Exercises 21, 22, 26 - Reflexes, General Senses, Special Senses: Olfaction & Gustation

reflex

is a rapid and predictable automatic responses to stimuli

• Can be innate (intrinsic)

• Can also be learned (acquired)

Mediated over neural pathways is called ?

reflex arcs

include all of those reflexes that involve stimulation of the skeletal muscles by the SNS

Somatic reflexes

• Activates smooth muscle, cardiac muscles, and glands

are mediated by the ANS and we usually aren’t aware of them

autonomic reflexes

• Regulate body functions such as digestion, elimination, blood pressure, salivation, and sweating

it is the site of the stimulus

Receptor

transmits the stimulus

Sensory neuron

in spinal cord

integration center

conducts to impulses to the effector

motor. neuron

muscle or gland

effector

identify this structure

dorsal root ganglion

identify this structure

unipolar neuron/ sensory or afferent neuron

identify this structure

multipolar neuron/ motor or efferent neuron

identify this structure

integration center multipolar neuron/ interneuron

identify this structure

effector (could be muscle, gland etc)

identify this structure

receptors

what do the somatic reflexes affect

they affect skeletal muscle

a somatic, spinal reflex that occurs in response to stretching within a muscle

stretch reflex

what happens when you strike the patellar or achilles tendon

it causes the muscle spindles within the associated muscle to stretch and increase their nerve activity

• Causes the muscle fibers to contract and resist the stretching

how to preform a bicep reflex and what’s its normal response

Tap the biceps brachii tendon near its insertion at the radial tuberosity

• normal response is flexion at the elbow

what reflex is this

bicep reflex

what reflex in this

triceps reflex

what reflex is this

ankle-jerk reflex

how to preform a tricep reflex and what’s its normal response

Tap the triceps brachii tendon near its insertion at the olecranon of the ulna

• Normal response is extension at the elbow

how to preform a ankle-jerk reflex and what’s its normal response

Tap the calcaneal tendon

• normal response is plantar flexion

come back to slide 13

Superficial cord reflexes

Result from pain & temperature changes in skin and mucosal

what reflex is this

plantar reflex

• normal response toes curl down in adults

what reflex is this

babinski reflex

• normal response toes curl up but abnormal in adults

corneal reflex

Cranial nerve V (trigeminal)

• Initiating this reflex causes the subject to blink

• Function is to protect the eye

gag reflex

Cranial nerves IX (glossopharyngeal) and X (vagus)

• The posterior pharyngeal wall elevates as the pharyngeal muscles contract, and the subject gags

what does the autonomic reflex affect

affects smooth muscles, cardiac muscle, and glands etc

Pupillary light reflex

• Ipsilateral constriction of the pupil

  • Reflex occurs on the same side stimulated

consensual reflex

• Contralateral constriction of the pupil

  • Reflex occurs on the opposite side stimulated

what are sensory receptors

• The dendritic endings of sensory neurons

  • May be free or encapsulated

• Specialized cells that associate with the dendrites of sensory neurons

Exteroceptors

Senses stimuli external to the body, Found close to the body surface

• touch, pain, and vision

Interoceptors or visceroceptors

Senses stimuli arising from within the body

• visceral pain, nausea, stretch pressure

Proprioceptors

Senses the position & movements of the body

• Located in inner ear, muscles, tendons & joints

  • Muscle spindles & golgi tendon organs

Thermoreceptors

cold and warm receptors

Mechanoreceptors

Physical deformation: vibration, touch, pressure, stretch, tension, hearing, balance

• Located in skin, viscera, joints, inner ear

Chemoreceptors

Respond to chemicals: odor, taste, dissolved chemicals in body fluids

Nociceptors

Respond to tissue damage: trauma or ischemia

identify this structure

free nerve ending

• Bare dendrites of a sensory neuron and most abundant in epithelia & connective tissue

  • Associated with pain, thermal, tickle, itch and some touch

identify this structure

hair follicle receptor

• Also called a root hair plexus

• Free nerve ending entwines in the hair follicle

• what cell Sense hair movements

identify this structure

tactile corpuscle (meissner’s corpuscle)

