Transcript GAS EXCHANGE
GAS EXCHANGE
GAS EXCHANGE
As you recall, all the cells of organisms carry out aerobic cellular respiration in order to release energy from food.
Remember?
C 6 H 12 O 6 + O 2 (glucose) (oxygen) CO 2 + H 2 O + ATP (carbon dioxide) (water) (energy)
C 6 H 12 O 6 + O 2 CO 2 + H 2 O + ATP (glucose) (oxygen) (carbon dioxide) (water) (energy)
• • • •
Oxygen is needed for this process.
Carbon dioxide is released from this system.
To survive, organisms must take in oxygen and expel carbon dioxide from their bodies.
This is accomplished through a process called
GAS EXCHANGE
Review of the eight life processes:
1. Respiration 2. Reproduction 3. Regulation 4. Growth 5. Excretion 6. Nutrition 7. Transport 8. Synthesis
VOCABULARY
•
Respiration:
the process of releasing chemical energy stored in foods •
Gas exchange:
the physical methods that organisms have for obtaining oxygen from their surroundings and removing excess carbon dioxide •
Respiratory surface:
surface through which gas exchange occurs between an organism and its environment
Characteristics of a Respiratory Surface
1. Thin walled for diffusion 2. Must be moist (oxygen and carbon dioxide are dissolved in solution) 3. Must be in contact with the source of oxygen 4. Must be in contact with the transport system so gases can get to all cells
Gas exchange occurs by diffusion
• As cells use up the oxygen from cellular respiration, the concentration of oxygen in the cell is
low
• The capillaries carry oxygen rich blood from the respiratory surface so the concentration of oxygen in the blood is
high.
Therefore oxygen diffuses from the blood to the cells (high to low concentration)
Therefore oxygen diffuses from the blood to the cells (high to low concentration)
O 2 O 2 O 2 O 2
Gas exchange occurs by diffusion
• The cells build up carbon dioxide as a waste product of cellular respiration • The blood has a low concentration of carbon dioxide
Therefore the carbon dioxide diffused from the cells to the blood (high to low concentration)
Therefore the carbon dioxide diffused from the cells to the blood (high to low concentration)
CO 2 CO 2 CO 2 CO 2
The greater the surface area of the respiratory surface, the greater the rate of gas exchange.
Protists have direct exchange between the cell and the environment Multicellular organisms have
specialized organs and organ systems for gas exchange.
PROTISTS:
Diffusion directly through the cell membrane
CO 2 o 2 o 2 CO 2
HYDRA
• Diffusion directly from the environment to the cells of the gastrovascular cavity and into the endoderm
CO 2
• Diffusion directly from the fresh water into the cells of the ectoderm
CO 2 O 2 CO 2 O 2 O 2
GRASSHOPPER
Blood
does not
carry gases System of branching tubes carry air to the cells • Air enters 10 pair of openings called
spiracles
• Tracheal tubes branch into smaller tubes and into fluid filled ends where there can be contact with the body cells – Here oxygen and carbon dioxide can diffuse • Air is pumped in and out of tracheal system by muscle contraction • Air sacs (connected to tubes) help pump air in and out
GRASSHOPPER
EARTHWORM
Skin is the respiratory surface • Skin is thin and specialized cells secrete mucus • Just beneath the skin is a large number of capillaries Capillaries pick up oxygen and carry it to all the cells Oxygen is deposited and carbon dioxide gets picked up and returned to the skin • If the skin dries out – they suffocate • If there is flooding rain – they drown
EARTHWORM
MULTICELLED ANIMALS:
