Chapter 7: respiration in humans Flashcards
1
Q
Aerobic respiration
A
- the release of energy by the breakdown of glucose in the presence of oxygen. carbon dioxide and water are released as waste products
- releases a large amount of energy
2
Q
Overall equation for aerobic respiration
A
C6H12O6 + 6O2 ➡️ 6CO2 + 6H2O
3
Q
How aerobic respiration is carried out
A
- carried out in a series of steps that are catalysed by enzymes
- mitochondria in cells contain enzyme
- therefore mitochondria plays impt role in respiration
4
Q
What is aerobic respiration used for
A
- complex animals need it since they need large amounts of energy
Ex: - synthesis of new protoplasm for growth and repair
- synthesis of new proteins from amino acids
- active transport in absorption of food substances by small intestine
- muscular contractions
- transmission of nerve impluses
- cell division
5
Q
Anaerobic respiration
A
- release of energy by the breakdown of glucose in absence of oxygen.
- releases a relatively small amount of energy
6
Q
What causes anaerobic respiration
A
- aerobic respiration happens during muscular contractions in muscle cells
- may start panting to remove carbon dioxide and take in oxygen @ faster rate
- heart will beat faster to transport oxygen to muscles faster
- however, there is a limit to increase in rate of breathing and heart rate
- when vigorous activities continue, muscular contractions are so vigorous maximum aerobic respiration is unable to release energy fast enough to meet demand
- as muscular contractions continue, demand increases
- anaerobic respiration takes place to meet the increased demand for energy
7
Q
What happens during anaerobic respiration
A
- lactic acid is formed
- little energy is released
- energy from both types of respiration helps muscles keep contracting
- since there is insufficient oxygen, muscles incurs oxygen dept
- oxygen dept is amount of oxygen required to remove lactic acid
8
Q
How can oxygen dept be removed
A
- continuation of fast heart rate: results in continued and fast transport of lactic acid from muscles to the liver and oxygen from lungs to liver
- Continuation of deeper and faster breathing: results in continued and fast intake of oxygen by lungs. sufficient oxygen is required to remove lactic acid from blood
9
Q
Parts of the respiratory system
A
- external nostril
- nasal passage
- pharynx
- larynx
- trachea
- C-shaped ring of cartilage
- bronchi
- bronchioles
- cluster of alveoli
- diaphragm
- lung
- thorax
- external intercoastal muscle
- internal intercoastal muscle
- rib
10
Q
Nose
A
- air enters via 2 nostrils
- walls of nostrils bears fringe of hairs
- nostrils leads to 2 nasal passages, which are lined with moist mucus membrane
11
Q
Advantages of breathing through nose
A
- dust & foreign particles, including bacteria in the air, are trapped by hairs in the nostrils as well as by mucus on muscus membrane
- as air passes through the nasal passage, it is warmed and moistered
- harmful chemicals may be detected by small sensory cells in mucus membrane
12
Q
From nose to trachea
A
- air in nasal passage enters via pharynx
- from pharynx, air passes into larynx & then into your trachea through an opening
13
Q
Trachea
A
- supported by c-shaped rings of cartilage
- cartilage keeps lumen of the trachea open
- membrane next to lumen is epithelium
- epithelium consists of gland cells and ciliated cells
- gland cells secret mucus to trap dust particles and bacteria
- ciliated cells have hair-like structures called cilia on their surfaces which sweep the dust-trapped mucus up trachea
14
Q
Bronchi & bronchioles
A
- trachea divides into 2 tubes called bronchi (singular:bronchus)
- each bronchus carry air into lung
- similar in structure to trachea
- each bronchus branches repeatedly, giving rise to numerous bronchioles
- bronchioles are very fine tubes
- each bronchioles end with cluster of alveoli
15
Q
Alveoli
A
- gas exchange takes place through walls of alveoli
- numerous alveoli are found in lungs, providing a very large surface area for gas exchange
16
Q
How are lungs adapted for efficient gas exchange
A
- numerous alveoli in lungs, providing larger surface area for gas exchange, hence quicker rate of absorption of oxygen
- wall of alveolus is 1 cell thick. Short diffusion distance ensures higher rate of diffusion of gases
- thin film of moisture covering inner wall of alveolus allows oxygen to dissolve in it & diffuse into the blood capillaries surrounding the alveolus quickly
- walls of alveoli are richly supplied with blood capillaries with continuous blood flow to maintain steep concentration gradient
