General and Special Sensory Organs

Sensory organs

Organs that monitor internal and external environment

Interceptors

This sensory organ classification responds to sensation from organs

Photoreceptors

Because certain cells which in the eye are sensitive to visible light, these are within the eye

Sent to both sides of the brain

The binocular vision results in information from both eyes meaning

Transducers

these translate mechanical stimuli into electrical signals

Cristae

These are the sensory receptors in the semicircular canals. Each is actually an expanded neuromast organ(hair cells and cupula)

Sensory receptors

Codes/translate environmental stimuli into nerve impulses and send to CNS; messages can be conscious/ unconscious

Perceptions from sensory receptors

Sensations that are consciously recognized such as our view of the world

View of the world

Partially determined by how sensory receptors detect and nervous system processes data

Dogs and bats

What vertebrate possess the ability to perceive specific stimuli through high frequency sounds

Eagles and hawks

What vertebrates possess the ability to perceive specific stimuli through visual acuity

Rattlesnakes

What vertebrates possess the ability to perceive specific stimuli through infrared light

Humans

What vertebrates possess the ability to perceive specific stimuli through color vision

Black and white

How do MOST mammals perceive the world

Perception of the world

Because MOST mammals see the world in black and white, this is limited (or) enhanced by availability and sensitivity of sensory receptors

Conscious sensations

These are subjective interpretations of our environment such as pain and taste

Pain and taste

What two conscious sensations do not exist in the environment but instead arise from events occurring in the brain

Sensory nerves

All stimuli from sensory receptors are carried by these

Nerves

Conducts electrical impulses

Optic, olfactory, auditory, and taste nerves

These types of sensory nerves carry the SAME kind of electrical impulse

Nervous system can be fooled

Because sensory nerves carry the SAME kind of electrical impulses, an artificial stimulation of auditory nerve can be perceived as sound. This results in

Different sensations

What results from different interpretations by the nervous system

Indirectly

How are many stimuli actually perceived

Environmental stimuli and the way it is interpreted

Chemical and photic energies (taste, color, and pain) result from a CNS interpretation of single or multiple stimuli from one or several sensory organs. Because of this, we need to distinguish between what

Sensory neurons and associated tissues

What two components make up sensory organs

Sensory neuron

Component of the sensory organ and specialized cell for detecting and transmitting information from the external or internal environment to the CNS

Dendrites and axons

What are the two components of the sensory neuron

Dendrites

This component of the sensory neuron carries impulses to the cells

Axons

This component of the sensory neuron carries impulses away from the cell

Acts as a transducer thus translates energy from one form into another

What is the function of sensory neurons in sensory organs

Light, mechanical, and chemical

What types of stimuli are converted into an electrical impulse from the sensory neuron in sensory organs

Accessory tissues

Component of sensory organs and adjacent to the tip of sensory fiber(nerve)

Acts to amplify stimulus

What is the function of accessory tissues in sensory organs

Somatic and visceral sensory organs, exteroceptors, interceptors, proprioceptors, and general and special sensory organs

What are all the sensory organ classifications

Somatic sensory organs

This sensory organ classification is associated with skin, body surface, and skeletal muscles

Visceral sensory organs

This sensory organ classification is associated with viscera

Exteroceptors

This sensory organ classification receives input form environment

Proprioceptors

This sensory organ classification is within striated muscles, joints, and tendons

General sensory organs

This sensory organ classification is widely distributed to obtain data on touch, temperature, and proprioceptors

Special sensory organs

This sensory organ classification is localized and highly specialized

Free receptors, encapsulated receptors, and receptors associated with nerve endings

What are the three types of general sensory organs

Free receptors

This type of general sensory organs has NO specialized associations with other structures

Increase area that is monitored

Because the terminus of the free receptors may branch(arborize) thus function to

Monitor pain, heat, cold, pressure, and touch

What is the function of free receptors

Free receptors

A toothache is stimulated from tissue damage and is an example of what type of general sensory organ

Free receptors

This type of general sensory organ is located in skin, cornea, oral cavity, tooth pulp, and intestines

Encapsulated receptors

This type of has its terminus enclosed within some form of specialized structure

Capsules

This is is located in encapsulated receptors and are connective tissue structures that serve to enhance the deformation of nerve endings

They assist in the initiation of a nerve impulse

What is the result of capsules in encapsulated receptors

Meissner's and Pacinian corpuscle, corpuscle of Rufffini, and end bulb of Krause

What are some examples of encapsulated receptors

Meissner's corpuscle

This example of encapsulated receptors are located in DERMIS and send information on TOUCH to CNS

Pacinian corpuscles

This example of encapsulated receptors are located in SKIN, JOINTS, and DEEP TISSUES/ may be present in PANCREAS and send information on PRESSURE

