Human A&p Test 3: The Efferent Division Of The Pns

Front 1

Definition of nerve

Back 1

parallel bundles of peripheral axons (myelinated and unmyelinated) enclosed by successive wrappings of connective tissue.

Front 2

What surrounds each axon (myelin sheath)

Back 2

Endoneurium

Front 3

What wraps bundles of axons into fascicles

Back 3

perineurium

Front 4

What encloses bundles of fascicles and blood vessels

Back 4

epineurium

Front 5

What types of nerves exist.

Back 5

- mixed nerves, sensory nerves, motor nerves, somatic and autonomic.
- these peripheral nerves are either cranial or spinal.

Front 6

What are ganglion and what is the difference between ganglion of the afferent and efferent nerve fibers.

Back 6

Ganglia: collection of neuron cell bodies associated with nerves of PNS
- afferent ganglia are associated with sensory neurons
- efferent ganglia are associated with autonomic motor neurons.

Front 7

How do motor endings activate effectors?

Back 7

By releasing NT.

Front 8

General overview on Cranial nerves.

Back 8

- 12 nerve pairs: (first two pairs attached to forebrain and the rest originate in brainstem)
- cranial nerves deal with neck/head (with exception of vagus nerve)
- 3 pairs sensory
- 5 pairs motor
- rest mixed

Front 9

Gray matter of spinal cord is composed of?

Back 9

- neuron cell bodies
- unmyelinated processes
- neuroglia
It composes
- anterior ventral horns of lateral horns
- posterior or dorsal horns.

Front 10

White matter in the spinal cord is composed of?

Back 10

-myelinated/unmyelinated fibers
- can run in ascending and descending directions
- can be commissural

Front 11

Posterior Horn takes care of ______ info

Back 11

Sensory

Front 12

Lateral horn takes care of __________ info

Back 12

Autonomic motor -- visceral motor neuron

Front 13

Anterior Horn takes care of ______ info

Back 13

somatic motor

Front 14

How many non-cranial spinal nerves exist.

Back 14

- 31 pairs
- supply all parts of the body except the head and some areas of the neck
- all are mixed nerves: 8 pairs of cervical nerves, 12 pairs of thoracic, 5 pairs of lumbar, 5 pairs of sacral, 1 pair of coccygeal.

Front 15

All spinal nerves have both dorsal and ventral roots. How do these divide and what is their function.

Back 15

Dorsal ramus and ventral ramus. These are found before the info splits into the dorsal and ventral roots.

Dorsal rami: supply the posterior body trunk
Ventral rami: supply the rest of the body trunk and limbs.

Front 16

More specific information on the Dorsal Rami

Back 16

- supplies the posterior body trunk
- each dorsal ramus innervates or receives input from a narrow strip of muscle and skin in line with its emergence point from spinal cord.
- think of painted man

Front 17

Ventral Rami of thoracic nerve

Back 17

wrap forward along with the rib and sit in the intercostal nerve.

Front 18

General info on the ventral rami of nonthoracic spinal nerves

Back 18

- branches profusely and form networks of nerves called plexusus
- major plexuses occur in the cervical, brachial, lumbar, and sacral regions
- within each plexus the fibers of the ventral rami crisscross each other: each branch of plexus contains fibers from several spinal nerves, fibers from each spinal nerve carried to body periphery via several routes.

Front 19

Info on Plexus

Back 19

It is a complex network of the ventral rami of non-thorasic spinal nerves.
- Because so many sort of safe guard essential sensory routes so if one is injured, there are backups.

Front 20

What is the Autonomic Nervous system?

Back 20

system of neurons that innervates smooth and cardiac muscles and gland; involuntary division of PNS.
Used in:
- glands
- cardiac muscle
- smooth muscle.

Front 21

Summary of Nervous system organization

Back 21

- efferent division of PNS
- SNS: innervates skeletal muscles; voluntary PNS division
- ANS: system of neurons that innervates smooth and cardiac muscle and glands; involuntary division of PNS

Front 22

Difference s in what SNS and ANS stimulate

Back 22

SNS: stimulates skeletal muscles
ANS: stimulates cardiac and smooth muscles and some glands.

Front 23

Differences in efferent pathways of SNS and ANS

Back 23

SNS: Cell bodies of motor neurons are in the CSN, their axons extend in spinal nerves to skeletal muscles they serve
ANS: system has set of distinct effectors. Two neuron motor pathways.

