transport in mammals Flashcards
single circulation
blood flows through the heart once during the course of the circulation example: fish
blood circulation in fish
why high pressured blood entering gills in fish
for exchange of gasses and after the gills it should go through all parts of the fish before reaching the heart
double circulation
blood flows through the heart twice during the course of circulation
pulmonary circulation
right ventricle -> lungs -> left atrium
systematic circulation
left ventricle -> lungs -> right atrium
Closed Circulation
blood always flows through blood vessels and never comes in direct contact with tissue
Open Circulation
Blood is pumped out of the heart in open spaces called hemocoel and tissues are always lathered in it
artery diagram
how are arteries able to withstand high pressure
made up of thick walls ( collagen + elastic fibres + SM)
collagen in arteries
provide high tensile strength to withstand high smooth fibre muscle pressure and prevent bursting of arteries
elastic fibers
stretch and recoil ( when stretched arteries dilate, more blood can flow, pressure decreases) ( when recoiled arteries constrict, pressure increases and less blood flow)
smooth muscle
contracts and relaxes - it districts the flow of blood through the arteries
elastic arteries:
large arteries with a lot of elastic fibre and less smooth muscle ( present near heart)
smooth arteries:
comparatively small arteries with more smooth muscle and less elastic fibre and next to the destination blood
how does a narrow lumen affect arteries?
help in increasing pressure
how does a circular cross-section affect arteries?
maximum volume of blood transported with maximum contact with water
how does an endothelial cell affect arteries?
provide a smooth surface and less restriction to blood flow. As the distance, from the heart increases, pressure decreases, and the thickness of the wall decreases
valves present in veins
prevents backflow of blood and makes sure blood flows in one direction
how does a large lumen affect veins?
decreases pressure and more blood flow
how does changing shape easily affect veins?
to accommodate more volume of blood
how does less elastic fiber affect veins?
pressure is low in veins so no need of stretching and recoiling
how does thin walls affect veins?
pressure is low, it allows the skeletal muscle to squeeze the veins and push the blood against gravity
in veins, there are less concentration of
collagen, elastic fibre and smooth muscle
vein diagram
capillary diagram
capillaries are __
one cell thick
capillaries are made up of
a single layer of endothelial cells for a shorter diffusion distance
presence of pores and gaps in capillaries
allows soluble molecules to leave the blood and become part of the tissue fluid
why are capillaries small in size?
bring red blood cell close to the cell- effective diffusion
why are capillaries large in number?
increases the surface area for more diffusion and reduces pressure
diameter of capillary and RBC
7 micro metre to help in effective diffusion of materials
why do capillaries have large SA:V ratio
for effective collision
pre capillary sphincter muscle
to control amount of blood flow to capilarry
In capillaries the hydrostatic pressure of blood is high
it forces molecules out of the plasma into the tissue fluid
blood is a
connective tissue
Red blood cells / Erythrocytes are produced in
bone marrow destroyed in the spleen/liver
life span of RBC
120 days
other name for RBC
Erythrocytes
when RBC is in bone marrow
the nucleus is present it helps the production of hemoglobin and carbonic anhydrase enzyme, the nucleus is broken down once enough hemoglobin and enzyme are produced
RBC shape
biconcave or disk-shape
in RBC no nucleus, so
no mitosis
in RBC no ribosome
so no protein synthesis
how is the structure of RBC adapted for its function?
