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Functions of the nervous system are?

Sensory input, Interpretive functions, Motor output, Higher mental functioning, Emotional responsiveness

There are 2 basic divisions of the nervous system?

Central and peripheral nervous system

Central Nervous System (CNS) Functions?

Interprets sensory info, Initiates motor responses, Center for thoughts & emotions.

CNS major components are

Brain, spinal cord, meninges, cerebrospinal fluid.
All of these are surrounded by bones of the skull and spinal column

Peripheral Nervous System (PNS) cranial nerves exit?

Brain

Peripheral Nervous System (PNS) spinal nerves exit?

Spinal cord

Subdivisions of PNS are?

Somatic nervous system: Voluntary
Autonomic nervous system: Involuntary

PNS has how many pairs of nerves?

43

PNS has how many pairs of cranial nerves?

12

PNS has how many pairs of spinal nerves?

31

There are 2 types of cells of the nervous system?

Neuroglia
Neurons

Neuroglia or glia cell is

Connective tissue that supports, nourishes, protects, insulates and organizes neurons.

Neuroglia cell make up more than?

50% of CNS

Glia cells in the CNS are?

Astrocytes, Ependymocytes, Microglia, Oligodendrocytes

Glia cells in the PNS are?

Schwann cells, Satellite cells

Neurons

Basic impulse-conducting cells possessing specialized properties.

Neuron Properties include?

Excitability, Conductibility, Secretion

Parts of a Neuron?

Cell body (cyton), Dendrites, Axon

Cell Body(cyton)

Contains nucleus and other organelles

Dendrites

Transmits impulses toward cell body

Axon

Transmits impulses from cell body

Structures associated with axons?

Telodendria, Synaptic bulb, Synaptic vesicles

Telodendria

Short filaments on ends of axons

Synaptic bulb

Located at end of telodendria
Contain synaptic vesicles

Synaptic vesicles

Store neurotransmitters

Sensory = afferent

Carry impulses to CNS

Motor = efferent

Carry impulses from CNS

Interneuron = association

Carry impulses between sensory & motor neurons
Perform integrative functions

Nerve Impulses

Electrical signals that convey information along a neuron.

Action Potential

Change in the electrical charge of a neural membrane caused by movement of charged particles (ions)

Action Potential is needed

to conduct an impulse

Polarization

Membrane's resting state not conducting an impulse

Polarization has inside and outside charges what are they?

Inside bears negative (-) charge
Outside bears positive (+) charge

Sodium-potassium pump

Produces & maintains polarization and pumps ions in opposite direction at an unequal rates.

Depolarization

When stimulated, channels open and Na flows into cell. Cell interior changes from (-) to (+)

Depolarization occurs in

segments down length of axon

All-or-none Response

Impulse is conducted along entire neuron at maximum capacity.
Impulse continues until it reaches end of neuron

Repolarization

Membrane quickly becomes impermeable to Na
K channels open
Cell membrane repolarizes

Another term for myelinated axon is?

Fast-conducting nerve fibers

Synapse

The junction between 2 neurons or between a neuron an a muscle or gland. Impulses are transmitted across sysapse by action of neurotransmitters

Synaptic Structures

Synaptic bulb (presynaptic neuron)
Synaptic cleft
Plasma membrane (postsynaptic neuron)

Synaptic bulb (presynaptic neuron)

Located at end of axon
contains neurotransmitters

Synaptic cleft

Space between synaptic bulb and plasma membrane

Plasma membrane (postsynaptic neuron)

Dendrites of postsynaptic neuron contain binding sites for neurotransmitters

Synaptic Transmission

1. Impulse travels down axon to synaptic bulb (neurotransmitters are released)
2. Neurotransmitters cross synaptic cleft
3. Neurotransmitters bind to receptors on plasma membrane of postsynaptic neuron
*Neurotransmitter action does not last long
continuously removed from synaptic cleft by enzymes or reuptake.

Neurotransmitters

Chemical messengers involved in nerve transmission are stored in vesicles and can be either excitatory or inhibitory

Most common neurotransmitter is?

Acetylcholine(ACh)

Other Neurotransmitter are?

Epinephrine & norepinephrine
Serotonin
Dopamine

Central Nervous System (CNS) consists of?

Brain & Spinal cord

Brain & spinal cord are all protected by?

Skull, Vertebral column, Meninges, Cerebrospinal fluid

Brains has 4 main sections?

Cerebrum, Diencephalon, Cerebellum, Brain stem

What is the largest area of the brain?

Cerebrum

Cerebrum contains?

Sensory & motor areas
Language centers
Limbic system (governs many certain emotions)

Cerebral Cortex

Outer region of cerebrum.

Sulci

grooves in the outer later of the cerebral cortex

Fissure

a deep sulcus that separate the cerebrum into lobes.

Gyri

elevated ridge of tissue

Cerebral Hemispheres

Cerebrum contains right and left hemispheres
Longitudinal fissure
Corpus callosum

Longitudinal fissure

Separates hemispheres

Corpus callosum

Transverse fibers connection hemispheres

Right Hemispheres Specialization

Music, Art & spatial relationships, emotional expression

Left Hemispheres Specialization

Language; receptive and expressive
Reasoning and analytical skills such as math

Cerebral Lobes contain 4 they are?

