Nervous & Central Nervous System

what is the function of the Nervous System?

to maintain homeostasis, coordinate body function, enable interaction with the enviroment

Absorption of this ion is necessary for the presynaptic cells to release a neurotransmitter. 

calcium

What are the mechanisms for removing the excess of a neurotransmitter in a synapse?

broken down by enzymes, uptake by the presynaptic neuron, diffusion away from the synaptic cleft and taken up by astrocytes

what are the two major functional divisions of the nervous system?

sensory division, motor division

what is the function of Neuroglia cells?

nourish, support, protection, maintaining interstitial fluid, undergo mitosis

What are Neurons?

communication cells of nervous system and requires ATP to function

what are the neuroglia cells of the CNS?

astrocytes, microglia, ependymal cells, oligodendrocytes

what is the function of astrocytes?

maintain the blood brain barrier and ion concentration in interstitial

what is the function of microglia cells?

specialized macrophages that present antigen to the immune system

what is the function of ependymal cells?

assist in the synthesis and movement of cerebrospinal fluid

what is the function of Oligodendrocytes?

myelinates multiple axons

what are the neuroglia of the PNS?

satellite cells, Schwann cells

what is the function of satellite cells?

regulate ion centration and exchanges with capillaries

what is the function of Schwann cells?

forms the myelin sheath around single axon segment in the PNS

what part of a neuron contains gray matter?

the soma

what is the function of dendrites?

receives messages

what is the function of the Axon hillock?

connects signals and connects dendrites to axons

what is the function of axons?

where messages travel

what is the function of the Axon terminal?

where messages are passed along to another cell

multipolar structural neuron

many processes extend from the cell body

where are multipolar structural neurons located?

throughout the CNS and autonomic ganglia

bipolar structural neuron

two processes of a fused dendrite and an axon

unipolar (pseudounipolar) structural neuron

one process extends from the cell and forms central and peripheral processes

what is the function of sensory (afferent)neurons?

carries information away from a receptor towards the CNS

what is the function of interneurons?

relay sensory information

what is the function of motor (efferent) neurons?

carries directions away from the CNS towards the effectors

what are most multipolar neurons classified as?

interneuron

Bipolar neurons are classified as?

sensory neurons

what are most unipolar neurons classified as?

sensory neuron

what is resting membrane potential?

electrical charge generated across the membrane typically -70 mV

what is threshold potential?

the voltage needed to trigger an action potential

what is the threshold value?

-55mV

what happens during depolarization?

sodium channels open and sodium rushes in making the cell more positive

what happens during repolarization?

potassium exits the cell and makes it negative

what part of the neuron does action potential takes place in?

axon hillock

what is the absolute refractory period?

a period where no action potential can be generated

what is relative refractory period?

a new action potential can be generated only if there is a strong stimulus

what is continuous conduction?

occurs in unmyelinated axons and slower

what is saltatory conduction?

electrical signal is refreshed at the nodes of Ranvier

what is the role of calcium at axon terminals?

triggers neurotransmitter release via exocytosis

what is the function of presynaptic neuron?

releases neurotransmitter

what is the function of postsynaptic neuron

receives neurotransmitters

what is an excitatory neurotransmitter?

bind to ligand gated channels and causes an excitatory postsynaptic potential depolarizing membranes

what is an Inhibitory neurotransmitter?

bind to ligand Cl channel and hyperpolarizing cell membrane

what is a summation?

the process where signals add together

what is a temporal summation?

occurs when all of the messages are coming from one presynaptic neuron

what is spatial summation?

occurs when the message come from multiple presynaptic neuron

what is the function of inotropic receptors?

used to change the membrane potential of postsynaptic neuron

what is a metabotropic receptor?

G protein coupled receptor which can alter gene expression

what is serial processing?

occurs when sensory information follows a single pathway

what is parallel processing?

sensation triggers multiple pathways

what is neuroplasticity?

the ability of the nervous system to change and adapt through learning and memory

Why can the central nervous system not be repaired?

prevention by oligodendrocytes, lack of growth factor, astrocytes make scar tissue

why can the PNS regenerate better than the CNS?

Schwann cells assist in repair

What are the 7 main structure of the central nervous system?

cerebrum, diencephalon, midbrain, pons, medulla oblongata, cerebellum, spinal cord

what is the difference between gray and white matter?

gray matter is made of cell bodies while white matter is mostly myelinated axons

what are the protective structures of the central nervous system

cranial and facial bones, meninges

what is the dura mater?

outer and toughest layer of the meninges

what is the Arachnoid mater?

middle layer with spider web extension filled with CSF

what is the pia mater?

inner layer of the meninges

what does the blood-brain barrier do?

regulates movement of molecules into the brain

what are the functions of cerebrospinal fluid (CSF)?

cushions and reduce weight of brain, protection from trauma, nourish brain

what structure in the brain produces CSF?

choroid plexus in the ventricles

what are the 5 lobes of the cerebrum?

frontal, parietal, temporal, occipital, insula

what are the major dividing structures in the cerebrum?

longitudinal fissure, central sulcus

what is the function of the central sulcus?

divides the frontal and parietal lobe

what is the cerebral cortex?

the outer layer of gray matter that acts as our conscious mind

what is the function of the precentral gyrus?

houses the primary motor cortex which initiates voluntary movement

what is the function of the postcentral gyrus?

houses the primary somatosensory cortex which receives sensory input

the map of the body that is found in the postcentral gyrus is known as?

sensory homunculus

the motor map of the body that is found in the precentral gyrus is known as?

motor homunculus

what part of the brain controls speech?

the left hemisphere

what does Broca’s area do?

converts thoughts into word

what is the function of Wernicke’s area?

interprets spoke, written, or signed speech

what are Association tracts?

connects areas in the same cerebral hemisphere

what are commissural tracts?

connects areas in opposite hemispheres

what are projection tracts?

sends information out of the brain

what are the basal nuclei?

groups of gray matter in the middle of the white matter of the cerebrum

what are the functions of the basal nuclei?

suppress unwanted movement, filter out unnecessary responses

which disorders are associated with basal nuclei?

Parkinson’s disease, Tourette’s syndrome

what is the function of the thalamus?

relay center for sensory, motor and filters information

what is the major functional region of the epithalamus?

pineal gland

what is the function of the pineal gland?

produce melatonin needed to regulate sleep cycle

what is the function of the hypothalamus?

maintain homeostasis, growth, metabolism, temperature

what is the function of the hippocampus?

stores memories

what is the function of the olfactory bulb

triggers emotional responses to smells

what is the function of the amygdala?

regulates fear and rage responses

what is the function of the cingulate gyrus?

enables the use of gestures to express emotions

what is the function of the superior colliculi in the midbrain?

assists with visions

what is the function of the inferior colliculi in the midbrain?

assist with hearing

what is the function of the pons

relays motor information, regulates breathing, controls urination

what is the function of the medulla oblongata?

regulates many basic life functions

what is the reticular formation?

group of neurons throughout the brainstem that control consciousness

what is the function of the reticular activating system (RAS)?

maintains consciousness, activated by sensory input

what is the function of the cerebellum?

coordinates movement, balance and posture

inferior peduncle

brings information from the medulla and spinal cord into the cerebellum

middle peduncle

brings information from the pons to the cerebellum

superior peduncle

sends edited motor plans to the primary motor cortex

what is the function of the spinal cord?

allows two-way communication between the brain and the rest of the body

what are the two enlarged areas containing more neurons that serves the appendages?

cervical and lumbar