- organelles absent - to accommodate more hemoglobin- more oxygen carried
- biconcave/ disc shaped- it can squeeze through the capillary, larger surface area to volume ratio- faster diffusion
- hemoglobin is arranged towards the surface- shorter diffusion distance, effective diffusion/faster diffusion
- the same diameter as that of the capillary helps in effective diffusion
-flexible- can deform so that it can pass through the capillary
2 types of WBC
phagocytes and lymphocytes
2 types of phagocytes
monocyte and neutrophil
2 types of lymphocytes
B cells and T cells
The other name of RBC
Erythrocytes
neutrophil
first, one to attack a pathogen, accumulate at the site of inflammation
forms 75% of phagocyte
neutrophil diagram
RBC diagram
monocyte and macrophages other name
antigen-presenting cells
in blood monocytes and tissues
macrophages
monocyte diagram
monocyte function
they digest the pathogen and present it on the surface so that lymphocytes can identify them
they leave the blood and surround the tissues then they called macrophages
they undergo phagocytosis and present the part of the pathogen on the cell surface membrane then it is called as antigen presenting cells
it is doing that to attract lymphocytes
immune response by a phagocytes is non specific
phagocytosis
engulf pathogen from vesicle/phagosome
they fuse with the lysosome
lysosomes releases hydrolytic enzymes and breaks the pathogen into small fragments and present them on the cell surface membrane
protease enzyme
breaks down protein to amino acids, peptide bonds broken
Carbo anhydrase enzyme
breaks down carbohydrates to glucose, glycosidic bonds broken
lipase enzyme
lipids to fatty acids + glycerol, ester bonds broken
nuclease enzyme
nucleic acids to nucleotides , phosphodiester bonds broken
neutrophil compared to monocyte
- lobed nucleus
- granules present
- smaller in size
- circulates in blood
monocyte compared to neutrophil
- bean-shaped nucleus
- granules absent
- larger in size
- settle in tissue/organ
lymphocytes function
produced in bone marrow migrate to other parts for maturation
monocyte diagram
lymphocyte diagram
Bcells
matured in bone marrow, when activated, undergo mitosis to form plasma and memory cells.
plasma cells secrete antibodies and memory cell helps in secondary immune response
Tcells
Matured in the thymus gland, it stimulates B lymphocytes to produce antibodies kill bodies own cells that are infected with pathogen
similarities between Bcells and Tcells
both produce in bone marrow
during maturation, both receive receptors that bind with specific antigens
when matured both circulate in blood, tissue fluid, and lymph
activated during an immune response due to the presence of receptors
what leaves the capillary
oxygen, glucose, amino acid, fatty acid, glycerol, ions, water
what enters the capillary
carbon dioxide and urea
plasma
pale yellow in colour contains dissolved nutrients, gases, ions etc
as blood flows through the capillary
some of the plasma components leak out through the pores in capillary wall and surrounds the tissue forming the tissue fluid
tissue fluid
=plasma - (plasma protein + RBC)
no plasma protein or RBC leaves the capillary
as they are too large to escape, WBCs can leave the capillary as they can change their shape
Tissue fluid contains
proteins produced by the tissues and given out to the tissue by exocytosis. it also contains antibodies secreted by B-lymphocytes. plasma protein inside the capillary decreases the water potential so water re-enters the capillary by osmosis. if protein diffuses out of the capillary into the tissue fluid more water is accumulated resulting in oedema
people with kwashiorkor have
fewer proteins in the blood so water potential does not decrease much and water is accumulated in tissues
partial pressure
the pressure exerted independently by a particular gas in a mixture of gases
oxygen + hemoglobin reaction
oxygen dissociation curves show
the affinity of hemoglobin for oxygen. it determines the percentage saturation of haemoglobin with oxygen
carbon monoxide, oxygen and hydrogen ions share the
same binding site ( binds to haem group)
carbon dioxide binds to the
protein chain
cooperative binding
binding of one oxygen molecule helps the binding of other oxygen molecules easier
hemoglobin is an
allosteric protein as it has multiple binding sites (4)
why dissociation curve is sigmoid?
