final exam

innervation of the ulnar nerve

innervate flexor muscles in forearm (not innervated by median nerve), most intrinsic han muscles and skin of the of 5th digit and medial side of 4th digit

innervation of musculocutaneous nerve

innervates anterior arm muscles, including biceps brachii and brachailis and skin covering lateral arm

innervation of the median nerve

innervates palmaris longus and wrist and digital flexors, some intrinsic muscles of hand and skin over anterior thumb, 2nd, 3rd digits, and lateral half of 4th digit

Csf flow path: right and left lateral ventricles

(first and second ventricle); within their respective cerebral hemispheres

to point discrimination threshold

,ethod for measuring relative size of receptive field

simple stretch reflex

- bodies reflecive response to stretching of muscle to shorten it back to within its "set" optimal length - patellar knee jer reflec and jaw jerk reflex are exmaples of simple stretch reflexes prevents damage to your teeth calcaneal reflex

sensory neurons detect stimuli at sensory receptors after which the following events occur

- detected stimuli are transmitted along snesory neuron (spinal or cranial) to cerebral cortex - sensory information is interpreted, integrated, and an appropriate motor response is selected and initiated

the motor response is initiated by commands from the motor areas of the cerebral cortex which leads to the following events

- impulses travel to spinal cord where neurons synapse with lower motor neurons of pns - lower motors neurons carry impulses to appropriate muscles via cranial or spinal nerves where the trigger contractions

what is the function of a nerve plexus

-organizes the nerves - intermingling of nerves from multiple spinal cord levels minimize loss of motor control and sensation in an area following spinal cord injury

pair of coccygeal nereves

1

a possible mathway for information transferred by the conduction of an action potential from one region of the brain to antoher

1. an action potential orginates in of the gray matter regions of the brain 2. the action potetnial travels to another area of gray matter by projection fibers 3. a new action potential is generated and sent to neighboring gray matter by association fibers 4. another action potential is generated and sent to the other cerebral hemisphere by commisural fibers

the basic mechanisms of transduction

1. before any stimulis arrives, the ion channels in the axolemma of the osmatic sensory neurons are closed 2. whena stimulus such as pressure is applied, mechanically gated Na+ channels open and Na+ enter the axoplasm, generating a receptor potential 3. if enough Na_ enter that the membrane potential reaches threshold, voltage gated Na+ channels open. This triggers an action potential, which will be propagated along the axon to the spinal cord psuedounipolar neurons

big picture of cns control of voluntary movement

1. motor assocation areas select a motor program 2. motor association areas and the substantia nigra stimulate the caudate nucleus and putamen 3. the caudate nucleus and the putamen inhibit the globus pallidus. The globus pallidus sttops inhibiting the thalamus 4. motor nuceli of the thalamus stimulate upper motor neurons 5. upper motor neurons execute the motor program by sending signal to the lower motor neurons in the spinal cord and pns 6. the cerbellum monitors movement and conect to motor error

from pns to cnsL sensory reception and sensory receptors

1. stimuli are first detected by sensory neurons along the ascending tract 2. stimulus is transmitted by sensory neurons to cns 3. stimulus is integrated and interested by cns neurons in the parietal, occipital, and temporal lobe

multiple sensory stimuli from different regions of body

1. stimulus is detected by neurons in the pns and sent as sensory input to the cns 2. in the cns, sensory input is sent to cerebral cortex to be interpreted 3. when cns has received all sensory inputs are integrated in cns into single perception ( a conscious awareness of sensation)

the three types of neurons that are directly involved in eliciting a muscle contraction

1. upper motor neurons with cell bodies in motor area of cerebral cortex (most) or brainstem (some)- axons descend through cerebral white matter to decussate in brainstem though spinal cord; synpase with loval interneuron (cerebral medulla) 2. local interneurons pass message from upper motor neurosn to neighboring lower motor neurons 3. lower motor neuron cell bodies reside in anterior horn of spinal gray matter, axons (components of pns) exit cns to innervate skeletal mucle

pairs of thoracic nerves

12

parasympathetic nervous system cranial nerves

3, 7, 9, 10 innverate most thorcacic and abdominal viscera branches of the vagus nerves contribute to the cardiac, pulmonary, and esophageal plexus

pairs of spinal nerves

31

pairs of lumbar

5

sacral nerves

5

pairs of cervical

8

composition and function of csf

Cerebrospinal fluid (CSF) - clear, colorless liquid similar in composition to blood plasma; protects brain in following ways: 2. Cushions brain and maintains a constant temperature within cranial cavity 3. Removes wastes and increases buoyancy of brain; keeps brain from collapsing under its own weight Choroid plexuses - CSF is manufactured here; found in all four ventricles where blood vessels come into direct contact with ependymal cells that produce CSF; composed of Fenestrated capillaries have gaps between endothelial cells; allow fluids and electrolytes to exit from blood plasma to enter extracellular fluid (ECF)

parasympathetic effect on cardiac muscle cells

Cn X decrease heart rate and blood pressure with CN X

long term potentiation and consolidation

Consolidation- process of converting immediate or working memory into long term memory; involved increase in synapses Formation and storage of declarative memory: echo Long term potentiation- mechanism by which hippocampal neurons encode long- term declarative memories involved an increase in synaptic activity with increase in neurotransmitters (glutamate) or receptors between associated neurons Retrieval of memories seems to be mediated by pathways involving hippocampus and prefrontal cortex Formation and storage of nondeclarative memory doesn't rely on hippocampus

anesthesia

Epidural anesthesia- local anesthetic medication is injected into epidural space through and inserted needle Causing numbing (inability to transmit motor or sensory impulses) of nerves extending off spinal cord below level of injection Commonly given during childbirth and other surgical procedures Spinal epidural goes in the subarachnoid space Lumbar puncture( spinal tap) needle inserted into subarachnoid space between fourth and fifth lumbar vertebrae; avoids possibility of injuring spinal cord

slowly adapting receptors

response to stimuli with constant action potentials that don't diminish over time

meninges diseases

Infection meningitis- potentialyl life threatening infection of meninges in subarachnoid speace, inflammation occurs, causing classic signs: headache, lethargy, stiff neck, fever Diagnoisus- examination of csf for infectious agents and whte blood cells (cells of the immune system); bacteria and viruses are most common causative agents Viral- generally mild; resolves in 1-2 weeks Bacterial- can rapidly progress to brain involvement and death; aggressive antibiotic treatment necessary; some most common forms are preventable with vaccines

abducens

somatic motor; lateral rectus muscle

reticular formation

Midbrain, pons, and medulla oblongata Receieves information from limbic system, cerebral cortex area Send it to reticular formation (over 100 nuclei) center where a response will happen Collection of over 100 nuclei found all three brainstem subdivisions making this one of the most complex regions of brain Input Is received from multiple sources including: cerebral cortex, limbic system, and sensory stimuli Output is sent throughout entire brain and spinal cord Function in sleep, pain transmission and mood Serve motor

effects of norepinephrine on cardiac muscle cells when it binds to beta 1 receptors

