The Cardiovascular Respiratory System

The Cardiovascular System

Components

The cardiovascular system consists of:

• The Heart

• Blood Vessels

– Arteries and Arterioles

– Veins and Venules

– Capillaries

• Blood

Functions

• Circulate blood to all parts of the body

• Transport water, oxygen and nutrients to cells

• Remove wastes, including carbon dioxide, from cells

• Maintain body temperature-known as homeostasis.

• Helps fight disease (WBCs)

The Heart

• Hollow muscular structure made from cardiac muscle.

• It is the size of a clenched fist.

• It’s located in the centre of the chest, behind your sternum (slightly to the LHS).

• It is a pump which pushes blood around the body.

Heart Anatomy

• Composed of four chambers:– Two atria (L & R): Receive blood from the body

– Two ventricles (L & R) : Pump blood back out into the body.

• The septum divides the heart into two pumps:1.Left side- Oxygen rich (red coloured)- From the lungs to

the body.

2.Right side- De-oxygenated(blue coloured)- From the body to the lungs.

Pulmonary & Systemic Circuits• The Pulmonary Circuit:

Deoxygenated blood circulates into the pulmonary artery to the lungs to pick up O2

and transport back to heart

• The Systemic Circuit:

Oxygenated blood from the heart circulates through the arteries around the body to the various tissues and back to the heart

Heart Valves

• Blood pumped does not mix as valves located between atria and ventricles only allow blood to move in one direction

The “Pulse”

• ‘Pulse’: is a pressure wave that results from the thrust that occurs when the ventricles of the heart contract

• The pulse can be felt in 4 locations around the body:– Temporal (Temple)

– Carotid (Side of Neck)

– Radial (Base of thumb)

– Femoral (Groin)

Heart Rate

• Your heart beats over 100,000 times per day.

• Heart rate (HR) is measured in bpm.

• The sinoatrial node is located in the R atrium and generates an electrical signal which causes the heart to contract.

Factors Affecting HR

• Gender- female may be 5-10 bpm faster due to smaller heart size.

• Age and Size- higher at birth compared to adulthood• Body size• Fitness- lower HR due to less work/resistance• Body Position- 5-10 times less when lying down • Food Digestion- increase during eating• Emotion- can increase by 50bpm when stressed,

excited or nervous

Blood Vessels

• Blood vessels are designed to deliver blood to the organs & tissues that require it.

• Each connecting blood vessel will be smaller than the previous but will have a larger cross-sectional area.

• There are three main types:1. Arteries and Arterioles

2. Veins and Venules

3. Capillaries

1. Arteries and Arterioles

• Carry oxygen-rich blood from heart to body.

• Walls are elastic and expand with each heart beat. Contain a muscle component.

• Arteries further reduce in size to become arterioles as the network of blood vessels work their way into the depths of the body.

• The Coronary Artery supplies the hearts chambers with oxygen and nutrients.

2. Veins and Venules

• Veins carry deoxygenated blood back to the heart.

• The deoxygenated blood has little oxygen and contains high amounts of waste products.

• Veins have no pulse, blood flow is steady and constant.• The walls of veins are thin and not as elastic as artery

walls.• The return of blood to the heart depends on contraction of

skeletal muscle- which squeezes the blood as they contract.

• One way valves working against gravity and prevent backflow of blood to organs and muscles.

3. Capillaries

• Smallest blood Vessels in body.

• Exchange of nutrients and waste between the blood and the body cells occurs in the capillaries .

• Heat from cells is also absorbed into blood through the capillaries.

• When you begin to exercise capillaries dilate to allow increased blood flow.

• Wall only one cell thick.

• A long term exercise program may increase the number of capillaries supplying blood to muscles, allowing an increased oxygen supply to muscle and removal of wastes.

Importance of cooling down after exercise

• Blood Pooling may occur after exercise if an adequate cool down is not performed

• During exercise blood flow can increase from 5L (resting) to 30L per minute

• During the cool down the muscle pump system gradually returns the excess blood to the heart- reducing the blood flow

• If this does not occur then blood pools in the legs

Removal of heat from body

• Blood carries heat produced by cells to the surface of the skin

• Exercise causes blood vessels to vasodilate close to the skin surface so the heat can radiate outwards

• This gives the skin a red colour

• For this to work effectively the body needs lots of water to carry the heat and allow perspiration to occur

Blood• Only body tissue that is liquid • It is used to transport various

substances to the organs and other tissues.

• Blood cells make up 45% of the blood volume

• While plasma makes up the other 55% • The three types of blood cell are:

1. Red blood cells 2. White blood cells 3. Platelets

Blood Cells1. Red Blood Cells (RBC):

• Contain haemoglobin which carries oxygen molecules and gives the red colour

• Produced in bone marrow

• 120 day lifespan, 99% of all blood cells

• Concave disc shape

2. White Blood Cells (WBC):

• Part of the immune system (fight infection)

• Called leukocytes and form pus

• Produced in bone marrow and lymph tissue

• 10 day lifespan

Blood Cells3. Platelets

• Clot blood to stop bleeding

• Produced in bone marrow

Plasma:

• Liquid part of the blood

• Also contains- Soluble food molecules, waste products, hormones and antibodies.