due to the way in which oxygen molecules bind with hemoglobin. first oxygen molecule binds with difficulty as it is not able to locate the haem group, with difficulty it binds once it binds with oxygen hemoglobin and changes its shape, as a result of these changes 2 oxygen molecules are taken up easily and the curve rises steeply bringing 75% saturation. its hard for the last oxygen molecule to bind due to lack of space. over the steep part of curve, a small decrease in partial pressure causes a large fall in the percentage saturation
Difficulty of binding
1 4 2 3 ( decreasing order)
P50
Partial pressure of oxygen at which 50% saturation is achieved
curve for alveoli and tissue
curve is shifted towards left
haemoglobin has a higher affinity for oxygen
more of association takes place
curve is shifted towards right
haemoglobin has a lower affinity for oxygen , more of disassociation takes place
factors that shift curve towards right
- excercise
- high CO2 concentration
- low pH of blood
- high temperature
factors that shift curve towards left
- rest
- low CO2 concentration
- high pH of blood
- low temperature
Birds and human
activity level of bird is high, so it requires more energy, increases rate of respiration, more carbon dioxide produced, curve shifts towards right, haemoglobin has less affinity, more dissasociation
foetal haemoglobin vs adult haemoglobin
lungs is not functional, it recieves oxygen by diffusion through placenta, partial pressure of oxygen is low, mother haemoglobin releases some oxygen which diffuses into the foetus blood shifting the curve towards left, more affinity, more association
lungworm
lungworm lives in burrow where partial pressure of oxygen is low, shifts the curve towards left, more affinity, more association
Lama
Lama lives inh altitude, partial pressure of oxygen is low, shifts the curve towards left, more addinity , more association
Rat vs elephant
activity level of rat is high, so it requires more energy, increased rate of respiration, more carbon dioxide produced, curve shifts towards right, haemoglobin has less affinity, more dissociation
haemoglobin vs myoglobin
myoglobin contains one polypetide chain so one haem group, therefore carry one molecule of oxygen. it is present in skeletal muscle and cardiac muscle.
Myoglobin has a very high affinity for oxygen, oxyhaemoglobin is stable and it releases oxygen only when partial pressure is very low. No cooperative binding and its not an allosteric protein
carbon dioxide
at high carbon dioxide concentration haemoglobin affinity decreases curve shifted towards right, more dissociation
carbon monoxide
carboxyhaemoglobin is very stable, high affinity, shifts the curve towards left, leading to hypoxia (lower oxygen concentration is blood) it can be treated by exposing a mixture of oxygen and carbon dioxide. it stimulates the respiratory centre of medulla and increases breathing rate
activity increases
affinity decreases, dissociation increases shifts the curve to the right
activity decrease
affinity increases, dissociation decreases shifts the curve to the left
bohrs effect explains
the effect of carbon dioxide and hydrogen ions on haemoglobin affinity for oxygen
In bohrs effect,
Partial pressure of carbon dioxide is high in tissues, so CO2 diffuses out of the tissue into the red blood cell. it binds with water to form carbonic acid ( H2CO3) . it is catalysed by the enzyme carbonic anhydrase, it is a fast and reversible reaction. H2CO3 is unstable and it dissociates to give H+ and HCO3- ions. haemoglobin has a higher affinity for H+ when PO2 is low. oxyhaemoglobin breaks to give oxygen and haemoglobin. haemoglobin binds with H+ yo form haemoglobinic acid (HHb). oxygen molecule diffuses inside the tissue. HCO3- produced from carbonic acid leaves the RBC and moves to the plasma. Cl- enters inside the RBC to maintain electrical neutrality. this process is called as a chloride shift.Some of the CO2 molecule can directly bind with haemoglobin to come Carbaminohaemoglobin (HbCO2)
Haldane effect
heart is myogenic
can generate the impulse by itself, heartbeat is not under the direct control of the nervous system
Sinoatrial node AKA
SA node
Sinoatrial node
present in right atrium near the opening of vena cava. SAN initiates the wave of excitation as electrical impulse. wave of excitation then spreads to the left atrium with help of conducting tissues. as a result of this, atrium contracts.
Total duration is 0.1s
non conducting fibre/ fibrous ring prevents the impulse from reaching the ventricles
atrioventicular node AKA
AVN
Atrio venticular node
Av node delays the impulse by 0.1s, this prevents atrium and ventricle contracting simultaneously and ensure the movement of blood in the right direction
This time delay allows atria to get empty and undergo complete contraction. from AV node the wave of excitation is carried by bundle of his. which split into minor branches called purkyne tissue/fibre.
