circulatory systems Flashcards
what is the function of haemoglobin
co transportation of oxygen and carbon dioxide through the blood stream
Readily associate with oxygen at the surface where gas exchange occurs and readily dissociate from oxygen at respiring tissues
What is the function of blood?
Carry substances around the body
What are the features of haemoglobin?
It is a protein found in an erythrocyte
It is made up of four polypeptide chains
It is a quaternary protein
Each chain is associated with a haem group
It contains an iron ion
Can carry four oxygen molecules at a time (fully saturated)
What is the process of oxygen transportation?
Haemoglobin transport oxygen from the lungs to respiring tissues
Including picking up oxygen at lungs (loading)
Transporting
Dropping oxygen off at tissues ( unloading)
Why is carbon monoxide dangerous?
It takes the place of oxygen in haemoglobin as it is easier to bind making it harder to get oxygen to respiring tissue in the lungs
What does fully saturated mean?
Haemoglobin is bound to 4 oxygen molecules forming Oxy haemoglobin
What are the two contradictory jobs of haemoglobin?
Loading oxygen at lungs
Unloading oxygen at respiring tissues
Why can’t we do both loading and unloading of oxygen at the same time?
Oxygen partial pressure
Shape of haemoglobin
Carbon dioxide partial pressure
PH
Temperature
What is partial pressure a measure of?
It’s a way of measuring the proportion of a mixture of gases that are specific gas occupies similar to concentration
Give an example of low partial pressure of oxygen
Respiring cells using oxygen and producing carbon dioxide
Is respiring cell use oxygen and produce carbon dioxide an example of low or high partial pressure of oxygen?
Low
Give an example of high partial pressure of oxygen
Site of alveoli
When is is partial pressure of oxygen higher
When there is a higher affinity of haemoglobin for oxygen so oxygen loads easier
When is partial pressure of oxygen lower?
When there is a low affinity of haemoglobin for oxygen so oxygen unloads easier
How does the saturation of haemoglobin affect the affinity for oxygen?
When there is a high affinity for oxygen, one oxygen loads with difficulty so haemoglobin changes shape and makes it easier for oxygen to bind
More oxygen binds and haemoglobin becomes more saturated, losing affinity
What happens during the Bohr effect
Carbon dioxide is loaded onto haemoglobin as oxygen is unloaded,
More oxygen is readily loaded into respiring tissue
How does the partial pressure of carbon dioxide affect affinity of haemoglobin at high partial pressure of oxygen
Low partials pressure of carbon dioxide= haemoglobin has a higher affinity for oxygen meaning it loads easier
Higher partial pressure of carbon dioxide=
Haemoglobin has a lower affinity for oxygen so it unloads easier
If there is a higher affinity for carbon dioxide , which way it does the curve shift on a graph
Left
If hemiglobin has a low affinity for carbon dioxide which way does the curve shift on a graph?
Right
If there is a high oxygen demand in the body, is there a low or a high affinity?
Low affinity as oxygen is unloaded at respiring tissues easier
If there is a higher affinity for oxygen, which way does it shift on the graph?
Left- oxygen is easy to load
If there was a lower affinity for oxygen which way does the curve shift on the graph?
Right- oxygen easy to unload
Give an example of an organism to show the partial pressure of oxygen and saturation of haemoglobin on the graph
Lugworm-
They are not active, live in sand burrows, and have low oxygen availability
The curve shifts to the left as there is a low partial pressure of oxygen and a higher affinity
Do smaller organisms have a small metabolic rate?
Yes
They have a high oxygen affinity
Give an example of an animal with a low affinity for oxygen
Llama
They are at a high altitude with low oxygen availability the curve shifts to the left as they have a higher affinity so oxygen is easier to load at a low partial pressure
If there is a shift to the right, is it lower or higher oxygen affinity?
Lower affinity for oxygen
If the curve shifts to the left is there a higher or a lower affinity for oxygen?
Higher affinity for oxygen
Easier to Load
How does carbon dioxide partial pressure affect the blood?
It makes blood more acidic meaning oxygen unloads easier
Describe and explain the effect of increase in carbon dioxide partial pressure on the dissociation curve of oxyhaemoglobin (fully saturated haemoglobin)
Increase in carbon dioxide= more oxygen unloading due to lots of respiration
Decrease in pH = more carbon dioxide= oxygen unloads more as blood is acidic
Decrease in carbon dioxide = more oxygen loading and less oxygen unloading
What happens when carbon dioxide partial pressure increases?
