276 terms

Unit 9 Neuro-sensory

The Brain
Occupies cranial cavity, covered by membranes, fluid and bones of the skull.
The cerebrum
- largest part of the brain.
Cerebral hemispheres
- divided into right and left.
Longitudinal fissure
- deep groove that divides.
-area between the cerebral hemispheres and the brain stem. Includes thalamus and hypothalamus
Brain stem-
connects the cerebrum and diencephalon with the spinal cord.
- superior portion of brain stem
- inferior to midbrain
Medulla oblongata
- pons connects midbrain with medulla
Foramen magnum
- medulla connects the brain with the spinal cord through large opening at base of the skull.
- (little brain) located immediately below the posterior part of the cerebral hemispheres, connected with cerebrum, brain stem and spinal cord by means of the pons.
3 layers of connective tissue that surround both the brain and spinal cord to form a complete enclosure.
Dura mater
- outermost - thickest, toughest (hard mother) has 2 layers and outer layer is fused to bones of cranium.
Dural sinuses
venous channels for drainage of blood coming from the brain tissue.
middle layer of meninges. Loosely attached by weblike fingers. Allows space for movement of CSF cerebrospinal fluid.
Pia mater
innermost layer around the brain ,Attached to nervous tissue of the brain and spinal cord. Follows all contours.,Delicate connective tissue. ,Holds blood vessels,Supply nutrients and oxygen to brain and spinal cord.
Cerebrospinal fluid
Clear liquid that circulates in and around the brain and spinal cord.
Function of CSF
to support nervous tissues, cushion shocks, carries nutrients to cell, transports waste away.,Flows out into subarachnoid space of the meninges.
Arachnoid villis
rojections through which fluid returns to blood.
- 4 spaces within the brain.
Choroid plexus
-vascular network in each ventricle- forms CSF by filtration of the blood and by cellular secretion.
extensions into lobes of cerebrum
openings for communication.
Cerebral aquaduct-
continues down from 3rd ventricle- small canal.
Cerebral Hemispheres: Divided into 4 lobes:
frontal, parietal, temporal and occipital lobes.
small 5th lobe- deep within each hemisphere-
Cerebral cortex-
outer nervous tissue of the cerebral hemisphere is gray matter. Arranged in folds. Thin layer of gray matter- most highly evolved portion of brain, Responsible for conscious thought,reasoning, and abstract mental functions.
elevated portions of folds.
Sulci- (sulcus)
Raised areas are separated by shallow grooves
Central sulcus-
lies between frontal and parietal lobes of each hemisphere at right angles to the longitudinal fissure.
Lateral sulcus-
curves along the side of each hemisphere and separates the temporal lobe from the frontal and parietal lobes.
White matter-
Internally- cerebral hemispheres are made of white matter.Consists of myelinated fibers that connect the cortical areas of each other with other parts of the nervous system.
Basal nuclei-basal ganglia-
masses of gray matter located deep within each cerebral hemisphere.,Work w/cerebral cortex to regulate body movement, muscles of facial expression.
neurotransmitter secreted by neurons of basal nuclei.
Corpus callosum-
band of white matter located at bottom of longitudinal fissure.,Band is a bridge between right and left hemisphere. ,Permits impulses to cross from one side to the other.
Internal capsule-
compact band of myelinated fibers that carries impulses between the cerebral hemispheres and the brain stem.
Vertical fibers
make up internal capsule
cerebral cortex-
layer of gray matter forms surface of each cerebral hemisphere-impulses are received and analyzed.
Functions of Cerebral Cortex
Activities form the basis of knowledge. ,Memory- information can be recalled on demand.,Thought processes such as association, judgment and discrimination.,Conscious deliberation and voluntary actions
Frontal lobe-
larger in humans- lies anterior to the central sulcus.
Frontal Lobe Functions
Primary motor area- provides conscious control of skeletal muscles.,2 areas important in speech.
Parietal lobe-
occupies superior part of each hemisphere and lies posterior to the central sulcus.,Gyrus just behind the central sulcus in this lobe contains:
Parietal Lobe Functions
Primary sensory area- impulses from the skin : touch, pain, and temperature are interpreted. ,Estimation of distances, sizes and shapes take place here. Greater the sensation the more involved cortex is.
