Nervous Tissue

Front 1

Transmission of signal

Back 1

Neuron carries signal by depolarization of its plasma membrane. Signal is transmited to the next neuron or to another cell at a synapse via exocytosis of a neurotransmitter. This diffuses extracellularly, then binds to the next plasma membrane - paracine

Front 2

CNS

Back 2

brain and spinal cord; also cranial nerve II, neurons, and oligodendrocyte glial cells

Front 3

PNS

Back 3

Nerves, ganglia, motor and sensory nerve endings-neuron and Schwann/satellite glial cell bodies outside of the cranial cavity and spinal cord

Front 4

Norepinephrine

Back 4

Released by the sympathetic nervous system from post-ganglionic fibers

Front 5

Acetylcholine

Back 5

Released from pre-and post-ganglionic fibers of the parasympathetic nervous system

Front 6

Exteroreceptors

Back 6

afferent sensory receptors that respond to external stimuli

Front 7

Enteroreceptors

Back 7

afferent sensory receptors that respond to internal stimuli

Front 8

Proprioreceptors

Back 8

afferent sensory receptors that respond to mechanical stimuli

Front 9

Derivatives of neural tube

Back 9

CNS: neurons of brain, glialcells (astrocytes and oligodendrocytes), ependymal cells, epithelial cells

Front 10

Derivatives of neural crest

Back 10

PNS: Post-ganglionic neurons of ANS, Schwann cells and satellite cells of ganglia, sensory nerves, pia mater and arachnoid, chromaffin cells of adrenal medulla, melanocytes of epidermis

Front 11

Derivaties of placodes (from embryonic epithelia)

Back 11

lens vesicle and lens of eye, cochlea and vestibule of inner ear, olfactory epithelium of nasal cavity, and cranial nerve sensory ganglia

Front 12

Multipolar neuron

Back 12

Multiple dendrites and one axon - interneurons, motor neurons, autonomic PNS

Front 13

Bipolar neurons

Back 13

Single axon and a single dendrite at opposite poles of a cell body. Found only in sensory neurons

Front 14

Pseudounipolar neurons

Back 14

Single branching axon but no dendrites. Began as bipolar, but the two processes fused. Functionally bipolar. Found in peripheral sensory ganglia, such as the dorsal root ganglia

Front 15

Neuron structure

Back 15

Has fried egg nucleus with prominent nucleolus. Perikaryon contains usual organelles found in cells and polyribosomes and r ER are visible as Nissl substance bodies with cationic dyes.

Front 16

Dendrites

Back 16

Carry impulses to the soma. Contain Nissl bodies, mitochondria, neurofilaments, microtubules, but no Golgi.

Front 17

Axons

Back 17

Trasmits impulses from the perikaryon. Arises from axon hillock (has no Golgi or NIssl). Axoplasm has microtubules and neurofilaments, enzymes, mitochondra, and smooth ER, but no Nissl substance or Golgi

Front 18

Axolemma

Back 18

Axon plasma membrane,usually surrounded by glial cells as a myelinated sheathoran unmyelinated cellular layer

Front 19

Bouton terminaux

Back 19

Contact points of the synapse

Front 20

Synapse

Back 20

formed by thickened pre- and post-synaptic membranes with a cleft in between

Front 21

Cholinergic receptors

Back 21

bind acetylcholine

Front 22

Adrenergic receptors

Back 22

bind catecholamines like epinephrine, norepinephrine, and dopamine

Front 23

Structure of Astroctyes

Back 23

Macroglia of the CNS. Largest of the neuroglia with large, light oblong nuclei and long tentacle processes. Cytoplasm has glial fibrillary acidic protein

Front 24

Function of Astroctyes

Back 24

Provide physical, metabolic, and functional support of neurons. Processes form inter-endothelial tight junctions - the blood-brain barrier

Front 25

Glymphatic hypothesis

Back 25

Astroctytic end-feet may create an extravascular compartment around the capillaries containing CSF that control its flow through the parenchyma - like lymphatic drainage.

