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Gas Exchange/Respiratory System

Terms in this set (77)

Gas Exchange
the physical methods that organisms have for obtaining oxygen from their surroundings and removing excess carbon dioxide
gas exchange is interchangeable with
respiration
respiration is interchangeable with
gas exchange
respiratory surface
a surface through which gas exchange takes place
What are the characteristics of a respiratory surface?
~must be thin-walled, so diffusion can occur across it rapidly
~must be moist because oxygen and carbon dioxide must be in solution
~must be in contact with a source of oxygen that exists in the surroundings
~in most multicellular animals, it must be in contact with the transport system that carries dissolved materials to and from the cells of the organism
gas exchange occurs across the respiratory surface by
diffusion
concentration gradient
controls the flow of gases
the larger the area of the respiratory surface,
the more gas exchanges car occur at a given time
gas exchange: protists and small multicellular animals
ex.
directly between the body (somatic) cells and the environment (across body surface)
ex: ameba and paramecium
gas exchange: large multicellular animals
respiratory surfaces in specialized organs and organ systems
Why does gas exchange not directly occur between cells and environment in large multicellular animals?
~the cells are not close to the outside environment
~the skin is often dry, scaled or feathered preventing gas exchange through the skin
explain gas exchange in protists (specifically ameba and paramecium)
obtain dissolved oxygen in water, so they are constantly moving large volumes of water over their respiratory surface. oxygen diffuses across cell membrane into cytoplasm while carbon dioxide diffuses from cytoplasm across the cell membrane into the surrounding water
Oxygen percent in water? air?
less than 1% in water
21% of air
explain what oxygen molecules can be obtained from water by aquatic animals
only the free oxygen molecules dissolved in water can be obtained
oxygen that is chemically apart of water molecules cannot be obtained through gas exchange
why must respiratory surfaces be moist?
oxygen and carbon dioxide must be in solution during gas exchange
why do most multicellular organisms have respiratory surfaces that extend within the animal?
to protect the respiratory surface, lower the amount of water lost by evaporation, and keep the respiratory surface close to the transport system that will transport the gases throughout the organism
where are respiratory pigments mainly found?
in many multicellular organisms
how does gas exchange occur in hydra
can take place by direct diffusion between body cells and the environment
how many cell layers do hydra have?
2 layers (ectoderm and endoderm)
what are respiratory pigments?
substances that carry oxygen and carbon dioxide between the respiratory surface and the body cells
allow the blood to carry more oxygen and carbon dioxide than plain water can
Out of 100 milliliters: oxygen and carbon dioxide carried by water
0.2 milliliters of oxygen and 0.3 milliliters of carbon dioxide
Out of 100 milliliters: oxygen and carbon dioxide carried by hemoglobin
20 milliliters of oxygen and 30-60 milliliters of carbon dioxide
what is the respiratory surface in earthworms? what qualifies it as a respiratory surface?
skin is the respiratory surface
~the earthworm's skin is moist, so oxygen and carbon dioxide will be in solution
~the earthworm's skin is thin-walled, so diffusion can occur across it rapidly
~it is, for the most part, near a source of oxygen existing in the surroundings
~it is in contact with a transport system (capillaries(hemoglobin)) that carries dissolved substances (oxygen/carbon dioxide) to and from the cells of an organism
describe the skin of earthworms
the skin is moist, due to mucus secreted by specialized cells
large number of capillaries under the skin
describe the diffusion of oxygen and carbon dioxide (earthworm)
oxygen from air in the soil diffuses through their skin into the capillaries
carbon dioxide diffuses from the blood in the capillaries through the skin into the air
what happens to oxygen once it enters the blood? carbon dioxide?
hemoglobin picks it up and takes it to different parts of the body, once oxygen is dropped off carbon dioxide is picked up and brought near the skin where it diffuses through the skin out of the earthworm
if the soil is too dry (earthworm)
the earthworm will suffocate due to lack of moisture on its respiratory surface because in order for gas exchange to occur, oxygen and carbon dioxide must be in solution
if the soil is too wet/it's raining (earthworm)
the earthworm will move to a new burrow to avoid drowning since there is too little dissolved oxygen
where does gas exchange not occur in grasshoppers?
