Physiology Quiz #1

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

1. 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

1. uniporters, 2. cotransporters

Uniporters…

transport a single solute at one time

Cotransporters…

2 types, transport multiple solutes each time

2 types of cotransporters

1. 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