Human Anatomy ZOO 3731: Nervous Tissue, Spinal Cord and Nerves, and Brain and Cranial Nerves

Endorphins

"endogenous morphine= morphine within"—natural, opiate-like neurotransmitters linked to pain control and to pleasure. causes sleepiness and relaxation

cauda equina

"horse's tail", a fan of nerve fibers below the spinal cord spinal nerves below L2 hanging down from the end of the spinal cord

Dermatomes are

- Segment of skin supplied by single spinal nerve -Can help localize damage to one or more spinal nerves -Involved in referred visceral pain

Sensory function of the CNS

-Detect internal/external stimuli -afferent nerve -info of sensation arriving at CNS

folia of cerebellum

-cortical ridges -most transversely oriented -divide the cerebellum into lobes or lobules -equivalent to gyri

Hypothalamis

-main visceral control center -center of homeostasis -temperature control center (sweat or shiver) -behavioral drives (thirst) -part of the brain that also releases hormones -involved in emotions (limbic system- center of emotions) -connects to pituitary gland via infundibulum (links nervous and endocrine systems) -controls hormone release by pituitary gland -neurosecretory cells secretes hormones (ADH - water retention- and oxytocin) to regulate body processes -> ADH and Oxytocin produced in hypothalamus and secreted by pituitary

Gray matter of brain

-mostly on the external/superficial/outside (cerebral cortex) -basal ganglia and cranial nerve nuclei are internal composed of neuronal cell bodies

Mesencephalon (midbrain)

-processing of sight (visual) and sound (auditory) data -generation of reflexive somatic motor responses (associated reflex- reacting to loud sound from jumping) -maintenance of consciousness -has a role in moving our eyes bc almost all extrinsic eye muscles are innervated by Cranial Nerves that leave mesencephalon

Action potentials flow through an unmyelinated axon at what speed

0.5 m/s

How many coccygeal nerves?

1 coccygeal nerve

Diencephalon subdivided into 3 portions:

1. Epithalamus 2. Thalamus 3. Hypothalamus

diencephalon divisions

1. Epithalamus 2. Thalamus 3. Hypothalamus

3 main ways of getting rid of neurotransmitters inside synaptic cleft

1. NT can be recycled and go back into synaptic cleft 2. Enzymes can degrade NTs 3. NT can diffuse into tissue fluid thats nearby

Neuroglia of PNS

1. Satellite cells 2. Schwann cells (neurolemmocytes)

Neuroglia of CNS

1. astrocytes (most numerous, provide physical and nutritional support and make up Blood Brain Barrier) 2. microglial cells (phagocytosis of damaged nervous tissues and pathogens), 3. ependymal cells (lines inner surfaces of ventricles and central canal of spinal cord, secrete Cerebrospinal fluid (CSF) and have cilia involved with directionality), 4. oligodendrocytes (make myelin sheaths in CNS with multiple branches, inhibit regeneration of axons by forming scar tissue over damage)

major regions of the brain

1. cerebrum, 2. diencephalon (thalamus and hypothalamus), 3. brainstem (mesencephalon, pons, medulla oblongata), 4. cerebellum

Sacral Plexus (L4-S4)

1/2 L4, S1, S2, S3, S4 Pudendal Nerve Sciatic Nerve Tibial Nerve Common Fibular Nerve Deep and Superficial Fibular Nerves

Brachial Plexus (C5-T1)

1/2 of C5, C6, C7, C8, T1 Subunits of Brachial Plexus: Roots, Trunks, Divisions, Cords, Branches To remember subunits of brachial plexus: Always Remember To Drink Cold Beer (Anterior Ramus, Roots, Trunks, Divisions, Cords, Branches) C7 gives rise to middle trunk C5 & C6 gives rise to superior trunk C8 & T1 gives rise to inferior trunk Posterior division of each trunk form Posterior Cord Anterior division of superior and middle trunk give rise to Lateral Cord Anterior division of inferior trunk gives rise to Medial Cord Posterior Cord gives rise to Axillary and Radius Nerves (Branches) Lateral Cord and Medial Cord gives rise to Median Nerve Medial Cord gives rise to Ulnar Nerve

How many thoracic nerves?

12 pairs (T1-T12)

How many pairs of cranial nerves are there?

12 pairs of cranial nerves

Action potentials flow through myelinated axons at what speed

130 m/s

How many pairs of spinal nerves are there?

31 pairs of spinal nerves

How many lumbar nerves?

5 pairs (L1-L5)

How many sacral nerves are there?

5 pairs (S1-S5)

How many cervical nerves are there?