air breathers (air is 21% oxygen) • must keep the respiratory surfaces moist • must have respiratory surfaces extending inside to protect surfaces and decrease water loss by evaporation • • most have respiratory pigments in the blood to allow the blood to carry more gases than water
hemoglobin
is the most common respiratory pigment
MULTICELLED ANIMALS:
water breathers (water has less than 1% oxygen) • less oxygen available and oxygen diffuses more slowly in water • therefore large amounts of water must pass over the respiratory surface
GAS EXCHANGE IN GILLS
• Gas exchange organ of water living organisms are
gills
• As water passes over, oxygen diffuses across to the blood vessels • A great deal of water must pass over them
ORGANISM PROTISTS (AMOEBA and PARAMECIUM) HYDRA EARTHWORM ORGAN WHERE GAS EXCHANGE TAKES PLACE ADAPTATIONS OR SPECIALIZED STRUCTURES
Cell membrane Endoderm to gastrovascular (cell membrane) Ectoderm to fresh water none none Skin Specialized cells Blood
GRASSHOPPER
Spiracles to tracheal tubes to air sacs Air sacs
FUNCTION OF SPECIAL STRUCTURES
Cell secrete mucus to keep skin moist Hemoglobin so blood carries more O 2 water than Where diffusion of gases occurs Body movements squeeze air sacs and help move air in and out of the body
General Structure
• Lungs fill a large part of the chest cavity • Chest and abdomen are separated by the diaphragm • Lungs are enclosed by the pleura
Structures
• • • The Nose Air enters through the nostrils Mucous membrane and cilia trap small particles of bacteria and dust Blood vessels are close to the surface The nose 1. Filters air 2. Moistens air 3. Warms air
The Pharynx
• The throat – common passage from the nose and the mouth
The Larynx
• The voice box is made of cartilage • Contains two pair of vocal cords • Controlled vibrations make a variety of sounds • The epiglottis blocks the larynx from food during swallowing
The Trachea
• 12 cm long and 2.5 cm wide • Kept open by horseshoe shaped rings of cartilage • Ciliated mucous membranes push particles up into the throat • Smoking stops cilia from moving and increases production of mucous
Bronchi
• Two cartilage ringed tubes that branch off the trachea to the lungs • Cilia lines the tubes • Branch into the bronchial tubes in the lungs
Bronchioles (tiny tubes)
• The smallest branches of the bronchial tubes that lead to the alveoli
BRONCHIOLE
The Alveoli
• Tiny air chambers one cell thick • Walls are moist and surrounded by capillaries • Site of gas exchange or external respiration • 300,000,000 alveoli • 70 square meters of surface area (40 x’s the surface area of the skin)
Fill in the diagram on page 10. in the packet
1. Nose 2. Nasal passage 3. Pharynx 4. Epiglottis 5. Larynx 6. Esophagus 7. Trachea 8. Lung (or pleura) 9. Pleura 10. Bronchi 11.Bronchioles
12.Diaphragm
13.Alveoli (air sacs) 14.Capillaries (blood vessels) 15.Capillary beds 16.Bronchioles
17.Alveoli
RESPIRATORY SYSTEM PARTS AND FUNCTIONS Nose • Air enters • Hair filters out dust, dirt, and bacteria Nasal chamber • Warms and moistens air Pharynx (throat) • Passage to the trachea Epiglottis • Flap that closes over trachea • Keeps food and liquid out of the lungs Esophagus • Tube to the stomach
RESPIRATORY SYSTEM PARTS AND FUNCTIONS Trachea (wind pipe) • Tube that carries air from the pharynx to the bronchi • Ciliated and has cartilage rings Bronchi (2 bronchi) • Short tubes from the trachea into the right and left lungs Bronchioles • Tiny tubes • Carry air from the bronchi to the alveoli Lung • Main organ of respiration • Contains tiny air sacs (alveoli) and capillaries
