valve pockets - prevents backflow
What is the pulse?
Pressure wave created when SL valves close
Describe the pressure changes during diastole
Ventricular pressure drops rapidly and falls below P of major arteries
Once ven P below atrial P, AV open
Describe the pressure changes during atrial systole
P all chambers increases slowly as fill with blood
AV remain open as atrial P remains higher than ven P
Describe the pressure changes during ventricular systole
Ven P increases rapidly
AV close resulting slow decrease in atrial P
Once ven P higher than major arteries, SL open
How do artery walls help create even flow?
Lots of elastic tissue
As blood leaves heart, walls stretch
As blood moves out of aorta, pressure in aorta drops
Elastic recoil helps maintain BP
Further blood flows along artery, further BP drops and fluctuations become less obvious
Wht creates the lub-dub sound?
Lub = AV closing and SL opening
Dub = AV opening ad SL closing
Label the diagram
AV valves closing
SL opening
SL closing
AV opening
Systole
Diastole
Calcualting HR
60/BPM
Cardiac output (ml/min) =
stroke vol (ml) x HR (BPM)
Sius rhythm
Normal heartbeat
Bradychardia
Slow HR
Tachycardia
Fast HR
Atrial fibrilation
Atria beating more frequently than ventricles - no clear P waves
Ectopic heartbeat
Early ventricle beat - patients feels missed a heartbeat
What do electrocardiograms do?
Measure electrical activity of heart
What do P waves show?
Excitation of atria (atrial stimulation)
What does a QRS wave show?
Excitation of ventricles (ventricular stimulation)
What do T waves show?
P
Q
R
S
T
Atrial fibrillation
Bradycardia
What does the SAN do?
Initiates wave of excitation at regular intervals (generates electrical activity)
Regular human heartbeat
55-80 BPM
What is the heart described as and why?
Myogenic as initiates its own contractions
Which contracts at a higher frequency?
Describe how the ventricles contract
Wave carried from
At base of septum
As wave spreads
Ventricles contract
AVN down Purkyne tissue
Wave spreads out over walls of ventricles
Upwards from apex of ventricles, causes muscle to contract
From base upwards pushing blood up towards maj arteries at top of heart
What’s involved in the conduction system?
SAN
AV node
Bundle of His
Purkyne fibres
How is a heartbeat generated?
SAN sends wave depolarisation across atria causing atrial systole
Band non-conducting fibres block nerve impulse from going any further, causing the AV delay
AVN stimulated and sends wave depolarisation dow bundle of hus and up through purkyne fibres
Causes ventricular systole and ventricles contract from apex
Describe the contraction of the atria
Wave of excitation
Wave travels along
Tissues at base of atria
AVN
Spreads over walls of both atria
Membranes of muscle tissue causing cardiac muscle cells contract
Unable to conduct wave so can’t spread directly down ventricular walls
Conducts wave to ventricles
The heartbeat:
Why is the wave delayed in the AVN?
Allows time for atria to finish contracting and for blood to flow down into ventricles before they begin to contract
Hydrostatic pressure in plasma
High
Hydrostatic pressure in tissue fluid
Low
Hydrostatic pressure in lymph
Oncotic pressure in plasma
More negative
Oncotic pressure in tissue fluid
Less negative
Oncotic pressure in lymph
Cells found in plasma
RBC
Neutrophils
Lymphocytes
Cells found in tissue fluid
Some neutrophils - especially infected areas
Cells found in lymph
Proteins found in plasma
Plasma proteins
Are proteins found in tissue fluid?
Few
Are proteins found in lymph?
Where are more fats found in lymph?
Near digestive system
How are fats transported in plasma?
In lipoproteins
Are fats found in tissue fluid?
What happens if a tissue becomes infected and why?
Caps become more leaky and more fluid directed into lymph system
Helps direct bacteria towards lymph system
What influences the movement of fluid in and out of caps?
Hydrostatic pressure of blood
Hydrostatic and oncotic pressure of tissue fluid
What does the hydrostatic pressure of blood do?
Push fluid into tissues
What does hydrostatic pressure of tissue fluid do?
Push fluid into caps
What does oncotic pressure of blood do?
Pull water back into blood
What does the oncotic pressure of tissue fluid do?
