4- gas exchange Flashcards
1
Q
gas exchange in insects- structure
A
- spiracles: external openings that act as entry and exit points for gases
- trachea and tracheoles: spiracles lead to larger tubes called tracheae, which further divide into minute tubes, the tracheoles, reaching individual cells
- air sacs: air sacs act as air reservoirs or bellows. they increase the volume of air moved through the respiratory system. they have flexible walls so that changes in pressure caused by ventilating movements of the abdomen inflate and deflate them
2
Q
gas exchange in insects- adaptation
A
- direct delivery: the tracheal system enables direct oxygen delivery to tissues, bypassing the need for a circulatory system for oxygen transport
- passive diffusion: gas exchange happens by passive diffusion, requiring no energy
- spiracle regulation: insects can control the opening and closing of spiracles to reduce water loss
3
Q
gas exchange in insects- process
A
- entry of air: air enters the body through spiracles
- oxygen transportation: oxygen travels down the tracheae and tracheoles
- diffusion: oxygen diffuses directly into the body cells and carbon dioxide diffuses out
4
Q
gas exchange in fish- structure
A
- gills: fish have gills, located on either side of the fish’s pharynx
- gill filaments: each gill has many long, thin gill filaments that increase the surface area
- gill lamellae: each gill filament is covered with thousands of tiny lamellae, which further increase the surface area for gas exchange
5
Q
gas exchange in fish- adaptation
A
- large surface area: the vast surface area provided by the gill filaments and lamellae facilitates efficient gas exchange
- thin walls: gills possess thin walls, enabling quick and effective diffusion of gases
- counter- current flow: fish utilise a counter-current flow system where the blood in the gill capillaries flows in the opposite direction to the water passing over the gills, maintaining a constant concentration gradient for maximum oxygen uptake
6
Q
gas exchange in fish- process
A
- water intake: fish intake water containing dissolved oxygen through their mouths
- passage over gills: this water then passes over the gills
- diffusion: oxygen diffuses from the water into the fish’s bloodstream, while carbon dioxide produced by the fish’s metabolic activities diffuses out into the water
7
Q
gas exchange in mammals- structure
A
- lungs: mammals have a pair of lungs, each divided into lobes
- bronchi and bronchioles: air enters the lungs through the trachea, which divides into two bronchi, each leading to a lung. bronchi further divide into smaller bronchioles
- alveoli: bronchioles end in tiny air sacs known as alveoli, where gas exchange occurs
8
Q
gas exchange in mammals- adaptation
A
- large surface area: the alveoli provide a vast surface area for gas exchange
- thin walls: alveoli have extremely thin walls, allowing for efficient gas exchange
- rich blood supply: a dense network of capillaries surrounds each alveolus, promoting faster gas exchange
- moist lining: the moist lining of the alveoli helps in dissolution and diffusion of gases
9
Q
gas exchange in mammals- inhalation process
A
- intercoastal muscles contract -> ribs move up and out
- diaphragm contracts -> moves downwards
- thorax expands -> pressure decreases -> air moves into lungs
- oxygen rich air is inhaled into the lungs, travelling down the trachea, bronchi and bronchioles to reach the alveoli
10
Q
gas exchange in mammals- diffusion in alveoli
A
- oxygen diffuses across the walls of the alveoli and capillaries into the blood
- simultaneously, carbon dioxide diffuses from the blood into the alveoli
11
Q
gas exchange in mammals- exhalation
A
carbon dioxide- rich air is exhaled, completing the gas exchange process
12
Q
waxy cuticle in leaf
A
prevents water loss
13
Q
upper epidermis in leaf
A
transparent layer allowing maximum light penetration
14
Q
palisade mesophyll layer in leaf
A
vertically stacked cells with high chloroplast count
15
Q
spongy mesophyll layer in leaf
A
contains air spaces for increased surface area, for gas exchange
16
Q
lower epidermis, guard cells and stomata in leaf
A
guard cells regulate the stomata’s opening and closing to prevent excessive water loss
17
Q
photosynthesis and respiration in plants
A
- during daytime, stomata open when conditions favour photosynthesis
- opening of the stomata allows carbon dioxide in and oxygen out
18
Q
stomata opening mechanism
A
K+ ions move into the guard cells via active transport, causing water to follow by osmosis due to decreased water potential. this makes guard cells turgid, leading to the stomata opening
19
Q
lenticels in woody plants
A
area of loosely arranged cells acting as pores in lignified (woody) plants
20
Q
lenticels function
A
enable gas exchange in woody plants
21
Q
label
A
22
Q
structure of the heart- chambers
A
four chambers- two upper atria, two lower ventricles
23
Q
structure of heart- valve system
A
- regulates blood flow and prevents back flow of blood
- atrioventricular valves: tricuspid (right) bicuspid/mitral (left), tendinous chords prevent atrioventricular valves from turning inside out due to the pressure when the heart contracts
- semilunar valves- pulmonary (right), aortic (left)
24
Q
structure of heart- septum
A
- composed of muscle and connective tissue
- prevents oxygenated and deoxygenated blood from mixing
25
structure of heart- myocardium
- cardiac muscle
- the muscular wall of the heart
- thicker in the left as a higher pressure is needed to pump blood around the body
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structure of the heart- pericardium
- the protective outer layer
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structure of the heart- coronary arteries and veins
- wrapped around the heart
- supply the heart muscle with blood
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structure of the heart- arteries
- thick muscular walls: adapted to withstand high blood pressure
- small lumen: helps maintain the high pressure