8 pairs (C1-C8)

____ % od CSF flows out thru apertures into subarachnoid space but 10% CSF flows thru central canal

95

Pons

A brain structure that relays information from the cerebellum to Cerebrum (middle cerebellar peduncle) -plays a role with cerebellum in coordinating skeletal muscle activity -has a role in breathing patterns, it modulates respiratory reflex centers in medulla oblongata

Choroid plexus

A highly vascular portion of the lining of the ventricles that secretes cerebrospinal fluid. surrounded by ependymal cells (produce CSF)

myelin sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next. creates insulation

bipolar neurons

A neuron that has only two projections (one axon/one dendrite) from the cell body sensory neurons for special senses only

unipolar neuron

A neuron with one axon attached to its soma; the axon divides, with one branch receiving sensory information and the other sending the information into the central nervous system. aka pseudounipolar neurons sensory neurons for general senses found in dorsal root ganglion

Frontal Lobe

A region of the cerebral cortex related to voluntary control of skeletal muscles, abstract thinking, problem solving, planning, reasoning, and judgement

occipital lobe

A region of the cerebral cortex that processes visual information; perception of visual stimuli

Parietal Lobe

A region of the cerebral cortex whose functions include processing information about touch. related to sensations

Reflex Arc

A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus, often without conscious brain involvement.

sodium-potassium pump

A special transport protein in the plasma membrane of animal cells that transports 3 sodium out of the cell and 2 potassium into the cell against their concentration gradients.

Axon

A threadlike extension of a neuron that carries nerve impulses away from the cell body.

CN VI

Abducens Nerve

CN XI

Accessory Nerve

Neurotransmitter that is both excitatory and inhibitory? Where is it found? Where does it have an excitatory effect? Where does it have an inhibitory effect?

Acetylcholine (ACh) Found in neuromuscular junction Excitatory effect in skeletal muscle; when somatic motor neurons bind in skeletal muscle it makes them contract Inhibitory effect when released by Autonomic Motor neurons like when reaching cardiac muscle cells, it makes heart beat slower

temporal lobe

An area on each hemisphere of the cerebral cortex near the temples that is the primary receiving area for auditory information and olfactory information

Resting Membrane potential

An electrical potential established across the plasma membrane of all cells by the Na+/K+ ATPase and the K+ leak channels. IN most cells, the resting membrane potential is approximately -70 mV with respect to the outside of the cell.

Integrative function of CNS

Analyze and interpret sensory info. to allow for proper decision making to produce an appropriate response

Brachial Plexus (C5-T1) Nerves

Axillary Nerve Musculocutaneous Nerve Radial Nerve Median Nerve Ulnar Nerve

Calcium channels

Axon terminal, Release of neurotransmitter ligand-gated channels

Median Nerve

Brachial Plexus; goes down in middle of arm and forearm; innervates muscles in anterior aspect of forearm and small portion of hand

Musculocutaneous Nerve

Brachial Plexus; innervates coracobrachialis, biceps brachii, and Brachialis (anterior aspect of arm)

Ulnar Nerve

Brachial Plexus; runs down Ulna bone (medial); main nerve innervating our hands and little portion of the anterior and medial aspect of forearm

Radial Nerve

Brachial plexus; runs down arm and forearm on radius bone (lateral); innervates posterior aspect of arm and forearm

CSF found in

Brain Ventricles Arachnoid Space (brain & spinal cord) Central Canal of spinal cord

CNS consists of

Brain and Spinal cord

gray matter

Brain and spinal cord tissue that appears gray with the naked eye; consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons.

Thalamus

Brain's relay station of sensory information- 95% sensory info goes to thalamus (not smell) largest nuclei in the CNS the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

Cervical Plexus (C1-C5)

C1-C5 (1/2 of C5) originate in anterior ramus of spinal nerves supplies neck, superior part of shoulder and chest phrenic nerve arises from C3, C4, C5, innervates diaphragm break c4, breathe no more

Cranial Nerves that innervate the eyes

CN III (Oculomotor), CN IV (Trochlear), and CN VI (Abducens) Mnemonic: "3, 4, 6 let your eyes do tricks"

Nervous System divided into:

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

BBB absent at:

Choroid Plexus (have capillary endothelial cells and ependymal cells but do not have astrocytes) Hypothalamus (receptors to sense chemical content of blood) Pituitary Gland (major endocrine gland release hormone ADH and oxytocin directly in blood stream) Pineal Gland (endocrine gland releases Melatonin into bloodstream)

superior cerebellar peduncle

Communicates cerebellum with mesencephalon, diencephalon, and cerebrum (superior aspect of cerebellum)

Vermis

Connects the two hemispheres of the cerebellum (R and L)

Epineurium

Dense connective tissue that surrounds entire nerve including fascicles and blood vessels. group of perineurium together invaginates and goes in between perineurium in which we find blood vessels to nourish spinal nerve

lateral white column

Description: lateral part of white matter function: tissue through which messages pass between different areas of gray matter

posterior white column

Description: posterior part of white matter on spinal cord Function: tissue through which messages pass between different areas of gray matter

Motor neurons also called

Efferent neurons (E=Exiting)

dura septa

Extensions of the dura mater that separate parts of the brain (Falx cerebri, tentorium cerebelli, falx cerebelli) folds subdivide cranial cavity and support brain and limit brain movement

CN VII

Facial Nerve

CN VII Facial Nerve

Function: -Sensory: taste, anterior 2/3 tongue -Motor: facial muscles, lacrimal gland, submandibular and sublingual glands, facial expressions , closure of eyelid Controls most (not all) face muscles; this muscle is related to muscles of facial expression To remember which part of tongue it innervates: You can see your face and when you stick out your tongue, you can only see anterior 2/3 of tongue