it is highly branched in left ventricle as it has more muscle and each muscle should receive the impulse
purkyne tissue conduct the wave of excitation form the base of the ventricle upward resulting in the contraction of the ventricle.it forces the blood to move from the base of the ventricle to the corresponding artery
functions of SA node
acts a pace maker, regulates heartbeat, releases wave of excitation, helps in atrial systole, initiates heart beat/cardiac cycle
functions of AV node
delays the impulse by 0.1s passes the impulse to the bundle of his/purkyne tissue, allows atrial systole to compete before ventricular systole
functions of purkyne tissue
conduct impulse to base/apex of heart/ septum/ ventricles so that the papillary muscle contract and close the atrioventricular valve
cardiac cycle 3 parts
artrial systole -0.1s
ventricle systole - 0.3s
joint diastole -0.4s
why do we need a transport system
- to transport oxygen from the lungs to all body parts
- to transport hormones from endocrine glands to target organs
- to transport digested food from the alimentary canal to the different body parts
- to transport the waste products of metabolism from the cells to the organ of excretion
why do we need a transport system while microorganisms do not
- they have a high surface area to volume ratio so they can obtain their requirement and get rid of their wastes through their surface area while we gave a relatively small surface area to volume ratio
- in microorganism, internal transport from one cell to another can take place by diffusion or active transport because the distance between the different parts of the body are extremely small
factors which determine the need for a transport system
- the surface area to volume ratio is bing
- the distance over which materials have to be transported are very large
- if the organism is metabolically very active so it requires a rapid supply of nutrients and oxygen and a rapid removal of large amount od waste products
similarities between blood vessels
all are tubular, endothelium present, transports blood
arteries compared to veins and capillaries
veins compared to arteries and capillaries
capillaries compared to arteries and veins
function of elastic fibre
allows expansion of the lumen without casting damage, it keeps the pressure high by the elastic recoil mechanism and smooths out the flow of blood
in elastic fibers - largest arteries
lots of elastic fibre to cope with high pressure
in elastic fibers- small arterioles
little elastic fibre as pressure is less
function of smooth muscle
this muscle can contract and narrow arterioles by vasoconstriction so reducing blood flow. this muscle can relax and widens arterioles by vasodilation so increasing blood flow and controlling the distribution of blood
smooth muscle in largest arteries
little smooth muscle as lumen is too large to clos
smooth muscle in small arterioles
lots of smooth muscle to control blood flow by vasoconstriction
collagen function
this fibrous protein provides strength to stop arteries bursting when the pressure is high
collagen in the largest arteries
lots of colllagen to give strength to prevent bursting
collagen is small arterioles
little collagen as pressure is low and so less strength needed
tissue
collection of one or more types of cell, specialised to carry out a particular function
an organ can be considered a structural unit within an organism that
consists of more than one type of tissue
performs a particular function
the chordae tendinar are
chord like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart
papillary muscles are located in
the ventricles of the heart
stroke volume
amount of blood given out of the heart in a beat (70ml)
stroke output
amount of blood given out of the heart in a minute
cardiac output
heart rate * stroke volume
order of pressure
arteries -> arterioles -> capillaries -> venules -> veins
Explain, with reference to function, the difference in the thickness of muscle of the left and right ventricle.
The left ventricle pumps blood to rest of the body and the right ventricle pumps blood to the lungs
Right ventricle has smaller muscles because travel is short distance
Less resistance
Less force/pressure required
Explain why the mammalian circulatory system is described as close double circulation.
Double – blood passe *s through the heart twice during one circulation;
Closed – blood travels inside blood vessels
Disadvantage of having no nuclei in RBCs:
- Cannot carry out, protein synthesis/replication/repair;
- Short life span;
- Cannot, divide/replace themselves.
Explain how the structure of red blood cells is suited to their function of transporting oxygen to body tissues.
- small size / 6-8 μm (diameter), to squeeze through capillaries (7 μm) ;
- small size / 6-8 μm (diameter), so, haemoglobin (molecules) near to surface (of plasma membrane) / reduces distance for diffusion (in / out of rbc) ;
- no nucleus / lack of organelles, so more room for haemoglobin (so more oxygen transported) ; R more room for oxygen
- biconcave shape / diagram drawn, increases surface area for, diffusion / uptake / release (of oxygen) ;
- flexible / AW ( membrane), to squeeze through capillaries ;
Explain how heart action is initiated and controlled (reference should be made to the sinoatrial node, the atrioventricular node and the Purkyne tissue).
