The Heart Flashcards
Learn about the heart and the processes involved
Draw the heart
see diagram
why do we need a circulatory system
to transport materials around the body.
what is transported
oxygen, waste products (Co2, urea), food (glucose,vitamins,minerals,amino acids)
what does circulatory system consist of?
blood, blood vessels, heart
label diagram of heart
see notes
describe pathway of blood through heart
vena cava, right atrium, tri cuspid valves, right ventricle, pulmonary artery, pulmonary vein, left atrium, bicuspid valve, left ventricle, aorta.
Difference between right and left side
Right side is thinner, has to contract and pump blood to only one place that is close (lungs). Left is thicker, has to contract and pump blood all over body. Right has deoxygenated blood, left has oxygenated blood.
what is the function of the septum?
it separates the right side from the left.
function of the heart
It is a pump which pushes the blood all over the body.
location of the heart
between lungs and chest. in the thorax cavity
what is the heart made up of?
cardiac muscle. Never tires but can’t regenerate itself after dying. Only regenerates with CPR
which vessel supplies the heart with blood?
the coronary artery. these branch from the aorta just above the semi lunar valves
Describe the two types of circulatory systems
Open circulatory system: heart pumps blood into vessels that are open ended. Eg. Insects
Closed circulatory system:heart pumps blood in a continuous system of blood vessels. Eg. Humans
Describe the process in an open circulatory system
Blood arrives at cell through artery from heart.
Leaves the blood vessel and enters cell. The blood and cell exchange materials. (O2 and CO2)
Blood leaves cell back up vein to heart.
Describe closed circulatory system.
Blood arrives to cell from heart via artery.
Remains in blood vessel.
Materials diffuse from blood into cells via capillaries and vice versa.
Blood returns to heart via a vein.
Advantages of a closed circulatory system
Blood can be pumped faster so nutrients delivered faster.
Blood flow rate to different organs can be changed if needed. Eg. Blood flow increased to legs during exercise.
Name the two types of circuits in a human.
Systematic circuit: blood exchanged between heart and body cells
Pulmonary circuit: blood exchanged between heart and lungs
Advantages of having a double circulation system
Separates oxygen rich and oxygen poor blood.
Blood pressure can be kept high enough to reach all parts of the body.
Name the types of organisms that don’t have a circulatory system
how they transport materials
Why circulation system not needed
Small organisms
Eg. Amoeba
Transport materials in and out of cells by diffusion.
Cells are only a few cells thick therefore diffusion is effective.
What is blood pressure
The force of blood pushing against the walls of the arteries as it pumps blood.
Importance of blood pressure
If stays high over time it can damage the body.
Greater force on arteries so heart is under more pressure.
Diseases caused by high blood pressure
Coronary heart disease,
Heart failure,
Stroke,
Kidney failure
How blood pressure measured and the average
Blood pressure monitor. 2 readings Average: 120/80 Top- when ventricles are contracting Bottom- when ventricles are relaxed
If over 95- high BP- hypertension
Lifestyle habits that effect circulatory system
1. Smoking
- Nicotine increases the heart rate and blood pressure. Bigger workload on heart, so muscle strained.
- CO2 reduces the amount of O2 carried by the blood. So blood has to be pumped harder as less O2 in it.
- Other chemicals in tobacco increase the chance of clots, so less circulation.
Lifestyle habits that effect circulatory system
2. Diet
- High intake of fat, builds up cholesterol. May block up artery and cause stroke as heart under more pressure to pump blood through narrow vessel.
- High salt intake, raises BP which can cause heart attack as heart under pressure
Lifestyle habits that effect circulatory system
3. Exercise
- Exercise strengthens the heart, improving circulation and means heart doesn’t have to pump as hard, so under less pressure.
- Exercise increases our ability to transport oxygen. Increased energy levels and puts less pressure on heart to pump.
Name the different blood groups
A, B, AB, O
What are blood groups determined by?
The presence of the chemical Antigen on a persons red blood cell.
Why is it important to know a persons blood group?
For safe blood transfusion.
It is important to match blood of receiver with blood of donor.
If not can cause blood clumping in receiver.
Blood group O
No antigens present in RBC
Universal donor as doesn’t contain chemical so not recognised as foreign.
Can only receive blood from O as A and B would be recognised as foreign.
Blood group A
Can give to AB and A
Can receive blood from A and O
Blood group B
Can give to AB and B
Can receive from O and B
Blood group AB
Universal receiver as can receive from all types.
Can only give to AB. Has antigens that will be recognised as foreign and be rejected except for AB
Explain Rhesus Factor
Another blood grouping system.
Antigen called factor D
If you have factor D- Rhesus positive/Rh+
If you don’t have factor D- Rhesus negative/Rh-
Rhesus factor in blood transfusions
Rh- can be given to Rh+ as no factor D present that can be rejected
Rh+ can’t be given to Rh- as factor D present and seen as foreign
Importance of Rhesus factor in pregnancy
Problems may arise in 2nd or further pregnancies.
If mother Rh- and the first baby is Rh+, mothers blood can’t match Rh+ so makes antibodies against Rh+ blood.
So if 2nd baby Rh+ the mother will recognise it as foreign and problems arise as mothers blood can then damage the RBC in the baby.
How is heartbeat controlled
By SA node (sinoatrial node) also called pacemaker.
Brain and nerve cells can also effect the rate.
Name location of SA node
Full name of AV node
Top of right atrium.
AV- Atrioventricular node
What is contraction and relaxation of heart muscle called
Contraction- Systole
Relaxation- Diastole
Sequence of events in cardiac muscle
- Blood enters atria, all valves closed, chambers relaxed.
- Atria contract (systole), tri and bicuspid valves open, blood forced into ventricles.
- Atria relax (diastole), ventricles contract(systole), bi and tri close, semi lunar valves open, blood forced into pulmonary artery and aorta.
- Ventricles relax (diastole), semi lunar close, cycle starts again
The role of SA and AV in systole and diastole.
- SA emits electrical system
- Causes atria to contract
- Signal picked up by AV
- AV sends signal to ventricles down specialised muscle fibres in septum (bundle of HIS)
- Fibres pick up signal causing ventricles to contract.
Factors that affect heart rate
Increase: exercise, stress, excitement, caffeine, anxiety.
Ðecrease: sleep, alcohol
Pulse definition
A pulse is the alternate expansion and contraction of the arteries.
What is the pulse
How is it measured
Average
What is sound of heartbeat caused by
Ventricles push blood up the aorta causing it to expand, resulting in all the arteries expanding.
Measured at wrist, neck and temple
Average: 72 bpm
Sound caused by closing of valves in the heart
What is a portal system
A system which begins and ends in capillaries. Does not connect directly to heart.
Example of portal system
Hepatic portal system.
Consists of hepatic vein, liver and small intestine.
Function: transport digested materials (eg. Glucose) to the liver to be stored as glycogen.
Main gas in right side of heart and how transported
CO2
Transported dissolved in plasma
