Y1 - The Cardiovascular System Flashcards
What are the main components of the cardiovascular system?
The heart, blood vessels (arteries, veins, capillaries), and blood.
What is the primary function of the cardiovascular system?
To transport oxygen, nutrients, hormones, and waste products throughout the body.
What is the role of the heart in the cardiovascular system?
The heart pumps blood through the blood vessels, supplying oxygen and nutrients to tissues and removing waste.
What is the structure of the heart?
The heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers).
What is the function of the right atrium?
The right atrium receives deoxygenated blood from the body through the superior and inferior vena cava and pumps it into the right ventricle.
What is the function of the right ventricle?
The right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery for oxygenation.
What is the function of the left atrium?
The left atrium receives oxygenated blood from the lungs via the pulmonary veins and pumps it into the left ventricle.
What is the function of the left ventricle?
The left ventricle pumps oxygenated blood to the rest of the body through the aorta.
What are valves in the heart, and what is their role?
Valves (e.g., tricuspid, bicuspid, pulmonary, and aortic valves) ensure one-way blood flow through the heart and prevent backflow.
What is the role of the coronary arteries?
The coronary arteries supply the HEART muscle with oxygenated blood to support its function.
How are the blood vessels classified? (there are five)
Blood vessels are classified into arteries, arterioles, venules, veins, and capillaries.
Which vessel surrounds bodily tissue / organs that helps deliver oxygen and nutrients to cells and remove waste products
Capillaries.
What is the structure and function of arteries?
Arteries have thick, muscular walls to carry oxygenated blood away from the heart under high pressure. The largest artery is the aorta.
What is the structure and function of veins?
Veins have thinner walls than arteries and carry deoxygenated blood towards the heart. They contain valves to prevent backflow.
What are capillaries, and what is their role?
Capillaries are tiny blood vessels where the exchange of oxygen, nutrients, and waste products occurs between the blood and tissues.
What is the function of the superior vena cava?
The superior vena cava carries deoxygenated blood from the upper body to the right atrium of the heart.
What is the function of the inferior vena cava?
The inferior vena cava carries deoxygenated blood from the lower body to the right atrium of the heart.
What is the role of the pulmonary arteries?
The pulmonary arteries carry deoxygenated blood AWAY from the right ventricle to the lungs for oxygenation.
What is the role of the pulmonary veins?
The pulmonary veins carry oxygenated blood from the lungs to BACK to the left atrium.
What is the aorta, and what is its function?
The aorta is the largest artery in the body, carrying oxygenated blood from the left ventricle to the rest of the body.
What is the function of the septum in the heart?
The septum is a thick wall that divides the heart into left and right sides, preventing the mixing of oxygenated and deoxygenated blood.
How many layers are there in the heart?
Three (epicardium, myocardium and endocardium)
Which layer of the heart is known as muscular, middle layer?
myocardium
Muscles can be placed in three main
types. What are they?
- Skeletal Muscle
- Smooth Muscle
- Cardiac Muscle
What is the role of the Pulmonary Circuit?
carries deoxygenated blood to the lungs from RA (via pulmonary artery) and oxygenated blood back to the heart/LA (via pulmonary vein)
What is the role of the Systemic Circuit?
carries oxygenated blood to the body tissues from LV (via AORTA) and deoxygenated blood back to the heart/RA (via VEINS/VENA CAVA)
What does SA node stand for, and describe its role
Sino Atrial Node. Acts as the heart’s natural pacemaker, by generating its
own electrical signals automatically. It can receive messages from the nervous system to adjust the heart rate.
Define MYOGENIC
the capacity of the heart to generate its own electrical impulse, which causes the cardiac muscle to contract
What is the conduction system?
Heart is a specialised network of cells that controls the heart’s rhythm by generating and conducting electrical impulses throughout the heart
What stages does the electrical impulse pass through in the conduction system consist of?
- SA Node (Sinoatrial Node)
- AV Node (Atrioventricular Node)
- Bundle of His
- Purkinje Fibers
Outline the first process in the conduction of the heart and explain what it causes.
The SAN sends out an electrical impulse - causing the atria to contract and forcing blood into the ventricles
What role does the AV node play during the conduction of the heart?
