Animal Form & Function Flashcards
Complexity of Animals
Specialization of cells (tissue, nerve, stem, heart)
Transport system (e.g digestive system)
Control and coordination e.g hormonal and electrical
Does maintenance of homeostasis via negative feedback eg. Thermoregulation
What do small organisms have?
- Large surface area to volume ratio
- Short diffusion distance between environment and cells
Why is Surface area to volume ratio so important?
The rate of which resources can be obtained and used are dependent on it.
What increases SA?
Specialized branched or folded surfaces.
What do specialized transport systems and specialized fluids do?
Links each cell with the environment.
What is connective issue in animals?
- Connective tissue (most variable)
- loose elastic tissue
- hard supporting eg. Bones
- fluid connecting tissue eg. Blood
What are the types of tissue? Apart from connecting
Epithelial tissue
- tissues for exchange
Nervous tissue
- nerve cells to transmit electrical signals
Muscle cells
- produce cells that contract
Coordination and control what happens?
- Stimulus (from internal vs external environment)
- Growth reproduction
- Response is limited to specific cells (with specific receptors)
4.
Rapid behaviour (action potential) - Response (changes in membrane potential at target cells)
What is lipid solubility (not it’s not chemistry)
How easily the hormone that stimulates the target cell can pass through the membrane.
What are the steps to how a hormone functions?
- Endocrine cell is stored/released
- Transport in circulation
- Stimulates target cell
- Cellular response
What is negative feedback?
Maintains the constant level of hormones. Example: touching a hot stove
What is positive feedback?
Rare explosive events. Example: Childbirth (just keeps going till we’ll explosion)
What is the difference between the short term and long term response to stress?
Short term: Epinephrine (epi- pen) and Norepinephrine (increases alertness)
Long term: Cortisol (increases availability of oxygen and glucose to the brain)
What is the definition of action potential?
a rapid transient change in membrane potential
Know how to draw action potential
Switch to Knowt
Current vs Action potential
Current spreads In both directions.
Action potentials move in only one direction due to the refractory period.
How do Schwann cells and the myelin sheath allow for more rapid (saltatory) conductance of action potential?
Myelin sheath: insulates
Inward current during action potential is transmitted all the way due to Muslim sheath insulation.
Depolarizes membrane at the next node to regenerate a.p
Describe the transfer of information across neurons
DA.p. arriving at synapse depolarises pre-synaptic membrane
2 voltage- gated Ca
channels open, Ca influx synaptic vesicles move to and fuse with presynaptic membrane, release neurotransmitter into synaptic cleft 4) neurotransmitter binds to ligand-gated ion channels on post-synaptic membrane and change m.p.
Results in change in membrane potential of post-synaptic cell
What can the spinal cord do without instruction from the brain?
Act independently in simple nerve circuits eg. Reflexes
