Exam 2 Part four Flashcards Preview

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Flashcards in Exam 2 Part four Deck (103):

Resting potential is

The imbalance of electrical charge that exists between the interior of electrically excitable nerve cells and their surroundings.


The difference in charge between the interior & exterior of the cell is called

Resting membrane potential


For the nerve impulse, what does the resting membrane potential have?

The exterior of the cell has a net positive charge and the interior has a net negative charge


During depolarization what voltage-gated ion channel opens first and second?

Na+ gates open before K+ gates


Depolarization occurs because

More Na+ diffuse into the cell than K+ diffuse out of it


True or false: The sodium-potassium pump is involved in establishing the resting membrane potential



True or false: The nerve impulse is an electrical current that travels along dendrites or axons



An action potential occurs when?

A neuron is conducting a nerve impulse


The state during which no nerve impulse is being conducted

Resting potential


State during which the neuron is actively involved in conducting a nerve impulse

Action potential


The resting potential is at?

-70mv (millivolts)


The difference in ion displacement and thus the resting potential is largely maintained by a protein channel called the

Na+/K+ pump


The Na+/K+ pump is

Powered by ATP, it actively pumps Na+ ions out of the cell and K+ ions into the cell


Threshold is

The point at which increasing stimuli trigger the start of an afferent nerve impulse


The all-or-nothing for a nerve impulse means that

The ion channels are either open or closed; there is no half-way position


Define Depolarization for a nerve impulse

Reversal of the resting potential in excitable cell membranes when stimulated


Active transport for a nerve impulse is

When a neuron is at rest a charge difference is maintained between the inside and outside of the cell, this charge difference is produced & maintained largely by active transport using sodium-potassium pumps


What is diffusion of a nerve impulse?

When the K+ (potassium) and Na+ (Sodium) diffuse in and out of the neuron during an action potential


Monosynaptic reflex is

The simplest of all reflexes. The sensory axons synapse directly on the motor neurons, whose axons project to the effector


Give an example of a monosynaptic reflex

The patellar reflex, which physicians use to assess the functioning of the spinal cord


Polysynaptic reflexes have

More complex neural pathways that exhibit a number of synapses involving interneurons within the reflex arc. More prolonged delay.


An example of a polysynaptic reflex is

The crossed-extensor reflex, the reflex that supports postural muscle activity when you withdraw your foot from a painful stimulus


Effectors can be

1) A muscle, gland, or organ capable of responding to a stimulus, especially a nerve impulse
2) A nerve ending that carries impulses to a muscle, gland, or organ and activates muscle contraction or glandular secretion


Receptors are

Structures that detect stimuli


Glands are

A cell, a group of cells, or an organ that produces a secretion for use elsewhere in the body or in a body cavity or for elimination from the body


Considering "the all-or-none" rule of muscle contraction, how is it that we are able to have smooth & refined body movements?

While the muscle fibers obey all the all-or-none principe, the force and precision of muscle movement can be varied, depending on how many muscle fibers and motor units are activated


Muscle fatigue means

That you have exhausted the muscle past the point of it being able to use aerobic respiration


Define aerobic

A form of cellular respiration that requires oxygen in order to generate energy


Muscle belly (body) is

Main region that shortens & thickens when it contracts, Creates the Action


If a muscle can only contract (shorten in length) explain how it is that we can "push" an object. Give an example

By levers. Olecranon process


What is the order of skeletal muscle development?

1) Mesoderm
2) Somite
3) Myotome
4) Muscle


Describe the relationship between mesoderm, somites & myotomes in skeletal muscle development

1) Skeletal muscle tissue formation is initiated during the fourth week of development from blocks of paraxial mesoderm that form somites
2) Cells w/in a somite differentiate into 3 distinct regions; one being myotome which gives rise to skeletal muscles


How do muscles maintain homeostasis?

