B3: Transport Flashcards
Where is the pharynx?
Where oesophegous and trachea join
What is the plurae?
Sac which surrounds the lungs
What is the process of quiet expiration?
- Diaphragm relaxes & moves up and in
- Internal ICM contract, external ICM relax
- Volume decreases, pressure increases, so air moves out
What is the process of inhalation?
- Diaphragm contracts & moves down and out
- External ICM contract, internal ICM relax
- Volume increases, pressure decreases, so air moves in
What is the process of forced expiration?
- Diaphragm relaxes & moves in and up
- Internal ICM contract, external ICM relax (more forcefully)
- Abdominal muscles contract to push diaphragm upwards forcefully
- Volume decreases, pressure increases, so air moves out quickly
What is total lung capacity?
Total volume of air in your lungs
What is forced vital capacity?
Volume of air you can forcibly exhale
What is residual volume?
The leftover air after forcibly exhaling
What is tidal volume?
Volume of air which moves in and out of lungs with each normal breath
What is inspiratory reserve?
The additional volume of air you can inhale after a normal breath
What is expiratory reserve?
The additional air you can exhale after a normal breath
How does age affect lung capacity?
Lung capacity increases up until 25 years old, can begin to decline later in life
How does body composition affect lung capacity?
Larger people have larger lung capacities
How does sex affect lung capacity?
Males tend to have larger lung capacities
What is haemoglobin?
A protein in red blood cells found in vertebrates
What is the name of the complex formed when haemoglobin is binded to oxygen?
Oxyhaemoglobin complex
Describe the structure of haemoglobin
Quarternary structure of 4 haem groups which have Iron (II) ions at their centres.
Why does foetal haemoglobin have higher affinity to oxygen than adult haemoglobin?
Has a quarternary structure of two alpha and two gamma polypeptide chains whereas adult haemoglobin has two alpha and two beta.
Gamma polypeptides have a higher oxygen affinity than Beta polypeptides
What are typical adaptations of gas exchange surfaces?
Large SA - more membrane surface for gases to diffuse across
Permeable - quicker diffusion
Thin - shorter diffusion distance?
Moist - gasses can disolve
Adaptations to maintain steep concentration gradients
Dense network of blood vessels - more opportunity for gas exchange
Continous blood flow - transports substances away from diffusion site to prevent equilibrium
Ventilation - ensures desired gases are moving across exchange surfaces
Double circulatory system in mammals - separates oxygenated and deoxygenated blood to make sure oxyenated does not pass by alveoli
Features of the mammalian lungs which assist in gas exchange
- Trachea lined with cillia and mucus to trap and expell foreign matter
- Bronchi contain smooth muscle which are innervated to control air flow
Which side of the lungs is larger and why?
Right lung larger - 3 lobes (left lung has only 2) because of heart placement
Define diffusion
Net random movement of particles from a region of high to low concentration down a concentration gradient
What is the process of cooperative binding of oxgen to haem groups
- When one oxygen binds to a haem group, it causes a conformational change in the molecule and increases affinity to oxygen of other haem groups
- When an O2 is released from haem, a conformational change occurs and affinity to O2 of other haem groups decreases, so other O2 molecules are easily released
What are the x and y axes of the oxygen dissociation curve
X axis - Oxygen partial pressure (amount of oxxygen in blood)
Y axis - % Oxygen saturation (% of haemoglobins which have the max amount of O2 bonded)
Where are the lungs and tissue cells found on the oxygen dissociation curve?
Lungs - at point with high partial pressure and saturation of oxygen
Cells - at point with relatively low partial pressure and saturation of oxygen
How does carbon bind to haemoglobin?
Binds to the allosteric site and forms a carbaminohaemoglobin
How does the allosteric binding of CO2 to haemoglobin change the molecule and why is it important?
Causes a conformational change which results in a lower affinity to oygen.
- Important because it ensures that O2 is not removed from areas which require it, such as exercising tissues.
What is the Bohr shift?
When the OD curve shifts to the right due to:
- an increase in CO2 levels
- causing pH to decrease (CO2 is acidic)
- causing haemoglobin to change shape and decrease O2 affinity
- So more O2 is unloaded at respiring tissues
How does affinity and oxygen saturation change when the OD curve shifts left?
Higher overall affinity to oxygen, and oxygen saturation can remain the same at lower O2 pressures
Which species have a left shift in the OD curve?
Species which live in low O2 environments, such as the foetus or species living at high altitudes
Do species with high metabolic rates have a right or left shift in OD curve?
Right shift, because they need more O2 and more can be unloaded at respiring tissues
How are leaves adapted to gas exchange? (1 point)
Loosely packed spongy mesophyll cells - creating air pockets which are in contact w/ cells to transport gases in and out.
What is the process of transpiration? (5 steps)
- Water evaporates from spongy mesophyll cells through stomata
- Water passes from xylem vessels into leaf cells due to osmosis
- Which pulls water in xylem up
- Water moves from root cortex to xylem to replace water which moved up
- Water moves from coil to root hair cells to replace water which entered xylem
Why are stomata found on underside of leaf?
No direct sunlight, so cooler and less evaporation happens, so less water loss
What is the purpose of transpiration
- Provide water to palisade mesophyll cells for photosynthesis
- Water has a cooling effect on plant
- Water carries essential mineral salts dissolved
What is the formula for calculating stomatal density?