Slows the electrical impulse down slightly before sending it to the ventricles. This delay allows the atria to empty fully before the ventricles contract.
What does the Cardiac Cycle refer to?
Refers to the sequence of events that occur during one heartbeat, when emptying and filling the heart - including contraction (systole) and relaxation (diastole) of heart chambers.
What happens to the atria during the diastolic phase?
The atria relax and fill with deoxygenated blood from the body (right atrium) and oxygenated blood from the lungs (left atrium).
What happens to the ventricle during the diastolic phase?
The ventricles relax and fill with blood from the atria.
What happens to the atria in the systolic phase?
It squeezes (contracts), forcing blood into the ventricles
What happens the ventricles in the systolic phase?
They contract, forcing blood out of the heart
Does the heart relax or contract in the diastolic phase?
Relax
Does the heart relax or contract in the systolic phase?
Contract
Define heart rate and provide its unit of measurement
The number of times the heart beats per minute
Beats per minute (BPM)
Define stroke volume and provide its unit of measurement
The amount of blood pumped out of the left ventricle PER BEAT
mL or litres (per beat)
Define cardiac output and provide its unit of measurement
The amount of blood pumped out of the left ventricle PER MINUTE
mL or litres/per min
Outline the relationship between heart rate, stroke volume and cardiac output
Cardiac output (Q) = stroke volume x heart rate.
Therefore, if either SV or HR increase, Q will increase
What is the cardiac output of a performer with a heart rate of 63bpm and a stroke volume of 80ml
5040 ml/min or 5.04 L/min
Describe Maximal exercise
This is physical activity performed at
the highest intensity level an individual can achieve. It pushes the body to its absolute limit.
Describe sub-maximal exercise
This is physical activity performed at an intensity level that is below the maximum capacity of an individual. It doesn’t push the body to its utmost limit
What happens to HR rate during SUB-MAXIMAL exercise & why?
It will rapidly increase initially, but then plateau as O2 intake meets the exercise demands
What happens to HR rate during MAXIMAL exercise & why?
It will rapidly increase initially, but continue to increase due to greater demand for O2 during incremental workloads.
What happens ot SV during exercise?
SV increases as exercise increases, but only increases up to 40-60% of
maximum effort/intensity.
What is cardiac hypertrophy?
Refers to the thickening of the heart muscle walls (myocardium layer), particularly in the ventricles, resulting in an increase in the size & strength of the heart.
Define the term venous return
It is the volume of blood flowing back to the heart via the veins, specifically returning to the right atrium.
Describe the 6 steps of Starling’s Law
- During exercise, there is a greater venous return
- Therefore, a greater amount of blood fills the atria, before entering the ventricles
- Therefore, there is a greater stretch of the ventricular walls of the heart
- Therefore, there is a greater force of contraction
- Therefore, there is a greater stroke volume
- Therefore, there is greater amount of oxygenated blood to the working muscles
Identify the 5 mechanisms that assist in venous return during exercise
1) Pocket Valves
2) Skeletal Muscle Pump
3) Respiratory Pump
4) Smooth Muscle
5) Gravity
Describe the role of the Skeletal Muscle Pump
Veins situated between skeletal muscles which help squeeze blood back to the heart when they contract and relax
Describe the role of Respiratory Pump
Pressure changes occur in the thoracic and abdominal cavities as the respiratory muscles contract. These pressure changes compress the nearby veins and assist the flow of blood back to the heart.
Describe the role of Pocket Valves
One-way valves prevent back flow of blood & allow one-direction flow towards the heart
Describe the role of Smooth Muscle
thin layer of smooth muscle helps
squeeze blood back towards the heart via vasodilation &
constriction
Describe the role of gravity
blood from upper body is aided in its return by
gravity
How can a cool down aid towards venous return?
Performing an active cool-down
keeps the skeletal muscle pump and
respiratory pump working, thus
preventing the blood from pooling.
What does CCC stand for?
Cardiac Control Centre
Where is the Cardiac Control Centre found and what nervous system is it art of?
Found in the Medulla Oblongata of
the brain; this is part of the
Autonomic Nervous System (ANS).
How many sub-divisions does the ANS have? What are they called?