Temporal lobe-
inferior to lateral sulcus, fold under the hemisphere on each side.
Temporal Lobe Functions:
auditory area- receiving and interpreting impulses from the ear.Olfactory area- sense of smell- located in medial part of temporal lobe. Stimulated by impulses arising from receptors in the nose.
Occipital lobe- l
ies posterior to theparietal lobe and extends over the cerebellum.
Occipital lobe functions
Visual receiving area and visual association area, Interprets impulses arising from the retina of the eye.
Auditory areas-
lie in temporal lobe-
Auditory receiving area-
detects sound impulses transmitted from the environment
Auditory association area
- interprets sounds.
Speech comprehension area-
wernicke area- functions in speech recognition and the meaning of the words.auditory
Motor areas-
for spoken and written communication- lie anterior to the most inferior part of the frontal lobe's motor cortex.
Motor speech area.
- broca area- Speech muscles in the tongue, soft palate, and larynx controlled here.
Motor aphasia-
difficulty producing speech ( if damage to this area)
Written speech center-
lies anterior to cortical area that controls arm and hand muscles. motor
Ability to write words-
last phase of development of learning words and their meanings.Motor
Visual areas-
occipital lobe's cortex.
Functions of Occipital lobe cortex
Visual images of language are received. Visual area lies anterior to receiving cortex, then interprets these visual impulses as words. Ability to read with understanding develops in this area.
mental faculty for recalling ideas.
Initial stage-
sensory signals are retained for a short time.
Short term memory
- retention bits of information for a few seconds or perhaps a few minutes. After that time information is lost unless reinforced.
Long term memory-
storage of information that can be recalled at a later time.
Fibrils form at
the synapses in the cerebral cortex. ,Enables impulses to travel more easily from one neuron to another.
interbrain- is located between the cerebral hemispheres and the brain stem.,Includes thalamus and hypothalamus. 2 parts of the thalamus form the lateral walls of the third ventricle.
All sensory impulses travel through the thalamus.
Role of thalamus
is to sort out the impulses and direct them to particular areas of the cerebral cortex.
Located in the midline area inferior to the thalamus and forms the floor of the third ventricle.
Hypothalmus Helps maintain
homestasis by controlling body temperature, water balance, sleep, appetite and some emotions such as fear and pleasure.
Hypothalmus Controls-
Sympathetic and parasympathetic, controls pituitary, Influences heartbeat, Contraction and relaxation of blood vessels. ,Hormone secretion,Other vital body functions.
The Brain Stem
Composed of midbrain, pons and medulla oblongata.
Inferior to the center of the cerebrum.,Forms superior part of brain stem.
Mid brain Gray Matter
-Four rounded masses, hidden by cerebral hemispheres form superior part of midbrain.,Four bodies act as centers for reflexes involving,Eyes, and ears.
Midbrain White matter - anterior of midbrain
- conducts impulses between higher centers of cerebrum and lower centers of pons, medulla, cerebellum and spinal cord.
Crainial nerves III and IV
originate from midbrain.
The Pons
Lies between the midbrain and the medulla ,Anterior to the cerebellum ,Composed of myelinated nerve fibers which connect the tow halves of the cerebellum with the brain stem,
Pons is an Important connecting link
between cerebellum and rest of nervous system.
Pons regulates
Reflex- involuntary actions- some regulating respiration.
Cranial nerves V through VIII
originate from Pons.
Medulla Oblongata
Located between the pons and the spinal cord. ,Appears white externally because of myelinated nerve fibers., Internally contains collection of cell bodies( gray matter) called Nuclei or centers. Vital centers.
Medulla Oblongata Controls
Respiratory center- Cardiac center- Vasomotor center Controls blood flow and blood pressure.
Hair Follicle
Composed of Keratin , not living, Filament, slender, dead, epidermal tissue
Hair All over the body except
soles of feet
Arrector pili
surrounds base of hair, band of muscle, contracts- goose bumps-Cells add color pigment to hair.
Hair is Protection
for eyes and nose
Hair follicles
are located Deep in dermis and subcutaneous tissue.
Dead, Cutaneous plates , made of keratin - produced by cells that originate in the outer layer of the epidermis, Protection- for toes and fingers
Nails originate
in outer part of epidermis
1. Affect
*Emotional state- can be created by nervous system. To have an influence on or affect a change in.
