Nervous system

The nervous system is divided into two parts: ________ and _________.

Central nervous system ; Peripheral nervous system

2 parts of Central nervous system (CNS)

1. Brain
2. Spinal chord

3 parts of Peripheral nervous system (PNS)

1. Cranial nerves
2. Spinal nerves
3. Ganglia

How do cells communicate in the nervous system?

Cells communicate via electrical and chemical signals that are fast and specific, causing immediate changes.

response to stimulation

excitability

electrical impulses propagated between cells

conductivity

large cells, impulse propogation

neurons

smaller cells that support neurons and act as nervous glue

neuroglia

Provides structural and metabolic support to neurons

neuroglia

Neurons that bring impulses out of the CNS to muscles

Motor neuron

Membrane receiving neurotransmitters for impulse conduction

Post-synaptic membrane

Gap in the myelin sheath

Node of Ranvier

Lines ventricles of the brain, produces CSF

Ependymal cells

Region of the CNS with fully myelinated axon fibers

White matter

Nervous system cells that transmit electrical impulses

Neurons

Most common glial cell, makes myelin in the CNS

Oligodendrocytes

Clustered ribosomes and RER, soma looks grainy

Nissl bodies

Neurons bringing sensations into the CNS for processing

Sensory neurons

Waxy, lipid-based wrapping around an axon

Myelin sheath

Produce myelin sheaths in the PNS

Schwann cells

Also called the soma

Cell body

Neuron having one dendrite and one axon

Bipolar

Neurons having many dendrites

Multipolar

Conducts electrical current into the soma

Dendrite

Neurons that integrate afferent & efferent impulses in CNS

Interneurons

afferent impulse

entering, travel from sensory organs/receptors to the central nervous system

efferent impulse

exiting, travel from the CNS to the organs/ glands

Site of neurotransmitter production

Nucleus

Chemicals released by neurons to stimulate other cells

Neurotransmitter

Conducts impulses away from the soma

Axon

Region of the soma without Nissl bodies leading to the axon

Axon hillock

Region of the CNS with non-myelinated axon fibers

Grey matter

Neuron having one projection acting as dendrite and axon

Unipolar

Star-shaped cells forming the blood-brain-barrier

Astrocyte

Junction or point of close contact between two neurons

Synapse

Membrane emitting neurotransmitters into the synapse

Pre-synaptic membrane

Cerebrum lobe that processes olfaction and auditory stimuli.

Temporal lobe

Grey matter region in spinal cord connecting R&L horns

Grey commissure

White matter in cerebellum, distinct tree-like pattern

Arbour vitae

Unmyelinated axons; spinal cord arranged into horns.

Grey matter

Skin innervated by single spinal nerve branch; mapped

Dermatomes

Speech comprehension processed here; left temporal lobe.

Wernecke’s area

Peripheral NS part; involuntary visceral motor control.

Autonomic nervous system

Clusters of ependymal cells inside the brain ventricles; CSF

Choroid plexus

Thin strand of pia mater, anchors conus medullaris to coccyx.

Filum terminale

Oval masses; sensory input relay station (except olfaction)

Thalamus

PNS branch; voluntary somatic motor control of skeletal muscle

Somatic nervous system

Cerebrum lobe processes vision and retains visual memories.

Occipital lobe

Hidden inner lobe of cerebrum; processes taste and memory

Insula

Speech production controlled here; left frontal lobe.

Broca’s area

ANS branch, speeds up activity for fight or flight response.

Sympathetic division

Connective tissue surrounding a nerve fascicle

Perineurium

Epithalamus; secretes melatonin for sleep cycles

Pineal gland

Tapered end of the spinal cord, ends around L1/L2.

Conus medullaris

Cervical plexus nerve controlling the diaphragm

Phrenic nerve

Inferior spinal nerve axons, branches off conus medullaris.

Cauda equina

ANS branch, conserves energy during rest and digest times.

Parasympathetic division

Astrocyte perivascular feet regulate diffusion into the brain

Blood-brain barrier

Innermost, thin, delicate layer of the dural meninges

Pia mater

Walls of 3rd ventricle; controls body homeostasis functions.

Hypothalamus

Large, superior region of brain; lobes; somatic & motor

Cerebrum

Irregularly shaped brain spaces filled with moving CSF.

Ventricles

C-shaped white matter, connects R&L cerebral hemispheres

Corpus callosum

Cranial meninges separating cerebrum & cerebellum.

Tentorium cerebelli

CN X; controls most of the major organs of the body; mixed

Vagus nerve

CN I; controls sense of smell.

Olfactory nerve

CN II; controls vision.

Optic nerve

CN III; allows movement of the eye muscles, constriction of the pupil, focusing the eyes and the position of the upper eyelid.

Oculomotor nerve

CN IV; enables movement in the eye's superior oblique muscle

Trochlear nerve

CN V; provides sensation to the face, and is responsible for motor functions like chewing and biting.

Trigeminal nerve

3 branches of the trigeminal nerve

V1 - Ophthalmic branch
V2 - Maxillary branch
V3 - Mandibular branch

CN VIII; has branches for balance and sound detection.

Vestibulocochlear nerve

CN VI; controls the movement of the lateral rectus muscle.

Abducens nerve

CN VII; control facial movement and expression, carries nerves that are involved in taste to the anterior 2/3 of the tongue.

Facial nerve

What are the 5 branches of the facial nerve?

- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
* Two Zombies Bit My Children *

CN XI; neck and shoulder movement, specifically the sternocleidomastoid and trapezius muscles.

Accessory nerve

CN XII; tongue muscles for swallowing and speech.

Hypoglossal nerve

cluster of nerves

plexus

most distal portion of a neuron’s axon and is critical for neural communication

axon terminal button

precursors to skeletal muscle cells and are responsible for the ability of muscle tissue to regenerate; PNS

satellite cell

immune cells of the CNS

microglia

What are the 4 types of neuroglial cells in the CNS

- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal

What two types of neuroglial cells are in the PNS?

- Satellite cells
- Schwann cells

Deeper tissue of nerve fibers in the brain

White matter

Superficial, outermost tissue of neuronal cell bodies and unmyelinated axons in the brain

Grey matter

99% of neurons are what type?

Multipolar interneurons

Biggest nerve in body

sciatic nerve

macroscopic, cable-like bundles of parallel axons

nerves

nerve type that senses changes in sensory receptors

sensory

nerve type that reacts to changes in sensory receptors through effectors

motor

two types of effectors

muscles and glands

what nerve type are most nerves?

mixed

a cluster of neurons in the spinal nerve that carry sensory messages from receptors at the periphery towards the central nervous system for a response

dorsal root ganglion

dense sheath of irregular connective tissue covering a nerve

epineurium

layer of fat cells beneath the epineurium in a nerve

perineurium

a layer of delicate connective tissue around the myelin sheath of each myelinated nerve fiber in the PNS

endoneurium

anterior / ventral direction of the brain

rostral

posterior / dorsal direction of the brain

caudal

division of the ANS that mobilizes body systems during activity; fight or flight

sympathetic division

division of the ANS that conserves energy and promotes house-keeping functions during rest

parasympatheic division