The cardiac cycle

Question 1

2 phase of completing the heartbeat

Answer 1

Diastole: period of relaxation and filling the heart with blood

Systole: contraction and emptying of the heart

Question 2

Heart sounds

Answer 2

“lubb-dubb”
-The “lub” sound occurs when the AV valves close as the ventricles contract
-The “dub” sound occurs when the semilunar valves close when the ventricles relax

Question 3

The heart is a…

Answer 3

myogenic muscle

Question 4

Myogenic muscle means..

Answer 4

it can contract and relax without input from an external source

Question 5

The heart rate is controlled by a special set of cells in the right atrium called the…

Answer 5

sinoatrucak or SA node

Question 6

The SA node is the…

Answer 6

pace maker of the heart. setting a rythem of about 70 beats per minute

Question 7

The SA node send out an electrical impulse to the atria, causing them to contract

The electrical impulse is then passed onto a second node, called the AV node located in the wall of the heartbeat between the right atrium and right ventricle

Question 8

Once AV nose is stimulated, it sends the electrical impulse down HIS bundle to large nerves fibres called Purkinje fibres

The purkinje fibres carry the impulses to the bottom of the ventricles, causing them to contract

Question 9

Heart rate can increase when stressed(fight or flight)
*this increases oxygen supply to cells that need it

Heart rate also affected by: physical activity, caffeine , stress

Question 10

Heart rate is also controlled in the brain

Answer 10

The medulla oblongata region controls heart beat by 2 autonomic nerves:

Vagus nerve: slows down the rate

Cardio-accelerator nerve: speeds up rate

These nerves are connected to the SA node

Question 11

Observing heart beat

Answer 11

Made using an electrocardiograph(ECG)
*Devixe that detects electrical activity of the heart through electrodes placed on the body’s surface

Question 12

Waves of the heart

Answer 12

P wave: monitors arrival contraction caused by stimulus from SA node which creates P wave

this is followed by a small delay as the signal travels to the AV mode

-QRS wave: records ventricular contraction when the electrical stimulus moves via the purkinje fibres

-T wave: indicates that the ventricles have recovered

-changes in electrical current reveal normal or abnormal events of the cardiac cycle

Question 13

Blood pressure

Answer 13

The force exerted by the blood against the walls of the arteries

Question 14

Systolic blood pressure

Answer 14

pressure in the artery when heart is contracting

Question 15

Diastolic blood pressure

Answer 15

pressure is the artery when heart is relaxing

Average human:

120(systole)
——————
80(diastole)

Question 16

Hypertension

Answer 16

Increase in blood pressure in the arteries

-Heart becomes over worked trying to pump against the high pressure
-Arteries get damaged
-Blood clots can occur

Question 17

Arteriosclerosis

Answer 17

-Overtime too much pressure in arteries lead to hardening of the arterial wall
-Caused by age and plaque buildup

Question 18

Atherosclerosis

Answer 18

-Most common form of arteriosclerosis
-Due to plaque that develops on the inner walls of the arteries arriving their diameter
-When plaque buildup occurs in coronary artery, it’s called coronary artery disease

Question 19

Risk factors for CAD

Answer 19

Common factors: family history, increasing age, sex

Other risk factors for CAD:
-high blood pressure
-elevated blood fats
-obesity
-diabetes

Question 20

Cholesterol levels linked to CAD

Answer 20

-Want higher amounts of high density lipoprotein(HDL cholesterol- good cholesterol) and lower amounts of low density lipoprotein (LDL cholesterol- bad cholesterol)
-High LDL cholesterol in the blood contributes to plaque build up on the walls of arteries

Question 21

To lower risk of CAD we can

Answer 21

have better eating habits, and exercise

Question 22

fibre or cellulose lowers cholesterol

Question 23

Heart attack

Answer 23

-Caused by a blockage of an artery that supplies the heart with blood cutting off an O2 supply to cardiac cells
-Heart attack=the death of heart muscle due to loss of blood supply
-symptoms: indigestion, chest pain, pain along the left arm

Question 24

Stroke

Answer 24

-an ischemuc stroke occurs when a clot in a blood vessel blocks the flow of blood to the brain

-a hemorrhagic stroke occurs when a blood vessel in the brain bursts and blood flows into the surrounding brain tissue

-both kill brain cells and can lead to permanently damage

-treatment must being immediately to be effective. includes clot busters, surgery, and non surgical procedures

-symptoms vary depending on area of brain affected

Question 25

treatments of coronary artery disease

Answer 25

1. lifestyle changes(exercise, healthy diet, smoking)
2. Angioplasty
   3.Coronary bypass surgery

Question 26

Angioplasty

Answer 26

-opening up a blocked artery by inflating a small balloon at the point of blockage

-balloon presses plaque build up against the artery walls

-a stent is then inserted to ensure the artery remains open

Question 27

Coronary bypass surgery

Answer 27

-During a bypass, a section of healthy artery or vein from another part of the body is used to create a new pathway for blood to flow around a blockage

-Depending on the number of blockages, surgeons may perform a double, triple, or quadruple bypass

Question 28

Aneurysm

Answer 28

-a buldge in an artery due to a weakened area of the arterial wall
-blood pressure can cause the aneurysm to grow larger over time
-if it bursts, internal bleeding can be fatal
-treatments include surgery to remove damaged portion and replacement with a patch or graft made of synthetic material

Question 29

Heart valve disease

Answer 29

-regurgitation l: when a valve doesn’t close completely and blood flows backward instead of forward
-stenosis m: when the valve opening becomes narrowed from thickening or scarring

-causes include ageing,previous heart attack or infection
-surgeons may repair the valve or replace it with a human, animal, metal or plastic alternative

Question 30

Arrhythmia

Answer 30

-a problem with the sped or rythem of the heartbeat
-can lead to induffiebt blood flow for he brain or other organs
-may be treated with medications or surgery to implant an artificial pacemaker

Question 31

Congenital heart defect

Answer 31

-present since birth: include problems in the walls dividing heart chambers, in valves, and in structure of heart blood vessels
-surgeons can often successfully repair or reduce damage
-diagnosed by Ct or MRI scans

Question 32

Leukaemia

Answer 32

-a cancer of the white blood cells
-myeloid leukaemia involves too many immature leukocytes that aren’t able to fight infection
-lymphoid leukaemia involves too many lymphocytes that are unable to perform their immunity role both can be acute or chronic
-treatments include blood transfusions,chemo, or bone marrow transplant