Transcript Nervous/ENDO lecture

• Central Nervous
System (CNS) –
– Brain and spinal cord
• Peripheral Nervous
System (PNS) –
– Made up of nerves that
attach to CNS
Peripheral Nervous System
P e rip h e ra l N e rvo u s S yste m
S ke le ta l
A u to n o m ic
(S o m a tic )
S y m p a th e tic
P a ra sym p a th e tic
Functional Subdivisions of the
PNS
• PNS contains 2
functional
subdivisions
– Sensory
(afferent) nerves
conduct sensory
impulses to CNS
from receptors in
organs and tissues
– Motor (efferent)
nerves conduct
impulses away
from CNS to
muscle effectors
and glands
• Somatic Nervous
System (SNS) –
– Controls voluntary and
involuntary skeletal
muscle contractions
– Involuntary skeletal
contraction – reflex
– Single neuron system
• Autonomic Nervous
System (ANS) –
– Controls activity of
smooth and cardiac
muscles
– 2 neuron system
• 1st: from CNS to ganglion
• 2nd: from ganglion to
effector
Subdivisions of Motor
Division (PNS)
Subdivisions
of ANS
• Sympathetic
division –
– Fight or flight
• Parasympathetic
division –
– Regulates resting
functions
• Ex., digesting food
• “ Fight or flight”
response
• Release
adrenaline and
noradrenaline
• Increases heart
rate and blood
pressure
• Increases blood
flow to skeletal
muscles
• Inhibits digestive
functions
Sympathetic
CENTRAL NERVOUS SYSTEM
Brain
Dilates pupil
Stimulates
Inhibits salivation
Relaxes bronchi
Spinal
cord
Salivary
glands
Lungs
Accelerates heartbeat
Inhibits activity
Heart
Stomach
Pancreas
Stimulates glucose
Secretion of adrenaline,
nonadrenaline
Relaxes bladder
Sympathetic
ganglia
Stimulates ejaculation
in male
Liver
Adrenal
gland
Kidney
Parasympathetic
• “ Rest and CENTRAL NERVOUS SYSTEM
digest ”
system
• Calms body to
conserve and
maintain
energy
• Lowers
heartbeat,
breathing
rate, blood
pressure
Brain
Contracts pupil
Stimulates salivation
Spinal
cord
Constricts bronchi
Slows heartbeat
Stimulates activity
Stimulates gallbladder
Contracts bladder
Stimulates erection
of sex organs
Gallbladder
Summary of ANS differences
Autonomic nervous system controls physiological arousal
Sympathetic
division (arousing)
Pupils dilate
Decreases
Parasympathetic
division (calming)
EYES
Pupils contract
SALIVATION
Increases
Perspires
SKIN
Dries
Increases
RESPIRATION
Decreases
Accelerates
HEART
Slows
Inhibits
DIGESTION
Activates
Secrete stress
hormones
ADRENAL
GLANDS
Decrease secretion
of stress hormones
• Made up primarily of 2
types of cells:
– Neurons
– Supporting cells
• CNS - neuroglia
(glial cells)
– Astrocytes,
microglia, ependymal
cells,
oligodendrocytes
• PNS – satellite cells,
Schwann cells
• Made up of a cell bodies,
dendrites, and axons
• Cell body (or soma)
– Contains large nucleus and
Nissl bodies (Rough E.R.),
primary site of protein
synthesis
– Most located within CNS
where they are protected by
hard bones of skull and
vertebral column
– Collection in CNS is called
“nuclei” whereas in PNS
they are called “ganglia”
Neurons
More on
Neuron
Structure
• Dendrites
– Short, highly branched
signal receptive regions
of nerve cell
– Convey incoming
message toward the
cell bodies
• Each nerve cell
(neuron) has only one
axon
– Impulse generating and
conducting region of
neuron
Myelin Sheath of the Axon
• Whitish, fatty protein
layer
• Serves to protect and
electrically insulate axon
• Increases the speed of
transmission of nerve
impulses (up to 150
times faster)
• Only associated with
axons, not dendrites
REVIEW:
Functional Classification
• Neurons are grouped according to the
direction in which the nerve impulse travels
relative to the CNS
• Based on this there are sensory, motor,
and association neurons
– Sensory – transmit impulses from skin or other
organs toward CNS
– Motor – carry impulses away from CNS to effector
organs
– Association (interneurons) – lie between motor
and sensory neurons
Neuron Video
neurilemma
Neuroglia (CNS)
• CNS has 4 different types of supporting cells (neuroglia)
– Abundant and diverse
– Limited knowledge of each function due to difficulty in
isolating individual cells
• Ependymal cells
– Line central cavities of brain and spinal cord
– Beating of cilia help to circulate the cerebrospinal
fluid (CSF)
– CSF: protection of brain and transport of vital
nutrients and waste
• Astrocytes
– Attach neurons to capillaries, linking them to
nutrient supply
Neuroglia CONT….
