Title: Physiology 2130 / Module 6: Nervous System

Q: The nervous system has 2 divisions, the [...] and the [...].
A: central nervous system (CNS); peripheral nervous system (PNS)

Q: The CNS is made up of the [...] and [...].
A: brain; spinal cord

Q: The PNS consists of the [...] that branch out from the [...] and [...].
A: nerves; brain; spinal cord

Q: The peripheral nervous system can be further divided into the [...] and [...] nervous systems.
A: autonomic; somatomotor
Extra: Somatomotor = SOMATIC

Q: The [...] is the connection between the nerves and other organs.
A: autonomic nervous system

Q: The [...] is the connection between the nerves and skeletal muscles.
A: somatomotor nervous system

Header: Label the part of the brain:

Q: The left hemisphere sends signals to activate muscles on the [...] of the body.
The right hemisphere sends signals to activate on the [...] side of the body
A: right; left

Q: Sulci are the [...] on the surface of the brain.
[...] are the bumps on the surface of the brain.
Their purpose is to increase the [...] of the brain.
A: dips; Gyri; surface area

Q: The location of sulci and gyri are [...] between individuals in terms of their shape and size.
A: consistent

Header: Label the Lobe:

Q: The [...] is where the nerves from each eye meet.
A: optic chiasma

Q: Optic nerves cross over at the optic chiasma and continue to the [...] of the thalamus. From there, they extend to the respective hemisphere on the primary visual area of the [...].
A: lateral geniculate bodies; occipital lobe

Q: The brain is made up of [...] and [...].
A: neurons; glial cells

Q: [...]  make up 90% of brain and provide the necessary environment for neurons to function properly.
A: Glial cells

Q: Types of neurons are:
1. [...]
2. [...]
3. [...]
A: Unipolar; Bipolar; Multipolar
Extra: Unipolar Neurons have 1 process extending from the cell body. They're generally located in the peripheral nerves outside the CNS and are typically sensory in nature, transmitting signals to & from the spinal cord. Their cell body lies in the middle and off to one side of the axon.
Bipolar Neurons have 2 processes extending from the cell body. They're a form of specialized neurons that can be found in the retina of the eye.
Multipolair Neurons contain many branching dendrites and 1 axon. They're most common in the CNS.

Q: Bipolar neurons have 2 [...] extending from the cell body.
A: processes/axons to terminal

Q: [...] neurons are found in the retina of the eye.
A: Bipolar

Q: Neurons that have 1 process extending from its cell body are [...].
A: unipolar

Q: Unipolar neurons are located in the [...] nerves and are [...] by nature.
A: peripheral; sensory

Q: Multipolar neurons have many branching [...] but one [...].
A: dendrites; axon

Q: Multipolar neurons are most common in the [...].
A: CNS

Q: Glial cells maitain the [...] of the CNS.
A: internal enviornment

Q: Glial cells regulate [...] and the [...] environment of the brain.
A: nutrients; interstitial

Q: 3 types of glial cells are:
1. [...]
2.[...]
3.[...] (which produce myelin)
A: Astrocytes; Microglia; Oligodendrocytes

Q: [...] are the language of the nervous system.
A: Action potentials

Q: The weight of an object is "coded" into the action potential. The heavier the object, the more [...] per second. This is called [...].
A: action potentials; neural coding

Q: There is a directly proportional relationship between weight (of an object) and [...] (of action potentials).
A: frequency

Q: Nerve cells communicate with one another by a [...].
A: chemical synapse

Q: At a chemical synapse, a [...] will release a neurotransmitter to which will affect the [...].
A: presynaptic nerve; postsynaptic nerve

Q: The axon terminal of a presynaptic nerve contains:
1. [...]
2. [...]
3. [...]
A: Voltage-Gated Ca++ Ion Channel; Mitochondria; Synaptic Vesicles with Neurotransmitters

Q: The postynaptic nerve contains:
1.[...]
2.[...]
A: Chemical Receptors; Ligand-Gated Ion Channels

