Mass Transport + Gas Exchange In Humans Flashcards
Explain how the highest blood pressure produced in the left ventricle
Stronger contractions as it has thicker muscular wall
Explain the role of the heart in the formation of tissue fluid
Ventricles contract forming high hydrostatic pressure
Which forces water out of the capillaries
Describe and explain adaptation of alevolar epithelium
• 1-cell thick, which reduces the diffusion distance , so a increases the rate of diffusion
Explain how the constant flow of blood aids gas exchange in the lungs
• maintaining the concentration gradient
• By replacing oxygenated blood with deoxygenated blood
Explain and describe how the elastic tissue in the wall helps to even out the pressure of blood flowing
through the artery or during exhalation
stretches as a result of high pressure/surge of blood;
then recoils
Which helps to push air out
Apart from lung cancer and other cancers, name 2 other diseases whose risk factors are increased by smoking
•Heart disease
•Diabetes
Describe and explain 2 adaptations of alveoli that enable rapid gas exchange
• Large number of alveoli- so that there is an increase in surface area
• Alveolar epithelium is only one cell thick- so there is a reduces diffusion distance, increasing the rate of diffusion
• A large network of capillaries- so that there is a short diffusion distance
Describe the pathway taken by a CO2 molecule from the blood to outside the air
•Across the endothelial wall of the capillary
• across the alveolar epithelium into the alveolar space
• It then travels up the bronchioles and up the bronchi
• Into the trachea and out the mouth/nose
An oxygen concentration gradient is maintained between the alveoli and the lung capillaries. Describe and explain how this is maintained
• Ventilation brings in air with a high Oxygen concentration
• Circulation removes blood with a high oxygen concentration
Explain how the volume of the thorax increases
• external intercostal muscles contract
• diaphragm contracts, moving the rib cage up
How are red blood cells adapted to carry oxygen?
- concave shape gives a big surface area for absorbing oxygen. it also helps them pass smoothly through capillaries to reach body cells
- packed with haemoglobin which absorbs oxygen
- they have no nucleus to leave even more room for haemoglobin
Explain how the stain allows you to distinguish between white and red blood cells
White blood cells have a nucleus that stains whereas red blood cells do not
Suggest how a blockage in the lymphatic system could cause lymphoedema
Excess tissue builds up
Explain how cardiac output could stay the same even when their resting heart rate had decreases
Cardiac output= stroke volume x heart rate
Stroke volume increases
Units dm3min-1
Effect of flow of blood between aorta and pulmonary artery could cause death
Less oxygenated blood flows through aorta
Less oxygen delivered to cells
Not enough oxygen for aerobic respiration
Tissue doesn’t grow properly
Explain four ways in which the structure of the aorta is related to its function
Elastic tissue stretches when ventricles contract to prevent pressure rising to high when blood flows past
Recoils to maintain pressure
Has Muscle for contraction
Thick wall to withstand pressure
Smooth endothelium reduces friction
Aortic valve prevents back flow of blood
Species B more active then A. How will the graph show Haemoglobin of B shows greater activity
Curve to the right so LOWER affinity
Haemoglobin dissociates more readily
More oxygen delivered to cells
For faster respiration
Explain how an arteriole can reduce the blood flow into capillaries
Muscle contracts
Constricts arteriole
*arteriole short small diamater causes increase in friction decrease in blood pressure
Give 2 safety precautions that should be followed when dissecting a heart
Use a sharp scalpel
Cut away from the body
Wash hands
Explain how atrioventricular valve maintains a unidirectional flow of blood
Pressure in left atrium higher than in ventricle causing valve to open
Pressure in left ventricle higher than in atrium causing valve to close
Deacribe how tissue fluid is formed and how it is returned
High hydrostatic pressure
Forces water out
Large proteins remain in capillary
Return
Lower water potential in capillary due to plasma proteins
Water enters the capillary by osmosis
Smokers have loss in elastic tissue
Coronary arteries
Branch off the aorta and supply heart muscle w blood
Wat is the wall of the heart made of
Cardiac muscle
Cardiac cycle
Atria systole
Ventricular systole
Diastole
Risk factors in CHD
High cholesterol diet , high lipid diet, lack of exercise, smoking
Leads to
High blood pressure increase in cholesterol levels in the blood
Leads to
Damage to endothelium wall snd increase in lipid uptake
Liver blood vessels
Hepatic artery
Hepatic vein
Hepatic portal vein - takes blood from the intestines to the liver
Kidney vessels
Renal artery+ vein
What is Mass flow
The bulk movement of liquids and gasses due to a pressure differencd
Explain how oxygen in a red blood cell is made available for respiration in active tissues
Increase in Co2 due to increased respiration
Increased dissociation of O2 from hameoglobin
Low PO2 in tissues
Oxygen diffuses from rbc to tissues
Describe how HB normally loads in O2 and unloads in tissue cell
Oxygen combines to produce oxyhaemoglobin
Each haemoglobin may transport 4 O2 molecules
High PO2 in lungs
HB fully saturated
Presence of CO2 displaces curve to right
Causes more O2 to unload as increase in acidity
Low PO2 in respiring tissues
Describe structure of artery and vein
Explain features which help to carry out their functions
Artery has thick wall
Allowing it to withstand high pressure
Whereas vein has thin wall
As does not need to withstand high pressure
Both have epithelium (1 cell thick)
Consisting of squamous cells
Reduces friction with blood
Elastic tissue stretches and recoils
Maintaining high pressure on blood
Veins have valves
Which prevent back-flow of blood
Explain structures of walls arteries and arterioles
Elastic tissue stretches under pressure
Recoils
Evens out pressure
Muscle contracts
Constricts the vessel
Changes pressure
Smooth epithelium
Reduces friction
Explain why thickness of aorta wall changes all the time during cardiac cycle
Aorta wall stretches
Because pressure in ventricle increases
Aorta wall recoils
Because ventricle relaxes
Maintains smooth flow/pressure
Describe and explain how lungs are adapted to allow rapid exchange of oxygen between air in alveoli and blood in capillaries
Many alveoli provide large SA
Many capillaries provide large SA
So fast diffusion
Alveoli one cell thick
Squamous epithelium
Short diffusion pathway
Ventilation+ circulation maintains a diffusion/conc gradient
Describe how heart muscle and the valves maintain one way flow of blood from LA to aorta
Atrium has higher pressure in ventricle due to filling of blood
Av valve opens
Ventricles have higher pressure in atrium
Av valve closes
Ventricle higher pressure in aorta
Semi lunar valve opens
Higher pressure in aorta
Semi lunar valve closes
Muscle contracting increase in pressure
Arteriole compared to the artery
Smaller diameter compared to artery so greater friction decreasing blood pressure
Thinner elastic layer- lower blood pressure
Thicker muscle layer-reduces blood flow into the organ ( to increase O2 delivery to respiring muscle cels for respiration)
Describe 2 precautions that student should follow when clearing away after dissection
Wash hands
Disinfect instruments
Myoglobin dissociation curve
Higher affinity for O2 than Hb
Allows aerobic respiration at lowe PO2
Delays anaerobic respiration
Myoglobin dissociation curve
Higher affinity to oxygen at lower PO2
Allows aerobic respiration to take place at lower PO2
Delays anaerobic respiration
Blood vessel thar carries blood at lowest blood pressure
Vena cava
Explain how water from tissue fluid returned to circulatory system
Plasma proteins remain
Creates water potential gradient
Water moves to blood by osmosis
Returns to lymphatic system