They help regulate our body temperature


The autonomic nervous system (ANS)

Also called the autonomic motor. It innervates internal organs & regulates smooth muscle, cardiac muscle, & glands without our control, Also known as the visceral motor system or the involuntary nervous system. Has two further subdivisions; parasympathetic and sympathetic


Fight-or-flight response is

A physiological reaction in response to stress, characterized by an increase in heart rate and blood pressure, elevation of glucose levels in the blood, and redistribution of blood from the digestive tract to the muscles. These changes are caused by activation of the sympathetic nervous system by epinephrine (adrenaline), which prepares the body to challenge or flee from a perceived threat
(Sympathetic nervous system)


Gray matter in the brain is

Houses motor neuron & interneuron cell bodies, dendrites, telodendria, and unmyelinated axons


The white matter in the brain is

Derives its color from the myelin in the myelinated axons


Rest-and digest responses are

When parasympathetic activity dominates, healing and regeneration occur. The body performs activities like digesting, detoxifying, eliminating, and building immunity


What is collateral ganglia?

Any of the sympathetic ganglia located in front of the vertebral column, outside the sympathetic chain, close to the viscera and arteries. It is mainly involved in the innervation of abdominal and pelvic viscera.


Define mesencephalon

The midbrain. Only primary vesicle that does not form a new secondary vesicle


Define telencephalon

Arises from the prosencephalon & eventually forms the cerebrum


What is diencephalon

Arises from the prosencephalon & eventually forms the thalamus, hypothalamus, & epithalamus


The rhombencephalon is

The hindbrain


The prosencephalon is

The forebrain


The metencephalon arises from

The rhombencephalon & eventually forms the pons and cerebellum


The myelencephalon derives from

The rhombencephalon & eventually forms the medulla oblongata


The cerebrum is the location of

conscious thought processes & the origin of all complex intellectual functions. Identified as two large hemispheres on the superior aspect of the brain


Neurulation is

When the neuroectoderm undergoes dramatic changes to form nervous tissue structures


What is the primary germ layer derivative of neurons: brain & spinal cord, Glial cells: brian and spinal cord?



Pons are

A bulging region on the anterior part of the brainstem that forms from part of the metencephalon


The thalamus refers to

Paired oval masses of gray matter that lie on each side of the third ventricle. Forms the superolateral walls of the third ventricle


The hypothalamus is the

Anteroinferior region of the diencephalon.


Peduncles are

Three thick tracts that link the cerebellum with the brainstem


The medulla oblongata is

Formed from the myelencephalon. The most inferior part of the brainstem & is continuous with the spinal cord inferiorly


The central nervous system forms primarily from?

The embryonic neural tube


Caudal means

Towards the tail


Cephalic means

Relating to the head or the head end of the body. Situated on, in, or near the head. Cephalic is synonymous with cranial, relating to the cranium or head


Neural groove is

The gutterlike groove formed in the midline of the embryo's dorsal surface by the progressive elevation of the lateral margins of the neural plate, resulting in the formation of the neural tube. Also called medullary groove


Colliculi is

A small protuberance, especially one of two pairs in the roof of the midbrain, involved respectively in vision and hearing


Nerve growth factor is

A protein that promotes development of the sensory and sympathetic nervous systems and is required for maintenance of sympathetic neurons


A protein that stimulates the growth of sympathetic and sensory nerve cellS

Nerve growth factor


Describe neuron repair following damage



Why do neurons usually not repair in the CNS?

Limited due to several factors
1) Oligodendrocytes do not release a nerve factor, they inhibit axon growth by producing and secreting several growth inhibitory molecules
2) Large numbers of axons crowded within the CNS complicates regrowth activities
3) Astroctyes & connective tissue coverings can form scar tissue that obstructs axon regrowth


Neurotransmitter of the postganglionic fibers in the sympathetic division of the autonomic system

Norepinephrine (NE)


Chemical stored at the ends of axons that is responsible for transmission across a synapse



What are the 12 cranial nerves?

1) Olfactory
2) Optic
3) Oculomotor
4) Trochlear
5) Trigeminal
6) Abducens
7) Facial
8) Vestibulocochlear
9) Glossopharyngeal
10) Vagus
11) Accessory
12) Hypoglossal


The function and sensory/motor function for Olfactory cranial nerve

* Odor detection
* Sensory


The function and sensory/motor function for optic cranial nerve



The function and sensory/motor function for oculomotor, trochlear, and abducens cranial nerves

*Eye muscles
*Motor ?CHECK?


