Physiological Systems: signalling mechanisms

Question 1

Homeostasis

Answer 1

stable internal operating environment: keeps internal env. within limits

Question 2

Physiology

Answer 2

study of function (cells, tissues, etc)

Question 3

Physiological integration

Answer 3

body systems work together, all body systems under control/regulation of nervous system

Question 4

Intercellular signaling

Answer 4

between cells

Question 5

intracellular signaling

Answer 5

within cells

Question 6

Neurons

Answer 6

communicate via generation of chemical/electrical signals

Question 7

Chemical signals

Answer 7

communication at synapse; main chem signal: neurotransmitter

Question 8

Electrical sugnal

Answer 8

along plasma membrane of neuron; moving ions (movement of charge)

Question 9

Separation of charges

Answer 9

ions on either side of semi-permeable membrane: contributes to formation of membrane voltage (potential)

Question 10

Resting neuron

Answer 10

asymmetric distribution of ions across membrane (K+ more concentrated inside, others outside) –> resting membrane potential of ~ -70mV

Question 11

Ion transport

Answer 11

1. facilitated diffusion (molecules that cant cross membrane on own) 2. active transport (energy used to transport substances against concentration gradient)

Question 12

Ion Channels

Answer 12

ion transport path: selective for specific ions, gated

Question 13

Ligan-gated

Answer 13

chemically gated

Question 14

Voltage-gated

Answer 14

changes in membrane voltage gated

Question 15

mechanical-gated

Answer 15

changes in membrane stretch gated

Question 16

Concentration Gradient

Answer 16

influences direction of ion movement: generated by differences in concentration b/ two regions (high to low)

Question 17

Electrical gradient

Answer 17

influences direction of ion movement: asymmetric distribution of charge, attraction between opposites: driving force, time/access no electrical gradient

Question 18

Electrochemical gradients

Answer 18

determines net flux (in or out of cell) for ion : presence/direction/strength of electrical/concentration gradients

Question 19

Equilibrium potential

Answer 19

Potential across membrane that produces electrical force on ion EXACTLY oppoite to force of concentration gradient: BALANCES ionic concentration gradient

Question 20

Electrical signals generated in a neuron

Answer 20

neurotransmitters bind to receptors (ion channels to open) –> temp. change in membrane potential bc change in movement of ions across membrane

Question 21

Neurotransmitter binding to receptor changes

Answer 21

Depoloarization: membrane potential = less negative/less polarized: Excitatory Post-Synaptic Potential (EPSP)
Hyperpolarization: membrane potential gets more negative: Inhibitory “ “ (IPSP)

Question 22

Action Potential

Answer 22

if graded potentials depolarize membrane –> threshold voltage: neuron fires action potential

Question 23

Excitatory effect

Answer 23

brings membrane CLOSER to threshold to fire action potential

Question 24

Inhibitory effect

Answer 24

moves membrane AWAY from threshold

Question 25

Action Potential Phases

Answer 25

rising phase (upstroke), falling phase (repolarization), undershoot (hyperpolarization)