- elastic fibres: allow the arteries to stretch and recoil with every heartbeat, smoothing out the pressure surges caused by the hearts contractions
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structure of the heart- veins
- thinner, less muscular walls: adapted for a lower pressure environment
- larger lumen: facilitates the flow of blood despite the low pressure
- presence of valves: prevent back flow of blood, ensuring unidirectional flow towards the heart
- veins located between muscles: muscle contractions help squeeze the veins, pushing the blood along
30
structure of heart- capillaries
- single cell thick wall: allows quick and efficient exchange of gases, nutrients and waste
- small diameter- ensures that cells are never far from a capillary, allowing rapid diffusion
- large surface area: facilitates the exchange of materials
- slow blood flow: allows more time for exchange of materials
31
double circulatory system
- high pressure blood pump: facilitates the pumping of blood to the body at a higher pressure, thereby ensuring efficient delivery of nutrients and oxygen to all body cells
- seperation of blood types: separates oxygenated and deoxygenated blood, preventing the mixing of oxygen rich and oxygen poor blood, for more efficient oxygen delivery to tissues
32
advantages of double circulatory system
- blood pressure to the body tissues is higher
- blood pressure to the lungs is lower which avoids damaging the capillaries in the lungs and increases time for gas exchange
- concentration gradient is maintained, as oxygenated and deoxygenated blood don’t mix
- organisms can develop larger bodies
33
single circulatory system in bony fish
- lower blood pressure: in a single circulatory system, the blood is pumped at a lower pressure, which may result in less efficient nutrient and oxygen delivery
- blood mixing: in a single circulatory system, oxygenated and deoxygenated blood can mix, which decreases the overall efficiency of oxygen delivery to the body’s tissues
34
order of cardiac cycle
atrial systole -> ventricular systole -> diastole
35
atrial systole
- the stage where the atria contact, pushing blood into the ventricles
36
ventricular systole
- the stage where the ventricles contact, pushing blood out of the heart and into the arteries
- isovolumetric contraction: early phase where pressure builds with all valves closed
- ejection phase: high pressure opens semilunar valves, blood is ejected to the aorta and pulmonary artery
37
diastole
the period of relaxation where the heart fills with blood
38
label
39
myogenic stimulation of the heart
- the hearts ability to contract is myogenic, meaning it does not need external signals
- sinoatrial node (SAN): initiates the electrical signal causing heart contraction
- atrioventricular node (AVN): receives the signal from the SAN and after a short delay to allow the atria to contact, sends it in to the ventricles
- bundle of his: carries the electrical signal down the AVN down the inter-ventricular septum. it then branches into the left and right bundle branches, which lead to the Purkinje fibres, triggering ventricular contraction
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sequence of the heartbeat
- initiation: the SAN sends an electrical signal that spreads across the atria causing them to contract (atrial systole)
- delay at AVN: the signal reaches the AVN where it is delayed, allowing the atria to finish contracting and ventricles to fill with blood
- conduction to ventricles: the signal is transmitted down the Bundle of His, through the bundle branches, and into Purkinje fibres, causing ventricles to contract (ventricular systole)
- relaxation: once the signal has passed, the heart muscles relaxes (diastole) before the next cycle begins
42
importance of myogenic stimulation
- autonomy: the heart can regulate its own rhythm, independant any of the nervous system
- consistency: provides a steady and consistent heartbeat, for effective blood circulation
- adaptability: while myogenic, the heart rate can still be adjusted in response to the body’s needs, via the autonomic nervous system
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label
44
what is an ECG
an electrocardiogram is a graphical representation of the electrical activity of the heart
45
P wave of ECG
- atrial depolarisation (contraction) by a wave of depolarisation from the SAN
- start of atrial systole
46
QRS complex of ECG
- ventricular depolarisation (contraction)
- atrial repolarisation (relaxation)
- Q = bundle of His/ Purkinje fibres excitation
- R = start of ventricular systole
- S = ventricles fully contracted
47
T wave in ECG
- ventricular repolarisation (relaxation)
- diastole
48
pressure changes during the cardiac cycle
- atrial systole: a small increase in pressure as the atria contract and push blood into the ventricles
- ventricular systole: a significant increase in pressure as the ventricles contract, pushing blood into the pulmonary artery and aorta
- diastole: decrease in pressure as the heart relaxes and refills with blood. the pressure in the ventricles is lower than in the atria, which allows them to fill with blood
49
interpreting data from ECG and pressure charts
- correlation of ECG and pressure changes: the peaks in an ECG (P wave, QRS complex, T wave) should correspond with changes in pressure within the heart
- heart rate calculation: the distance between consecutive QRS complexes in an ECG can be used to calculate the heart rate
- diagnosing heart conditions: abnormalities in the ECG trace or pressure changes can indicate heart conditions, such as arrhythmia, heart block or myocardial infarction
50
importance of ECG and pressure data
- disease detection: can help identify and diagnose heart diseases and conditions
- monitoring heart health: provides valuable information about the hearts electrical activity and blood pressure, essential indicators of heart heath
- guide treatment: can inform treatment decisions and monitor the effectiveness of interventions
