BIO201 Lecture Exam 5 (ch. 13, 14, & 15)

Parasympathetic PREganglionic neuron (ANS)

longer; located from the craniosacral region (brain stem → sacral region of spinal cord)

Sympathetic PREganglionic neuron (ANS)

shorter; thoracolumbar region ( #12 thoracic → the first 2 lumbar segments of the spinal cord

Parasympathetic POSTganglionic neuron (ANS)

shorter; neurotransmitter @ effector = Acetylcholine

Sympathetic POSTganglionic neuron (ANS)

longer; neurotransmitter @ effector = Norepinephrine

Epinephrine (hormone) and norepinephrine (hormone and neurotransmitter) bind to

Adrenergic receptors (receptor on the heart = Beta 1)

Beta Blocker →

causes decreased heart rate and can be used to treat hypertension

ACh binds to

muscarinic (seen on heart following postganglionic neuron) and nicotinic (seen on postganglionic neuron) receptors

nicotinic is always

excitatory

Alpha 1 & Beta 1

generally “excite things”

Alpha 2 & Beta 2

generally “relax things” → more inhibitory

Alpha 1 receptor example =

radial muscle of pupil (pupil dilation)

Beta 1 receptors example =

found on the pacemaker cells of the heart; firing action potentials to increase contractility and heart rate

Beta 2 receptors example =

bronchodilation (opens airways) and some vasodilation of BV in smooth muscle

Alpha 2 receptors example =

__inhibits__ insulin secretion from pancreas

I Olfactory

**ONLY sensory** function: sense of smell; **special**  

II Optic

**ONLY sensory** function: transmitting visual information; **special** 

III Oculomotor

* Somatic **motor** function = Innervation (to arouse or stimulate) to the upper eyelid & Innervation of the eye muscles that allow for visual tracking and gaze fixation
* Autonomic **motor** function = Innervation to the pupil and lens

IV Trochlear

ONLY somatic **motor** function = allows for lift the eyes so you can look down and gaze side to side

V Trigeminal

* **sensory** function = touch, pain, and temperature; **somatic**
* somatic **motor** function = elevation, depression, protrusion, retraction, and side to side movement (chewing food)

VI Abducens

ONLY somatic **motor** function = innervates the lateral rectus muscle, an extraocular muscles of the eye, which is responsible for the abduction of the eyes on the same side

VII Facial

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* **sensory** function = taste on anterior tongue; **special**  
* somatic **motor** function = controls facial movement and expression
* autonomic **motor** function = producing tears and saliva 

VIII Vestibulocochlear

* **sensory** function = hearing; **special & equilibrium**
* autonomic **motor** function = motor adjustment to loud sounds specifically 

IX Glossopharyngeal

* **sensory** function = taste on posterior tongue (**special**) and sense pain in your throat (**somatic**) 
* somatic **motor** function = aids in raising throat for swallowing; elevating the pharynx and larynx
* autonomic **motor** function = controls salvation; aids in action of swallowing  

X Vagus

* **sensory** function = minor role in taste sensation (**special**); involved with touch, pain, and temperature (**visceral**)  
* somatic **motor** function = helps muscle involved with creating sound/speaking and swallowing
* autonomic **motor** function = promotes digestion, slows down heart rate, and reduces blood pressure 

XI Accessory

ONLY somatic **motor** function = movement of the sternocleidomastoid and trapezius muscles; head and shoulder movement (shrugging shoulders, tilting and rotating head)

XII Hypoglossal

ONLY somatic **motor** function = protrusion, retraction, and side-to-side movement of tongue, as well as shaping tongue for speech and swallowing 

Special senses include…

vision, hearing, equilibrium, smell, and taste

Which type of neurons enter the spinal cord via the dorsal root?

sensory neurons

What cell structure would you find in a dorsal root ganglion?

 cell bodies of primary sensory neurons

Which type of neurons exit the spinal cord via the anterior root?

sympathetic preganglionic neurons

Define reflex

An involuntary and nearly instantaneous movement in response to a stimulus

Name the 5 components of a reflex are.

sensor, sensory neuron, interneuron, motor neuron, and muscle

Which reflex is implemented to help avoid overstretching of a muscle?

Stretch aka Myotatic Reflex

Which reflex is implemented to avoid tendon damage in the case of a muscle that has been too forcefully contracted?

The Golgi tendon reflex

Which reflex would be used to assess your patient’s response to deep pain stimuli?

Many of the different reflexes can assess deep pain stimuli some examples are: tendon and stretch reflexes. 

Which reflex is considered contralateral?

The crossed extensor reflex

Give an example of a diagnostic reflex.

Patellar stretch reflex (tapping the patellar ligament causes a stretch on the quadriceps muscles resulting in classic knee jerk reflex)

What would the lack of this reflex indicate?

damage to sensory or motor neurons in these regions, or a spinal cord injury in the lumbar region

Which plexus supplies the anterolateral abdominal wall and part of the lower limbs?

lumbar plexus

Which plexus contains the phrenic nerve?

