Nervous System Ch 10.3 DAT

Neuron

functional unit of the nervous system

soma

the nucleated segment of the neuron

dendrites

signal receptor segment of the neuron

axon

signal transferring segment of the neuron

myelin sheath

fatty insulation that covers most of the axon and prevents ion exchange from occurring prematurely

oligodendrocytes

components of the myelin sheaths in the central nervous system

schwann cells

components of myelin sheaths in the peripheral nervous system

nodes of ranvier

gaps in the myelin sheath where ion exchange may occur

jumping

action potentials can be accelerated down the axon by ____ from node to node

axon hillock

location where graded potentials summate, and connect the axon to the body

action potential

Rapid change in the membrane potential that exists across a

-70 mv

Resting potential for a neuron is about

Sodium and pottasium

Resting potential is maintained by active transport of _____

stimuli

action potentials are triggered in neurons by____

depolarization

If the stimuli brings the action potential to the threshold potential then _______may occur

-55 mv

Threshold potential for a neuron is

Sodium, closed

Depolarization is the beginning of an action potential where _____ ions flow back into the cell and potassium channels are _____

repolarization

when the potassium channels open

negative

repolarization causes the membrane potential to become more ____ are reapproach to -70 mv

hyperpolarization

potassium channels stay open past resting potential causing ____

Na/K ATPases

reset the membrane potential after hyperpolarization

absolute refractory period

last from depolarization through repolarization, no new action potential can be triggered

relative refractory period

exists beyond repolarization, it is very difficult to trigger a new action potential here but it is possible

Synaptic transmission

begins with the conclusion of the action potential at the axon terminal

pre synaptic membrane

depolarization opens voltage gated channels, allowing large amounts of Ca 2+ into the presynaptic cleft

exocytosis

the high concentration of calcium in the cell causes _____ of Neurotransmitters via synaptic vesicles

synaptic vesicles

openings in the pre synaptic cleft that allow for the expulsion of neurotransmitters

ligand gated ion

the neurotransmitters cross the synaptic cleft, binding to the ______ channels on the post synaptic membrane

inhibitory or excitatory

the binding of neurotransmitters to the post synaptic ligan gated ion channels can either have a ____ or ____ postsynaptic graded potential

axon hillock

all newly formed graded potentials will summate at the ____

neuron threshold

if the summate at the axon hillock reaches the ______, then the action potential is passed along

glutamate

main excitatory neurotransmitter of the central nervous system, a type of catecholamines

Excitatory Neurotransmitters

dopamine, epinephrine, norepinephrine

Acetylcholine

Excitatory neurotransmitter responsible for the muscular system

GABA

main inhibitory neurotransmitter of the central nervous system

Inhibitory Neurotransmitters

Glycine and Serotonin

Forebrain, Midbrain, and Hindbrain

three main categories of the early development of the brain

telencephalon and diencephalon

Forebrain develops into these secondary structure in five week development

cerebrum

the telencephalon develops into the

thalamus, hypothalamus and pineal gland

the diencephalon develops into the

mesencephalon

the midbrain develops into this secondary structure during five week development, which then gives rise to a fully developed midbrain

metencephalon and myelencephalon

the hindbrain gives rise to these secondary structures during five week development of the brain

pons and cerebellum

the metencephalon gives rise to these final structures

medulla oblongata

the myelencephalon gives rise to this final structure

cerebral cortex

responsible for higher order functions, comprised of the frontal love, occipital lobe, temporal lobe, and parietal lobe

frontal lobe

a part of the cerebral cortex that is responsible for higher level functioning

temporal lobe

a part of the cerebral cortex that is responsible for speech and hearing

occipital lobe

a part of the cerebral cortex that is responsible for vision

parietal lobe

a part of the cerebral cortex that is responsible for spatial perception and sensation

cerebellum

part of the brain that controls body movement

brainstem

responsible for automatic functions, includes the midbrain, pons, medulla oblongata, and is supported by the reticular formation

