Exam 4 brain and spinal cord

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Brain

3 lbs.

Gyrus or convulsion

Folds in the brain

Sulcus

Shallow area

Fissure

Deep area

Longitudinal fissure

Separates into left and right hemispheres, connected by the corpus callosum

Central sulcus

Coronal plane (frontal from parietal)

transverse fissure

cerebrum and cerebellum

lateral fissure

separates temporal lobe

cerebral cortex

the surface of the brain. Consists of gray matter. 75% of cell bodies

frontal lobe

anterior to central sulcus
Motor
consists of three sections. Prefrontal lobe, premoter area, and precentral gyrus

prefrontal lobe

analysis , reasoning, emotions, behavior, personality, judgement

precentral gyrus

voluntary muscle actions
begins motor impulses
-left controls right side of body and vice versa

premotor area

broca's area (language and speech)
organization of groups of muscles, largely automatic eye and writing

Parietal Lobe

behind central sulcus

post central gyrus

parietal lobe
sensory
senses of temperature, touch, pressure, pain, muscle and position and some taste
wernicki\e's area (interp. of speech)

Temporal lobe

below lateral fissure
Sensory
Hearing and smell interp.
learning and memory ( with hippocampus)

occipital lobe

Sensory
sense of vision

mamillary bodies

relays limbic (sleep) and memory

olfactory bulb

interprets smell.
Under frontal lobe

association areas

50% of cortex
General interpretations and complex memories.
thinking, memorization. Basically associating information.

White matter of the cerebrum

commisural fibers
projection fibers
association fibers
basal nuclei or ganglia

commisural fibers

between hemispheres through corpus callosum(bridge)

corpus callosum

connecting the left and right hemispheres

projection fibers

vertical
brain talking to the rest of the body
(up and down)

association fibers

communication within the same hemisphere

basal nuclei (ganglia)

gray areas (muscle coordination)

gray areas

amygdala
hippocampus

amygdala

limbic system (Behavior)- memory (also the fear center for ptsd

hippocampus

memory
limbic system
input for hypothalamus
major memory relay center

Brainstem

Automatic reflex (not so much thinking)
consists of the Diencephalon (thalamus and hypothalamus), midbrain, pons, medulla oblongata

thalamus

sensory relay center (gateway to the cortex)
crude sensation
relaying information to the specific lobe

parts of the thalamus

medial geniculate body- hearing
lateral geniculate body- vision

pineal gland

roof of thalamus
area for melatonin

hypothalamus

input and output center
cardiac and vasomotor center (bp and heart reg), body temp., hunger and satiety, control asn, control pituitary (hormones), emotions (sex drive), RAS system, body fluid balance, SCN (biological clock

midbrain

(3 & 4 cranial nerves)
main motor pathway- reflexes for equilibrium and posture

pons

(5,6,7,8 cranial nerves) BRIDGE
respiratory centers
relays to cerebellum

medulla oblongata

(9,10,11,12 cranial nerves)
cardiac, vasomotor, respiratory centers
cough, sneeze and swallow reflex
crossing over of motor fibers

cerebellm

miniature brain
consists of purkinje cells and the arbor vitae(tree of life)
functions: equilibrium, coordination, position, muscle tone, plans and predicts movements, monitors and mediates reflexes, input from cerebrum, evaluates performance

meninges

membrane covering brain and spinal cord (CNS)
contains the dura mater, arachnoid, and pia mater

dura mater

connective tissue
outer most layer (protective membrane)
epidural and subdural space

arachnoid

extensions of CSF
vill into dura mater into venous sinuses where CSF enters blood
arachnoid villi is the exit for the fluid

pia mater

right on the surface of the brain and spinal cord
blood vessels-become choroid plexus) its kind of like ceran wrap

cerebrospinal fluid

60-150 ml presents but 500 ml made per day
colorless- protection and transport, stable ionic balance

ventricles

cavities in the brain for CSF
there are four
first and second- choroid plexus (70%of CSF)
then through the inter ventricular foramen to the the third ventricle- choroid plexus where CSF is made by Ependymal cells. Then through the cerebral aqueduct to the fourth ventricle. It then circulates from ventricles to other foramen to arachnoid layer to the central canal

special systems

RAS- reticular activating system
Limbic system

RAS

continuous impulse- maintains muscle tone and posture
(reflex control) alertness, filter for sensory information, modulates pain
your wake alert system-allows you to concentrate on one thing at a time

Limbic System

emotions and behavior
hypothalamus -cerebrum,hippocampus, and amygdala

special systems structure

gray matter inside and white matter outside and continues down the spinal cord.