NE binds to beta 1 receptors oepns ion channels open on cardiac muscle cells; raises both rate and force of contraction; amount of blood delivered to tissues and blood pressure both increase; maintains homeostasis during increase physical activity

post central gyrus

somatic sensory cortex

reflexes: visceral and somatic

type of organ in which refles takes place

emotion

Visceral motor responses- blushing or heart racing; mediated by hypothalamus Somatic motor responses- smiling, laughing, frowning, and crying; mediated by hypothalamus and limbic cortex through reticular formation With age: sensory functions decline because the number of photoreceptors decline, balance

reflex

a reflex arc produces involuntary response to a stimulus programmed, autonomic response to stimuli in a three step sequence

cognitive functions

include processing and responding to a complex external stimuli, recognizing related stimuli, processing internal stimuli and planning appropriate responses to stimuli

language

ability to comprehend and produce words

cholinergic receptors bind to

acetylcholine

balance between parasympathetic and sympathetic nervous systems

actions of parasympathetic division directly anatgonize those of sympathetic division; maintain a delivate balance to ensure that homeostasis is preserved

phasic receptors undergo

adaption

beta 3 receptors

adipose cells and smooth muscle cells in walls of digestive tract

effects on cells of the adrenal medulla

adrenal= epinephrine noradrenalin= norepinephrine

classes of sympathetic receptors

adrengergic receptors- bind to epinephrine and noreipinephrine; two major types of adrenegic receptors, alpha and beta are classified into subtypes: alpha 1: smooth muscle cell membrane of blood vessels in skin, GI tract and kidneys, arrector pili muscles in dermis alpha 2 receptors: on plasma membranes of preganglionic sympatetic neurons instead of in peripheral target cells; differ from other adrengergic receptor subtypes; usually, action potential in a preganglionic neuron leads to ACh release: stimulates postganglionic neuron; when norepinephrine binds to alpha 2 receptors, axon terminal is hyperplarized; slows or cancels action potential; component of negative feedback lops where preganglionic neuron activity at axon terminal and norepinephrine blocks voltage gated calcium channels beta 1 receptors: plasma membranes of cardiac muscle cells, certain kidney cells nad adipose cells beta 2 receptors: plasma membrane of smooth muscle cells of airways of respiratory tract (bronchioles), wall of urinary bladder, blood vessels of skeletal and cardiac muscle, and cells found in liver, pancreas, and salivary glands

cranial meninges: dura mater- meningeal dura

inner layer; avascular and lies superficial to arachnoid mater

hiccups

annoying spasms of diaphragm that cause a forceful inhalation of air - one way to end many cases of hiccups involved in the phrenic nerve and you must apply form pressure to muscles of neck that innervate the phrenic nerve until hiccups stop in 5- 10 seconds

visceral reflex arc

ans manages vital involuntary process sensory stimulus leads to a predictable motor response 1. sensory signals... from the viscera and skin are sent by afferent sensory neurons to the brain or spinal cord integration... the stimuli are integrated by the cns motor impulses... from the cns are snet via efferent sensory neuron in cranial and spinal nerves to autonomic ganglia autonomic ganglia... send the impulses via other efferent neurons to various target organs, where they trigger a motor response in the target cells

spinal gray matter: horns

anterior (ventral) horn gives ruse to anterior motor nerve roots; neuron cell bosies found in this region are involved in somatic motor functions (skeletal muscle contraction) posterior (dorsal) horn gives rise to posterior sensory nerve roots; neuron cell bodies found in this region are involved in processing incoming somatic and visceral sensory information lateral horn found only in spinal cord between first thoracic vertebra and lumbar region; contains cell bodies of autonomic motor neurons involved in control of viscera via ans

facial sensory innervation

anterior 3/3 of the tongue; taste

brachial plexus

anterior rami c5-t1 branches of this plexus serve cutaneous branches innervates skin of shoulder and upper extremity, motor branches innervate shoulder and upper extremity muscles

lumbar plexus

anterior rami of L1- L5; branches innervate pelvis structures and lower extremity femoral nerve anterior thigh muscles (quadriveps) and skin over anterior and medial thigh and leg orbturator nerve gracilias muscle genitofermoral skin of scrotuum and labia majora

cervical plexus

anterior rami of c1-c5 branches of the plexus serve plrenic nerve which innervates diaphragm and has c3-c5 ventral rami

sacral plexuses

anterior rami of spinal nerves L4-S4 branches from this plexus innervate pelvis, gluteal region, and much of lower extremity

cranial meninges

are composed of dense irregular collagenous tissue

receptive fields

areas served by a particular neuron; neuron with more branches innervate larger receptive fields

cranial nerves

attach to brain and mostly innervate structures in head and neck; not formed by fusion of sensory and motor roots (like spinal nerves); allow for purely sensory, mixed, and mostly motor nerves

motor pathways from the brain through the spinal cord

axons from the cortical motor areas unite to form several white matter tracts. The largest of these tracts are the right and left corticospinal tracts and the corticonuclear tracts 9for cranial nerves)

vagus innervation

base of of tongue; taste

facial- sensory

bell's palsy

cranial meninges: epidural space

between cranial bones and dura mater, potential space as dura is tightly bound to bone

csf flow path: fourth ventricle

between pons and cerebellum; connected to third ventricle by cerebral aqueduct

large receptive field

body regions with fewer neurons that are not involved in sensoring envirnment (skin of forearm)

small receptove field

body regions with many neurons whose primary function is sensing environment (fingertips, tongue, pharynx)