Number of stomata in field of view / Area of field of view
Which features of capillaries are adapted to their functions?
One cell thick walls - decreased diffusion distance
Small diameter of lumen - allows for passage of only one red blood cell at a type to optimise exchange of materials
Surrounded by basement membrane - only permeable to certain necessary materials
May contain pores - further aids substance exchange
What is the structure of a capillary?
Lumen on inside, then endothelial layer surrounding it, then basement membrane on the outside
What are the two types of capillaries and how do they differ?
Continous - no pores - limits permiability of large molecules
Fenestrated - contains pores to allow diffusion of larger molecules
Give an example of the types of tissues in the body where fenestrated capillaries are found.
Tissue specialised for absorption (e.g. intestines, kidneys)
Which features of arteries are adapted to their functions?
Thick cell walls containing an outer layer of collagen - prevent artery rupturing since blood is at high pressures
Narrow lumen - maintains high blood pressure
Contains inner layer of muscle and elastic tissue - maintains the pusle flow since they can contract and stretch
What are the different sections of the arterial wall called?
Tunica intima - the inner layer
Tunica media
Tunica externa - the outer layer
Decribe how blood flows through arteries
- Blood flows in surges upon ventricular contraction
- Elastic fibres allow wall to stretch when a pulse surges, then when it pass the wall squeezes back into place (elastic recoil) which pushes blood forwards
How else do veins and arteries differ?
Arteries have a corrugated inner surface, veins do not
Veins can be circular or flattened, arteries are always circular
In arteries, fibres are visible in the walls, whereas in veins they are not
Which features of veins are adapted to their functions?
Wide lumen relative to wall thickness - maximise blood flow for effective return of deoxygenated blood
Thin wall with less muscle & elastic tissue - not neccesary since blood at low pressures
Valves present - prevent backflow of blood since it can pool in the lowest extremities
How do pocket valves function?
- Are open when blood is flowing in the right direction towards the heart
- If blood starts going the wrong way, they are forced shut and redirect blood
What are the different layers of the vein wall?
Inner layer of endothelial cells, middle thin layer of muscle and elastic tissue, outer layer of collagen
How does blood flow in the veins?
Veins usually pass between skeletal muscle tissues, which contract and compress the vein to push the blood.
Thin walls are advantageous so vein can be easily compressed
What causes coronary occlusion?
Antherosclerosis - hardening and narrowing of arteries due to cholesterol deposition
What are the steps of coronary occlusion? (6 steps)
- Fatty deposits (atheromas) develop in arteries and narrow the lumen
- Smaller lumen restricts blood flow & increases pressure, which leads to damaged arterial wall
- Damaged site repaired with fibrous tissue which reduces elasticity of wall
- Process continues, which forms lesions called antherosclerotic plaques
- If plaque ruptures, blood clotting happens and a blood clot (thrombus) forms
- Thrombus can be dislodged and travel through body, becoming an embolus and blocking other arterioles.
What are the consequences of coronary occlusion?
Can lead to coronary heart disease - where clots slow blood flow to heart
Can cause myocardial infarction where blood tissue dies due to lack of oxygen
What is interstitial fluid?
Fluid formed from the blood plasma pushed through capillary walls to surrounding tissue - found between cells
What does interstitial fluid contain?
Hormones, nutrients, solutes e.g. ions, water
What is the function of interstitial fluid?
Bathes cells and allows movement of materials so they can be exchanged between blood and cells
Which substances do NOT move out of capillaries into the interstitial fluid?
Red blood cells, plasma proteins, platelets - TOO LARGE
What affects the amount of interstitial fluid pushed out by capillaries?
Hydrostatic pressure - high at arterial end, so lots of fluid pushed out. Low at venous end so fluid drawn into capillaries.
Where does excess interstitial fluid go?
90% drains back into capillaries, other 10% goes into lymphatic capillaries
Features of lymphatic capillaries
Thin and permeable walls - made of a single layer of endothelial cells which contain small gaps between cells
Have valves to prevent backflow
Blood carried at low pressures so movement of lymph is reliant on surrounding skeletal muscle
Where does lymph in lymphatic capillaries go?
Drains into lymphatic ducts which transport it to lymph nodes
What happens at lymph nodes?
A type of lymphocyte called Dendritic cells sample the lymph for pathogens. They then trap and destroy harmful substances such as toxins or foreign particles.
What happens to lymph after it has been filtered through the lymph nodes?
Lymph is returned to circulatory system. Then the waste products / destroyed bacteria from lymph nodes are removed by liver or kidneys
What are the two types of circulatory systems?
Pulmonary circulation - Blood pumped from heart to lungs, then returned to heart
Systemic circulation - Blood pumped from heart to rest of organism back to heart
Advantages of double circulatory system
Physical separation of oxygenated and deoxygenated blood maintains conc. Gs - maximises material transport - high metabolic demands can be met.
Allows low pressure to lungs and high pressure to rest of body
Why do mammals have higher metabolic demands than fish?
Fish are cold blooded so do not have to use as much energy to maintain homeostasis.
Purposes of locomotion
Foraging for food, Migration, Finding a mate, Escaping danger
What are skeletons
Rigid framework that functions to provide support and protection for organs
Endo vs Exoskeletons
Endo - Inside the body consisting of numerous bones
Exo - Outside the body consisting of different segements joined together
What are levers and anchors in the body?
Anchors - joints
Levers - Bones
