Anat Chapter 14

Question 1

What are the two branches of the Peripheral nervous system?

Answer 1

The somatic nervous system (SNS) and the Autonomic nervous system (ANS)

SA

Question 2

what is the somatic nervous system

Answer 2

system responsible for voluntary muscle movements and somatic reflex arcs
-it is mostly voluntary

Question 3

What is the autonomic nervous system? (ANS)

Answer 3

Almost all effectors are visceral, helps maintain a stable internal environment
-Ex: regulation of heart rate, blood vessel diameter, pupil size, body temperature, increase/decrease stomach secretions

Question 4

the ANS VS SNS have three distinct differences. what are these?

Answer 4

-effector organ
-efferent pathways and ganglia
-Neurotransmitters effects

EEN

Question 5

ANS VS SNS effector organ

Answer 5

SNS- skeletal muscle tissue
ANS- cardiac muscle, smooth muscle (gut) and glands

Question 6

ANS vs SNS efferent pathways and ganglia

Answer 6

SNS
-single neuron extends from CNS to effector
-Motor neuron cell bodies located in CNS, axons in PNS extend to skeletal muscle
ANS
-consists of two neuron chain to reach effector
-Preganglionic neuron: cell body in CNS, axon synapses with second motor neuron
-Postgangionic neuron: cell body is outside the CNS, axon extends to effector organ
-Ganglia: site of synapse between the preganglionic neuron and postganglionic neuron.

Question 7

ANS vs SNS Neurotransmitters effects

Answer 7

SNS
-all release acetylcholine at synapses
-effect is always excitatory
ANS
-release norepinephrine or acetylcholine
-effect can be excitatory or inhibitory

Question 8

what are the two divisions of ANS:

Answer 8

The parasympathetic vs sympathetic

Question 9

the parasympathetic division

Answer 9

-“rest and digest”
-directs “housekeeping” activities concerning digestion and waste elimination, heart rate and blood pressure, airway diameter, pupil diameter, reproduction

Question 10

where is the origin of fiber for the Parasympathetic?

Answer 10

-brain and spinal cord
-preganglionic fibers are long, postganglionic fibers are short

Question 11

where is the location of the ganglia for the parasympathetic division?

Answer 11

in or near the effector organ

Question 12

the sympathetic division

Answer 12

• “fight or flight”
  -Activated when we are excited/scared/embarrassed

Question 13

The sympathetic division- origin of fibers?

Answer 13

thoracolumbar region of spinal cord (T1-L2)
-preganglionic fibers are short
-postganglionic fibers are long
-cell bodies of this division form lateral horns of spinal cord

Question 14

where is the location of Ganglia at the sympathetic division?

Answer 14

close to the spinal cord

Question 15

why is the sympathetic division more complex than the parasympathetic division?

Answer 15

-innervaes smooth muscle, cardiac muscle, and glands in body cavities (innervates more parts of body)
-also innervates smooth muscle and glands in superficial regions (effects circulation)
-sweat glands, arrestor pili, smooth muscle in blood vessel was

Question 16

explain the anatomy of the sympathetic division?

Answer 16

-so the preganglionic fibers leaving the spinal cord form the sympathetic trunk (the trunk allows fibers to synapse with one another)
-the sympathetic trunk allows preganglionic axons to travel to spinal nerves that are higher or lower than were they originate
-sympathetic trunk is located on both sides of the spinal cord

Question 17

what is the pathway to the sympathetic trunk?

Answer 17

first the preganglionic fibers exists the spinal cord. the fibers pass though the white ramps communicans. the white ramus communicans guide the preganglionic fiber to the sympathetic trunk. the fibers enter the sympathetic trunk ganglion. the sympathetic trunk ganglion is where the preganglionic fiber synapse with the postganglionic fiber

Question 18

a trunk ganglion, preganglionic and postganglionic fibers can form synapses 1 of 3 ways. explain them

Answer 18

• same level
  -higher or lower level
  -distant collateral ganglion in abdomen and pelvis

Question 19

Pathways with synapses in trunk ganglia

Answer 19

-If synapse forms in trunk ganglia postganglionic fibers travel through gray rami communicans to enter ventral or dorsal ramps of adjoining spinal nerve
-gray rami communicans: carry postganglionic fibers from sympathetic trunk ganglion to periphery
-from here travel to effectors

Question 20

pathways to the head

Answer 20

-preganglionic fibers emerge from** T1-T4, synapse with postganglionic fibers at superior cervical ganglion** of the sympathetic trunk
-functions: serves skin and blood vessels of head, stimulate dilator muscles of eyes, inhibits nasal and salivary glands, innervates muscle to upper eyelids, sends branches to heart

Question 21

pathway to the thorax

Answer 21

-pregangion fibers emerge from T1-T6
-most postganglionic axons pass through cardaic, pulmonary, and esophageal plexuses to effector organ

Question 22

pathways with synapses in collateral ganglia

Answer 22

-preganglionic fibers from T5-L2 synapse in collateral ganglia
form splanchnic nerves:
* greater splanchnic nerve, lesser splanchnic nerve, least splanchnic nerves
* -lumbar splanchnic nerves and sacral splanchnic nerves
* -function: serves abdominal viscera

Question 23

pathway to the abdomen

Answer 23

-fibers T5-L2 innervate abdomen
-function: serve the stomach, most of intestines, liver, spleen, and kidneys

Question 24

pathways to the Pelvis

Answer 24

-fibers T10-L2 innervate pelvis
-function: serves the bladder, reproductive organs, distal half of large intestine

Question 25

what are the 5 components of the Visceral reflex arcs?

