Features Of Transport Systems Flashcards
What is the lymphatic system responsible for?
Draining tissue fluid, immune system function, transport of fats
The lymphatic system consists of vessels similar to capillaries that manage these tasks.
How is tissue fluid formed?
High hydrostatic pressure forces H2O and small molecules out of capillaries; large molecules remain in blood
This occurs at the arteriole end of a capillary.
Define tissue fluid.
Fluid that bathes the cells in the body’s tissues; blood plasma without plasma proteins
Tissue fluid is formed when blood plasma is forced through capillary walls.
How are capillaries adapted for the exchange of solutes?
- Thin walls
- Permeable wall
- Concentration gradient
These adaptations facilitate efficient solute exchange.
What are the three main types of fluid in the transport system?
- Blood plasma
- Tissue fluid
- Lymph
Each fluid serves distinct roles in the body.
What does tissue fluid contain?
Oxygen and nutrients
Tissue fluid provides necessary substances to cells.
What does lymph contain?
Carbon dioxide and waste materials
Lymph is formed from tissue fluid that has collected waste products.
What is ultrafiltration?
Process where small molecules are forced through capillary walls while larger molecules remain in blood
This process is crucial for the formation of tissue fluid.
How is tissue fluid returned to the circulatory system?
Via capillaries through osmosis and diffusion
At the venous end, hydrostatic pressure is lower and osmotic pressure is higher.
What happens at the venous end of a capillary?
- Hydrostatic pressure is lower
- Osmotic pressure is higher
- Water moves back into capillaries via osmosis
- Waste products diffuse into capillaries
This process aids in the recovery of tissue fluid.
What is the process by which tissue fluid is returned to the bloodstream?
Reabsorption
What term is used for the fluid that drains into lymphatic capillaries?
Lymph
Where does most lymph return to the venous system?
Thoracic duct
Into which vein does the thoracic duct empty lymph?
Left subclavian vein
What are the steps to determine whether tissue fluid will be formed or returned?
- Work out net effective HP (capillary HP - tissue fluid HP)
- Work out net effective SP (capillary SP - tissue fluid SP)
- Work out net effect of blood pressure (HP - SP)
- State where fluid will move
What are two ways lymph is moved through the lymphatic system?
- Contraction of surrounding muscles
- Valves in lymph vessels
How does skeletal muscle contraction aid in lymph movement?
Muscles bulge against vessels, squeezing lymph through
What is the role of valves in lymph vessels?
Prevent backflow of lymph
True or False: Lymph has a lower fat content compared to plasma.
False
What do phagocytes do in relation to lymph?
Engulf bacteria and foreign material
What is the composition difference between plasma, tissue fluid, and lymph?
Complete the table using HIGHER or LOWER as appropriate.
What components are typically found in lymph that are not found in plasma?
More fats from the digestive system and lymphocytes
What is the concentration of urea in blood plasma compared to tissue fluid and lymph?
Urea concentration is higher in blood plasma, tissue fluid, and lymph.
How does oxygen concentration differ in blood plasma, tissue fluid, and lymph?
Oxygen concentration is higher in blood plasma and lower in tissue fluid and lymph.
Where is carbon dioxide concentration the highest?
Carbon dioxide concentration is higher in tissue fluid and lymph but lower in blood plasma.
How does fat concentration vary between blood plasma, tissue fluid, and lymph?
Fat concentration is lower in blood plasma and tissue fluid but higher in lymph.
Where is glucose concentration the highest?
Glucose concentration is higher in blood plasma and tissue fluid but lower in lymph.
How does protein concentration compare across blood plasma, tissue fluid, and lymph?
Protein concentration is higher in blood plasma but lower in tissue fluid and lymph.
How does ion concentration vary across blood plasma, tissue fluid, and lymph?
Ion concentration is higher in blood plasma and tissue fluid but lower in lymph.
What does the oxygen dissociation curve illustrate?
It shows the relationship between the partial pressure of oxygen (pO₂) and the percentage saturation of hemoglobin with oxygen.
Why is the oxygen dissociation curve sigmoidal (S-shaped)?
Due to cooperative binding; as one molecule of oxygen binds to hemoglobin, its affinity for oxygen increases, making it easier for subsequent oxygen molecules to bind.
What is cooperative binding in hemoglobin?
It’s a process where the binding of one oxygen molecule to hemoglobin increases its affinity for additional oxygen molecules, resulting in the sigmoidal shape of the dissociation curve.