2 types of cells in nerve tissue

glia and neuron

2 parts of the cerebrum

cerebral cortex and white matter

the base nuclei functional in memory are

amygdala and hippocampus

a wrinkle or fold in the cerebrum

gyrus

white matter contains 2 areas

basal ganglia and tracts

the outer mm's of the cerebrum is

cortex

the gray areas in the white matter of the cerbrum

basal ganglia

what speech area is in the parietal lobe

wernicke's area

which part of the brain controls body fluid balance

hypothalamus

the descending motor fibers for muscle movement cross over in the

medulla oblongata

what part of the brain controls pituitary gland

hypothalamus

the sensory relay center

thalamus

2 areas for respiritory

pons and medulla

2 areas have cardiac and vasomotor centers

hypothalamus and medulla

where are sensory impulses relayed to

cerebrum

which part of the brainstem that controls balance and position

midbrain

which part of the brainstem is known as middle management

cerebellum (its the input of the cerebrum)

Peripheral Nervous System

cranial nerves

Nerves

bundles of neurons(axons) enveloped by membranes

what are the membranes in nerves

Endoneurium
Perineurium
Epineurium

what type are nerves in the PNS

motor, sensory or mixed

how many cranial nerves are there

12

1st cranial nerve

Olfactory- Smell
sensory

2nd Cranial nerve

Optic- Vision
sensory

3rd cranial nerve

Oculomotor- moves the eye and lid
constricts and dilates pupil and adjusts lens
MOTOR

4th cranial nerve

trochlear- moves the eye
MOTOR

5th cranial nerve

trigeminal- sensations of the face and taste
muscles for chewing
MOTOR AND SENSORY

6th cranial nerve

abducens- moves eye
MOTOR

7th cranial nerve

Facial- for taste, facial expression muscles, for salivary and lacrimal glands (crying, drooling smiling and tasting)
MIVED

8th cranial nerve

auditory- (vestibulochlear) hearing and balance
SENSORY

9th cranial nerve

glossopharyngeal- for tastes, move the tongue to swallow (salivary gland)
MIX

10 cranial nerve

Vagus- taste, speaking and swallowing muscles, major nerve of the parasympathetic system. and longest cranial nerve
MIX

11th cranial nerve

accessory- motor to muscles and neck

12th cranial nerve

Hypoglossal- move the tongue and swallow
MOTOR

central nervous system

spinal cord

three main functions of the spinal cord

pathway for motor and sensory information
site for spinal reflexes
contains the center of walking

structure of the spinal cord

extends to second lumbar vertebrae
gray matter is called horns
white matter is called columns (myelinated)

three ascending tracts of the spinal cord

cuneate
spinothalamic
spinocerebellar

two descending tracts of the spinal cord

(MOTOR)
corticospinal
reticulospinal

cuneate tract

position and touch

spinothalamic

pain and temp

spinocerebellar

sense of position and muscles (sensations)

corticospinal

movement of skeletal muscles

reticulospinal

involuntary muscle tone and posture- maintain balance

how many spinal nerves are there

31
cervical-8
thoracic-12
lumbar-5
and sacral 6

a collection of nerves

plexus

the nerve in the cervical plexus

phrenic nerve (breathing nerve)

nerve in the sacral plexus

sciatic nerve (largest nerve in the body)

plexus for the arm

brachial

cauda equina

known as the horse tail
ends of spinal nerves below the cord
it hangs of the end of the spinal cord

two roots in the cord

dorsal root- SENSORY
ventral root- MOTOR

rami

branches of spinal nerves

posterior ramus

branch to back of body

anterior ramus

branch to front of body

somatic reflex

(spinal reflex)
a stimulated response (not thinking reflex)
receptor in muscle to dendrite of sensory neuron to dorsal root to cell body to axon of sensory neuron to spinal cord interneuron to dendrite to cellbody of motor neuron to axon of motor neuron to ventral root to muscle

Autonomic system

the motor system coming down from the brain.
self controlled reflexes. Involuntary impulses to smooth and maintains homeostatis
SMOOTH, CARDIAC MUSCLES AND GLANDS

2 neurons in the autonomic system

preganglionic and postganglionic

rami (circuits) in the autonomic systems

go into or out of ganglion (neurons can synapse, converge or diverge)

