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life sciences gr 11 > gaseous exchange > Flashcards

gaseous exchange Flashcards

1
Q

Distinguish between breathing, gaseous exchange and cellurar respiration

A

breathing is the mechanical process whereby air moves in and out of the lung
gaseous exchange is a physical process which involves the exchange of gases between the air and the blood in the lungs
cellular respiration is a chemical process which takes place within the cells in order to release energy

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2
Q

Requirements for for an effective gaseous exchange system

A

the gaseous exchange surface must :

  • be large to maximize the gaseous exchange
  • be thin for quick and easy diffusion
  • be moist because oxygen and carbon dioxide must be in solution to diffuse through a membrane
  • be having a transport system for efficient transport of gases
  • be well protected because it is very thin and fragile
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3
Q

the movement of molecules from a high concentration to a low concentration until equilibrium is reached

A

diffusion

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4
Q

the air passage,lungs and respiratory muscles are part of this system

A

he human respiratory sysyem

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5
Q

the air passage

A

it transports air to and from the lungs ,

it consists of the nasal cavity, pharynx,trachea,bronchi an bronchioli and alveoli

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6
Q

the nasal cavity

A 
it has 2 external nostrils that lead to the two nasal cavities.
# small hairs in the nasal cavity filter large particles from the inhaled air.
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7
Q

how is the nasal cavity adapted to suit its function

A

it is lined with a mucous membrane that is line up with cilliated columnar epithelial cells
+ the columnar epithelial cells are richly supplied with superficial blood capillaries the warm the incoming air
+ goblet cells in the columnar epithelial secret mucus
+ the mucus -traps ducts and germ particle
-it is also antiseptic and prevents inhaled
germs from multiplying
-moistens the incoming air
+ the cilia on the columnar epithelial continuously performs sweeping movements in the direction away from the lungs

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8
Q

the pharynx

A
  • connects the nasal cavity with the larynx
  • it is lined with a mucus membrane
  • it leads to 2 openinngs: the glottis that leads to the trachea and the oesophagus
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9
Q

how is the pharynx’s membrane adapted to suits its functions

A

it is lined with a mucous membrane that is line up with cilliated columnar epithelial cells
+ the columnar epithelial cells are richly supplied with superficial blood capillaries the warm the incoming air
+ goblet cells in the columnar epithelial secret mucus
+ the mucus -traps ducts and germ particle
-it is also antiseptic and prevents inhaled
germs from multiplying
-moistens the incoming air
+ the cilia on the columnar epithelial continuously performs sweeping movements in the direction away from the lungs

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10
Q

trachea

A

^it is a long , tubular structure the is located in-front of the oesophagus
^ The larynx is located at the top of the trachea
^ the epiglottis is a leaf-shaped cartilage structure that closes when food is swallowed, preventing food from entering the trachea and choking
^ C-shaped cartilage ring protects the trachea and keeps it open for easy movement of air
^it is also lined with cilliated columnar epithelial cells

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11
Q

bronchi and bronchioli

A

& the trachea divides into the left and right bronchus that enters the lungs respectively
$ the bronchi are lined with a mucous membrane and held open by o-shaped cartilage rings
inside the lung, the bronchi branches into bronchioles and loses their cartilage
$ each bronchioli ends in an infundibulum which consists of groups of alveoli

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12
Q

alveoli

A
  • they are site for gaseous exchange
  • the many alveolis increase the surface area to maximize gaseous exchange
  • they have this walls of squamous epithelial cells allowing for easy diffusion of gases
  • tissue fluids keep the walls of the alveolis moist
  • a large blood capillary network surrounds the alveolis
  • the walls of the capillaries consits of a single layer endothelium
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13
Q

lungs

A
  • lungs are spongy and elastic
  • they are surrounded and protected by 12 pairs of ribs
  • intercostal muscles are found between the ribs
  • the right ling has 3 lobes
  • the left lung has 2 lobes
  • surrounded by a double pleura membrane
  • intrapleural fluid between the 2 pleura membranes acts as a lubricant and helps prevent friction during inhalation and exhalation
  • the lungs are conical and rest the bottom on a dome-shaped muscle plate called the diaphragm
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14
Q

adaptions of the lungs for their functions

A
  • lungs are spongy and elastic- can expand and contrast easily during breathing
  • lungs are surrounded by a double pleura membrane, with intrapleural fluid between the 2 membrane - prevents friction during breathing
  • Bronchioli eventually ends in millions of alveoli- increases the gaseous exchange sites
  • the wall of the alveolus consists of a single layer of squamous epithelium- thin surface for efficient gaseous exchange
  • alveoli are surrounded by a network of blood capillaries-transports of oxygen to the tissue and carbon dioxide to the lungs
  • walls of blood capillaries consist of a single layer of endothelium - thin surface for efficient gaseous exchange
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15
Q

respiratory muscles

A

Diaphragm- it is a dome shaped muscle plate that separates the chest and abdomen to form a airtight thoracic cavity

Intercostal muscles- the are located between consecutive rib and consists of two sets

