4.3 Flashcards
what are erythrocytes
RED BLOOD CELLS
Erythrocytes are adapted for transporting oxygen.
They contain haemoglobin, a protein which carries the oxygen and gives them the red colour.
The blood also carries away carbon dioxide produced during respiration by cells
what is heamaglobin
Haemoglobin is made up of:
1. 4 polypeptide chains
2. each polypeptide chain contains a haem group which contains an iron ion
Each haem can pick up 4 molecules of oxygen
what is the reaction of heamaglobin and oxygen
Hb + 4O2 ⇌ HbO8
Haemoglobin + oxygen = oxyhaemoglobin
This is reversible.
Oxyhaemoglobin is formed in the lungs, then when oxygen unloads (leaves) oxyhaemoglobin in the body tissues it turns back to haemoglobin.
Once one O2 molecule loads it makes it easier for other O2 molecules to then load. But as it becomes saturated it becomes harder for more to load.
what is partial pressure
pO2
the concentration of oxygen
when does oxygen load onto haem
when the pO2 is high
when it is low it unloads
what is the graph
shape
labels
ADD GRAPH
sigmoidal shape - 4 molecules
1st harder
2+3 easier
4 hard
never 100% as there is always blood moving
bohr shift to right
curve to the left
high affinity for oxygen
loads oxygen easily.
Releases it less readily.
Found in organisms that live in environments with little oxygen (i.e. low PPO2).
E.g. lugworms.
These organism must have a low metabolic rate.
I.e. respire or use oxygen slowly.
So the slow unloading of oxygen into the tissues is not a problem.
For these organisms it is more important to have a Hb that loads oxygen rapidly than unloads it.
curve to the right
low afinity to oxygen
loads oxygen less readily.
unloads more readily.
Found in organisms with that live in environments with plenty of oxygen (i.e. high PPO2)
E.g. humans.
These organisms have a high metabolic rate.
I.e. respire and use oxygen readily.
So rapid release of oxygen to the tissues replaces that used (in metabolism).
For these organisms it is more important to have a Hb that unloads oxygen more rapidly than load.
feotal haemoglobin
Has a different quaternary structure to adult Hb.
Has a higher affinity for O2 at the same P02 as adult Hb.( shifts to the left)
Loads/associates at a PO2 at which the adult Hb dissociates.
Maintains a diffusion gradient across the placenta.
myoglobin
Has a higher affinity for O2 than adult and fetal Hb.
(shifts a lot to the left) - different shape
Stores O2 in the muscle – extending aerobic respiration.
Only unloads/dissociates when the PO2 is very low/CO2 high.
Found in human (muscles) and diving organisms e.g. seals -areas where contractions are sustained.
erythrocytes
red blood cell
contain haeomoglobin
no nucleus
transport oxygen from the lungs to the cells
biconcave disc shape ( large surface area to volume ratio)
leucocytes
larger than erythrocytes
defend the body against infection
nucleus and cytoplasm
granulocytes
leucocytes
granuals in the cytopasm to stain them
lobed nuclei
neutrophils
type of granulocyte
non specific immune system
engulf and digest pathogens by phagocytosis
multi lobed nuclei
eosinophils
type of granulocyte
non specific immune system
stained red
important in non specific immune response against parasites in allergic reactions and inflamation
basophils
type of granulocyte
non specific immune system
two lobed nucleus
produce histamines in allergic reaction and inflammation
agranulocyte
leucocytes do not have granules
unlobed nuclei
monocyte
agranulocyte
specific immune system
largest leucocyte
move out of the blood and into tissues to form macrophages
engulf pathogens by phagocytosis
lymphocytes
type of white blood cell
small leucocytes with very large nuclei that are vitally important in specific immune response of the body
platelets
tiny fragments of large cells called megakaryocytes
involved in clotting of the blood
vein
cary blood back towards the heart
most cary deoxgyenated
except
-pulmonary
-umbilical
thin layer of muscle and few fibres
large lumen
adaptation of veins
hold large volumes of blood
low pressure
semilunar valves to prevent backflow of blood
during physical activity the muscles squeeze the veins forcing the blood back to the heart
capillaries
branch between cells so
substances can diffuse between cells and the blood quickly
diameter is small encouraging more diffusion
thin walls
oxygen out of blood
co2 and waste products in
walls are partially permeable
artery
carry blood away from the heart towards cells
almost all carry oxygenated blood
except
-pulmonary
-umbilical
lumen- central space
elastic fibres and muscle around the outside
then external later of tough tissue
adaptations of the artery
lumen-central space gets smaller as you get away from the heart
elastic fibres and muscle tisues get larger as you move away
high pressure of blood to withstand
stretch to accommodate pressure
pulse you feel is the stretch
periphiral arterys
muscle fibres contract or relax to change the size of the lumen controlling blood flow
the smaller the lumen the harder it is for blood to flow through
controls the amount of blood to an organ
cardiac cycle
1 heart beat - 3 stages
-atrial systole
both atria contract
-ventricular systole
both ventricles contract
-diastole
all chambers relax
myogenic
without nervous impluse
how does the heart beat
myogenic
-sinoatrial node (pacemaker) -SAN
-atrioventricular node - AVN
-purkyne tissue
-bundle of HIS
atrial systole
SAN sends impules across both atria
atria contracts
increase pressure