Front 26

Glia limitans

Back 26

isolates vascularized pia mater from underlying nervous tissue

Front 27

Oligodendroglia

Back 27

CNS cells that have small, round, dense nuclei that are smaller than astroctyes and myelinate neuronal axons in the CNS. One oligo can myelinate a single internodal segment of many different axons

Front 28

Ependymal cells

Back 28

line ventricles and central canal of the spinal cord. They are connected by tight junctions and desmosomes and contain microvilli that resorb CSF

Front 29

Choroid plexus

Back 29

structure in the ventricles of the brain where CSF is produced as an ultrafiltrate of plasma from underlying capillaries

Front 30

Microglia

Back 30

The CNS's version of macrophages. Enter CNS following injury to remove debris

Front 31

Schwann cells

Back 31

PNS equivalent of an oligo. Ensheaths small axons and myelinates one internodal segment of one axon. Surrounded by external lamina - mitotically capable if endoneurium is present, allowing axonal regeneration

Front 32

Satellite cells of PNS

Back 32

provide support for neuron cell bodies in PNS.

Front 33

Myelin

Back 33

a multilaminar, phospholipid-rich sheath

White by H&E, black by osmium.

Front 34

nodes of Ranvier

Back 34

Unmyelinated parts of myelinated axons. Covered by astrocytic end-feet in CNS and by external lamina of Schwann cells in PNS. Looks like two hot dog buns coming together

Front 35

Saltatory conduction

Back 35

Depolarization occurs at nodes, so the electrical current skips down the axon

Front 36

Nerve

Back 36

Nerve fiber axons have an external lamina and reticular fibers and are surrounded by endoneurium. Multiple nerve fibers bundle into a fascicle, and fascicles form nerve.

Front 37

Endoneurium

Back 37

Produced by the Schwann cell. Surrounds a neuron fiber

Front 38

Fascicle

Back 38

Bundle of multiple nerve fibers

Front 39

Perineurium

Back 39

Sheath of nerve fiber fascicles - made of concentric layers of perineurial cells. Connected by tight junctions -fibro-epitheloid cells and endothelial cells form blood-nerve barrier

Front 40

Epineurium

Back 40

Sheath of dense irregular connective tissue with collagenous and elastic fibers that can wrap around multiple nerve fascicles

Front 41

Dura mater

Back 41

Fibrous connective sheath. Epidural space between bone and dura contains venous sinuses draining cerebral veins

Front 42

Arachnoid

Back 42

Avascular with trabeculae connecting dura to pia. Lined by mesothelium and has CSF

Front 43

Pia mater

Back 43

innermost vascularized CT layer adjacent to brain and spinal cord

Front 44

CSF volume

Back 44

150 mLs static, with 450-550 mLs produced per day

Front 45

CSF function

Back 45

cushion brain and maintain suitable environment via diffusion of metabolites and small solutes flowing down spinal cord canal

Front 46

Telencephalon

Back 46

Cerebrum. Forebrain. Two hemispheres covered by cerebral cortex with lateral ventricles with CSF. Has lobes.

Front 47

Diencephalon

Back 47

Thalamus and hypothalamus - divided in half by third ventricle

Front 48

Mesencephalon

Back 48

Midbrain. Traversed by cerebral aqueduct that connects third and fourth ventricles

Front 49

Metencephalon

Back 49

Cerebellum and pons. Fourth ventricle

Front 50

Myelencephalon

Back 50

medulla oblongata - continuous with spinal cord. Fourth ventricle is continuous with spinal canal

Front 51

Brainstem

Back 51

Medulla oblongata, pons, and mesencephalon. Regulates involuntary repsonses.

Front 52

Layers of cerebrum

Back 52

Molecular
External granular
External pyramidal
Internal granular
Internal pyramidal
Multiform

Front 53

Layers of Cerebellum

Back 53

Molecular
Purkinje
Granular