Explain the anatomical organization of the nervous system
The central nervous system (CNS) consists of the brain and spinal cord.
The peripheral nervous system (PNS) consists of nerves and ganglia.
The sensory division of the peripheral nervous system detects stimuli and conducts action potentials to the central nervous system. The CNS interprets incoming action potentials and initiates action potentials that are conducted through the motor division to produce a response. The motor division is divided into the somatic nervous system and the autonomic nervous system
Compare and contrast the white and grey matter of the spinal cord.
Gray matter - consists of groups of neuron cell bodies and their dendrites, where there is very little myelin. (dorsal horn, ventral horn, lateral horn)
White matter - consists of bundles of parallel axons with their myelin sheaths, which are whitish in color. (Columns: ascending tracts (posterior column, lateral column), Descending tracts (anterior column))
Describe ascending and descending pathways of the spinal cord
Explain the various mechanisms for how the central nervous system is protected
Compare and contrast cranial and spinal nerves
Compare and contrast afferent neurons with efferent neurons
Identify differences between the somatic motor efferent pathway and the autonomic efferent pathway
Define a reflex = neural response that doesn’t require cognitive thought
persons finger touches a hot stove. the heat stimulates pain receptors in the skin, and action potentials are produced. sensory neurons conduct the action potentials to the spinal cord, where they synapse with interneurons. The interneurons, in turn, synapse with motor neurons in the spinal cord that conduct action potentials along their axons to flexor muscles in the upper limb. these muscles contract and pull the finger away from the stove.
Identify and describe two basic types of reflexes
Explain why humans (and other animals) have the tendon-stretch reflexes
Explain why humans (and other animals) have withdrawal reflexes
Compare and contrast the two divisions of the autonomic nervous system
Sympathetic - Flight or Fight
- To respond to life threatening stress
- Most organs
- Utilizes Sympathetic Chain (of Ganglia)
- Neurotransmitters and Hormones
Parasympathetic - Rest and Digest
- For homeostasis
- Most organs
- Vagus n.
Discuss what is meant by pre- and post-ganglionic neurons.
Compare and contrast neurons and non-neuronal cells
Explain the primary difference between chemical and electrical signaling within the nervous system
Compare and contrast graded potentials with action potentials
Discuss the sequence of events that define an action potential
Explain mechanisms for an action potential to get from point A to point B
when a stimulus is applied, following a neurotransmitter activation of chemically gated channels Na+ channels open very briefly, and Na+ diffuses quickly into the cell. this movement of Na+, which is called a local current, causes the inside of the cell membrane to become positive, a change called depolarization. this results in a local potential. when the depolarization is strong enough, Na+ enters the cell so that the local potential reaches a threshold value. this threshold depolarization causes Na+ to open. K+ channels also open. as more Na+ enters the cell, depolarization occurs until a brief reversal of charge takes place across the membrane. the charge reversal causes Na+ channels to close and more K+ channels to open. Na+ stops entering the cell and K+ leaves the cell. this repolarizes the cell membrane to its resting membrane potential. at the end of depolarization, the charge on the cell membrane briefly becomes more negative than the resting membrane potential; this condition is called hyperpolarization
Describe the events at a synapse
1. action potentials arriving at the presynaptic terminal causes voltage-gated Ca++ channels to open
2. Ca++ diffuses into the cell and causes synaptic vesicles to release neurotransmitter molecules
3. Neurotransmitter molecules diffuse from the presynaptic terminal across the synaptic cleft
4. Neurotransmitter molecules combine with their receptor sites and cause chemically-gated Na+ channels to open. Na+ diffuses into the cell or out of the cell and cause a change in membrane potential.
Compare and contrast the events at the neuromuscular junction with neural synapses
1. at neuromuscular junction neurotransmitter is always acetylcholine.
2. at nerve synapses it is sometimes acetylcholine.
3. the neurotransmitter released by exocytosis in both by using calcium ions to move the vesicles of neurotransmitter to the pre-synaptic membrane.
4. the neurotransmitter travels by diffusion across the synapse in both.
5. both hav receptors to the neurotransmitter causing sodium to enter the post synaptic membrane, and also sodium enters the sarcolemma(cell membrane of muscle cell) causing depolirsation.
6. on cell membrane of muscle cells, there are T-tubules. there is none on post synaptic nerve. the depolarisation travels down the T-tubules to depolarise the sarcoplasmic recticulum, releasing calcuim, in order to bind to the troponin to move the tropomysin on the actin microfibres so the myosin head binds.
7. both of the post synpatic nerve and the sarcolemma have sodium/potasium pump to restore membrane polarization.
8. both of the synapse and neuro musclar junctions uses enzymes to break down the neurotransmitter in the synaptic cleft.