BS-1 Neuro (part two)

True or false. The Autonomic Nervous System (ANS) is located in both the CNS and PNS

TRUE; but it is considered to be a part of the visceral efferent PNS

What is the main function of the ANS?

HOMEOSTASIS; Coordinates and maintains a steady-state among the visceral organs

What are the two divisions of the ANS?

Sympathetic and Parasympathetic

True or false. The enteric nervous system is NOT a part of the ANS.

FALSE; it is a part of the ANS. It is responsible for the GI system and can operate independently or with the sympathetic/parasympathetic.

Which system is your "fight-or-flight" response?

Sympathetic

The sympathetic system receives innervation from the cells bodies of ____ through ____ which is known as your _________________________

T1-L2; thoracolumbar division

Sympathetic nervous system (fx)

Mobilizes energy stores in times of need

Which system is your "rest and digest" response?

Parasympathetic

Parasympathetic nervous system (fx)

Functions to conserve and restore energy

The parasympathetic system receives innervation from (some) ______________ and part of the ______________ region of the spinal cord. This is called the ____________________ division.

-some cranial nerves

-part of sacral region

-Craniosacral division

Sympathetic PREganglionic fibers

-NT:

-Receptor:

NT: Acetylcholine

Receptor: Cholingeric

Sympathetic POSTganglionic fibers

-NT:

-Receptor:

NT: Norepinephrine

Receptor: Adrenergic

Another term for norepinephrine is:

Noradrenaline

Another term for adrenaline is:

Epinephrine

Parasympathetic PREganglionic and POSTganglionic fibers

-NT:

-Receptor:

NT: Acetylcholine

Receptor: Cholingeric

Are these findings due to parasympathetic or sympathetic innervation: increased HR, dilated pupils, bronchodilation, dry mouth

Sympathetic

Are these findings due to parasympathetic or sympathetic innervation: decreased HR, constricted pupils, bronchoconstriction, increased secretions of mucous

Parasympathetic

True or false. The Parasympathetic ANS is associated with cholinergic receptors.

TRUE

True or false. Adrenergic receptors are ONLY found in the CNS.

FALSE; they are found in different tissues in our bodies

True or false. The Sympathetic ANS is associated with adrenergic receptors.

TRUE

What are the two types of adrenergic receptors?

-alpha (a) adrenergic
-beta (b) adrenergic

What class of NTs activate adrenergic receptors?

Catecholamines

What are examples of catecholamines?

-Norepinephrine/NE (noradrenaline )

-Epinephrine/Epi (adrenaline)

What type of signaling pathway is activated when an adrenergic receptor is agonized (activated)?

Intracellular (GPCR); this is known as METABOTROPIC

What are the different types of a-adrenergic receptors and what are they associated with (2)?

-a1 (most common): associated w/ excitation or stimulation

-a2: associated with relaxation or inhibition

Agonizing an a1 receptor causes: (2)

-Vasoconstriction (of blood vessels)

-Smooth muscle contraction (urinary structures=retention of urine)

Agonizing an a2 receptor causes: (2)

-The inhibition/release of NE (norepinephrine)

Agonizing a B1 receptor causes: (3)

-Increases HR

-Increases contractility

-Causes the release of renin from the kidney which causes an increase in blood volume

(tip: beta blockers act on heart, number 1 because you have 1 heart)

Agonizing a B2 receptor causes: (3)

-Vasodilation

-Relaxation of smooth muscles found in: uterine, bronchus, and bronchioles (lung)

-Some lipolysis (breakdown of fat)

(tip: number 2 bc you have two lungs, and #2 causes relaxation)

Agonizing a B3 receptor causes: (2)

-Mediation of lipolysis
-Thermogenesis

(Brianna said not really clinically significant)

What are the 2 types of cholinergic receptors?

nicotinic and muscarinic

What NT activates cholinergic receptors?

Acetylcholine

Cholinergic receptors are responsible for muscle (contraction/inhibition) _____________; and are involved in memory, _____________, and arousal

Muscle contraction; involved in memory, learning

How do nicotinic receptors work?

