Week #3 (1/21 – 1/24)Warm Up – Tues, 1/21:- Review of Intro to NS

Pick up:Action Potential notesSyn. Pot. & NT Review wkst

Have out:???

Agenda:1. Begin Action Potential notes

Anatomy Fun Fact:Neurons, which are the largest cells in the human body, do not undergo the process of mitosis. - Why is this important to know?

Homework:1. Reflex Lab

Abstract (5I) – Fri, 1/24

2. Syn. Pot. & NT Review wkst – Fri, 1/24

3. Action Potential Quiz – Fri, 1/24

Warm-up: Intro to NS Review

• What organs are included in the CNS?

• What are the 3 main parts of a neuron?

• What is the function of the dendrites? Cell body? Axon?

• What does SNS stand for & what kind of tissue does it control?

• Are reflexes controlled by the SNS monosynaptic or polysynaptic?

• Let’s play a game of “Telephone”! I’ll start by giving a message to….

• In a Reflex Arc, what role are you & I playing (hint: it’s a cell)?▫ Neurons

• In anatomy, what is the space between each communicator called?▫ Synaptic cleft or synapse

• Was the message sent successfully?▫ If not, why not?

How many parts How many parts were there to communicating were there to communicating the message?the message?1st: the person had to receive it (listening) – role of the dendrites of a neuron

2nd: the listener had to process the information (understanding the context of the words) – role of the soma/cell body

3rd: the person had to send the message (speaking/ sending it to the next person) – role of the axon

• Information from one neuron flows to another neuron across a synapse/synaptic cleft…▫ a small gap separating

neurons that consists of: a presynaptic ending

(axon terminals) that contains neurotransmitters (NTs), mitochondria & other organelles,

a postsynaptic ending (dendrites) that contains receptor sites for NTs &

a synaptic cleft or space between the presynaptic & postsynaptic endings.

BIOLOGY REVIEW: What is the process of Diffusion?

• When it comes to understanding how neurons communicate (Action Potential or Nerve Impulse), you must understand how the process of diffusion works!▫ Diffusion Animation▫ Particles move down their

concentration gradients (from high to low)

• Is it an active or passive form of transporting dissolves nutrients?▫ Passive – NO ATP REQUIRED!

• Also known as “Nerve Impulses”

• Self-regenerating wave of electrochemical activity that allows neurons to carry a signal over a distance (“game of telephone”)

• Pulse-like waves of voltage that travel along several types of cell membranes

• Analogy – assume students are POSITIVELY-CHARGED Na & K IONS!

• Initiation/Resting Stage:▫ Outside the classrooms (neuron) vs. inside classrooms (neuron)▫ At 7:20 a.m., more students are arriving to school than are

sitting in a “0” hr class▫ So the inside of the classrooms (neurons) have a “negative”

polarity.

• Initiation/Resting Stage:▫ Some K+ channels are open: K+ diffusion occurring (out)

▫ Initiated by stimulus above a certain intensity or threshold (~-70mV – resting potential)

▫ Could be a pin prick, light, heat, sound or an electrical disturbance in another part of the neuron (“telephone call”)

▫ Electrical signal rises from changes in permeability of the neuron’s axon membranes to specific ions (Na+ & K+)

• Analogy – assume students are POSITIVELY-CHARGED Na & K IONS!

Depolarization (Rising Phase):▫ Outside the classrooms vs. inside classrooms▫ First bell rings & students move from the

halls into the classrooms▫ This gives the inside of the classroom

(neuron) a more “positive” polarity.

Depolarization (Rising Phase) K+ Channel gates are closed Stimulus causes gate in the Na+ Channel to open High concentration of Na+ outside, Na+ diffuses into

neuron Electrical potential changes to ~ +40 mV

• Analogy – assume students are POSITIVELY-CHARGED Na & K IONS!

Repolarization (Falling Phase):▫ Outside the classrooms vs. inside classrooms

▫ Dismissal bell rings & students leave the classroom & enter the halls

▫ This gives the inside of the classroom (neuron) a “negative” polarity again.

