Cardiovascular and respiratory systems

Question 1

Define the pulmonary and systemic circuit

Answer 1

Pulmonary - carries deoxygenated blood through the pulmonary artery to the lungs and pulmonary vein back to the heart (right side)

Systemic - carries oxygenated blood through the aorta to the body and vena cava back to the heart (left side)

Question 2

Explain the conduction system

Answer 2

1) Sino atrial node - Generates the electrical impulse and fires it through the atria walls causing them to contract
2) Atrio ventricle node - Collects the impulse and delays it for 0.1 secs, to allow the atria to finish contracting. Then releases the impulse to the bundle of his
3) Bundle of his - Splits the impulse into 2, to be distributed through each separate ventricle
4) Bundle branches - Carry the impulse to the base of each ventricle
5) Purkyne fibres - Distributes the impulse through the ventricle walls causing contraction

Question 3

Define myogenic

Answer 3

Capacity of the heart to generate its own electrical impulse, using cardiac muscle to contract.

Question 4

what are the 3 phases in the cardiac cycle

Answer 4

Diastole - Relaxation phase. As the atria and ventricles relax, they expand drawing in blood into the atria. The pressure in the atria increases opening AV valves, blood enters ventricles. SL valves close to prevent back flow of blood.

Atrial systole - atria contracts, forcing remaining blood into the ventricles

Ventricular systole - ventricles contract, increasing the pressure closing AV valves to prevent back flow into the atria. SL valves are forced open as blood is ejected from the ventricles into the aorta and pulmonary artery.

Question 5

Define heart rate and how to calculate the maximal HR

Answer 5

Number of times the heart beats per min

220 - age

Question 6

Define stroke volume

Answer 6

Volume of blood ejected from the left ventricle per beat

approximately be 70ml

Question 7

Define cardiac output and how to calculate Q

Answer 7

Volume of blood ejected from the left ventricle per min

HR x SV

Question 8

Define bradycardia

Answer 8

A resting HR below 60 bpm

Question 9

What is venous return

Answer 9

Return of the blood to the right atria though the veins.

Question 10

State a few HR responses to exercise

Answer 10

Rapid increase in HR will increase blood flow and oxygen delivery.
Release of hormone adrenaline
Oxygen supply meets demand
Decrease in HR as recovery enters

Question 11

State a few stroke volume responses to exercise

Answer 11

Increase venous return
Frank starling mechanism
Increased HR towards maximal intensities

Question 12

What is the Fank starling mechanism

Answer 12

Increased venous return leads to an increased stroke volume, due to increased stretch of the ventricle and force of contraction

Question 13

what is the ccc

Answer 13

cardiac control centre

Receives information from the sensory nerves and sends direction through motor nerves to change HR

Question 14

What are the control mechanisms in the CCC

Answer 14

1) Neural control :

chemoreceptors - detects chemical changes in the blood stream
Proprioceptors - informs ccc of motor activity
Baroreceptors - inform ccc of increased blood pressure

2) Intrinsic control :

Temperature changes will affect the viscosity of blood and speed of nerve impulse transmissions
Venous return affects the stretch in ventricle walls, contractions and SV

3) Hormonal control :

Adrenaline and noradrenaline are released increasing SV and electrical activity (HR)

Question 15

what is the sympathetic nervous system

Answer 15

responsible for increasing HR during exercise

Question 16

what is parasympathetic nervous system

Answer 16

responsible for decreasing HR during recovery

Question 17

what is the vascular system

Answer 17

Dense work of blood vessels and blood. Ensures oxygen and nutrients are delivered to all cells for energy production and waste is removed.

Question 18

Vascular system is of blood vessels. Explain the 3 main types of blood vessels

Answer 18

1) Arteries - smooth muscle and elastic tissue to smooth pulsating blood flow.
Arterioles - smooth muscle allowing vessels to vasodilate and vasoconstrict to regulate blood flow and blood pressure.

2) Capillaries - bring the blood slowly into close contact with muscle and organ cells for gaseous exchange.
3) Veins and venues - small layer of smooth muscle allowing them to ventilate and venoconstrict to maintain slow flow of blood. Veins have a one way pocket valves

Question 19

What are the mechanism of venous return

Answer 19

1) Pocket valves - one way valves in veins
2) Smooth muscle - venoconstricts to aid the movement of blood
3) Gravity
4) Muscle pump - skeletal muscle contract compressing veins to squeeze blood back to the heart
5) Respiratory pump - During inspiration and expiration, a pressure difference between thoracic and abdominal cavity is created, squeezing blood back to the heart.

After exercise we may feel light headed - blood pooling - accumulation of blood in veins due to gravitational pull and lack of venous return.

Question 20

What is vascular shunt mechanism

Answer 20

redistribution of cardiac output around the body from rest to exercise, increasing blood flow to skeletal muscles by the vasodilation and vasoconstriction of arterioles and precapillary sphincters dilating and constricting.

Question 21

Explain the vasomotor control centre

Answer 21

Is located in the medulla oblongata and is responsible for the distribution of cardiac output. Receives information from chemoreceptors and baroreceptors.

At rest - arterioles and pre capillary sphincters are stimulated to vasoconstrict, listing blood flow to muscle cell. During exercise, they vasodilate to increase blood flow

At maximal intensities, up to 88% of cardia output is redistributed.

Question 22

Define alveoli

Answer 22

Clusters of tiny air sacs covered in a dense network of capillaries which together serve as the external site for gaseous exchange.

Question 23

Define gaseous exchange

Answer 23

Movement of oxygen from the alveoli into the blood stream and carbon dioxide form the blood stream into the alveoli.

Question 24

Define breathing rate

Answer 24

Number of inspirations or expirations per min (approx 12-15 breaths/min)

Question 25

Define tidal volume

Answer 25

Volume of air inspired or expired per breath (approx 500 ml)

Question 26

What is haemoglobin

Answer 26

Ion rich protein in red blood cells which can chemically combine with 4 oxygen molecules to form oxyhemoglobin

Question 27

Define minute ventilation and how is it calculated

Answer 27

The volume of air inspired or expired per min

TV x breathing rate

Question 28

Explain the mechanics of inspiration at rest

Answer 28

External intercostals contract lifting the rib cage and sternum up. The diaphragm separates the thoracic and abdominal cavity, contracts and flattens.

Question 29

Explain the mechanics of inspiration during exercise

Answer 29

In addition to the mechanics at rest. The sternocleidomastoid and pectorals minor are recruited to give a larger force of contraction. Creating a greater up and outward movement, increasing volume and decreases pressure inside thoracic cavity. Increases depth of breathing

Question 30

Explain the mechanics of expiration at rest

Answer 30

External intercostals relax, lowering rib cage and sternum down and in. The diagram relaxes and returns to its dome shape.

Question 31

Explain the mechanics of expiration during exercise

Answer 31

Internal intercostals and rectus abdominis are recruited. creating a greater down and inward movement of the rib cage and sternum.

Question 32

Define partial pressure

Answer 32

Pressure exerted by an individual gas held in a mixture of gases

Question 33

Define diffusion

Answer 33

The movement of gases across a membrane down a gradient from an area of high pressure to low pressure

Question 34

Define diffusion gradient

Answer 34

The difference in areas of pressure from one side of a membrane to the other

Question 35

What is the oxyhemoglobin dissociation curve

Answer 35

A graph showing the relationship between pO2 and percentage saturation of haemoglobin.

Question 36

Define Bohr shift

Answer 36

A move in the oxyhemoglobin dissociation curve to the right caused by increased acidity in the blood stream.