Edexcel (SNAB) A level biology: atherosclerosis and blood clotting (topic 1)
Summary
TLDRThis script discusses cardiovascular diseases, focusing on atherosclerosis and blood clotting. It explains how endothelium damage leads to inflammation and white blood cells absorbing LDLs, forming atherosclerotic plaques that narrow blood vessels. This narrowing impedes blood flow, reducing oxygen and nutrient delivery, and impairing waste removal, leading to cellular dysfunction and tissue death. Blood clotting, another issue, can obstruct arteries, further reducing blood flow and causing similar cellular issues.
Takeaways
- 💓 **Cardiovascular System Function**: The heart and blood vessels work together to deliver glucose and oxygen to cells and remove carbon dioxide and waste efficiently.
- 🚫 **Cardiovascular Disease Types**: There are two main types of cardiovascular diseases: atherosclerosis and blood clotting.
- 🛑 **Atherosclerosis Process**: Begins with risk factors causing damage to the artery's endothelium, leading to an inflammatory response and the recruitment of white blood cells.
- 🔍 **White Blood Cell Role**: White blood cells absorb saturated fats and cholesterol from LDLs, leading to the development of an atheroma behind the endothelium.
- 📈 **Atheroma Development**: Over time, the atheroma can calcify, lose elasticity, and form a plaque, which is a key indicator of atherosclerosis.
- 🌐 **Lumen Narrowing**: The atheroma bulges into the lumen of the artery, narrowing it and reducing blood flow.
- 🚫 **Consequences of Narrowed Lumen**: Reduced blood flow leads to decreased oxygen and CO2 exchange, affecting the rate of diffusion and cellular respiration, potentially leading to cell death.
- 🩸 **Blood Clotting Process**: Damaged endothelium exposes collagen fibers, activating platelets and initiating the clotting cascade.
- 🔄 **Clotting Cascade**: The activation of prothrombin to thrombin converts fibrinogen into insoluble fibrin, forming a mesh that traps more blood cells and platelets, creating a clot.
- ⚠️ **Risk Factors**: High blood pressure and high levels of LDL in the blood are risk factors that can lead to cardiovascular disease.
- 🚑 **Disease Impact**: In cardiovascular disease, the processes of inflammation and clotting occur too often, leading to obstructions that reduce blood flow and cellular function.
Q & A
What is the primary function of the cardiovascular system?
-The primary function of the cardiovascular system is to ensure that glucose, oxygen is delivered to cells efficiently, and that carbon dioxide and waste are effectively removed from cells.
What are the two types of cardiovascular diseases mentioned in the script?
-The two types of cardiovascular diseases mentioned are atherosclerosis and blood clotting.
What causes atherosclerosis to begin?
-Atherosclerosis begins with various risk factors causing damage to the endothelium of the arteries, which are under high pressure.
What is the role of white blood cells in the development of atherosclerosis?
-White blood cells are recruited to the site of endothelial damage, absorb saturated fats and cholesterol from circulating LDLs, and form foam cells behind the endothelium, leading to the development of an atheroma.
What is an atheroma and how does it affect blood flow?
-An atheroma is a collection of white blood cells that have absorbed LDLs, forming a bulge into the arterial lumen, which narrows the lumen and reduces blood flow.
How does the narrowing of the arterial lumen due to atheroma impact cells?
-Narrowing of the lumen reduces blood flow, which in turn reduces oxygen supply and CO2 removal. This reduces the concentration gradient around tissue cells, slowing down the rate of diffusion, and ultimately reducing cellular respiration and ATP production, which can lead to cell death if cells cannot function.
What initiates the blood clotting process?
-Blood clotting is initiated when the endothelium is damaged, exposing collagen fibers that activate platelets in the blood.
What is the role of platelets in blood clotting?
-Activated platelets form a temporary platelet plug and trigger the conversion of prothrombin to thrombin, which converts fibrinogen into insoluble fibrin, forming a mesh that traps more red blood cells and platelets to form a blood clot.
How can blood clots formed due to cardiovascular disease affect the body?
-Blood clots can become free from the blood vessel and obstruct arteries, reducing blood flow, oxygen supply, and CO2 removal from cells, which can lead to insufficient respiration, reduced ATP production, and cell dysfunction or death.
What are the risk factors that predispose individuals to developing cardiovascular diseases as described in the script?
-The risk factors include high blood pressure that causes damage to the endothelium and high levels of LDL cholesterol in the blood.
How do the processes of inflammation and blood clotting normally function in the body?