• Oligodendrocytes
–Branches wrap around neuron fibers,
forming an insulating covering called a
myelin sheath
• Microglia
–Monitor health of nerve cells
–If foreign invader detected or cell damaged,
many microglia head to the area, transform
into macrophages, and protect the CNS by
phagocytizing the microorganisms or
neuronal debris
Neuroglia
(CNS)
Label your Synapses
Diagram
Use pages 392 and 406 in the AP book
• HINTS FOR YOU:
= Sodium ions
= Potassium ions
= Calcium ions
= synaptic vesicles w/
neurotransmitters
= chemical gated channels
Action potential
• http://highered.mcgrawhill.com/sites/0072495855/stude
nt_view0/chapter14/animation__t
he_nerve_impulse.html
ANIMATION OF
CHEMICAL SYNAPSES
• http://highered.mcgrawhill.com/sites/0072495855/stude
nt_view0/chapter14/animation__
chemical_synapse__quiz_1_.html
Animation of ENTIRE SYNAPTIC
PROCESS with ACTION POTENTIAL
Sodium/Potassium Pump
• http://highered.mcgrawhill.com/sites/0072495855/stude
nt_view0/chapter2/animation__h
ow_the_sodium_potassium_pump
_works.html
Action Potential Graph
• Know what happens at
each part of the graph
with relationship to the
pre-synaptic and postsynaptic activities.
• Look at the HANDOUT
with the graph!!
• Also known as “Nerve Impulses”
• Self-regenerating wave of electrochemical
activity that allows neurons to carry a signal over
a distance (“game of telephone”)
• Pulse-like waves of voltage that
travel along several types of cell
membranes
•
http://outreach.mcb.harvard.edu/animations/
actionpotential.swf
• Initiation/Resting Stage:
– Some K+ channels are open: K+ diffusion occurring
– Initiated by stimulus above a certain intensity or
threshold (~-70mV – resting potential)
– Could be a pin prick, light, heat, sound or an
electrical disturbance in another part of the
neuron (“telephone call”)
– Electrical signal rises
from changes in
permeability of the
neuron’s axon membranes
to specific ions (Na+ & K+)
Depolarization (Rising Phase)
• K+ Channel gates are closed
• Stimulus causes gate in the Na+ Channel to open
• High concentration of Na+ outside, Na+ diffuses into
neuron
• Electrical potential changes to ~ +40 mV.
Repolarization (Falling Phase)
• Depolarization causes K+ Channel gate to immediately
open & Na+ Channel close
• K+ diffuses out of neuron
• Reestablishment of initial electrical potential of ~-60
mV.
Refractory Period (Recovery Phase)
• Na+ & K+ Channels cannot be opened by a stimulus
• Na+/K+ Pump actively (ATP) pumps Na+ out of & K+ into
neuron
• Reestablishment of ion distribution of resting neuron
• This AP acts as stimulus to neighboring proteins &
initiates AP in another part of neuron
• Wave of APs travel from
dendrites to axon terminals
• At axon terminal, electrical
impulse is converted to a
chemical signal (neurotransmitter)
Per. 2 start, Fri
Per. 4, WU go over handout
http://bcs.whfreeman.com/thelifewire/content/chp44/4402002.html
• Getting the message across
(the synapse)?