CN X Vagus Nerve

Function: Sensory and motor function of internal organs; innervates the respiratory, cardiovascular, and digestive organs in thoracic and abdominal cavities -Sensory: sends info from organs (throat, thoracic and abdominal viscera) -Motor: sends information to the organs (vocalization, swallowing, and autonomic control of viscera) LONGEST cranial nerve To remember: "what happens in Vegas, stays in Vegas, but what happens in Vagus goes EVERYWHERE"

CN XI Accessory Nerve

Function: motor function; controls the sternocleidomastoid, trapezius, palate, pharynx, and larynx -Cranial root (medulla oblongata): motor to pharyngeal, laryngeal, and palatal muscles with internal branch -Spinal root (spinal cord): motor to muscles of the superior back - trapezius and sternocleidomastoid with external branch ONLY nerve that has a cranial root and spinal root cranial root comes from medulla oblongata, and spinal root comes from spinal root and has an external branch to the muscles To remember: Think of putting an accessory like a purse on your shoulder/back area

CN IV Trochlear Nerve

Function: motor fxn, controls superior oblique muscles innervated muscle goes thru ligamentous link called trochlea on its way to insertion on super surface of eye aka Pathetic Nerve bc paralysis of nerve caused deviation of eye and cause patient to tilt head to fuse 2 images created by deviated eye giving patient "pathetic look"

CN III Oculomotor

Function: motor fxn: controls extraocular eye muscles - superior, inferior, and medial rectus, inferior oblique, levator palpebrae superioris; intrinsic eye muscles Destination: extraocular eye muscles Nerve that helps eye move but does NOT control superior oblique (trochlear nerve) and lateral rectus (abducens nerve) Helps move upper eyelids and intrinsic eye muscles so change diameter of pupil and shape of lens

CN II Optic Nerve

Function: sensory (vision) Origin: retina Foramen: optic canal Destination: diencephalon, then to occipital lobe responsible for carrying visual info to visual cortex in occipital lobe ONLY CN pair that decussate and splits again in the optic chiasm (superior part of pituitary gland) which allows both sides of brain to receive info simultaneously

CN V Trigeminal Nerve

Function: sensory and motor -Ophthalmic division: sensation from forehead, eyelids and nose -Maxillary division: sensation from lower eyelid, upper lip, gums and teeth, cheek, nose, part of palate, and part of pharynx -Mandibular division: sensory from lower gums, teeth, lip, palate (part), tongue (part); motor to muscles of mastication Destination: -ophthalmic & maxillary: pons -mandibular: muscles of mastication LARGEST of cranial nerves, sensory branch is the largest ophthalmic and mandibular divisions ONLY associated with sensations of the face mandibular division has both sensory and motor functions so involved with voluntary control of muscles of mastication (masseter) so involved with chewing Maxillary -> upper teeth Mandibular -> lower teeth

CN IX Glossopharyngeal Nerve

Function: sensory and motor -Sensory: taste from posterior 1/3 of tongue, baroreceptors (monitor B.P.), and chemoreceptors (detect gas concentrations) -Motor: swallowing (pharyngeal muscles, and parotid salivary glands) Lesion: loss of sensation of upper pharynx; reduced gag reflex; hypertension/hypotension

CN I Olfactory Nerve

Function: sensory function (smell) Innervates: olfactory bulbs ONLY cranial nerve exposed to exterior environment SHORTEST cranial nerve Sensory information from CN I does not pass thru thalamus, it comes in through olfactory bulb straight to cerebrum

CN VIII: Vestibulocochlear Nerve

Function: sensory. balance and hearing balance and equilibrium; hearing comes from our inner ear, the vestibule and cochlea - consists of vestibular nerve and cochlear nerve - vestibular nerve: axons travel to vestibular nuclei of medulla oblongata -cochlear nerve: axons travel to cochlear nuclei of medulla oblongata Lesion: vertigo; nystagmus; vomiting; loss of hearing

CN IX

Glossopharyngeal Nerve

Enteric Nervous System also known as:

Gut-Brain or Second brain; it refers to 2 groups of neurons in Digestive tract known as myenteric plexus and submucosal plexus, which can work independently of our CNS but can communicate with CNS thru parasympathetic and sympathetic divisions of ANS

Elevations in brain called

Gyrus (plural Gyri)

CN XII

Hypoglossal Nerve

Neurogenesis in the CNS

In the CNS, there is little or no repair due to: Inhibitory influences from neuroglia, particularly oligodendrocytes Absence of growth-stimulating cues that were present during fetal development Rapid formation of scar tissue

Purkinje layer of cerebellar cortex

Intermediate layer -intermediate layer -contains Purkinje cell bodies -info from coordinated movements

Lumbar Plexus (L1-L4)

L1, L2, L3, 1/2 L4 Genitofemoral Nerve Femoral Nerve Obturator Nerve

The spinal cord ends at what level?

