Levels of Organisation Flashcards
Levels of Organisation
Chemical - Cellular - Tissue - Organ - Organ System
What is Homeostasis?
Maintaining a stable internal environment, and must be maintained in order to survive.
- regulation is adjustments in physiological systems
How is Homeostasis regulated?
“Receptor” (detects change in stimulus)
“Integration Centre” (receives & processes info from receptor)
“Effector” (increases or decreases stimulus)
What is Positive feedback?
Initial stimulus causes response that increases stimulus.
e.g. blood clotting, child birth, labour.
What is Negative feedback?
- Variation in homeostasis will trigger an automatic response that corrects the situation
- Ignores minor variations and maintain normal range
- Most homeostatic mechanisms in body involve negative feedback
How is homeostasis maintained?
Through combined actions of many different cells.
What do cells do?
- Maintains homeostasis through combined actions o many cells
- Maintain anatomical structures
- Smallest structural unit of life
What is surround the cell?
- Extracellular substance (watery fluid)
- Cell membrane that separates cytoplasm (intracellular from extracellular fluid)
- Cytoplasm surrounds nucleus
What 2 liquids does the cytoplasm contain?
Cytosol & organelles
What are the functions of the Cell Membrane?
- Physical barrier (separates inside of cell from extracellular fluid)
- Regulates exchange in environment (controls entry and exit of ions & nutrients, eliminates waste and releases cellular secretions)
- Sensitivity (first part of cell to be affected by ECF and contains receptors)
- Structural support
What fluids are the Cell Membrane made up of?
2 LAYERS: Hydrophilic (head - water loving)
Hydrophobic (tail - water hating)
What does the tail act as?
A selective barrier
What is in the Phospholipid bilayer made up of?
Cholesterol, proteins, carbohydrates
What are the 2 membrane proteins?
- Integral proteins (entire width of membrane - act as channels)
- Peripheral proteins (attach to integral proteins)
What do the Membrane Carbohydrates do?
- Cell lubricants
- Glycocalyx (specific biological marker)
- Helps to recognize bacteria and viruses
What are the types of permeability?
- Impermeable = Nothing can leave
- Permeability = Cross membrane freely
- Selectively Permeable = Some can or can’t freely
Does Active Transport require energy?
Yes, in the form of ATP
Does Passive Transport require energy?
No
What is involved in PASSIVE Cellular Transport?
- Diffusion
- Osmosis
- Osmotic Pressure
- Osmotic Flow
- Facilitated Diffusion
What is Diffusion?
Substances through High to Low concentrations WITHOUT energy
What is Osmosis?
The diffusion of water across cellular membranes
- the Higher the solute, the Lower the water conc.
- Water flows across membrane towards solution containing higher solute conc.
- Occurs across a selective permeable membrane.
What is Osmotic Pressure?
The force of the water going through depends of what is in the most highly conc. area
What is Osmotic Flow? (types of flow)
ISOtonic solution = balanced/equilibrium
HYPOtonic solution = water will flow into cell
HYPERtonic solution = water will flow out of cell
What is Facilitated Diffusion?
Substances moved by binding to carrier molecules
What is Active Transport?
- Uses ATP to move molecules & ions across membrane
- Not dependent on conc. gradient
- Occurs when substances that are too large to pass through pores
- ATP needs to bind to protein in order for K+ & Na + to move in and out of cell
- SODIUM-POTASSIUM PUMP (helps with muscle contraction)