2. Arachnoid
*middle layer of meninges. Resembling a cobweb. Used of the arachnoid membrane covering the brain and spinal cord.
3. Auditory
**pertaining to sense of hearing. Of or relating to hearing, the organs of hearing, or the sense of hearing.
4. Brain Stem
**portion of brain that connects the cerebrum with the spinal cord, contains the midbrain, pons, medulla oblongata. the stemlike portion of the brain connecting the cerebral hemispheres with the spinal cord.
5. Cerebrum
**largest part of brain. the main portion of the brain, occupying the upper part of the cranial cavity; its two hemispheres, united by the corpus callosum, form the largest part of the central nervous system in humans.
6. Cerumen
earwax; the waxlike substance found within the external meatus of the ear.
7. Cutaneous
**skin pertaining to the skin.
8. Dura mater
**outermost layer of meninges the outermost, toughest of the three meninges (membranes) of the brain and spinal cord.
9. Effect
**response to a stimuli, the result produced by an action.
10. Equilibrium
**state of balance. the condition of balance between varying, shifting, and opposing forces that is characteristic of living processes.
11. Grey Matter
**nervous tissue, composed of unmyelinated fibers and cell bodies. Brownish-gray nerve tissue, especially of the brain and spinal cord, composed of nerve cell bodies and their dendrites and some supportive tissue.
12. Hypothalmus
** region controls pituitary, maintains homeostasis. The part of the brain that lies below the thalamus, forming the major portion of the ventral region of the diencephalon, and that regulates bodily temperature, certain metabolic processes, and other autonomic activities.
13. Motor
**efferent neurons, fibers that carry impulses from the central nervous system out to muscles and glands. Causing or producing motion.
14. Neurology
** study of diseases of nervous system. the branch of medicine that deals with the nervous system, both normal and in disease.
15. Olfactory
*cranial nerve, sense of smell. Receptors in nasal muscosa. Of, relating to, or contributing to the sense of smell.
16. Orbit
Eye socket. the bony cavity containing the eyeball and its associated muscles, vessels, and nerves.
17. Receptor
Specialized cell or ending of sensory nerve that can be excited by a stimulus. a sensory nerve ending that responds to various stimuli.
18. Refraction
** bending of light rays as they travel through a medium other than air. the deviation of light in passing obliquely from one medium to another of different density.
19. Sensory
**neurons that carrie impulses from receptors, to the brain and spinal cord. Transmitting impulses from sense organs to nerve centers; afferent.
20. Synapse
**point of junction between 2 neurons or between a neuron and an effector. Carries Out a response to stimulus. (leaping)the site of functional apposition between neurons, where an impulse is transmitted from one to another, usually by a chemical neurotransmitter released by the axon terminal of the presynaptic neuron.
21. Thalmus
**region of brain located in diencephalon- A large ovoid mass of gray matter situated in the posterior part of the forebrain that relays sensory impulses to the cerebral cortex.
22. White Matter
Whitish nerve tissue, especially of the brain and spinal cord, consisting chiefly of myelinated nerve fibers. ** nervous tissue composed of myelinated fibers.
Nervous System-
coordinates and controls the body, then communicates with systems, That will conduct responses to internal and external changes.
Functions of Nervous system
Reacts to internal and external changes,Links with environment,Center of mental processes., Reacts in split seconds. Processes information and sends it to an appropriate area.
CNS- -central nervous system
Brain, spinal cord
PNS- pheripheral nervous system-
spinal nerves, cranial nerves
Effectors areskeletal muscles, Controlled voluntary, conscious will.
Autonomic- automatic-
involuntary-,Activities of visceral organs
Autonomic Nervous System Processes:
Hormonal feedbacks, visceral , controls smooth muscle, heart glands, peristalsis, digestive juices.
Autonomic breaks into
Sympathetic, Parasympathetic
Role of nervous system:
Detects and responds to stimuli, Brain and spinal cord act as switiching centers,Nerves carry messages to and from centers.
Functional cells of nervous system, Extremely specialized
Structure of a neuron
Cell body,Nucleus, Cell fibers,Dendrites,Axons
Neuron Nerve cells are
transmitter cells
nerve fibers move toward the cell.
nerve fibers that carry away from the cell.
