B1 Cardiovascular System

Question 1

Cardiovascular system consist of?

Answer 1

Heart, blood vessels and blood

Question 2

Function of the heart?

Answer 2

To pump blood around the body

Question 3

What’s the double circulatory?

Answer 3

Blood passes through the heart twice per cycle

Question 4

What’s myogenic?

Answer 4

When it beats/contacts without any nervous stimulation. Muscles cells are able to depolarize their own electrical impulses

Question 5

The heart structure is what?

Answer 5

Four chambers with a separated wall called septum. Upper chamber is the atrium and lower chamber is the ventricle

Question 6

Functions of Heart structure?

Answer 6

1) deoxygenated blood returns from the body in the vena cava and enters the right atrium.
2) blood is then passed into the atrio-ventricular valve (tricuspid valve) into the right ventricle and out the semi Lunar valves, into pulmonary artery.
3) blood is passed through the lungs and returns to the left atrium through the pulmonary vein.
4) blood passes a second atrio-ventricular valve (bicuspid valve) into left ventricle and through the semi Lunar valve into the aorta and then into the body tissue.

Question 7

Atrio-ventricular valves (heart valves) are?

Answer 7

Valves between atria and ventricles and prevents back flow of blood from ventricles to atria during ventricular systole

Open- greater pressure in the atria than ventricles
Closed- greater pressure in the ventricles than atria

Question 8

Semi Lunar (heart valves)

Answer 8

These valves are at the base of the arteries leaving the heart and prevent blood from returning to the ventricle during diastole (heart at rest)

Open- greater pressure in ventricles than atria
Closed- greater pressure in arteries than ventricles

Question 9

Structure of cardiac muscles

Answer 9

1) Cardiac muscle is only found in the heart and are striated (stripy) and is made up of repeating units.
2) cardiac muscle fibers are wider than skeletal muscles fibers
3) cardiac muscle are myogenic
4) cardiac muscles are branched which allows a faster signal propagation and contraction in three dimensions.
5) cardiac muscles consist of Y-shaped interconnected cells. Where one ends another begins this is a junctions called intercalated disc.
6) consist of double membranes with gaps of cytoplasm
7) have lots of mitochondria so more aerobic respirations

Question 10

Cardiac output

Answer 10

CO = SV x HR

SV = stroke volume (volume of blood expelled from left ventricles on one cardiac cycle)
HR = heart rate (number of cardiac cycle beats per mins)
Units = dm3 min-1

Question 11

Control of heart rate

Answer 11

1) internal pacemakers starts at the sinoatrial (SA) nodes which are located near the wall of right atrium.
2) electrical impulses from SA nodes causing two atrias to contract in unison. Called atrial systole.
3) pulses reaches a second node atrioventricular (AV) node between walls of ventricle, where it paused for 0.1 second before spreading walls of ventricle. This will allow the blood in atria to empty completely into ventricle before ventricle pump out the blood.
4) from AV node electrical impulses enters the bundle of his, then left and right bundle branches through the septum.
5) purkinje fibres conducts an impulse for apex of the heart up yhe ventricular myocardium causing ventricular contracts. Called ventricular systole

Question 12

Cardiac cycle?

Answer 12

Main purpose to pump blood around body.
1) atria contracts at the same time, forcing blood through the atrioventricular valves into ventricles. Closing of the atrioventricular valves produces a “lub” sound.
2) following a brief delay, the ventricle contract at the same time forcing blood through the semi lunar valves into aorta and the pulmonary artery. Closing if the semi lunar valves producing “dub” sound

Question 13

Features of arteries

Answer 13

Functions - transport blood fro heart to organ. Blood is under high pressure. Walls are thick to withstand the pressure

Structure :
Elastic tissue - withstands pressure
Smooth muscle tissue - strengthening
Endothelium - reduces friction and gives smooth flow
Narrow lumen - maintains pressure
Collagen - for protection

Question 14

Features of capillaries

Answer 14

Functions - walls only have endothelial layers that are one cell thick. This is involved in exchanges of materials between the blood and tissue cells which is the site of diffusion and the diameter is very small this would create greater frictions and high surface area reducing blood pressure and blood flow

Structure :
Very thin walls - increases rate of diffusion
Narrow diameter- ensures RBC is in contact with walls which increases RBC between capillaries walls
Walls spaces - gaps between cells and endothelial cells which allow rapid formation of tissue fluid and WBC to pass tissue spaces

Question 15

Features of veins

Answer 15

Functions - carry blood back to the heart from the tissue. Blood is under lower pressure therefore the vein wall does not need to be thick

