anatomy lecture 3 exam
less light in
pupillary constriction
more light in
pupillary dilation
Our bodies are constantly exposed to sensory
information called?
stimuli
Our conscious awareness to these stimuli is called
sensation
Stimuli are detected by ___ in our body
receptors
receptors - temperature, pain, touch, stretch, and pressure
general senses
receptors – gustation (taste), olfaction, vision, equilibrium, and audition (hearing)
special senses
structures that detect stimuli and monitor changes in either the external or internal body
receptors
General sense receptors are distributed
throughout the?
skin and organs
Special sense receptors are housed in complex?
organs in the head
3 criteria used to describe receptors
1. stimulus origin
2. receptor distribution
3. modality of stimulus
3 types of stimulus origin receptors
1. exteroceptors
2. interoceptors
3. proprioceptors
found in skin or mucous membranes such as nasal and oral cavities, vagina, and anal canal
exteroceptors
found in the walls of viscera; detecting stretching, oxygen depravation, temperature, and pressure
interoceptors
found in muscles, tendons and joints; detecting body and limb movement, muscles contraction/stretching
proprioceptors
3 types of receptors based on distribution
1. somatic receptors
2. visceral receptors
3. special senses
found within the body wall; they include receptors for chemicals, temperature, pain, touch, proprioception, and pressure
somatic receptors
found within the walls of the viscera; they respond to chemicals, temperature, and pressure
visceral receptors
located only in the head; gustation, olfaction, vision, equilibrium, and hearing
special senses
6 major classes of receptors based on the stimulating agent
1. chemoreceptors
2. thermoreceptors
3. photoreceptors
4. mechanoreceptors
5. baroreceptors
6. nociceptors
detect specific dissolved molecules
chemoreceptors
detect changes in temperature
thermoreceptors
detect changes in light
photoreceptors
detect physical deformation due to touch, pressure, vibration, and stretch
mechanoreceptors
detect pressure changes within body structures
baroreceptors
detect tissue damage and pain
nociceptors
mechanoreceptors that react to touch, pressure, temp, and vibration stimuli
• Most numerous type of receptor
• Located in the dermis and subcutaneous layer of the skin
tactile receptors
taste receptors housed in specialized organs termed taste buds
gustatory cells
sense of taste
gustation
stem cells
basal cells
Each gustatory cell has a dendritic ending called ____ or taste hair.
gustatory microvillus
taste hair extends through
taste pore
sense of smell
olfaction
Inside the nasal cavity are paired ______
consisting of several components
olfactory organs
olfactory epithelium - consists of three distinct cell types:
1. olfactory receptor cells
2. supporting cells
3. basal cells
At the apical end of the olfactory receptors cells are
nerve endings called ____ that project through the mucous covering the olfactory epithelium
olfactory hairs
capable of detecting light, color, and movement
photoreceptors
Three principal layers form the wall of the eye
fibrous tunic
vascular tunic
retina
composed of cornea and sclera
fibrous tunic
Anterior part, transparent, avascular
cornea
makes up the majority of the fibrous tunic; considered the “white” of the eye and allows for the attachment of the extrinsic eye muscles to the eye
sclera
contains a vast network of capillaries, which supply nutrients and oxygen to the retina
choroid
composed of choroid, ciliary body, and iris
vascular tunic
Composed of ciliary muscles and ciliary processes; ciliary muscles contract or relax shaping of the lens to focus incoming light onto the retina
ciliary body
Pigmented part of the eye. Black hole is called
the pupil, which allows light to pass on to the retina
iris
Internal layer of the eye wall composed of two layers
retina
attached to the choroid; absorbs light energy that passes through the retina and provides photoreceptors with vitamin A
pigmented layer
houses photoreceptors and other associated neurons
neural layer
• Area of retina that contains the highest proportion of cones and almost no rods
• Sharpest area of vision
fovea centralis
"Blind spot” on retina
• Located where ganglion cell axons exit retina to form optic nerve (CN II)
• Lacksphotoreceptors
optic disc
between the lens and the cornea--Aqueous humour
anterior cavity
posterior to the lens and anterior to the retina--Vitreous humour
posterior cavity
3 layers of the neural layer
photoreceptor layer
bipolar cells
ganglion cells
outermost layer composed of rods (dim) and cones (color)
photoreceptor layer
synapse with photoreceptors and ganglion cells
bipolar cells
innermost layer of the retina; axons of these cells leave the retina and form the optic nerve
ganglion cells
The ear is divided into three distinct anatomic regions:
1. external ear
2. middle ear
3. inner ear
Skin covered, funnel-shaped,elastic cartilage supported structure called the
auricle
Auricle leads to a bony tube called the external
acoustic meatus, which ends at the
tympanic membrane
3 auditory ossicles:
1. malleus
2. incus
3. stapes
attached to tympanic membrane; articulates with incus
malleus
middle of the three bones; articulates with stapes
incus
fits into the oval window on cochlea
stapes
Located in spaces within the petrous portion of the temporal bone
inner ear and bony labyrinth
spaces in petrous portion of the temporal bone are called
bony labyrinth
fluid filled tubes
1. vestibular complex
2. cochlea
detects balance and rotation
vestibular complex
hearing organ
cochlea
• Utricle and Saccule
• Macula
vestibule
Ampulla
Crista ampullaris
semicircular canals
Contains hair cells that are sensory receptors for balance/equilibrium
maculae structure
On their apical surface of each hair cell are many stiff microvilli called
stereocilia
one long cilium called
kinocilium
gelatinous mass is known as the
otolithic membrane
Within each semicircular canal is an expanded region called the
ampulla
The ampulla contains an elevated region called the
crista ampullaris
The stereo cilia/kinocilia of the hair cells embed into an overlying gelatinous dome called the
cupula
organ for hearing
cochlea
cochlea contains 3 chambers:
1. cochlear duct - medial
2. scala vestibuli - superior
3. scala tympani - inferior
spiral organ consists of thick sensory epithelium that includes hair cells and supporting cells on the
basilar membrane
Thespiralorganislocatedwithinthecochlearductand
detects movement of endolymph
spiral organ
The stereocilia of hair cells project into an overlying mass
called the
tectorial membrane
The spinal cord and its attached spinal nerves serve two important functions:
1. A pathway for sensory and motor impulses
2. Responsible for reflexes, which are the quickest reactions to a stimulus
The spinal cord is partitioned into an ____
matter region and an ____ matter region:
inner gray, outer white
dendrites and cell bodies of neurons, unmyelinated axons, and glial cells
gray matter
myelinated axons
white matter
Centrally located in spinal cord
• Sectioned shape resembles butterfly
gray matter
subdivided into:
1. anterior horns
2. lateral horns
3. posterior horns
4. gray commissure
are ductless organs secrete their molecular products (hormones) into the bloodstream
endocrine glands
All endocrine organs have an extensive distribution of many
many
blood vessels
Endocrine glands produce informational molecules
called
hormones
Hormones can only affect cells (target cells) or organs (target organs) that have ____ for a specific hormone.
receptors
the study of the structural components of the endocrine system, the hormones they produce, and the effects of these hormones on target organs
endocrinology
3 major classes of hormones based on their chemical structure:
1. peptide hormones
2. steroid hormones
3. biogenic amines
growth hormone
peptide hormones
estrogen/testosterone
steroid hormones
thyroid hormone
biogenic amines
Hormone secretion is regulated by a self-
adjusting mechanism called a
feedback loop
2 types of feedback loop
1. negative
2. postive
in a negative feedback loop, a ___ starts the process
stimulus