midbrain

a part of the brainstem that is responsible for relay of senses

pons

a part of the brainstem that is responsible for the relay of messages between the forebrain, cerebellum, and medulla

medulla oblongata

a part of the brain stem that is responsible for controlling heart rate, breathing rate, blood pressure, and sensing toxins

reticular formations

neurons that exist throughout the brain stem that are responsible for cortical arousal and consciousness

limbic system

responsible for emotion, memory, learning, and motivation

thalamus

a part of the limbic system that is the relays sensory and motor signals and is located between the cerebrum and the midbrain

hypothalamus

a part of the limbic system that is responsible for regulation of hormone secretions

hippocampus

a part of the limbic system that is responsible for memory

amygdala

a part of the limbic system that is responsible for emotional reactions to scents

spinal chord

connects the brain to the body

afferent nerves

relay signals from the body to the brain via the spinal chord and dorsal roots

efferent nerves

relay signals from the brain to the body via ventral roots

Somatic nervous System

involved in voluntary motor action, skeletal muscles

autonomic nervous system

involved involuntary processes

peripheral

the autonomic nervous system, somatic nervous system, motor and sensory neurons are all a part of the ______ nervous system

sensory neurons

mechanoreceptors, nociceptors, thermoreceptors, chemoreceptors, and electroreceptors

mechanoreceptors

responsible for the reception of mechanical stimuli

nociceptors

responsible for reception of pain stimuli

thermoreceptors

responsible for reception of stimuli related to changes in temperature

chemoreceptors

responsible for reception of chemical stimuli

electroreceptors

responsible for reception of light, electrical, and magnetic stimuli

autonomic nervous system

comprised of the sympathetic and parasympathetic nervous systems

sympathetic nervous system

induces fight or flight

parasympathetic system

calms the body down from a sympathetic state, inducing rest and digest

ganglion

a cluster of PNS neuron cell bodies

postganglionic

______ neurons extend from the ganglion to the effector organ

preganglionic

______ neurons extend from the CNS to the ganglion

parasympathetic

the ______ nervous system has long preganglionic neurons and short postganglionic nervous systems

sympathetic

the ______ nervous system has short preganglionic neurons and long postganglionic nervous systems

adrenal

the sympathetic nervous system can stimulate the _____ medulla to release the epinephrine or norepinephrine into the blood stream

acetylcholinesterase

an enzyme that hydrolyzes acetylcholine

outer, middle and inner ear

three parts of the ear

outer ear

receives sounds and relays them to the middle ear

bony ossicles

located in the middle ear, transmit and amplify the sounds vibrations from the outer ear to the inner ear

inner ear

begin to transform sounds waves into electrical impulses using fluid filled sacs

cochlea

uses fluid and hairs to convert mechanical signals into neural signals known as transduction, relies on the round window to expand

semicircular canal

one of the fluid filled sacs in the inner ear that is responsible for conveying information about movement, ex: dizziness

tympanic membrane

ear drum, transfers sounds vibrations from the outer ear to the inner ear

cornea

responsible for focusing light and protecting the eye

iris

controls the size of the pupil, eye color, and within the cornea

pupil

controls the amount of light that enters the eye

lens

focuses the relevant image into the eye

retina

located at the back of the eye and contains photoreceptors, rods or cones

rods, cones

_____responsible for vision in low light, ____ are responsible for color perception

fovea

retinal region with the highest amount of photoreceptors

amacrine and bipolar cells

transmits information from the retinal rods and cones to the ganglion cells and the optic nerve fibers

optic nerve, optic disc

___ is a bundle of axons that transmits visual info to the brain, ___is the brains blind spot where there are no photoreceptors present

sclera, choroid

____ are the whites of the eyes, protective connective tissue, and ___are the vascular connective tissue between the sclera and the retina

olfactory receptor cells

sensory smell molecules send signals to the olfactory cortex, then the thalamus, then the orbitofrontal cortex