Multicellularity & Homeostasis
What is one of the possible downsides/drawbacks to cellular specialization?
Cells can lose the ability to live and function independently
Ectotherm, Endotherm, Heterotherm
Which group do MOST animals fit into?
Ectotherm: temp determined by external sources of heat (MOST animals)
Endotherm: temp determined by metabolic heat production & active heat loss
Heterotherm: can behave as either of the above
Endo: secrete products into bloodstream
Exo: secrete products into ductal system that goes to epithelial (skin) surface
Explain the difference between neurons & glial cells.
Neurons - cells that send/receive electrical & chemical signals
Glial cells - support neuron function
The central nervous system consists of what parts?
Brain & Spinal cord
Tissue - specialized cells
Organ - multiple tissues functioning together
Organ System - multiple organs working together
What is the significance of the Na/K pump in thermoregulation of endotherms?
"leakiness" of the pump in endotherms allows for more use of energy (to maintain the gradients)
What is the definition of a hormone?
Why are paracrine and autocrine signals NOT hormones?
def: chemical signal released by one type of cell to influence other cells at a distance
Paracrine - only affects nearby cells
Autocrine - cells only affects itself
What are the 3 functional regions of a neuron and what neuron parts correspond to the regions?
1) Receptive - dendrites/body
2) Conducting - axon
3) Secretory - axon terminal
Any of the following:
-Skull
-Meninges
-CSF (cerebrospinal fluid)
- extracellular matrix
-cell junctions
-cells that communicate
-specialized cells
What is brown fat and what type of regulation is it an example of?
Example of heat production regulation - produces heat in cold temperatures
Where would you expect to find the receptors of hydrophilic hormones? Hydrophobic hormones?
Hydrophilic: receptor on the membrane
Hydrophobic: receptors within cytoplasm or nucleus
What is the function of the myelin sheath?
neuroglial cells that wrap around an axon and provide layers of insulation
insulation = increased speed of action potential
Grey - dendrites and cell bodies
Why are animals multicellular and what does being multicellular allow them to do better?
Why: to allow for larger size, cells can specialize
Better: survival in more conditions, predation, increased exchange with environment
Explain the concept of countercurrent exchange and give 1-2 examples of it in animals.
"colder" blood near body surface is warmed by "warm" blood that passes by it as it leaves the core
Ex: wolves, birds, fish
A hormone called X is derived from cholesterol and not encoded in the genome. X is also hydrophobic and requires transporters to be carried in the blood. What type of hormone is X?
Steroid Hormone
During repolarization which channels open and which channels close?
Na channels close
K channels open
As the result of a brain injury, a patient is displaying changes in their personality and behavior as well as trouble with understanding normal vocabulary words. Which lobe(s) of the brain was/were most likely affected by this injury?
Frontal Lobe & Temporal Lobe
Positive - increases the change
Explain the importance of vasodilation and vasoconstriction in thermoregulation.
Vasodilation = blood vessels dilate
- increase blood flow, more heat loss
Vasoconstriction = blood vessels constrict
- decrease blood flow, conserves heat
How do the nervous system & endocrine system differ in the following:
1) Location of signal
2) Target
3) Response
1) N: neurotransmitter, E: hormone
2) N: specific cells, E: any cell with receptor
3) N: rapid response, E: delayed response
Contrast ligand-gated channels and voltage-gated channels.
Ligand: open in response to binding of chemical/ligand to receptor
Voltage: open in response to changes in voltage across membrane
What would you expect the effect of an injury that damaged Broca's & Wernicke's areas to be?
Broca: difficulty making speech sounds
Wernicke: difficulty understanding words