parasympathetic neurotransmitters and receptors

both pre and postganglionic paasympathetic neurons release. Acetlycholine at their synapses, and the effect is generally excitatory cholinergic receptors 1. nicotonic located in membranes of all postganglionic neurons 2. muscarinic located in membranes of all parasympathetic target cells

what does the central nervous system included

brain spinal cord

chemoreceptors

can be either interoreceptors or exteroreceptors; depolarize in response to binding to specific chemicals to receptors; generate a receptor potential as sodium ion channel open

communicating ramus

carries autonomic fibers of the sympathetic nervous system

four divisions of the brain

cerebrum, diencephalon, cerebellum, and brainstem

trigeminal neuraglia

chronic pain syndrome; involved one or more branches of trigeminal nerve patients suffer brief attacks of intense pain that last from a few seconds to two minutes

gray matter in basal nuceli

clustests of neuron cell bosies involved in movement composed of: globus pallidus and stratum caudate

innervation of common fibular nerve

common peroneal skin of anterior and distal leg suplies ankle dorsiflexors (tibialis anterior) and muscles on dorsum of foot

diencephalon: mamillary bodies

connect hypothalalmus with limbic system; involved in olfactory reflexees and emtional response to odors; memory

endoneurium

connective tissue layer covering each individual axon within a fascicle

perineurium

connective tissue layer of small groups of bundled axons called fascicles

cerebellum: cerebellar penduncles

connects cerbellum to brain stem (at ponds), white matter tracts

sensory functions

detection of sensations within and outside body; also is a function of pns

spinal nerves anterior root

consists of motor neurons from anterior horn

spinal nerves posterior root

consists of sensory neurons from posterior horm

parasympathetic effect on smooth muscle cells

constriction of the pupil- CN III; reduces amount of light allowed into eye accommodation of the lends for near vision: Cn III and contraction of ciliary muscle; changes lens to a more rounded shaped constriction of the bronchioles CN X; reduces air flow through bronchioles contraction of the smooth muscle lining the digestive tract Cn X; produces rhythmic contractions called peristalsis propels found through digestive tract relaxation of digestive and urinary sphincters CN X and sacral nerves; promoters urination and defecation engorgement of the penis or clitoris

peripheral nerves motor nerves

contain mostly motor neurons (also some sensory neurons involved in muscle stretch and tension)

peripheral nerves sensory nerves

contain only sensory neurons

medulla oblongata: pyramids

contain upper motor neuron fibers of cortocospinal tract (also called pyramidal tract)

peripheral nerves mixed nerves

contains both sensory and motor neurons

what are the three protective features of the brain

cranial meninges, cerebrospiinal fluid, and blood brain barrier

touch stimuli: nondiscriminative touch

crude touch lacks fine spatial resolution

fissures

deep grooves found on surface of cerebrum

insulas

deep underneath lateral fissures; involved in functions related to taste and viscera (internal organs)

cranial meninges: pia mater

deepest meningeal layer; only meninx in physical contact with brain tissue

sleep

defined as reversible and normal suspension of consciousness physiologically, sleep appears to serve an energy restoration function; allows brain to replenish it glycogen supply sleep is required for survival

pharmacology and sympathetic nervous system receptors

different subtypes of sympathetic nervous system receptors have provided targets for medication therapy for many different disease states including 1. alpha 1 blockers 2. alpha 2 blockers 3. beta blockers 4. beta 2 agonists

thoracic spinal nerve

do not for plexuses, except T1 posterior ramus innervates deep back muscles anterior ramus travels between two ribs as an intercostal nerve

protection of spinal cord: 3 spinal meninges

dura mater, subarachnoid mater, and pia mater

cellular metabolism: higher energy demand norepinephrine has the following three effects

during times of sympathetic activation, nearly all cells, especially skeletal muscle, require higher amount of atp, to meet his higher energy deman norepinpehrine 1. beta 3 receptors adipocytes; breakdown of lipids; release free fatty acids into bloodstream 2. beta 2 receptors liver cells; release of glucose from gylcogen and synthesis of glucose from other resources 3. ne binds beta 2 receptors on cells of pancreas; release of hormone glucagon; increase blood glucose levels

gyri

elevated ridges found between sulci; increase surface area of brain; maximizing limtied space within confines of skull

mechanoreceptors

encapsulated interoreceptors or exteroreceptors found in musculoskeletal system and skin; depolarize when mechanically deforms tissue; mechanically gated ion channels for vibration, light touch, stretch, and pressure

diencephalon: epithalamus

endocrine gland called pineal gland; secretes melatonin; horomone involved in sleep/ wake cycle

motor program

even simple movement require stimulation from countless neurons as part of a selected group of actopms - premotor cortex association areas - upper motor neurons in sprimary motor cortex - basal nuclei, cerbellu, and prefrontal cortex - descending tracts - interneurons in anterior horn of spinal cord - lower motor neurons in pns to skeletal muscle

integrative functions

exclusive function of cns - interpretation of sensory information - planning and monitoring movement - maintenance of homeostasis - higher mental functions such as language and learning - decision making processes

thermoreceptors

exteroreceptors, most of which are slowly adapting; depolarize in response to temperature changes; separate receptors detect hot and cold

facial- somatic motor

facial expression

tactile corpuscle

fast adaption, discrimination touch with less spatial resolution

anterolateral system

fibers transmit pain, temperature, and nondiscrimative touch first oder neuron synpase on second order neurons in posterior horn; then decussate second order neurons pass through the spinothalamuc tracts of spinal cord and brainstem to thalamus third order neurons in thalamus then transmit impulses of primary somatosensory cerebral cortex where is is processed, perceived, and passed along to cortical association areas

central canal: gray commissure

filled with csf; seen in center of spinal cord; surrounded by two think strips of gray matter (gray commissure) that connects horn

touch stimuli: tactile sense

fine or discriminative touch include vibration, two point discrimination and light touch

the basic pathway of sensory pathways through the spinal cord to the brain

first order neuron synapse in the dorsal horn ( spinal cord) then travels up whatever column depending on the pathway second order neuron synpases in either brain stem or thalamus third order neuron synpases in the primary somatosensory cortex (post central gyrus)

medulla oblongata: decussate

fivers decussate (crossover) within pyramids; motor fibers originating from right side or cerebral cortex descend through left side of spinal cord and vice versa

pathway for the formation, circulation, and reabsorption of csf

fluid and electrolytes leak out of the capillaries of the choroid plexus ependymal cells secrete csf into the ventricles- lateral comes first csf circulates through and around the brain and spinal cord in the subarachnoid space some csf is reabsorbed into blood in the dural sinuses through the arachnoid granulation or villi or villius csf passes after the fourth ventricle and goes through these three structures: central canal, later and median aperture

cerebellum: folia

folia gray matter cover exterior cerebellar surface to increase surface area of region

csf flow path: third ventricle

found between diencephalon; connected to lateral ventricles by interventricular foramen

cranial meninges: subarachnoid space

found deep to arachnoid mater adn superficial to pia mater; contains major blood vessels of brain, filled with csf

spinal cord: ascending tracts- spinocerebellar tracts

found in lateral funiculi; carry information about joint position and muscle stretch from entire body to cerebellum

spinal cord: ascending tracts- posterior columns

found in posterior funiculi; carry someatosensory information, such as propioception and touch

