Brain+anatomy,+neuron+structure+and+function

Note: This includes ALL of the A.S. for the **Neurobiology and Behavior Unit** (Option E), PLUS the A.S. for the Nerves section of **Nerves, Hormones and Homeostasis** (Topic 6.5). These **WILL NOT** be covered in order in this unit. Each section will be updated with the corresponding A.S. as we go.

Pinky and the Brain Brain Song (You Tube video)

An interesting article on risk taking in teenagers:National Geographic article 'The New Science of the Teenage Brain" National Geographic interactive website (very informative website - play around on it for more info)


 * These are the specific A.S.that will be covered on the test for this section.**

The human brain Watch video "Brain Works" from University of Washington
 * 2/17/12**

Model brain diagrams

Interactive brain tutorial Turn in brain structures function definitions Finish model brain diagrams Intro to brain dissections
 * 2/21/12**

Begin brain dissections
 * 2/22/12**

Continue brain dissections
 * 2/23/12**

__Structure of a neuron__ (Dendrites, Soma, Axon, Axon terminal, Myelin sheath, Nodes of Ranvier)
 * 2/24/12 (Neuronal Structure and Function - part 1)**

__Types of neurons__

__Signaling within neurons is electrical__

__Myelin sheath increases conduction velocity__

//Neuron structure and function activity sheet (Read first page and answer questions 1-4 on back)//

HW: Read pages 251-258 and page 329 "Neurotransmitters and synapses" section in IB text. Read pages 939-951 through the section on "Synaptic Integration" in Raven and Johnson text.

**FYI: Neurons vs. Nerves**: (Nerves) - Bundles of neuronal processes enclosed in [|connective tissue] that carry signals to and from the [|central nervous system].
 * 2/27/12 (Neuronal Structure and Function - part 2)**



__Membrane potential drives electric current in neurons__

//Transmission of nerve impulses activity sheet (Read and answer questions 1-3 at bottom of page)//

Ion distribution inside and outside of neurons set up electrical gradient across the membrane. Concentrations of Na, Ca and Cl ions are higher on the outside than on the inside. Concentration of K ions is higher on the inside than outside. This results in an electrical gradient called the membrane potential. At rest, membrane potential is approximately -70 mV in most neurons.

Action potential animation Opening of Na ion channels leads to change in membrane potential and "depolarization" of the neuron. This leads to a sudden, large depolarization called an "action potential" that is transmitted along axon by activating ion channels further along the axon. Figure 1. **A.** view of an idealized action potential shows its various phases as the action potential passes a point on a [|cell membrane]. **B.** Recordings of action potentials are often distorted compared to the schematic view because of variations in [|electrophysiological] techniques used to make the recording.

__Chemical Transmission and the Synapse__ __Synapses__
 * 2/28/12 (Neuronal Structure and Function, part 3)**
 * [[image:dopamine_synapse_image.jpg width="406" height="395"]] || [[image:synapticcleft_TEM_image.jpg width="353" height="302"]] ||

__Synaptic transmission animation__


 * Neurotransmitters**

Neurotransmission activity site (See especially the **Neurotransmitter Action** activity tab)


 * [[image:patch_clamp_set-up_pic.jpg width="326" height="301"]] || [[image:patch_clamp_procedure_cartoon.gif width="374" height="296"]] ||
 * [[image:MSN_patch_pic.jpg width="328" height="314"]] || [[image:tonic_and_bursting_neurons_image.gif width="464" height="300"]] ||

Finish discussion of neuronal synaptic transmission and response
 * 2/29/12 (Stimulus and Response: Reflex Arc Lab)**

Lab 14A: Neuromuscular Reflexes (with Accelerometer)

Continue EKG lab.
 * 3/1/12 (Stimulus and Response: Reflex Arc Lab, cont,)**

"**Reflex relay**" game Two teams: Knee-jerk reflex team vs. auditory cue response team
 * 3/2/12 (Stimulus and Response, cont,)**


 * EKG Lab wrap-up** (The lab was a demonstration of the difference between a two-neuron reflex arc (Involuntary) and a multi-step (voluntary) response pathway).