The preganglionic neuron is the cell body in the CNS and the postganglionic neuron is in ganglion outside of CNS which will extend to the effector organ.

Front 24

What is similar with both sympathetic and parasympathetic divisions of the ANS

Back 24

Both use 2 neurons
- Both 1st release AcH
- 1 neuron starts in CNS
- Second neuron ends in whatever is being innervated.

Front 25

What is the difference between the sympathetic and parasympathetic branch of ANS

Back 25

- sympathetic: second neuron releases Norepinephrine or epiniphrine, the primary neuron is generally shorter than the second (with the exception of adrenal medulla communication because it just release NT to effect an organ)

Parasympathetic:
- 1st neuron is longer
- AcH is released from both neurons.

Front 26

Only _________ of ANS are myelinated

Back 26

preganglionic cells.

Front 27

What is the purpose of having both a sympathetic an parasympathetic division of ANS

Back 27

The both serve same visceral organs but they cause essentially opposite effects -- dual innervation

Front 28

Parasympathetic Division

Back 28

- "resting and digesting"
- keeps energy use low while maintaining vital functions
- preganglionic fibers: craniosacral orgin; long preganglionic fibers,
- short postganglionif fibers

Front 29

Sympathetic Division

Back 29

- "fight or flight" takes over during stressful or emotional situations
- preganglionic fibers: thoracolumbar origin; short preganglionic fibers, long post ganglionic fibers.
- ganglia are close to the spinal cord.

Front 30

What areas of the body do not use the dual innervation system.

Back 30

Blood Vessels: innervated by sympathetic nerve fibers: sympathetic = constriction = increased blood pressure.
- sweat glands - innervated only by sympathetic nerve fibers
- Salivary glans - innervated by both division but activities not antagonistic
: PS - enzyme rich saliva
: SYM - mucous rich saliva : stress: drymouth.

Front 31

Stress equals which branch of ANS

Back 31

Stress = Sympathetic = Saliva = Scary movie = Fight or flight.

Front 32

How is the adrenal medulla effected by the ANS

Back 32

It is part of the sympathetic ANS and it works as the second neuron being excited by ACH and releasing Epinephrine or NE into the Blood to effect the smooth muscle.

Front 33

Overview of parasympathetic division

Back 33

- long preganglionic axons
- short postganglionic axons
- ganglia very close to or within target organ
- PS endings and effects
- Cranial outflow: effects can be brought on by cranial nerves

Front 34

What is sacral outflow

Back 34

parasympathetic signals which originate from the neurons located in the lateral gray matter of sacral spinal cord segment.

Front 35

Overview of sympathetic division

Back 35

- short preganglionic axons
- long postganglionic axons
- gangila far removed from target organ
- preganglionic fibers arise from cell bodies located in lateral horns of spinal cord segments

Front 36

Examples of sympathetic ganglia

Back 36

- sympathetic chain gangila
- collateral gangila
- Adrenal medulla

Front 37

What does each type of ganglionic neuron target.

Back 37

- sympathetic chain ganglion: visceral effectors in thoracic cavitity, head, body wall, and limbs: CLOSER TO SPINAL CORD
- Collateral ganglia (unpaired) visceral effectors in abdominopelvic cavity: FURTHER FROM SPINAL CORD
- Adrenal medullae: organs and systems throughout the body.

Front 38

What do you call a fiber that releases Ach vs. Epinephrine

Back 38

ACh = cholinergic fiber - always released by preganglionic fibers and effects are always excitatory. Can be release by postganglionic too.
E/NE = adrenergic fiber

Front 39

Overview of ANS: neurotransmitters

Back 39

- each autonomic NT can stimulate activity in some tissue and inhibit activity in others
-particular responses depend on specialization of tissue cells, not the NT themselves
- Responsive tissue cells pocssess one or more of several different receptors for these chemicals.

Front 40

What do cholinergic receptors of ACH do and what are two examples.

Back 40

The bind ACh.
Two examples:
- nicotinic receptors
- muscarinic receptors.

Front 41

What do Nicotinic receptors do;

Back 41

- bind ACh
- all postganlionic neuron receptive regions; hormone producing cells of adrenal medulla
- also in motor end plate of skeletal muscle
- activated by nicoted
- usually excitatory

Front 42

What do Muscarinin receptors do?

Back 42

effect cells of postganglionic parasympatheict fibers.
- different types M1, M2 ...
- activated by muscarine
- Atropine is antagonist.