1.2 Respiratory system

Question 1

Explain the term ‘respiration’

Answer 1

Taking in of oxygen and removal of CO2

Question 2

Identify the pathway air travels when inhaled

Answer 2

Air drawn into the body through the nose, pharynx, larynx, down the trachea, and into left and right bronchus and finally the alveoli.

Question 3

Describe the structure of an alveoli

Answer 3

Alveoli is designed for gaseous exchange, therefore:

• Walls are one cell thick = short diffusion pathway
• Extensive capillary network = good blood flow
• Large surface area = greater uptake of oxygen

BOG = Big sa, One cell thick, Good blood supply

Question 4

Explain what is meant by ‘diffusion’

Answer 4

The movement of gas molecules from an area of high concentration to low concentration.

Question 5

Explain what is meant by the term ‘gaseous exchange’

Answer 5

The movement of oxygen from air into the lungs so it can diffuse into the blood and be transported.
The removal of CO2 from the blood so it can diffuse into the lungs and be expired.

Question 6

Air is a mixture of gases. Air will always move from an area of high to low concentration via diffusion. The greater the concentration gradient the faster air will flow. For inspiration, the pressure needs to be lower in the lungs than in the atmosphere. For expiration, the air pressure needs to be higher in the lungs than the atmosphere.

Answer 6

Air is a mixture of gases. Air will always move from an area of high to low concentration via diffusion. The greater the concentration gradient the faster air will flow. For inspiration, the pressure needs to be lower in the lungs than in the atmosphere. For expiration, the air pressure needs to be higher in the lungs than the atmosphere.

Question 7

At rest, approximately how many litres of air is inspired and expired per breath

Answer 7

0.5 litres

Question 8

Explain the term ‘Tidal volume’

Answer 8

The volume of air inspired or expired per breath

Question 9

Explain what is meant by Inspiratory and Expiratory reserve volume (IRV & ERV)

Answer 9

IRV: volume of air forcibly inspired after normal breath
ERV: volume of air forcibly expired after normal breath

Question 10

Explain the term ‘residual volume’ and identify its importance

Answer 10

Residual volume is the volume of air that remains in the lungs after maximal expiration. We can never totally empty our lungs when we exhale as air is needed to prevent the lung from collapsing.

Question 11

Explain the term ‘minute ventilation’

Answer 11

The volume of air inhaled/exhaled per minute.

Question 12

What is used to measure the volume of air an individual breaths in and out?

Answer 12

Spirometer

Question 13

How could diffusion occur at a faster rate?

Answer 13

The steeper the concentration gradient (difference between concentration gradient at high and low areas) the faster diffusion occurs.

Question 14

What is meant by the term pulmonary ventilation?

Answer 14

Breathing

Question 15

What factors are involved when it comes to regulating pulmonary ventilation during exercise?

Answer 15

Neural control (brain + nervous system)
Chemical control
Hormonal control

Question 16

How do poor lifestyle choices natively impact the respiratory system?

Answer 16

Smoking causes irritation of the trachea and bronchi. Causes breathlessness due to swelling and narrowing of the lungs airway. Mucus builds up due to damaging of cilia resulting in smokers cough. Damage alveoli and reduce efficiency of gaseous exchange.

Question 17

Describe the function of the ‘Cilia’?

Answer 17

Hair like protection to sweep away particles in the lungs

Question 18

Identify what controls breathing and state its location

Answer 18

Respiratory control centre in the Medulla Oblongata

Question 19

Describe the process of inspiration

Answer 19

The intercostal muscles contract, raising the ribs up and outwards, while the diaphragm is forced downwards.

Question 20

Describe the process of expiration

Answer 20

Diaphragm extends upwards and ribs collapse

Question 21

Identify what the body requires to produce energy?

Answer 21

The body requires a continuous supply of oxygen to produce energy. Oxygen is used to break down food to release energy. Carbon dioxide is produced as a waste product which the body needs to remove.

Question 22

Identify how lung volumes change during exercise

Answer 22

Lung volumes during exercise:

Tidal volume + increase
Minute ventilation + increase
IRV - decrease
ERV - decrease
Residual volume = stays the same

Question 23

Briefly explain the pathway taken by oxygen and CO2 during diffusion

Answer 23

Oxygen: alveoli, blood, muscles
CO2: muscles, blood, alveoli

(Reverse order)

Question 24

What percentage of oxygen makes up air?

Answer 24

21% of oxygen makes up air

Question 25

Explain what an alveoli is responsible for

Answer 25

Exchanging gas between the lungs and the blood which occurs via diffusion.

