Chapter 07 - Respiration in Humans Flashcards
What is respiration?
A process by which energy is produced from oxidation of food
What are the 2 types of respiration?
1) Aerobic
2) Anaerobic
What is aerobic respiration?
Aerobic respiration is the release of energy by the break down of glucose in the presence of oxygen
What is it known as when food molecules are combined with oxygen?
The food is said to be oxidised
What is released during aerobic respiration?
Carbon dioxide and water as waste products and a lot of energy
What atoms do all food molecules contain and what does oxidation do?
All food molecules contain carbon, hydrogen and oxygen atoms. Oxidation converts carbon atoms into carbon dioxide and hydrogen into water
What is the chemical equation for aerobic respiration?
C6H12O6 + 6O2 –> 6CO2 + 6H2O
What is the word equation for aerobic respiration?
glucose + oxygen –> carbon dioxide + water
Respiration is catalysed by enzymes found in ____
Mitochondria, hence it plays an important role in aerobic respiration
Energy is needed by many vital processes and activities. Name 2
1) Synthesis of new protoplasm for growth and repair
2) Synthesis of proteins from amino acids
3) Active transport of food substances in the small intestine
4) Muscular contraction
5) Transmission of nerve impulses
6) Cell division
Extra: In animals some energy is released as heat to maintain body temperature
What is anaerobic respiration?
The release of energy by the breakdown of glucose in the absence of oxygen
What is released from anaerobic respiration?
A small amount of energy
How is lactic acid formed?
1) During vigorous muscular contractions, muscles will respire aerobically at a high rate
2) Panting occurs to remove carbon dioxide and take in oxygen faster
3) Heart beats faster, oxygen transported to muscles faster, however there is a limit to the breathing rate
4) Muscular contraction are so vigorous that max aerobic respiration is not enough to meet the demand
5) Muscles then carry out anaerobic respiration and lactic acid is formed
What causes the fatigue in muscles and aching pain?
The build up of lactic acid
What happens to the lactic acid in the liver?
It will be oxidised to carbon dioxide and water in the liver, using up oxygen in the process and producing energy at the same time
What does the accumulation of lactic acid create?
An oxygen debt
What are the 2 ways to remove lactic acid?
1) Continuation of fast heart rate resulting
- fast transport of lactic acid from the muscles to the liver
- fast transport of O2 from lungs to liver
2) Continuation of deeper/faster breathing resulting in fast intake of O2 by lungs
What is gas exchange?
Gas exchange is the exchange of gases between organism and an environment
Which gases exchange take place simultaneously and why?
Oxygen and carbon dioxide. Humans require a constant supply of oxygen for tissue respiration. At the same time, they must remove excess carbon dioxide takes places continously between the human body and atmosphere
Describe the structures from the nose to the trachea
1) Air enters our body through the external nostrils mainly
2) Advantages of breathing through the nose
- Hairs on the wall of the nostrils and the mucus on the mucous membrane of the nasal passages trap dust and foreign particles
- Air is warmed and moistened
- Small, sensory cells in the mucous membrane detect harmful chemicals
3) From the nose, air flows through the nasal passage, passing through the pharynx, larynx, trachea
Describe the structures in the trachea
1) It is the passage from the back of the mouth to the lungs
2) The presence of incomplete C-rings of cartilage prevents the trachea and bronchi from collapsing when we breathe in
3) Epithelium that lines the inside of the trachea, bronchi and bronchioles consist of gland cells and ciliated cells
- Gland cells secrete mucus to trap dust particles and bacteria
- Ciliated cells hair-like structures called cilia the surface to sweep the dust-trapped mucus up the trachea
Describe the structures from the bronchi to bronchioles
Bronchi are 2 small tubes that branch out from the trachea and enter the lungs. They further divide into even smaller branches called bronchioles
Describe the structure of alveoli
1) Each bronchioles ends in a cluster of air sacs called alveoli
2) Alveoli have characteristics to facilitate gas exchange more efficiently
- One cell thick epithelium for faster diffusion of gases
- Dense blood capillary network that can quickly bring oxygen away to the cells and maintains the diffusion gradient
- Thin layer of moisture on the surface that allows gases to dissolve into the lining of the alveoli
- Large number of alveoli that provides a large surface exchange of gases
What gas exchange takes place in the lungs?
Gas exchange is the exchange of oxygen and carbon dioxide between air and the lungs. This exchange takes place across the surface of the alveoli and blood capillaries in the lungs
How is gas exchange rake place in the lungs?
There is a concentration gradient for each gas between the spaces in the alveoli and blood, so gas exchange is carried out by diffusion
- Oxygen diffuses from alveolar air into the blood
- Carbon dioxide diffuses form the blood into the alveolar air
How are concentration gradients of oxygen and carbon dioxide between the alveolar air and blood is maintained?
1) Continuous flow of blood through the blood capillaries
2) Continuous breathing, which refresh the air in the lungs constantly
Describe the process of oxygen diffusing from the alveolar air to the blood
1) Inhaled air in the alveolus contains higher concentration of oxygen than in the blood capillaries surrounding the alveolus
2) This causes the oxygen to dissolve in the layer of moisture on the surface of the alveolus
3) It then diffuses through the wall of alveolus and the wall of the blood capillary into the red blood cells
4) Oxygen combines with haemoglobin in the red blood cells to form oxyhaemoglobin
5) The blood capillaries that carry oxygenated blood from the alveoli join to form pulmonary vein, which returns blood to the left atrium of the heart
Describe the process of blood transported from the blood capillaries to the heart
6) Blood enters the left ventricle and is pumped all around the body, supplying the tissues which have lower concentration of oxygen
7) Oxyhaemoglobin is not stable. It dissociates easily to release oxygen in the surroundings that are low in oxygen concentration
What is the thoraic cavity?
The hollow space inside the human body (aka chest cavity), protected by the chest wall
What supports the chest wall?
The ribs
What are between the ribs?
There are two sets of antagonistic muscles, the external and internal intercostal muscles
What are antagonistic muscles?
When one relaxes, the other contracts
What for the ribs form with the sternum?
The ribs form the rib cage with the sternum at the front
What is the dome-shaped sheet called that separates the thoracic cavity from the abdomen?
Diaphragm, made up of muscle and elastic tissue.
- When the diaphragm muscles contract, the diaphragm flattens downwards
- When the diaphragm muscles relax, the diaphragm arches upwards
How is the breathing mechanism in humans brought about?
By the collective actions of intercostal muscles and diaphragm muscles
What are the 2 phases in the breathing movement?
1) Inspiration: Taking in of air
2) Expiration: Giving out of air
Describe inhalation
1) Diaphragm muscles contract, the diaphragm flattens downwards
2) External intercostal muscles contract
3) Internal intercostal muscles relax
4) Ribs and sternum move up and forward
5) Lungs expand, volume of thoracic cavity increases, causing air pressure in the lungs to decrease
6) Atmospheric pressure is higher than the pressure within the lungs, forcing the atmospheric air into the lungs
Describe exhalation
1) Diaphragm muscles relax, the diaphragm arches upward
2) External intercostal muscles relax
3) Internal intercostal muscles contract
4) Ribs and sternum move down to its original position
5) And the lungs are compressed, volume of thoracic cavity decreases, causing air pressure in the lungs to increase
6) Pressure in lungs is higher than atmospheric pressure, forcing alveolar air out of lungs
