Cardiovascular and respiratory system (1)

Define Medulla oblongata

Define Medulla oblongata

The medulla oblongata is where the cardiac control centre is held

Define chemoreceptors

Chemoreceptros sense chemical changes during excercise (found in the carotid artery)

Define baroreceptors

Baroreceptors detect blood pressure the nerves attached to the arterial wall

Define proprioreptors

Proprioceptors located in muscles, tendons and joints provide information about body movement

Define anticapatory rise

anticapatory rise is the release of adrenaline from the adrenal gland causing an increase in heart rate prior to excercise

Define Stroke volume

Stroke volume is the amount of blood pumped out by the hearts ventricles in each contraction

what is the resting stroke volume

70ml

What are factors effecting cardiac output

Venous return

Define venous return

Venous return is the amout of blood returning to the heart via the veins (if venous return increases so does stroke volume)

What is starlings law ?

increased venous return -} greater diastolic filling of the heart -} cardiac muscles stretched -} more force of contraction -} increase injection fraction.

what is ejection fraction

The amount of blood left in the left ventricle after each ventricle

Define Cardiac output

Cardiac output is the volume of blood pumped out by the heart ventricles per minute =(stroke volume x heart rate)

how do you calculate maximal heart rate (roughly)

220 - age = maximum heart rate

why does cardiac output incease due to excercise ?

Cardiac output increases due to an increase in stroke volume and heart rate. cardiac output will increase as the intesnity of excercise increases.

what does stroke volume do when 40-60 % of maximum output is reached ?

it plateaus as the ventricles do not have enough time to refill fully, so they are unable to pump out as much as possible

what does CHD stand for ?

Coronary heart disease

Define angina

Angina is pain and discomfort in the chest due to athereoscrolosis blocking up arterioes.

What is atherosclerosis ?

Where vital areteries around the heart become blocked by gradual build up of fatty deposits

Define blood pressure

Blood pressure is the amount of force exerted by the blood against the blood vessel wall

Define LDL (low density lipopriotiens)

LDL’s transport excess cholesterol in the blood to the tissues these are classed as ‘bad’ and are linked to CHD

Define HDL (High density lipopriotiens)

HDL’s Transport excess cholesterol in the blood back to the liver where it is broiken down these lower the risk of heart disease.

Define Cardiovascular drift

Cardiovascular drift is the steady increase in heart rate it occurs after 10 minutes of excercise.

How does cardiovascular drift occur ?

A progressive decrease in stroke volume and arterial blood pressure, combined with a slow rise in hear rate

Why does cardiovascular drift occur ?

A reason for this may be because when we sweat a portion of the sweat comes from the plasma volume. this decrease of plasma volume leadsd to a reduce in venous return and stroke volume.

How do we stop Cardiovascular drift

maintain high fluid consumption before and during excercise.

Characteristics of Veins

Veins have thiner muscle/elastic layers they have valves and wider lumen

Characteristics of arteries

Ateries have more of an elastic layer to cope with high pressure aa smaller lumen and smooth inner layer

Characteristics of capillaries

are on cell thick , to allow the exchange of nutriences with the tissues to take place by diffusion

How is blood pressure measured

Blood flow x resistance

Define systolic pressure

When the heart contracts if forces blood out under high pressure

Define diastolic pressure

Diastolic pressure is as the ventricles relax

What are the 3 venous return mechanisms (5)

The skeletal muscle pump

The respiratory pump

Pocket valves

Define the skeletal muscle pump

The skeletal muscle pump is when a muscle contacts and relex they change shape this causes them to press on nearby veins pumping it back to the heart

Define the respiratory pump

When muscles contract and relax during breathing pressure changes in the thoracic cavity theses changes in pressure compress veins

Define pocket valves

Pocket Valves allow blood to flow in one direcction, once blood flows through these valves they close

Define Vascular shunt

Diverting blood to active aways and diverting away from inactive areads, occurs through vascoconstriction

Why is redistribution of blood important

• increases the supply of oxygen to working muscle

• remove waste products from the muscles, such as carbon dioxide

• ensaure more blood goes to the skin during excercise to regulate temprature

• direct more blood to the heart as it is a muscle and requires extra oxygen during excercise

Define A-VO2 Diff (END OF HEART)

This is the difference between the ocygen content ofd the arterial blood arriving at the muscles and the venous blood leaving the muscles.

Define Tidal volume

Tidal volume is the volume of air inspired or experied per breath

Define the inspiratory reserve volume

The extra amount of air inspired

Define expiratory reserve volume

The amount of air expired

Define residual volume

The amount of blood left in the lungs after a breath

what measures the volume of air we breathe in or out

Spirometer