Gas Exchange Essay, Research Paper
Describe four features of Alveoli that allow them to carry out
gas exchanges efficiently o
small ?
so that the respiratory surface is much larger and much
more gas can be exchanged, o
surrounded by capillaries ?
so that cases are exchanged by diffusion as a
consequence of the different partial pressures of oxygen and carbon dioxide, o
the barrier between the air in an albeolus and the
blood in its capillaries is only about .5 micrometer; o
the alveoli have their own capillaries so that they can
carry away the oxygen and CO2. Explain the necessity of a ventilation system
ventilation lungs- the exchange of air with the
atmosphere takes place by bulk flow as a result of chagnes in lung volume. Draw a diagram of the gas exchange system including trachea,
bronchi, bronchioles and lungs State the difference between breathing and cell respiration
Breathing- inspiration. This is only taking in air into
the body
Respiration is the breakdown of glucose using oxygen.
Also, breathing is carried out by the body; respiration is carried out by
individual cells. Explain how exercise improves the functioning of the heart and
the lungs o
heart ?
stroke volume o
lung ?
tidal volume o
leading to a lowering of both rates Explain how and why breathing rate varies with exercise
Variation in breathing rate o
increase in co2 level o
lowering of pH o
detected by chemosensors (in aorta and carotid
arteries) o
send impulses to breathing centre of brain (brain stem) o
nerve impulses to diaphragm and intercostals muscles to
increase contraction/relaxation rate o
involuntary control, but to some extent controllable
voluntarily Outline a Health problem associated with gas exchange
?The lung is
normally protected by ciliated cells lining the trachea and bronchi. The cilia
sweep out particles in the respired air that are caught in the mucus secreted
by the goblet cells. These cilia are paralysed by chemicals in cigarette smoke.
Cancer cells arising in the bronchi generally do not have cilia. 5.5
Homeostasis Define Homeostasis the maintenance of a constant
internal environment which ensures that an organism?s cells always experience
those conditions which permit effective functioning. Explain the Concept of homeostasis with reference to body
temperature and levels of blood glucose a.
Heat
i.
Monitoring – Thermoreceptors 1. Skin
temperature is monitored by thermoreceptors in the skin 2. Blood
temperature is monitored by thermoreceptors in heat centres in the hypothalamus
ii.
Heat Adjustment mechanisms 1. Warming
down a. Vasodilation b. Sweating 2. Warming
Up a. Vasoconstriction b. Increased
cell metabolism c. Shivering b.
Glucose Adjustment mechanisms
i.
Glucose levels monitored by chemoreceptors in Pancreas 1. Levels
rise due to diet or release from liver and muscles by demand 2. Levels
fall due to respiration or conversion to other metabolites or for storage
(glycogen)
ii.
Adjustment mechanisms 1. Levels
rise a. Pancreas
cells glucagons which stimulates liver cells to convert (enzymically) glycogen
directly to glucose. 2. Levels
high a. Other
pancreas cells secrete insulin that stimulate
i.
Cell respiration
ii.
Increased absorption of glucose by muscle cells
iii.
Increased conversion of glucose 1. to
fat (in adipose tissue) 2. to
glycogen in a. liver
cells b. muscle
cells Explain the concept of Negative Feedback
ie. a house thermostat- when the temperature in your
house drops below the preset thermostat level, the thermostat turns the furnace
on.
When the termperature rises above the preset
temperature the thermostat turns the heat off. A deviation from a ‘preset’
condition stimulates a response that reduces the deviation. State that The nerve (thermoregulation) and endocrine (glucose
regulation) systems are involved in homeostasis. Describe the components of the Nervous System
Central Nervous System
Peripheral Nerves ?
Special cells called neurons ?
Carry electrical impulses rapidly State that the endocrine system consists of glands which release
hormones that are transported in the blood Define Excretion
The removal from an organism of the toxic waste
products of an organism. Define Osmoregulation
The control of the osmotic and water potential in a
cell or inside a living organism State the Functions of the kidney
Osmoregulation
Excretion