  • external intercostal muscles
  • internal intercostal muscles
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16
Q

red blood cells

A

erythrocytes

17
Q

hemoglobin

A

oxygen carrying protein pigment in the blood

18
Q

iron

A

the element found in the hemoglobin molecule to which oxygen atom bonds

19
Q

what happens during inhalation

A
  • The diaphragm contrast and the thoracic cavity enlarges from top to bottom
  • the external intercostal muscles contrast causing the ribs to move upwards and outwards
  • the thoracic cavity enlarges from side to side and front to back
  • the abdominal muscles relax so that the abdominal cavity can accommodate the viscera being pushed down by the diaphragm
  • the total volume of the thoracic cavity is increased and the pressure in the thoracic cavity and lungs decreases
  • the elastic lung expands
  • since the atmospheric pressure is higher than the pressure in the thoracic cavity and the lungs, oxygen rich air flows into the lungs
20
Q

explain why inhalation is considered an active process

A

inhalation is associated with contraction of the diaphragm and external intercostal muscles, which increases the volume of the thoracic cavity

21
Q

what happens during exhalation

A
  • the diaphragm relaxes and returns to original position while the thoracic cavity becomes smaller from top to bottom
  • the external intracostal muscles relaxes causing the ribs to move down and inward
  • the thoracic cavity reduces in size and the total volume of the thoracic cavity is reduced while the pressure increases in the thoracic cavity and the lungs
  • since the pressure in the chest cavity and the lungs is higher than the atmospheric pressure, carbon dioxide rich air flows out of the lungs
22
Q

explain why exhalation is considered as a passive process

A

exhalation is associated with the with the relaxation of the diaphragm and the external intercostal muscles, which decreases in the volume of the thoracic cavity

23
Q

gaseous exchange in the alveoli in detail ( external gaseous exchange)

A
  1. the air entering the the alveoli from inhalation has a high oxygen concentration compared to the oxygen concentration in the blood of the surrounding capillaries
  2. this results in oxygen diffusion from the alveoli into the blood and carbon dioxide from the blood and back into the alveoli. THEREFORE gases are exchanged due to concentration gradient
  3. Deoxygenated blood comes from the heart and past the alveoli has a low oxygen concentration
  4. Oxygenated blood leaves the alveoli with a high concentration of oxygen
  5. The blood will take the oxygen to the cells where it is need
  6. the air in the alveoli will be exhaled with more carbon dioxide than the air that is inhaled
24
Q

explain the the transport of respiratory gases occur

A

Oxygen is transported by erythrocytes since most oxygen combines with haemoglobin present in the erythrocytes to form OXYHAEMOGLOBIN. it is transported via the circulatory system to all body cells

most of the carbon dioxide is transported in the blood plasma as BICARBONATE IONS and also combines with haemoglobin to form CARBOMINOHAEMOGLOBIN

25
Q

gaseous exchange in the tissue ( internal gaseous exchange in detail

A
  1. oxygen combines with haemoglobin present in the erythrocytes to form oxyhaemoglobin
  2. it is transported via the circulatory system to all body cells
  3. Due to concentration difference between the cells and the tissues, oxygen diffuses through the endothelial walls of the capillaries into the tissue fluid that surrounds the cells and into the cells
  4. the cells have a high carbon dioxide concentration due to continuous cellular respiration
  5. this carbon dioxide moves out of the cells into the blood and is transported back to the heart and then to the lungs where it is exhaled.
  6. the cells are bathed in tissue fluid which supplies the necessary moisture for gases exchange
26
Q

what controls the breathing rate and how does it operate

A

the respiratory centre in the medulla oblongata of the human brain controls the breathing rate

The respiratory centre sends nerve impulses to the respiratory muscles to accelerate or decelerate contraction and relaxation

27
Q

what controls the heart rate and explain how it operates it operate

A

the cardiovascular centre located in the medulla oblongata controls the heart rate

The cardiovascular centre send nerve impulses to the heart muscle to accelerate or decelerate contraction r relaxation

28
Q

what is the function of negative feedback mechanisms

A

it stabilizes a system and returns it to its normal state

29
Q

what are feedback loops

A

they are systems which are initiated when an internal alarm is set off and where the body responses

30
Q

the ability of the body to return the levels to normal

A

homeostasis

31
Q

explain how homeostatic control of breathing works

A
  1. carbon dioxide levels in the body increases above normal levels
  2. the chemo-receptors in the aorta and at the base of the jugular arteries are stimulated
  3. they send nerve impulses to the respiratory and cardiovascular centres in the medulla oblongata of the brain
  4. the respiratory centres in turn sends nerve impulses to the respiratory muscles to accelerate contraction and relaxation
  5. the rate of breathing thus increases and more carbon dioxide laden air is exhaled
  6. the cardiovascular centres sends nerve impulses to the heart muscle and arterioles
  7. the heart rate increases , the arterioles constrict and blood flows faster
  8. carbon dioxide is transported to the lungs faster, where it is exhaled
  9. the carbon dioxide concentration in the blood thus returns to normal
32
Q

what is the effect of altitude on gaseous exchange and how athletes have ton= do si that this wont affect their chances in the copetition

A
  • with an increase in altitude , atmospheric pressure drops and so does the amount of oxygen in the atmosphere
  • People living at a high altitude usually have more red blood cells to transport a maximum amount of oxygen efficiently
  • if a person living at sea level goes to an area high above sea level for a while his/her body adapts after a few days or even weeks and produces more red blood cells
  • in this way , the oxygen carrying capacity of the blood is increased
  • it is especially important for athletes living at sea level who plan to participate in a competition at a higher altitude , to arrive at the higher altitude in advance. this gives the body enough time to adjust.
  • it the athlete’s body does not have enough time to adjust, he/she will tire very quickly
  • his/her red blood cells has too few red blood cells to carry enough oxygen to the muscle tissues for respiration and consequent energy release

life sciences gr 11 (10 decks)

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