-Inflammation and blood clotting are part of the body's natural healing and repair mechanisms. Inflammation helps to heal or repair damaged tissues, while blood clotting seals up blood vessels to prevent leakage of the transport medium.
Outlines
💓 Understanding Cardiovascular Disease
The paragraph delves into the functioning of the cardiovascular system and how it delivers glucose and oxygen to cells while removing waste. It introduces two types of cardiovascular diseases: atherosclerosis and blood clotting. The focus is on atherosclerosis, which begins with damage to the endothelium due to risk factors like high blood pressure and high LDL levels. This damage triggers an inflammatory response, leading to the recruitment of white blood cells. These cells absorb LDL cholesterol, leading to the formation of an atheroma behind the endothelium. Over time, the atheroma can calcify and lose elasticity, forming a plaque that narrows the artery lumen.
🚫 Consequences of Narrowed Artery Lumen
This section discusses the consequences of atherosclerosis, specifically how the narrowing of the artery lumen due to plaque formation reduces blood flow. This reduction in blood flow leads to decreased oxygen and nutrient supply to cells, as well as impaired waste removal. The decreased concentration gradients around tissue cells slow down the rate of diffusion. This can reduce cellular respiration, leading to a decrease in ATP production, which is essential for cell function. If cells cannot function properly due to lack of ATP, the tissue they are part of can die.
🩸 Blood Clotting and Its Impact
The final paragraph addresses blood clotting, another cardiovascular disease process. It explains how damage to the endothelium exposes collagen fibers, which activates platelets and initiates the clotting process. Platelets form a temporary plug and activate enzymes that convert fibrinogen into insoluble fibrin, creating a mesh that traps more blood cells and platelets, forming a clot. While clotting is a normal response to repair damage, in individuals with cardiovascular disease, this process can occur too frequently. Blood clots can break free and obstruct arteries, further reducing blood flow, oxygen supply, and CO2 removal. This can lead to a decrease in the concentration gradient for diffusion, insufficient cellular respiration, and inadequate ATP production, ultimately impairing cell function.
Mindmap
Keywords
💡Cardiovascular System
💡Atherosclerosis
💡Endothelium
💡Inflammatory Response
💡White Blood Cells
💡LDL Cholesterol
💡Plaque
💡Blood Clotting
💡Thrombin
💡ATP
Highlights
The cardiovascular system's role in delivering glucose and oxygen to cells and removing carbon dioxide and waste.
Cardiovascular diseases primarily affect the heart and blood vessels.
Two main types of cardiovascular diseases: atherosclerosis and blood clotting.
Atherosclerosis begins with risk factors damaging the artery's endothelium.
Damage to the endothelium triggers an inflammatory response and recruitment of white blood cells.
White blood cells absorb saturated fats and cholesterol from LDLs, leading to atheroma formation.
Atherosclerosis involves the development of plaques that can calcify and lose elasticity.
Atheroma formation narrows the blood vessel lumen, reducing blood flow.
Reduced blood flow affects oxygen and carbon dioxide exchange, impacting cellular respiration.
Decreased cellular respiration leads to reduced ATP production and potential cell death.
Blood clotting involves damaged endothelium exposing collagen fibers, activating platelets.
Platelet activation leads to the formation of a temporary platelet plug and the clotting cascade.
Thrombin converts fibrinogen into fibrin, forming a mesh that traps more blood cells and platelets.
Blood clots can obstruct arteries, reducing oxygen supply and CO2 removal from cells.
In cardiovascular disease, clotting processes occur too frequently, leading to health complications.
Blood clots can break free and travel, potentially causing further obstructions in the circulatory system.
The consequences of blood clots include reduced blood flow, oxygen supply, and cellular respiration.
Without sufficient ATP, cells dependent on the affected artery cannot function properly.
