The Heart

Key Components

PULMONARY VEIN- Carries oxygenated blood from the lungs to the heart

PULMONARY ARTERY- Carries deoxygenated blood from the heart to the lungs

AORTA- Carries oxygenated blood from the heart to the rest of the body

VENA CAVA- Carries deoxygenated blood from the rest of the body to the heart

BICUSPID VALVE- Located on the left side of the heart

TRICUSPID VALVE- Located on the right side of the heart

SEMI-LUNAR VALVE- Found in both sides of the heart

SEPTUM- Separates the left and right side of the heart

Sound of the heart

1st NOISE- 'lub'

• AV valve snaps shut as the ventricles start to contract

2nd NOISE- 'dup'

• Semi-Lunar valves closing as the venntricles begin to relax

The heart is a double- circulatory system

• Blood passes through the hear twice
• Once through the systemic circuit- to the body a back via the aorta and vena cava
• Once through the pulmonary circuit- to the lungs and back via the pulmonary artery and the pulmonary vein

Thickness of walls of the heart

• Right side of the ventricle walls are thinner than those of the left side
• Right ventricle pumps blood to the lungs so doesnt travel far and so not a lot of pressure needs to be created
• However, the left ventricle has further to travel as it pumps blood to the rest of the body, the thicker walls generate a high pressure for the blood to travel at

Faulty Aortic Valve affect blood flow

• Valves prevent backflow of blood
• A faulty aortic valve would cause a backflow of blood into the left ventricle
• This results in less blood being pumped around the the body so less oxygen

Oxygenated and Deoxygenated Blood in the Heart

Left side of the heart- oxygenated

Right side of heart - deoxygenated

THICK MUSCULAR WALLS

• Helps to withstand high pressure
• supports artery
• able to contract and relax to cope with pressure

ELASTIC TISSUES

• Stretch and expand during contraction
• recoil during relaxation
• Flexible
• Aid in vasodilation/ vasoconstriction

SMALL LUMEN

HAVE VALVES

• Prevent backflow of blodd

SURROUNDED BY SKELETAL MUSLCES

• Contract to aid with blood flow

LARGE LUMEN

CAN EXPAND AND RECOIL

ONE CELL THICK

• Aid with diffusion of gases and waste products
• Allows for gaseous exchange to occur

HOW STRUCTURE OF ARTERY HELPS TO MAINTAIN BLOOD PRESSURE

• Lumen of artery inctrases with the increased flow of blood
• In Systole- Walls of artery stretch and expand to prevent pressure from increasing in the artery
• In Diastole- Walls of the artery recoil
• When relaxed the lumen of artery returns to normal to prevent a fall in blood pressure
• If blood pressure is too low then the artery walls will contract to make the lumen smaller- this increases the blood pressure
• thick layer of muscle in the wall helps artery to withstand high pressure
• The muscle is able to contract and relax in order to change the lumen (size)

HOW THE TISSUES OF ARTERY HELP TO MAINTAIN BLOOD PRESSURE DURING SYSTOLE

• Systole is the contraction of the heart
• Lumen of artery increased with the increased flow of blood/ blood pressure
• The walls stretch to prevent pressure from increasing in the artery which could lead to a rupture

HOW THE TISSUES OF THE ARTERY HELP TO MAINTAIN BLOOD PRESSURE DURING DIASTOLE

• Diastole is the relaxation of the heart
• The walls of the artery recoil
• Lumen of artery decreases (returns to normal) to prevent a fall in blood pressure

HOW THE MUSCLE OF THE ARTERY HELPS TO MAINTAIN BLOOD PRESSURE

• If blood pressure is low, the muscle will contract and the lumen will become smaller
• if blood pressure is high, the muscle will relax and the lumen will become bigger

HOW ARTERIOLES ARE ABLE TO ALTER BLOOD PRESSURE

• Walls of arteries contain smooth muscles
• Vasomotor centre in medulla oblongata alerts sympathetic nervous ststem
• sympathetic nervous system is stimulated
• This causes the smooth muscle to contract and cause vasoconstriction
• When sympathetic nervous system is not stimulated the smooth muscle relaxes and causes vasodilation

HARDENING OF ARTERIES AFFECTS BLOOD FLOW

• Arteries become less elastic
• They then strethc and recoil less
• Less able to propel the blood along
• This causes a reduced blood flow around the body

FAT DEPOSITED IN ARTERIES

• Narrower arteries as the lumen becomes smaller
• reduced blood supply to heart and therefore a reduced oxygen supply

STUCTURE

Arteries

• Have no valves
• Have thicker walls
• Have more elastic
• More muscle tissue

Veins

• Have valves
• Have large lumen
• Have less elastic
• Have thinner walls

FUNCTION

Arteries

• Carry blood away from the heart
• Carry mostly oxygenated blood
• Transport blood under high pressure
• Help to maintain blood pressure

VEINS

• Carry blood to the heart
• Carry mostly deoxygenated blood
• Transport blood under low pressure
• Veins do not have to maintain blood pressure

1. Take resting pulse rate/ heart rate for one minute

2. Carry out cardiovascular fitness for a specified amount of time

3. Immediately after exercise take pulse rate/ heart rate for one minute

4. Take pulse rate/ heart rate every minute until it returns to resting

5. The quicker the time for pulse rate/ heart rate to return to resting the fitter the person is

VENTRICULAR DIASTOLE (RELAXING)

