endocrine and nervous system · neuron is stimulated by another neuron or by the sense organs....
TRANSCRIPT
Main Function:
This communication system controls and
coordinates functions throughout the body and responds to internal and
external stimuli.
Our nervous system
allows us to feel pain.
Consists of: brain, spinal cord, nerves and sense organs
Sense Organs: Eyes, Skin, Ears, Nose & Tongue
A nerve is an organ
containing a bundle
of nerve cells called
neurons.
Neurons carry
electrical messages
called impulses
throughout the
body. Picture shows hundreds of
severed neuron axons
cell
body
muscle
tissue
TYPICAL MOTOR
NEURON
Axon dendrite
synapse
cell body
Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called synapse between two neurons.
Neurotransmitters
Synapse (gap)
The message
is transferred
when RECEPTORS receive neurotrans-mitters.
(pink
spheres)
Parts of a Neuron 1. Cell body: contains nucleus & most of the
cytoplasm
2. Dendrites: projections that bring impulses into the neuron to the cell body.
3. Axon: long projection that carries impulses away from cell body
1
3 2
Sensory Neuron
Interneuron
Motor Neuron
Sensory Neuron
Interneuron
Motor Neuron
Muscle Contracts
Synapse
Synapse
Synapse
Sensory
Neuron
carry impulses from
sense organs to
spinal cord & brain
Fun Fact:
Where can the
largest cells in the
world be found?
The giraffe’s sensory and
motor neurons! Some
must bring impulses from
the bottom of their legs
to their spinal cord
several meters away!!
Interneuron
-processes impulses
in brain and spinal
cord
- connect sensory and
motor neurons
Motor Neurons
carry impulses from the
brain & spinal cord to
muscles & glands
Axon End
Axons branching out
to muscle fibers
• Nerves work together with muscles for
movement. An impulse begins when one
neuron is stimulated by another neuron or
by the sense organs.
• The impulse travels down the axons of
Sensory neurons to the brain cells called
Interneurons.
• The brain will then send an impulse
through motor neurons to the necessary
muscle or organs, telling it to contract.
A reflex is an
involuntary
response that is
processed in the
spinal cord not
the brain.
Reflexes protect
the body before
the brain knows
what is going on.
Reflex Arc
brain
Spinal Cord
Cerebellum
Cerebrum
Medulla Oblongata
Consists of: Brain and Spinal Cord
Cerebrum Voluntary or conscious activities of
the body-learning, judgment
Cerebellum Coordinates and balances the
actions of the muscles
Medulla Oblongata
(Brain Stem)
Controls involuntary actions like
blood pressure, heart rate,
breathing, and swallowing
Spinal Cord
The main communications link
between the brain and the rest of
the body
Consists of:
Sensory division
and Motor
division
-includes all
sensory neurons,
motor neurons,
and sense organs
Anatomy and Physiology
• Ophthalmology (Ophth) is study of the eye
• Eyeball
– Organ of sight
– Transmits external image using sensory
impulses via optic nerve to brain
– Brain translates sensory impulses into image
Anatomy and Physiology
• External structures important for vision
– In addition to eyeball
– Eye muscles
– Eyelids
– Conjunctiva
– Lacrimal apparatus
Click here to view an animation on the anatomy of the eye. Back to Directory
Eye Anatomy Animation
The Eyeball
• Composed of three layers:
– Sclera
– Choroid
– Retina
Sclera
• Outermost layer
• Tough protective
layer
• Another term for
sclera is white of
eye
• Anterior portion is
cornea
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.1 – The internal structures of the eye.
Cornea
• Anterior portion of
sclera
• Clear, transparent
• Allows light to
enter
• Bends, or refracts,
light rays
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.1 – The internal structures of the eye.
Choroid
• Middle layer
• Provides blood
supply for eye
• Anterior portion:
– Iris
– Pupil
– Ciliary body
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.1 – The internal structures of the eye.
Iris and Pupil
• Iris
– Colored portion of
eye
– Smooth muscle that
changes size of
pupil
• Pupil
– Opening in center
of iris
– Allows light to
enter into eyeball
Ciliary Body and Lens
• Lens
– Behind iris
– Not actually part of
choroid layer
– Attached to ciliary
body
• Ciliary body
– Pulls on edge of
lens
– Changes shape of
lens so it can focus
light onto retina
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.1 – The internal structures of the eye.