The events that occur at a chemical synapse are:
1. Presynaptic nerves synthesize neurotransmitters that are stored in synaptic vesicles
2. The action potential in the presynaptic nerve depolarizes the memebrane and activates Ca++ channels, which allows Ca++ to flow into the axon terminal.
3. Ca++ causes vesicles to fuse to the wall of terminal and release neurotransmitters through exocytosis.
4. Neurotransmitters diffuses across synaptic cleft and act on chemical receptors on the postsynaptic cell membrane.
5. Receptors cause opening of ligand-gated ion channels.
6. Postsynaptic membrane potential changes; either hyperpolarizes or is depolarized depending on the neurotransmitter.

Hyperpolarization of the postsynaptic neuron decreases likelihood of an action potential being fired. This would be a inhibitory response.
Depolarization increases likelihood of an action potential being fired, this would be an excitatory response.

Q: [...] are chemicals released by neurons.
A: Neurotransmitters

The four groups of neurotransmitters are:
1.Acetylcholine
2. Biogenic Amines
3.Amino Acids
4.Neuropeptides

Q: Catecholamines are a type of [...].
A: biogenic amine

Q: Some catecholamines are:
1. [...]
2.[...]
3.[...]
A: Dopamine; Norepinephrine; Epinephrine

Q: Amino acids can be classified as [...] or [...].
A: excitatory; inhibitory

Excitatory amino acids are: glutamate and aspartate.
Inhibitory amino acids are: GABA and glycine.
Extra: Gamma-Amino-Butyric Acid = GABA

Q: With muscles, a single action potential in a neuron always results in a single action potential in the [...].
A: muscle cell

Q: With neurons, a single action potential on a presynaptic neuron will NOT produce an action potential on the [...].
A: postsynaptic neuron

Q: EPSP is a local event that diminishes with [...] and [...], aka [...] potential.
A: time; distance; graded

Q: Excitatory neurotransmitters create [...] by opening gates that allow [...] into the cell and create a local depolarization.
A: excitatory postsynaptic potential (EPSP); positive ions

Q: With EPSPs the local depolarization will depolarize a region on the dendrite but it will not [...] an [...] because there are no voltage gated channels on the dendrites or cell body.
A: fire; action potential

Q: For an EPSP to fire an action potential in the postsynaptic neuron, the postsynaptic neuron must be depolarized at the [...].
A: axon hillock

Q: To cause an action potential the EPSPs must have a strong enough [...] to spread to the axon hillock.
A: positive current

Q: The strength of a EPSP can be increased by:
1. [...]
2.[...]
A: Spatial Summation; Temporal Summation

Q: [...] is the additive effect produced by many EPSPs that have been generated at many different synapses on the same postsynaptic neuron at the same time.
A: Spatial summation

Q: [...] is the additive effect produced by many EPSPs that have been generated at the same synapse by a series of high-frequency action potentials on the presynaptic neuron.
A: Temporal summation

Q: Inhibitory neurotransmitters create a hyperpolarization called an [...].
A: inhibitory postsynaptic potential (IPSP)

Q: Inhibitory neurotransmitters produce a hyperpolarization by openning chemically gated channels that let [...] in or [...] out.
This local hyperpolarization is called an [...].
A: Cl-; K+; inhibitory postsynaptic potential
Extra: Inhibitory Postsynaptic Potential = IPSP

Spatial and temporal summations can occur for IPSPs and EPSPs, and create larger hyperpolarizations or stronger depolarizations respectively.

Q: IPSP and EPSP can occur at the same time in the same postsynaptic cell, but the potential with the greater number will determine whether or not the cell fires.  This ‘battle’ of postsynaptic potential is called [...].
A: synaptic integration
Extra: The cell may fire an AP if there are many more EPSPs than IPSPs. But if the # of IPSPs outnumber the EPSPs, the cell will be shut off.