blood enters ventriles through atrio-ventricular valves
0.1 seconds
ventricular systole
atria relax
pressure of blood forces atrioventricular valves to close - bottom
the SAN stimulates the AVN to produce impulses
these travel down the ventricles through the bundles of HIS
The purkyne fibres pass the impulses to ventricle walls. There is a delay
this causes the ventricles to contract
opening the semi lunar valves
blood passes into the aorta and pulmonary arteries
0.3 seconds
diastole
ventricles relax
pressure in the ventricles falls below that in the arteries
blood under high pressure in the arteries cause the semi lunar valves to shut
all heart muscles relax
0.4 seconds
ecgs
electrocardiograms
record the electrcial activity in the heart
undersanding ecgs
p wave: artial systole
qrs: ventricular systole
t wave: diastole
q->t contraction (ventricles)
t->p filling time
p->q atria contracting
thromboplastin
catalyses conversion of prothrombin into thrombin
happens at the site of a wound
calcium ions need to be present
thrombin
thrombin acts on fibrinogen converting it to fibrin
this forms a mesh to cover the wound
what happens in a bood clot
cascade of events
platlets release thromboplastin
thromboplastin( catalyst) : prothrombin -> thrombin ( with calcium ions)
thrombin : fibrinogen -> fibrin
fibrin : mesh of fibres to cover wound
platlets and blood cells get caught in mesh
proteins in the platlets contract making the clot tighter and tougher
atheroscelerosis
build up of plaques on the inside of the arteries
restricts blood flow or even block it
-slight damage to cells leads to a deposit of lipids
-blood platelets form a cap over the fatty plaque which narrows the artery
-any further damage causes a clot to form and can block the whole artery
non modifyable risks of ather….
age - blood vessels loosen with age
sex -before menopause women are less likely (eostorogen reduces plaque )
genetics- more likelehood in some families
modifyable risks
lifestyle
diet-high salt increases water content of blood so high volume needs pumped so heart needs to do more work
stress- trigers chemicals that trigger a imflamatory response in the blood vessels -high blood pressure
smoking- chemicals damage the artery lining
lack of exercise- lowers blood pressure and chloesterol
high blood pressure- increases the risk of damage to the vessel
obsetity- diabetes type 2 damage to the lining of blood vessels
plasma
transports:
-digested food products from small intestine to wherever needed
-nutrient molecules from storage to wherever needed
-excretory products from cells to organs
-chemical messages
-heat
has plasma proteins which are too large to leave the blood
tissue fluid
liquid that surrounds cells
allows transport between blood and cells
removes waste
cells bathe in tissue fluid
uses
-hydrostatic pressure
-osmosis
supply glucose/salts/hormones
removes co2 and urea
hydrostatic pressure
high at the arterial end so forces fluid out
cells bathe in tissue fluid
higher water potential outside then inside so reabsorbed by osmosis and venus end
10% does not go in and joins lymphatic system
lymph
10% needs to be drained\passes through the lymphatic system and drains back into the circulatory system
contains lymphocytes -made in lymph nodes
movement is caused by the contraction of nearby muscles and valves to prevent back flow
moves in the lymphatic vessels
more fatty acids than blood
tissue
group of similar cells that form similar function
aorta compared to vein
thicker walls
narrower lumen
more muscle
semilunar valves
adaptation of red blood cells
flat so many can fit through capillaries
high surface area - vol ratio so faster absorption
biconcave nature
contains haem so can bind with oxygen
blood diseases
more white
-infectioon immune response
fewer red
-anemia
-lukemia
fewer platlets
-lukemia
-anemia
more eosionophills
-allergy
-parasitic infection
-asthma
smoking on blood clot formation
damage to endothelium lining
inflamatory response
macrophages arive
deposits of cholesterol
formation of plaque
arteries narrowed
reduced blood supply increases blood pressure
can lead to stroke/heart disease
cardiac cycle
impulse starts at SAN
takes 0.3s to AVN
atrial systole takes 0.07
delay at AVN
0.16 at bundles of his
0.17 at purkyne fibres
ventricular systole 0.22
atrioventricular valves open during atrial and close during ventricular
function of blood clot
prevent entry of pathogen
prevent blood loss
myogenic cardiac cycle
contraction from SAN
depolarisation causes atrial systole
delay at avn
depolarisation through purkyne fibres and bundles of his
ventricular systole from base of heart
similarities between single and double
contain oxygenated blood
contains blood and vessels
differences between single and double
single
-1-2 compartments of the heart
blood passes through heart once
ox and deox not separate
lower pressure
less affective
double
-3-4 compartments
blood passes through heart twice
ox and deof separate
higher pressure
atheletes
more cardiac muscle
stroke volume increases
same cardiac output with fewer beats
sufficient oxygen supply
for respiration in cells
formation of tissue fluid
oncotic pressure caused by plasma proteins
hydrostatic pressure due to heart pumping
hydro>oncot fluid forced out
oncot>hydro fluid moves in
leaves capillary through pores
double circulatory system positives
more oxygen for respiration
maintains high pressure to body
keeps oxygenates and deoxygenated blood separate
pulmonary and circulatory system separate
