exchange and transport systems (humans)

Question 1

why is breathing important in humans?

Answer 1

need to get oxygen into the blood for respiration, and carbon dioxide out as a waste product of respiration

Question 2

what is the human gas exchange system composed of?

Answer 2

lungs 
trachea 
bronchi 
bronchioles 
alveoli

Question 3

what are the stages of inspiration?

Answer 3

external intercostal and diaphragm muscles contract
ribcage moves up and out, which causes the diaphragm to flatten
this increases the volume of the thoracic cavity
lung pressure decreases
air flows down a pressure gradient down a trachea into the lungs

Question 4

what are the stages of expiration?

Answer 4

external intercostals and diaphragm muscles relax
ribcage moves down and in, diaphragm curves
volume of the thoracic cavity decreases, which causes air pressure to increase
air is forced down a pressure gradient and out of the lungs

Question 5

what are the adaptations of the alveoli?

Answer 5

epithelium one cell thick
large surface area to volume ratio
permeable 
rich blood supply 
elastic tissue 
sufracant reduces surface tension

Question 6

how does oxygen leave the alveoli?

Answer 6

oxygen diffuses from the alveoli down a concentration gradient
across the alveolar epithelium
across the capillary endothelium
into the blood

Question 7

how does carbon dioxide enter the alveoli?

Answer 7

carbon dioxide diffuses from the capillary 
down a concentration gradient 
across the capillary endothelium 
across the alveolar epithelium 
into the alveoli

Question 8

what is tidal volume?

Answer 8

volume of air entering and leaving the lungs in a resting breath

Question 9

what is vital capacity?

Answer 9

maximum volume of air we can inhale and exhale

Question 10

what is residual volume?

Answer 10

volume of air left in the lungs after the strongest exhalation

Question 11

what is the equation for total lung capacity?

Answer 11

vital capacity+residual volume

Question 12

what is pulmonary ventillation?

Answer 12

volume of air moving in and out of the lungs per minute

Question 13

what is the equation for pulmonary ventillation?

Answer 13

tidal volume x respiration rate

Question 14

what happens in pulmonary tuberculosis?

Answer 14

immune system builds a wall around bacteria in the lungs
forms small, hard lumps known as tubercles
infected tissues within the tubercles dies and gas exchange surface is damaged
causes fibrosis which further reduces tidal volume
ventilation rate increased

Question 15

what are the symptoms of fibrosis?

Answer 15

persistent cough 
cough up blood and mucus
chest pains 
shortness of breath 
fatigue

Question 16

what happens in fibrosis?

Answer 16

formation of scar tissue in the lungs
could be due to an infection or exposure to substances like asbestos/dust
scar tissue thicker and less elastic-so less able to expand
tidal volume and forced vital capacity reduced
reduction of gas exchange-diffusion slower across a scarred membrane

Question 17

what are the symptoms of fibrosis?

Answer 17

shortness of breath, dry cough, chest pain, fatigue, weakness

Question 18

what is asthma?

Answer 18

respiratory condition where the airways become inflamed and irritated
usually due to an allergic reaction from substances like pollen and dust
during an asthma attack- smooth muscle lining the bronchioles contracts and a large amount of mucus is produced
constriction of airways-difficult to breathe properly
air flow reduced so forced expiratory volume reduced

Question 19

what are the symptoms of asthma?

Answer 19

wheezing
tight chest
shortness of breath

Question 20

what is emphysema?

Answer 20

lung disease caused by smoking/long term exposure to air pollution
particles become trapped in the alveoli, which causes inflammation
this attracts phagocytes to the area, which produce an enzyme which breaks down elastin
alveoli cannot recoil to expel air- trapped in alveoli
destroys alveoli walls- reduces the surface area of the alveoli

Question 21

what are the symptoms of emphysema?

Answer 21

shortness of breath

wheezing