L1-L2 (conus medullaris)

Flow of CSF through ventricles

Lateral ventricles -> interventricular foramen -> third ventricle -> aqueduct of the midbrain -> fourth ventricle -> lateral apertures or median aperture -> subarachnoid space of brain and spinal cord (central canal) Mnemonic: Flow of CSF is "LIT AF" and if you drive LIT AF, you get into a Car Crash (CC= Central Canal)

Genitofemoral Nerve

Lumbar Plexus; goes to genitals and femoral region (thigh); innervates genital region and upper medial region of thigh

Femoral Nerve

Lumbar Plexus; goes toward femur (thigh); innervates anterior aspect of thigh

Obturator Nerve

Lumbar plexus; goes thru obturator foramen of os coxa and toward medial aspect of thigh; innervates medial aspect of thigh; if contracts-> adduct lower limb

pia mater of the spinal cord

Menix that is in direct contact with the spinal cord. most pliable and flexible, closest to spinal cord

Major source of negativity inside of the cell caused by

Negatively charged proteins

CN III

Oculomotor Nerve

Mnemonic for Cranial Nerves names

Oh Once One Takes The Anatomy Final Very Good Vacations Are Heavenly Oh Oh Oh To Touch And Feel Very Good Velvet, Ah Heaven Only One Of The Two Athletes Felt Very Good Victorious And Healthy Oh Oh Oh To Touch And Feel Virgin Girls Vagina, Actually Heaven Cranial Nerves: Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal

CN I

Olfactory Nerve

CN II

Optic Nerve

Functions of Schwann Cells

Part of the PNS: Produce part of the Myelin Sheath around a single axon of the PNS. Participate in the regeneration of PNS axons.

medulla oblongata function

Part of the brainstem that connects brain and spinal cord -controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion. -relay station b/w spinal cord and rest of brainstem and thalamus (region of diencephalon which 95% sensory info goes to) -has autonomic reflex centers: Cardiac reflex center (regulates heart rate and blood pressure), Respiratory reflex center (regulates breathing rate - which pons can modulate) -leaving medulla is CN X Vagus nerve, which is related to autonomic control of thoracic and abdominal cavities (CV, respiratory, and digestive systems) -regulate basic vital functions

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion. makes the link between our spinal cord and brain

Dura mater subdivided into which layers?

Periosteal layer Meningeal layer

Cranial nerves are part of the

Peripheral Nervous System (PNS)

saltatory conduction

Rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane.

postcentral gyrus of parietal lobe

Receives somatic sensory information (touch, pressure, pain, vibration, taste, and temperature) Primary somatosensory cortex (somatic sensory neurons)

Granular layer of cerebellar cortex

Receptive layer -contains axons of Purkinje cells -tightly packed small neurons that project axons into molecular layer that travel to arbor vitae to cerebellar nucleus to other parts of brain

cutaneous fields

Regions of skin supplied by a specific nerve arising from a plexus

Repolarization

Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.

CN labeled using

Roman numbers and according to position along longitudinal axis inferiorly starting at cerebrum

S1,S2,S3, and S4 spinal nerves exit via the

Sacral Foramen

Pudendal Nerve

Sacral Plexus; S2,S3,S4 goes toward genital area; innervates penis and scrotum in males & clitoris and labia majora and minora and vagina in females

Sciatic Nerve

Sacral Plexus; largest nerve in body; innervates posterior aspect of thigh

Deep and Superficial Fibular Nerves

Sacral plexus; arise from common fibular nerve; innervate anterior aspect of leg

Common FIbular Nerve

Sacral plexus; arises from Sciatic nerve, gives rise to Deep and Superficial Fibular Nerves

Tibial Nerve

Sacral plexus; arises from Sciatic nerve; innervates posterior aspect of leg

Layers of protection of brain: outside to inside

Scalp > Epicranial Aponeurosis (tough layer of dense fibrous CT) > Periosteum of Cranium (vascularized CT involving bone) > skull bones (cranium) > dura mater > arachnoid mater > pia mater

Lateral ventricles separated by a partition called

Septum Pellucidum NO direct connection b/w 2 lateral ventricles

terminal buttons (axon terminals) or synaptic end bulb

Small knobs where axons terminate that secrete chemicals called neurotransmitters

Diaphragma sellae

Smallest of the dural septa Forms a "roof" over the sella turcica (where pituitary sits encased by diaphragma sellae) of the sphenoid bone. A small opening within it allows for the passage of a thin stalk, called the infundibulum, that attaches the pituitary gland to the base of the hypothalamus. anchor dura mater to sphenoid bone

Mnemonic for Cranial Nerves Functions

Some Say Marry Money But My Brother Says Big Brains Matter More S= Sensory M= Motor B = Both sensory and motor

Shallow depressions in brain called

Sulcus (plural sulci); gives us different lobes of brain

Molecular layer of cerebellar cortex

Synaptic layer -most superficial -contains dendrites of Purkinje cells

Axon hillock

The conical region of a neuron's axon where it joins the cell body; typically the region where nerve signals is generated. point of no return

Brainstem

The oldest part and central core of the brain, responsible for automatic survival functions.