Q: The [...] is how the brain controls muscles to perform voluntary movement.
A: somatic motor system

Q: When special receptors in the muscles send info to the brain about the position of the limbs this is called [...].
A: proprioception

The components of the motor system are:
1. The Supplementary Motor Area (of the brain)
2. The Premotor Area (of the brain)
3. The Primary Motor Cortex Area (of the brain)
4. Basal Ganglia (also part of the brain)
5. Spinal Pathways
6. Motor Nerves
7. Muscle Receptors

Q: Decisions about movement are made in the [...] but developing the appropriate strategy for the movement is done by the [...].
A: prefrontal cortex; premotor cortex
Extra: The primary motor cortex processes input from skeletal muscles throughout the body, while the motor association area (premotor cortex) & the prefrontal cortex (PFC) integrate movement info with other sensory inputs to generate perception (interpretation) of stimuli.

Q: From the premotor cortex, the information travels to the [...] which will program the motor sequences, crucial for complex and [...] movements.
A: supplementary cortex; repetitious
Extra: ie. opening and closing hand

Q: The primary motor cortex has a topographical representation of the body on its surface, called the [...].
A: motor homunculus

Q: The "program" from the supplementary cortex is sent to the [...] which activates the specific neurons necessary to activate a particular muscle.
A: primary motor cortex

Q: Signals from the primary motor cortex travel down the [...] through the [...].
A: spinal cord; corticospinal tract

Q: The [...] is the major motor pathway from the primary motor cortex to the motor neurons, it begins in the motor cortex and goes down to the brain stem.
A: corticospinal tract

Q: At the medulla most nerve fibers (80%) cross to the [...] of the body, while 20% remain [...] until they reach the point on the spinal cord where they synapse.
A: contralateral side; ipsilateral
Extra: Contralateral = Opposite Sides
Ipsilateral = Same Side

Q: Special receptors in the muscles that send signals back to the brain are:
1. [...] - detect muscle stretch, length and rate of change of length.
2. [...] - detect muscle tension.
A: Muscle Spindles; Golgi Tendon Organs

Q: Real contractile muscle cells are called [...].
A: extrafusal fibers

The muscle spindle consists of the following:
1. Intrafusal Muscle Fibers
2. Central Sensory Region
3. 2 sets of Gamma Motor Neurons that activate the (1.)
4. Sensory Neuron

Q: In proprioception with muscle spindles:
1. The [...] of muscle spindles strecthes when the whole muscle stretches.
2.  It is sensitive to changes in shape, so it will depolarize and trigger action potentials in the [...].
3. The sensory nerve sends the info to the [...].
A: sensory region; sensory nerve; brain

Q: The more stretched the sensory region (of the muscle spindle) the more [...] it is, so the more [...] sent to the brain.
A: depolarized; action potentials

Q: [...] are used to send signals so extrafusal muscle fibers contract.
A: Alpha motor neurons
Extra: Extrafusal Fibers = Contraction of Muscle → Activated by ALPHA
Intrafusal Fibers = Proprioception → Activated by GAMMA

Q: [...] keep the muscle spindles operating during a contraction by sending signals to the intrafusal fibers.
A: Gamma motor neurons
Extra: Extrafusal Fibers = Contraction of Muscle → Activated by ALPHA
Intrafusal Fibers = Proprioception → Activated by GAMMA

Q: During muscle contractions, alpha motor neruons send signals to the [...] muscle and gamma motorneurons to the [...] muscle.
This is called [...].
A: etxrafusal; intrafusal; alpha-gamma coactivation

Q: [...] ensures that muscle spindles continue to send info about proprioception to the brain during muscle contractions.
A: Alpha-gamma coactivation
Extra: That is, it ensures that muscle spindles continue to send information to the brain about muscle & limb position.