–
http://www.mind.ilstu.edu/curriculum/neurons_intro/neurons_intro.php
– At axon terminal, chemical
signal (NT) crosses synapse
between adjacent neurons
• Starts AP on this neuron
– This activates Ca2+ channel to open
• Ca2+ diffuses into neuron
• Causes NT vesicles to move to end & fuse with cell membrane
• Through exocytosis, NTs are released into synapse
– NTs diffuse across synapse & bind to NT receptors on
another neuron
• Causes Na+ channels to open & AP is initiated in next neuron
• Information from one
neuron flows to another
neuron across a synapse…
– a small gap separating
neurons that consists of:
– a presynaptic ending that
contains neurotransmitters,
mitochondria & other
organelles,
– a postsynaptic ending that
contains receptor sites for
neurotransmitters &
– a synaptic cleft or space
between the presynaptic &
postsynaptic endings.
Let’s Review…
How do neurons communicate?
• What is another name for the nerve impulse that travels
from the axon hillock through the axon to the axon terminal?
• What are the 4 main phases of an Action Potential?
• What happens in the Rising Phase?
• Falling Phase?
• Recovery Phase?
• Resting Potential?
• What ion entering the neuron
instigates the movement of synaptic
vesicles to the cell membrane?
• What do the vesicles release into
the synapse?
• What happens after the NTs are
released into the synapse?
Central Nervous System
Brain
•Brain and
Spinal
Cord
Spinal
Cord
• Average adult male’s brain weighs
approximately 1.6 kg (~3.5 lbs)
• Average female’s: 1.42kg
• According to body weight, though…they
are relatively equal in size
Brain has 2 Hemispheres
• Left & Right sides are
separate
• Corpus Callosum :
major pathway
between hemispheres
• Some functions are
‘lateralized’
– Language, numbers on
left
– Color and music on right
• Lateralization is never
100%
Corpus Callosum
Right
Hemisphere
Left
Hemisphere
Corpus Callosum
• Major ( but not only)
pathway between sides
• Connects comparable Medial surface of right hemisphere
structures on each side
• Permits data received
on one side to be
processed in both
hemispheres
• Aids motor
coordination of left and
right side
Corpus Callosum
Contralateral Motor
Control
• Movements
controlled by motor
area
• Right hemisphere
controls left side of
body
• Left hemisphere
controls right side
• Motor nerves cross
sides in spinal cord
Motor Cortex
Somatosensory Cortex
Each hemisphere is
divided into 4 lobes
Frontal
Parietal
Occipital
Temporal
Cerebellum
• Cover and
protect CNS
• Protect blood
vessels and
enclose
venous sinuses
• Contain
cerebrospinal
fluid
• Form divisions
within the
skull
Cerebral White Matter
• Deep to the gray
matter of cortex
• Aids
communication
between cerebral
areas and
between cerebral
cortex and lower
CNS
• Spinal cord has just the
opposite type of matter
http://www.brainexplorer.org/brain-images/white_matter.jpg
Frontal Lobe
• Contains
primary
motor cortex
• No direct sensory
input
• Important
planning and
sequencing areas
Broca’s area for
speech
• Prefrontal area for
working memory
Frontal
Lobe
Working
Broca’s
Memory
Area
Motor
Cortex
Occipital Lobe
• Input from Optic
nerve
• Contains primary
visual cortex
Occipital
Lobe
– most is on surface
inside central fissure
• Outputs to
parietal and
temporal lobes
Visual
Lobe
Temporal Lobe
• Inputs are auditory,  Contains primary
auditory cortex
visual patterns
– speech
Auditory
recognition
Cortex
– face recognition
– word recognition
– memory
formation
Temporal
Lobe
• Outputs to limbic
System, basal
Ganglia, and
brainstem
Parietal Lobe
• Inputs from
multiple senses
 borders visual &
auditory cortex
 Outputs to Frontal
lobe
 hand-eye
coordination
 eye movements
 attention
Somatosensory
Parietal
Cortex
Lobe
• Cerebral
Hemispheres –
– Has outer cortex of
gray matter (neural
bodies)
• Diencephalon –
– Thalamus,
hypothalamus, and
epithalamus
• Brain Stem –
– Midbrain, pons,
medulla
• Cerebellum –
– Has outer cortex of
gray matter
Regions &
Organization
Label the
worksheet on the
brain!!