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive. loss or reduction of negative membrane potential

Subarachnoid space of brain

The space between the arachnoid and pia mater that contains CSF, trabecular cells, arteries, and veins

visual cortex

The visual processing areas of cortex in the occipital lobe

Thoracic Spinal Nerves T1-T12

These nerves (12 pairs) supply the lateral and anterior part of chest, and parts of the abdomen, including abdominal muscles Do NOT form a plexus Intercostal nerves or thoracic nerves - thoracic nerves run laterally and supple area b/w ribs

dorsal root of spinal nerve

These structures contain the axons of the autonomic sensory neurons.

ventral root of spinal nerve

This structure contains the cell bodies of the somatic motor neurons that innervate the skeletal muscles.

decussate

To cross in the form of an "X" commisure is place where nerve fibers decussate

CN V

Trigeminal Nerve

CN IV

Trochlear Nerve

epidural space of spinal cord

True space Cushion of fat and CT in space between vertebrae and spinal dura mater

Subarachnoid space of brain contains

True space between the arachnoid and pia mater that contains CSF, trabecular cells, arteries, and veins contains projections going into superior sagittal sinus called Arachnoid Granulations or Arachnoid villi

ligand-gated ion channel

Type of membrane receptor that has a region that can act as a "gate" when the receptor changes shape. Neurotransmitters bind to it

CN V Trigeminal Nerve Divisions

V1 - ophthalmic V2 - maxillary V3 - mandibular

CN X

Vagus Nerve

Lateral ventricles

Ventricles located in each cerebral hemisphere. do NOT communicate with each other, they only communicate with third ventricle extend from anterior horn on frontal lobe to inferior horn on temporal lobe, but most of lateral ventricle found in parietal lobe

CN VIII

Vestibulocochlear Nerve

white matter

Whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths (made of fat)

arachnoid mater of brain

a delicate membrane covering the brain and lying between the superficial dura mater and the deeper pia mater that is in contact with the neural tissue of the brain. encloses and protects blood vessels that supply brain

enteric nervous system

a division of the autonomic nervous system consisting of nerve cells embedded in the lining of the gastrointestinal system (GI Tract). It controls secretion and motility within the Gi tract

Action Potential (AP)

a massive momentary reversal of a neuron's membrane potential from about -70 mV to about +50 mV aka nerve impulses

spinal reflex

a reflex controlled at integrating center at the level of the spinal cord that may involve as few as two neurons ex. patellar reflex

Dentrides

a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body. carry signals towards cell body

subarachnoid space

a space in the meninges beneath the arachnoid membrane and above the pia mater that contains the cerebrospinal fluid (CSF)

Sensory neurons also called

afferent neurons (A=Arriving)

when 2 layers of dura mater separate it results in

all dural venous sinuses

Cerebellum lobes

anterior lobe and posterior lobe

all spinal nerves originate in the

anterior ramus of each spinal nerve

third ventricle communicates with fourth ventricle via

aqueduct of midbrain or cerebral aqueduct

If CSF pressure is lower than venous pressure of superior sagittal sinus

arachnoid villi will NOT let blood pass into ventricular system bc arachnoid villi are a one way valve

gustatory cortex

area of the brain inside cerebrum that receives and interprets perception of tastes from the tongue

premotor cortex

area of the frontal cortex, active during the planning of a movement

Axillary Nerve

arises from Posterior Cord of Brachial Plexus; innervates deltoid muscle and teres minor (shoulder)

Dorsal Root Ganglion (DRG)

associated with the dorsal horns; cell bodies of unipolar sensory neurons are located here

Periosteal layer of dura mater of brain

attach to inner surface of skull, closest to bone; ONLY found in brain, not spinal cord Anterior fontanelle of baby

Heart rate, blood pressure, and breathing rate are all under which type of control?

autonomic control

why is there 8 pairs of cranial nerves?

because 1st cervical nerve comes out of spinal cord between the occipital bone and the atlas

subdural space of spinal cord

between dura and arachnoid, contains interstitial fluid

excitatory neurotransmitters

bind to the receptors in postsynaptic neuron and causes ligand-gated channels to open and let Na+ go from outside to inside of cell (depolarization)

inhibitory neurotransmitters

bind with receptors that will allow negative ions, chloride (Cl-) on outside to flow inside and lets K+ leave inside of cell so that cell becomes more negative; inhibitory signal

What do you NOT find in CSF

blood proteins and blood cells (WBC or RBC)

spinal cord is the main communication between

brain and body

ventricles of the brain

canals in the brain that contain cerebrospinal fluid 4 ventricles that form ventricular system

Excitable cells

capable of changing resting membrane potential voltages

Ascending tracts of the spinal cord

carry sensory information to the brain; sensory (afferent) tract

Neuroglia (glial cells)

cells that support and protect neurons Non-neuronal cells that maintain homeostasis can proliferate throughout life 2 types in the PNS and 4 types in the CNS

below fourth ventricle, we have

central canal of spinal cord

Purkinje cells found in? Responsible for?