2 divisions of the autonomic system

parasympathetic
sympathetic

parasympathetic

replenishes body supplies, conserves energy
cranial nerves- 3,7,9,10 (90% is VAGUS)
function- slow heart rate down, slow breathing down, stimulates digestive system, stimulates urinary system, constricts pupil in the eye. stimulates more liquid from the salivary glands and constricts airways

the neurotransmitter for the parasympathetic system

acetylcholine

the neurotransmitter for the sympathetic division

norepinephrine

sympathetic system

stress, 'flight or flee'
all gear for emergency (middle part of the spinal cord)
function-speeds up heart rate, stimulates breathing, inhibit digestive system, inhibits urinary system, dilates pupil of the eye, produces liquid with mucus saliva in the salivary gland, raise blood pressure but will stop sending signals to stop as well, sweat is stimulated, adrenal gland is stimulated (adreniline) dilates air way (pulls air in)

Receptors

Sensory
specialized neurons (each sense has a special receptor)- changes a stimulus into a nerve impulse called TRANSDUCTION

senses generates a

receptor potential

eye receptors

photoreceptors

eye external anatomy

protection is blinking reflex,corneal reflex, eyelid
conjunctiva- mucous membrane (very thin on cornea) transparent (allows light through
lacrimal glands-produces tears
lysozymes- drains in duct in lacrimal bone (keep eye lubricated prevents infections by each enzyme)

three layers of wall of the eye

sclera
choroid
retina

sclera

dense fibrous connective tissue, blood vessels and nerves (gives it shape)
CORNEA- becomes clear

choroid

contains melanin and blood vessels
CILIARY BODY(muscle- attached to LENS by suspensory ligaments also makes aqueduct humor
controls lens of eye
consists of the IRIS and PUPIL

Retina

rods and cones (receptors for vision
BLIND SPOT- where the optic nerve enters (no receptor there)
FOVEA CENTRALIS- allows for the clearest vision (has most of the cones) there are more rods than cones. Rods are the night vision for black and white. Cones are for the day vision for red green and blue.

color blindness

messed up cones

vitamin A

good for the cones in the eye

Anterior and Posterior chamber

contains aqueduct humor (clear fluid in front of the eyes has slow circulation and is made by the ciliary body and drains out the CANAL of SCHLEMM

Lens

suspensory ligaments. Helps focus the light on the retina. Its flexible and has the an automatic reflex. ligament relax the lens becomes more convex has close vision and opposite for far vision

Vitreous humor

for the shape, gel (its like jello but clear) does not circulate.

4 factors for normal vision

1)refraction-bending the light rays, focuses,reduces and inverts. Cornea is main refractor, lens fine tunes
2)accommodation-ability to focus at different distances. LENS and SYMPATHETIC-for far visions and PARASYMPATHETIC for near vision
3)constriction and dilation of pupil (Iris part ANS)
4)Convergence-both ees same view and eye muscles

taste receptors

chemoreceptors

Taste sense

adaption (can raise threshold)
taste buds are the receptors
receptors distinguish sweet, salty, sour, bitter, and umami (meaty)

smell receptor

chemoreceptors

smell sense

adaption (can raise threshold)
olfactory epithelium is the receptor
at the top of the nasal cavity

Touch receptor

mechanoreceptor

Touch sense

adaption (can raise threshold)
meissners corpuscle are the receptors
found really close to the epidermis

pressure receptor

mechanoreceptor

pressure sense

pacinian corpuscles are the receptors
found deep in the dermis

Pain receptors

nociceptors

pain sense

free nerve endings are the receptors
can respond to more than one stimulus
stimuli: chemical, mechanical, thermal, plymodal
bradykinin-chemical in body that stimulates pain receptors
stimulus will still control
receptors are found in the skin but inside the body as well

temperature receptors

thermoreceptors

temperature sense

adaption (can raise threshold)
found in the skin by fee nerve ending that distinguishes cold and hot

position receptors

proprioreceptors

position sense

receptors for muscles are the muscle spindles. muscle length, body movements (to cerebellum)
receptors for tendons and ligaments are the Golgi tendon organs and they cause tension

spinal reflex

begins at the receptor. The impulse travels through the dendrites to the dorsal root to the cell body into the sensory neuron in the spinal cord. It synaspes in the gray matter with a dendrite and cell body then synaspes with an axon of the motor neuron. The impulse goes out the ventral root to the muscle.

where are the tracts located in the spinal cord

the white matter

name the 3 layers of the meninges in order from the brain to the bone

pia mater-arachnoid- dura mater

a collection of axons and dendrites wrapped with connective tissue

a nerve

spinal cord starts and ends and is called a what

starts at the medulla ends at L2 and cauda equina

where is the choroid plexus located

in the ventricles

how does CSF get from lateral ventricles to the third ventricle?

inter ventricular foramen

what are the functions of CSF

protection, transport and waste

the cranial nerves that are only motor

3,4,6,11,12

the cranial nerves that are only sensory

1,2,8

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