Mammalian systems Chapter 3 Pages 75-103
Learning intentions To know that multicellular organisms exist from specialized cells To know how the respiratory system is specialized and organized and how a specific malfunction can lead to biological consequences To understand how the system is interconnected to other systems for the survival of an organism. Success criteria I can explain how the specialized cells of the respiratory system function and the importance of gas exchange I can identify the issues if the organs in the system malfunction and lead to diseases such as emphysema, lung cancer, asthma and lung infections
Levels of organisation Multicellular organisms have complex levels of organisation This allows cells to specialise in form and function to perform various functions for the whole organism. In animals this might relate to: Movement Food capture Reproduction Defence In plants this might relate to: Capture of sunlight Cell division Transport of nutrients Cells Tissues Organs Systems
Organisation at the cellular level e.g. sponges no tissues, no organs, no circulatory, nervous or digestive systems Organisation at the tissue level e.g. jellyfish, anemones and coral tissue cells present (cells of a similar type work together to carry out a specific function) = stinging cells for defence in jelly fish. No organs or systems. Organisation at the organ level e.g. flatworms (parasites like tapeworm). No circulatory or respiratory systems. Do have excretory organs, stomach and eyespots Organisation at the system level e.g. earthworms (first to show this level of organisation). These contain circulatory, nervous and digestive system.
Mammalian tissues, organs and systems The major tissues in humans (as with many animals) are: Epithelial tissue Muscle tissue Connective tissue Nervous tissue
Systems do not operate in isolation Systems are interconnected and rely on the operation of all other systems. System respiratory system Some organs of system lungs Examples of interactions with the nervous system brain monitors blood gas levels and breathing rate lungs are source of oxygen for brain Can you think of some examples? skeletal system circulatory system bones heart, blood vessels brain controls muscles and so regulates position of skeleton skull and spine protect brain and spinal cord brain regulates blood pressure and heart rate cardiovascular system delivers nutrients and oxygen to cells of nerve tissue excretory (urinary) system kidneys, bladder brain controls urination bladder sends sensory information to the brain digestive system mouth to anus brain controls muscles for eating and for elimination digestive system sends sensory information to the brain
The Respiratory System http://www.youtube.com/watch?v=mrdbikqotlu (also on the class website)
Gaseous Exchange in Fish (extra info.) Oxygen dissolved in water is only 3-5% of what is available in the air Fish are able to live in such an environment (underwater) due to partial buoyancy Fish require less energy for balance, therefore less oxygen is required, compared to a land animal No energy is expended keeping respiratory organs (gills) moist Gills On each side of the fish there is a flap called an operculum, under which is a series of four gill arches Each arch extends into two filaments made of many lamellae (series of flat plates acting as gas exchange surfaces)
Gaseous Exchange in Fish The direction of blood flow is opposite to the direction of water flow over the gills (counter current), creating a concentration gradient extended along the lamella If blood flow and water flow were in the same direction, an equilibrium would be reached Oxygen diffuses over a very short distance to the red blood cells travelling almost single file through the lamellae Fish opens mouth, water accumulates and mouth closes The base of the mouth is raised exerting force on the water The opercula open, water flows over the gills and exits the fish
Gaseous Exchange in Insects (extra info) Insects have a series of air filled tubes that provide oxygen to living cells, called trachea Air enters this tracheal system via special inlets called spiracles Spiracles vary in structure, often have muscular flaps that open and close or can be covered by cuticular meshwork preventing foreign objects entering The opening is extension of cuticular lining made of chitin and protein The air moves in the trachea, then into smaller branches called tracheoles, which are in close contact with cells Due to insect size, diffusion is sufficient to supply cells Active flying insects have greater oxygen needs and achieve this by having air sacs that expand and contract with every wing beat Carbon dioxide diffuses out of cells into the tracheoles