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

Model brain diagrams

Interactive brain tutorial
Turn in brain structures function definitions
Finish model brain diagrams
Intro to brain dissections

Begin brain dissections

Continue brain dissections

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

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.

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


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.

2/28/12 (Neuronal Structure and Function, part 3)
Chemical Transmission and the Synapse

Synaptic transmission animation


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


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

Lab 14A: Neuromuscular Reflexes (with Accelerometer)

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

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

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.

Spinal Cord Grey (cell bodies) and White (myelinated axons) matter.

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.

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

Finish Synaptic integration sheet

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.
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

Pain perception and endorphins as analgesics (Pain perception)
"endorphins can act as painkillers
  • 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


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

3/8/12 (Test - Day 1)
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.

3/9/12 (Test - Day 2)
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.

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