1. When activated they directly open ion channels this makes these receptors IONOTROPIC

2. This stimulates the release of other NTs at the post-synaptic neuron which then causes:

3. Skeletal muscle to CONTRACT

How do muscarinic receptors work and how are they classified?

They activate intracellular signaling pathways (GPCR- just like adrenergic receptors);

classified as: METABOTROPIC

Agonizing a muscarinic receptor causes: (4)

-INCREASE gland secretion

-Decrease HR

-Pupil constriction

-SMOOTH muscle contraction (some)

There are two types of nicotinic receptors: muscle specific (Nm) and nerve specific (Nn). When agonized, what do each cause and where are these receptors found?

Nm: SKELETAL muscle contraction; the end plate of skeletal muscle

Nn: Secretion of Epinephrine, control ANS; Autonomic ganglia, Adrenal medulla

___________ is a protective and complex phenomenon made up of dynamic interactions among: physical, cognitive, spiritual, emotional, and environmental factors.

Pain

Pain threshold is the (lowest/highest)____________ intensity of pain that a person can (handle/recognize) _______________.

LOWEST; RECOGNIZE

True or False. Intense pain at one location may increase the threshold in another location.

TRUE; this means that experiencing intense pain in one area of the body can make you less sensitive to pain in another area

Pain tolerance is the ______________ intensity of pain that an individual can ______________.

HIGHEST; ENDURE

True or false. Pain tolerance is very individualized and varies greatly among people and in the same person over time.

TRUE

What are nociceptors and what are the two main types?

They are pain receptors:

1. A-delta fibers

2. C fibers (most numerous)

1. A-delta fibers

-Size:

-Myelinated or not:

-How it transmits pain (3):

-Spinal reflex yes or no:

-Larger

-Myelinated

-Transmit fast, sharp, well-localized pain sensations

-YES causes a spinal reflex

1. C fibers

-Size:

-Myelinated or not:

-How it transmits pain (5):

-Spinal reflex yes or no:

-Smaller

-Unmyelinated

-Transmits slow, poorly localized, dull, aching, or burning sensations

-NO reflex

Which type of fibers transmit sharp, well localized pain sensations?

A-delta fibers

Which type of fibers transmit aching or burning sensations?

C fibers

What are nociceptors stimulated by? (4)

-Mechanical pressure or distortion
-Thermal extremes
-Chemicals
-Inflammatory mediators: bradykinin, histamine, leukotrienes, protaglandins

What are the 4 steps in nociception?

1. Transduction
2. Transmission
3. Perception
4. Modulation

What occurs in step 1. transduction (2)?

1. nociceptors are activated by painful stimuli
2. ion channels open up, AP is reached, and electrical impulses are generated

What is the shortened/simple version of what happens in step 2. transmission (4)?

-signal goes to dorsal horn of spinal cord

-crosses over to the spinothalamic tracts w/in the spinal cord

-then signal goes up to the thalamus

-thalamus tells the signal to go to different parts of the brain

What occurs in transmission- long version (5)?

1. The impulse travels through the axons of nociceptors to the

DORSAL horn of the spinal cord

2. Nociceptor axons synapse with the 2nd order neuron there

3. 2nd order neuron CROSSES the midline of the spinal cord and ascend through the spinothalamic tracts (lateral: pain and temp, and anterior: vague touch)

4. 2nd order neuron synapses with the 3rd order neuron in the THALAMUS (relay center)

5. Signal are then projected to the limbic system, frontal cortex, and primary sensory cortex.

What occurs in step. 3 perception (2)?

1. There is a conscious awareness of pain once the signal is projected to the different destinations in the brain

2. This is influenced by genetics, cultural preferences, gender roles, age, health, past pain experiences

When pain signals reach the somatosensory cortex what is perceived? (3)

-Character (of pain)
-Location (of pain)
-Intensity (of pain)

When pain signals reach the limbic system and reticular formation what is the response? (2)

-emotional response to pain

-conditioned avoidance behaviors

When pain signals reach the cerebral cortex what is the response? (2)

-modulation of perception

-learned behavior concerning pain

__________________ of pain is the processes by which the perception of pain is altered or influenced by various factors including: excitatory and inhibitory neurotransmitters

modulation (step 4)

What do excitatory NT do in modulation?