Repolarization (Falling Phase) Depolarization causes K+ Channel gates to immediately

open & Na+ Channels close K+ diffuses out of neuron Reestablishment of initial electrical potential

of ~-60 mV

Refractory Period (Recovery Phase) Na+ & K+ Channels cannot be opened by a

stimulus Na+/K+ Pump actively (ATP required) pumps

Na+ out of & K+ into neuron (against/up their concentration gradients) Reestablishment of ion distribution of

resting neuron This AP acts as stimulus to neighboring proteins

within neuron membrane & initiates AP in another part of neuron Wave of APs travel from dendrites to axon

terminals At axon terminal, electrical impulse is converted

to a chemical signal (neurotransmitter)

Week #3 (1/21 – 1/24)Warm Up – Wed, 1/22 & Thurs, 1/23: - Analyzing the Change in Impulse

Have out:Reflex Lab handoutPick up:Analyzing the Change in Impulse wkst

Agenda:1. Getting the Message across the

Synapse2. Neuron/Action Potential Model-building

OR Pushing the Limits: Brain Power

Anatomy Fun Fact: The sciatic nerve is the largest in the human body, about as thick as a pencil (~0.78 in). It is composed of nerve fibers (collection of neurons) that run from the spinal cord to & down the back of each leg.

Homework:1. Reflex Lab

Abstract (5I) – Fri, 1/24

2. Syn. Pot. & NT Review wkst – Fri, 1/24

3. Action Potential Quiz – Fri, 1/24

Action Potential animation

• Getting the message across (the synapse)?▫ At axon terminal, chemical

signal (NT) crosses synapse between adjacent neurons Starts AP on this neuron

▫ This activates Ca2+ channel to open Ca2+ diffuses into neuron Causes NT vesicles to move to end & fuse with cell membrane Through exocytosis, NTs are released into synapse

▫ NTs diffuse across synapse & bind to NT receptors on another neuron Causes Na+ channels to open & AP is initiated in next neuron

Let’s Review… How do neurons communicate?

• Action potential animation (~3 mins)• What is another name for the nerve impulse that travels

from the cell body down the axon to the axon terminal?

• What happens in the Rising Phase/ Depolarization? ▫ Falling Phase/Repolarization? ▫ Recovery Phase/Refractory Phase?

• Once the AP has reached the axon terminal, what ion entering the neuron instigates the movement of synaptic vesicles to the cell membrane?

• What do the vesicles release into the synapse?

Action Potential/Neuron Model• You will be divided into 4 groups to create 4 different

Neuron models!

• You will be presented with various materials you may choose to use for your model.

• Each group will develop a model of a neuron, including:▫ Dendrites - Cell body (soma)▫ Axon - Synaptic terminal (axon terminal)

• Your neuron will also demonstrate the transmission of:▫ Action potential - Neurotransmitters

• You will be demonstrating your model to the class on Fri, 1/24 (before Quiz on Action Potentials)!

• Return any unused materials to where you found them!

• Do NOT waste materials…all materials were bought by me!

Action Potential/Neuron Model•Each model of a neuron has to include:

▫Dendrites▫Cell body (soma)▫Axon▫Synaptic terminal (axon terminal)

•Your neuron will also demonstrate the transmission of:▫Action potential▫Neurotransmitters

•Title your paper “Pushing the Limits: Brain Power Facts” paper & have out a pen/pencil.▫Identify & explain at least 5 new concepts/ideas/facts you learn about the human brain/mind from the video.Add these to your paper!

Pushing the Limits – Brain Power

Week #3 (1/21 – 1/24)Warm Up – Fri, 1/24: - Neuron Models Demo/Syn. Pot. & NT Review wkst

Turn in:Reflex Lab Abstract (5I) Have out:Neuron models?Syn. Pot. & NT Review wkst

Agenda:1. Action Potential Quiz2. Ch. 14 Tour (Brain)

Anatomy Fun Fact: An action potential (nerve impulse) is very quick & has the ability of transmitting impulses at the speed of 100 meters/second. The speed of message transmission to the brain can be as high as 180 mph.

Homework:1. Ch. 14 Tour –

Wed, 1/29 & Thurs, 1/30