Retina
• Contains sensory
receptor cells that
detect light rays
• Rods
– Active in dim light
– See gray tones
• Cones
– Active only in
bright light
– Color vision
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.1 – The internal structures of the eye.
Retina
• Macula lutea
– Area of retina
where image forms
• Fovea centralis
– Depression in
center of macula
lutea
– High number of
cones
– Point of clearest
vision
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.1 – The internal structures of the eye.
Optic Disk
• Point where the optic nerve leaves eyeball
• Retinal blood vessels enter and leave
through optic disk
• No rods or cones
– Results in blind spot in each eye’s field of
vision
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.2 – Photograph of the retina of the eye. The optic disk appears yellow and the retinal arteries radiate out from it.
Eye Fluids
• Aqueous humor
– Watery fluid
– Located between cornea and lens
• Vitreous humor
– Semi-solid gel
– Located between lens and retina
Muscles of the Eye
• Six muscles that connect eyeball to skull
– 4 rectus muscles pull straight
– 2 oblique muscles pull on an angle
• Contract in combination to change direction
in which each eye is looking
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.3 – The external eye muscles.
Eyelids
• A pair cover each eyeball
• Provide protection from foreign particles,
injury, sun, and trauma
• Both upper and lower edges have eyelashes
or cilia that protect eye from foreign
particles
• Sebaceous glands located in eyelids secrete
a lubricating oil onto surface of eyeball
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.1 – The internal structures of the eye.
Conjunctiva
• A mucous membrane
• Forms continuous covering on underside of
each eyelid and across anterior surface of
each eyeball
• Protects eyeball
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.1 – The internal structures of the eye.
Lacrimal Apparatus
• Lacrimal gland
– Located under outer upper corner of each eyelid
– Produces tears
– Tears wash and lubricate anterior surface of eyeball
• Lacrimal ducts
– Located in inner corner of eye socket
– Collect tears
– Drain into nasolacrimal duct
– Ultimately drain into nasal cavity
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.5 – The structure of the lacrimal apparatus.
How We See
• Light rays pass
through:
– Cornea
– Pupil
– Aqueous humor
– Lens
– Vitreous humor
• Then strike retina
– Stimulating rods
and cones
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.6 – The path of light through the cornea, pupil, lens, and striking the retina.
How We See
• Upside-down
image forms on
retina
• Optic nerve
transmits this image
to brain
• Brain turns upside-
down image into
right-side up image
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.7 – The image formed on the retina is inverted. The brain rights
the image as part of the interpretation process.
Vision
• Vision requires four mechanisms:
– Coordination of external eye muscles so that
both eyes move together
– Correct amount of light admitted by pupil
– Correct focus of light upon retina by lens
– Optic nerve transmitting sensory images to
brain
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.9 – Hyperopia (farsightedness). In the uncorrected top figure, the image would come into focus behind the retina, making the image on
the retina blurry. The bottom image shows how a biconvex lens corrects this condition.
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.10 – Myopia (nearsightedness). In the uncorrected top figure, the image comes into focus in front of the lens, making the image on the retina blurry. The bottom image shows how a biconcave lens corrects
this condition.
Eyeball Pathology
cataract damage to lens causing it to become
cloudy
glaucoma chronic increase in intraocular pressure;
results in atrophy of optic nerve
macular
degeneration
deterioration of macula lutea area of
retina
The Ear at a Glance
• Function of the Ear
– Contains sensory receptors for hearing and
equilibrium (balance)
The Ear at a Glance
• Structures of the Ear
– Auricle
– External ear
– Middle ear
– Inner ear
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Anatomy and Physiology
• Otology (Oto) is study of the ear
• Audiology is study of hearing disorders
• Ear responsible for two senses:
– Hearing
– Equilibrium or sense of balance
• Sensory information carried to brain by
vestibulocochlear nerve
– Cochlear nerve – hearing information
– Vestibular nerve – balance information
Click here to view a video on audiology. Back to Directory
Audiology Video
The Ear
• Ear is subdivided into three regions:
– External ear
– Middle ear
– Inner ear
Click here to view an animation on the anatomy of the ear. Back to Directory
Ear Anatomy Animation
External Ear
• Auricle or pinna
– Only portion visible
– Captures sound
waves
– Directs them
through external
auditory meatus
External Ear
• Auditory canal
– Sound moves along canal
• Cerumen
– Produced by oil glands in auditory canal
– Oily wax slowly flows out of ear canal removing dirt that has stuck to it
External Ear
• Tympanic
membrane
– Commonly called
eardrum
– Sound waves strike
membrane
– Causes it to vibrate
• Tympanic
membrane
separates external
ear from middle ear
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.14 – The internal structures of the outer, middle, and inner ear.
