Physiology EXAM 3 FINAL

PNS made up of nerve cell fibers (axons) (grouped into _______) outside the CNS that transmit information to and from the CNS

nerves

The 12 pairs of nerves that connect the PNS with the brain are called __________ nerves, and the 31 pairs that connect with the spinal cord are called _________ nerves

cranial, spinal

All spinal nerves of the PNS and most cranial nerve contain both sensory and efferent fibers (a few cranial nerves carry only _______ fibers)

sensory

I. Afferent (sensory) division II. Efferent (motor) division A. somatic nervous system B. autonomic nervous system (ANS) 1. sympathetic division 2. parasympathetic division (3. enteric division?)

Divisions of the PNS

Afferent Division is made up of sensory neurons that carry info from receptors in the periphery to the CNS, the cell bodies of these neurons are located outside the CNS in groups called ____

ganglions

From the cell body, one process extends (within a cranial or spinal nerve) out to the receptor; another process passes into the _____. The receptors sense the external (e.g., eye or ear) or internal (e.g., blood pressure) environment

CNS

Somatic nervous system made up of all the axons of neurons (called motor neurons) going from the CNS (via cranial or spinal nerves) to ______ muscles

skeletal

The cell bodies of the neurons in somatic nervous system are in groups in the ______ or ________--- their axons are myelinated

brain, spinal cord

There is only a _______ axon between the CNS & the skeletal muscle cell in somatic nervous system

single

The transmitter released onto the muscle cell in somatic nervous system is always ___________--- always excite (never inhibit) the muscle cell

Acetylcholine

Autonomic nervous system made up of all the axons of neurons going from the CNS (via cranial or spinal nerves) to smooth muscle, cardiac muscle, and _____

glands

A given cranial or spinal nerve in autonomic nervous system may carry either sympathetic or parasympathetic fibers, but not ___

both

Autonomic nervous system fibers can lead to excitation or inhibition of the effector organ--- always involves a ____ _____ ____ (connected by a synapse) between the CNS & the effector organ

two neuron chain

In the autonomic nervous system, the cell body of the first neuron in the chain is located in the _________

CNS

In the autonomic nervous system, the cell body of the second neuron in the chain (& the synapse between the first and second neurons) is located outside the CNS in a ____ (called an autonomic ganglion) of cell bodies

cluster

Usually, the ganglia of the sympathetic fibers (sympathetic ganglia) lie close to the _________, forming chains of ganglia known as sympathetic chains or trunks (exceptions: prevertebral ganglia such as celiac ganglion)

spinal cord

The parasympathetic ganglia lie _____________ the effector organ (with a few exceptions in the head)

atop, within

In both sympathetic and parasympathetic sympathetic fibers running between the CNS and a ganglion are called preganglionic fibers; those running from the ganglion to the effector organ are known as ____ fibers

postganglionic

If fibers releasing acetylcholine as their neurotransmitter are called ______fibers, and include: i. somatic NS fibers (not part of the ANS) ii. most preganglionic fibers of both the sympathetic and parasympathetic divisions of the ANS iii. most postganglionic fibers of the parasympathetic division of the ANS

cholinergic

Fibers releasing norepinephrine as their neurotransmitter are called _____ fibers, and include most post ganglionic fibers of the sympathetic division of the ANS

adrenergic

one set of postganglionic cells in the sympathetic division never develops axons; instead, the cells of this “ganglion” release their “transmitter” directly into the _____

bloodstream

this “ganglion,” called the adrenal medulla, is thus an endocrine gland the secretion of which is controlled by the _____ _____ ____

sympathetic preganglionic fibers

the adrenal medullae release both ____ ___ _____ , which are transported all over the body and which here are properly called hormones rather than neurotransmitters

epinephrine & norepinephrine

These hormones may effect (1) the same receptors as the norepinephrine released from other________ ____ ____ , or (2) other receptors far from the sympathetic postganglionic fibers (thus these latter receptors are activated only by the circulating epinephrine & norepinephrine)

sympathetic postganglionic fibers

some (not all) organs are reached by both sympathetic postganglionic & parasympathetic postganglionic fibers; whatever effect one ANS division has, the other division (with a few exceptions) has the ____ ____

opposite effect

A generality regarding the actions of the two ANS divisions is that the sympathetic division mobilizes the body during activity or stress, whereas the _____ _____ promotes maintenance functions and conserves body energy

parasympathetic division

A group of “___ ___ ____” mechanisms controls the kinds of substances that leave the blood and enter the interstitial fluid of the brain, thus precisely regulating the chemical composition of this fluid.

blood brain barrier

____ ___ ___ fills cavities within the brain and surrounds the brain & spinal cord, providing a cushion against jolts

Cerebrospinal fluid (CSF)

All molecules contain negatively and positively charged particles _____ and _____

electrons, protons.

Some molecules have more _______________________, or vice versa, giving them a net electric charge.

electrons than protons

The most notable of these in solution in the body are inorganic ions, especially ___, ____, and ____

Na+, K+, Cl-.

The ___ and intracellular fluid both contain many charged particles, and the distribution of these are important in neuron function.

ECF

An ___ ____ draws + and – charges together; like charges repel each other.

electric force

When oppositely charged particles come together, the force of attraction can be used to _________________. (To separate oppositely charged particles, energy must be used.)

perform work

Thus, separated electrical charges of opposite sign have the “potential” of doing work (if they are allowed to ________________)

come back together again

This potential to do work is called an electric potential, or the potential difference, often shortened to just ____________.

Potential

It is measured in _______ (V), but in living systems the separated charge is so small that the potentials are measured in millivolts (mV); one mV = 0.001 V.

Volts

The attraction between opposite charges tends to make them flow; the movement of electric charge is called ______________.

Current

The amount of current depends on: • the potential difference (voltage) • the nature of the material lying between the separated charges; the hindrance to the movement of charge through a material is called ________

resistance

Materials with high resistance to current flow are insulators, Materials with low resistance to current flow are _____________

conductors (iron, steel)

more current is achieved by raising the voltage or by lowering the resistance, as given by Ohm’s law

current = voltage/resistance

Pure water is a poor conductor of electricity because it contains few ___________________.

charged groups

When salt is added to the water (as in the body), it becomes a good _____________ (with a low resistance) as the Na+ and Cl- ions provide charges that can carry the current.

conductor

Lipids, which contain very few charged groups, have a high electrical resistance; thus, the lipid plasma membrane is a region of __ ___ ___that separate two water compartments of low resistance -- the membrane is good at separating opposite charges.

high electrical resistance