cerebellar cortex (gray matter) coordinated movements

insula

cerebral lobe located deep within lateral sulcus; has gustatory cortex (taste)

biggest area of the brain consists of

cerebrum

transverse cerebral fissure separates

cerebrum and cerebellum

cervical dermatomes

cervical nerves involved with information of upper limbs

Plexuses of the spinal cord

cervical, brachial, lumbar, sacral, coccygeal group of nerve fibers that belong to anterior ramus of different spinal nerves, do NOT originate from one single spinal nerve

Anococcygeal nerve

coccygeal plexus; innervates the skin over the coccyx

dural venous sinuses

collect venous blood from the brain and direct it into the internal jugular veins of the neck to drain blood out

inferior cerebellar peduncle

communicates cerebellum with medulla oblongata

middle cerebellar peduncle

communicates cerebellum with pons (helps with coordination of movements)

Descending tracts of the spinal cord

conduct motor (efferent) impulses from the brain to motor neurons in spinal cord until reaching muscles and glands

Myelinated axons have a higher __________ velocity than unmyelinated axons

conduction

Anterior commissure connects

connect two hemispheres commissural fibers

gray commissure of spinal cord

connects masses of gray matter; encloses central canal communicate R & L sides of CNS

anterior white commissure

connects the white matter of the right and left sides of the spinal cord

posterior gray horn

contains somatic and visceral sensory (unipolar) nuclei from dorsal root ganglion

anterior gray horn

contains somatic motor (multipolar) neuron cell bodies that send axons via ventral root until synapse with skeletal muscle

end of spinal cord is called

conus medullaris

bundles of axons that decussate and connect and communicate the 2 cerebral hemispheres

corpus callosum

PNS consists of

cranial nerves, spinal nerves, ganglia, enteric plexuses, sensory receptors

independent of conduction velocity and speed, an action potential signal will never ________ over time and distance. It always stays the same _______ and _______.

decay amplitude size

Tibia is _______ to fibula

deep

Fissures are

deep depressions

Endoneurium

delicate connective tissue that encloses individual axons and their myelin sheaths

meninges of spinal cord

dura mater, arachnoid mater, pia mater also has epidural space and subarachnoid space

epineurium is continuous with

dura mater, it becomes epineurium in spinal nerves

denticulate ligaments

extensions of the pia mater that anchor the spinal cord to the dura mater and limit the movement of the cord. fuse with dura and arachnoid mater to prevent displacement of spinal cord

cerebellar peduncles

fiber tracts that communicate cerebellum with other parts of the brain

filum terminale

fibrous extension of the pia mater; anchors the spinal cord inferiorly to the coccyx

falx cerebelli

fold located b/w two cerebellar hemispheres; separates the two hemispheres of the cerebellum

tantorium cerebelli

fold of dura mater located along Transverse Cerebral Fissure and separates cerebrum and cerebellum

falx cerebri

fold of dura mater located b/w R&L hemispheres of cerebrum along Longitudinal fissure and separates the two cerebral hemispheres attaches to crista galli of ethmoid bone and anchors brain anterior, inferior portion

cerebellum separated by other parts of brain due to presence of

fourth ventricle

The central sulcus separates which lobes?

frontal lobe from parietal lobe

ganglion (plural: ganglia)

group of cell bodies in PNS

Nucleus (plural: nuclei)

group of neuronal cell bodies in CNS

commissural fibers

horizontal fibers that connect gray matter of two hemispheres Anterior commissure and Corpus Callosum

Association fibers

horizontal running fibers that connect different areas of cerebral cortex within same hemisphere Arcuate fibers (look like little arcs) and Longitudinal Fasciculi

Enteric Plexus

in digestive system, plexuses are interconnection of neurons; part of PNS

function of gyri

increase the surface area of the cerebrum

Autonomic Motor neurons

innervate involuntary targets such as smooth muscle, cardiac muscle, and glands

Cranial Reflex

integrating center is the brain stem ex. tracking movements of our eyes when reading

somatosensory association area

integration and interpretation of somatic sensations; allows you to understand texture, size, shape of objects

patellar reflex (knee jerk) tests

integrity of lumbar plexus since nerve responsible for controlling anterior aspect of thigh is femoral nerve (L2, L3, and L4 spinal nerves)

What connects two thalami

interthalamic adhesion

Lateral ventricles communicate with Third ventricle via

interventricular foramen

ventral (anterior) aspect of spinal cord

involved with movement of muscles and motor information

Pyramidal cells in cerebral cortex

large neurons that allow conscious control of precise, skilled, skeletal muscle movements found in primary motor cortex triangle shape

pyramidal cells

large neurons that allow conscious control of precise, skilled, skeletal muscle movements large neurons of primary motor cortex

anterior white column

lies between the anterior gray horns and the anterior median fissure

Third ventricle

located in diencephalon, surrounded by thalamus (interthalamic adhesion) The midline ventricle that conducts cerebrospinal fluid from the lateral ventricles to the fourth ventricle.

