Alzheimer disease is caused by a decrease in the production of the neurotransmitter acetylcholine in the brain. Cholinesterase inhibitors, such as the drug donepezil, can slow the development of symptoms in the early-to-middle stages of Alzheimer disease, but they cannot stop the progression of the disease. The donepezil molecule has a shape that allows it to attach to the active site on cholinesterase, thereby preventing the cholinesterase from binding to acetylcholine In the diagram above, acetylcholine and donepezil are numbered A. 1 and 2 respectively B. 2 and 1 respectively C. 3 and 4 respectively D. 4 and 3 respectively

How does donepezil affect synaptic transmission? A. Donepezil breaks down acetylcholine so that less acetylcholine is available in the synapse. B. Donepezil replaces cholinesterase so that more acetylcholine is available in the synapse. C. Donepezil blocks the release of acetylcholine so that less acetylcholine is available in the synapse. D. Donepezil prevents the breakdown of acetylcholine so that more acetylcholine is available in the synapse.

 Stimulation of a sensory neuron produces an action potential. An abnormal pattern in this action potential can be used to detect MS in its early stages. The graph below illustrates the membrane potential of a normal neuron after stimulation.

 Which of the following types of ion movement across an axon membrane would cause the action potential to change during the interval from 0.2 ms to 0.4 ms? A. Sodium ions moving into the axon B. Sodium ions moving out of the axon C. Potassium ions moving into the axon D. Potassium ions moving out of the axon

 On the graph, the period from 0.5 ms to 1.0 ms represents the neuron’s A. refractory period, which is when repolarization occurs B. refractory period, which is when minimum depolarization occurs C. threshold period, which is when repolarization occurs D. threshold period, which is when minimum depolarization occurs

The Central Nervous System Chapter 13.3

Central Nervous Composition  The nervous system has distinct types of tissues and fluids:  White matter is any neuron with myelin.  Grey matter is any neuron without myelin.  Meninges are the tough membranes that surround and protect the CNS.  Cerebrospinal fluid acts as a shock absorber and a transporter of nutrients and wastes.

Spinal Cord  The spinal cord is composed of these tissues.  White matter comprises the outer layers as these are myelinated sensory and motor neurons.  Grey matter comprises the core as this is unmyelinated interneurons.  These interneurons are organized into a channel that goes directly to the brain.

 Sensory neurons approach the spinal cord in a bundle called the dorsal root.  Motor neurons leave the spinal cord in a bundle called the ventral root.

Structure of the Brain

 The largest part of the brain is the cerebrum.  It stores and processes sensory information, and initiates voluntary responses.  It is separated into the left and right hemisphere.  The left hemisphere is associated with the right side of the body and rational thought.  The right hemisphere is associated with the left side of the body and intuitive/creative thought.  The two hemispheres can act independently, but communication occurs between them through the corpus callosum.

 The cerebrum is covered in wrinkled tissue known as the cerebral cortex.  This is divided into 4 regions, each with associated functions: 1.Frontal Lobe 2.Temporal Lobe 3.Parietal Lobe 4.Occipital Lobe

Forebrain Structures  The forebrain also contains three other structures: 1.Thalumus – Acts as a waystation for incoming sensory information by directing it to the associated cerebrum lobe. 2.Hypothalumus – Works to control the endocrine system. 3.Olfactory Lobes – Receive and interpret smell sensations.

Hindbrain Structures  The hindbrain is comprised of 3 structures: 1.Cerebellum – Controls limb movements, muscle tone and balance. 2.Medulla Oblongata – The control center for the autonomic nervous system. 3.Pons – Acts as a bridge between the cerebellum and medulla.

Comparing Brains  We can compare brain composition of various animals to determine certain aspects.

Homework  Pg  Pg 430 Case Study  Pg