the circulatory system and oxygen/carbon dioxide is not carried by the blood
tracheal tubes
system of air tubes that carries air directly to all the cells of the body
what are spiracles, how many?
spiracles are openings that allow air to enter and leave the grasshopper's body (10 pairs exist: 4 front pairs, and 6 rear pairs)
from each spiracle tracheal tubes branch....... (size)
smaller and smaller
what is the respiratory surface in grasshoppers
the fluid filled end of the tracheal tube
the tracheal tube is in direct contact with
the body cells
diffusion between body cell and tracheal tube: oxygen and carbon dioxide
oxygen diffuses from tracheal tube to body cell
carbon dioxide diffuses from the body cell to the tracheal tube
how is air pumped into and out of the tracheal system
by contraction of the grasshoppers muscles and air sacs help to pump air into and out of the tracheal system
when the area around the tracheal tube expands
air flows in through the front four pairs of spiracles
when the area around the tracheal tube contracts
the front four pairs of spiracles closes and air flows out the six rear pairs of spiracles
what are air sacs
several large, collapsible, balloonlike chambers that help to pump air in and out of the tracheal system, which (air sacs) are connected to the tracheal tubes
what are gills?
thin layers of tissue that are richly filled with blood vessels
the respiratory surface in aquatic animals (e.g. fish, clams, oysters, lobsters)
how do gills work(oxygen and carbon dioxide)?
as water passes over gills, the dissolved oxygen diffuses through the gill tissue into the blood of the underlying blood vessels and is then transported to different parts of the animal's body. carbon dioxide from the blood diffuses out of the gill tissues and into the water.
why must there be a constant flow of water over the gills?
the gills can stick together if they are dry preventing gas exchange
there are small amounts of oxygen that are able to be obtained by animals through gas exchange, so water needs to constantly be moved over the gills
animal can die from too little oxygen
the human respiratory system is made up of
the lungs and a system of air tubes that carry air to and from the lungs
lungs
~gas exchange organ in air-breathing vertebrates and other animals
~made up of small chambers, each chamber having a huge respiratory surface for the diffusion of oxygen into the blood and the diffusion of carbon dioxide out of the blood
~fills up a large part of the chest cavity
diaphragm
the muscle that forms the floor of the chest cavity and separates the lungs from the abdominal cavity
pleura
~two layered membrane that completely encloses each lung
~one layer of the pleura covers each lung
~the other layer is in contact with the diaphragm and the other organs in the chest
~a lubricating fluid between the two layers allows the lungs to move freely in the chest during breathing
path of air to the lungs
nose/nostrils/nasal passages, pharynx, larynx, trachea, bronchi, bronchial tubes, bronchioles, alveoli
air normally enters through the
nostrils
hollow spaces in the nose
nasal cavity
explain the benefits of the nose
~cilia and mucous membrane are present to trap foreign substances (e.g. dust, bacteria, other foreign substances)
~mucous membrane serves to moisten the air
~blood in the large number of capillaries located beneath the mucous membrane warm the air that comes through the nasal passages
~filter, warm and moisten the air
nose hairs are located
in the nostrils
pharynx
~otherwise known as the throat
~where the oral and nasal cavity join
larynx
~otherwise known as the voice box
~mainly made of cartilage (flexible connective tissue)
~two membranes stretched on the inside of the larynx known as vocal cords
~ vocal cords vibrate as air is breathed out and controlling these vibrations allow humans to make sounds
epiglottis
a "flap" that covers the larynx, so chocking doesn't occur
what is considered the first portion of the passageway that leads to the lungs?
the larynx (voice box)
trachea
~otherwise known as the windpipe
~12 centimeters long and 2.5 centimeters wide
~ kept open by horseshoe shaped rings of cartilage that are embedded in the trachea's wall
~lined with ciliated mucus cells that (cilia) move rhythmically moving mucus and other foreign substances up to the pharynx where the substances leave the air passages and are usually swallowed
how does smoking affect the trachea?