• Heavy touch, pressure, stretching of the skin, joint movements

  • Located in the dermis, subcutaneous, ligaments, tendons and joint capsules

identify this structure

tactile discs (merkel disc)

• Sense light touch: texture, shapes, edges

• Merkel discs=merkel cell + free nerve ending

• Located in the stratum basale of the epidermis

identify this structure

Bulbous corpuscle (Ruffini corpuscle)

• Heavy touch, pressure, stretching of the skin, joint movements

  • Located in the dermis, subcutaneous, ligaments, tendons and joint capsules

identify this structure

lamellar corpuscle (pacinian corpuscle)

• Deep pressure, stretch, tickle, vibration

  • Deep in the dermis and mainly found in the hands, genital, feet, breast, & some organs

Separate Receptor Cells

Receptor cell synapses with a sensory neuron

• Found in the skin, inner ear and taste buds

GENERAL SENSORY RECEPTORS OF THE SKIN are also called..

cutaneous receptors

what cell structure is this

Tactile (Meissner) corpuscle

• Heavy touch, pressure, stretching of the skin, joint movements

  • Located in the dermis, subcutaneous, ligaments, tendons and joint capsules

what cell structure is this

Lamellated (Pacinian) corpuscles

• Deep pressure, stretch, tickle, vibration

  • Deep in the dermis and mainly found in the hands, genital, feet, breast, & some organs

what cell structure is this

Bulbous (Ruffini) corpuscles

• Heavy touch, pressure, stretching of the skin, joint movements

  • Located in the dermis, subcutaneous, ligaments, tendons and joint capsules

Identify this structure

Dermal papilla

Identify this structure

Epidermal ridges

what cell structure is this

Tactile disc (Merkel disc )

• Sense light touch: texture, shapes, edges

• Merkel discs=merkel cell + free nerve ending

  • Located in the stratum basale of the epidermis

what is gustation

is a taste and is a chemical sense

• chemicals dissolved in salvia

what is olfaction

it is smell and is a chemical sense

• chemicals are dissolved in fluids of the nasal membranes

Olfactory epithelium

• contains the olfactory receptors which are localized on the roof of the nasal cavity and are covered by mucus

  • They are bipolar neurons with cilia

Supporting cells

epithelial surround the olfactory receptors

basal cells

stem cells

olfactory glands

responsible for mucus production

what structure is this

olfactory bulb

what structure is this

olfactory nerve

what structure is this

olfactory epithelium

what structure is this

cribriform plate of ethmoid bone

what structure is this

olfactory tract

what does the tongue contain

lingual papillae

what structure is this and what’s its function

Foliate

• on the sides of the tongue containing the taste

what structure is this and what’s its function

fungiform papillae

• mushroom like containing the taste buds

what structure is this and what’s its function

circumvallate

• In a V formation on the back of the tongue. Contain taste buds.

what structure is this and what’s its function

filiform

• numerous but do not contain any taste

gustatory cells or taste cells

Several nerve fibers enter each taste bud and supply sensory nerve endings to each gustatory cell

• When chemicals contact the gustatory hairs of a gustatory cell, the gustatory cell depolarizes

what is a gustatory receptor cell

receptor cell for taste

what is a transitional cell

developing gustatory cells

What is gustatory hair

the sensitive part of the taste cells

what cell structure is this and what’s it function

taste pores

• opening for the gustatory hair

what cell structure is this

circumvallate papilla

what cell structure is this

foliate papilla

What cell structure is this

Taste buds

what cell structure is this

filiform papillae

what cell structure is this

taste pores

Facial

anterior 2/3 of the tongue

glossopharyngeal

posterior 1/3 of the tongue

trigeminal

will carry all the other information such as texture and temperature

sweet receptors

respond to Na+ (metallic) ions

sour receptors

respond to acidic solutions

bitter receptors

respond to alkaloids

umami (delicious) receptors

respond to the amino acid glutamate found in cheese and meat

Gustatory discrimination

is from the combined effects of

• smell, texture and temperature on taste