The Middle Ear
• Small cavity
• Located in temporal
bone of skull
• Contains three tiny
bones called
ossicles
– Malleus
– Incus
– Stapes
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.14 – The internal structures of the outer, middle, and inner ear.
Ossicles
• Tympanic
membrane vibrates
incus
• Vibrations amplify
as they move from
one ossicle to next
• Stapes transmits
vibration to oval
window
– Start of inner ear
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.15 – Close-up view of the ossicles within the middle ear.
Eustachian Tube
• Also called auditory tube
• Connects nasopharynx with middle ear
• Opens with each swallow
• Equalizes pressure between middle ear
cavity and atmospheric pressure
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.14 – The internal structures of the outer, middle, and inner ear.
The Inner Ear
• Labyrinth
– Cavity within
temporal bone
– Houses inner ear
• Contains sensory
organs
Sensory Organs of Inner Ear
• Hearing
– Cochlea
– Organs of Corti
• Equilibrium
– Semicircular
canals
– Utricle
– Saccule
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.14 – The internal structures of the outer, middle, and inner ear.
How We Hear
• Sound waves travel down external auditory
canal, strike eardrum
• Eardrum vibrates
How We Hear
• Ossicles conduct vibrations across middle
ear from eardrum to oval window
• Oval window movements initiate vibrations
in fluid that fills cochlea
How We Hear
• Fluid vibrations strike hair cells, bending
small hairs and stimulating nerve endings
• Nerve ending sends electrical impulse to
brain on cochlear portion of
vestibulocochlear nerve
Medical Terminology: A Living Language, Fourth Edition Bonnie F. Fremgen and Suzanne S. Frucht
Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458
All rights reserved.
Figure 13.16 – The path of sound waves through the outer, middle, and inner ear.
Click here to view an animation on inner ear anatomy. Back to Directory
Inner Ear Anatomy Animation
• Main Function:
It releases hormones into the blood to
signal other cells to behave in certain
ways. It is a slow but widespread form
of communication.
Endocrine glands
Release hormones into
the bloodstream.
Hormones are chemicals
released in one part of the
body that travel through
the bloodstream and
affect the activities of cells
in other parts of the body.
Consists of:
Pituitary Gland
Function: It secretes nine hormones that directly regulate many body functions and controls functions of other glands.
Disorders: To much growth hormones (GH) in early childhood can result in a condition called gigantism. To little GH can result in Pituitary Dwarfism.
Robert Wadlow
Thyroid Gland • Function: plays a major role in
regulation the body’s metabolism.
• Disorders: If the Thyroid Gland produces to much Thyroxin, it can cause a condition known as Hyperthyroidism. If to little thyroxin produces it is called Hypothyroidism.
Pancreas • Function: The Insulin
and Glycogen in the Pancreas help to keep the level of glucose in the blood stable.
• Disorders: When the Pancreas fails to produce or properly use Insulin, it can cause a condition known as Diabetes Mellitus.
Adrenal Gland
• Functions:
-The adrenal glands release Adrenaline in the body that helps prepare for and deal with stress.
-Also regulates kidney function.
Ovaries
• Functions:
– Pair of reproductive organs found in women that produce eggs.
– Also secrete estrogen and progesterone, which control ovulation and menstruation.
Testes
• Functions:
– Pair of reproductive glands that
produces sperm.
– Also secrete Testosterone to give
the body its masculine
characteristics.
Interaction of Glands
The hypothalamus is located in the brain and controls the release of hormones from the pituitary gland. It is an important link between the endocrine and nervous systems.
http://www.biocfarm.unibo.it/aunsnc/images/3D%20Obje
cts/Hypothalamus.gif
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