RAP 7 CH 13 - This is the study guide for an in class quiz PDF

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This is the study guide for an in class quiz...

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Study Guide for BMSP 2135 – Readiness Assurance Test 7 – Part 2 of 3 Chapter 13 – The Peripheral Nervous System Module 13.1 Overview of the Central Nervous System Divisions of the PNS What are the two functional divisions of the PNS? What are the two subdivisions of the sensory division? What type of information is carried by each division? What are the two subdivisions of the motor division? What type of information is carried by each division? 

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PNS Sensory/Afferent Division o Somatic sensory carries signals from muscles, bones, and joints, and the skin, as well as special sensory signals; detects general senses o Visceral sensory carry signals from organs PNS motor/Efferent Division o Somatic motor division carries signals to skeletal muscles; voluntary o Visceral motor division = Autonomic nervous system, sympathetic and parasympathetic neurons carry signals to organs; detects internal stimuli (blood pressure, etc.); involuntary

What is another name for the visceral motor division? Autonomic nervous system What are the two divisions of the autonomic nervous system? Sympathetic nervous system: “fight or flight” division of the ANS that prepares the body for exercise, emergency, and emotion Parasympathetic nervous system: “rest and digest” division of the ANS that promotes maintenance functions such as defecation, diuresis, and digestion Overview of Peripheral Nerves and Associated Ganglia What are the main organs of the PNS? Peripheral nerves What does a nerve consist of? Axons of many neurons bound together by common connective tissue sheath What is a mixed nerve? A motor nerve? A sensory nerve? Mixed nerve: they contain both sensory and motor neurons Motor neve: contain mostly motor neurons Sensory nerve: contain only sensory neurons

What two structures connect spinal nerves to the spinal cord? Anterior root and posterior root What does the anterior root consist of? Contains motor neurons from the anterior horn What does the posterior root consist of? Sensory neurons that enter the posterior horn Review! Most sensory neurons are what type of neuron? (see the table on page 387)

For the

, where are the somas located? Posterior root ganglion What is the term for a collection of somas in the PNS? ganglia Classify each of the following as sensory, motor, or mixed: Anterior root – motor Posterior root- sensory Spinal nerve – mixed How many spinal nerves are there? 31 pairs What are cranial nerves? Do cranial nerves have roots? They attach to the brain and mainly innervate structures of the head and neck No roots What are the connective tissue sheaths in a nerve? What does each surround? 1. Epineurium, surrounds a peripheral nerve

2. Perineurium, surrounds a fascicle of a peripheral nerve

3. Endoneurium, connective tissue that surrounds an axon within a peripheral nerve (Does this terminology seem familiar? It is similar to muscles)

Label Figure 13.2 on page 480.

Functional Overview of the PNS What structures detect sensory stimuli? Sensory receptors What structures deliver that information to their destination? Spinal or cranial nerves What is the destination for that information? Cerebral cortex If there is a motor response, what sends out the signal? Motor areas of the brain What is the name for neurons that carry signals from the spinal cord to the effector? Lower motor neurons Review: If the signal is sent along a spinal nerve, where are the somas located?

In which root of the spinal nerve will the axons travel?

Module 13.2 The Cranial Nerves The cranial nerves are numbered using Roman Numerals (don’t ask me why). If you need to brush up on your Roman Numerals, check out this video. The good news is that you only have to go up to 12. How many pairs of cranial nerves does a person have? 12 How many total? 24

Label the cranial nerves. You will need to learn their names, Roman numerals, function and functional classification (motor, sensory, or mixed). See the mnemonic devices on page 481. There are more on the internet (and some that I can’t print in this review sheet).

The Sensory Cranial Nerves What are the three sensory cranial nerves? Olfactory (I), Optic (II), and vestibulocochlear (VIII) These cranial nerves should be a review, since we already covered the special senses chapter. CN I – Olfactory What structures in what bone does this nerve pass through? Ethmoid bone (cribriform plate) Where do the axons end? What is found in this structure? Medial temporal lobe; has chemoreceptors What structure carries the olfactory signals to the cerebrum? Olfactory tract What cerebral lobe initially processes sound? temporal Review – The signal is also sent to the limbic system. In one word, how could you summarize the function of the limbic system?

CN II – Optic Read the entry in table 13.1 and fill in the image below. Also label optic radiations. You only need to know thalamus (not lateral geniculate nucleus).

CN VIII – Vestibulocochlear nerve

Label the image below. You do not need to know the

Review: In which cerebral lobe is the primary auditory cortex located?

