3.1.2 - transport in animals🫀 Flashcards
features of a circulatory system
liquid transport medium that circulates around the body
vessels that carry the transport medium
pumping mechanism
open circulatory system
very few vessels to contain the transport medium
haemocoel
open body cavity
comes into direct contact with the tissues and the cells
where open circulatory systems are found
invertebrate animals, including most insects and some molluscs.
haemolymph
transport medium in insects
does not carry o2 or co2, transports waste products
where closed circulatory systems are found
all of the vertebrate groups, including mammals
single closed circulatory system
blood flows through the heart and is pumped out to travel all the way round the body before returning to the heart
process of a single closed circulatory system
- blood passes through two sets of capillaries before it returns to the heart
- in the first it exchanges o2 and co2
- in the second substances are exchanged between blood and cells
- very low efficiency
why can fish use a single closed circulatory system?
body weight supported by the water which they live in and do not have to maintain their own body temperature - reducing metabolic demands.
double closed circulatory system
most efficient system for transporting substances around the body.
involves two separate circulations
process of double closed circulatory system
blood is pumped from the heart to the lungs to pick up oxygen and unload co2 and then returns to the heart
blood flows through the heart and is pumped out to travel all around the bidy before returning to the heart again
elastic fibres
composed of elastin and can stretch and recoil providing vessel walls with flexibility
smooth muscle
contracts and relaxes which changes the size of the lumen (the channel within the blood vessel)
collagen
provides structural support to maintain the shape and volume of the vessel
arteries
blood vessels that carry blood away from the heart. they carry oxygenated blood - this blood is under very high pressure
structure of arteries
artery walls contain elastic fibres, smooth muscle and collagen. lining of the artery is smooth so the blood flows easy over it
small lumen
arterioles
link the arteries and the capillaries
structure of arterioles compared to arteries
more smooth muscle
less elastin
vasoconstriction
smooth muscle contracts in the arteriole, constricting the vessel and prevents blood flowing into the capillary bed
vasodilation
smooth muscle relaxes in arteriole, blood flows through the capillary bed
capillaries and their adaptations
microscopic vessel through which exchange takes place between blood and cells
- large surface area
- total cross sectional area is always greater than the arteriole supplying them to rate of bloof flow falls
- walls are one cell thick
veins
blood vessels that carry blood back to the heart. they carry deoxygenated bood
structure of veins
walls have lots of collagen and relatively little elastic fibre
wide lumen and smooth thin lining
venules
small vessels that gather blood from capillaries into the veins
structure of venules
very thin walls with little smooth muscle
adaptations of veins
- one way valves at intervals to prevent blood flowing backwards
- bigger veins run through big active muscles in the body. when they contract the veins squeexe forcing blood to the heart
plasma
yellow liquid, carrying a wide range of components
platelets
fragments of large cells called megakaryocytes found in the red bone marrow
involved in blood clotting
functions of blood
transport 02, co2, digested food, waste products, hormones, cells and antibodies in the immune reponse
maintain body temp
pH buffer
oncotic pressure
pressure of water to move as a result of the prescence of plasma proteins, which have a low water potential
hydrostatic pressure
the pressure within a blood vessel that tends to push water out of the vessel
hydrostatic pressure at arterial end
very high
tissue fluid
fluid surrounding the cells and tissues
venous end pressure
hydrostatic pressure falls
oncotic pressure remains the same
lymph
tissue fluid that has entered a lymphatic capillary
lymph composition
similar tp plasma and tissue fluid
less o2 and fewer nutrients
has fatty acids
where lymph returns to the bloodstream
under the collarbone
haemoglobin
the protein that carries oxygen in the red blood cells. globular protein made up of 4 peptide chains, each iwth an iron- containing haem group
oxyhaemoglobin
combination of Hb and o2
Hb + 4o2 (reversible reaction) Hb (02)4
positive cooperativity
once the first oxygen binds haemoglobin will undergo a conformational change so its easier for the next 3 oxygens to bind
myogenic
generates its own beat
diastole
relaxation of the heart
systole
contraction of the heart
cardiac cycle
a complete heart beat constisting of contraction and relaxation of both atria and both ventricles
lub dub
the sound made by the heart valves as they close
SA node
specialised cells in the wall of the right atrium
called the pacemaker because it can alter the heart rate by altering the number of action potentials conducing through the heart
starts the atria contracting
AV node
a node of specialised heart muscle located in septal wall of RA - recieves impulses from the SA node and transmits them to the AV bundle
bundle of his (AV bundle)
located next to the AV node. provides the transfer of the electrical impulse from the atria to the ventricles
purkinje fibres
fibres in the ventricles that transmit impulses to the right and left ventricles, causing them to contract.
purpose of the AVN delay
to ensure that the atria have stopped contracting before the venticles start
what an ECG measures
tiny electrical differences in your skin, which result from the electrical activity of the heart
tachycardia
abnormally rapid heartbeat
bradycardia
slow heart rate
ectopic heartbeat
extra beats that are out of the normal rhythm
atrial fibrilation
occurs when the normal rhythmic contractions of the atria are replaced by rapid irregular twitching of the muscular heart wall
oxygen disocciation curve
percentage saturation haemoglobin in the blood is plotted agaisnt partial pressure of oxygen
show affinity of haemoglobin for oxygen.
what happens at low partial pressure for oxygen
low affinity for oxygen so readily disocciates
what happens at high partial pressure for oxygen
high affinity for oxygen so readily associates’
bohr effect
the rise in co2 meaning that haemoglobin gives up more oxygen, shifts the curve ti the right
fetal haemoglobin
higher affinity for oxygen than adults, so the curve shifts to the left.
carbaminohaemoglobin
co2 combined with amino acid groups in polypeptide chains of haemoglobin
carbonic anhydrase
catalyses the reversible reaction between co2 and water to form carbonic acid.
carbonic acid disociates to form..
hydrogen carbonate ions and hydrogen ions
chloride shift
negtative hydrogen carbonate ions move out of the erythrocytes and cloride ions move in.
