FORM & FUNCTION (NS Overview)

Question 1

Key functions of the NS:

Answer 1

-receives sensory info from the environment
>external: temperature, pressure, pain
>internal: osmotic pressure, BP
-process information
-generate motor response

Question 2

Key components of the NS:

Answer 2

-CNS: brain and spinal cord
-PNS: nerves and ganglia

Question 3

Brain:

Answer 3

-receives and processes sensory information
-initiates responses
-stores memories
-generates thoughts and emotions

Question 4

Spinal cord:

Answer 4

-conducts signals to and from the brain
-controls reflex activities

Question 5

Nerves:

Answer 5

-cranial, spinal, peripheral nerves conduct impulses to and from the CNS

Question 6

Ganglia:

Answer 6

-small groups of nerve cells outside the CNS
-sensory and autonomic

Question 7

Main functions of the NS (3 steps):

Answer 7

1. Sensory input (PNS)
2. Integration (CNS)
3. Motor output (PNS)

Question 8

Sensory input (PNS):

Answer 8

-collects data from internal and external environments via sensory receptors

Question 9

Integration (CNS):

Answer 9

-processes and interprets the sensory input and decides on the action to be taken

Question 10

Motor output (PNS):

Answer 10

-executes the action by activating muscles or glands

Question 11

NS coordinates with other systems:

Answer 11

-works with the endocrine system for physiological regulation
-interacts with the muscular system for movement control

Question 12

Neurons:

Answer 12

-functional unit of NS
-receives signals from the environment and within the body, integrates sensory info and generates output signals to an effector organ of the body to elicit an appropriate response
-info processing
-gives rise to nerves

Question 13

Neuroglia (>90% of the NS):

Answer 13

-most abundant cell types in the NS
-surround most of the neuronal cell bodies, processes of axons and dendrites
-provide structure and functional support for neurons

Question 14

Anatomy of a neuron:

Answer 14

-soma or perikaryon
-dendrites
-axon hillock
-axon
-terminal arborization and boutons

Question 15

Soma or perikaryon:

Answer 15

-cell body
-large spherical euchromatic nucleus and prominent nucleolus
-highly developed rER into aggregates of parallel cisternae and numerous polyribosomes
-golgi
-mitochondria found throughout
-neurofilaments are abundant (intermediate filaments)
-occasionally contain lipofusion

Question 16

Dendrites:

Answer 16

-elongated process that receive stimuli
-usually short and branched
-covered with many synapses
-cytoplasmic composition similar to cell body, but no golgi
-dendritic spines

Question 17

Dendritic spines:

Answer 17

-where synapses impinge on

Question 18

Axon:

Answer 18

-elongated processes that specialize in propagating nerve impulses (action potential)
-most neurons only have one
-axon hillock
-axolemma
-axoplasm

Question 19

Axon hillock:

Answer 19

-specialized in initiating nerve impulses (action potential)

Question 20

Axolemma:

Answer 20

-plasma membrane of the axon

Question 21

Axoplasm:

Answer 21

-cytoplasm of the axon
-contains mitochondria, cytoskeleton, cisternae of sER
-NO rER or polyribosomes

Question 22

Terminal arborization and boutons:

Answer 22

-where NT are released into synapse

Question 23

Different morphology of neurons:

Answer 23

-multipolar
-bipolar
-unipolar

Question 24

Grey matter:

Answer 24

-groups of neuronal cell bodies

Question 25

White matter:

Answer 25

-groups of axons

Question 26

Ganglion:

Answer 26

-groups of neuronal cell bodies in the PNS

Question 27

Nucleus:

Answer 27

-groups of neuronal cell bodies in the CNS

Question 28

Classification of neurons by function (3):

Answer 28

-motor (efferent) neurons -sensory (afferent) neurons -interneurons

Question 29

Motor (efferent) neurons:

Answer 29

-control effector organs such as muscle fibers and exocrine and endocrine glands -neuronal cell body located in CNS -signal direction: CNS to PNS

Question 30

Sensory (afferent) neurons:

Answer 30

-reception of sensory stimuli from the environment and from within the body -neuronal cell body is located within ganglion in the PNS -signal direction: PNS to CNS

Question 31

Interneurons:

Answer 31

-information processing

Question 32

Components of the PNS:

Answer 32

1. Sensory NS 2. Motor NS

Question 33

2 pathways in the PNS:

Answer 33

1. Somatic (voluntary) 2. Visceral (autonomic/involuntary)

Question 34

Somatic (voluntary) pathway:

Answer 34

-sensation: conscious -target: skeletal muscle

Question 35

Visceral (autonomic/involuntary) pathway:

Answer 35

-sensation: unconscious -targets: glandular cells, smooth and cardiac muscle -subdivision: sympathetic and parasympathetic

Question 36

PNS sensory pathways:

Answer 36

-similar both somatic and visceral -receive afferent impulses that go to the CNS -in both cranial and dorsal root of spinal nerves -neurons relay information from the ganglions nerve endings to the gray matter of the spinal cord via synapses with local neurons

Question 37

PNS motor pathways:

Answer 37

-differ between somatic and visceral

Question 38

Somatic motor pathway:

Answer 38

-one-neuron system (“on-off control”) -single motor neuron extends from CNS directly to the skeletal muscle fiber *voluntary

Question 39

Visceral motor (autonomic) motor pathway:

Answer 39

-two-neuron chain (“push-pull control”) -a preganglionic neuron from the CNS synapses onto a postganglionic neuron in an autonomic ganglion >postganglionic neuron innervates the target tissue (glandular cells, cardiac and smooth muscle) *involuntary