Question 26

Explain what is meant by ‘partial pressure’

Answer 26

The pressure exerted by a gad when it exists within a mixture of gases

Question 27

Explain what is meant by ‘concentration gradient’

Answer 27

Explains how gases flow from an area of high to low concentration. The steeper/bigger the difference, the faster this occurs.

Question 28

Oxygen will diffuse into the ___ from the ___ until the ___ pressure is ___ in both

Answer 28

Oxygen will diffuse into the alveoli from the blood until the partial pressure is equal in both

Question 29

Briefly explain how diffusion occurs at the muscle

Answer 29

The partial pressure of oxygen has to be lower at the muscle than in the blood for diffusion to occur. Oxygen will diffuse from the blood into the muscle until equilibrium is reached.

Question 30

Describe how neural and chemical regulation of pulmonary ventilation occurs

Answer 30

The nervous system controls pulmonary ventilation through two system: the sympathetic and parasympathetic systems. They have opposite effects as they activate different chemicals.

Sympathetic: prepares the body for exercise which increases breathing rate.

Parasympathetic: lowers breathing rate

Question 31

Identify where the respiratory centre is located?

Answer 31

Medulla Oblongata in the brain

Question 32

Identify and explain the areas the respiratory centre consists of

Answer 32

The respiratory centre consists of the inspiratory and expiratory centre.

The inspiratory centre is responsible for inspiration and expiration.

The expiratory centre stimulates the expiratory muscles during exercise.

Question 33

Describe the function of the inspiratory centre

Answer 33

The inspiratory centre sends nerve impulses via the phrenic nerve to the inspiratory muscles (diaphragm and external intercostals) to cause them to contract. This stimulation acts for around 2 seconds and then impulses stop and passive expiration occurs due to elastic recoil of the lungs.

Question 34

Describe the function of the expiratory centre

Answer 34

Send signals and stimulates the expiratory muscles during exercise

Question 35

Describe the process of ‘cellular respiration’

Answer 35

A metabolic reaction that takes place in a cell to obtain energy from fuel (glucose)

Question 36

During exercise, blood ___ increases due to the increase in the___ concentration of CO2 and production of ___.

Answer 36

During exercise, blood acidity increases due to the increase in the ___ concentration of ___ and production of lactic acid.

Question 37

Where are chemoreceptors located?

Answer 37

Carotid artery

Question 38

Describe the function of chemoreceptors

Answer 38

Detect changes in blood chemistry such as an increase in CO2 or lactic acid during exercise. Chemoreceptors send impulses to the inspiratory centre to increase ventilation until blood acidity is back to its normal state.

Question 39

Chemoreceptors send impulses/information to the inspiratory centre to increase pulmonary ventilation during exercise. What takes place for this information to be acted upon?

Answer 39

The respiratory centre sends impulses down the phrenic nerve to stimulate more inspiratory muscles: scalenes, pectoralis minor. As a result, the rate and depth of breathing increases.

Question 40

Identify what causes pressure changes within the lungs

Answer 40

The contraction of muscles cause for pressure changes

Question 41

Identify the muscles being used during the inspiration ventilation phase

Answer 41

Diaphragm, external intercostals, scalenes, pectoralis minor, sternocleidomastoid.

Question 42

Identify the muscles being used during the expiration ventilation phase

Answer 42

Internal intercostals, abdominals

Question 43

The nervous system controls pulmonary ventilation through the use of what systems?

Answer 43

Sympathetic and parasympathetic

Question 44

Describe the function of the respiratory centre

Answer 44

Located in the Medulla oblongata, controls the rate and depth of breathing using both neural and chemical control

Question 45

Describe the role of the proprioceptors in the regulation of pulmonary ventilation

Answer 45

Chemoreceptor - detects chemical changes in the blood (CO2/lactic acid) to increase breathing rate
Baroreceptor - detects changes in blood pressure to increase/decrease breathing rate
Proprioceptor - detects changes in muscle movement/stretch to increase breathing rate

Question 46

Briefly explain the pathway taken by neural/chemical control for inspiration

Answer 46

Receptors > Medulla > Phrenic nerve > diaphragm & external intercostals

Question 47

Identify and explain how hormones regulate pulmonary ventilation during exercise

Answer 47

The hormone Adrenaline acts as a stimulant made in the adrenal gland of the kidney. It is transported in the blood to increase breathing rate. It could be released in anticipation of exercise (just before exercise) to increase oxygen and CO2 exchange.