**cervical plexus**

What does the phrenic nerve do?

essential in breathing; provides motor innervation to the diaphragm and work in conjunction with secondary respiratory muscles

Which plexus supplies the buttocks and lower limbs?

sacral plexus/lumbosacral plexus

What portions of the body are served by the brachial plexus?

provides somatic motor and sensory innervation to the upper extremity, including the scapular region; axilla, arm, forearm, and hand

Which nerve or nerve branch may be impaired if your patient is displaying “foot drop”?

 peroneal nerve

What is your patient’s main problem if his/her spinal cord is transected above the level of C3?

can affect the muscles involved with breathing; permanent loss of central control of motor, sensory, and autonomic functions below the injured segment

Does nervous tissue repair itself? Explain your answer.

No, they **cannot** repair themselves, because mature neurons are amitotic (can’t go under mitosis). Only olfactory neurons can repair itself fully. If the soma is intact, limited regeneration can occur in the PNS. In the CNS, little to no regeneration occurs to damaged neurons.

Which cranial nerve does the dentist inject?

Cranial Nerve V (Trigeminal nerve)

Which cranial nerve moves the tongue?

Hypoglossal Nerve

Which 3 cranial nerves contribute to eye movement?

Cranial nerves III (CNIII) (oculomotor), IV (trochlear), and VI (abducens)

Which cranial nerve contributes both to hearing and balance?

vestibulocochlear nerve

If your facial surgeon makes a mistake and nicks your facial nerve, what will the main effect be on you?

Facial paralysis → the inability to move the muscles that control smiling, blinking, and other facial movements.

Give an example of a cranial nerve reflex.

Pupillary light reflex, which is when pupils decrease in diameter when exposed to light.

 Name as many sensory receptors that you can think of…

* mechanoreceptors
* thermoreceptors
* nociceptors
* chemoreceptors

What is the purpose of a nociceptor?

initiate the sensation of pain

Where is pain sensed?

in the sensory receptors in our skin

Where is pain perceived?

to the spinal cord, brainstem, and cerebral cortex 

Where is pain perceived?

to the spinal cord, brainstem, and cerebral cortex 

What is proprioception?

perception or awareness of the position and movement of the body.

Name 3 proprioceptors.

1. neuromuscular spindles
2. Golgi tendon organ
3. joint kinesthetic receptor

Phrenic nerve

* muscle that is innervated = diaphragm 
* Breathing; only nerve in your nervous system that provides motor function to your diaphragm. It sends signals that cause your diaphragm to expand and contract (These movements allow your lungs to inhale and exhale air)

Results of phrenic nerve not functioning properly =

Breathing problems…

* shortness of breath
* → a paralyzed diaphragm 
* those with severe damage may need a mechanical ventilator in order for them to breath

Musculocutaneous nerve

* muscle that is innervated = the __three__ muscles of the anterior compartment of the arm: the __coracobrachialis__, __biceps brachii__, and __brachialis muscles__
* allows for arm flexion 

Results of musculocutaneous nerve not functioning properly =

* weakness in elbow flexion or shoulder flexion
* atrophy of the biceps brachii
* pain or paresthesia at the lateral forearm

Ulnar nerve

* muscle that is innervated = __Flexor carpi ulnaris__ and __flexor digitorum profundus__. It also innervates the intrinsic muscles of the hand including: the __palmaris brevis__, __lumbricals__, __hypothenar__ and __interosseous__ muscles.
* provides **motor** innervation to part of the forearm and majority of the hand and supplies sensory cutaneous innervation to the medial forearm, medial wrist, and medial one and one-half digit

Results of ulnar nerve not functioning properly =

* pain
* numbness
* tingling in the forearm and the fourth and fifth fingers. 
* In severe cases, ulnar nerve entrapment can cause weakness in the hand and loss of muscle mass.

Median nerve =

* muscle that is innervated = flexor muscles of the forearm and hand, as well as those muscles responsible for flexion, abduction, opposition, and extension of the thumb.
* Provides motor innervation to the flexor muscles of the forearm and hand, as well as those muscles responsible for flexion, abduction, opposition, and extension of the thumb

Results of median nerve not functioning properly =

* Numbness
* Pain
* → motor, sensory, and vasomotor loss

Radial nerve

* muscle that is innervated = triceps brachii, anconeus, and brachioradialis muscles
* helps you move your elbow, wrist, hand and fingers

Results of radial nerve not functioning properly =

* sharp burning pain 
* Partial or complete loss of feeling in the hand
* Partial or complete loss of wrist or hand movement

Obturator nerve

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* adductor longus, adductor brevis, and gracilis muscles
* provides motor (muscle movement) and sensory (sensation) to your inner thigh
* helps with extending your leg @ the knee

Results of obturator nerve not functioning properly =

* muscle pain & weakness (when you extend your leg or move it from side to side)
* leg cramps 

Femoral nerve

* the flexors of the hip (pectineus, iliacus, sartorius) and the extensors of the knee (quadriceps femoris).
* motor and sensory processing in the lower limbs.
* It controls the major hip flexor muscles, as well as knee extension muscles.