lateral gray horn

located primarily in thoracic segment, contains autonomic visceral motor nuclei also extending to ventral root until synapse with cardiac or smooth muscle or glands

dorsal (posterior) aspect of spinal cord

location where sensory nerves get into the spinal cord -coveys sensory information to the brain

Lumbar dermatomes

lumbar nerves involved with info of lower limbs together with sacral nerves

adrenaline (epinephrine) effect in cardiac and respiratory system

make cardiac muscle cells beat faster (excitatory effect) make respiratory system muscles to relax (inhibitory effect)

CSF leaves the ventricular system via the ____________ and enters the subarachnoid space in brain and spinal cord

median aperture and lateral aperture

Brainstem consists of

mesencephalon (midbrain), pons, medulla oblongata

All spinal nerves are ________ nerves

mixed (sensory and motor)

muscle spindles

monitor skeletal muscle length and trigger stretch reflexes

antagonistic muscles

muscle pairs arranged to work against each other to move a joint, needs to be inhibited motor neurons to relax and cause movement

Agonist muscle

muscle that contracts to produce a movement, prime mover

white matter of brain

myelinated axons (inside)

Polarized cell

negative inside, positive outside

Multipolar neurons

neuron with one axon and many dendrites; most common type of neuron Interneurons and Motor neurons

ONLY 2 excitable cells in body are:

neurons and muscle cells

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs have integrative function

Autonomic sensory receptors

not consciously aware of these sensations, come from viscera

Neuronal cell body contains

nucleus

CSF is composed of

nutrients from blood plasma -> water, glucose, and electrolytes

integrating center

one or more regions within the CNS that relay impulses from sensory to motor neurons

Dura mater of brain

outermost layer two layers of dense fibrous connective tissue that seperates in some spaces to form dural sinuses

If blood pressure is high, which system will be activated? What will it do?

parasympathetic nervous system; it will dilate blood vessels

prefrontal cortex

part of frontal lobe responsible for thinking, trouble solving, concentration, behavior, planning, and language; also personality, morality, and judgement

Blood-Brain Barrier (BBB)

physiological barrier between the circulatory system and the central nervous system that establishes a privileged blood supply, restricting the flow of substances into the CNS made up of capillary endothelial cells with tight junctions (only allow lipid soluble compounds thru) surrounded by astrocytes (provide nourishment glucose and oxygen) protects blood from toxins and infections and allowz CO2 and waste to leave brain

Diencephalon: Epithalamus

pineal gland, endocrine gland that secretes the hormone melatonin which regulates wake/sleep cycles

Depolarized cell

positively charged, Na+ enters cell positive inside, negative outside

neuron after the synaptic cleft

postsynaptic neuron

Subdural space of brain

potential space that does NOT normally exist between dura mater and arachnoid mater, has potential to be filled with fluid if necessary (ex. subdural hematoma fills it with coagulated blood)

neuron before the synaptic cleft is called ...

presynaptic neuron

CSF functions

prevents contact of neural tissue with surrounding bone (liq cushion at a constant volume) provides support for brain (reduces weight from 1500 g to 50 g and allows brain to float) transports nutrients to CNS transports metabolic waste away from CNS

what separates two lobes of cerebellum

primary fissure

precentral gyrus also called

primary motor cortex (frontal lobe)

arachnoid granulations (villi)

project through dura mater into superior sagittal sinus, act as one-way valves to control passage of CSF into sinuses due to fluid pressure

CNS Neurons

purkinje cells (found in cerebellum) and pyramidal cells (found on cerebral cortex)

Reflec

rapid, unconscious, involuntary, and fast automatic response to a stimulus

Meningitis means you have a problem with

reabsorption of CSF, since there is no communication b/w where CSF is made and where it is absorbed, thus raising intracranial pressure

spinal anesthesia

regional anesthesia produced by injecting medication into the CSF in the subarachnoid space diffuse faster, not safer

epidural anesthesia

regional anesthesia produced by injecting medication into the epidural space of the lumbar or sacral region of the spine diffuse slower, safer

Somatic Motor Neurons

responsible for reflexes and voluntary control of skeletal muscles

Hydrocephalus

results from overproduction of CSF or obstruction of ventricles or can be related to reabsorption of CSF increased intracranial pressure causes head to become very large in newborns since skull bones are not fused yet in adults, bc rigidity of skull, it keeps pressure within and leads to compression of blood vessels and crushing soft neural tissue and brain damage Treatment: hole in ventricles to drain CSF and using tube to connect it to place in abdominal cavity

longitudinal fissure separates

right and left cerebral hemispheres

S5 and the coccygeal nerve exit via the

sacral hiatus

sacral dermatomes

sacral nerves involved with information of genital area

Neurogenesis in PNS

schwann cells regenerate damaged axons

Somatic Sensory Receptors

sensations that we are aware of and can answer to these voluntarily, come from skeletal muscle and skin

lateral sulcus

separates temporal lobe from all other lobes

parieto-occipital sulcus

separates the parietal lobe from the occipital lobe

anterior (ventral) ramus

serves the muscles and structures of the upper and lower limbs and the skin of the lateral and anterior surfaces of the trunk

