Exchange Systems Flashcards
What are the three methods of transport in the human body?
- Diffusion - the passive movement of particles form a high concentration to a low concentration until equilibrium through a partially permeable membrane. Follows the concentration gradient. Liquids and gases.
- Osmosis - the passive net movement of water particles from a dilute to a less dilution concentration through a partially permeable membrane until equilibrium. Follows conc. gradient. Water only.
- Active transport - the active movement of particles from a region of low concentration to a region of higher concentration through a partially permeable membrane. Does not aim for equilibrium. Goes against conc gradient. Mineral ions and glucose.
What are the five main organ systems of the body?
- Circulatory
- Nervous
- Digestive
- Excretory
- Respiratory
Explain the importance of a small surface area to volume ratio.
Large organisms have a small surface area to internal volume ratio b/c diffusion only through the external surface area would be too slow to deal with their requirements.
How are alveoli adapted to ensure efficient gaseous exchange? (3)
- Elastic recoil and expansion - after inhaling both the surface area and the volume increase, allowing more oxygen to be taken in.
- Receive a very rich blood supply (fast blood flow) - allows oxygen to be released into the bloodstream and the absorption of carbon dioxide into the alveoli to be released as waste.
- Thin cell membrane - ensures a short diffusion distance and therefore efficient gaseous exchange.
How are villi adapted to their function?
Finger-like protrusions in small intestine - increases surface area to volume ratio for more efficient active transport
Name and describe the function of the organelles of an animal cell.
- Partially permeable cell membrane - allows particular sized substances in and out of the cell.
- Nucleus - contains genetic material of the cell, which codes for its functions. Site of transcription.
- Ribosome - location of protein synthesis.
- Cytoplasm - Site of anaerobic respiration and key metabolic reactions.
- Mitochondria - sight of aerobic respiration.
Describe the process of hemolysis.
- Once a red blood cell is placed in a hypotonic solution (solution with low solute concentration), water molecules diffuse into the cell.
- This causes it to swell and burst (turgid), releasing substances like hemoglobin into the bloodstream.
Describe the process of crenation.
- When a red blood cell is placed in a hypertonic solution (solution with higher solute concentration), osmotic pressure causes the water molecules to diffuse out of the cell.
- This causes the cell to shrink or become crenated.
What happens when a red blood cell is placed in an isotonic solution?
- Isotonic solution = when the outside and inside concentrations are equal.
- There is no net movement of particles b/c equilibrium has already been achieved.
How can hemolysis and crenation be prevented?
Active transport can be controlled by carrier proteins in the partially permeable membrane.