smoking stops the cilia, in the trachea, from moving (1 cigarette= 20 minutes of non-moving cilia) and tobacco smoke increases the amount of mucus in the lungs (when smokers cough, their bodies are trying to get rid of the extra mucus)
bronchi
~found in the middle of the chest
~trachea divides into two cartilage-ringed tubes (called bronchi)
~also lined with ciliated cells (like the trachea and nasal passages)
bronchioles
~group of tiny air tubes that result from the division and subdivision of bronchial tubes, resulting in the bronchial tube walls becoming thinner with less and less cartilage known as bronchioles
location of alveoli
~located at the end of each bronchiole
~tiny cup shaped cavities in an air chamber (located at the end of the bronchiole)
alveoli.... how many in lungs/surface area
~respiratory surface in humans (alveoli walls=one cell thick)
~several cup shaped cavities in an air chamber located at the end of each bronchiole
~thin, moist and surrounded by a large number of capillaries
~exchange of oxygen and carbon dioxide between blood and lung/alveoli occur through the wall of the alveoli
~300 million alveoli in lungs
~A=70 square meters (40 times more than surface area of skin)
how does smoking affect the alveoli?
smoking makes it hard for gas exchange to occur through the alveoli wall. about one third of the particles remain from smoking, though phagocytic cells called macrophages can SLOWLY remove these particles, but particles from excessive smoking or air pollution can permanently damage the alveoli, making gas exchange very difficult, inelastic scar like tissue will form on the lungs also making breathing hard, a disease known as emphysema (reduces the working area of the respiratory surface)
What are the four main stages of gas exchange in humans?
~breathing, the movement of air in and out of the lungs
~external respiration, the exchange of oxygen and carbon dioxide between the air and the blood in the lungs
~internal respiration, the exchange of oxygen and carbon dioxide between the blood in the capillaries and the body cells
~oxygen and carbon dioxide transport between the respiratory surface and the body cells
Breathing is the process of
air coming in and out of the lungs
Breathing
first stage of gas exchange in humans
inhalation
~active phase of breathing
~diaphragm contracts/moves downward
~ribs move up and outward
~lungs expand, drawing air into the lungs
~pressure within the chest cavity decreases (air moves from high pressure (outside lungs) to low pressure (within the lungs))
exhalation
~passive phase of breathing
~diaphragm expands and moves upward
~rib muscles relax and ribs relax going downward
~air is forced out of the lungs
~lungs contract
~pressure within the chest cavity increases (air moves from high pressure (lungs) to low pressure (outside the lungs))
normal breathing rate
12 to 25 times/minute
breathing: volutary/involutary?
involuntary for the most part, though it can be controlled to some extent
lungs: elastic/inelastic? explain
lungs are elastic they expand or contract based on pressure changes caused by the movement of the rib/rib muscles/diaphragm
what controls the rate of breathing?
~the respiratory center in the brain
~chemoreceptors, found in the aorta and several other large arteries, they are substances that determine levels of chemicals (e.g. oxygen and carbon dioxide) in the blood.... if there is a high level of carbon dioxide in the blood the chemoreceptors send messages to the respiratory center in the brain, stimulating the respiratory center in the brain.... the respiratory center sends impulses to the diaphragm and rib muscles to change the rate and depth of breathing decreasing the amount of carbon dioxide in the blood and increasing the amount of oxygen in the blood.
external respiration
ex.
~the exchange of oxygen and carbon dioxide between the air and the blood in the lungs
ex. oxygen, when inhaled, is in a higher concentration in the alveoli, than in the blood in the capillaries, so oxygen dissolves in the moist lining of the alveoli, and diffuses into the capillary blood, which is then pumped to the cells in the body, by the heart. on the other hand, carbon dioxide diffuses from the blood into the alveoli, and out of the lungs (opposite direction that oxygen is traveling)
internal respiration
ex.
~the exchange of oxygen and carbon dioxide between the blood in the capillaries and the body cells
ex. oxygen in the blood diffuses through the intracellular fluid into the body cells. carbon dioxide diffuses from the body cells through the intracellular fluid, into the capillary blood
oxygen and carbon dioxide diffuse based on a
concentration gradient
most oxygen from the lungs to the body tissue by
hemoglobin
hemoglobin
red, iron containing protein found in the blood
mostly carries oxygen
holds oxygen loosely
hemoglobin + oxygen =
oxyhemoglobin (HbO2)
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