• I will place the
worksheet under
the document
camera for you
to view!!
Cerebral Hemispheres
• Approx. 83% of
total brain mass
• Covered with
elevations called
gyri and shallow
grooves called
sulci
• Deeper grooves,
called fissures,
separate major
regions of the
brain
Cerebral Cortex
• It is the gray matter of the cerebrum
• Enables us to perceive, communicate, remember,
understand, appreciate, and initiate voluntary
movement
– It enables conscious behavior
• Contains 3 functional areas:
– Motor – control voluntary motor functions
– Sensory – provide conscious awareness of
sensation
– Association – integrate diverse information
for purposeful action
The Brain
Stem
• Includes:
– Midbrain
– Pons
– Medulla oblongata
• Structurally different
from brain because it
has deep gray matter surrounded by
white matter (similar to spinal cord)
• Coordinates head and eye movement when we visually
follow a moving object or see something out of corner of eye
• Coordinates head reflex movement to unexpected auditory
stimulus
The Diencephalon
• Surrounded by
the cerebral
hemispheres
• Consists of 3
bilaterally
symmetric
structures:
http://www.web-books.com/eLibrary/Medicine/
Physiology/Nervous/diencephalon.jpg
– Thalamus
– Hypothalamus
– Epithalamus
The Thalamus
• Egg-shaped
• Makes up 80% of
diencephalon
• Within the thalamus
a sorting-out and
information
“editing” process
occurs
The Hypothalamus
•
•
•
•
Caps the top of the brain stem
Main visceral control center of the body
Vitally important to the homeostasis of the body
A few of its functions:
– Regulates involuntary nervous system activities (blood
pressure, motility of digestive tract)
– Perceives pleasure, fear, rage and sex drive (emotions)
– Regulates body temp. by initiating
– Regulates feelings of hunger and fullness
– Regulates water balance and thirst
– Regulates sleep cycle in response to daylight-darkness cues
received by our eyes
– Controls endocrine system functioning – hormonal balance
Epithalamus
• Most dorsal portion of
the diencephalon
• Forms roof of 3rd
ventricle
• Aids with sleep-wake
cycle regulation (pineal
gland)
• Helps with CSF
production
Pons
• Helps to
maintain
normal
rhythm of
breathing
Medulla
Oblongata
• “medulla”
• Most inferior part
of the brain stem
• Adjusts the force
and rate of heart
beat and depth of
breathing
• Regulates
vomiting,
hiccupping,
swallowing,
coughing and
sneezing
The Cerebellum
• Coordinate skeletal
muscle contractions
needed for the
smooth, coordinated
movements of our
daily lives
– Ex., driving,
typing, walking
• Cerebellar activity
occurs
subconsciously
Cerebrospinal Fluid
• Functions:
– Forms cushion for brain and other CNS organs
– Gives buoyancy to brain (which reduces weight by 97%)
to prevent brain from crushing under own weight
– Also helps blood in providing brain with nourishment
• Fun Fact:
– Average adult brain contains 150 ml and is replaced every
3-4 hours
• Application:
– If CSF becomes obstructed, can cause condition called
hydrocephalus
• Enlargement of the head in babies and brain damage in adults
Looks Can Be Deceiving
vWhat are these kinds of pictures called?
vWhat do these do to neuron communication within our Nervous System?
The Dancing Girl
• Look at the
Dancer…
– Which way is she
turning?
• Clockwise?
• Counter-clockwise?