This equals neuron-
dendrites and axons
Types of neurons:
Can be sensory or motor
Nerve tissue:
neurons a lot of them together form bundles = nerve fibers.
Nerve Fibers are like
a conducting core
sensory- impulses -Electrical charge- goes toward central nervous systems- Incoming
-motor- comes away from CNS- outgoing
mixed combo of sensory and motor ( central neurons and associative) found ONLY in CNS.
Afferent- Sensory-
single dendrite -single axon
can be up to 3ft. long.,Sent to brain, interpret, response. Stimulus happens within seconds
Dendrite orginates in
Receptors are
end organs- internal and external-, all information send to brain and right back out (effector).Touch, pain, hot and cold. Etc.
long axon and 3-5 dendrites, Myelin sheath- Nerve fibers are covered with Myelin.
Myelin is an
Myelin Covered by
neurilemma - connective tissue,Regenerates nerve tissue.
***CNS does not have
nurilemma- cannot regenerate.
Synapse- junction-
Gap between nerve tissue-,Impulse will jump across,Electricity- junction point for transmission of nerve impulses.
Synapse Needs neurotransmitters:
ephinenphrine(norephinephrine), acetycoline,(adrenaline) noradrenaline, Need chemical to send it to the brain.
Gray Matter
- concerned with brain and spinal cord, unmyelinated; no neurilemma, Taking impulses across selected synapses,Tissue, cell bodies of these neurons are scattered throughout., Several cell bodies- constantly conducting.,Hit with stimuli all the time. Brain very active
White Matter
Myelinated, Concerned with impulses along fibers which goes both ways. Spinal cord- has tracks- bundles of nerve fibers which have the same origin and termination and function.
Nervous system at work
Electrical impulses sent along neuron fibers and transmitted between cells at junctions.
Connective tissue - 3 layers, surround brain and spinal cord, forms a closed system
outermost layer, thickest, toughest, protection.,In spine- lines vertebrae,In brain- skull splits to allow passage of blood
Arachnoid membrane-
cobweb-w/spaces in between- to hold fluid
Subarachnoid space-
cerebral, spinal fluid.-CSF
Pia mater-
allows for blood supply to the brain.,Directly attached to the cord and the brain.,Will dip in and out of brain- into all of those depressions.Extremely delicate. - a lot of vessels.
Cerebrlspinal Fluid
Cushion, protect, transport nutrients and waste ( away.) Supports nervous tissue, cushions from shock
Choroid plexus-
forms CSF-formed by filtration of the blood and any cellular secretions (made) of clear fluid ; inside ventricles.
Cerebral Spinal Fluid - absorbs back into body through
arachnoid villi
How do we make CSF?
choroid plexus (ventricles)
filled with CSF( spinal fluid), system will flow into subarachnoid spaces
Cerebral hemispheres, Longitudinal fissure, Lobes
Thalamus, and Hypothalamus
Brain stem
Midbrain, Pons, Medulla oblongata
Left side controls right,
largest part of brain,Has 2 hemispheres - right and left, Center for all of our higher function, Thinking, reasoning, memory, judgement Responsible for our personality
cerebral cortex-
outer nerve tissue. Covers cerebrum
Gray matter-
Folds are called gyrate
Grooves are called sulci
Convolutions -
Elevated portions
Dipping down
Corpus collosum-
connects he hemispheres- the corpus collosum-
Frontal lobe-
motor cortex
Frontal Lobe Controls
voluntary muscle action.,Motor ability includes:,Writing,Speaking,Intellectualization,judgement,Forming concepts,Critical thinking, Controls speech
Upper part of each hemisphere Sensory area- interprets our general senses: Heat,cold, shape, feel ,distance, size, pain, touch,temperature,shapes,Help us to recognize body parts.-
Temporal lobe-
ears, auditory center, Memory storage, Smell
Occipital lobe-
most posterior, extends over cerebellum, Visual receiving area ,Interpret messages we get from eye to retina.,Involved with understanding the written word.
Brain Stem-
Midbrain, pons, and medulla oblongata
just below cerebrum- forward part of brain stem.
Midbrain Function-
relay center for eye and ear reflexes,Serves as passageway to the higher brain centers, Conducts impulses from cerebrum down through midbrain, pons, medulla to spinal cord.
means bridge,White matter,Connects midbrain to medulla, link to cerebellum and rest of nervous system, Myelinated fibers,Transmits impulses to cerebellum to the cerebrum, maybe medulla to the spinal cord.
