LO3: Cardiovascular System Flashcards
Parts of the cardiovascular system
Cardio (heart)
Vascular (Vessels)
Blood
Aorta
Main artery.
Originates in the left ventricle and carries oxygenated blood to all parts of the body except the lungs
Superior Vena Cava
Vein that receives deoxgygenated blood from the upper body to empty into the right atrium of the heart
Inferior Vena Cava
Vein that receives deoxygenated blood from the lower body to empty into the right atrium of the heart.
Pulmonary vein
Carries oxygenated blood from the lungs to the left atrium of the heart.
Pulmonary artery
Carries deoxygenaged blood from the heart and back to the lungs.
It’s the only artery that carries deoxygenated blood
The pathway of blood
Vena cava
Right atrium
Tricuspid valve
Right ventricle
Semi-lunar pulmonary valve
Pulmonary artery
Lungs
Pulmonary vein
Left atrium
Bicuspid valve
Left ventricle
Semi-lunar aortic valve
Aorta
Body
Vena cava
Cardiac output (CO or Q)
The amount of blood ejected from the heart in one minute.
Usually around 5000mls/min (5l/min) at rest. This is because even at rest the same amount of blood needs to be circulating our body.
When exercising your body needs more oxygen.
At that time, your body can change its cardiac output by adjusting your heart rate and stroke volume.
Stroke volume (SV)
The volume of blood pumped out of the left ventricle of the heart during each systolic cardiac contraction.
A typical stroke volume for an adult is between 50ml and 100ml, the average is approx.
70ml for a 70kg male.
It can vary due to the size of a person and the amount of exercise the person does.
Heart Rate (HR)
The number of times your heart beats per minute (BPM). The average heart rate of an average afult is between 60 and 80 bpm
What happens to the heart when it stretches and recoils?
the further it’s stretched, the qucker and more powerful the heart can recoil and increase in size.
The greater the VR, the greater the SV
Types of blood vessels - arteries
Have a thicker tunica media than veins, containing smooth muscle.
The smooth muscle allows the lumen to change size, adjusting blood pressure as needed.
They have more elastin, which allows them to stretch and recoil, unlike veins.
This helps with keeping blood flowing in one direction and stops backflow.
Types of blood vessels - arterioles
These linked arteries and capillaries. Smaller in diameter (compared to arteries).
They can change their lumen size and changes the flow of blood.
At the end of the arteriole = ring of muscle called the pre-capillary sphincter.
Types of blood vessels- capillaries
Thinnest of the vessels at just one cell thick. O2, CO2 and other nutrients can pass through them into the muscles and cells because they are only one cell thick.
Types of blood vessels- venules
Link the capillary with the veins. They collect blood from the capillaries and funnel it into the vein.
Pressure in the venules and veins is much lower than arteries, rely on blood flow to keep moving.
Types of blood vessels- Veins
These return blood to the heart. They have little smooth muscle, due to having a smaller tuncia media (middle layer).
They have the largest lumen to allow increased blood volume.
The tunica intima (inside layer) has valves unlike other vessels.
Veins cannot produce their own pressure to push blood through, how does the blood return?
Veins are located in muscles, as it contracts it squeezes the vein and pushes the blood through.
Red blood cells: Erythrocytes
Carry oxygen to all living tissue. They contain a protein called haemoglobin which gives the red colour.
When combined with oxygen (02) it becomes oxyhaemoglobin.
They are round, flattened discs with an indented shape which gives a large surface area and allows them to flow easily within plasma.
One drop of blood contains millions of red blood cells.
Plasma
Straw-coloured fluid which contains all blood cells.
Made up of approx. 90% water as well as electrolytes such as sodium, potassium and proteins.
It carries carbon dioxide, dissolved as carbonic acid, glycogen and triglycerides.
White blood cells: leucocytes
These protect the body from infection.
They identify, destroy and remove pathogens such as bacteria or viruses.
White cells originate in the bone marrow and are stored in your blood.
Platelets: Thrombocytes
Disc-shaped cell fragments produced in the bone marrow.
The primary function of platelet is clotting to prevent blood loss.
Vasodilation
dilation (widening) of a blood vessel reducing blood pressure, increasing blood flow.
Vasoconstriction
constriction (narrowing) of a blood vessel increasing blood pressure, reducing blood flow.
Vascular Shunt
2 mechanisms are involved.
1. Vasodilation and Vasoconstriction of arterioles: Vasodilation of arterioles that supply the skeletal muscles increases blood flow to the muscles whilst vasoconstriction of arterioles that supply the organs (eg; liver) reduces blood flow to the organ.
2. Precapillary Sphincters open in the skeletal muscle and close in the organs, altering blood flow.
This means a large increase of blood to the working muscles and to the skin if exercise continues, helping us to cool down.
Function of the cardiovascular system- delivering oxygen and nutrients
When exercising the CV system responds to ensure supply meets demand.
When the CV system can no longer meet the demands, fatigue will occur in the muscles and performance will deteriorate.
Functions of the cardiovascular system- removing waste products: carbon dioxide and lactate
Waste products are carried to the kidneys and liver, whilst carbon dioxide is returned to the lungs.
During exercise, your body produces more CO2 and lactate.
It is essential these are removed otherwise muscle fatigue will occur.
Functions of the cardiovascular system- fighting infection
Leuco\c|ytes (white blood cells) are constantly produced inside the bone marrow. They can consume and ingest pathogens (substance that cause illness) and destroy them, produce antibodies that will destroy pathogens, and produce antitoxins which neutralise the toxins that may be released by pathogens