Increase the likelihood that pain signals will be transmitted; cause depolarization

What are the main excitatory NT? (8)

1. Histamine

2. Bradykinin

3. Glutamate

4. Prostaglandin

5. Substance P

6. Calcitonin

7. Norepinephrine (peripheral nerves ONLY +)

8. Serotonin (peripheral nerves ONLY +)

What do inhibitory NT do in modulation?

Reduce the transmission of pain signals and help modulate the pain experience

What are the main inhibitory NT (5)

1. Gamma-aminobutyric acid (GABA)

2. Glycine

3. Endogenous opioids

3. Norepinephrine (CNS only -)

4. Serotonin (CNS only -)

Which two NT cause both excitatory and inhibitory effects depending on the location that they are released?

-Norepinephrine
-Serotonin

True or false. There are different types of opioid receptors that are widely distributed throughout the body

TRUE; the types are: mu, kappa, and delta (what a sorority girly pop)

What are three main classification of endogenous opioids?

1. Endorphins
2. Enkephalins
3. Dynorphins

1. Endorphins are made in the ____________ and bind to ____ receptors

BRAIN; mu

2. Enkephalins are the _________ prevalent and bind to _________ receptors

MOST; delta

3. Dinorphins are the _________ potent and bind to __________ receptors

MOST; kappa

What are the functions of endogenous opioids (5) ?

-Pain modulation

-Mood regulation

-Cardiovascular protection

-Respiratory depression

-Decrease GI motility

There are different paths that pain modulation can occur in. Name the 3 paths mentioned in class.

1. Descending inhibitory pathways (from the CNS)
2. Segmental pain inhibition
3. Gate control theory

How does pain modulation occur in the descending inhibitory pathway?

-Neurons from the CNS release NTs such as GABA (-) and serotonin (-).

-These NT cause an inhibitory affect once they reach the dorsal horn of the spinal cord.

-This causes a DECREASE in pain! (woohoo!)

How does pain modulation occur in the segmental pain inhibition pathway?

-When A-beta fibers (which carry non-painful sensation such as vibratory signals) are stimulated, it causes the stimulation of inhibitory INTERNEURONS

(this is a process that is similar to "gate control")

How does pain modulation occur in the gate theory control?

-A-delta and C fibers respond to painful stimuli

-Nociceptive transmission "open" the gate

-Stimuli from non painful transmission such as touch, vibration, etc. "close" or partially close the gate which inhibits the transmission of pain signals

-Emotional state, attention, and medications also influence the "gate"

What is the difference between segmental pain inhibition and gate theory control?

Segmental pain inhibition focuses specifically on the local interactions between sensory fibers and interneurons in the spinal cord.

Gate control theory encompasses a broader understanding of how pain perception is influenced by various factors

True or false. Children ages 5-18, have a lower pain threshold (are more sensitive to pain) than adults.

TRUE; ofccc lil bbys are so fragile

The nociceptor (pain) system is functional by _____ to _____ weeks of gestation (in the womb)

20-24 weeks of development is needed for our pain system to start working!

Babies can have different expressions of pain. A baby is noted to be in pain through: (4)

-their facial expressions
-if there crying
-their body movements
-their inconsolability

True or false. Pain tolerance decreases (more sensitive) as you get older.

TRUE

As one ages, alteration in the _________________ of drugs and ____________ occurs

METABOLISM; metabolites

Why can pain threshold increase in older people (3)?

-Peripheral neuropathies (decreases the sensation of pain)

-Skin thickness changes (thick skin can decrease pain reception)

-Cognitive impairment (can't perceive pain)

What race gets under treated for pain.

Black people. DON'T BE BIAS WHEN TREATING PAIN.