3.1 Exchange And Trasnport Flashcards
What happens to a animals exchange surface as it gets larger?
- their cells are too far from the exchange and membranes or surfaces for substances to simplify diffuse across
- so they need special exchanges surfaces (eg. Lungs )
What can single celled organisms do?
- they can exchange across outer surfaces
- due to a large SA:V
What special about larger organisms when exchanging substances?
- as they are more active they need special ways as they demand more ( eg. 02 )
- travel long distances
What is an exchange surface?
An exchange surface is a specialised area that is adapted to make it easier for molecules to cross from one die to another
- eg alveoli and root hair cells
What makes an exchange system efficient ?
- a large SA, this allows more movement of particles across the cell
- a thin layer, this allows for a short diffusion distance
- maintain a good concentration gradient, as this allows for a good blood supply and ventilation
What is the passage of airway through the gas exchange system?
- trachea, which divides into two
-bronchi, which further divides - bronchioles, which terminate into millions of alveoli
Explain how the alveoli create a surface for efficient gaseous exchange
- wall is one cell thick for shorter
diffusion distance - squamous epithelium provide
short diffusion distance
3.elastic in walls can recoil to expel air which helps
ventilation - ventilation maintains concentration
gradient
5.large number of alveoli provide large
surface area
6.small size alveoli provide larger
surface area to volume ratio
Why does air move into and out of the lungs?
differences in volume and pressure
Ventilation
Movement of air in and out of the lungs
Function of Trachea ( what does it contain )
allows air to reach lungs. contains c-shaped rings of cartilage, smooth muscle, elastic fibres, goblet cells, ciliated epithelium.
function of Cartilage
strong connective tissue that supports the trachea and bronchi. it is found in rings (so when the pressure drops the trachea doesn’t collapse)
Ciliated epithelium. what do they prevent
Cilia on epithelium that line the airways can beat/waft mucus up the airways away from the alveoli.
The mucus traps bacteria or pathogens, which prevents lung infections.
Goblet cells
Unicellular exocrine glands that secrete mucus. they line the trachea, bronchi and bronchioles.
function of elastic fibres?
They are found in the trachea, bronchi and bronchioles. Elasticity is needed for the lungs to recoil to push air out
function of smooth muscle?
also found in the trachea, bronchi and bronchioles. It controls the diameter of the airways as the muscle can contract and relax.
Contraction narrows the lumen, restricting air flow. this is important if harmful substances are present.
It can also relax, to make tubes wider during exercise. This means there is less resistance to airflow so air can enter lungs more easily.
Bronchus
similar to trachea but have a smaller diameter and thin walls. contain complete rings of cartilage, smooth muscle, elastic fibres, goblet cells and ciliated epithelium
Bronchioles
Airways in the lungs that lead from the bronchi to the alveoli. Airways in the lungs that lead from the bronchi to the alveoli.
what do large bronchioles contain
no cartilage as more self-supporting, they contain elastic and muscle fibres so can adjust the diameter to increase the airflow. do contain ciliatated epithelium
what do smaller bronchioles contain?
smooth muscle and elastic fibres, no goblet cells and no cilia on epithelium
what do smallest bronchioles contain
elastic fibres, no smooth muscle, no goblet or cilia
Alveoli
tiny sacs of lung tissue specialized for the movement of gases between air and blood
Elastic recoil
tendency for the lungs to reduce in volume after being stretched or expanded
Inspiration
The process of actively contracting the inspiratory muscles to move air into the body
Thorax
The body region between the head and the abdomen
Expiration
The process of actively or passively relaxing the inspiratory muscles to move air out of the body.
Diaphragm
Large, flat muscle at the bottom of the chest cavity that helps with breathing
Peak flow meter
Portable instrument used to measure how fast air can be pushed out of the lung
Vitalograph
Patient blows out quickly causing a peak to test the capacity of the lungs. A more sophisticated version of a peak flow meter.
Spirometer
an instrument for measuring the volume of air entering and leaving the lungs.
Tidal volume
Amount of air that moves in and out of the lungs during a normal breath
Vital capacity
the amount of air you can forcibly exhale from your lungs.
Inspiratory reserve volume
Amount of air that can be forcefully inhaled after a normal tidal volume inhalation
Expiratory reserve volume
Amount of air that can be forcefully exhaled after a normal tidal volume exhalation
Residual volume
Amount of air remaining in the lungs after a forced exhalation
Total lung capacity
sum of the residual volume and the forced vital capacity
Exoskeleton
A body covering, typically made of chitin, that provides support and protection
Spiracles
breathing tubes of insects located on abdomen
Tracheae
tiny tubes in insect body that deliver oxygen directly to metabolizing tissues
Tracheal fluid
The fluid found at the ends of the tracheoles in the tracheal system
Limits the penetration of air for diffusion
Mechanical ventilation
Forceful movement of gasses through the tracheae
Gills
Organs that remove oxygen from the water and carbon dioxide from the blood
Operculum
A protective flap that covers the gills of fishes
Gill lamellae
At right angle to gill filaments, which increase the surface area of the gills.
Gill filaments
The thin projection of a fish gill where gas exchange takes place
Gill plates
Stacks of gill filaments
Buccal cavity
the space between the lips and the gums and teeth; the vestibule of the oral cavity.
Gill arches
A supporting structure of fish gills
what is the mechanism of inspiration?
air is inhaled, intercostal muscles contract so rib cage is raised, diaphragm contracts and moves down, the volume of the thoraic cavity increases and pressure decreases below atmospheric pressure in lungs.
what is the mechanism of exhalation?
intercostal muscles relax lowering the rib cage, diaphragm relaxes and moves up, so the volume of the thoracic cavity decreases and the pressure increases above the atmospheric pressure above the lungs, the lungs recoil due to their elasticity, air is pushed out of the lungs
why is there a drop in O2 concentration in a spirometer over time?
air is re-breathed in and respiration occurs, causing carbon dioxide to be released.
structure of a bony fish gas exchange system?
the gills are gas exchange organs, they contain gill filaments and gill lamellae. gill lamellae increase surface area and are well supplied with blood vessels with thin surface.
what is the ventilation mechanism for bony fish?
water enters through the buccal cavity, which increases the volume of the cavity and lowers the pressure. water is sucked in. when the fish closes it’s mouth, the buccal cavity is raised so the volume decreases and the pressure increases, so water is forced out of the cavity across the gill filaments. each gill is covered by the operculum (bony flap) that opens when pressure increases so water can leave
how does the counter-current flow work?
the blood flow through the gill lamellae is opposite direction to the flow of water over the gills.
what is the importance of counter-current flow?
blood constantly encounters water with a higher oxygen concentration, so it maintains diffusion gradient at all times
what is the issue of a concurrent flow?
blood flows through the gills in the same direction as the water does. equilibrium is reached partway across the gill, so diffusion is the way.
Explain the gas exchange system in insects
tracheal system: air moves into tracheae through spiracles (pores on insect’s surface). the tracheae branch into tranchioles that contain fluid that oxygen dissolves in. oxygen diffuses into body cells by fluid down a concentration gradient. carbon dioxide diffuses out.
how do insects move air in and out of spiracles
Rhythmic abdominal movements to change the volume of their bodies
what are the adaptations of insect’s tracheal system
tracheae give large surface area. tracheole lined with single layer of cells to reduce diffusion distance
