Organisation of the CVS - L1 Flashcards
Test book human - gender/weight/HR/BP?
70Kg Male
Resting pulse HR - 70bpm
BP - 120/80mmHg
What is the change of HR that it can be for example with exercise and training?
Magnitude of change e.g. from rest to strenuous exercise – HR can increase from 70bpm to 200bpm (3 fold)
Range: Rarely do we encounter a textbook person e.g. resting HR ranges from 60- 85bpm; potentially <30bpm with training
Risk factors for Cardiovascular disease? HINT 10
- High blood pressure
- Unhealthy diet
- High cholesterol
- Diabetes
- Tobacco
- Overweight and obesity
- Air pollution
- Kidney disease
- Physical inactivity
- Harmful use of alcohol
What are the 3 fundamental components of the CVS?
Heart, blood and blood vessels
How does the body ensure that the metabolic needs of all cells are met? Homeostasis wise
The circulatory system contributes to homeostasis by transporting O2, CO2, wastes, electrolytes, and hormones from one part of the body to another.
Most basic and important function of CVS system:
To provide adequate blood flow to all body organs and tissues
Single-celled organism - Amoeba system?
Simple - Relies on diffusion between it and the environment
CVS system protective function?
Blood clotting - protects against haemorrhage
Pathogens - immune system
CVS system regulation function?
Hormones and thermoregulation - skin blood vessels
Transport of substances: Respiratory?
O2+CO2
Transport of substances: Nutritive?
Absorbed products of digestion
Transport of substances: Excretory?
Metabolic wastes delivered to liver and kidneys
Transport of substances: Regulation and protection?
Hormones, immune cells, clotting proteins to specific target cells
Basic function of the heart?
Pumps blood at high pressure
Basic function of the blood?
Transport medium in which materials to be transported are dissolved or suspended.
Basic function of the blood vessels - vasculature?
Passageways to distribute blood to all parts of the body and return it to the heart.
What are the blood vessels? 5
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
On average, how much blood?
5-5.5L about 8% of body weight
What does blood consist of and % wise?
Plasma - 55% of total blood volume
Specialised cellular elements - 45%:
-RBCs: Erythrocytes
-WBCs: Leukocytes
-Platelets
Function of platelets?
Blood coagulation - clotting
Function of WBCs?
Immunity/defence
RBC function?
Transport O2
What is plasma made up of?
Water, dissolved solutes e.g. ions, plasma proteins, other components e.g. metabolites, hormones, enzymes, antibodies
Is the pump on-off?
Pump is on-off
- Does pipe i.e. arteries and veins have a pressure gradient?
- Pipe in diameter?
- Do the walls of the pipe stretch?
- Is the pipe leaky?
- Pipe has a pressure gradient
- Pipe varies in diameter
- Walls of pipe can stretch in some places
- Some parts of pipe are leaky
CVS comprises multiple serial components?
Two circulations/loops (both originating and terminating at the heart):
Systemic circulation AND Pulmonary circulation
What is the systemic circulation?
Between the heart and all body systems. Supplies most organs and tissues
What is the pulmonary circulation?
Between the heart and lungs
Pump = heart, what is the systemic pump?
Left side - propels blood around the systemic circuit
Pump = heart, what is the pulmonary pump?
Right side - propels blood around the pulmonary circuit
Systemic circuit:
1. What kind of circuits?
2. Pressure in it?
3. Is the regulation independent?
- The Systemic circuit is comprised of many parallel circuits.
- It requires greater pressure for flow to many organs and is high pressure circuit, therefore,
left heart is a stronger pump. - This Parallel flow allows independent regulation of blood flow to organs
Pulmonary circuit - high/low pressure circuit?
Low pressure circuit, therefore right heart is a weaker pump
Which side of heart is stronger - left or right?
Left: systemic circuit is stronger to the right side: pulmonary circuit
VEIN DIAGRAM
What is the Cardiac Output (CO)? Formula?
It is the volume of blood ejected by each ventricle of the heart each minute.
CO = SV X HR
Factors in blood flow?
Pressure gradient and resistance
main component of blood?
Water
What is blood flow rate F?
The volume of blood passing through per unit time
Formula for F - flow rate?
F = Delta P/R
Where F = flow rate of blood through a vessel
Delta P = pressure gradient
R = resistance of blood vessels
Is Flow rate proportional to pressure gradient and vascular resistance?
Flow rate of blood is directly proportional to the pressure gradient (P) and is inversely proportional to vascular resistance (R)
What is the pressure gradient?
The DIFFERENCE (Delat) in pressure between the
beginning and the end of a blood vessel.
Where does circulation begin and end?
At the heart
Blood flows from an area of which pressures?
Blood flows from an area of high pressure to low pressure
What is resistance?
A measure of opposition/hindrance to blood flow
through the vessel
What happens to flow rate when resistance increases?
As resistance increases, flow rate decreases. Pressure gradient must therefore increase correspondingly to maintain flow rate
Number of prevalent cases of CVS disease in the world in 2015?
422.7 million
What is F driven by ?
Flow rate is driven by properties of the heart and blood vessels
What does the heart provide in terms of driving F?
Heart provides pulsatile driving force (contracts-relaxes) i.e. it is a pump (on – off – on –off)
- Heart input equals?
- Venous return equals?
- Heart input = Heart Output
- Venous return = Cardiac ouput
another way to describe Cardiac Output?
how much blood leaves ventricles of heart per minute i.e. per beat
It is both ventricles - but more focused on left side
What do blood vessels provide resistance to flow via?
Blood vessels provide resistance to flow via vessel radius
What is total peripheral resistance - TPR?
Total peripheral resistance (TPR) is the sum of the resistance of all peripheral vasculature (i.e. all organ circuits) in the systemic circulation.
Can the radius of arterioles be regulated? What is this important in controlling?
Yes the radius of arterioles can be regulated and is the key factor in controlling resistance to blood flow throughout the vascular circuit, and thus the distribution of CO.
CO proportional inversely/directly to MAP/TPR?
CO is proportional to MAP/TPR
MAP = mean arterial pressure
TPR = Total peripheral resistance
CO = cardiac ouput
Which has a higher pressure - arteries/capillaries?
arteries have a higher pressure than capillaries
What happens if there is sub-optimal functioning of the CVS?
Sub-optimal functioning: disease results
Diseases and disorders of heart and/or vasculature
compromise blood flow to organs
How does the body ensure that the metabolic needs of all cells are met?
Through optimal functioning of the CVS
Function integrated with that of other organ systems
can only eject what is being perceived
arterioles do all the hard work - actually do the offloading of O2 into capillary that gets into organ
vasodilation/constriction of arterioles can be regulated
resistance in all vessels - high sugar/high fats diet widespread in vasculature system - doesn’t just pick 1 vessel - affects the whole tree of the CVS all the way up to the heart. One may be more resistant than another but if 1 is diseased, all is diseased.
2022 figure of CVS disease in world and every year?
550 million living with it
16 million every year being diagnosed
