Peripheral Nervous System
Presentation
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Science
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9th - 12th Grade
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Hard
Barbara White
FREE Resource
27 Slides • 12 Questions
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Peripheral Nervous System
High School
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Learning Objectives
Define the Peripheral Nervous System (PNS) and its role in the body.
Identify the main components of the PNS, including cranial and spinal nerves.
Differentiate between the somatic and autonomic nervous systems.
Compare and contrast the functions of the sympathetic and parasympathetic divisions.
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Key Vocabulary
Neuron
The basic functional unit of the nervous system that transmits electrical and chemical nerve signals.
Synapse
The junction between two neurons where signals are chemically passed from one neuron to another.
Somatic Nervous System
The part of the peripheral nervous system that controls all your voluntary muscle movements.
Autonomic Nervous System
The part of the peripheral nervous system regulating involuntary functions like heartbeat and digestion.
Cranial Nerves
Twelve pairs of nerves that emerge directly from the brain to serve the head.
Spinal Nerves
Thirty-one pairs of nerves that emerge from the spinal cord to serve the body.
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What is the Peripheral Nervous System (PNS)?
The PNS is a network of nerves outside the Central Nervous System (CNS).
It acts as a communication link between the CNS and the entire body.
Sensory nerves send info to the CNS; motor nerves transmit instructions from it.
It includes the Somatic (voluntary) and Autonomic (involuntary) nervous systems.
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Solved Example 1
A patient's spinal nerves are counted. How many pairs of thoracic and lumbar nerves are there in total?
Step 1: Analyze and Sketch the Problem
Goal: Find the total number of thoracic and lumbar spinal nerve pairs.
Knowns: Thoracic nerves = 12 pairs; Lumbar nerves = 5 pairs.
Unknown: Total number of pairs.
Formula: Total = Thoracic pairs + Lumbar pairs
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Solved Example 1
A patient's spinal nerves are counted. How many pairs of thoracic and lumbar nerves are there in total?
Step 2: Solve for the Unknown
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Solved Example 1
A patient's spinal nerves are counted. How many pairs of thoracic and lumbar nerves are there in total?
Step 3: Evaluate the Answer
The calculation is a simple addition: 12 thoracic pairs plus 5 lumbar pairs equals 17 pairs.
The answer is correct and logically derived from the given data.
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Multiple Choice
What are the two main functional divisions of the Peripheral Nervous System?
Sensory and Motor Systems
Cranial and Spinal Systems
Central and Peripheral Systems
Somatic and Autonomic Systems
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Components: Cranial & Spinal Nerves
Cranial Nerves
There are 12 pairs of cranial nerves that exit from the skull to primarily serve the head and neck.
These nerves can be sensory for senses like vision, motor for muscle movement, or mixed with both functions.
They are responsible for transmitting signals between the different receptor organs and the brain.
Spinal Nerves
There are 31 pairs of spinal nerves that emerge from the vertebral column to serve the limbs and torso.
All spinal nerves are mixed nerves, meaning they have both sensory and motor functions for the body.
These are grouped by region: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.
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Solved Example 2
A patient has 8 pairs of cervical nerves, 12 pairs of thoracic nerves, and 5 pairs of lumbar nerves. How many total pairs of these specific spinal nerves does the patient have?
Step 1: Analyze and Sketch the Problem
Goal: Find the total number of specific spinal nerve pairs.
Knowns: 8 cervical pairs, 12 thoracic pairs, 5 lumbar pairs.
Unknown: Total number of these nerve pairs.
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Solved Example 2
A patient has 8 pairs of cervical nerves, 12 pairs of thoracic nerves, and 5 pairs of lumbar nerves. How many total pairs of these specific spinal nerves does the patient have?
Step 2: Solve for the Unknown
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Solved Example 2
A patient has 8 pairs of cervical nerves, 12 pairs of thoracic nerves, and 5 pairs of lumbar nerves. How many total pairs of these specific spinal nerves does the patient have?
Step 3: Evaluate the Answer
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Multiple Choice
What is a key difference between cranial nerves and spinal nerves?
Spinal nerves serve the head and neck, while cranial nerves serve the limbs.
Cranial nerves are all mixed, while spinal nerves can be purely sensory.
There are 31 pairs of cranial nerves and 12 pairs of spinal nerves.
Spinal nerves are all mixed (sensory and motor), while cranial nerves can be sensory, motor, or mixed.
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Nerve Structure
Connective Tissue Layers
The epineurium is the outermost layer of connective tissue that surrounds the entire nerve.
Bundles of neurons called fascicles are organized and wrapped by the perineurium.