Structure :
Large Lumen - to give low resistance
Thinner muscle layer - no need for vasco- constriction as all blood is going back into heart
Thinner elastic layer - as pressure is very low and walk doesn’t need to stretch and recoil
Semi-lunar valves - pressure is low. Stops back flow only allows blood to pass through in one direction to ensure blood goes back to the heart

Question 16

CVD genetics

Answer 16

If you have a family history of CVD this will increase your chance of suffering CVD. Example is familial hyper cholesterolaemia (FHC) where blood plasma cholesterol level is raised and can increase CVD

Question 17

CVD age

Answer 17

As you get older the risk of CVD increases

Question 18

CVD gender

Answer 18

Statically men are at a higher risk of dying CVD under the age of 50 then women. However, this changes women after menopause where the risk is then equal or slightly higher due to lack of oestrogen production

Question 19

CVD diet

Answer 19

Consuming high levels of saturated fats, high intake of salts , limited intake of healthy fats and vitamins. Increases risks of CVD

Question 20

CVD cholesterol levels

Answer 20

Blood cholesterol levels can increase due to high diet in saturated fats. However not all cholesterol are bad as it’s important for cell and nerve structure, brain development and for making steroid hormones

Question 21

CVD HDL:LDL

Answer 21

Cholesterol in blood can be part of both low density and high density lipoprotein (LDL is so called bad cholesterol and is associated with a risk of CVD) and (HDL are associated with reduced risk)

Question 22

CVD smoking

Answer 22

Smoking cigarettes will increases the risk of suffering with CVD as it now can affect heart rate, platelets, RBC and plasma cholesterol levels. Carbon monoxide in smoke can also impact the oxygen carrying capacity of haemoglobin

Question 23

Treatments of CVD calcium channel blockers

Answer 23

Advantage- lower blood pressure - effective in black people and those aged over 55
Disadvantage- not suitable for people with history of heart disease, liver disease. Side effects are flushed faces, headaches, swollen ankles, dizziness

Question 24

Treatments for CVD beta blockers

Answer 24

Advantage - lower blood pressure - options for people who do not respond to other drugs. Safer to use during pregnancy
Disadvantage - causes side effects such as tiredness, cold hands and feet, slow heart beat, diarrhea and nausea

Question 25

Treatments for CVD satins

Answer 25

Medications used lower the levels of cholesterol in the blood and protects the inside of the artery walls. High levels of cholesterol can lead to fatty deposits buildings up your arteries increasing the risk of heart and circulatory diseases

Question 26

ECG traces

Answer 26

Tachycardia - very fast heart rate
Bradycardia - heart rate is slow
Ventricular fibrillations - not controlled or coordinated
Sinus arrhythmia - normal variation in beating of heart
Flat line - no activity of heart

Question 27

Effects of caffeine in heart

Answer 27

Caffeine can make your heart beta very fast by increasing electrical activity of the SAN
Method -
1. Collect a clean cavity slide
2. Use a pipettes to transfer a large and active Daphnia onto cavity is just covered but remains relatively still
3. Add just enough water to the cavity slide until daphnia is just covered but remains relatively still
4. Places cavity slide with the daphnia on stage of microscope and observe under low power. Beating heart is located in dorsal side just above the gut and in front of brood pouch
5. Uses a stopwatch time 39 seconds and count the numbers of heart beaters in serval periods of 39 seconds using clicker.
6. Repeat investigations
7. Record in table

Question 28

Blood is composed as

Answer 28

-RBC
-WBC
- platelets
-plasma
- 90% water
-amino acids
-glucose
-hormones

Question 29

ABO system

Answer 29

4 main types
- A,B,AB,O
Determined by antigens in surface of red blood cells in torn antigens of RBC membranes causes different blood groups types. Antibodies are proteins produced by immune system that bind stick to antigens.
When antibody binds to the antigens in RBC, causes them to clump together. Called agglutination. Only happens when RBC are present are not compatible with the body system I.e. wrong blood group as they’re rejected

Question 30

Rhesus system

Answer 30

Rhesus antigens on their RBC and are rhesus positive (Rh+) people who have no antigens are rhesus negative (Rh-)

Question 31

Blood types

Answer 31

Letter +/- signs tells us about proteins on their surface if RBC called antigens. A and B and + are name given to 3 types of antigens.
If blood cells doesn’t have + antigens we refer to it as rhesus negative.
If blood cells don’t have A or B antigens we refer to it being in group O