CSF flow through structures

four ventricles within brain are linked cavities that are continueous with central canal of spinal cord lined with ependymal cells filled with cerebrospinal fluid

cerebellum- function

functionally connected ithi cerebral cortex, basal nuclei, brainstem, and spinal cord, and together coordinate movement

diencephalon: subthalamus

functionally connected with basal nuceli to control movement

gray matter: cerebral cortex

functionally most complex part of the cortex; most of cerebral cortex neocortex (most recently evolved region of brain); has a huge surface area; all neurons in cortex are interneurons primary motor cortex- plans and executive movement primary sensory cortices- first regions to receive and process sensory input association areas integrate different types of information: - unimodal areas integrate one specific type of information -multimodal areas integrate information from multiple different sources and carry out many higher mental functions

swalloing is a somatic motor function

glossopharyngeal and vagus

oculomotor- somatic motor

goes to extrinsic eye muscles superior medial, inferior rectus, inferior oblique

hypothalamus- homestasis

homeostasis is controlled centrally by hypothalamus and brainstem reticular formation; actions carried out by the two divisions of ans

nervous system and endocrine system are main system dedicated to maintain what

homestasis

spinal nerves posterior root ganglion ( or dorsal root ganglion)

houses cell bodies of sensory neuron which are called^^

classification of sensory neurons- speed of action potential factors

if warm- conduct faster large diameter axons with thick myelin sheaths- conduct propriceptive (joint potion, tendon position) information and discriminative and fastest small diameter axons with little myelin- carry pain and temperature stimuli slowest

adrenal medulla cuts on top of each kidney

in direct contact with preganglionic sympathetic neurons; medulla is composed of modified sympathetic postganglionic neurons with the following functions: - ACh is released from preganglionic neurons that then bind to chloinergic nicotinic receptors on the adrenal medulla cells -ACh stimulates the medullary cells to release norepinephrine adn epinephrine into the bloodstream. IN this case these are considered horomones rather than neurotransmitters - horomones act as long distance chemical messangers; interface (bind) between endocrine and sympathetic nervous systems

innervation of the radial nerve

innervates triceps brachii and brachioradialis muscles and most of extensor muscles of forearm; innervates skin over posterior thumb, 2nd digit, 3rd digit, and lateral half of 4th digit

facial (sublingual and submandibular) and glossypharngeal (patriated)

innverate salivary gland

salivary reflex

inolvuntary, parasympathtic and increases saliva from facial and glossopharyngeal

temporal lobe

involved in hearing, language, memory, and emotions

brainstem: superior and inferior colliculi

involved in visual and auditory functions respectively; project to thalamus

flexion or withdrawl reflec

involved rapidly conducting nociceptors; polysynpatic; withdraw limb from painful stimuli quads

referred pain

is a phenomenon whereby pain that originates in an organ is perceived as cutaneous pain occurs because many spinal nerves carry both somatic and visceral neurons, so visceral sensations travel along same pathways as so somatic sensations generally located along dermatome for a particular nerve

cognition

is composed of asocation areas in the cerebral cortex that perform a diverse group of tasks collectively. are responsible for social and moral behavior, intelligenes, thoughts, problem solving skills, language, and personality

homeostasis

is defined as the maintenance of a relatively stable internal environment in the face of ever-changing conditions. Homeostatic functions include maintaining fluid, electrolyte, and acid-base balance; blood pressure; blood glucose and oxygen concentrations; biological rhythms; and body temperature. Thirst and hunger centers

facial- parasympathetic

lacrimal gland

innervation of tibial nerve

largest branch of sciatic nerve innervate hamstring muscles and gastrocnemius. soleus skin of leg as well as skin and muscles of foot

purkinie cells

largest neurons in the cns (1000000-200000 synapses) inhibitory

spinal cord: descending tract- corticospinal

largest of descending tracts; help control skeletal muscle below head and neck originate from motor areas of vertebral cortex; descend then decussate within brainstem travel through lateral funiculi of spinal cord; fibers deliver motor information to appropriate location in anterior horn

gray matter: cerebral cortex motor cortices and upper motor neurons

located in the frontal lobe primary motor cortex: involved in conscious planning of movement; located in precentral gyrus of frontal lobe upper motor neurons: of each cererbal hemisphere control motor activity of opposite side of body; interneurons that connect to pns neurons called low motor neurons; execute order to move premotor cortex: located anterior to primary motor cortex; unimodal motor association areas are areas involved in planning, guidance, coordination, and execution of movement frontal eye fields: paired motor association areas; one on each side of brain anterior to premotor cortex; involved in back and forth eye movements as in reading

gray matter: cerebral cortex, sensory cortices

located in the rest of the lobes have unimodal association areas primary somatosensory area- in post central gyrus of parietal love; intiatally perceive somatosensory assocation cortex- parietal lobe; details of sense perceived primary visual cortex- occipital love; first area to receive visual input visual association area which processes color, object movement, and depth primary auditory cortex- temporal lobe; first to receive auditory information auditory assocation cortex- association area for furthering processing sounds gustatory cortex- taste information processing; scatted throughout both insula and parietal lobes verstibular areas- deal with equilibrium and positional sensations; located in parietal and temporal lobes olfactory cortex- processes sense of smell; in evolutionarily older regions of brain; consists of several areas in limbic and medial temporal lobes language areas: brocas area- in frontal lobe; premotor areas responsible for ability to produce speech sounds wernicke's area (integrative speech area)- in temporal and parietal lobes; responsible for ability to understand language prefrontal cortex- occupies most of frontal lobe; communicates with diencephalon, other regions of cerebral gray matter, and association areas located in other lobes; many functions including modulating behavior, personality, learning, memory, and an individual personality state parietal and temporal association areas- occupy most of their respective loves; perform multiple function including integration of sensory information, language, maintaining attention, recognition, and spatial awareness