The endoneurium is the innermost layer that encloses each individual nerve fiber.
Spinal Nerve Roots
The dorsal root has sensory nerve fibers that send signals to the spinal cord.
The ventral root contains motor nerve fibers that carry commands from the central nervous system.
These motor commands travel to the body's various muscles and glands to produce actions.
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Solved Example 3
A spinal nerve has 8 cervical pairs, 12 thoracic pairs, 5 lumbar pairs, 5 sacral pairs, and 1 coccygeal pair. Calculate the total number of spinal nerve pairs.
Step 1: Analyze and Sketch the Problem
Goal: Find the total number of spinal nerve pairs.
Knowns: Cervical = 8 pairs, Thoracic = 12 pairs, Lumbar = 5 pairs, Sacral = 5 pairs, Coccygeal = 1 pair.
Unknown: Total number of pairs.
Formula: Total pairs = sum of all nerve pairs
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Solved Example 3
A spinal nerve has 8 cervical pairs, 12 thoracic pairs, 5 lumbar pairs, 5 sacral pairs, and 1 coccygeal pair. Calculate the total number of spinal nerve pairs.
Step 2: Solve for the Unknown
Add the number of pairs from each spinal region.
Total = 8 + 12 + 5 + 5 + 1
Total = 31 pairs
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Solved Example 3
A spinal nerve has 8 cervical pairs, 12 thoracic pairs, 5 lumbar pairs, 5 sacral pairs, and 1 coccygeal pair. Calculate the total number of spinal nerve pairs.
Step 3: Evaluate the Answer
The calculation is a simple addition of the given values.
The sum correctly adds all the individual pairs to find the total.
The answer of 31 pairs is consistent with the information provided in biology resources.
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Multiple Choice
If a signal is being sent from the spinal cord to a muscle to cause contraction, which root would it travel through?
The epineurium
The dorsal root
The perineurium
The ventral root
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The Neuron: A Nerve Cell
A neuron is a nerve cell with a cell body, dendrites, and an axon.
Dendrites receive signals and carry them toward the cell body; axons send them away.
Axons can be myelinated for fast signals or unmyelinated for slower signals.
Neurons connect at a synapse, using chemical messengers called neurotransmitters to communicate.
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Multiple Choice
What is the correct pathway for a nerve signal through a single neuron?
Axon -> Cell Body -> Dendrite
Dendrite -> Axon -> Cell Body
Cell Body -> Axon -> Dendrite
Dendrite -> Cell Body -> Axon
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Functional Neuron Types & The Reflex Arc
Sensory neurons carry signals from sense organs to the central nervous system (CNS).
Motor neurons carry signals from the CNS to effector cells like your muscles.
Interneurons are connectors, relaying signals between sensory and motor neurons in the CNS.
A reflex arc is the neural pathway controlling a reflex, like pulling away from heat.
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Multiple Choice
In a reflex arc, which neuron type is responsible for carrying the signal from the spinal cord to a muscle?
Receptor neuron
Interneuron
Motor (efferent) neuron
Sensory (afferent) neuron
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Somatic vs. Autonomic Systems
Somatic System
Controls voluntary actions that you can consciously decide to perform.
It is responsible for the movement of your skeletal muscles.
Examples include walking, waving your hand, or picking up a book.
Autonomic System
Manages involuntary processes that happen without your conscious thought.
Controls internal organs and glands to maintain the body's internal balance.
Examples include your heartbeat, digestion of food, and your breathing rate.
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Solved Example 4
A car travels 434 km in 4.5 hours. What is its average speed?
Step 1: Analyze and Sketch the Problem
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Solved Example 4
A car travels 434 km in 4.5 hours. What is its average speed?
Step 2: Solve for the Unknown
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Solved Example 4
A car travels 434 km in 4.5 hours. What is its average speed?
Step 3: Evaluate the Answer
Check: 96.4 km/h * 4.5 h = 434 km.
The answer is correct.
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Multiple Choice
Which of the following actions is controlled by the Somatic Nervous System?
The digestion of food after a meal
Typing on a keyboard
The increase in your heart rate when you're scared
The constriction of your pupils in bright light
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Divisions of the Autonomic Nervous System
Sympathetic Division
Prepares the body for action and stress, also known as the 'fight or flight' response.
This division uses the neurotransmitter norepinephrine to stimulate the body and its responses.
Key effects include increasing heart rate, dilating pupils, and relaxing the body's airways.
Parasympathetic Division
This division is active during calm periods, and is known as the 'rest and digest' system.
It uses the neurotransmitter acetylcholine to help conserve and restore the body's energy.
This results in slowing the heartbeat, constricting pupils, and stimulating digestive activity.