– Now stare at her
bottom foot & squint
your eyes…
• Does she start turning
the other direction?
Get lost
in the
circles
• What happens when
you focus on the
center of a circle?
Anatomy WARM-UP
• Read the article about Phineas Gage
then answer the following questions:
• What was Phineas’ occupation?
• Why is the Phineas Gage
story so popular among
medical science?
• Was there a change
in Gage after the accident?
• Where can you go and view
Gage’s skull?
3rd qtr; week 5; day 2
• On a separate paper, write your
thoughts about this picture…
• Your reactions
• What do you think caused this
situation?
– Based on what you know,
• what kind of repercussions would
this accident have on the nervous
system?
– Now read the following story of
Phineas Gages’ tragic accident…
– Write about your reactions to the
accident
• What surprised you about any info
learned?
• What kinds of things does the prefrontal cortex (lobe) regulate?
Vision
• Photoreceptors
are the visual
receptor cells
• Adult eye
averages 1 inch
in diameter
• Accessory
structures of the
eye protect the
eye or aid in its
functioning
Accessory Structures
•
•
•
•
Eyebrows
Eyelids
Conjunctiva
Lacrimal
apparatus
• Extrinsic Eye
muscles
Lacrimal Apparatus
PAGE 555 in AP
book
• Consists of the
lacrimal gland and
lacrimal ducts
• Lacrimal gland
releases fluid that
contains mucus,
antibodies, and
lysozyme (a bacteriadestroying enzyme)
• Lacrimal gland is
located superior and
lateral to the eye
– It releases fluid, which
is spread over eye by
blinking, and drains via
the medial lacrimal
canals
Eyebrows and Eyelids
• Eyebrows overlie the
supraorbial margins of
the skull
• They shade the eyes
from sunlight and
prevent perspiration
from entering the eyes
• Eyelids cover the eye
when the orbicularis
oculi contract
–Eyelashes (palpabrae)
are richly innervated, • This occurs (blinking)
every three to seven
so anything that
seconds to prevent
touches them,
including a puff of air, desiccation of the eyes
triggers reflex
blinking
Structure of the Eyeball
• Made up of three layers called tunics: fibrous (1),
vascular (2) and sensory (3)
• Fibrous tunic is the outermost coat of the eye
• It is divided into two major regions: the cornea
and the sclera
• The sclera (tough connective tissue) is the
“white of the eye” and functions to protect and
shape the eyeball
• Also serves as sturdy
anchoring point for
extrinsic eye musculature
• PLEASE LABEL
your wksht with
color coding of
your 3 tunics
3
• Though it seems to
appear in many colors
(Iris means rainbow), it
actually only contains
brown pigment
• When an iris contains a
lot of pigment, the eyes
appear brown or black
• If the amount of pigment
is small, the short
wavelengths of light are
scattered from the
unpigmented parts of the
iris, and eyes appear
blue, green, or gray
• Why, then, do newborn
babies often appear to
have gray or blue eyes?
Iris
(Vascular
Tunic)
The Sensory Tunic
Lens
• Contains the lens (hard
disc) which allows an
image that is upside
down and backwards.
• This is the deepest layer
and also has pigmented
cells that absorb light
• Also stores Vitamin A,
which is needed by the
Photoreceptor cells
• The retina contains
millions of
photoreceptors known as
cones and rods
CHECK
YOUR
LABELS!!!