innervation of sciatic nerve

longest and largest neve in the body innervates skin of hip joint in posterior thigh before it divides into tibial and common fibular nerves

brainstem

maintains homeostasis, controls ertain reflexes, monitors movement, integrates and relays information

peripheral nerves innervate

majority of structures (organs) in body

roles of cerebral cortex in voluntary movement

majority of upper motor neurons that control complex movements reside in primary motor cortex and premotor and motor association areas plans and initiate voluntary movement by selecting an appropriate motor program and coordination upper motor neurons in primary motor cortex

parasympathetic sacral nerves

make up the pelvic nerve component of this division. This subdivision supplies the last segment of the large intestine, the urinary bladder, and the reproductive organs pelvic splanchnic nerves terminal ganglia

cns development

nervous tissue is derived from ectoderm which forms the neural tubes and the 4th week of development

stretch receptors: muscle spindles or extrafusal muscle fibers

mechanoreceptors in muscles and tendon monitor muscle length and force of contraction muscle spindles- composed of regular contractile muscle fibers with actin and myosin (extrafusal muscle fibers) and specialized muscle fibers (intrafusal muscle fibers) with absent contractile proteins in central area two classes of sensory neurons innervate intrafusal fibers primary afferent respond first to stretch secondary afferent respond to both static length and muscle and position of a limb

golgi tendon organs

mechanoreceptors located within tendons near muscle tendon junction monitor tension generated by a muscle contraction consists of bundles of collagen fibers attached to about 21 extrafusal muscle fibers only one somatic sensory axon that fires more rapidly as greater tension is generated with each contraction; information is sent to cns

nicotinic receptors

membranes of all postganglioninc neurons within sympathetic ganglia and adrenal medullae

6 classes of mechnoreceptors

merkel cells- found in epidermal rides of fingertips; slow adapting receptors detect discriminative touch stimuli (object form and texture) tactile corpuscles (meissner corpuscles)- in dermal papillae; rapidly adapting tactile exteroreceptors; transmit discriminative touch stimuli ruffini endings (bulbous curpuscles)- spindle shaped receptors found in dermis, hypodermis, and ligament; slowly adapting receptors respond to continous stretch and movement lamellated corpuscles (pacinian corpuscles)- rapidly adapting receptors found deep within dermis; detect high frequency vibratory and deep pressure stimuli hair follicle receptors- free nerve endings surrounding base of hair follicles found in this skin; respond to stimuli that cause hair to bend proprioreceptors- in musculoskeletal system; detect movement and position of a joint or body part

brainstem: pons

middle portion ascending sensory and descending motor tracts connect to cerebellum by cerebellar penducle breathing rem sleep and arousal

drugs blocking either receptors

mnay drugs block either ACh release or ACh receptors urinary retention- block relaxing effect on urinary sphincters, and makes passing urine more difficult constipation- block effect on smooth muscle of digestive tract; causes digested food to move more slowly through tract and can lead to constipation dry mouth- caused by a decrease in secretion of saliva

cerebellum

monitors and coordinates movement

medulla oblongata

most inferior, continuous with spinal cord at foramen magnum; Ans functions of breathing, heart rate and blood pressure (RAS)

sympathetic chain ganglia

most of postganglionic cell bodies founf here, "chainlike" appearnace; both sides of veretbral column; run parallel preganglionic neurons from materal horns of thoracic and lumbar spinal cord; exit via anterior root; preganglionic acons separate from anterior ramus of spinal nerve to form a small nerve called white (myelinated) rami communicans; leads to postganglionic cell bodies in sympathetic chain ganglion collateral ganglia synpases between preganglionic axon terminal with postganglionic neurons cell body; preganglionic axons pass through chain ganglia without forming synpases; located near target organ splanchic nerves- preganglionic axons that synpase with collateral ganglia near organs of abdominopelvic cavity gray (unmyelinated) rami communicans; unmyelinated postganglionic axons that exit chain ganglia and reunite with spinal nerves

brainstem: midbrain, mesenchephalon

most superior surrounds cerebral aqueduct (connects third and fourth ventricles)

somatic motor division ans

motor neuron, innervate skeletal muscle

autonomic motor division ans

motor neurons innervate smooth and cardiac muscles and glands

hypoglossal

motor to the tongue

what are the 3 categories of cns functions

motor, sensory, integrative

what is the cns involved in

movement interpreting sensory information maintaining homeostasis functions relating to the mind

role of lower motor neurons

multipolar neurons: cell bodies located- whose cell bodies are in either anterior horn of spinal cord or brainstem axons are in pns motor neuron pool- gorups of lower motor neurons from anteriior horn of spinal cord that innevate same muscle alpha motor- majority of neurons within pools; stimulate skeletal muscle fibers to contract by excitation contraction mechanism innervate extrafusal neurons gamma motor: innervate intrafusal fibers; part of specialized stretch receptors (muscle spindle or tendons)

cerebral white matter

myelinate fibers: commisural fibers: connect reight and left hemispheres; largest one is corpus callosum projection fibers: connect serebral hemispheres with other parts of brain and spinal cord association fibers: restricted to a single hemisphere; connect gray matter or cortical gyri with one another

the anterior rami of the cervical, lumbar, and sacral spinal nerves each merge to form complicated networks of nerves called

nerves plexuses

diencephalon: hypothalamus

neuron perform several vital fujnctions critical to survival; inclue regulation of autonomic nercous stem, sleep/ wake cycle, thrist and hunger, and body temperature endocrine- seceretes releasing and inhibiting horomones that affect pituitary gland horomone secretion; ADH and oxytocin neurohoromones come from here emotions especially rage and fear sexual behavior

brainstem: substantia nigra

neurons that secrete dopamine work with basal nuclei to control movement

sympathetic neurotransmitter- acetylcholine

neurotransmitter used in excitatory synapses betwen sympathetic preganglionic axons and postganglionic neurons; transmit action potentials to target cell