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Solved Example 5
A patient's heart rate is 70 beats per minute (BPM) at rest. During a 'fight or flight' response, their heart rate increases by 60%. What is the patient's new heart rate?
Step 1: Analyze and Sketch the Problem
Goal: Find the new heart rate after a 60% increase.
Knowns: Resting heart rate = 70 BPM; Percentage increase = 60%.
Unknown: New heart rate.
Formula: New Rate = Resting Rate + (Resting Rate × Percentage Increase)
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Solved Example 5
A patient's heart rate is 70 beats per minute (BPM) at rest. During a 'fight or flight' response, their heart rate increases by 60%. What is the patient's new heart rate?
Step 2: Solve for the Unknown
Calculate the increase in heart rate: 70 BPM * (60 / 100) = 42 BPM.
Add the increase to the resting heart rate: 70 BPM + 42 BPM = 112 BPM.
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Solved Example 5
A patient's heart rate is 70 beats per minute (BPM) at rest. During a 'fight or flight' response, their heart rate increases by 60%. What is the patient's new heart rate?
Step 3: Evaluate the Answer
The new heart rate is 112 BPM, which is a significant increase and is consistent with a 'fight or flight' response.
The calculation is arithmetically correct.
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Multiple Choice
If you are in a stressful situation and your heart starts racing, which division of the ANS and which neurotransmitter are primarily responsible?
Parasympathetic division and norepinephrine
Sympathetic division and norepinephrine
Sympathetic division and acetylcholine
Parasympathetic division and acetylcholine
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Common Misconceptions About the PNS
Misconception | Correction |
|---|---|
The PNS is only a passive wiring system. | The PNS actively processes information, like in reflex arcs. |
34 Multiple Choice How do the roles of the dorsal and ventral roots of a spinal nerve differ in transmitting information? The dorsal root sends sensory information to the spine, while the ventral root sends motor commands from the spine. Both roots send motor commands, but to different muscles. The dorsal root sends motor commands from the spine, while the ventral root sends sensory information to the spine. Both roots send sensory information, but to different parts of the brain. 35 Multiple Choice Why are myelinated axons able to conduct nerve impulses faster than unmyelinated axons? Because they are wider in diameter. Because they are shorter in length. Because they use different neurotransmitters. Because the myelin sheath allows the signal to jump between gaps, speeding up transmission. 36 Multiple Choice A person eats a large meal and then relaxes in a chair. Analyze which division of the Autonomic Nervous System would be dominant and predict two specific effects it would have on their body. Parasympathetic division; dilated bronchioles and inhibited saliva production. Sympathetic division; increased heart rate and inhibited digestion. Parasympathetic division; increased saliva production and increased digestive activity. Sympathetic division; constricted pupils and decreased heart rate. 37 Multiple Choice Imagine a doctor tests a patient's reflex by tapping their knee. What evidence would suggest a problem with the interneurons in the patient's reflex arc? The patient's leg kicks with an exaggerated motion. The patient feels the tap but the leg does not kick. The patient neither feels the tap nor does the leg kick. The patient's leg kicks, but they do not feel the tap. 38 The PNS connects the CNS to the body and has Somatic (voluntary) and Autonomic (involuntary) systems. It contains 12 cranial nerve pairs and 31 spinal nerve pairs. The Autonomic system has Sympathetic ('fight or flight') and Parasympathetic ('rest and digest') divisions. These divisions work in opposition to maintain the body's internal balance, or homeostasis. 39 Poll On a scale of 1-4, how confident are you about the concepts covered in today's review? 1 2 3 4 Show answer Auto Play Slide 1 / 39 SLIDE 38 questions Chemical Reactions - Types of Reactions Presentation • 9th - 12th Grade 34 questions Unit 2- Rocks and Minerals Presentation • 9th - 12th Grade 30 questions Unit 2.6: Fossil Fuels Presentation • 9th - 12th Grade 35 questions Regulating the Cell Cycle + Cancer (part 3) Presentation • 9th - 12th Grade 35 questions Nuclear fission vs fusion Presentation • 9th - 12th Grade 10 questions GPA Lesson Presentation • 9th - 12th Grade 7 questions Albert Einstein Quiz • 3rd Grade 31 questions Bridge A Review Quiz • 3rd Grade 6 questions Blue Sue and Red Ruth Quiz • 3rd Grade 8 questions (Day12 HW) Inverse Trig Ratios Quiz • 9th Grade 20 questions Summer Geometry QUIZ (Week3) Quiz • 9th Grade 16 questions Theme Practice Quiz • 7th Grade 20 questions Taxes Quiz • 9th - 12th Grade |