Answer 25

1. receptor in viscera 2. sensory neurons -non encapsulated nerve endins -functions: send sensory information about changes in chemical composition, stretch, temperature and irritation of viscera 3. integration center 4. motor neurons -preganglionic and postganglionic neurons 5. visceral effector -smooth muscle cardiac muscle and glands RSIMV

Question 26

ANS neurotransmistters

Answer 26

Acetylcholine (ACh) and Norepinephrine (NE)

Question 27

Acetylcholine (ACh)

Answer 27

-effect in not entirely excitatory or inhibitory, depends on receptor it binds -released by **cholinergic fibers** at: 1. All ANS preganglionic axons 2. All Parasympathetic postganglionic axons at synapse with effector

Question 28

cholinergic receptors that bind Acetylcholine

Answer 28

1. nicotinic receptor -found on: all postganglionic neurons (sympathetic and parasympathetic), hormone producing cells of the adrenal medulla, sarcolemma of skelatal muscel cells -effect: binding of ACh here is ALWAYS **stimulatory ** 2. Muscarinic receptors -found on: all parasympathetic effectors and some sympathetic effectors -effect: binding of AcH here is **stimulatory or inhibitory ** -ex:binding of ACh to muscarinic receptors of heart is inhibitory -ex: Binding of ACh to muscarinic receptors of smooth muscle of gastrointestinal tract is stimulatory

Question 29

Norepinephrine (NE)

Answer 29

-effect is not entirely inhibitory or excitatory, depends on receptor it binds -released by **adrenergic fibers **at: 1. Sympathetic postganglionic axons

Question 30

Adrenergic receptors that bind Norepinephrine

Answer 30

1. Alpha receptors -locations: all sympathetic target organs 2. Beta receptors -Locations: heart, adipose tissue, kidneys, lungs, blood vessels * binding of NE or epinephrine can be stimulatory or inhibitory * Ex: NE binding at beta receptor of heart increases activity * Ex: Epinephrine binding at beta receptors of bronchioles causes dilation

Question 31

effects of the sympathetic and Parasympathetic divsion

Answer 31

* most organs have dual innervation * Symathetic and parasympathetic divisions innervate organs-both send impulses to organ simultaneously

Question 32

Antagonistic interactions of the divisions

Answer 32

* divisions have opposite effects (if one increases activity of organ the other decrease) * this is determined by which of the two division is sending more impulses

Question 33

vasomotor (sympathetic tone)

Answer 33

* continuous partial constriction of blood vessels * sympathetic fibers supply blood vessels and control blood vessels diameter * if blood pressure is low- vasomotor fibers fire more rapidly -effect: muscle contracts, blood vessels contrict (blood pressure increase) * if blood pressure is high, vasomotor fibers fire less rapidly -effect: muscle relaxes, blood vessels dilate (blood pressure decrease)

Question 34

Parasympathetic tone

Answer 34

* present mostly in cardiac muscle tissue, smooth muscle tissue of digestive and urinary organs * effect: slows heart rate, maintains normal acitvity of digestive and urinary organs * sympathetic division can override parasympathetic tone

Question 35

unique roles of the sympathetic division

Answer 35

1. thermoregulatory response to heat -effects: -A) blood vessels dialte in response to heat, constrict in response to cold -B) Sweat glands activated in response to heat 2. Renin release from kidneys -effects: increases blood pressure 3. Metabolic changes -effects: -A) increases metabolic rate of cells -B) raises blood glucose levels -C) Mobilizes fats used fuel use

Question 36

Parasympathetic divsion exerts...

Answer 36

-highly localized, short lived control -How? 1. one preganglionic neuron synapses with one (or few) postganglionic neurons 2. All Parasympathetic fibers release ACh, quickly broken down by acetylcholinesterase

Question 37

Sympathetic division exerts...

Answer 37

-diffuse, long lasting control -How? 1. Preganglionic neurons synapse with multiple postganglionic neurons 2. NE and epinephrine prolong effects of sympathetic division activation

Question 38

Hypothalamic control of the autonomic nervous system

Answer 38

* the hypothalamus controls most visceral functions 1. Anterior hypothalamic areas oversee parasympathetic division 2. Posterior hypothalamic areas oversee sympathetic division -effects: coordinates heart acitvity, blood pressure, body temperature, water balance, endocrine activity -reminder: limbic system relays output through hypothalamus -emotional response to fear, danger, and stress activate sympathetic division

Question 39

hypertension

Answer 39

* high blood pressue * caused by: overactive sympathetic vasoconstrictor response * effect: heart must work harder to circulate blood through narrow blood vessels * future problems: heart disease, enlarged arteries, kidney failure * treatment: adrenergic receptor blocking drugs

Question 40

raynauds disease

Answer 40

* caused by: Exaggerated vasoconstriction response due to cold or emotional stress * Effect: skin of fingers and toes becomes pale * skin can eventually become cyanotic, painfull * severirty can be minimal or more extreme

Question 41

Autonomic dysreflexia

Answer 41

* affects individuals who are quadriplegic or have spinal cord injuries above T6 * caused by: uncontrolled acitvation of autonomic neurons -usually triggered by some type of pain stimulus to skin or overfilled visceral organ * effect: arterial blood pressure skyrockets -can rupture blood vessels in brain, causing stroke -symptons: headache, flushed face, sweating above injury, cold/clammy skin below injury