reflexes- monosynaptic and polysynpatic

number of synapses that occur between neurons involved in arc

crossed extension reflex

occurs simultaneously on opposite side of body for balance and postural support while other limb is withdrawn from a painful stimulus

motor cranial nerves

oculomotor, trochlear, abduscens, accessory, hypoglossal

sensory cranial nerves

olfactory, optic, vertibularcochlear

muscarinic receptors

on sweat glands in skin

pupillary and concentual

optic and oculomotor (parasympathetic)

spinal white matter: ascending and descending tracts

organized into general regions called funiculi or columns; three (posterior funiculus, lateral funciculus, and anterior funiculus) lie on each side of spinal cord white matter or organized into tracts sensory pathways travel in posterior and lateral funiculi while motor pathways travel in anterior and lateral funiculi

spinal nerves

originate from spinal cord and innervate structures below head and neck; posterior and anterior root fuse to form spinal nerve just lateral to posterior root ganglion, 31 pairs of spinal nerves are mixed nerves

cranial meninges: dura mater- periosteal dura

outer layer, bones and cranium; functions as periosteum with extensice blood supply in epidural space

epineurium

outermost layer of connective tissue that holds motor and sensory axons together (entire nerve)

cranial meninges: dura mater

outermost meninx; thicket and most durable of three layers, double layered membrane

processing of pain stumli

perception of pain stimuli is called nocoception sensory discrimination- localization, intensity, and quality is perceived and analyzed in the somatosensory association cortex sent to basal nuclei, limbic system, hypothalamus, and prefrontal cortex, where meotional and behavioral aspect of pain are processed cerebral cortex appears to have a significant influence on perception and modulation of pain evident by a phenomenon called the placebo effect endorphins decrease sensitivity to pain stimuli or posterior horn neurons

cerebrum

performs higher mental functions, interprets sensory stimuli, and plans and initiates

sensory and motor neuron disorders

peripheral neuropathies- disorders that impact sensory and motor neurons of pns sensory neuron disorders: lover motor neuron disorders: result from injury of spinal or cranial nerve of lower motor neuron cell body

tactile senses

pertain to fine or discrimation touch, and include vibration, two point discriminationa nd light touch while nondiscriminative touch or crude touch lacks the fine spatial resolution of tactile senses

general somatic senses

pertain to touch, stretch, joint position, pain, and temperature. Most senses are considered mechanical senses as they have mechanoreceptors

frontal lobe

planning and executing movement and complex mental function such as behavior conscience and personality

somatosensory association cortex

plays a major role in processing sensory input and sending it to: limbic system involved in tactile learning and memory, also sends sensory input to parietal and temporal association areas white integrate and relay information to motor areas of frontal lobe

five/three steps of reflex arc

pns detects and delivers stimulus to cns sensory afferent division cns integrates stimulus motor efferent division pns deliver motor response from cns to effectors

detecting and interpretation for somatic sensation

pns: stimulus- sensory receptors and generate receptor potential and if the summate pns: action potential- down sensory neuron first peripheral then central pns to cns- ascending tract cns action potential- to sensory lobe (parietal, temporal, and occipital) travel first order neuron the ascending tract of second order neuron then the one to the lobes is the third order tract

golgi tendon reflex

polysnaptic reflexes; protect muscles and tendon from damaging forces cause muscle relaxation; opposite of simple stretch reflex action when tension is muscle and tendon increase dramatically, golgi tendon organs signal spinal cord and cerebellum motor neurons innervating muscle are inhibited while antagonists muscles are simultaneously activated

glossophyrangeal innervation

posterior 2/3 of the tongue; taste

sympathetic neurotransmitter- norepinephrine (nonadrenalin)

postganglionic axons release 1 to 3 neurotransmitter ach, epinephrine (adrenalin), or norepinephrine (noradrenalin; most frequently utilized neurotransmitter released from synapses between postganglionic acons and target cells)

effects on secretion from sweat glands

postganglionic sympathetic neurons secrete ACh which binds to cholingic and muscranic receptors smypathetic nervous system attempts to maintain body temperature homeostasis during periods of increased physical activity. Negative feedback post ganglionic sympathetic neurons release ACh onto sweat glands cells which binds to muscarininic receptors that increase sweat gland secretion

parasympathetic nervous system

preganglionic are long while postganglionic are short craniosacral dicion- preganglionic cell bodies are located within the nuclei of several cranial nerves (3, 7, 9, 10) and sacral (s2-s4) region\ cell bodies of postganglionic neurons are usually located near the target organ in brainstem and sacral region rest and digest division

sympathetic nervous system

preganglionic axons are: short postgangliunic axons are: long thoracolumbar division (t1-l2); preganglionic cell bodies originate sympathetic ganglia located near spinal cord, where preganglionic axons synpase with postganglionic neuron cell bodies fight or flight division

3 synapse options between pre and post ganglionic synpathetic neuron

preganglionic axons can synapse with a postganglionic neuron int he sympathetic chain ganglion preganglionic axons can ascend or descend and synapse in the post ganglionic neuron in a different chain ganglion preganglionic axons can pass through the chain ganglia.. sympathtic chain ganglia and synapse with a postganglionic in collateral ganglia

two neurons in ans

preganglionic- intial efferent neuron; cell body resides with cns; all axons release acetylcholine postgangliunic neuron- cell body resides in autonomic ganglion in pns; axons travel to target cells; trigger specific changes (inhibitory or excitatory responses) by releasing either acetylcholine or norepinephrine

precentral gyrus

primary motor cortex

Cns to pns voluntary- upper motor neurons

primary motor cortex make decision to move and initiate that movement

limbic system

primitive structures involved in survival functions of memory, nutrition, and reproduction hippocampus- in temporal lobe; connected to fornic involved in memory and learning amygdala- involved in behavior and expression of emotion, especiallly fear with visceral responses

occipital lobe

process all information related to vision

sensory transduction

process where stimulus is converted into an electrical signal

deincephalon

processes, integrates and relays information, maintains homeostasis, regulates biological rhythms

cranial meninges: arachnoid mater- arachnoid granulations

project superficially through meningeal dura into the dural sinuses allow for return of CSF to bloodstream

what are the three regions of embryo brain and what they turn into

prosencephalin (forebrain) cerebrum and diencephalin mesencephalin (midbrain) midbrain rhombencephalin (hindebrain) pons, cerebellum and medulla oblangata