Two. Sympathetic & para-sympathetic
Outline the role of the Sympathetic Nervous System (SNS)
Speeds up heart rate via the cardiac accelerator nerve
Outline the role of the Parasympathetic Nervous
System (PNS)
Slows heart rate through the vagus nerve.
What is the role of the Cardiac Control Centre?
Regulates heart rate by controlling the activity of the autonomic nervous system (ANS). Its role is to ensure the heart rate meets the body’s demands during rest and exercise
State the three control mechanisms of heart rate (HR)
- Neural
- Hormonal
- Intrinsic
Which control mechanisms are considered external control mechanisms of the heart?
Neural & Hormonal
Which control mechanism is considered an internal control mechanism of the heart??
Intrinsic
Neural Control = ?
RECEPTORS
Identify and outline the role of each receptor involved in NEURAL control (as part of the CCC)
- Chemoreceptor - detects chemical changes in the body e.g., high levels of CO2/decrease in pH/hypoxia
- Baroreceptor - detects changes in blood pressure
- Proprioceptors - detects changes in muscle length (muscle spindle) and tension (golgi-tendon organ)
Hormonal Control = ?
ADRENALINE - secreted by the adrenal gland
Describe how the HORMONAL control mechanism helps regulate HR
SNS activation → stimulates the adrenal medulla → adrenaline is released into the bloodstream → stimulating the SA node to increase HR
Intrinsic control =
Temperature & Venous Return
Explain how venous return & temperature (INTRINSIC CONTROL) help regulate HR during exercise?
Venous Return = more blood returns to the heart → causes walls of atria/ventricles to stretch → triggers stretch receptors, leading to increased SA node activity and a faster heart rate & SV
Temperature = an increase in body/muscle/heart temperature → stimulates the SA node to fire more frequently → increasing HR.
What are are the 4 components of blood?
Plasma = ~55%
Red Blood Cells = ~45%
White Blood Cells = <1%
Platelets = <1%
What are the functions of blood?
- Transport key nutrients (glucose, amino acids & fatty acids)
- Transport system for O2 (in) and CO2 (out) & hormones
- Maintain homeostasis - Temperature Regulation & fluid balance
- Protect & fight diseases
Summarise how blood flows through the vascular system
heart (LV) → arteries → arterioles → capillaries → venules → veins → heart (RA)
Which blood vessel exerts the highest pressure & why? Make reference to their characteristics.
The arteries (specifically the aorta) exert the highest pressure because they carry oxygenated blood away from the heart, propelled by the forceful contraction of the left ventricle during systole.
Their thick, elastic walls allow them to withstand and maintain this high pressure.
What does Vascular Shunting refer to?
The redistribution of blood during exercise.
What % of blood flow takes place towards the SKELETAL MUSCLES during REST?
~20%
What % of blood flow takes place towards the SKELETAL (working) MUSCLES during exercise?
~80%
What happens blood flow during REST & why?
During REST, blood flow (80%) primarily goes to the brain, kidneys,
liver, skin (even intestines) to carry out normal body functions such
as digestion and removal of waste products
What happens blood flow during EXERCISE & why?
Exercise causes an increased demand for oxygen from the muscles, where
80% of blood flow is now redirected to the working muscles
Blood is diverted TO the working muscles and AWAY (20%) from the non-essential organs (e.g., kidneys) to maximise blood flow to
What is VASOCONSTRICTION ?
when the lumen gets narrower/smaller - limiting blood flow
What is VASODILATION?
when the lumen gets wider/bigger - increasing blood flow
What are pre-capillary sphincters?
Rings of muscle at the junction between the arterioles & capillaries.
They can effectively “open” or “close” the capillaries leading to the muscles or the organs
Explain the action of smooth muscle to help with re-distribution of blood towards the working muscle
The action of the smooth muscle around the arterioles includes vasodilation & vasoconstriction.
The action of pre-capillary sphincters will further assist in the direction blood to where it is needed and restrict it where it is not needed
What are the key components in the VASCULAR SHUNT ?
VCC
vasoconstriction
vasodilation
pre-capillary sphincter
What does VCC stand for?
Vasomotor Control Centre
What is the main role of neural control within the VCC?
Neural control in the VCC dictates whether the pre-capillary sphincter opens or closes - helping redistribute blood appropriately.