RESPIRATORY SYSTEM PARTS AND FUNCTIONS Diaphragm • Muscle below the chest cavity • Moves down with inhalation (contracts) • Moves up with exhalation (relaxes) Capillaries • Surrounds the alveoli • SITE OF GAS EXCHANGE Alveoli • Air sacs • SITE OF GAS EXCHANGE
THE FOUR PHASES OF HUMAN RESPIRATION
THE FOUR PHASES OF HUMAN RESPIRATION
I. BREATHING II. EXTERNAL RESPIRATION III. INTERNAL RESPIRATION IV. CELLULAR RESPIRATION
I. BREATHING
Movement of air into and out of the lungs
Inhalation: •
Ribs up and out
•
Diaphragm pulls down
•
Air rushes in
Exhalation • • •
Ribs relax and drop down Diaphragm moves up Air pushed out
No muscles in the lungs, they are elastic and air is moved due to pressure changes • • Breathing controlled by
Respiratory center in the brain Sensors in the aorta and other arteries that sense gas levels
II. EXTERNAL RESPIRATION
Exchange of oxygen and carbon dioxide between lungs (alveoli) and blood
• Air flow moves with the concentration gradient
III. INTERNAL RESPIRATION
Exchange of oxygen and carbon dioxide between blood and tissues (body cells)
• Exchange by diffusion
III. INTERNAL RESPIRATION
Exchange of oxygen and carbon dioxide between blood and tissues (body cells)
Exchange by diffusion O 2
CO 2
O 2 O 2
CO 2 CO 2
O 2
CO 2
IV. CELLULAR RESPIRATION
Using oxygen, the cells release energy (ATP) from food (glucose)
TRANSPORT OF GASES IN BLOOD
Oxygenated blood must be transported from the lungs to all the cells of the body
TRANSPORT OF OXYGEN
• Hemoglobin (Hb) carries O 2 cells on red blood • Hb + O 2 = oxyhemoglobin (HbO 2 ) with a loose bond • CO has a stronger bond with hemoglobin than O 2 therefore cigarette smokers’ blood carries less O 2 than non smokers’ blood
TRANSPORT OF CARBON DIOXIDE
70% carried by water CO 2 + H 2 O H 2 CO 3 H 2 CO 3 H + HCO 3 20% carried by hemoglobin Hb + CO 2 HbCO 2 10% dissolves in plasma
PHASES OF RESPIRATION
BREATHING AIR O 2 in / CO 2 → EXT. RESP → TRANSPORT → INT. RESP ALVEOLI – CAPILLARY out BLOOD → CELL RESP CAPILLARY – TISSUES AEROBIC RESP
BREATHING AIR O 2 in / CO 2 out → EXT. RESP → TRANSPORT ALVEOLI –CAPILLARY → INT. RESP → CAPILLARY – TISSUES → CELLULAR RESPIRATION BLOOD FLOW
BREATHING
DIAPHRAGM RIB CAGE SIZE OF CHEST CAVITY AIR MOVEMENT PRESSURE INHALATION EXHALATION
INHALE
CONTRACTS / MOVES DOWN UP AND OUT INCREASES INTO LUNGS LOWER IN LUNGS
EXHALE
RELAXES / MOVES UP DOWN AND IN DECREASES OUT OF LUNGS HIGHER IN LUNGS
DISEASES OF THE RESPIRATORY SYSTEM
ASTHMA
• Chronic inflammation of the bronchi • Response to irritants with shortness of breath, coughing, and wheezing • Treated with medications and inhalers
Asthma
BRONCHITIS
• Inflammation of the lining of the lower respiratory passages (bronchi and bronchioles) • Mucus production increases and impairs breathing • Risk of lung infection (pneumonia) increases
Chronic Bronchitis
EMPHYSEMA
• Alveoli enlarge as the walls between the alveoli break down (airways collapse) • Chronic inflammation causes lungs to lose elasticity • It takes a large amount of energy just to breath • Over inflation of the lungs leads to a permanently expanded barrel chest
emphysema lungs A normal lung
PNEUMONIA
• Infection in the lungs • Caused by – Bacteria (treatable with antibiotics) – Virus – fungus
Pneumonia
LUNG CANCER
• Accounts for 1/3 of all cancer deaths in the United States • Second-hand smoke is the third leading cause of preventable death in America • Many have no symptoms in the early stages • Increased incidence associated with smoking (8 out of 10 lung cancers are caused by smoking)