The Motor Cranial Nerves Label the three cranial nerves in the image below. Note the structure that each innervates. The superior oblique travels through the trochlea and is innervated by the trochlear nerve. The abducens nerve innervates the medial rectus muscle, which abducts the eyes. The oculomotor nerve innervates the other muscles of the eye (occulo – eye, motor – muscle)

The accessory nerve is the only cranial nerve that has a component from the spinal cord. What does it innervate? Certain muscles of speech, and the spinal component innervates the head and shoulder What is the name for CN XII? Hypoglossal What is the meaning of this name? Below the tongue What is its function? Innervates the muscles of the tongue (no role in taste)

The Mixed Cranial Nerves CN V – Trigeminal nerve. The trigeminal nerve has three branches (tri – three). It is the primary sensory nerve for the face. What it its motor function? Mandibular nerve; its motor axons supply the masseter and temporalis muscles CN VII – Facial nerve. What is the primary sensation detected by the facial nerve? Taste sensation from chemoreceptors and somatic sensation from external ear, palate, and nasal cavity Review – Remember the Muscle list for the exam? Which of those muscles were innervated by the facial nerve?

CN IX – What is the name for CN IX? What does its name mean? Glossopharyngeal; glosso = tongue, pharynx = throat It senses taste (from the back third of the tongue). It also innervates muscles of the pharynx CN X – What is the name for CN X? Vagus This cranial nerve is unique because it innervates many visceral organs including those in the thoracic and abdominal cavity. It is important in the parasympathetic NS and we will review it more in the ANS chapter.

Module 13.3 The Spinal Nerves Review – What two roots attach a spinal nerve to the spinal cord? What type of fibers are contained in each? Anterior ( motor) and Posterior (sensory) How long is a spinal nerve? 1-2 cm What are the names of the two large branches of the spinal nerve? Posterior Ramus and Anterior Ramus Is the posterior ramus sensory, motor, or mixed? Where does it travel? Is the anterior ramus sensory, motor, or mixed? Where does the anterior ramus travel? Both mixed (sensory and motor); travel is based on name What is the name of the small branch of the spinal nerve? This branch contains autonomic fibers and will be covered in the ANS chapter. Rami communicanes What is a nerve plexus? Nerve networks Which branches form a plexus? Cervical, Brachial, Lumbar, and Sacral

Cervical Plexuses Where is the cervical plexus located? Deep in the neck, lateral to the first and fourth cervical vertebrae What major nerve arises from the cervical plexus? What does it innervates? Phrenic nerve, supplies the diaphragm Brachial Plexuses Where is the brachial plexus located? Anterior rami from C5-T1; 5 major nerves are: axillary, radial, musculo-cutaneous, median, and ulnar What are the five major nerves that arise from the brachial plexus? Label those five nerves in the diagram. You do not need to label the other items or fill in the table.

Thoracic Spinal Nerves Do the anterior rami of thoracic nerves form a plexus? No What is the name for the nerves that form from anterior rami? Intercostal nerves Lumbar Plexuses Where is the lumbar plexus located? Lie anterior to the vertebrae, serve pelvis and lower extremity What is the name of the largest nerve that arises from the lumbar plexus? Femoral nerve Sacral Plexuses Where is the sacral plexus located? Form from the anterior rami of L4-S4; innervates structures of pelvis and gluteal region to serve lower extremity What is the name of the largest nerve that arises from the sacral plexus? What is the largest and longest nerve in the body? Sciatic nerve

Module 13.4 Sensation Part II: Role of the PNS in Sensation

From PNS to CNS: Sensory Reception Describe the basic pathway for sensory information 1. Stimulus is detected by sensory receptors of the PNS 2. Transmitted by PNS sensory neurons to the CNS 3. Integrated and interpreted by the CNS neurons Sensory Receptors What is sensory transduction? Conversion of a sensory stimulus to an electrical signal Where does sensory transduction take place? Sensory receptors Name two types of sensory receptors. Encapsulated nerve ending (have supporting cells) and free nerve endings

Sensory Transduction How does pressure lead to an action potential in a somatic sensory neuron? Opens gated sodium ion channels What is adaptation? When some receptors respond rapidly and with high intensity but stop sending stimuli after a certain period of time Which type of receptors will stop sending a signal even though the stimulus is still present? Rapidly adapting receptors Which type of receptors continue to send a signal? Slowly adapting receptors Classification of Sensory Receptors What is the name for receptors that detect stimuli originating outside the body? Give an example of this type of receptor. Exteroceptors What is the name for receptors that detect stimuli originating inside the body? Give an example of this type of receptor. Interoceptors

Based on the type of the stimuli detected, name five categories of receptors. Mechanoreceptor: both Thermoreceptor: exteroceptors Chemoreceptor: both Photoreceptor: exteroceptors Nocicecptor: exteroceptors Types of Mechanoreceptors What are proprioceptors? Located in the musculoskeletal system, where they detect movement and position of joint or body part Sensory Neurons Most sensory neurons are what type of neuron? Pseudounopilar (cell body with two axons) Where are the cell bodies of sensory neurons located? Posterior root ganglion

What is the peripheral process of a sensory neuron? Long axon What is the central process of a sensory neuron? Exits cell body and travels through the posterior root of the spinal cord to enter the posterior horn Transmits an AP from the peripheral process to the posterior horn Note that an AP which begins at the sensory receptors located on nerve endings will be propagated to the end of the central process.