Conjunctiva
• A transparent mucous
membrane that lines the
eyelids and reflects over
the surface of the eyeball
• It functions to lubricate
the eye and to prevent
invasion to the posterior
portion of the eye
• Conjunctivitis is an
inflammation of the
conjunctiva; Pinkeye is a
type of conjunctivitis
caused by bacteria or
virus
More on the Eye
• Cornea is lined with pain
fibers (which is why
contacts can be so tough
to adjust to)
• When cornea is touched,
reflex blinking and increased
lacrimal fluid secretion occur
• Since cornea has no blood supply it is the
only tissue that can be transplanted with
very little fear of rejection (does not have
contact with immune system)
Internal
Chambers
• Filled with aqueous humor
which is produced in the
posterior chamber and
drains from the anterior
chamber
• If this drainage is blocked,
pressure within the eye
may increase and cause
compression of the retina
and optic nerve-a
condition called glaucoma
• Exam to diagnose is
simple…a puff of air at the
sclera will produce a
measurable amount of
deformation
Colorblind Tests
• http://www.toledobend.com/colorblind/Ishihar
a.html
• http://colorvisiontesting.com
/online%20test.htm#demons
tration%20card
ENDOCRINE SYSTEM
• Responsible for sending
messages to target
organs by secreting
hormones
• Moves slower than the
Nervous system
•
ENDOCRINE SYSTEM
• Please label
all of the
glands on your
wksht and
explain what
hormone is
secreted from
each of them.
• Use pages 591692 in the
Anatomy book!
Yes, you will need to
identify what the
hormone does for the
body…MAKE IT
BRIEF!!
THE END
The Ear
• Divided into
three major
regions:
• Inner ear
• Middle ear
• Outer ear
LABEL YOUR WORKSHEET
Page 573 in AP book
•
• Auricle = the ear
• made up of the helix
(rigid portion) and
lobule (no cartilage)
• directs sound waves
into auditory canal
• canal is short (2.5
cm) and curved and
extends to the
tympanic membrane
• Canal is lined with
hairs, sebaceous
glands, and
aprocrine sweat
glands called
ceruminous glands
Outer Ear
Middle Ear
• Small, air-filled
cavity within the
petrous portion of
temporal bone
• Eustachian tube
links middle ear to
superiormost part
of the throat
– Normally this is
closed, but yawning
and swallowing
opens this tube
briefly to equalize
pressure
• Contains the three smallest bones
in the body: the ossicles
• Malleus (hammer) – secured to
the tympanic membrane
• Incus (anvil)- connects other
bones
• Stapes (stirrup) – connects to the
inner ear (via the oval window)
• Tensor tympani muscle attaches
the auditory tube. The stapedius
muscle runs from the wall of the
middle ear cavity and inserts into
the stapes
• These two muscles work together
to prevent damage to the inner ear
under extremely loud conditions
Inner Ear
• Located deep
within the
temporal bone
and posterior
to the eye
socket
• Made up of the
vestibule,
cochlea, and
semicircular
canals
Vestibule
• Central egg-shaped
cavity that medially
borders the middle
ear
• Has oval window in
its lateral wall
• Contains perilymph
(similar to CSF)
• Houses equilibrium
Sensors called
maculae that
respond to the pull of
gravity and report
changes of head
position
Semicircular Canals
• Made up of an
anterior,
posterior, and
lateral canal
• Also have
receptors to
help with
equilibrium
Cochlea
• About half the size
of a pea
• Contains three
hollow cavities:
Scala
vestibuli(terminates
at oval window),
cochlear duct, scala
tympani (terminates
at round window)
• Cochlear duct
contains spiral
organ of Corti, which
is the receptor organ
for hearing
Hearing
• Sounds set up vibrations in air that
beat against the ear drum
• This pushes the ossicles that press
fluid in the inner ear against
membranes
• This pressure on the membranes
pulls on tiny hair cells that stimulate
nearby neurons that give rise to
impulses that travels to the brain,
where they are interpreted
Hair Cells in the
Spiral Organ of
Corti
• Lining the organ of
Corti you find
roughly 16,000
hearing receptor
cells called
cochlear hair cells
sandwiched
between basilar
membrane and
tectorial membrane
Deafness
• Two types: conduction or sensorineural
• Conduction deafness – occurs when
something interferes with conduction of
sound vibrations to the fluids of the innner
ear
• Sensorineural deafness – results from
damage to neural structures at any point in
the hearing pathway
– This typically result from the gradual loss of the
hearing receptor cells:
• Throughout life
• Single explosively loud noise
• Prolonged exposure to high-intensity sounds, which
cause these cells to stiffen (IPODs)