CVA Nervous

Central Nervous Sys

brain + spinal cord

Peripheral Nervous Sys

all other nervous tissue that aren’t the brain or spinal cord

Receptors

cells/ tissues that receive stimuli

Effectors

cells/ tissues that respond to nervous signals

Neurons

nervous cells that transmit information

Neuroglia

support, nourish, protect neurons and bind nervous tissue together

Basic structural and functional unit of the nervous sys

Neuron

How do neurons transmit info?

As nervous impulses/ “action potentials”

Axon

long tail of the neuron that sends signals

Dendrites

part of neuron which branching processes and receive signals

Myelin

Protein covering some axons to speed up transmission

Synapse

Gap @ junction b/w neurons

Neurotransmitter(s)

chemical signals sent from one neuron to another

Peripheral nerves classified by

Innervation

Somatic nerve

serve skeletal muscles, skin, etc.

Visceral nerve

serve int. organs

Afferent (=sensory)

Send signals TOWARD CNS

Efferent (=motor)

Sends signals FROM CNS

Dorsal spinal nerves carry

afferent fibers

Ventral spinal nerve carry

Efferent fibers

Dorsal root ganglia contain

bodies of afferent neurons

Autonomic ganglia contain

bodies of autonomic effector nerves

CN 0 is also known as

terminal nerve

CN I is also known as

Olfactory

CN II is also known as the

Optic

CN III is also known as

Oculomotor

CN IV is also known as

Trochlear

CN O function:

recently discovered but NOT present in birds;

known functions unclear

CN I function:

SENSORY nerve for smell

CN II function:

Not really a nerve, rather an extension of brain;

SENSORY nerve for vision

CN III function:

MOTOR nerve for eye mvmt

CN IV function:

MOTOR nerve for eye mvmt

CN V is also known as

Trigeminal

CN VI is also known as

Abducens

CN VII is also known as

Facial

CN VIII is also known as

Vestibulocochlear

CN V function:

SENSORY + MOTOR nerve to the face;

3 branches: ophthalmic, maxillary, and mandibular

CN VI function:

MOTOR nerve for eye mvmt

CN VII function:

SENSORY nerve for taste and skin + MOTOR (2nd arch);

5 branches to face

CN VIII function

SENSORY nerve for balance (vestibulo—) + hearing (—cochlear)

CN IX is also known as

Glossopharyngeal

CN X is also known as

Vagus

CN XI is also known as

(Spinal) Accessory

CN XII is also known as

Hypoglossal

CN IX function:

SENSORY nerve for taste + MOTOR never (3rd arch)

CN X function:

SENSORY + MOTOR nerve for all over the body

CN XI function:

MOTOR nerve to neck, pectoral girdle, & (maybe) heart

CN XII function:

MOTOR nerve to neck

Cranial nerve evo hypothesis

Each head segment was originally innervated by separate dorsal and ventral roots, similar to modern dorsal and ventral spinal roots

The association b/w CN and branchial arches are

highly conserved across vertebrates

In mammals, the left recurrent laryngeal nerve (RLN) is trapped by

left aortic arch during development

Autonomic nervous sys controls

involuntary, internal processes to maintain homeostasis

Sympathetic nervous sys

“fight or flight”, prepares for activity, slows digestion

Parasympathetic nervous sys

“rest and digest”, lowers activity level, promotes digestion

The Hindbrain consist of

Medulla oblongata + Pons + Cerebellum

The Midbrain consist of

Tectum (SEONSORY) +Tegmentum (MOTOR)

The Forebrain consist of

Cerebrum + Diencephalon

The “brain stem” incl hindbrain + midbrain EXCEPT

Cerebellum + Colliculi

Forebrain enlargement ass. w/

Increased reliance on olfaction (smell);

Complex behaviors and motor control;

Terrestrial posture and locomotion in amniotes

Forebrain enlarges in EVERY vert. group; related to—

which function are needed for lifestyle

Medulla oblongata function:

manages many autonomic processes

Pons: built + function

enlargement of hindbrain floor in mammals; manages comm. b/w cerebellum and cerebrum

Cerebellum function

manages but does not initiate motor signals

The cerebellum is ABSENT in

agnathans

The cerebellum, is PRESENT in

gnathostomes

Tectum: location and function

dorsal part, processes SENSORY input

Superior and inferior colliculi are

parts of tectum in mammals

Optic tectum is

visual part of tectum in most vertebrates

Torus semicularis

Lateral line part of tectum in fish

Tegmentum function + location

ventral part, sends MOTOR signals via CN III + IV

Midbrain phylogeny in Fishes & Amphibians

Midbrain usually most prominent part of brain;

Tectum receives direct input from eyes (CN I), skin, and ears/semicircular canals (CN VIII);

Tegmentum also quite large

Midbrain phylogeny in Amniotes

Tectum relays visual and auditory input to cerebrum via thalamus (as in all vertebrates);

Amniotes (esp. mammals) can also get visual information directly from thalamus to cerebrum

Diencephalon

forebrain outside of cerebrum

Epithalamus

includes pineal gland that’s involved in circadian rhythms

Hypothalamus

manages aspects of homeostasis

Dorsal thalamus aka Thalamus

coordinates incoming sensory signals to other part of brain

Ventral thalamus

small region b/w midbrain and diencephalon

Cerebral hemispheres are connected via

corpus callosum

SENSORY input is processed in

specific areas of telencephalon