Pons has
reflex action, Partial control of respirations.
Medulla oblongata
Between pons and spinal cord,White outside ; gray inside
Medulla oblongata is
at Distal part of brain stem
Medulla Oblongata controls
Respiratory center, controls muscles of respiration , Cardiac center- ,Vasomotor center- vessels, determines BP, Reflex action- hiccup, cough, sneezing, vomitting
Functions Of Ear :
Organ for hearing, equilibrium
external auditory canal, tympanic membrane
Functions of Pinna-
oracle-, Captures sounds,Visible portion of ear,Made of cartilage,Directs soundwaves
External auditory canal-
meatus, Inch long, Lined with cilia
ear wax; cerimonous glands,Will conduct sounds to tympanic membrane,Protects typanic
Tympanic membrane-
creates tympanny- drums,Vibrates as sound enters ear, Vibrates and transmits sound waves to ossicles, Ear drum
Tympanic Membrane Covered with
skin on outside, Thin mucous membrane on inside, Separates external ear from middle ear.
Middle ear-
air filled chambers- found in temporal bone of skull.
smallest bones in our body 3 0f them, sealed off by tympanic membrane, these bones move, amplify and transmit , vibrate, conduct sound waves through middle ear to oval window or
oval window-
(foramen ovale- entrance to middle ear)
After foramen ovale is a vestibule
hammer- looks like hammer
Eustachian Tube
connects middle ear to pharynx (throat), equalizes pressure on both sides of tympanic membrane,mucous membrane from pharynx to middle ear cavity.
Inner Ear
3 spaces- hollowed out inside the temporal bone.,Series of canals
contains receptors for hearing., Receptors organ of corti- organ of hearing.,Effected by gravity- keeps you on your feet.
Bony labyrinth
Vestibule- entrance through oval window into chochlea
Semicircular canals-
right angled - contains perilymph- for equilibrium
Vestibular nerve and cochlear nerve will merge into one and make up the main nerve
cranial nerve 8 vestibulocochlear nerve 8 - (acoustics)
organ of corti-
receptor cells where we are REALLY going to hear.
Taste buds on tongue
Stimulated by substances in solution
Basic tastes buds
- along fissures of tongue
tip of tongue, middle, behind salt.
tip at -very tip.
Cranial nerves of taste buds and mouth
Facial (VII), Glossopharyngeal (IX)
Sense of Smell
Smell receptors in nasal cavity
Smell receptor
olfactory 1 found in nasal cavity, send off to olfactory nerve and off to the brain, Found in upper part of nasal cavity- mucosa, Stimulates appetite
Fit into a cavity in skull.- protects Eye cavity bones protection of eye eyelid, eyelashes and eyebrown, conjunctiva, lacrimal
mucous membrane, Lining of eyeball.
Lacrimal gland
tears -wash away what might get in your eye, Cleansing mechanism
Layers of eyeball-
coats, tunics, layers- 3 layers
- coats- outermost layer-, white of eye,Toughest, protective,Covers front of eyeball.
sclera becomes transparent, window of our eye.
very vascular, 2nd tunic layer, attached to eye muscle
Ciliary muscle-
attaches choroid, contracts-
color pigment of eye-, regulates the size of the pupil.
Suspensory ligament-
holds lens in place. By means of filaments.
brings light into focus
size of Iris opening- opening of eye, lens fits into pupil-bringing light into focus.
3rd layer, Vision takes place
nerve receptor that will pick up light when it is dim. (night),Sensitive to black and white
will be in bright light or color. (day),Sensitive to color
Made up of 3 parts- middle portion (vermis) and two lateral hemispheres.
Outer area of gray matter and Inner area of white matter which has treelike pattern.
Functions of cerebellum
Balance, muscle tone, coordination, standing, walking, sitting
Cranial Nerves
12 pairs of these nerves.
Cranial nerves
Numbers begin anteriorly and proceed posteriorly,All arise from brain stem EXCEPT the first 2 pairs, and 9th pair and 12th pair supply structures of the head.
Special sensory impulses of cranial nerves
smell, taste, vision, and hearing.