• Transports and assists in the removal of wastes

Blood Pressure

• As blood is pumped out of the heart it creates pressure within the arteries which is known as blood pressure (BP).

• It measures the pressure exerted by the blood against the walls of the arteries

• It is used to assess the functioning or “healthiness” of the heart and blood vessels.

Blood Pressure

• Systolic BP: is the pressure created when the blood is pumped out of the left ventricle and is the top figure in BP measurement.

• Diastolic BP: is the pressure created as the heart relaxes and refills and is the bottom figure in BP measurement.

• Normal is 120/80; High 180/100; Low 80/60.

Factors Affecting BP

• Gender- women prior to menopause generally have a lower BP than men.

• Time- it is lower during sleep and higher after meals.

• Stress- being stress, nervous or scared will increase BP. Long term stress can cause hypertension (chronic high BP).

Stroke Volume (SV) & Cardiac Output (Q)

SV: – The amount of blood pumped into the systemic circuit

with one heart beat. Avg. Adult female = 60mlAvg. Adult Male = 80ml

– In an endurance trained male under maximal conditions it could reach 160ml!

Q:– The amount of blood the body pumps in one minute.

Around 5 litres at rest, up to 30 litres under maximum effort.

– Q= SV x HR

Arteriovenous oxygen difference (AVO2)

• Is the amount of oxygen taken up by the tissues of a muscle.

• It is the difference between the oxygen in the arteries compared to the veins.

• Rest: Muscles use 6mL per 100mL of oxygen

The Cardiovascular System & Physical Activity

• Acute Responses:

– Increased HR

– Increased SV

– Increased Q

– Increased BP

– Increased blood flow and blood vessel diameter

– Increased body termperature

– Increased AVO2

– Increased coronary circulation

The Cardiovascular Respiratory System

The Respiratory System

Why do we need to breath?

• Movement, growth and reproduction all require energy.

• Energy must be taken from the food we eat and this energy transfer is called tissue respiration.

• This involves the use of oxygen and produces carbon dioxide.

Role of Respiratory System

• Brings air from the atmosphere into the lungs

• Transfers oxygen into the blood

• Removes carbon dioxide from the blood

• Expels heat and water vapour in the air breathed out

• Allows the vocal cords to create speech as air is breathed out

• Ventilation- is the movement of air into and out of the respiratory system.

Components

• The Pleura:

– A membrane which covers each lung

– The gap between the membrane and lung contains fluid which allows the lungs to expand/contract with minimal friction

• The Diaphragm:

– Moves up and down to assist breathing

– Smooth involuntary muscle

Inspiration

• Breathing in

• Diaphragm contracts (involuntary), it moves downwards, enlarging the chest cavity.

• This creates an area of low pressure so that the air rushes inside.

• Air moves from high to low pressure.

Expiration• Breathing out

• Occurs when the diaphragm relaxes and the chest cavity returns to its ‘at rest’ state.

• The air pressure inside the chest cavity becomes higher.

• Air is forced out of the lungs.

• Inspiration: ribs lift up and out, volume of lungs increase, diaphragm contracts, air pressure drops, air forced in.

• Expiration: volume of lungs decreases, diaphragm relaxes, ribs lower, air pressure increases, air forced out.

Gas Exchange in the lungs

• The alveolar capillaries have very thin walls which aid diffusion.

• This allows oxygen to diffuse from high pressure in the alveoli to low pressure in the capillaries.

• Carbon dioxide is also able to move from high pressure in the capillaries to low pressure in the alveoli.

Respiratory Volumes & Capacities• Respiratory Rate: Amount of times you breathe per minute

– Avg resting adult = 12-18times per min

• Tidal Volume: The amount of air breathed in or out during normal respiration.

– Avg adult = 0.5litres

• Vital Capacity: The largest volume of air that can be expired after a maximal inspiration.

• Residual Volume: The amount of air left in the lungs after a maximal expiration.

• Ventilation: Amount of air inspired per minute.

– Ventilation= tidal volume X respiratory rate.

– For an average adult

• Ventilation = 0.5L x 12 breaths/min = 6L/min

Measuring Lung Volume

Maximal Oxygen Uptake (VO2 Max)

• The VO2 Maximum is the maximal amount of oxygen that can be taken into the body and transported to and used up by the muscles during exercise.

• It is the best indicator of how aerobically fit you are.

• It is the largest amount of oxygen that you can use per minute.

Maximal Oxygen Uptake (VO2 Max)

• It is determined by your max HR, stroke volume and AVO2 difference.

• Tests such as the 20m shuttle run, 12 minute walk/run and the Repco 7 min ergometer cycle test all predict VO2.

• An accurate test must be completed in a lab.

The Respiratory System & Physical Activity

• Acute Responses:

– Increased RR

– Increased tidal volume

– Increased ventilation

– Vital capacity remains the same

– Increased O2 uptake

– Increased effort intercostal muscles and diaphragm