• Ventricles are relaxed
• Blood begins to enter atria
• Increased blood in atria causes a rise in pressure
• When blood has nearly fille atria the increased pressure causes the AV valve to open slightly
• This allows blood to drip into ventricle
• Semi-lunar valves remain closed
• Low pressure

ATRIAL SYSTOLE (CONTRACTING)

• Atria contracts
• Blood flows into the ventricles
• Increased pressure

VENTRICULAR SYSTOLE (CONTRACTING)

• AV valves close
• Ventricles contact blood is pushed up and out at high pressure
• Semi-lunar valves open

Increased levels of carbon dioxide in blood

Chemoreceptors in the carotid arteries detect high levels of carbon dioxide

Impulses sent to medulla oblongata

This counteracts a change where the Sympathetic nervous system is alerted

An increased frequency of impulses are sent to the SA node in the right atria

If levels are restored to normal

Impulses sent to parasympathetic nervous system- increased frequency of impulses sent to SA node in the right atria

OR

reduced frequency of impulses along the sympathetic nervous system

• Electrical impulses enter both atria to the SA node from the brain
• Impulses move through the atria causing it to contract- atrial systole
• Impulses reach the bottom of the atria to the AVN node- this leaves a delay so the atria can finish contracting and so the blood flow into the ventricles
• After the delay hs finished the impulse enters the AVN bundle and travels down the purkyne fibres and then down thr inter-ventriclular system
• At the base of the septum the impulses travel along the ventricles and at the apex, the ventricles contract which pushes the blood up to the major arteries

• An ECG detects abnormal heartbeats
• It detects the electrical signals of the heart
• Records the hearts rhythm

BRADYCARDIA

• Heart rate is slower than normal
• Symptoms- Fatigue, dizziness

TACHYCARDIA

• Heart rate is faster than normal
• Symptoms- Pain, drug withdrawal

VENTRICULAR FIBRILATION

• Uncontrollable heart rate that causes heart to beat at the wrong time
• Cause heart attacks and organ shutdown or if fatal death

P- Atrial Systole

QRS- Ventricular Systole

T- Ventricular Diastole

P- Atrial Systole

QRS- Ventricular Systole

T- Ventricular Diastole

• 18 year old- 120/80 mm Hg
• 20 year old FEMALE- 123/80 mm Hg
• 20 year old MALE- 125/85 mm Hg
• 40 year old FEMALE- 133/85 mm Hg
• 40 yearl old MALE- 135/85 mm Hg

Measuring blood pressure

• Manual Sphygmomanometer
• advantages- gives accurate reading
• disadvantages- need training/ human error

• Digital Sphygmomanometer
• advantages- quick/easy/ dont need training/ less room for human error
• disadvantages- can malfunction/ not as accurate

Function of lungs

to swap gases between the atmosphere and thr blood, to do this the lungs need to be

1. thin and have a large surface area for gases to diffuse across

2. have a way of getting air in and out the lungs

Components of Lungs

• Trachea
• Bronchus
• Bronchioles
• Alveoli
• Intercostal Muscles
• Diaphragm
• Ribs

1. Diaphragm Contracts and moves down

2. Intercostal muslces contract and raise the ribs

3. Volume of Chest cavity increases

4. Internal lung pressure decreases and drops below atmospheric pressure down pressure gradient

5. Air moves into lungs

1. Diaphragn relaxes and moves up

2. Intercostal muscles relax and ribs fall

3. Volume of chest cavity decrease

4. Internal lung pressure increases above atmospheric pressurre

Capillaries

• Allows carbon dioxide and oxygen to diffuse in an out

One cell thick

• Shorter diffusion pathway means quicker diffusion rate

Blood capillaries wrapped around alveoli

• Gives it a larger surface area

Moisture

• Allows for oxygen to dissolve and stops alveoli from cracking and collapsing

Shape

• Allows for a larger surface area to aid in gas exchange

• the alveoli are surrounded by a network of blood vessels that carry blood to alveoli
• lots of alveoli and so a larger surface area
• blood vessels surround thr alveoli
• capillaries and alveoli are very thin so aid in diffucsion as there is a short diffusion pathway
• carbon dioxide is at a higher concentraction in the blood than alveoli
• carbon dioxide leaves the blood and enters the alveoli by diffusion

C-shaped cartilage

• very protective and allow maximum air to enter and leave

Cilia

• hair like forms which remove bacteria and dust particles by wafting away the mucus to prevent damage to lungs

Glands

• goblet cells secrete mucus to moisten air taken in and also traps bacteria and dust particles before they enter the lungs

Consists of a chamber filled with oxygen that floats on a tank of water

A person breathes from a disposable mouthpiece attached to a tube connected to the chamber of oxygen

Breathing in, takes oxygen from the chamber, which then sinks down

Breathing out, pushes air into the chamber which then floats up

• TIDAL VOLUME- volume of air moved in and out of the lungs during breathing when at rest
• VITAL CAPACITY- Largest volume of air that can be moved in and out of the lungs in any one breath
• RESIDUAL VOLUME- Volume of air that always remains in the lungs
• DEAD SPACE- Air in bronchioles, bronchi and trachea
• INSPIRATIORY RESERVE VOLUME- How much more air can be breathed in the over and above the normal tidal volutme when you take in a big breath
• EXPIRATORY RESERVE VOLUME- How much more air can be breathed out over and above that is breathed out in a tidal volume breath