Unit 4 Part 1 Flashcards
Gas exchange
What happens to the surface area to volume ratio as an organism gets larger?
It changes - decreases
What limits and organism’s ability to take in and release substance?
Its outer surface area layer
What can rely on direct exchange of respiratory gasses with their environment?
Only the smallest organisms
What do non small organisms rely on to get oxygen to internal tissues and take carbon DI away?
On anatomical and physiological adaptations
Where are specialized tissues found?
- Skin of some organisms
- Gills of many aquatic organisms
- Lungs of some large terrestrial organisms
What are gas exchange surfaces characterized by?
- Being thin to keep diffusion distances shorter - Usually one cell layer
- Being moist to encourage gas diffusion
- Having large surface area for max diffusion
- Being permeable to respiratory gasses - Oxygen + Carbon DI
What must concentration gradients be maintained for?
For oxygen to diffuse into blood and carbon DI out of blood
What is exothermic?
Cold blooded
What species are exothermic?
All animals that use gills
What is endothermic?
Warm blooded
What do capillaries do?
They are the only blood vessels that permit the exchange of substances
How thick are capillaries?
Only one cell thick
What’s the difference between the levels of blood that leaves body tissues vs levels of blood before it reaches the active body tissue?
Blood that leaves body tissues has a higher concentration of carbon DI + lower concentration of oxygen compared to levels before the blood reached the active body tissues
Where has blood that is first circulated to the gills been?
W/in capillaries of the muscles and other body tissue
Concentration of oxygen and carbon DI in lung capillaries
Oxygen: Lower than the air inspired
Carbon DI: Higher than the air inspired
What are the two events that must occur to keep concentration gradients in place?
- Water/air must be continuously passed over/refressed (ventilated) in the gills/ lungs
- There must be a continuous blood flow to blood vessels in both the body tissues and tissues of gills or lungs
What are the alveoli?
Microscopic spheres
- Tiny air sacs
What are the alveolus?
singular alveoli
- A terminal end of one of the branches of bronchioles
What did alveolus start off as?
The trachea
What is a surfactant?
Thin phospholipid and protein film that lines the inner surface of each alveolus
What does the surfactant do?
Reduces the surface tension of the moist inner surface + helps prevent each alveolus from collapsing each time air is expired
What are the bronchioles?
Small tubes that connect to the subdivided millions of spherical alveoli
What does the spherical shape of the alveoli provide?
A vast surface area for the diffusion of oxygen and carbon DI
What type of tissue makes up our lungs?
Passive
What are the muscles surrounding the lungs?
Diaphragm, muscles for the abdomen, and external and internal intercostal muscles
What does Boyle’s law state?
” An increase in volume will lead to a decrease in pressure, and vice versa”
Where are the lungs located?
Inside the thorax/ thoracic cavity
- which only has one opening through the trachea
What is the diaphragm?
Large, Dome-shaped muscle that forms the “floor” of thorax
What happens when a diaphragm contracts?
It flattens the dome shape + increases volume of thorax
What is a spirometer?
A device used to measure lung volume
What are the volumes that a spirometer can measure?
- Tidal volume
- Inspiratory reserve volume
- Expiratory reserve volume
- Vital capacity
What is tidal volume?
Volume of air that’s breathed in or out during a normal cycle
What is Inspiratory reserve volume?
Max volume of air that a person can breathe in
What is Expiratory reserve volume?
Max volume of air a person can breathe out
What is vital capacity?
Sum of Inspiratory reserve volume, tidal, and expiratory
Adaptations of a leaf
- Waxy cuticle
- Upper + Lower epidermis
- Palisade mesophyll
- Spongy mesophyll
- Veins
- Stomata
Waxy cuticle adaptation
Covers epidermis cells and reduces evaporation
Epidermis cells adaptations
Found on the upper and lower surface of leaves that secrete a waxy cuticle and are transparent allowing lights into mesophyll cells where photosynthesis happens
- Guard cells forming stomata are on lower epidermis
Palisade mesophyll adaptations
Densely packed region of cylindrical cell in upper portion of leaf
Spongy mesophyll adapation
Loose packed cells located below the palisade layer and above stomata
- Few chloroplasts and air spaces around palisade increase surface area for gas exchange
Air space adaptation
Facilitates diffusion of gasses between surrounding atmospheres and mesophyll cells
Stomata adaptation
Pores that allow gasses to enter and leave cell
- More common on lower epidermis of leaves and are opened and closed by guard cells
Veins adapation
Encloses fluid transport tube; xylem and phloem are located centrally w/in a leaf to give access to all cell layers
What does water do in xylem?
Moves up from root stems to the leaf
What does water do in Phloem?
Water and dissolved sugar are distributed to other parts of plants
What is transpiration?
The evaporation of water through open stomata
How can number of stomata be expressed?
mm^-2 or μm^-2
What are erythrocytes?
Blood cells
- A plasma membrane surrounding cytoplasm filled w/ Haemoglobin molecules
What are haemoglobin molecules capable of?
Of reversibly binding to both oxygen and carbon DI molecules
Which atom is binding when haemoglobin is binding to oxygen
the iron atom
What is cooperative binding?
When any oxygen molecule is bonded to a haemoglobin increasing its attraction for more oxygen
What is allostery?
Binding of carbon DI to polypeptide chains of haemoglobin and resulting change in haemoglobins affinity for oxygen
What is the allosteric site?
Area of each polypeptide when carbon DI binds
What is bohr shift?
The binding of carbon DI to haemoglobin resulting in an increase in the release of oxygen molecules and decrease for affinity of oxygen
What is haemoglobin job?
Uses cooperative binding of oxygen molecules to ensure sufficient oxygen is brought to respiring tissue
features of erythrocytes
- Biconcave shape
- Each contain 300M haemoglobin molecules
- No nucleus = More space to carry haemoglobin
Structure if type 1 pnuemocytes?
Extremely thin (0.1-0.2 μm thick) and have a large surface area
What is the function of Type II pneumocytes?
Secrete pulmonary surfactant and can differentiate into Type I pneumocytes
Air inspired into alveoli?
Oxygen: higher concentration
carbon do: Lower concentration
