3A exchange transport system Flashcards
What is each gyll made of in fish
Fin plates called Gill filaments which give big surface area for gas exchange
What are the tiny structures which cover Gill filaments
Lamellae which increases surface area even more
Why do the lamella have lots of blood capillaries
speed up the difusion
Explain counter current system for gas exchange and fish
Blood flows throughlamella in One Direction and water flows over in opposite direction
maintaining large concentration gradient between water and blood
concentration of oxygen in water is always higher than in blood so top diffusion efficiency
What do you insects use for gas exchange
Trachea
In insects what are the paws on the surface of the trachea called
Spiracles
How does gas exchange work in trachea of insects
air moves into trachea through spiracles
O2 travels down conc grad towards cells
trachea branch to tracheols which have thin permeable walls to individual cells
02 diffusers directly into respiring cells
CO2 from cells move down conc grad to spiracles to be released
What do you insects to use to move air in and out of spiracles
Rhythmic abdominal movements
Where do Dicotyledonous plants exchange gases
Surface of mesophyll cells
Brief explanation of how gas exchange works on the surface of mesophyll cells
Mesophyll cells inside the leaf- gases move in and out through stomata in the epidermis
stomata open via guard cells
How do you insects stop losing too much water
They close their spiracles using muscles
have a waterproof waxy cuticle and tiny hairs around spiracles which reduce evaporation
How does stomata prevent water loss
Water enters guard cells making them turgid which opens stomato pore
if plant gets dehydrated Guard cells lose water and become flaccid which closes pores
What are plants which are specially adapted for life in warm dry or windy habitats called
xerophytes
Examples of xerophytic adaptations
Stomata in sunken pits trapping moist air reducing conc grad of water between leaf and air reduces diffusion of water out of leaf
Hairs on epidermis trapped moist air
Curled leaves with stomata inside protect from wind
Reduced number of stomata fewer places for water to escape
Waxy waterproof cuticles on leaves reduce evaporation
Why do humans need to breathe
To get oxygen into blood for respiration to remove carbon dioxide made by respiring cells
Explain process of breathing
Air enters into trachea
trachea split into two bronchi
each bronchus then branches into bronchioles bronchials end in alveoli where gas is exchange
rib cage intercostal muscles and diaphragm all work together to move in and out
What are the two layers of intercostal muscles
Internal and external
Explain inspiration
External intercostals and diaphragm muscles contract
Causes rib cage to move upwards and outwards and diaphragm to flatten this increases volume of thoracic cavity
As volume of thoracic cavity increases lung pressure decreases
Air flows from area of higher pressure to lower pressure so airflows down trachea into lungs
Inspiration is an active process requiring energy
Explain expiration
External intercostals and diaphragm muscles relax
Rib cage moves down and inwards and diaphragm becomes curved again
Volume of thoracic cavity decreases causing air pressure to increase
Air force down pressure gradient out of lungs
Exploration is passive process
How can expiration be forced
External intercostal muscles relax and internal intercostal muscles contract pulling with cage further down
during this movement the two sets of intercostal muscles is said to be antagonistic
What is the single layer of thin flat cells which alveolus is made from
Alveolar epithelium
Describe the Alveolus
Huge number of alveoli in the lungs meaning large surface area for exchange in O2 and CO2
alveoli surrounded by network of capillaries
How does gas exchange happen in alveoli
O2 defuses out of alveoli across Alveolar epithelium and capillary endothelium and into haemoglobin in the blood
CO2 defuses into alveoli from blood and breathe out
Summarise gas exchange in humans
02 moves down trachea bronchi bronchioles into alveoli
Movement happens down a pressure gradient
alveoli -O2 defuses across Alviolar epithelium then the capillary endothelium ending up in the capillaries this movement happens down a diffusion gradient
How are alveoli adapted for gas exchange
Thin exchange surface- alveolar epithelium only one cell thick -short diffusion pathway
Large surface area -large number of alveoli
Steep concentration gradient of O2 and CO2 between the alveoli and capillaries
what is tidal volume
volume of air in each breath normal between 0.4dm3 and 0.5dm3
what is ventilation rate
number of breaths per minute normally 15
what Is forced expiratory volume
Maximum volume of air which can be breathed out in one second
What is forced vital capacity
Maximum volume of air its possible to breathe forcefully out of lungs after deep breath in
What can be used to find tidal vol ventilation rate and more
spirometer
Describe pulmonary tuberculosis
Immune system cells build wall around bacteria and lungs forming small hard lumps called tubercles
Tissue infected with tubercles dies gas exchange surface damage so tidal volume decreased
Tuberculosis causes fibrosis further reducing tidal volume
What does reduced tidal volume mean
Less Air can be inhaled with each breath and therefore patients have to breathe faster ventilation rate increases
Symptoms of tuberculosis
Persistent cough coughing up blood mucus chest pains shortness of breath and fatigue
Describe fibrosis
Formation of Scare tissue in lungs result of infection or exposure to asbestos or dust
Scar tissue thicker and less plastic than normal tissue
Meaning lungs less able to expand can’t hold as much air tidal volume reduced and so is FVC
Reduction in rate of gasseous exchange diffusion is slower across the scars
Symptoms of fibrosis
Shortness of breath dry cough chest pain fatigue weakness
What is it mean that fibrosis patients have faster ventilation rate
Can’t get enough air to lungs to oxigenate blood
Describe asthma
Respiratory condition airways become inflamed irritated usually from allergic reaction to pollen and dust
During attack smooth-muscle lining the bronchioles contracts large amount of mucus produced
Causes constriction of airways, airflow is severely reduced this oxygen enters alveoli causing FEV to reduce
Symptoms of asthma
Wheezing tight chest shortness of breath in
How do inhalers work
Drugs cause muscle in bronchioles to relax opening up the airways
describe emphysema
Caused by smoking or long-term exposure to pollution from foreign particles become trapped in alveoli
Causes inflammation attracting phagocytes these produce enzyme that breaks down elastin
Loss of elastin means alveoli can’t recoil to expel air as well
Also leads to destruction of alveoli walls -reduces surface area of alveoli -rate of gas exchange decrease
what is elastin
Protein found in the walls of the alveoli
What does elastin help with in alveoli
Causes alveoli to return to normal shape after inhaling and exhaling air
symptoms of emphysema
Shortness of breath wheezing increased ventilation rate
How can tuberculosis fibrosis asthma and emphysema cause tiredness and weakness
They reduced rate of gas exchange in alveoli less O2 able to diffuse into bloodstream body receives less o2 rate of aerobic respiration reduced therefore less energy is released