General sensory impulses of cranial nerves
pain, touch, temperature, deep muscle sense, pressure and vibrations and are Widely distributed throughout body.
Somatic motor impulses of Cranial Nerves
Voluntary control of skeletal muscles.
Visceral motor impulses of cranial nerves
Produced involuntary control of glands and involuntary muscles. ( cardiac and smooth)
Motor pathways part of autonomic nervous system
parasympathetic division.
Cranial nerves Contain on sensory fibers
Cranial nerves Contain motor fibers
Cranial nerves Contain both motor and sensory
I - olfactory nerve(cranial)
carries smell impulses from receptors in the nasal mucosa to the brain.
II- optic nerve(cranial)
carries visual impulses from the eye to the brain.
III- oculomotor nerve(cranial)
concerned with the contraction of most eye muscles.
IV- trochlear nerve(cranial)
supplies one eyeball muscle.
V- trigeminal nerve(cranial)
large sensory nerve of the face and head.
Trigeminal nerve
3 branches transport general sense impulses From eye, upper jaw, and lower jaw ,// pain, temperature, touch
Trigeminal nerve
motor fibers to the muscles of mastication join the third branch, This nerve dentist anesthetizes to work on teeth.
VI- abducens nerve(cranial nerve)
sends controlling muscles to an eyeball muscle.
VII- facial nerve(cranial nerve)
largely motor- muscles of facial expression and includes special sensory fibers for taste
Facial nerve VII
Contains secretory fibers to the smaller salivary glands Anterior 2/3 of tongue and Secretory fibers lacrimal glands.
VIII- vestibulocochlear nerve(cranial nerve)
carries sensory impulses for hearing and equilibrium from inner ear (Formerly called auditory or acoustic nerve)
IX-glossopharyngeal nerve(cranial nerve)
general sensory fibers from the back of the tongue and pharynx- SWALLOWING muscles, secretory fibers supply the largest salivary gland(parotid)
X- vagus nerve
longest cranial nerve. ( name means wanderer) Supplies most of the organs in the thoracic and cavities.
X vagus nerve
Motor fibers to the glands that produce digestive juices.
XI- accessory Nerve
(formerly called spinal accessory nerve) Motor nerve with 2 branches.
XI accessory nerve
One branch controls 2 muscles of the neck: the trapezius and sternocleidomastoid: other branch controls muscles of the larynx
XII- hypoglossal Nerve
carries impulses controlling muscles of the tongue, visceral, movement of tongue
study of skin
Thickest layer of skin
soles of feet
Thinnest layer of skin
Functions of skin
alerts body to whatever the environment is telling. (environmental conditions)
refers to skin
Skin functions
Protects against infection, dehydration, Regulates body temp, Collects sensory information
Skin functions
Protection, chemically and mechanically, light barrier, cushions internal organs (adipose tissue), Excretion- water and salt through perspiration, Absorption- minimal amounts of water, Sun- Vit D.
regulates body temperature- gets rid of heat by evaporating body sweat- cooling mechanism.,Fat layer is insulator of heat loss. - warming mechanism, Receives environmental information- part of protection
Skin consists of 3 layers
Epidermis and Dermis, subcutaneous
Outermost layer- NO blood vessels,Constantly shed- dropping epidermis,Cells are very flat.- horny, Tough and dry,Stratified, squamous,Contains our pigment
Pigment granules in epidermis
Dermis (corium)
Middle layer,Framework of connective tissues, Blood vessels, glands , nerve fibers, beginning of hair follicles., receptor organs, Receptor organs- nerves, Feel pain, hot cold, touch, pressure.
sweat, located in dermis and subcutaneous tissue
mammary glands
glorified sweat glands.
Ceruminous glands
sweat glands in ear, ear wax
lubricates skin and hair, eye lubrication
Dermis has
Blood vessels, nerve endings and gland/ Collagen- gives skin strength and flexibility
TRUE SKIN,Thickest layer,Dermal papilla
Connects dermis to muscle and Composed of elastic plus fiberous connective tissue
Subcutaneous layer
Composed of adipose tissue,Acts as an insulator, Stores energy, contains superficial fascia- protects organs -sits on top of organs.
Subcutaneous layer Function
Stores water and fat,Insulates body, Protects underlying organs Pathway for our nerves and blood vessels.