Q: [...] neurons carry signals towards the CNS (to the brain).
[...] neurons carry signals away from the CNS.
A: Afferent; Efferent

The reflex arc occurs as follows:
1. Sensory receptor has a receptor potential that produces an action potential.
2. Action potential reaches the afferent neuron (aka. sensory).
3. There is a synapse the action potential must be transmitted across to reach the spinal cord.
4. An action potential is produced on the interneurons.
5. An action potential is eventually produced on the efferent neuron (aka motor).
6. Effector organ is activated.
Extra: interneurons = in btwn the rest of the pathway

Q: A reflex arc does not require any output by the [...] to cause the muscle (effector) to contract.
A: brain

Q: The [...] is an example of a reflex arc.
A: stretch reflex

Seuqence of events for the strech reflex:
1. Tapping Tendon = small stretch of quadricep;
2. Stretching the Muscle = stretch of muscle spindle;
3.Muscle spindles being stretched triggers an action potential in the afferent neuron which will enter spinal cord;
4. The motor nerve in the quadricep will activate while the muscles of the hamstring are inhibited;
5. Quadriceps contract and the hamstring relaxes, the lower leg kicks out.

Q: The cerebellum contributes to generating accurate [...], correcting [...] movements and modifying the [...].
A: limb movements; ongoing; strength of some reflexes

Header: Label the parts involved with helping the cerebellum generate accurate movements and correct ongoing ones:

Q: The cerebellum must receive info from 2 places:
1. The [...] as info is being sent out to the muscles;
2. [...]
A: motor cortex; Proprioception

The components of the limbic system are the hypothalamus,amygdala,hippocampus,cingulate cortex and the septum.

Q: The key function of the limbic system is to link the higher thought processes of the brain with [...] responses.
A: emotional
Extra: Allows us to respond to changes in our envrionemnt, since it also controls behaviours like learning, pain, motivation, feeding, etc.

Q: The hypothalamus plays a key role in [...] and regulation of the [...] mainly through directing the release of hormones.
A: homeostasis; endocrine system
Extra: Regulates Circadian Rhythm; Cardiovascular; Emotional Behaviors; Food Intake, etc.

Q: The [...] is regulated by the hypothalamus and regulates the realse of hormones
A: pituitary gland
Extra: The pituitary gland is also known as the master gland.

Q: The [...] nervous system is not under voluntary control.
A: autonomic

Q: The autonomic nervous system can be divided into [...] and [...].
A: parasympathetic; sympathetic

Q: The [...] is involved in fight or flight situations.
It will increase heart rate, blood pressure, dilate airways and blood vessels to the muscles and shut down the digestive tract.
A: sympathetic nervous system

Q: The [...] is involved in relaxation, as it stores and conserves energy.
It slows the heart rate and lowers blood pressure.
A: parasympathetic nervous system

Q: Nerves of the [...] nervous system exit the spinal cord in the thoracic and lumbar (central) regions of the cord.
A: sympathetic
Extra: These preganglionic neurons will synapse in ganglia onto a second postganglionic nerve that will travel to the effector/target organ of interest.
Ganglion = a group of neurons in the peripheral nervous system;
Preganglionic = from the CNS to ganglia
Postganglionic = from the ganglia to the effector organ
Preganglionic synapse in the ganglia onto second postganglionic nerve that travels to effector organ.

Q: The [...] nervous system exits at the brain stem and the very low sacral region of the spinal cord.
A: parasympathetic
Extra: These preganglionic nerves will synapse onto a postganglionic nerve very near the effector organ of interest. This nerve will then synapse onto the target organ.

Header: Label the diagram accordingly (hint: pink = neurotransmitters).

Header: Label the diagram accordingly (hint: pink = neurotransmitters):

Q: The neurotransmitter released by the parasympathetic postganglionic neuron is always [...].
A: ACh

Q: The neurotransmitter released by the sympathetic postganglionic neuron to the effector organ is usually [...] but sometimes it is [...].
A: norepinephrine; ACh

Q: The axon of the postganglionic neuron in the sympathetic nervous system is [...] than that of the parasympathetic nervous system.
A: longer

Header: What are the effects of the PSYN and SYN on this organ?