Results of femoral nerve not functioning properly =

* nerve pain that radiates from your back and hip to your legs
* partial or complete loss of movement or sensation, resulting in some degree of permanent disability

Sciatic nerve

* long head of the biceps femoris muscle, superficial to adductor magnus and short head of biceps femoris muscle, and laterally to semitendinosus and semimembranosus muscles
* Motor function: Helps the muscles in your leg and feet move. Sensory function: Helps you feel sensations in your legs.

Results of sciatic nerve not functioning properly =

* “foot drop”
* weakness
* numbness 
* permanent nerve damage → resulting in a loss of feeling in the affected legs

Tibial nerve

* muscles of the lower leg and foot… triceps surae (the two headed gastocnemius and soleus), plantaris, Popliteus, tibialis posterior, flexor digitorum longus and flexor hallucis longus
* provides motor and sensory innervation to most of the posterior leg and foot.

Results of tibial nerve not functioning properly =

Tibial nerve dysfunction… numbness, pain, tingling, and weakness of the knee or foot

Common Peroneal/Fibular nerve

* the short head of the biceps femoris muscle (part of the hamstring muscles, which flex at the knee).
* innervating the muscles that compose the anterior and lateral muscular compartments of the lower extremity.

Results of the Common Peroneal/Fibular nerve not functioning properly =

loss of movement or sensation in the foot and leg

Why do we classify autonomic neurons as either preganglionic neurons or postganglionic neurons?

because the ANS uses a two neuron system instead of a single neuron system as the SNS does. The preganglionic neuron travels from its origin in the brain or spinal cord to a ganglion (collection of cytons outside the CNS). The postganglionic neuron begins in and travels from the ganglion to the smooth muscle or gland being innervated.

Where are the ganglia in the sympathetic nervous system?

Just ventral and lateral to the **spinal cord**

Where are the ganglia in the parasympathetic nervous system?

within or close to the organ that postganglionic nerves innervate

Which neurons of the sympathetic nervous system would be termed “adrenergic neurons?”

 sympathetic neurons?

What neurotransmitter is released by adrenergic neurons?

norepinephrine

Give at least two examples of cholinergic neurons.

motor and parasympathetic neurons

What is the neurotransmitter released by cholinergic neurons?

ACh

Name two types of receptors that receive this neurotransmitter.

Nicotinic and muscarinic receptors  

What happens if you stimulate Beta 1 adrenergic receptors in the sinus (SA) node of the heart?

Increase in heart rate and contractility

What happens if you stimulate Beta 2 adrenergic receptors in the bronchi?

bronchodilation → increased airflow 

What happens if you stimulate Alpha 1 adrenergic receptors in blood vessels of the kidneys and stomach? 

Vasoconstriction 

What happens if you stimulate the Alpha 1 receptors in the sphincter muscles of the stomach and urinary bladder?

sphincter contraction

What happens in you stimulate Alpha 2 adrenergic receptors in blood vessels of exercising muscle?

vasodilation

Name some effector organs associated with the lesser splanchnic nerves (a pair of sympathetic nerves that arise from the thoracic sympathetic ganglia (T10-T11) and innervate several effector organs in the abdominal region.)

* Kidneys 


* Adrenal glands 
* Small intestine and colon 
* Ureter and bladder
* Male and female reproductive organs

Name some effector organs associated with the greater splanchnic nerves (a pair of sympathetic nerves that arise from the thoracic sympathetic ganglia (T5-T9) and innervate several effector organs in the abdominal region.)

* Stomach 


* Liver
* Gallbladder
* Pancreas
* Small intestine and colon  

Name some effector organs of the G.I. tract associated with the Vagus nerve (is a mixed nerve that supplies both parasympathetic and sympathetic innervation to several organs in the thorax and abdomen).

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* Esophagus 
* Stomach
* Small intestine and colon 
* Liver
* Pancreas

Where in the central nervous system do parasympathetic nerves originate?

The brainstem and the sacral spinal cord region (craniosacral)

Where in the CNS do sympathetic nerves originate?

thoracolumbar region of the spinal cord

I’m taking a Beta 1 receptor antagonist (blocker). What is this doing to my heart rate?  Is this doing anything to my airways?  Explain the physiology behind any changes seen as a result of taking this medication.

A Beta 1 blocker is going to decrease your heart rate and contractility. Beta 1 blockers reduce the heart rate by blocking the effects of norepinephrine and epinephrine on the beta 1 receptors in the heart, which slows down the electrical conduction system and decreases the number of times the heart beats per minute. Beta 1 blockers decrease the contractility of the heart muscle, which reduces the force of each heartbeat and the amount of blood pumped out of the heart with each beat. Typically there should be no significant effect to your airways, but some individuals may experience mild bronchoconstriction as a side effect of beta 1 receptor blockade due to an indirect effect on beta 2 receptors. These medications can be used to treat hypertension. 

When there is excessive tension in a muscle pulling on a tendon, damage to the muscle is prevented by the

golgi tendon reflex

The integration center for reflex arcs is always found within the…

CNS (spinal cord)