BIPN 100 Lecture #1 Terms - Emergent Properties in Physiology and Introduction to Neurons

Homeostasis

Maintenance of stable internal environment conditions; dynamic steady state

What are the internal environments of Homeostasis?

Intracellular Fluid (ICF)

Extracellular Fluid (ECF) - also includes interstitial fluid (ISF), fluid between cells

What are the different steps of the Homeostatic Reflex Loop?

1. Stimulus— change in environment

2. Sensor— specialized receptor, monitors regulated variable

3. Integrating Center— the control

4. Effector— caries out response

5. Response/Compensatory Mechanism— response that returns homeostasis

Negative Feedback Control

Homeostatic, keeps system at/near setpoint by opposing or removing signals (ex. blood pressure)

Positive Feedback Control

response reinforces stimulus, further moving stimulus away from normal value until event (ex. uterine contractions when pregnant)

Law of Mass Balance

amount of a substance in the body remains constant

• any gain must be offset by an equal loss

Name some of the parts of a neuron.

• Plasma membrane

• Dendrites

• Soma/Cell Body

• Axon Hillock

• Axon

• Axon Terminal

• Synapse

Plasma Membrane

consists of both lipids and proteins where receptors and channels allow specific molecules to pass through

Dendrites

thin, branched processes that RECEIVES incoming info from other neurons

Soma/Cell Body

the spherical part of the neuron that contains the nucleus and organelles necessary for cell function

function: integrates inputs from dendrites

Axon

long extension from the soma to transmit outgoing electrical signals

function: axon transport moves vesicles down/up axon

Axon Terminal

enlarged button-shaped that is the end of an axon

function: stores and secretes chemical messengers; electrical signal to release

Synapse

junction between axon terminal of presynaptic neuron and postsynaptic target cell

Ion Channels

membrane proteins w/ selective permeability for particular ions

Sodium-Potassium Pump

Na+-K+-ATPase

carrier membrane protein, maintains resting membrane potential

Central Nervous System (CNS)

brain and spinal cord

Peripheral Nervous System

nerves and ganglia

What are 3 different types of neurons?

Afferent Neurons

Interneurons

Efferent Neurons

Afferent Neurons

PNS, sends sensory information towards the CNS

function: receives sensory info

Interneurons

CNS, integrate inputs and communicates w/ other interneurons and efferent neurons

function: integrate sensory info to produce response

Efferent Neurons

carry info to effector organs (muscle, glands, etc) away from CNS

function: send motor/autonomic messages