Haemoglobin affinity for oxygen decreases so oxygen is unloaded more and dissociation curve shifts to the right
When there is a decrease in carbon dioxide, partial pressure, what happens?
Haemoglobin affinity for oxygen increases so oxygen loads more and dissociation curve shifts to the left
What happens when carbon dioxide is produced it respiring tissue after respiration?
It diffuses from the cell to the plasma and then to the red blood cell
Carbon dioxide react with water to produce carbonic acid , make blood more acidic so oxygen unloads more
Describe the bohr effect- how a highly respiring tissue gets oxygen from Bohr shift
Tissue is respiring at a high rate
Producing lots of carbon dioxide
This react with water to produce hydrogen ions and carbonate ions
The hydrogen ions cause a change in the shape of haemoglobin reducing its affinity for oxygen
Causing oxygen to unload easier from haemoglobin
This means oxygen is available for the tissue to keep inspiring at a high rate
What is the role of haemoglobin in supplying oxygen for tissues of the body?
Loads oxygen areas of high partial pressure for example the alveoli
Unload oxygen at areas of lower partial pressure for example respiring tissues
What is the advantage of the oxygen dissociation curve for haemoglobin shifting to the right during excercise
There is a lower affinity for oxygen
Oxygen is harder to load and easier to unload
More oxygen goes to respiring tissues
Oxygen binds to glucose to produce ATP for energy release and more rapid respiration
Lower affinity for oxygen
Shift to right
Unloads oxygen easier at respiring tissues
Higher affinity
Shift to left
Oxygen is easier to load
What is the name for the process of which haemoglobin binds to oxygen?
Loading- happens in the lungs
What is the name of the process of which haemoglobin releases oxygen?
Unloading- happens at tissues
Pathway of blood through the heart
- Vena cava vein (right)
- Right atrium
- Atrioventricular valve (right)
- Right ventricle
- Semi- lunar valve (right)
- Pulmonary artery
- Lungs
- Pulmonary vein
- Left atrium
- Atrioventricular valve (left)
- Left ventricle
- Semi-lunar valve (left)
- Aorta
- Body
Direction of blood flowing in an artery
Away from heart
Direction of blood in a vein
Into the heart
Why does blood go to in the vena cava?
From the body to the heart
Why does blood go to in the pulmonary artery?
Leaves heart and goes to lungs to load oxygen
Why does blood go to in the pulmonary vein?
From lungs, into heart
Where does blood go to in the aorta?
Leaves heart, goes around body to unload oxygen at tissue
Why is the left side of the heart thicker?
Pumped blood all around the body and needs higher pressure and more muscle
Why is the maximum pressure in the ventricle higher than in the atrium?
Ventricles have a thicker muscular tissue to deal with high blood pressure as contractions are stronger to push blood further
What is the function of an artery?
Carry blood away from the heart under high blood pressure
What are the adaptations of an artery?
Have a large lumen, lots of thick elastic muscle tissue, high-pressure of blood
What is the function of a vein?
Carry blood towards the heart at a lower blood pressure
What are the adaptations of a vein?
Have thinner tissue walls
Lower pressure of blood
Larger lumen
Valves
What is the function of a capillary?
Exchange of substances from cells
What are the adaptations of capillaries?
They are very thin, only one cell thick
Quick diffusion pathway
Large lumen
Permeable
What is an arteriole?
When arteries divide into smaller tubes
What is the cardiac cycle?
A sequence of cardiac contractions (systole) and relaxations (diastole)
Describe the cardiac cycle process
The heart begins in a relaxed state (diastole)
Blood passively flows into the atria, increasing blood pressure in the atria.
When the pressure in the atria exceeds pressure in the ventricles, the atrioventricular valve opens and passively flows into ventricles.
The atria then contract (atrial systole) forcing more blood to enter the ventricles
The ventricles then contract (ventricular systole), increase the pressure in the ventricles and causing the atrioventricular valves to close
Pressure in the ventricles rises , when it exceeds The pressure in the artery the semi-Lunar valve opens and blood leaves the ventricle
The ventricle relaxes and the pressure in the ventricle falls, when it falls below the pressure in the artery the semilunar valve closes to stop blood flowing backwards
When is the atrioventricular valve closed?
At high pressure in the ventricle so blood does not flow backwards into the atrium
When is atrioventricular valve open?
High-pressure in the atrium
How does blood move in One Direction through the heart?