Pull water into tissue fluid
The oncotic pressure of blood
Net pressure (kPa) =
net hydrostatic - net oncotic
What are lymph nodes?
Swellings found at intervals along lymphatic system
What happens to the tissue fluid that doesn’t re-enter the blood?
Drained into lymphatic system
What does the lymph system do?
Drains excess fluid out of tissues and returns it to blood system in subclavian vein in chest
What does lymph contain and why?
Lymphocytes as produced in lymph nodes
Hydrostatic pressure at arterial end of caps
What does tissue fluid do?
Bathes tissues
Transports O2 and nutrients to cells and removes waste and C02
Why is BP lower at venous end of cap?
Allows some of tissue fluid to return to cap carrying waste subs nad CO2 into blood
What’s oncotic pressure?
Pressure created by difference in WP of 2 liquids across semi-peremeable membrane
Which has a higher BP in a cap?
Why is does blood have high hydrostatic pressure at arterial end of cap?
To push blood fluid out of caps through cap walls
What remains in blood when tissue fluid formed and why?
All blood cells and plasma proteins as too large to pass through gaps in caps walls
Why does tissue fluid surround body cells?
So exchange of gases and nutrients can ooccur across plasma membrane
How does exchange of gases and nutrients occur from tissue fluid to body cells?
Diffusion
Facilitated diffusion
AT
Role of platelets
Stop bleeding and aid blood clotting
Role of leukocytes
Aid body in immune response by ingesting, digesting or killing foreign organisms
Where are platelets and leukocytes found?
In the buffy coat
What does plasma contain?
Dissolved subs:
O2
CO2
Minerals
Glucose
AAs
Hormones
How is tissue fluid formed?
By plasma leaking from caps
How does plasma leak from caps?
Mass flow (NOT diffusion)
What’s the need for a transport system?
Supply O2 and nutrients to grow and survive
Remove waste products so don’t build up and become toxic
Why do larger animals need a transport system?
Have 2 layers of cells so diffusion distance too long and diffusion alone take too long to supply all requirements
What factors influence need for a transport system?
Size
SA:V Ratio
Level metabolic activity
How does the size of an organism affect its need for a transportation system?
Larger organism = cells inside further from surface so diffusion distance increased - diffusion rate reduced and to slow to supply all requirements
Outer layers cells use up supplies so less reach cells deep in body
Small animals
Large animals
What does having a small SA:V ratio mean?
For each gram tissue in body, have sufficient area of body surface for exchange to occur
How does level of metabolic activity affect the need for a transport system?
If very active - need good supply nutrients and O2 to supply energy for movement
Animals needing to keep themselves warm need even more energy
Features of an effective transport system
Fluid/medium to carry nutrients, O2 and waste around body (blood)
Pump to create pressure to push fluid around body (heart)
Exchange surfaces to enable subs to enter and leave blood (caps)
Tubes/vessels to carry blood by mass flow
2 circuits - one to pick up O2 and one to deliver
Route blood takes through fish
Heart -> Gills -> Body -> Heart
What does it mean to have a single circulatory system?
Blood flows through heart once for each circuit of body
Fish
What 2 systems do mammals have?
Pulmonary circulation - Carries blood to lungs pick up O2
Systematic circulation - Carries O2 and nutrients to tissues
Route blood takes through mammals
Heart -> Body -> Heart -> Lungs -> Heart
Mammals
Superior Vena cava
Semi lunar valve
Tricuspid valve
Right atria
Inferior Vena cava
Right ventricle
Aorta
Left atria
Left ventricle
Pulmonary artery
Pulmonary vein
Bicuspid valve
Pericardium
Hb + oxygen →
Hb + carbon monoxide →
Carboxyhaemoglobin
Hb + carbon dioxide →
Carbaminohaemoglobin
Hb has affinity for …
Oxygen
How are erythrocytes adapted for their function?
Biconcave shape - maximises SA for gas exchange
Small and flexible - pass through narrow caps
No nucleus - more room for Hb and respiratory gases
Packed with Hb
How is Hb transported?
In RBCS
Describe Hb
Complex protein 4 subunits. Each subunit has 1 polypeptide chain and haem group
What do haem groups contain?
Single iron ion (Fe2+)
What can the iron ion in the haem group do?
Attracts and holds O2 molecule
How many oxygen can a haem group hold?