17
Q
Gas exchange
A
- exchange of gas between an organism and its environment
18
Q
How does gas exchange happen in alveoli
A
- by diffusion
- blood entering lungs has lower concentration of oxygen & higher concentration of carbon dioxide
- concentration gradient of oxygen and carbon dioxide is set up between blood and air
- oxygen dissolve into thin film of moisture and then diffuse through wall of alveolus and capillary into red blood cells
- carbon dioxide diffuses from blood into air
- concentration gradient is maintained by continuous flow of blood in capillaries & continuous breathing, causing air in lungs to be constantly refreshed
19
Q
How is oxygen transported in body
A
- in lungs, where oxygen concentration is high, oxygen combine with haemoglobin in red blood cells to form oxyhaemoglobin
- oxygenated blood is then transported from lungs to other parts of body
- when blood passes through an organ/tissue where oxygen concentration is low, oxyhemoglobin will release its oxygen to respiring cells
20
Q
The Thoracic cavity
A
- chest wall is surrounded by ribs
- between ribs is the internal intercoastal muscle and the external intercoastal muscles
- they are antagonistic muscles
- thorax is separated from the abdomen by diaphragm
- diaphragm is made out of muscles and elastic tissue
- when diaphragm muscles contract, diaphragm flattens
- when diaphragm muscles, diaphragm arches upwards
- intercoastal muscles and diaphragm work together to change volume of the thoracic cavity
21
Q
Inspiration (inhalation)
A
- diaphragm muscles contract, diaphragm flattens
- internal intercoastal muscles relax, external intercoastal muscles contract (RICE)
- ribs move upwards and outwards.
- sternum moves up and forwards
- volume of thoracic cavity increases
- atmospheric pressure is higher than pressure in lungs
- aire moves into lungs
22
Q
Expiration (Exhalation)
A
- diaphragm relaxes and arches upwards
- external intercoastal muscles relax, which internal intercoastal muscles contract (ERIC)
- ribs move downwards and inwards
- sternum moves down and it original position
- volume of thoracic cavity decreases
- lungs are compressed & air pressure inside them increases as volume decreases
- pressure in lungs is higher than atmospheric pressure
- air is forced out of lungs into exterior envrionment
23
Q
Diff between inspired and expired air
A
- more oxygen in inspired air
- more carbon dioxide in expired air
- same amount of nitrogen
- water vapour is saturated in expired air, but is rarely saturated in inspired air
- more dust particles in inspired air
- temperature of expired air is always body temp, but can vary for inspired air
24
Q
Chemicals in tobacco smoke
A
- nicotine
- carbon monoxide
- Tar
25
Q
Effects of nicotine
A
- increases heart rate and blood pressure
- increase risk of blood clots in arteries, increasing risk of coronary heart disease
- increases risk of arteries narrowing
- narrow arteries decrease amount of food substances reaching fetus, affecting fetus development
26
Q
Effects of carbon monoxide
A
- reduces ability of blood to transport oxygen as carbon monoxide binds permanently with haemoglobin
- there will be less haemoglobin available to transport oxygen
- can affect fetal development, since less oxygen reaches fetus
- increase risk of coronary heart disease
27
Q
Effects of tar
A
- increases risk of cancer in lungs as it can cause uncontrolled cell division
- increases risks of chronic bronchitis and emphysema
- tar paralyses the cillia lining the air passages
- dust particles trapped in mucus lining cannot be removed
28
Q
Diseases cause by tobacco smoke
A
- Chronic bronchitis
- Emphysema
- Lung cancer
29
Q
Chronic bronchitis
A
- epithelium lining of air passages becomes inflamed
- excessive mucus is secreted by epithelium
- cilia on the epithelium are paralysed
- mucus & dust particles cannot be removed
- air passages becomes blocked, making breathing difficult
- in order to breathe, persistent coughing occurs to clear the air passages, increasing risk of lung infection
30
Q
Emphysema
A
- partition walls between alveoli break down due to persistent and violent coughing
- results a decreased surface area for gaseous exchange
- lungs lose their elasticity and become inflated with air
- breathing becomes difficult
- wheezing & severe breathlessness results
- when a person has chronic bronchitis & emphysema, they have chronic obstructive lung disease
31
Q
Lung cancer
A
- risk of lung cancer increases when a person smokes tobacco
- smoking also increases risk of cancers of mouth, throat, pancreas, kidneys and urinary bladder
