Chapter 6- Communication, Integration, and Homeostasis

electrical signaling

changes in membrane potential

chemical signaling

secretion of chemicals into ECF

homeostasis

Maintenance of internal conditions within a range of
values for physical and chemical parameters

gap junctions

junctions that form protein channels between adjacent cells

secreted molecules

Act on receptors in target cells or tissues

autocrine

secreted molecules that act on receptors on the same cell

paracrine

secreted molecules that act on receptors on nearby cells

Hormones

Chemicals secreted by endocrine cells. They travel in blood and act on distance target tissues

neurohormones

Secreted by neurons and travel through bloodstream

neurotransmitters

secreted by neurons and trigger response by diffusing across gap and binding to target cell

neuromodulators

secreted by neurons for autocrine or paracrine signaling

ligand binding

what opens and closes ion channels?

it activates a second messenger in the cell

What happens when a G-protein is activated?

G-protein coupled receptors

membrane-spanning proteins linked to “G Protein”

*fill in later

Adenylyl cyclase steps

*fill in later

phospholipase C steps

paracrine

what mode of secretion do gasses typically act in?

nitric oxide

◦ Vasodilator and neurotransmitter
◦ Increases diameter of blood vessels
◦ Present in neurons
◦ Made by synthase

carbon monoxide

Made by some cells to target smooth muscle

hydrogen sulfide

Recently discovered to relax blood vessels

endocrine

 release hormones
 Transported in the blood
 can potentially target any cell

neural

 electrical signals that are more specific,
 faster
 shorter duration

sensors

nervous system receptors

central receptors

sensors in the CNS

peripheral receptors

sensors outside of the CNS typically close to the surface of the body/skin

tonic control

Set point can be altered in both directions and control is always active

blood vessel diameter

example of tonic control

antagonistic control

Sympathetic and parasympathetic divisions

-one increases rate and the other decreases it

heart beating

example of antagonistic control

Sympathetic, parasympathetic

in antagonistic control….

◦ _____________ system increases rate
◦ _____________ system decreases the rate

stimulus

change in a physiological parameter

sensor

recognizes stimulus and sends afferent signal

integration center

receives signal for sensor and compares input to set point

output

efferent signal generated

target or effector

carries out response

contact dependent signals

signals that require interaction between membrane molecules on 2 cells

ligand, receptor, 2nd messenger, response

path of a signal transduction pathway

protein kinases, amplifier enzynmes

targets of signal transduction pathways