Part 1.2 Cardiovascular And Respiratory Systems

Question 1

What do proprioreceptors sense?

Answer 1

That movement has increased in the muscles

Question 2

What do chemoreceptors sense?

Answer 2

Changes in chemicals in the muscles and blood. These changes include increased CO2, lactic acid and increased acidity in the blood

Question 3

What do baroreceptors sense?

Answer 3

They are sensitive to stretch within the blood vessel walls, they detect increased blood pressure

Question 4

Hormonal control

Answer 4

Increase of adrenaline released into blood (anticipatory rise), stimulates the SA node to increase heart rate and therefore stroke volume

Question 5

Intrinsic control

Answer 5

Durning exercise, temp increases which increases the speed of nerve impulses which in turn increase heart rate.

Question 6

What does intrinsic control increase?

Answer 6

Venous return, myocardial stretch, EDV, SV, temperature, nerve impulses, HR, CO

Question 7

Mechanisms that aid return of blood to right atrium (venous return)

Answer 7

Pocket valves - force blood in one direction
Skeletal muscle pump - veins are squeezed between skeleton and muscles in contraction and relaxation phases
Respiratory pump - more pressure in abdominal cavity squeezes veins
Smooth muscle - (in walls of veins push blood (smooth = less friction))
Gravity - blood pooling (only mention in 5 marker)

Question 8

What is the pathway of blood

Answer 8

• Vena Cava
• Right atria
• Right AV valve (tricuspid)
• Right ventricle
• Pulmonary artery
• Lungs (becomes oxygenated)
• Pulmonary vein
• Left atria
• Left AV valve (bicuspid)
• Left ventricle
• Aorta
• Oxygenated blood goes to organs and muscles

Question 9

Mechanisms of venous return

Answer 9

• Pocket valves. One way valves located in the veins which prevent the backflow of blood
• Smooth muscle. The layer of smooth muscle in the vein wall venoconstricts to create venomotor tone which aids the movement of blood
• Gravity. Blood from the upper body, above the heart, is helped to return by gravity
• Muscle pump. During exercise, skeletal muscles contract compressing the veins located between them, squeezing the blood back to the heart
• Respiratory pump. During inspiration and expiration, a pressure difference between the thoracic cavity and abdominal cavity is created, squeezing the blood back to the heart. As exercise increases respiratory rate, the respiratory pump is maximised.

Question 10

Mechanics of inspiration at rest

Answer 10

• external intercostals contract, lifting the rib cage and the sternum up and out
• the diaphragm contracts and flattens
• volume of thoracic cavity increases
• pressure in the lung tissue decreases

Question 11

Mechanics of inspiration during exercise

Answer 11

• external intercostals, diaphragm, sternocleidomastoid and pectoralis minor contract with more force
• ribs and sternum lift up and out further
• volume of thoracic cavity increases more than at rest
• pressure in the lung tissue decreases more than at rest

Question 12

Mechanics of expiration at rest

Answer 12

• external intercostal muscles relax, lowering the rib cage and sternum down and in
• the diaphragm relaxes and returns to its dome shape
• volume in thoracic cavity decreases
• pressure in the lung tissue increases

Question 13

Mechanics of expiration during exercise

Answer 13

• external intercostals and diaphragm relax
• internal intercostals and rectus abdominis contract
• ribs and sternum move down and in more
• volume in thoracic cavity decreases more than at rest
• pressure in the lung tissue increases more than at rest

Question 14

Explain what happens during diastole

Answer 14

• as the atria and then ventricles relax, they expand drawing blood into the atria
• the pressure in the atria increases opening AV valves
• blood passively enters the ventricles
• SL valves are closed to prevent blood from leaving the heart

Question 15

Explain atrial systole

Answer 15

• the atria contract, forcing remaining blood into the ventricles

Question 16

Explain ventricular systole

Answer 16

• the ventricles contract, increasing the pressure closing the AV valves to prevent backflow into the atria
• SL valves are forced open as blood is ejected from the ventricles into the aorta and the pulmonary artery

Question 17

define heart rate and give a resting value

Answer 17

The number of times the heart beats per minute (resting HR typically 72bpm, trained = 50bpm)

Question 18

Define stroke volume and give a typical resting value

Answer 18

The volume of blood ejected from the left ventricle per beat (resting SV approx 70ml, trained = 100ml)

Question 19

Define cardiac output (Q) and give a typical resting value

Answer 19

The volume of blood ejected from the left ventricle per minute - HR × SV = Q
(Resting Q typically 5l/min)

Question 20

Define bradycardia

Answer 20

A resting heart rate below 60bpm

Question 21

Define breathing rate and give a typical resting and maximal value

Answer 21

The number of inspirations or expirations per minute (resting approximately 12-15 breaths/min, trained = 11-12 breaths/min. Maximal approximately 40-50, trained = 50-60)

Question 22

Define tidal volume and give a typical resting and maximal value

Answer 22

The volume of air inspired or expired per breath (resting approximately 500ml, trained athlete is the same. Maximal approximately 2.5-3L, trained = 3-3.5L)

Question 23

Define minute ventilation and give a typical resting value

Answer 23

The volume of air inspired or expired per minute, TV × f = VE (approximately 6-7.5l/min, trained = 5.5-6)

Question 24

Define association

Answer 24

The combining of oxygen with haemoglobin to form oxyhaemoglobin

Question 25

Define dissociation

Answer 25

The release of oxygen from haemoglobin for gaseous exchange

Question 26

Define the oxyhaemoglobin dissociation curve

Answer 26

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

Question 27

Define Bohr shift

Answer 27

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

Question 28

What is the vasomotor control centre?

Answer 28

The control centre in the medulla oblongata responsible for cardiac output distribution

Question 29

What is vasomotor tone

Answer 29

The partial state of smooth muscle constriction in the arterial walls

Question 30

Define gaseous exchange

Answer 30

The movement of oxygen from the alveoli into the bloodstream and carbon dioxide from the bloodstream into the alveoli via diffusion down a concentration gradient