blood brain barrier- composition and function

protection that separates csf and brain ecf from chemicals and disease causing organisms found in blood; found throughout brain consists of simple squamous epithelial cells of blood capilarries bound together by tight junctions and astrocytes prevent fluids and molecules from passing between them allow nonpolar and liid soluble molecules

oculormotor- parasympathetic

pupillar constriction; ciliary body and control iris and lens change (accomodation)

cns to pns voluntary- lower motor neurons

receive messages from upper motor neurons; contact skeletal muscle fibers; release acetylcholine onto muscle fibers to initiate contraction

autonomic tone

refers to fact that neither division is ever completely shut down; constant amount of activity from each division sympathetic tone- dominates in blood cells; keeps them partially constricted parasympathetic tone- dominates in heart; keeps heart rate at an average of 72 beats per mintes

autonomic centers in the reticular formation in brainstem- homeostasis

regions found in reticular formation that contact hypothalamus; contains neurons that control activity of preganglionic sympathetic and parasympathetic neurons

diencephalon: thalamus

relay station that receives all sensory information except smell/ olfactory), integrates and sends information to sensory areas in cerebral cortex process information related to emotions, memory, and mood receive motor inofrmation from basal nuceli and motor cortex involved in controlling arousal, consciousness, and level of responsiveness and excitability of cerebral cortex

rapidly adapting receptors

respond rapidly with high intensity to stimuli but stop sending signals after a certain time period (called adaption) receptors detect initiation of stimuli but ignore ongoing stimuli

parietal lobe

responsible for processing and integration sensory information and function in attention

homestasis two structures of cns

reticular formation and hyptohalamus and both control ans

cranial meninges: arachnoid mater

second meningeal later; think web like membrane composed of collagen with some degree of elasticity

vestibulocochlear

sensory; equillibrium and hearing

optic nerve

sensory; structure served is retina of eye

longitudinal fissure

separates left and right cerebral hemispheres

central sulcus

separates pre and post central gyri

lateral fissure

separates temporal and parietal lobes

cranial meninges: subdural space

serous fluid filled soace; found between dura matter and arachnoid mater

innervation of axillary nerve

serves structures near axilla including deltoid and teres minor and skin over deltoid region

sulci

shallow grooves on surface of cerebrum

accessory

shrugging shoulds (sternocleidomastoid and trapezius) - motor

dermantomes

skin divided into different segments based on spinal nerve that supplies region with somatic sensation dermatome map- represents sensory pathways to differnet parts of body dermatome maps can be used clinically to test integrity of sensory pathway to different parts of body

innervation of pudendal nerve

skin of external genitalia muscles of pelvic floor

merkel cell fiber

slow adaption, discriminate touch with fine spatial resolution

nociceptor

slow adaption, pain

ruffini ending- bulbous corpuscle

slow adaption, stretch and movement

sympathetic nervous system effects on smooth muscle cells

smooth muscle cells: constriction of blood vessels serving digestive, urinary,a nd integuementary system- NE binds to alpha 1 receptors; decrease blood flow to these organs ne binds to beta 2 receptors; increase amount of air that can be inhaled with each break cardiac uses beta blockers thus heart rate, contractility and works on the heart contraction of urinary and digestive sphincters norepinephrine binds to b2 and b3 receptors which contracts them amkes empty bladder and bowel more difficult during increase physical activity relaxation of the smooth msucles of the digestive tract norepinpephrine binds to beta2 which slows digestion during increased physical activity dilarion of the pupils norepinpehrine binds to alpha 1 receptors which causes the pupil to dilate the and the pupillary muscles to contract constriction of blood vessels serving most exocrine glands (secretes through ducts) norepinephrine binds to beta 2 which decreases the secretion of saliva except sweat glands but it increases thick saliva (mucous)

trochlear

somatic motor goes to superior oblique muscle

pns: motor division (efferent)

somatic motor division: responsible for voluntary motor functions; composed of lower motor neurons (somatic motor neurons) which directly trigger skeletal muscel contraction visceral motor division (ans): responsible for maintaining homeostasis by controlling involuntary motor functions in body; neurons innervate cardiac muscle, smooth muscle, and secretion of glands sympathetic nervous system of ans- involved in homeostasis activities surrounding physical activity and visceral responses of emotions parasympathetic system of the ans- involved is digestion and maintaining bodys homeostasis at rest

PNS; sensory division (afferent) neurons

somatic sensory division: detects both internal and external stimuli; general senses recptors detect stimuli from skin, special receptors detect stimuli from special sense organs visceral sensory division: relays internal information (like blood pressure) from organs of abdominopelvic and thoracic cavities

structure of sensory neurons

somatic sensory neurons or pseudounipolar neurons with the following three main components: posterior root or dorsal root ganglion: lateral to spinal cod and cranial nerve ganglia in head and neck contain cell bodies of senosry nerve cranial nerve ganglia peripheral process of the neuron: long axon that transmits action potentials from sensory receptor to neuron's central process central process: exits cell body and travels through posterior root; enter spinal cord at posterior horn (or brainstem_ eventually synapsing on a neuron in the spinal cord or brain stem

corneal blink reflex

somatic sensory receptors of trigeminal nerve in cornea when something contacts eye leading to a blink response facial causes you to blink

photoreceptos

special sensory exteroceptors found only in eye; depolarize in response to light

somatic motor of vagus

speech because it goes to the larynx

structure of spinalnerves

spinal nerve is short and divides into the follwoing two mixed nerves, whcih both carry both somatic motor and sensory information

motor functions

stimulation of muscle contraction or gland secretion; function of peripheral nervous system

interactions of autonomic divisions

sympathetic and parasympathetic divisions work together to keep many of body's functions within their normal homeostatic ranges 1. antagonistic 2. dual innervation- both division innervate many of same organs where their action antagonize one another 3. homeostasis

