cardiovascular and respiratory systems (should be in OP4103) Flashcards
what does malignant hypertension look like in the retina?
you could see hard exudates and disc swelling
what are the two parts of the circulatory system?
-pulmonary circulation where blood is carried between the lungs and the heart
-systemic circulation where blood is carried between the heart and the rest of the body
what are the functions of the cardiovascular system?
-links external environment to tissues
-distributes essential metabolites
-removes metabolic waste such as co2 from tissues
-circulates hormones of endocrine system
-distributes heat to maintain body temp
-transports blood coagulation factors
-transports cells and antibodies
what are the three layers of the heart?
-endocardium: thin layer of endothelium
-myocardium: cardiac muscle
-epicardium: thin external membrane
in the heart, what are branching muscle cells?
cells in the cardiac muscle (myocardium) that form intercalating disks that are synctium and in continuous cycle
Give the sequence of blood from the lungs and back to the lungs
From the lungs it goes to the
1. Pulmonary vein
2. Left atrium
3. Left ventricle
4. Aorta
5. Rest of the body
6. Vena cava
7. Right atrium
8. Right ventricle
9. Pulmonary artery
And back to the lungs
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What side of the heart deals with oxygenated and deoxygenated blood respectively
right deoxygenated and left oxygenated
What are the two types of atrioventricular valves and where are they each found?
- tricuspid valve found between the right atrium and ventricle
- bicuspid valve found between the left atrium and ventricle
What do the semi lunar valves do?
Prevent back-flow of blood from aorta into the ventricles
Name the vessels which are connected to the four chambers of the heart and what they do
aorta connected to the left ventricle and carries oxygenated blood to all parts of the body except for the lungs
- the vena cava is connected to the right atrium and brings deoxygenated blood back from the tissue of the body (except the lungs)
- the pulmonary artery is connected to the right ventricle and carries deoxygenated blood to the lungs where is oxygen is replenished and co2 removed
- the pulmonary vein is connected to the left atrium and carries oxygenated blood into the heart from the lungs
For atrial systole,
What is it?
What does it cause to happen to:
-the volume of the atria
-the pressure of the atria
-the volume of the ventricles
-the pressure of the ventricles?
it’s when the atria contacts
- volume of atria decreases
- pressure in the the atria increases
- volume of the ventricles increases
- pressure in the ventricles decreases
For ventricle systole,
What is it? What does it cause to happen to: -the volume of the atria -the pressure of the atria -the volume of the ventricles -the pressure of the ventricles?
It’s when the ventricle contracts
- volume of atria has no change
- pressure in the atria has no change
- volume of ventricles decreases
- pressure in ventricles increases
For diástole,
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What is it?
What does it cause to happen to:
-the volume of the atria
-the pressure of the atria
-the volume of the ventricles
-the pressure of the ventricles?
When both chambers relax and the heart fills with blood
- Volume of the atria increases
- pressure of the atria increases
- volume of the ventricles slowly increases
- pressure of the ventricles slowly increases
What causes valves to open or to close?
When there’s differences in pressure between the compartments
In a chamber, when is high pressure achieved?
When the chamber fills with blood as the muscles of the chamber walls contract decreasing the volume
When do the atrioventricular valves close?
When the pressure in the ventricle is greater than the pressure in the atria
Where are atrioventricular valves located, what do they do and why is this useful?
Located between the atrium and ventricle and right atrium and ventricle
- they close to prevent back flow of blood when contraction of ventricles means ventricular pressure exceeds atrial pressure
- the closure allows blood to move into the aorta and pulmonary artery from the ventricles when they contract rather than back into the atria
Where are the semi lunar valves located, what do they do and when do they do this?
- found in the aorta and pulmonary artery
- close to prevent back flow of blood into the ventricles when pressure in the pulmonary artery and aorta exceeds that of the ventricles
- this happens when the elastic walls of the vessels recoil increasing the pressure within them and when the ventricle walls relax which reduces the pressure within them
What is the function of arteries?
To transport blood rapidly under high pressure from the heart to the tissues (the blood is therefor oxygenated in most cases)
What do arterioles do?
They carry blood under lower pressure than the arteries from arteries to capillaries and control the flow of blood between the two
What do veins do?
They transport blood slowly under low pressure from capillaries in the tissue to the heart
What do capillaries do?
They exchange metabolic materials such as oxygen, carbon dioxide and glucose between the blood and cells and the flow of the blood is very slow to allow time for the exchange of materials
Give 4 structural features of veins
The muscle layer is relatively thin
- the elastic layer is relatively thin
- the overall thickness of the wall is small
- there are valves at intervals throughout
Give 2 structural features of arterioles compared to arteries
their muscle layer is relatively thicker than in arteries
Give four structural features of arteries
- the muscle layer is thick compared to veins
- the elastic layer is relatively tho just compared to veins
- the overall thickness of the wall is great
- there are no valves
Give 5 structural features of capillaries and how this allows them to be good gas exchange surfaces
- The endothelium is only one cell thick so this allows for a shorter diffusion distance
- they are numerous and highly branched which provides a larger surface area for gas exchange
- they have a narrow diameter so they can easily penetrate all tissues
- they have a narrow lumen causing the red blood cells to be squeezed against the sides of the capillary wall bringing them even closer to the cells and reducing the diffusion distance
- they have fenestrations (tiny holes) which allow white blood cells and fluid to move in and out in order to fight infections and exchange materials within cells
In arteries how is the fact that the muscle layer is thick compared to veins allow them to carry out their function?
As it means smaller arteries can be constricted and dilated in order to control the blood passing through them.