How does a rightward shift in the oxygen dissociation curve affect oxygen release?
A rightward shift indicates decreased hemoglobin affinity for oxygen, facilitating oxygen release to tissues.
What factors can cause the oxygen dissociation curve to shift to the right?
Increased carbon dioxide levels, higher acidity (lower pH), elevated temperatures, and higher concentrations of 2,3-bisphosphoglycerate (2,3-BPG).
What is the Bohr effect?
It’s the phenomenon where an increase in carbon dioxide concentration or a decrease in pH results in hemoglobin releasing oxygen more readily, causing a rightward shift in the dissociation curve.
How does fetal hemoglobin’s oxygen dissociation curve differ from adult hemoglobin’s?
Fetal hemoglobin has a higher affinity for oxygen, resulting in a leftward-shifted dissociation curve compared to adult hemoglobin.
What is the significance of the plateau phase in the oxygen dissociation curve?
The plateau indicates that hemoglobin remains highly saturated with oxygen even with slight decreases in pO₂, ensuring efficient oxygen transport under varying conditions.
How does 2,3-bisphosphoglycerate (2,3-BPG) influence the oxygen dissociation curve?
2,3-BPG binds to hemoglobin, decreasing its affinity for oxygen and promoting oxygen release to tissues, which shifts the curve to the right.
Why is the steep portion of the oxygen dissociation curve important?
The steep portion allows for significant oxygen unloading in tissues with small decreases in pO₂, facilitating efficient oxygen delivery where it’s most needed.
Why is hemoglobin’s oxygen affinity reduced at low pH?
At low pH (high acidity), hydrogen ions bind to hemoglobin, altering its shape and reducing its oxygen affinity, promoting oxygen release to tissues (Bohr effect).
How does exercise affect the oxygen dissociation curve?
During exercise, increased CO₂ production, higher temperatures, and lower pH cause a rightward shift in the curve, allowing more oxygen to be released to active tissues.
What is myoglobin, and how does its dissociation curve differ from hemoglobin?
Myoglobin is a protein in muscle cells with a higher oxygen affinity than hemoglobin. Its curve is not sigmoidal but hyperbolic, as it does not exhibit cooperative binding.
Why does fetal hemoglobin need a higher oxygen affinity than adult hemoglobin?
Fetal hemoglobin must extract oxygen from the mother’s blood across the placenta, so it has a higher affinity for oxygen to ensure sufficient uptake at low pO₂ levels.
How does altitude affect the oxygen dissociation curve?
At high altitudes, lower oxygen availability can trigger an increase in 2,3-BPG production, shifting the curve to the right and enhancing oxygen release to tissues.
What is the significance of hemoglobin saturation in the lungs and tissues?
In the lungs, high pO₂ allows hemoglobin to become fully saturated, while in tissues with lower pO₂, oxygen is readily released due to lower affinity.
How does carbon monoxide affect the oxygen dissociation curve?
Carbon monoxide binds to hemoglobin with a much higher affinity than oxygen, reducing oxygen transport capacity and shifting the curve to the left, impairing oxygen unloading.
How does temperature affect the oxygen dissociation curve?
Higher temperatures reduce hemoglobin’s oxygen affinity, shifting the curve to the right and enhancing oxygen release to active, warmer tissues.
Why is the oxygen dissociation curve important for respiration?
It ensures efficient oxygen loading in the lungs at high pO₂ and unloading in tissues where pO₂ is lower and oxygen demand is higher.
What physiological adaptations might occur in animals living at high altitudes?
Animals at high altitudes often have hemoglobin with a higher oxygen affinity (left-shifted curve) to load oxygen efficiently in low pO₂ environments.
How do pCO₂ levels affect oxygen unloading?
Higher pCO₂ levels lower blood pH (due to carbonic acid formation), which reduces hemoglobin’s oxygen affinity, promoting oxygen unloading in tissues (Bohr effect).
What role does the steep portion of the oxygen dissociation curve play during exercise?
The steep portion ensures a rapid and significant release of oxygen in tissues where pO₂ drops, such as during intense muscle activity
How does anemia affect the oxygen dissociation curve?
Anemia reduces the amount of hemoglobin available, but the shape of the dissociation curve remains the same; less oxygen is transported overall.
Why is the plateau phase of the curve advantageous at high altitudes?
The plateau ensures that hemoglobin remains almost fully saturated even when pO₂ in the atmosphere is lower, as it is at high altitudes.