2 divisions of ans

sympathetic and parasympathetic with together maintain homeostasis of vital functions: heart rate, blood pressure, digestion, and urinary processes

effexts on other cells

sympathetic nervous system influences many other target cells, all with the mission of maintaining homeostasis during increased physical otr emotion stress enhance mental alertness by increasing neuron activity in brain temporarily increases tension generation by skeletal muscle, perform unusual feats of strength under influence of an adrenaline (epipnephrine) rush increase blood tendency to clot trigger contraction of arrector pili muscles, which produces goose bumps causes ejaculation of semen via smooth muscle

role of cerebellum in voluntary movement

the cerbellum recieves input from motor areas via upper motor neurons, vestibular nuclei in the ponds and ascending sensory tracts from the spinal cord

brain waves and stages of sleep

the different stages of sleep can be monitored using and electroencephalogram or eeg, which measure the electrical activity of the brain using electrodes attached to the skin beta waves- occur when we are awake and engaged in mental activity theta waves- stages one through three of sleep delta waves- deep sleep stage 4 REM sleep- similiar to beta waves, dreaming occurs

effects on glandular epithelial cells

the parasympathetic division has little effect on sweat glands but does increase secretion production from other glands Cn VII- lacrimal Cn VII and IX- 7 salivary gland (sublingual and submandibular) CN IX- parotid CN X0 throat glands

external spinal cord

the spinal cord extends proximally from the foramen magnum to first and second lumbar vertebrae. the following structural feature can be seen on the spinal cord: posterior median sulcus, anterior median sulcus, conus medullaris, and the filum terminale. Nerve roots that project from the spinal cord fuse together to form the spinal nerves, which carry sensory and motor impulses to and from the spinak cord

relationship between thermoreceptors and nociceptors

they are both found on free nerve endings type of thermoreceptors- usually small knobs at end of free nerve endings in skin cold recepors respond to temperatures between 10C and 40C in superficial dermis

role of basal nuclei in voluntary movement

three collections of cell bodies make up basal nuceli: caudate nucleis, glous pallidus and putamen substantia nigra midbrain words closely with basal nuceli: secretes dopamine basal nuclei modify activity of upper motor neurons to stimulate voluntary movements and inhibit involuntary ones damage to the basal nuclei or substantia nigra lead to movement disorder

cervical and lumbar enlargement

to hold the body up they dont crush each other

trigeminal

tongue, gums, cheeks

spinal cord

tracts and neuron cell bodies enclosed in protective vertebral cavity; connects to inferior portion of brainstem; ends between first and second lumbar vertebrae

spinal cord: descending tracts

transmit motor information from specific regions in brain spinal cord to specific regions in bodys

posterior columns/ medial lemnsical system

transmit tactile information about discriminative touch conveying information regarding proprioreceptors first order neurons- ascend through posterior columns second order neurons decussate and form tracts called medial lemniscus (medullar oblongata) that ascend through ponds and midbrain to thalamus third order neurons in thalamus proceed to primary somatosensory cerebral cortex (post central hyrus)

spinal cord: ascending tracts- spinothalamic tracts of the anterolateral system

travel in anterior and later funiculi; transmit pain and temperature stimuli from entire body to brain

anterior ramus

travels to anterior side of body and or to an upper or lower limb

posterior ramus

travels to posterior side of body

mixed cranial nerves

trigeminal, facial, glosspharyngeal, vagus

cerebellum: cerebellar hemispheres

two cerbellar hemispheres connected by structure called vernis

exterorecptors

usually close to body's surface; detect stimuli originating from outside body

interoreceptors

usually found within body's interior; detect stimuli originating from within body itself

nociceptors

usually slowly adapting exteroreceptors; depolarize in response to noxious stimuli and pain

branches and extends to thoracic and abdominal

vagus

cranial meninges: dura mater- dural sinuses

venous channels found between dura that drain CSF and deoxygenated venous blood

autonomic nervous system

visceral motor division involuntary peripheral nervous system

gag reflec

visceral sensory nerve endings of glossopharyngeal nerve in posterior throat are stimulated and vagus

brain regions that are required for communication

wernickes- understanding speech brocas- ability to speak aphasia- language deficit

extra pathway of cns to pns

when control center decides on a motor program the upper neurons in the premotor cortex select and the send signals to the basal nuclei and the basal nuclei will be activated and the globus pallidus will be stimulated and the thalamus is activated then goes from cns to pns through descending tracts from the lower motor neuron tot he skeletal muscle then sends sensory information through first order, second order, and the spinocerbellar pathway (two neuron pathway) to the cerebellum then the cerebellum modifies by comparing the planned movement to the movement that was executed then fires down again then a nice smooth movement

cerbellum: arbor vitae

white matter

medulla oblongata: posterior columns

white matter carry sensory information from spinal cord

brainstem: ascending and descending tracts (cerebral penducles)

white matter tracts

white vs gray matter in the cns

white matter- found in both brain and spinal cord; consists of myelinates axons cerebrum and spinal cord contain bundles of white matter called tracts; contains clusters of cell bodies and dendrites in cerebral gray matter called nuclei cerebral white matter deep in brain is called medulla. Spinal cord superficial white matter called columns gray matter- found in both brain and spinal cord; consists of neuron cell bodies, dendrites and unmyelinated axons outer cerebrum is gray matter called cortex clusters of cell bodies and dendrites in cerebral gray matter called nuclei spinal cord gray matter in horns (in cord center)

describe the two basic types of memory and give three examples

• Declarative: fact - defined as memory of things that are readily available to consciousness; could in principle be expressed aloud • Phone number, a quote or pathway of corticospinal tracts, fimation of these memories requires rhe hippocampus, being able to name all the glee casts • Nondeclarative: memory procedural or skills includes skills and assocaitiont hat are largely unconscious • how to enter phone number on, how to move your mouth to speak, and how to read this chapter, being able to distinguish between pepsi and coke, formation of these memories requires the cerebellum, memories associated with emotions persist longer, making a sandwich

what are the three classifications of memory

• Immediate memory: stored only for a few seconds; is critical for carrying out normal conversation, reading, and daily tasks • Short-term (working) memory: stored for several minutes; allows you to remember and manipulate information with a general behavioral goal in mind • Long-term memory: a more permamnent forma storage for days, weeks, or even a lifetime

protection of spinal cord: 3 actual or potential spaces from superficial to deep

• Spinal cord - composed primarily of nervous tissue; responsible for both relay station between body and brain and processing station of spinal reflexes. • Spinal meninges (Figure 12.26) include dura mater (only a meningeal layer), arachnoid, and pia mater; structurally similar to brain meninges • Epidural space-filled with veins and adipose tissue; cushions and protects spinal cord • Subdural space-potential space • Subarachnoid space-found between arachnoid and pia mater; filled with CSF; site for withdrawing samples for clinical laboratory testing by lumbar puncture