Fascicle

several endoneurium wrapped together

posterior median sulcus

shallow longitudinal groove on the dorsal surface of the spinal cord Sulcus = skinny

superior sagittal sinus

sinus b/w R &L cerebral hemispheres superiorly received blood from cerebral veins and CSF drained from subarachnoid space ends here via arachnoid granulations

ONLY muscles in body we can voluntarily move are

skeletal muscles

Protection of the brain

skull (protect brain) meninges (CT layers that are continuation of spinal cord meninges that separate soft tissue of brain from skull) cerebrospinal fluid (cushion and buoyancy) blood-brain barrier (biochemical isolation of brain from main circulation) rich blood supply (blood supply to brain via carotid artery when when blood is deoxygenated and nutrient poor its taken away by jugular vein- helps cool down brain)

Node of Ranvier

small gap between myelinated segments where axonal membrane is exposed; increase speed of impulses

Pia mater of brain

soft, pliable, thin, delicate CT of the meninges that attach to brain on top of cerebral cortex contouring gyrus has blood vessels so helps nourish brain

Cell Body also called

soma or perikaryon

neurons supplying each dermatome

somatic sensory neurons

Coccygeal Plexus

some of S4, S5, and Co1

posterior (dorsal) ramus

spinal nerve branches that serve the deep muscles and skin of the posterior surface of the trunk involved with sensory and motor info of our back

if CSF pressure is greater than venous pressure of superior sagittal sinus, the CSF will

squeeze out of subarachnoid space into bloodstream and get reabsorbed

reflex arc pathway

stimulus -> receptor ->sensory neuron -> relay neuron -> motor neuron -> effector -> response.

Perineurium

surrounds each fascicle of a nerve terminates by blending with CT found surrounding nerve endings and muscle junctions

If blood pressure is low, which system will be activated? What will it do?

sympathetic nervous system; will make blood vessels constrict

Communication between neurons

synapse

2 neurons will never touch, there's always a gap called

synaptic cleft or synaptic gap

largest nuclei in brain

thalamus

Cerebellum

the "little brain" at the rear of the brainstem; 2nd largest part of brain functions include processing sensory input and coordinating complex skeletal muscle movement (dance, drive), responsible for repetitive body movements, coordination, balance and equilibrium

Plasticity

the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience creation of new pathways, involved with learning happens in hippocampus

cerebellar cortex

the cortex that covers the surface of the cerebellum with neuronal cell bodies which is gray matter of cerebellum

Sympathetic Nervous System

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations fight or flight

Parasympathetic Nervous System

the division of the autonomic nervous system that calms the body, conserving its energy rest and digest

neurogenesis

the formation of new neurons from undifferentiated stem cells

each hemisphere controls

the opposite half of the body

Autonomic Nervous System (ANS)

the part of the peripheral nervous system that controls the glands and the smooth muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

Somatic Nervous System (SNS)

the part of the peripheral nervous system that controls voluntary movement of skeletal muscles

primary somatosensory cortex

the region of the anterior parietal lobe whose primary input is from somatic sensory neurons of skin, muscle, and joints

primary motor cortex

the region of the posterior frontal lobe that contains neurons that control movements of skeletal muscles

Fourth ventricle

the ventricle located between the cerebellum and the dorsal pons, in the center of the metencephalon b/w pons and cerebellum

dura mater

thick, durable, and toughest outermost layer of the meninges surrounding and protecting the brain and spinal cord

what is between right and left thalamus

third ventricle - thalami surrounds it

thoracic dermatomes

thoracic nerves involved with information of thorax and abdominal area

Somatic Sensory Neurons

transmit information about the outside world and our position within it to the CNS; aware of these sensations; associated with Somatic Sensory receptors

Autonomic Sensory Neurons

transmit sensory input from autonomic sensory receptors in visceral organs & blood vessels to CNS; not aware, automatic; associated with Autonomic Sensory receptors

meningeal layer of dura mater of brain

true layer that covers brain and extends into vertebral canal od spinal dura mater

Purkinje cells

type of interneuron that carries information from the cerebellum to the rest of the brain and spinal cord found in cerebellum

visual association area

uses past visual experiences to interpret visual stimuli; interpret and connect visual stimuli

Spinal cord and meninges go through hole in the middle of vertebra called

vertebral foramen

arachnoid trabeculae

web like threads extending from arachnoid to pia mater made of collagen fibers which helps anchor blood vessels to place

Arachnoid mater

weblike middle layer of the three meninges

arbor vitae of cerebellum

white matter of the cerebellum

projection fibers

white matter; connect the hemispheres with lower brain or spinal cord

anterior median fissure

wide, deep crease along the ventral surface of the spinal cord fissure=fat

CN VI Abducens Nerve

•Function: Motor function •Controls 1 (of the 6) extra-ocular eye muscles •Lateral rectus muscle: abduct eyes (moves eye laterally)

CN XII Hypoglossal Nerve

•Function: Motor function; Controls tongue movement innervates motor information to tongue, what keeps food in the middle of oral cavity when eating; leaves cranium and passes through the hypoglossal canal of occipital bone