Vans have valves to prevent the backflow of blood in the pressure gradient goes from high to low pressure
Equation for the volume of blood pumped out of the heart by one ventricle in one minute
Cardiac output (dm^3 / min) =
Heart rate (bpm) x stroke volume (dm^3/ beat)
What are blood vessels and example of?
Organs as they are made from the same tissues but different proportions relative to their functions
Describe and explain the muscle layer In an artery
Thicker so the artery can be constricted and dilated to control blood flow into arterioles
Describes and explain the muscle layer in an arteriole
Very thick so the artery can be constricted and dialated to control blood flow into capillaries
Describe and explain the muscle layer in a capillary
None- remain thin for diffusion
Describe and explain the muscle layer in a vein
Thinner- vein does not need to constrict and dilate to control blood flow
Describe the elastic layer in an artery
Thicker to allow stretching and recoil to maintain high blood pressure
Describe and explain the elastic layer in an arteriole
Thinner as blood pressure is lower than in arteries
Describe and explain the elastic layer in a capillary
None to remain thin for diffusion
Describe and explain the elastic layer in a vein
Very thin, blood pressure in veins is low
Describe and explain the tough outer layer in an artery
Thicker- resist high-pressure and prevent bursting
Describe and explain the tough outer layer in an arteriole
Thinner as blood pressure is low enough to prevent bursting
Describe and explain the tough outer layer in a capillary
None- remain thin. For diffusion
Describe and explain the tough outer layer in a vein
Thinner-pressure is low enough to prevent bursting
Why do arteries not have valves?
Blood is at a high enough pressure to prevent backflow
Why do arterioles not have valves
Blood is at a high enough pressure to prevent backflow
Why do capillaries not have valves?
Blood is out high enough pressure to prevent backflow
Why do veins have pocket valves?
To ensure that blood is flowing in one direction and pressure is very low in veins
Describe the lumen of each blood vessel
Artery- large
Arteriole- large
Vein- very large
Capillary- narrow
Why is the lumen of a capillary very narrow?
Forces red blood cells to squeeze flat against the capillary walls and reduce diffusion distance for oxygen
what is the main feature of capillaries specific for gas exchange and tissue fluid formation
permeable- substances can move out of capillaries as they are slightly leaky and have holes
why are capillaries “permeable”
holes are big enough for molecules like water glucose and oxygen to move out but large molecules like whole cells or plasma proteins can’t (slightly leaky)
what is tissue fluid?
tissue fluid is composed of plasma (95% water) and many substances are dissolved in it. as blood passes through capillaries some plasma leaks out due to high blood pressure to surrounded cells of the body
what is the advantage of water being a solute in plasma
can carry dissolved substances such as glucose and oxygen which form tissue fluid
where is tissue fluid found outside of the circulatory system and why is that important
tissue fluid bathes almost all of the cells of the body for exchange of substances between cells and blood
how do gases diffuse into capillaries
they are dissolved in the tissue fluid surrounding the cells and diffuse into the blood
what are the 2 factors which the formation of tissue fluid relies on?
hydrostatic (blood) pressure
water potential
how does hydrostatic pressure contribute to tissue fluid formation
the pressure is created when the heart muscles contract, this pressure decreases as blood gets further from the heart- caused by ventricular action. this causes plasma to be forced out of capillaries
how does water potential contribute to the formation of tissue fluid?
it is caused by the relative amounts of water and solutes, water from an area of less negative water potential (arteriole end) to an area of more negative water potential (venule end) so tissue fluid reenters
describe the role of the heart in the formation of tissue fluid
net movement of plasma out of the capillaries is caused by ventricular contraction causing the high hydrostatic pressure gradient, forcing water and dissolved substances out of permeable capillaries, forming tissue fluid
how is water from the tissue fluid is returned to the circulatory system
water leaves the capillary, proteins remain
the water potential is lower at the venule end. the fluid loss causes an increase in concentration of plasma proteins, allowing water to re enter via osmosis at the venule end as water potential is more negative. excess tissue fluid is returned via lymphatic system
why is water potential more negative at the venule end of the capillary than the arteriole
water has left the capillary so there is an increase in plasma proteins which are too large to leave, so water potential is more negative inside the capillary towards the venule end
what is tissue fluid
fluid that surrounds the cells in tissues
what is tissue fluids composed of
small molecules that are dissolved in and leave the blood plasma such as oxygen glucose and water
describe the other pathway that tissue fluid takes to return to the circulatory system
if there is excess tissue fluid, it is drained into the lymphatic system which transports it in vessels from the tissues and to a group of veins near the heart
