Lesson 9.1: The Importance of an Organ Delivery System

Lesson 9.1: The Importance of an Organ Delivery System

Animals require a continuous supply of oxygen (O 2 ) for cellular respiration, and they must expel carbon dioxide (CO 2 ), the waste product of this process. It is important not to confuse gas exchange, the traffic of O 2 & CO 2 between the animal & its environment, with the metabolic process of cellular respiration. gas exchange supports cellular respiration by supplying O 2 & removing CO 2

The Earth s atmosphere is composed of 21% oxygen the source of oxygen, called the respiratory medium, is air for terrestrial animals, & water for aquatic animals

four activities involved 1. movement of air through the respiratory passages and lungs 2. diffusion of O 2 and CO 2 between the lungs & the blood in the transport system 3. transportation of the O 2 and CO 2 by the blood to the body cells 4. diffusion of the O 2 and CO 2 between the blood and the body cells

Breathingprocess of exchange of air between the lungs and the environment

The uptake of O 2 and the release of CO 2 by cells takes place across a respiratory membrane

Respiration-all processes involved in the exchange of O 2 and CO 2 between cells and the environment, including breathing, gas exchange, and cellular respiration

Upper Respiratory Tract oral passage partial warming & moistening of air nasal passages moistens air warms air filters air pharynx nasal pharynx oral pharynx both join to connect to the trachea & esophagus

epiglottis prevents material from entering the trachea trachea (upper region) reinforced with rings of cartilage prevents the tube from collapsing; i.e. it is always open larynx enlarged area of the trachea contains the vocal cords

Lower Respiratory Tract trachea (lower region) lined with cilia that move particles up mucous secreting cells that trap foreign matter moved out by the cilia bronchi two branches from the trachea one to left lung, one to right lung cartilage ring reinforced bronchioles further divisions of bronchi no cartilage reinforcement

terminal bronchioles final divisions of bronchioles alveoli composed of alveolar ducts and sacs at the end of the terminal bronchioles site of O 2 and CO 2 gas exchange pulmonary capillaries part of the circulatory system very small and very numerous great surface area very intimate contact with alveoli minimum diffusion distance

Air enters the body through the nasal cavity or the mouth Foreign particles are blocked entry by nasal hairs (act as a filter) Nasal cavity warms and moistens incoming air Mucus traps particles and keeps cells lining the nasal cavity moist

Nasal cavities open into the pharynx Pharynx branches into 2 openings Trachea Esophagus Trachea AKA windpipe Cilia (hair-like structures) line the trachea Debris gets swept by cilia from the trachea to the pharynx Bands of cartilage keep the trachea open

Esophagus Trachea Taken from Nucleus medical media

Enlarged section of cartilage (larynx), supports the epiglottis Larynx (AKA voicebox) The epiglottis is a flap-like structure which covers the trachea when food is being swallowed

Air from pharynx enters larynx Contains 2 thin sheets of elastic ligaments (vocal cords) Cords vibrate as air is forced past them Larynx is protected by thick cartilage (Adam s apple)

Inhaled air moves from the trachea to the 2 bronchi Carry air into the right and left lungs, where they branch into smaller airways called bronchioles Bronchiolessmallest passageways of the respiratory tract, without cartilage

The lining of the bronchi and bronchioles have ciliated cells and mucus secreting cells. cilia beat together about 20 times/s to move dirt trapping mucus toward the pharynx ensures clean air passages & alveoli

Air moves from the bronchioles into tiny sacs, alveoli Each sac is surrounded by capillaries Gases diffuse between the air and blood from high concentration to low Oxygen moves from the air in the alveoli into the capillaries CO2 moves from the capillaries into the air in the alveoli Contain one layer of cells to allow rapid gas exchange 150 million/lung

Outer surface of the lungs and the chest cavity are surrounded by the pleural membrane Space between pleural membranes is filled with fluid to reduce friction during inhalation

Dome shaped muscle, separating the chest cavity from the abdominal cavity Regulates pressure in the chest

Inhalation Diaphragm contracts, shortens and pulls down Chest volume increases and pressure in the lungs decreases P at is greater than pressure in chest, air moves into lungs Exhalation Diaphragm relaxes and returns to dome shape due to the force exerted by the organs in the abdomen Chest volume decreases and pressure increases Pressure in lungs is greater than Pat, air moves out of the lungs

Pg. 287 Questions 1-4, 6-9 Bill Nye-Part 1

9.2

Gases diffuse from high pressure to low pressure Dalton s law of partial pressure-each gas in a mixture exerts its own pressure, or partial pressure Partial pressure of oxygen in the blood depends on location

Atmospheric air follows the following path to enter the blood stream. Oral/Nasal Cavity Pharynx Larynx Trachea Bronchus Bronchioles Alveoli Blood Stream Hemoglobin-increases oxygen carrying capacity of the blood Heme (iron) and globin (protein) Each heme contains an iron atom which binds with oxygen Oxyhemoglobin-hemoglobin that is bound to oxygen, allows oxygen to be dissolved into the plasma

20 times more soluble than oxygen Small amount (9%) produced by body is carried in the plasma 27% combines with hemoglobin Majority (64%) combines with H 2 O to form carbonic acid H 2 CO 3 Carbonic anhydrase speeds up the conversion of CO 2 to H 2 CO 3 Maintains a low partial pressure of CO 2, allowing it to diffuse into the blood

Carbonic acid problematic, needs to be buffered Carbonic acid dissociates into bicarbonate ions (HCO - 3) and hydrogen ions (H + ) H 2 CO 3 H + + HCO - 3 Hemoglobin combines with hydrogen ions, neutralizing the acidity The venous blood reaches the lungs where oxygen dislodges the H + from the hemoglobin sites Free hydrogen and bicarbonate ions combine to form CO 2 and H 2 O The CO 2 is eliminated during exhalation

Three physical factors affects the rate of gas exchange across the respiratory surface... 1. the area of the respiratory surface the larger the area the greater the exchange 2. the concentration difference the greater the difference between O 2 concentrations in the air, the lungs, & in the blood, the more rapid the rate of diffusion (same principle applies for CO 2 exchange) 3. the diffusion distance the thinner the respiratory surface, the faster the rate of diffusion across it... human lung alveoli and capillaries are only one-cell thick

Pg. 288 Questions 1-2 Pg. 291 Questions1-5 Bill Nye-Part 2