 * Written response activity**: Did your data match the results as expected after completion of the "Reflex Relay"? Detail how and explain what they means. If your results did not match the expected results, explain how they differed and propose why this was the case. Compare and contrast your groups results with one other group.


 * Multi-step reflex responses** (ex. pain withdrawal reflex)




 * Receptors**: to detect a stimulus; receptors can be sensory cells or nerve endings of sensory neurons.2.


 * Sensory neurons**: to receive messages across synapses, from receptors and carry them to the central nervous system (spinal cord or brain)3.


 * Relay neurons**: to receive messages, across synapses, from sensory neurons, and pass them to the motor neurons that can cause an appropriate response.4.


 * Motor neurons**: to receive messages, across synapses, from relay neurons and carry them to an effector.5.


 * Effectors**: to carry out a response after receiving a message from a motorneuron; effectors can be muscles, which respond by contacting, or glands,which respond by secreting.



**HW:** Two Neuron Knee-Jerk Reflex Arc Complete this online activity and bring a print out of the completion page to class on Monday.

Label the Pain Withdrawal Reflex Arc diagram with **ALL** elements and descriptions and bring to class on Monday.

Review **Pain withdrawal reflex arc HW** Revisit synaptic transmission (synaptic integration)
 * 3/5/12 (Stimulus and Response, cont,)**


 * 3/6/12**
 * Finish Synaptic integration sheet**

Detailed view of a neuromuscular junction: 1. **[|Presynaptic] terminal**: Axon terminal of presynaptic neuron. 2. **[|Sarcolemma]**: the [|cell membrane] of a muscle cell (skeletal, cardiac, and smooth muscle).[|[][|1][|]] It consists of a true cell membrane, called the [|plasma membrane], and an outer coat made up of a thin layer of polysaccharide material that contains numerous thin collagen fibrils. At each end of the muscle fiber, this surface layer of the sarcolemma fuses with a tendon fiber, and the tendon fibers in turn collect into bundles to form the muscle tendons that then insert into bones. The membrane is configured to receive and conduct stimuli. 3. **[|Synaptic vesicle]**: Membrane bound vesicle containing neurotransmitter. 4. **[|Nicotinic acetylcholine receptor]**: Post-synaptic receptor ion channel that binds acetylcholine. 5. **[|Mitochondrion]**
 * Motor end plates**: A **neuromuscular junction** (**NMJ**) is the [|synapse] or junction of the [|axon] terminal of a [|motor neuron] with the **motor end plate**, the highly-excitable region of [|muscle fiber] [|plasma membrane] responsible for initiation of [|action potentials] across the muscle's surface, ultimately causing the muscle to contract. In vertebrates, the signal passes through the neuromuscular junction via the [|neurotransmitter] [|acetylcholine].

//"endorphins can act as painkillers//
 * Pain perception and endorphins as analgesics** (Pain perception)
 * endorphins (a.k.a. enkephalins) = pain-inhibiting neurotransmitters
 * produced by reticular formation (hypothalamus neurons) in brain
 * descending fibers synapse at the spinal cord dorsal horn
 * release endorphins into synapse between sensory neurons and ascending pain neurons
 * endorphins have specific receptor sites on post-synaptic neurons
 * inhibitory action
 * open K+ channels
 * close Ca+2 channels
 * hyperpolarizing post-synaptic membrane
 * act as pain killers by inhibiting pain signals along ascending pain neurons"
 * (from http://intranet1.canacad.ac.jp:3445/BiologyIBHL2/5045)




 * 3/7/12** (Capstone release day - no class)

Brain anatomy, neuron structure and function A.S.: E.5.1, E.5.2, 6.5.1, 6.5.2, 6.5.3, 6.5.4, and 6.5.5.
 * 3/8/12 (Test - Day 1)**

Brain anatomy, neuron structure and function A.S.: 6.5.6, E.4.1, E.4.2, E.1.1, E.1.2, E.1.3, and E.5.7.
 * 3/9/12 (Test - Day 2)**


 * NEXT: New Section Starts on Wednesday 4/4/12 (Brain Function, Somatosensory Perception and Transmission)**