Frontal, Parietal, Temporal, Occipital

Frontal Lobes

Regulates motor output and cognition.
Contains:
Broca's areas - speech production
Prefrontal cortex - where emotion are processed
Precentral gyrus - called primary motor area

Parietal Lobes

Regulates proprioception, reading and taste.
Governs sensory input (mainly skin & muscles)
Contains:
Postcentral gyrus

Temporal Lobes

Contains:
auditory & olfactory areas
Wernicke area - Language comprehension

Occipital Lobes

Visual areas

Consciousness

degree of mental alertness and responsiveness

The 4 levels of consciousness recorded as brain wave patterns are?

Beta, Alpha, Theta, Delta

Beta

Wakeful consciousness & mental activity
REM sleep appears as beta waves

Alpha

Awake & relaxed

Theta

Drowsiness & dreamlike awareness
used in hypnosis to access deep-rooted memories

Delta

deep sleep from which the subject is not easily aroused

Diencepholon is located in

the center of the brain

Thalamus

nearly 80% of diencephalon
Relays sensory information to appropriate part of cerebrum

Hypothalamus

Regulates ANS and endocrine system
Controls hunger and thirst, anger and aggression, hormones, sexual behavior and sleep patterns

Pituitary Gland

Sits in sella turcica of sphenoid bone

Pineal Gland

Located below corpus callosum

Cerebellum is located?

posterior and inferior to cerebrum

Cerebellum regulates?

muscle tone, posture, balance

Brainstem is continuous with

the spinal

There are 3 main divisions of the Brainstem

Mid-brain
Pons
Medulla oblongata

Mid-brain

conducts impulses from cerebrum to pons
conducts impulses from spinal cord to thalamus

Pons

bridges cerebellum and cerebrum with spinal cord

Medulla oblongata is located?

inferior portion of brainstem

Medulla oblongata

conducts sensory & motor impulses between brain & spinal cord

Medulla oblongata contains?

Respiratory center
Cardiovascular center
Vasomotor center

This contains may crossing over fibers called Decussation

Medulla oblongata

Blood-Brain Barrier

Semipermeable wall of blood capillaries. Prevents or slows passage of some chemicals and pathogens from blood into CNS

This has thick basement membrane and glial cells

Blood-Brain Barrier

Spinal Cord

Exits skull via foramen magnum and is known as the information highway and a integrating center.

Cauda Equina

lower portion of cord shaped like a horse tail

Filum terminale

Fibrous extension of cauda equina

A cross section of the spinal cord reveals this?

White matter located on periphery and Gray matter located in center(H-shaped)

Gray matter in H contains 3 regions called horns?

Anterior horn
Lateral horn
Posterior horn

White matter found in the spinal cord is called

Columns

There are 3 columns in the spinal cord column?

Anterior column
Lateral column
Posterior Column

Tracts

Collection of nerves running up and down spine

There are types of tracts

Ascending - Sensory (afferent) impulses travel up cord
Descending - Motor (efferent) impulses travel down cord

Meninges

connective tissue coverings surrounding brain and spinal cord. It has 3 layers

Meningeal layers are?

Pia Mater, Arachnoid, Dura mater

Pia Mater

Innermost delicate layer
attaches to brain and spinal cord

Arachnoid

Middle later resembling a spider's web

Dura mater

Outermost dense layer
lies against skull and spinal column

Meningeal spaces

Subarachnoid, Subdural, Epidural

Cerebrospinal Fluid

Fluid circulating around brain and spinal cord

Functions of the Cerebrospinal Fluid

Supplies O2 and nutrients, Carries away wastes, Acts as a shock absorber

Cranial nerves

Arise from brain
12 pairs

Spinal nerves

arise from spinal cord
31 pairs

CN V(5) Trigeminal

contains 3 branches; pain, temperature and motor innervation for muscles of mastication.

CN VII(7) Facial

Facial expression and produces both saliva and tears.

CN X(10) Vagus

Receives sensations from external ear and external auditory canal and thoracic and abdominal organs. Aids digestion. Regulates heart activity

Nerve Roots

part of spinal nerve that connects to spinal cord.

2 types of nerve roots

Ventral (anterior)
Dorsal (posterior)

Gaglion

Cluster of nerve cell bodies in PNS

Nerve Plexuses

Network of intersecting nerves in PNS

There are 3 major plexuses?

Cervical, Brachial, Lumbosacral

Dermatomes

Area of skin supplied by specific sensory nerve root

Reflexes

Involuntary, predictable response to a stimulus

Reflex arc

carries stimulus to spinal cord
connects motor neuron to appropriate muscle or gland

Autonomic Nervous System has 2 divisions?

Sympathetic & Parasympathetic

Parasympathetic Nervous System

Supports functions that conserve & restore energy - (Maintains homeostasis and regulates urinary & digestive processes, pooping and storing nutrients)

Most active under calm conditions

Referred to as craniosacral outflow

Sympathetic Nervous System

Uses body energy for periods of physical exertion or emotional stress

Adrenals secrete ephinephrine

Referred to as thoracolumbar outflow

Called "fight-or-flight

Sympathetic Nervous System

Law of Facilitation

When an impulse has passed once through a certain set of neurons to the exclusion of others, it tends to take the same course of future occasions and each time it traverses this path the resistance is less.

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