4.3-circulation Flashcards
oxygen- where it enters and leaves blood
enters= capillaries of lungs
leaves= respiring tissues
carbon dioxide- where it enters and leaves blood
enters= respiting tissues
leaves= capillaries of lungs
glucose- where it enters and leaves the blood
enters= small intestine
leaves=respiring tissues
amino acids- where it enters and leaves blood
enters=small intestine
leaves=respiring tissues
hormones- where it enters and leaves blood
enters= glands
leaves= target cells
urea- where it enters and leaves the blood
enters= liver
leaves= kidney
mass transport in fish
-closed circulatory system
-2 chambered heart
-blood is oxygenated at gills and deoxygenated as it travels round body
mammalian mass transport- double circulatory system
- pulmonary- takes blood to lungs
2.systemic- takes blood around rest of body
4 things blood is made up of
-erythrocytes
-leukocytes
-platelets
-plasma
what can blood smears be used to diagnose
- anemia
- sickle cell disease
- blood cancers
- malaria
blood vessels- veins
-function to carry blood from tissues to the heart
-thin walls, mainly collagen aince blood at low pressure
-large lumen to reduce resistance flow
-valves prevent back flow
-low p
-blood usually deoxygenated (except pulmonary vein)
blood vessels- capillaries
-allows exchange of materials between blood and tissues
-very thin, permeable walls only one cell thick to allow exchange of materials
-very small lumen, blood cells must distort to pass through
-no valves
-blood p falls
-changes from oxygenated to de (except in lungs)
blood vessels- arteries
-carry blood from heart to tissues
-thick walls w smooth elastic layers to resist high pressure, muscle aids pumping
-small lumen
-no valves (except in heart)
-vessels at high p
-blood usually oxygenated (except pulmonary artery)
advantages of double circulatory system
-carries oxygen rich blood from heart to cells where oxygen is used
-carries deoxygenated blood to heart
-pulmonary circulation carries de blood from heart to lungs to be oxygenated
-makes sure oxy and deoxy cannot mix, so tissues receive as much as possible
-also means blood can be delivered at higher pressures
what are platelets
-tiny fragments of large cells called megakaryocytes, found in bone marrow
-involved in clotting of blood
erythrocytes (red blood cells)
-contain haemoglobin
-formed in bone marrow
-do not contain nucleus and only live around 120 days when matured
-transport oxygen from lungs to cells
-biconcave disc shape means large SA:V ratio so oxygen can diffuse in and out rapidly
-haemoglobin also carries CO2 produced in respiration to lungs
leukocytes (white blood cells)
-much larger than erythrocytes
-can still squeeze through blood vessels and change shape
-main function to defend against infection
-all contain a nucleus and colourless cytoplasm
types of leukocytes- granulocytes
-leucocytes with granules in cytoplasm that take up sain and have lobed nuclei
1. neutrophills- part of non specific, engulf and digest pathogens, make up to 70% leukocytes
2.eosinophills- non specific, stained be eosin stain, against parasites, allergic reactions and inflammation, develop immunity to disease
3.basophills- 2 lobed nuclei, non specific, produce histamines in inflammation and allergic reaction
types of leucocytes- agranulocytes
-do not have granules to take up stain, unlobed nuclei
1.monocytes- specific, largest of leukocytes, can move out of blood into tissues to form macrophages which engulf pathogens by phagocytosis
2. lymphocytes- small leukocytes- with very large nuclei vitally important in specific immune response
root of blood from vena cava (9 places)
1.vena cava
2.right atrium
3.right ventricle
4.pulmonary artery
5.lungs
6.pulmonary veins
7. left atrium
8.left ventricle
9.aorta
components of blood- plasma
major role in transporting;
-digested food products from small intestine
-nutrient molecules from storage to cells
-excretory products
-chemical messages
-also helps maintain steady body temp by transferring heat around system from deep rooted organs or very active tissues#
-acts as buffer to pH change
what is haemoglobin?
