Exam 2 - Neurons, Sensory, & Reflexes

Question 1

Neurons

Answer 1

Basic unit of the nervous system

Question 2

Sensory-motor integration

Answer 2

Basic principle of nervous system

Question 3

Reflexes

Answer 3

The basic unit for sensory-motor integration

Sensory neuron connecting to motor neuron for response

Question 4

Dendrites

Answer 4

Branches

Major receptor of signals for neuron

Question 5

Cell body

Answer 5

Also: soma/perikaryon

Process and integrates signals

Emits outgoing signals from neuron

Question 6

Axon

Answer 6

Major transmitter of signals for neuron

Question 7

Cytoplasm

Answer 7

Consists of protein molecules in watery substance within membrane

Question 8

Nucleolus

Answer 8

Centerpiece within nucleus

“Heart within heart”

Question 9

Nucleus

Answer 9

Heart of neuron

Control center of neuron

Question 10

Mitochondria

Answer 10

Energy source for cell

Question 11

Axon hillock

Answer 11

No nissl bodies

Gateway to cell

Area where axon meets cell body

Question 12

Nissl bodies

Answer 12

Protein synthesis

Not in axon hillock

Question 13

Axon terminals

Answer 13

Root-like telodendra endings of axon

“Tree roots”

Question 14

Axon boutons

Answer 14

Also: buttons

Knob on end of axon terminals for presynaptic function

Question 15

Synaptic vesicles

Answer 15

Within axon boutons

Packets of neurotransmitter substances that release to other neurons or muscles

Question 16

Myelination

Answer 16

Allows for rapid transmission of neuronal impulses

Question 17

Schwann cells

Answer 17

Cells that form myelin around axons

Question 18

Nodes of ranvier

Answer 18

Space between two internodes (segments) of myelin

Question 19

Nervous system function

Answer 19

Sensory afferent (input) to motor efferent (output)

Sensory info from outside body travels into nervous system by sensory neurons and contacts central nervous system through dorsal horn (in spinal cord and brain stem)

Question 20

Sensory (afferent) receptors

Answer 20

Exterocepters

Propriocepters

Interocepters

Question 21

Exterocepters

Answer 21

Receive stimuli on surface of body

Includes: vision, sound, smell, and superficial skin (cutaneous) sensation

Question 22

Propriocepters

Answer 22

Receive stimuli from muscles, tendons, and joints

Includes inner ear

Not touch, but position in space

Question 23

Interocepters

Answer 23

Receive stimuli from internal surfaces and include sensations of pain, pressure, or distension (swelling) from smooth muscles, organs, and viscera

Question 24

Energy transformers

Answer 24

Receive and transform energy based on the type of signals they process

Mechanoreceptive

Chemoreceptive

Thermoreceptive

Nociceptive

Question 25

Mechanoreceptive

Answer 25

Touch, pressure, and position Stretch, vibration

Question 26

Chemoreceptive

Answer 26

Gustatory (taste) and olfaction (smell)

Question 27

Thermoceptive

Answer 27

Temperature

Question 28

Nociceptive

Answer 28

Pain receptors for noxious stimuli affecting cells and tissues

Question 29

Graded potential

Answer 29

Leads to action potential when strong enough Occurs in dendrites and soma when there is a change in voltage Spreads in all directions and dies out as it spreads

Question 30

Action potential

Answer 30

Axon hillock to axon to terminal buttons Sends impulses for long distances Excitatory or inhibitory All or nothing; keeps strength

Question 31

Generating action potential (1-3)

Answer 31

1. Cell membrane polarized @ -70mv; resting membrane potential 2. Cell body receiving excitatory and inhibitory signals from other neurons 3. Signals depolarize membrane

Question 32

Generating action potential (4 and 5)

Answer 32

4. Axon hillock stimulated; action when graded is strong | 5. Action travels down axon with same speed and strength to terminals

Question 33

Generating action potential (6-8)

Answer 33

6. Action continues from channels opening and closing to spread depolarization effect 7. When depolarization reaches telodendra, presynaptic cell releases neurochemicals 8. Presynaptic cell unresponsive for 0.8 ms

Question 34

Generating action potential (9 and 10)

Answer 34

9. Protein pumps activate and repolarize presynaptic cell | 10. Post synaptic cell receives neurotransmitter across synaptic cleft and responds

Question 35

Basic components of reflex pattern

Answer 35

Sensory receptor/afferent neuron Lower motor neuron (alpha motor neuron) and muscle fibers it activates

Question 36

Motor unit

Answer 36

Made up of lower motor neuron and muscle fibers

Question 37

Lower motor neuron

Answer 37

Also alpha motor neuron and final common pathway for response from nervous system In ventral horn of brain stem and spinal cord

Question 38

Motor/efferent information travel

Answer 38

Leaves nervous system by lower motor neuron located in ventral horn (in spinal cord and brain stem)

Question 39

Basic reflex patterns

Answer 39

Monosynaptic stretch reflex Polysynaptic reflex arc Gamma loop

Question 40

Monosynaptic stretch reflex

Answer 40

Most direct reflex response 1. Proprioceptive input (muscle spindle) to dorsal root ganglion into spinal/cranial dorsal horn 2. Afferent input directly to lower (alpha) motor neuron in spinal/cranial ventral horn 3. LMN sends efferent to muscle fibers 4. Muscle moves in quick, unsustained, and phasic pattern

Question 41

Polysynaptic reflex pattern

Answer 41

Second most direct reflex 1. Cutaneous input to dorsal root ganglion 2. Afferent connects with interneuron between spinal/cranial dorsal and ventral horns 3. Interneuron connects with LMN in spinal/cranial ventral horn 4. LMN efferent to muscle fibers 5. Muscle moves in quick, unsustained, and phasic pattern

Question 42

Gamma loop

Answer 42

Indirect reflex 1. Cutaneous input into dorsal root ganglion and into spinal/cranial dorsal horn 2. Afferent axon connects with gamma motor neuron in spinal/cranial ventral horn 3. GMN sends efferent to muscle spindle telling it to stretch 4. Muscle spindle stretches 5. Stretch causes spindle to send afferent to dorsal root ganglion and into spinal/cranial dorsal horn 6. Spindle afferent connects with LMN in spinal/cranial ventral horn 7. LMN sends efferent stimulation to muscle fibers 8. Muscle moves in relatively sustained pattern