A&P II Chapter 17: The Special Senses

The general senses include _________ and the receptors are located in the entire body

temperature, pain, touch, pressure, vibration, proprioception

The special senses include ____

smell, taste, hearing, equilibrium, vision

The receptors for the special senses are located on __________

a specific sensory organ

What is sensation?

conscious or subconscious awareness of change in external or internal environment

An example of subconscious sensation is ______

blood pressure

Sensation requires _______

1. Stimulus

2. Sensory receptor

3. Neural pathway

4. Brain region for integration

What is perception?

Conscious awareness

What is adaptation?

decreased receptor response with prolonged stimulation

Adaptation has a ______ perception and it’s speed ______ with receptor

decreased, varies

Olfaction _____ adapts, while pain doesn’t adapt much at all

rapidly

Free nerve endings

• Nociceptors

• thermoreceptors

• bare dendrites associated with pain, thermal, tickle, itch, and touch receptors

Encapsulated nerve endings

• Mechanoreceptors

• dendrites enclosed in a connective tissue capsule for pressure, vibration,

Mechanoreceptors

detect mechanical pressure, provide sensations of touch, pressure, vibration, proprioception, and hearing and equilibrium

• monitor stretching of blood vessels and internal organs

Specialized cells are ________

osmoreceptors, baroreceptors, chemoreceptors, proprioreceptors, photoreceptors

Osmoreceptors

Sense the osmotic pressure of body fluids

Baroreceptors

Sensory receptors for pressure

Chemoreceptors

Detect chemicals in mouth (taste), nose (smell), and body fluids

• Dendrites (hair cells), i.e. Olfactory hairs, gustatory hairs

Proprioreceptors

Hair cells of inner ear for equilibrium

Photoreceptors

In the retina that convert light into electrical signals and enable vision

Fast, “take your breath away” pain associated with superficial injury or trauma and travel over A pain fibers (acute/fast)

Somatic Pain

Somatic pain has ___________ neurons, which increases conduction velocity and makes the action potential go quicker

myelinated

Dull or aching pain that develops more slowly over time and travels over C pain fibers (chronic/slow)

Visceral pain

C pain fibers are usually ________

unmyelinated

With visceral pain, sensory neurons from ______ converge on same pathways as sensory neurons from the ______. This can lead to the phenomenon of referred pain

organs, skin

Referred pain happens because of

the convergence of the cutaneous pain pathways

In somatic sense organs, the receptors are located in ________

the entire body

In special sense organs, the receptors are located on ________

a specific sensory organ localized to the cranial region

Somatic sense organs have (uneven or even) distribution?

uneven

Special sense organs have (uneven or even) distribution?

even

Somatic sense organs have nerve integration through the spinal nerves, while special sense organs have nerve integration through the _______ nerves.

cranial

The cranial nerve for olfaction is the _________ nerve

olfactory

The cranial nerve for gustation (anterior 2/3 tongue) is the ___________ nerve

facial

The cranial nerve for gustation (posterior 1/3 tongue) is the _________ nerve

glossopharyngeal

The cranial nerve for gustation (pharynx, epiglottis) is the _________ nerve

vagus

The cranial nerve for hearing, equilibrium is the _________ nerve

vestibulocochlear

The cranial nerve for vision is the ________ nerve

optic

The cranial nerves for motor are the _________ nerve, ____________ nerve, and the _________ nerve

oculomotor, trochlear, abducens

Sense receptors and sensory neurons are stimulated and send _______ ______ (beginning of the neural path) to the central nervous system

action potential

Supporting cells are for _________

insulation and secretions

Basal cells are stem cells, which means they are _______________ cells for normal growth, development, and repair/healing

regenerative

The least regenerative is _______

hearing

Smell is a _______ sense

chemical

The human nose contains 10 million - 100 million receptors for smell in the __________ ________ of the superior part of the nasal

olfactory epithelium

The olfactory epithelium covers the inferior surface of the ___________ _____ (of the ethmoid bone of the skull) and extends along the superior nasal concha

cribriform plate

Chemoreceptors detect ______ given off by organisms and substances around us

molecules

Olfactory receptors include _________ (columnar epithelium), _______ (replace the olfactory sensory neurons regularly), and _________ (olfactory receptor neurons)

epithelial support cells, basal cells, and olfactory sensory neurons

The epithelial support cells, basal cells, and olfactory sensory neurons are on the olfactory epithelium, which is bad placement because much of the air inhaled flows down the nasal passages without contacting the ______________

olfactory epithelium

________ __________ (Bowman’s glands) produce mucus that is used to dissolve odor molecules so that transduction may occur to easily bind receptors (chemical → electrical)

Olfactory glands

Transduction is a type of _____ conversion

energy

Olfactory Receptors - Detection of Molecules

1. Gas molecules/chemicals dissolve in the mucus covering the olfactory epithelium

2. Those chemicals bind to “odorant receptors” located in the membrane of the olfactory sensory neuron

3. Receptor potentials are generated

Gentle random movement of cilia on the sensory neurons help “mix the covering mucus” and this _______ the efficiency of the chemical to dissolve

increases

Olfactory receptors are _______ sensitive, _____ adapt (due to fatigue of the odorant receptor and the inhibition of the action potentials) there are almost 1000 different type of odorant receptors

highly, rapidly

Step one of Olfactory Pathway