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4 Main Phylogenetic tree groups
mammals, amphibians, reptiles, fish
Penetrating Solutes
can diffuse quickly accross cell membranes
Penetrating solutes characteristic
small, non-polar/hydrophobic solutes
Non-penetrating solutes
require protein mediated transport to go across the cell membrane
Non-penetrating solutes characteristics
large, polar/charged
Protein mediated transport
proteins allow or disallow solutes through the membrane
Channel proteins (Protein Mediated Transport) 2 main types
1.Porins (non-gated) 2. Gated channels
Porins are…
always open for a specific solute, passive transport, no binding and release
Gated channels are…
closed to start and open with a specific stimulus
3 Types of Gated Channel proteins
Voltage gated, 2. ligan/chemically gated, 3. Physically gated
Voltage gated channel is…
a protein that is sensitive to voltage
a ligan/chemically gated channel is…
where a certain signaling molecule will bind to the channel and cause a conformational change to open the channel
Physicall gated channels are…
channels that open when they are stretched or moved (ex. cilia in ears)
Carrier Proteins must…
bind to any solute they are transporting, conformational change occurs to move the solute
2 types of Carrier proteins
uniporters, 2. cotransporters
Uniporters…
transport a single solute at one time
Cotransporters…
2 types, transport multiple solutes each time
2 types of cotransporters
symporters, 2. antiporters
Symporters…
move all solutes in the same direction
antiporters…
move solutes in opposite directions
carrier proteins use…
active transport
active transport requires…
energy from ATP or GTP to power movement/transport of solutes AGAINST their gradient
Gradient
the difference in some sort of measurment between two points (things want to move down their gradient)
Diffusion
the passive movement of things down their gradient, very fast over small distances and high temperatures
Net flux
rate measurment on how much “flex” or flow happens in a period of time
higher gradient=
higher net flux
higher area=
higher net flux
Ficks law
net flux= gradient * area to move * ease of movement
solute
what is disolved by the solvent
solvent
what disolves the solute
solution
both together forms a solution
osmolarity
total solute concentration of the solution, can also be used to tell us abt the water in the solution
Hypoosmotic
lower osmolarity of solution, lower solute in solution than in the cell
Hyperosmotic
higher osmolarity of a solution, higher solute in solution than in the cell
Isoosmotic
same osmolarity of a solution
Tonicity
the ability of a surrounding solution to cause a cell to gain or lose water through osmosis
Hypotonic
when a cell swells in a solution, the solution is hypotonic
Hypertonic
if a cell shrinks in a solution, then the solution is hypertonic
Isotonic
there is no net movement of water, no change in cell volume
water moves toward…
the higher concentration of non-penetrating solutes (we do not look at penetrating solutes because they will equally spread themselves out)
Direct cell to cell signaling
signaling molecule does not enter teh extracellular fluid, moves through gap junction
Indirect cell signaling
signaling molecule enter extracellular fluid, attaches to target cell on a receptor
receptors are specific to…
one or a few chemical signals
In the endocrine system hormones…
are used as signaling molecules
Hormones come from…
glands, endocrrine tissues or cells
Hormones are transported through…
blood (indirect signaling)
Hormones work well in…
low concentrations
Positive feedback loops…
sense a physiological variable and push it further away from its set point
negative feedback loops…
sense a physiological variable and bring it back to its set point
A positive and negative feedback loop make...
antagonist regulation
Synergy
the combined response of two things is greater than the sum of their individual parts
Feedback loops response sometimes…
is a synergist response or additive response
Trophic hormones
any hormone that directly affects the release of another hormone
what does the hypothalamus do?
regulates the pituitary hormones
Hypothalamus to anterior pituitary trophic hormone chain
Hypothalamus > CRH(corticotropin releasing hormone) via portal vein> Connects to anterior pituitary > releases ACTH (adrenocorticotropic hormone) *via blood > cells in adrenal cortex > release of cortisol > creates 2 negative feedback loops inhibiting ACTH, and CRH
Cortisol affects…
stress hormone, increases heart rate, blood glucose
Posterior pituitary releases…
oxytocin and vasopressin
Posterior pituitary (difference to anterior)
more direct regulation from hypothalamus
no portal vein
no trophic hormones
Posterior pituitary hormone release process
neurons in Hypothalamus axons’ project into posterior pituitary, oxytocin and vasopressin are released into the blood
Membrane Potential
a charge difference across the membrane
Equilibrium Potential
the MP at which the electrical gradient exactly counteracts the concentration gradient (balance)
Neurons are coded as…
changes in membrane potential