-protein made up of 4 polypeptide chains each with a haem (iron) group
-globular
-each haem can pick up 4 O2 molecules
-reversible reaction
-has an affinity for oxygen
-makes oxyhaemogloin
loading of oxygen on to haemoglobin- step by step
1.after first O2 binds, Hb changes shape, making it easier for polypeptide chains to bind to O2 molecules
2.therefore takes smaller inc in pO2 to bind second oxygen. (positive cooperativity) gradient of curve steepens
3.after third binds, should be easier for 4th
4. more difficult due to probability, with most binding sites occupied. gradient of curve flattens
the role of haemoglobin
-readily associates with oxygen at the surface where gas exchange takes place
-readily dissociates from oxygen at the respiring tissues to release oxygen in to respiring tissues
oxyhaemoglobin
Hb+4O2= HBO2
-reversible reaction, HBO2 is formed in lungs, when oxygen dissociates haemoglobin in body tissues it returns back to just Hb
loading and unloading of oxygen meaning
loading= process by which oxygen binds to haemoglobin (also called association) takes place in lungs
unloading= process by which haemoglobin releases oxygen (dissociating) takes place in tissues
affinity of haemoglobin
(chemical attraction to O2)
-can change under diff conditions
-shape can change in presence of some substances such as CO2
-if Hb has high affinity, it takes it up more easily and releases it less easily
-vice versa also true
high affinity haemoglobin
(curve to the left)
-loads oxygen easily
-releases less easily
-founds in organisms that live in environment with little oxygen
-these organisms have a low metabolic rate
-so slow release of oxygen in to tissues is not a problem
-more important to have Hb that takes up O2 rapidly than release it
low affinity haemoglobin
(curve to right)
-takes up oxygen less readily
-found in organisms that have plenty O2 in environment
-they have high metabolic rate
-rapid release of oxygen to tissues replaces that used in metabolism
-for these organisms its more important to release rapidly
important respitory pigments
- fetal- diff quaternary structure to adult
-higher affinity for O2 at same PO2 as adults
-loads at a PO2 where adult unloads
-maintains diffusion gradient across placenta
2.myoglobin- Mb
-higher affinity for PO2 than fetal and adult
-stors O2 in muscles- extending aerobic respiration
-only unloads at very low Po2 and very high CO2
-found in human muscles and diving organisms such as seals
partial pressure
-pressure exerted by a gas
PO2 or ppO2
ppO2 same as saying oxygen conc
-greater the oxygen in cells, the higher pO2
-as PO2 inc, becomes easier for oxygen to load to Hb
high pO2-oxygen loads onto Hb
low pO2-oxygen dissociates
the Bohr effect
-the greater the conc of cO2, the more readily the Hb releases its oxygen (low affinity)
oxygen dissociation curve
-S shape
Y axis=% saturation of Hb with oxygen
X axis left=ppo2 of oxygen
what 3 things is the human circulatory system made up of
blood vessels
blood
heart
what is the heart made up of
-2 atria, 2 ventricles
-septum so blood does not mix
-2 types of valve
-left atrioventricular (bicuspid)
-right atrioventricular (tricuspid)
-semilunar valve
-arteries pump blood away, veins to heart
systole definition
-period of contraction
-occurs in 2 stages because ventricles and atria contract seperately
diastole definition
-period of relaxation
-single phase as relaxation occur simultaneously in all chambers
general principles of the cardiac cycle
-contraction of myocardium generates pressure changes which result in orderly movement of blood
-blood flows from an area of high pressure to an area of low pressure, unless flow blocked by valve
-events on right and left sides of heart are same, but pressures are low on right
what happens in atrial systole
- atria full of blood and ventricles relaxed
- both atria contract and blood passes down in to the ventricles
- atrio ventricular valves open due to higher blood pressure in atria
- 70% of blood flows passively down to ventricles so atria do not have to contract a great amount
what happens in ventricular systole
- the atria relax
2.ventricle walls contract, forcing blood out
3.pressure of blood forces atrio ventricular valves to shut - pressure also causes semi lunar valves to open
5.blood passes into aorta and pulmonary arteries
diastole
- atria and ventricles are relaxed
2.bp in ventricles falls below that in arteries - high bp in arteries causes semi lunar valves to shut ‘dub’
4.all muscles in heart are relaxed
5.Blood from the vena cava and pulmonary veins enter the atria.
-cycle repeats
pressure changes during cardiac cycle
-When the atria and ventricles contract their walls press inwards REDUCING the volume inside but INCREASING the pressure, forcing the blood to move out.
-When the atria and ventricles relax the volume inside INCREASES but the pressure is REDUCED, allowing blood to enter.
what is the lub dub sound your heart makes
-caused by closing valves
-lub is atrio venticular valves closing at start of systole
-dub is when semi lunar valves close at end of ventricular systole
3 steps in cardiac cycle
-both atria contrcat (atrial systole)
-both ventricles contract (ventricular systole)
-all chambers relax (diastole)
3 things which control heartbeat
sinoatrial node (SAN) (pacemaker)
atrioventricular node (AVN)
purkyne (purkinje) tissue
control of heart beat in steps
- electrical impulse generated at SAN
- impulse travels to AV node
- causes atria to contract
- non conducting tissue between atria and ventricles. Impulses travel down bundle of His
- ventricles contract from apex upawrds
ventricular systole- including nodes and control
1.atria relax
2.pressure of blood causes atrio ventricular valves to shut ‘lub’
3.SAN stimulates AVN to produce impulses, these travel down the ventricles through bindle of HIS
4.purkyne fibres pass impulses to ventricle walls- there is a delay
5. this causes the ventricles to contract
6. pressure of blood opens semilunar valves, blood passes into aorta and pulmonary arteries
cardiac output equation
stroke volume (heart rate)
what does myogenic mean
-capable of contracting without nervous impulse
what is atherosclerosis
build up of plaques (fatty deposits) on the inside of arteries, this restricts or even blocks the flow of blood
-clots are likely to form in the coronary arteries or carotid arteries
-More likely to occur in arteries because the pressure in arteries is at a higher pressure, so more damage can occur to the endothelium.
blood clotting cascade e.g. when get a cut
- thromboplastin catalyses the conversion of prothrombin (large soluble protein) into another soluble protein called thrombin
- this requires calcium ions
- thrombin acts on another soluble plasma protein called fibrinogen, converting it to the insoluble fibrin
- this forms a mesh of fibres to cover wounds
- platelets and blood cells get trapped in the fibrin mesh, forming a clot
- special proteins in the structure of the platelets contract, making the clot tighter and tougher to form a scab
- this helps protect the skin and vessels underneath while they heal.
risk factors of atherosclerosis
- smoking- chemicals can damage artery lining
- lifestyle e.g. drinking, lack of activity, diet, stress
- type 2 diabetes- can result in damage to lining of blood vessels
4.genes - age
- sex- men more likely as oestrogen reduces plaque build up
