physiology afferent and efferent

The efferent output of the brain and spinal cord is to control....

all the effectors of the body

What one thing does the somatic nervous system control?

Skeletal muscle

What are the cells that line your stomach called?

enterocytes

interoceptors do what?

-internal receptors

-visceral senses (deep)

ex: nociceptors sense pain in stomach

exteroceptors do what?

sense external environment; general senses are located in your skin

Proprioceptors do what?

located in muscles/joints/tendons and sense position of muscle

How many pairs of cranial nerves are there?

12

How many pairs of spinal nerves are there?

31

31

important cranial nerves: (what is each for?)

1. olfactory

2. optic

3. vagus

4. vestibulocochlear

1. smell

2. vision

3. heart/lungs/bronchi/gastro

4. hearing & equilibrium

3 types of cartilage;

most abundant? least abundant? strongest?

1. Highland cartilage -most abundant

2. Fibro cartilage -least abundant & strongest

3. Elastic cartilage

What are the anatomical components of the peripheral nervous system (PNS)

cranial and spinal nerves

What is the functional organization of the PNS? In other words, can you schematically explain the organization of the efferent division and the afferent division of the PNS?

two divisions of PNS: afferent & efferent

Afferent: sensory innervation; somatosensory, special sensory, and visceral innervation

Efferent: somatic and autonomic innervation

*Autonomic innervation includes cardiac, smooth muscle, glandular, and adipose innervation. The autonomic system also breaks down into the sympathetic, parasympathetic, and enteric nervous systems.

Sensory information enters the afferent division of the PNS. What are exteroceptors?

sensory receptors that receive external stimuli for both special and somatic senses, and send the sensory information to the CNS

What are proprioceptors and what type of information do they send to the CNS?

sensors that provide information about joint angle, muscle length, and muscle tension, which is integrated to give information about the position of the limb in space

What are interoceptors and what type of information do they send to the CNS?

Interoceptors are receptors that receive stimuli of internal organs

(visceral senses)

How many pairs of cranial nerves are there?

Do all cranial nerves contain both sensory and motor nerve fibers?

12;

some are mixed, but not all

How many pairs of spinal nerves are there?

31

What are the different types of intervertebral disc abnormalities that can occur and how can these issues relate to spinal stenosis?

Intervertebral disc deterioration and herniation;

lead to spinal stenosis by causing a narrowing of the open spaces within your spine. This can put pressure on your spinal cord and spinal nerves

What is a ventral root composed of?

What is a dorsal root composed of?

ventral root = motor neurons

dorsal root = sensory neurons

What is a dorsal root ganglion composed of?

contains the cell bodies of unipolar neurons

What is a ventral ramus?

What is a dorsal ramus?

ventral ramus = anterior division of a spinal nerve

dorsal ramus = posterior division of a spinal nerve.

What are the sympathetic chain ganglia?

paired bundles of nerve fibers, and aggregations of nerve cell bodies, that run from the base of the skull to the coccyx. They are part of the autonomic nervous system.

two components of the PNS combine to form a spinal nerve?

Ventral and dorsal roots combine to form a spinal nerve

What are the three neurons involved in the spinal reflex arc and how do they communicate with one another?

afferent neurons, interneurons and motor neurons;

-communicate through the neurotransmitters that are released in the synaptic clefts between them.

What are mechanoreceptors and what are some general examples?

respond to mechanical stimuli;

Ex: tactile receptors, baroreceptors and proprioceptors.

What are the three examples of tactile receptors in the skin and what do they detect?

Pacinian corpuscles: sense deep touch

Meissner's corpuscles: sense light touch

Merkel cells: sense light touch

ipsilateral vs contralateral

ipsilateral: senses converge at the level of the brain stem

contralateral: senses converge at the level of the spinal cord

1. Which receptors would inform you of an ice cube that was just placed on your arm?

2. Which receptors would inform you of the taste of a cup of coffee?

3. Which receptors would inform you of the pain of stepping on a nail?

1. Thermoreceptors

2. Chemoreceptors

3. Nociceptors and mechanoreceptors

Are nociceptors tonic or phasic receptors?

Nociceptors are tonic

tonic vs phasic

tonic : slowly adapting

phasic: quickly adapting

Are odorant receptors phasic or tonic?

phasic

The receptor portion of tactile receptors (e.g., Meissner's and Pacinian corpuscles) is a modification of what portion of the neuron?

The receptor portion of one of these sensory neurons is a modification of a dendrite

What happens to the membrane of the receptor as a result of receiving a stimulus?

ion channels open, allowing sodium to enter, leading to the generation of the first action potential at the initial segment of the neuron.

If you had a lesion on your arm, what medications could you take to reduce the activity of prostaglandins, histamine and substance P?

reduce activity of prostaglandins: NSAID (e.g., ibuprofen, aspirin);

reduce activity of histamine: antihistamine (e.g., Benadryl);

reduce activity of substance P: capsaicin

What do opiates mimic?

Heroin and prescription opioids chemically resemble the brain's natural opioids (i.e., endorphins).

Does nociceptive information travel to the brain contralaterally or ipsilaterally?

contralaterally

The phenomenon of referred pain is thought to exist as the result of "crosstalk" between neurons. Where is it believed that this cross-talk occurs?

spinal cord gray matter or dorsal root ganglia

explain how an individual can experience pain in the arm when they are having chest pain due to a heart attack?

When a person is having a heart attack, the pain fibers in the heart and hand go to the spinal cord and they converge (cross-talk). The pain fibers from the heart can induce action potentials in the pain fiber coming from the arm

What are the five different types of special senses?

Taste (gustation), smell (olfaction), sight (vision), hearing (audition) and balance/equilibrium (equilibrioception)

How many cells are involved in the peripheral processing of olfactory information?

In what cell are action potentials generated?

2;

generated in the primary bipolar sensory neuron and the secondary sensory neuron

Thinking anatomically, can you explain why smell is the only special sense that does not enter the brain by relaying through the thalamus?

The primary neurons enter the brain through tiny holes in the floor of the cranium and synapse with the secondary neurons in the olfactory bulbs at the base of the brain

what are the tastant(s) for each of the 5 tastes

bitter: coffee, beer, unsweetened cocoa, earwax, etc.

sweet: monosaccharides

umami: glutamate

sour: proton

salty: sodium

Why isn't "spicy" one of the 5 tastes?

Our bodies detect spice using a completely different system than the one for taste. The nerve that sends touch, pain, and temperature feelings from your face to your brain, interprets it

Many individuals who have experienced COVID-19 symptoms have been said to have "lost their sense of taste". Is this a true statement?

Technically, no. Many patients notice a loss of their sense of smell. However, because smell is necessary to taste flavor, these individuals are no longer able to discern flavors.

How many cells are involved in the peripheral processing of gustatory information?

2 -taste receptor cell and the bipolar sensory neuron

In what cell are action potentials generated?

bipolar sensory neuron