Transcripts
you know once we looked at the
functioning of the cardiovascular system
we then have to look at cardiovascular
disease okay so you look at the heart
the blood vessels and we know how they
work together to ensure that glucose
oxygen is delivered to cells efficiently
and that carbon dioxide and waste are
effectively removed from cells okay now
let's look at how cardiovascular disease
affects that so there's two cardio
vascular disease types that you need to
know about the first is atherosclerosis
and the next one is blood clotting okay
so know these events basically and be
able to explain their consequences so
let's go now atherosclerosis
one begins with various kind of risk
factors causing damage to the
endothelium usually of the artery okay
because those are the ones that have the
high pressure in them
okay so damage to the endothelium the
damage to the endothelium causes an
inflammatory response again I'm going
over the mark scheme points here so it's
gonna be very succinctly but you need to
explain this as a story so damage to the
endothelium causes an inflammatory
response that causes the recruiting the
recruiting of white blood cells very
important okay so the white blood cells
so you got damage to the endothelium
here and the white blood cells come
along and in they go okay behind the
endothelium the white blood cells end up
here okay now once they're there the
white blood cells white blood cells
absorb
now remember this these people the
people that are most likely to have
these events occurring are gonna have a
they're gonna have high blood pressure
causing damage to the endothelium and B
they are going to have a diet on diet
but they're gonna have high levels of
LDL in their blood so white blood cells
absorb saturated fats and cholesterol
saturated fats and cholesterol from
circulating LDLs and we'll come back to
this we'll review this as well but
individuals with a high risk or a high
risk of developing cardiovascular these
disease are gonna have high blood
pressure that causes damage to the
endothelium and they're gonna have high
circulating LDLs in their blood so the
white blood cells absorb saturated fats
and cholesterol from LDLs and this
causes the development of the atheroma
okay behind behind the endo behind the
endothelium okay and the last point
would be remember we're summarizing here
not too much information that as as this
develops so so the atheroma can become
can become calcified
okay calcified and loses elasticity
loses elasticity to form a plaque and
atherosclerosis
plaque these are the key points right
here okay now I will stop there so
basically what's happening is damage to
the endothelium happens the white blood
cells arrive and as the white blood
cells arrive as they absorb more and
more LDLs
from the circulation okay there they're
forming foam cells behind the
endothelium the endothelium is still
covering them endothelium is still
covering them but as as they're
absorbing more and more LPL's this
atheroma is causing a bulge in to be
into the lumen oh that's a key point
that I forgot atheroma forms behind
endothelium narrows lumen how could I
forget that narrows lumen okay and we're
going to come back to this as to what
consequence is going to have okay this
is a key point
actually let's just follow through
immediately okay so we've got narrows
lumen and let's look at the consequences
then of this if the lumen is narrowed it
reduces blood flow if it reduces blood
flow it will reduce co2 supply or bear
in mind co2 removal okay if the blood is
not flowing properly it's going to
reduce this and therefore it will reduce
the concentration gradients around the
tissue cells reduces the concentration
gradient and therefore this reduces the
rate of
diffusion and the key point is that if
you're not supplying oxygen and you're
not removing co2 this reduces
respiration this reduces the rate of
respiration in cells and therefore
reduces that ATP in the cells and
therefore cells cannot function cells
cannot function okay
and if the cells cannot function the
tissue will die right so that's that so
let's look at blood clotting then
remember everything blood clotting again
we're gonna look at how the different
risk factors can initiate these events
but the first event of blood flowing is
damaged damaged endothelium exposing
collagen exposed exposing collagen
fibers from behind the endothelium so
remember we said that the artery has
this thick elastic tissue elastic layer
will the reason the thing that makes it
elastic is collagen
okay collagen fibers but upon damage
those collagen fibers get exposed and to
these activates platelets in the blood
so the platelets in the blood are
activated okay and when they're
activated they form a platelet plug the
form a platelet plug which is temporary
okay but also they this causes the
activation activation of another kind of
enzyme as in the blood activation of the
enzyme from prothrombin to thrombin
okay activation of pro programming into
the active enzyme thrombin and what from
Bandhan does is it converts soluble
soluble protein fived reno gen soluble
protein fibrinogen into insoluble fiber
in okay and this forms these traps so
fibrin the fibrin mesh traps more red
blood cells red blood cells and more
platelets ie the positive feedback more
more red blood cells and more platelets
to form a blood clot okay now under
normal situation just like with
atherosclerosis under normal system
situation the inflammatory response is
just there to kind of heal or repair the
damage same with blood crying it's there
to seal up the blood vessel so that the
blood vessel doesn't leak the transport
medium however in people with
cardiovascular disease these processes
are happening too often and too much
okay so what happens as a result of the
formation of blood clots in blood
vessels so blood clots blood clots can
kind of become free from the blood
vessel so blood clots can obstruct can
obstruct arteries and when they obstruct
an artery again they is the same thing
they reduce blood flow therefore they
reduce
the oxygen supply and the removal of co2
from cells and this reduces the
concentration gradient which reduces the
rate of diffusion which means that
there's not enough respiration happening
in cells and therefore they don't create
enough ATP and without ATP the cells
that were dependent upon this artery for
their supply and removal cannot function
okay so this is cardiovascular disease
let's move on
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