1
How many O2 molecules can a haemoglobin molecule hold?
4
What does the ability of Hb to associate with and release O2 depend on?
Conc of O2 in surrounding tissue
How is the conc of O2 in tissue measured?
By relative partial pressure that it contributed to a mixture of gases (partial pressure of O2 (pO2))
What's pO2 measured in?
kPa
When would a graph of % saturation against O2 tension be linear?
In a normal liquid, where conc of O2 absorbed into liquid is directly proportional to O2 tension in surrounding air
What shape is a haemoglobin association curve?
S shaped
How is oxygen transported around body?
Absorbed into blood from alveoli
Binds reversibly to haemoglobin (associates) on RBC - takes O2 out of solution so maintains a steep conc grad allowing more O2 to enter blood from lungs
Carried around body to respiring cells/tissues - dissociates from oxyhaemoglobin (for aerobic resp)
What’s association like at low O2 tension and why?
Hb doesn’t readily associate - haem groups that attract O2 molecules in centre of Hb molecule making it difficult for O2 molecule to reach and bind with it
What accounts for the low saturation level of Hb at low O2 tensions?
Difficulty for first O2 molecule to bind with haem group
What happens as O2 tension rises and why?
Hb readily associates - diffusion grad into Hb molecule increases so O2 molecule enters Hb molecule and binds with haem group
What happens when the first O2 molecule binds to the haem group?
Causes slight change in shape of Hb molecule - conformational change
What does the conformational change allow?
More O2 molecules to bind enter Hb molecule and bind with other haem groups relatively easily
What accounts for the steepness on the association curve and why?
The conformational change as allows other O2 molecules to bind more easily
What happens to the dissociation curve as Hb reaches 100% saturation and why?
Levels off/plateaus - 2nd and 3rd molecules bind more easily but 4th more difficult to associate as Hb molecule becomes full
Why does the association curve start off less steep?
Difficult to bind first O2 molecule as Hb has to change shape
Is pO2 high or low in respiring tissues?
Is pO2 high or low in lungs?
When pO2 is low, O2 …
Dissociates from oxyhaemoglobin into respiring cells/tissues
When does Hb has a high affinity?
When it binds easily and dissociates slowly
When does Hb have a low affinity?
Binds slowly and dissociates easily
At a low pO2, Hb has a _ affinity for O2.
low
How does the dissociation curve for foetal Hb change from adults and why?
Curve moves left - foetal Hb must be able to bind with O2 in enviro where pO2 low enough to make adult Hb release O2
Which has a higher affinity for O2?
How does foetal Hb get its O2?
In placenta (low pO2), foetal Hb absorbs O2 from surrounding fluid - reduces pO2 further and as result O2 diffuses from mothers blood to placenta which reduces tension in mothers blood making maternal Hb release more O2
How would the dissociation curve change for a lugworm compared to a humans and why?
Steeper and to L - Not very active and covered by sea water so obtains O2 from water adn diffuses into blood. Tide goes out, pO2 levels in burrow decreases so needs extrat as much O2 from remaining water as possible
How would the dissociation curve change for a mouse compared to a humans and why?
Moves R - small active mammals, large SA:V, rapidly loses heat, high metabolic rate to allow maintain body temp
How can blood flow be sped up?
Increase BP created by heart
Why are fish able to survive with a single circulatory system?
Not metabolically active as mammals as don’t maintain body temp - need less E so single delivers sufficient O2 and nutrients
Why do mammals need a double circulatory system?
Active and maintain body temp - need more E to keep warm and for activity (requires energy from food). Energy released from food through respiration so to release lots of E - cells need good supply O2 and nutrients and removal of waste
What are the disadvantges of a single circulatory system?
Bp drops as passes through tiny caps of gills
Blood has low pressure and flows slowly
Rate which delivers O2 and nutrients and removes waste slow
What are the advantages of a double circulatory system?
Blood under lower pressure in pul circ so doesn’t damage caps in lungs but can then be pumped to make it flow faster when back through heart
Blood under higher pressure = faster
Quicker delivery of O2 and nutrients and removal of waste
Foetal Hb curve
Llama Hb curve
Mouse Hb curve
Lugworm Hb curve
Hb dissociation curve
Bohr effect Hb curve
Zuletzt geändertvor einem Jahr