In arteries how is the fact that the elastic layer is relatively thick compared to veins allow them to carry out their function?
As with the high pressure of the blood, the wall stretches and relaxes with the hearts systole and diastole which helps to maintain the high pressure and smooth pressure surges
In arteries how is the fact that the overall thickness of the wall is large allow them to carry out their function?
To resist the vessel from bursting under pressure
In arteries, why is there no valves?
As the blood is under constant high pressure from the heart so it’s unlikely to flow backwards
In arterioles, why is the muscle layer relatively thicker than in arteries?
Because the muscle layer contracts allowing the lumen of the arteriole to constrict which restricts the flow of blood so controlling its movement into the capillaries
In arterioles, why is the elastic layer relatively thinner than in arteries?
Because blood pressure is lower
In veins, why is the muscle layer relatively thin?
Veins carry blood away from tissues and so their constriction and dilation can’t control flow of blood to the tissue
In veins, why is the elastic layer relatively thin?
As the pressure is too low to create a risk of bursting and the thinness allows them to be flattened easily aiding the flow of blood
In veins, why is the overall thickness of the wall small?
The low pressure of blood in the veins doesn’t cause them to burst and the pressure is too low to create a recoil action
In veins, why are their valves at intervals throughout?
The pressure is very low and when body muscles contract, veins are compressed which pressurises the blood within them and so valves ensure pressure directs the blood in one direction only
give the passage of air to the lungs
- trachea
- bronchus
- bronchioles
- alveoli
how are the bronchi specialised?
they have cilia which consist of mucous coated membranes to catch dirt particles and move the mucous laden dirt to the throat
what layers do alveoli consist of?
a single layer of simple squamous epithelium
What is inspiration?
When the air is forced into the lungs because the air pressure of the atmosphere is greater than that in the lungs
What is expiration?
When the air is forced out of the lungs because the air pressure of the atmosphere is less than the air pressure in the lungs
What three muscles cause pressure changes in the lungs?
- The diaphragm
- external intercostal muscles
- internal intercostal muscles
Go through the process of inspiration in terms of the muscles involved
- The external intercostal muscles contract while the internal intercostal muscles relax
- The ribs are pulled upwards and outwards increasing the volume of the thorax
- The diaphragm muscles contract causing it to flatten increasing the volume of the thorax
- The increased volume of the thorax results in reduced pressure in the lungs
- Atmospheric pressure is now greater than pulmonary pressure so air is forced into the lungs
Go through the process of expiration in terms of the muscles involved
- The internal intercostal muscles contract while the external intercostal muscles relax
- The ribs move downwards and inwards decreasing the volume of the thorax
- The diaphragm muscles relax so it’s pushed up again by the contents of the abdomen that were compressed during respiration and so the volume of the thorax is further decreased
- The decreased volume of the thorax increases the pressure in the lungs
- The pulmonary pressure is now greater than that of the atmosphere so air is forced out of the lungs
Give 6 reasons why diffusion between the alveolar and the blood is very rapid
- Because the very narrow capillary that surround the alveoli means red blood cells are slowed down as they pass through pulmonary capillaries and so allowing more time for diffusion
- the distance between the alveolar air and the red blood cells is reduced as the red blood cells are flattened against the capillary walls
- the walls of both alveoli and capillaries are very thin and therefor the distance over which diffusion takes place is very short
- alveoli and pulmonary capillaries have a very large total surface area
- breathing movements constantly ventilate the lungs and the action of the heart constantly circulates blood around the alveoli, ensuring a steeply concentration gradient of gases to be exchanged is maintained
- blood flow through the pulmonary capillaries maintains a concentration gradient
Why is the alveolar surface moist?
Because this helps to dissolve gases helping them to diffuse p across the gas exchange surface more efficiently
what part of haemoglobin does oxygen bind to?
Fe of haem group
what part of haemoglobin does co2 bind to?
binds to the amine groups of the amino acids of the polypeptides
Give the steps that take place following the loading, transport and unloading of oxygen
- At the gas exchange surface, carbon dioxide is constantly being removed
- The pH is slightly raised due to the low concentration of C02
- The higher pH changes the shape of the Hb into one that enables it to load oxygen more readily
- This shape also increases the affinity of haemoglobin for oxygen so it’s not released while being transported in the blood to the tissues
- In the tissues, co2 is produced by respiring cells and this is acidic so the pH of the blood within the tissues is lowered
- The lower pH changes the shape of the haemoglobin into one with a lower affinity for oxygen and so it releases its oxygen into respiring tissues
How does the Bohr effect explain the behaviour of Hb in gas in rapidly respiring tissues?
as here, the concentration of co2 is high and the affinity of haemoglobin for oxygen is reduced so oxygen is readily unloaded from the haemoglobin into the muscle cells and so the oxygen dissociation curve shifts to the right due to the increase in oxygen
Why does a greater concentration of carbon dioxide cause haemoglobin to release its oxygen more readily?
Because dissolved carbon dioxide is acidic and the low pH causes the Hb to change shape
How does the Bohr effect explain the behaviour of Hb in gas exchange surfaces?
Because in gas exchange surfaces, the concentration of co2 is low and oxygen is high so the affinity of Hb for oxygen is increased which means oxygen is readily loaded by Hb so the reduced co2 concentration means the oxygen dissociation curve is shifted to the left
In the oxygen dissociation curve, what does it mean if:
- the graph is shifted to the left?
- the graph is shifted to the right?
- There is a greater affinity of Hb for oxygen so it loads oxygen readily but it unloads it less easily
- there is a lower affinity of Hb for oxygen so it loads oxygen less readily but it unloads it more easily