- myogenic;
- SAN, is pacemaker / sends out impulses / waves of excitation / initiates, heartbeat / action potential / contraction; R electrical, messages / waves / signals
- AVN delays, impulse / contraction (of ventricles);
- detail e.g. specific time ref (0.1 - 0.2 secs) or to allow ventricles to fill / atria to empty;
- relays impulse to Purkyne tissue / bundle of His;
- Purkyne tissue conducts (impulse) to base / apex of heart / septum/ ventricles;
- ref to papillary muscles contracting;
- ventricle (muscle) contracts / ventricular, contraction / systole, from base upwards;
- (blood) into arteries / named artery;
Explain how the structure of haemoglobin aids the uptake of oxygen in the lungs.
- 4 polypeptides/4 globins/4 amino acid chains;
- outwardly pointing hydrophilic (R) groups, maintain solubility/AW;
- each with a haem group;
- ref to iron/Fe2+ ( ion); R Fe3+/iron atom
- temporary attachment to oxygen; A readily attaches/binds combines with
R oxygen binds to haem - 4 molecules of oxygen; A 4 O2/8 oxygen atoms R 4 oxygens unqualified
- oxyhaemoglobin; A HbO8
- ref to cooperative binding;
Explain how CO2 stimulates the release of oxygen from the blood.
- carbon dioxide reacts with water to form carbonic acid;
- catalysed by carbonic anhydrase;
- dissociates to hydrogen carbonate and hydrogen ions;
- hydrogen ions combine with haemoglobin; R hydrogen ions replace oxygen in haemoglobin
- forms haemoglobinic acid/HHb;
- so releasing oxygen;
ignore ref to Bohr shift (question says ‘explain’)
A from equations.
Transport of CO2
Describe and explain how carbon dioxide (CO2) and hydrogen ions (H+) play a role in the unloading of oxygen from haemoglobin.
- diffusion of, carbon dioxide / CO2;
- into red blood cell from correct source ;
- description of carbonic acid formation followed by H+ production ;
- ref. carbonic anhydrase ) fast reaction; A ecf from (d)
- haemoglobin has a higher affinity for hydrogen ions than oxygen ; A haemoglobin releases oxygen more easily in acidic conditions accept idea of H+ binding to haemoglobin bringing out oxygen release
- ref. to, allosteric effect / change in tertiary structure / AW, in (oxy)haemoglobin, causes, release / AW, of oxygen ;
- formation of haemoglobinic acid ; must refer to, H+ binding / decreased pH
- ref. higher partial pressures / AW, CO2, linked to (oxy)haemoglobin releasing, more oxygen / oxygen more readily ; Bohr shift
- formation of carbamino-haemoglobin ; R carboxyhaemoglobin
- chloride shift, qualified ;
e.g. as hydrogen carbonate ions move out of cell, chloride ions move in e.g. to maintain, electroneutrality / a balance of charge / ions ;
Composition of blood at venule end, compared to that at the arteriole end
Blood at venule end has:
less pressure ; A low pressure
less oxygen ; A deoxygenated
less glucose ; only accept more glucose if identified as liver
fewer / more, amino acids / fatty acids ;
less water / lower water potential / lower solute potential / higher osmotic pressure / higher
concentration of solutes and / or rbcs ;
A ‘blood is more concentrated’
fewer ions ;
more of named cell product ; e.g. insulin / glucagon / albumen / AW
(more), urea / excretory waste ; R waste unqualified
The percentage saturation of haemoglobin with oxygen decreases as the partial pressure of carbon dioxide increases. Explain how this happens.
- hydrogen ions / protons ; A H+
- either
react or combine with haemoglobin / form haemoglobinic acid / form HHb ; A ‘picks up’ / absorb
or
carbon dioxide combines with haemoglobin / forms carboxyhaemoglobin ; - (so) stimulate haemoglobin to release more oxygen (in areas of low pO2) ;
ref. to, allosteric effect / change in tertiary or quaternary structure or shape ; A conformational change - either
haemoglobin has a higher affinity for hydrogen ions than oxygen = 2 marks
or
haemoglobin has a higher affinity for carbon dioxide than oxygen = 2 marks
blood vs tissue fluid