Corpuscle of Ruffini

This example of encapsulated receptors are located in DERMIS and send information on HEAT

End bulbs of Krause

This example of encapsulated receptors are located in DERMIS and send information on COLD

Receptors associated with nerve endings

This type of general sensory organ has its terminus(of axon) wrapped around another organ. An example of this is the hair follicle as its nerve ending wraps around the follicle

Proprioceptors

This is the only receptors associated with nerve endings in general sensory organs

Proprioceptors

This is a sense that is mostly based on data from associated sensory receptors in muscles, tendons, and joints

Provide information to CNS on limb flexion and muscle contraction

What is the primary purpose of proprioceptors

Before and after movement

When is the CNS informed on limb, body position, and the location of part(Brachium) from proprioceptors

Autonomic adjustments

Because proprioceptors are processed subconsciously, what are these also known as

muscle spindles and golgi tendon organs

What are the two receptor types associated with proprioceptors

Skeletal muscles

Where are the muscle spindles located

extrafusal muscle fibers

When discussing muscle spindles, 'normal' skeletal muscle cells(those producing to move a body part) are often referred to as what

To maintain muscle tone(tonus) even when relaxed

What is the function of muscle spindles

Alpha motor neurons

These are a type of nerves that innervate the extrafusal muscle fibers in muscle spindles

Muscle spindles

Receptors type associated with proprioceptors and are a complex of specialized muscle fibers and nerve components that lie among the extrafusal muscle fibers

intrafusal muscle fibers

These are modified striated muscle fibers in muscle spindles

Gamma motor neurons

These are a type of nerves that innervate the intrafusal muscel fibers of the muscle spindle

Nuclear bag and nuclear chain intrafusal muscle fibers

What are the two types of intrafusal muscle fibers in the muscle spindle

nuclear bag intrafusal muscle fibers

This type of intrafusal muscle fibers are innervated by an annulospiral nerve(or a primary afferent sensory nerve)

Nuclear chain intrafusal muscle fibers

This type of intrafusal muscle fibers are innervated by a flower spray nerve(or a secondary afferent sensory nerve)

Tonus and stretch reflex

What are the two mechanisms of action in the muscle spindle

Tonus

This mechanism of action in muscle spindles begin when there is too much relaxation in the muscle cause the spindle to sag

Stretch reflex

This mechanism of action in muscle spindles begin with muscle fibers stretching causing the muscle spindles to stretch

Stretch reflex

This mechanism of action in muscle spindles is important in postural muscles and its action is modulated through the cerebellum

Golgi tendons organs

This receptor type associated with proprioceptors is located in the tendons and lie along the line of muscle action

Tendon recorders/ send info on muscle force to CNS

What is the function of golgi tendon organs

Chemical, electromagnetic, mechanical, and electrical

What are the specific type of stimuli that the special sensory organs are restricted to

Chemoreceptors, radiation receptors, and mechanoreceptors

What are the special sensory organ receptors

Chemoreceptors

These chemical stimuli causes an electrical impulse(mechanism remains uncertain)

taste and smell

What are two type of chemoreceptors

Pheromones

These are chemicals that serve as messages and are released to influence behavior or physiology of another individual

Exocrine glands

What produces pheromones

Nasal passages

This special sensory organ is responsible for olfaction(sense of smell)

Chemoreceptors

These are specialized cells and associated structures located in nasal passages that act translate chemical reactions into smell

Olfactory epithelium, sensory cells, and bulb

What are the three structural components of the nasal passages

Olfactory epithelium

This structural component of the nasal passage area specialized patch of epithelium in the superior area of the nasal cavity

Olfactory sensory cells

This structural component of the nasal passages are modified nerve cells that act as chemoreceptors

Apical end

This end of the olfactory sensory cells in the nasal passage is tuft of cilia

Basal end

This end of the olfactory sensory cells in the nasal passage becomes an axon that extends up through the cribiform plate and into the olfactory bulb

Olfactory nerve

This is inside the olfactory sensory cells of the nasal passages and are made up of all these SHORT axons joined together

Olfactory bulb

This structural component of the nasal passage send LONG axons(together called the olfactory tract) to the brain

Mitral cells

Inside the olfactory bulb of the nasal passages are these synapses with the axons extending from olfactory epithelium

Limbic system(emotion) and corpus striatum(group of important nuclei)

These receive DIRECT olfactory input from the olfactory bulb in the nasal passages

Taste buds

These are the mouths chemoreceptors of taste

One week

What is the lifespan of taste buds on the tongue

Papillae

Taste buds reside in these walls of projections called

Filliform, fungiform, and circumvallate

What are the types of papillae in taste buds

Filliform

This type of papillae in the taste buds are pointed and threadlike. NO taste buds are present here

Fungiform

This type of papillae in the taste buds are mushroomed shaped and has some taste buds