Classification of Sensory Neurons What two factors determine the speed of transmission of axons? Diameter and thickness of myelin sheath Is proprioceptive information transmitted quickly or slowly? Based on this, what type of axons would you expect to find on proprioceptors?

Quickly with thick myelin sheath and large diameter Is temperature information transmitted quickly or slowly? Based on this, what type of axons would you expect to find on thermoreceptors? Slowly; small diameter with little myelin sheath Is pain information transmitted quickly or slowly? Based on this, what type of axons would you expect to find on nociceptors? Slowly; small diameter with little myelin sheath Which area contains more sensory neurons, the fingertips or the forearm? Fingertips Which has a larger sensory field, sensory neurons on the fingertip or on the forearm? Forearm Describe how you would measure the two-point discrimination threshold. Two stimuli are placed together on the skin; and then they are moved a part so that they are detected separately

Dermatomes and Referred Pain A dermatome is a segment of ____skin________. Each dermatome is determined by the _____spinal nerve____ that serves it. What is referred pain? Why does it occur? Painful stimuli that are perceived as cutaneous pain along a specific dermatome This is because the nerves that carry the pain signals from a certain area serve particular dematomes

Putting It All Together: The Big Picture of the Detection and Perception of Somatic Sensation by the Nervous System Teach someone about how we are able to perceive touch. Narrate the image below!

Module 13.5 Movement Part II: Role of the PNS in Movement From CNS to PNS: Motor Output Describe the motor pathway that leads to a voluntary muscle contraction. 1. Upper motor neurons in the primary motor cortex of the cerebrum “decide” to move 2. They send messages to the lower motor neurons, which release AcH onto the muscle fiber The Role of Lower Motor Neurons Where is the cell body of a lower motor neuron located? Within the CNS ( in either the anterior horn of the spinal cord or brainstem) Review – if the lower motor neuron is located in the spinal cord, its axons would be located in which root of the spinal nerve? anterior

Where does the axon end? In the PNS Putting It All Together: The Big Picture of Control of Movement by the Nervous Sytsem Use the image below to narrate the story of how we voluntarily move muscles.

Module 13.6 Reflex Arcs: Integration of Sensory and Motor Function Read the first paragraph here. It is a great into to reflexes. Reflex Arcs What is a reflex? Programmed, automatic responses Describe a reflex arc. 1. PNS detects and delivers stimulus to CNS 2. CNS integrates with the PNS 3. PNS delivers motor response from CNS to effectors The Role of Stretch Receptors in Skeletal Muscles Name two structures that detect stretch. Where is each located?

2 types of muscle spindles: extrafusal muscle fibers and infrafusal muscle fibers Types of Reflexes How many neurons are involved in a monosynaptic reflex? Single synapse between a sensory and motor neuron What is the term for a reflex that involves more than one synapse? Polysynaptic reflex What are somatic reflexes? Involve with cranial or spinal nerves; somatic sensory or motor neurons Simple Stretch Reflexes What structure detects when a muscle is stretched? Muscle spindals Where is the signal sent? Spinal cord Where does it synapse with a motor neuron? Spinal cord Review: through which root does the motor neuron travel? Anterior

What is the best-known example of a stretch reflex? Have you ever tried not to move your muscle in the doctor’s office? Were you successful? How can you explain this based on the anatomy of the reflex arc? Patellar/knee-jerk reflex Flexion (Withdrawal) and Crossed Extension Spinal Reflexes Refer to figure 13.20 on page 511. What is detecting the stimulus? Nociceptive afferents Review: What type of receptor detects pain? nocioceptors Review: Where is the soma of this neuron located? Notice that this neuron is synapsing with two neurons. Is that typical?

One motor neuron causes the hip ___extensors___ of the _____(left/right) _____ leg to contract. The other motor neuron causes the hip _extensors_____ of the __ (left/right) ____ leg to contract. Which of the above occurs first? Or do they occur simultaneously? Simultaneous Review: Which neuron decussates? Which neurons are interneurons? Which neurons are part of the PNS? The CNS?

Cranial Nerve Reflexes The gag reflex and the corneal blink reflex are two examples of what type of reflex? Cranial nerve relfexes...