Function and sensory/motor function for trigeminal cranial nerve

*Three branches
*Face- sensory
*Chewing- motor


Function and sensory/motor function for facial cranial nerve

*Motor to face
*Sensory from tongue


Function and sensory/motor function for vestibulocochlear cranial nerve

* Hearing and balance
* Sensory


Function and sensory/motor function for glossopharyngeal cranial nerve



Function and sensory/motor function for vagus cranial nerve

Visceral- sensory
Throat- motor


Function and sensory/motor function for accessory cranial nerve

* Neck and upper back
* Motor


Function and sensory/motor function for hypoglossal cranial nerve

* Tongue
* Motor


Threshold level is

At the base of the hillock, or trigger zone, the stimulus must reach a specific threshold level in order to generate an action potential. At the threshold, a positive feedback look of Na+ influx will initiate


A damaged axon can regenerate if

At least some neurilemma remains


PNS axon regeneration depends upon 3 factors

1) Amount of damage
2) Neurolemmocyte secretion of nerve growth factors to stimulate outgrowth of severed axons
3) The distance between the site of the damaged axon and the effector organ


How do neurolemmocytes help repair a damaged axon?

Through a regeneration process called Wallerian degeneration


Cerebellum is

A large portion of the brain, serving to coordinate voluntary movements, posture, and balance. in back of and below the cerebrum and consists of two lateral lobes and a central lobe


Where are ganglia and nuclei located?

In the central nervous system, a collection of neuron cell bodies is called a nucleus.

In the peripheral nervous system, a collection of neuron cell bodies is called a ganglion


What does ganglia contain?

Mass of nerve tissue; a group of nerve cell bodies, especially nerve cells external to the brain or spinal cord


What does nuclei contain?

A mass of nerve cells in the brain or spinal cord in which nerve fibers form connections


Gray matter in the spinal cord is dominated by

The dendrites and cell bodies of neurons and glial cells and unmyelinated axons


White matter in the spinal cord is composed of

Primarily myelinated axons


Where is gray matter in the spinal cord located?

Centrally located, it resembles a letter H or a butterfly


The gray matter in the spinal cord may be subdivided into

Anterior horns, lateral horns, posterior horns, and the gray commissure


Gray Commissure is

A horizontal bar of gray matter that surrounds a narrow central canal. Contains unmyelinated axons and serves as a communication route between the right and left sides of the gray matter


White commissure is

A narrow band of white matter that crosses the midline of the spinal cord posterior to the central canal and posterior gray commissure


Gray matter and white matter in the brain

(Gray on outside, white in middle
* Gray matter: houses motor neuron and interneuron cell bodies, dendrites, telodendria, and unmyelinated axons
* White matter: Derives its color from myelin in the myelinated axons. Lies deep to the gray matter of the cortex. Within masses of white matter, the brain contains clusters of gray matter (cerebral nuclei)


What is ganglionic neuron?

autonomic motor neuron that has its body in a peripheral ganglion and projects its (postganglionic) axon to an effector


Ganglion Of Sympathetic Trunk are

Clusters of postsynaptic neurons located at intervals along the sympathetic trunks, including the superior cervical, middle cervical, and cervicothoracic ganglion, the thoracic, lumbar, and sacral ganglia, and the ganglion impar


Thoracolumbar is

Pertaining to thoracic and lumbar vertebrae


Cranial-sacral is

A therapy that uses gentle manual pressure applied to the skull, spine, and membranes to restore rhythmic flow to the craniosacral system, which includes the brain, spinal cord, cerebrospinal fluid, and surrounding membranes.


Sympathetic Postganglionic Neurons

Postganglionic fibers are long and unmyelinated.


Sympathetic Preganglionic Neurons

Preganglionic fibers are short and myelinated.


Overview of parasympathetic pathways

Preganglionic axons from the brain & spinal cord innervate the viscera in the head, neck and trunk


Overview of the sympathetic pathways

The right sympathetic


Ganglia in sympathetic is

Closer to CNS


Parasympathetic preganglionic neurons

Preganglionic fibers are long and myelinated.


Parasympathetic postganglionic neurons

Postganglionic fibers are short and not myelinated


Ganglion in parasympathetic is

Closer to organs