A&P 2 Lab 1-2

Irritability

Potential of a nerve to respond to some kind of stimulus (chemcial, electrical, mechanical)

Conductivity

Movement of a nerve impulse along the length of the neuron

Reflex Arcs

What reflexes occur through

Reflex Arc Structure

Receptor

Afferent (sensory) Neuron

Integration Center (brain or spinal cord) OR Interneuronal

Effert (motor) Neuron (the neuron taking the response from CNS)

Effector (stucture causing an effect)

Somatic Reflex

Effector in the Skeltal Muscle

Visceral or Autonomic Reflex

An effector is a gland, smooth muscle, or cardiac muscle

Polysynaptic Reflex Arcs

Most reflexes involve many neurons with many synapses

Monosynaptic Reflex Arcs

Reflexes involve with just two neurons, a sensory neuron and a motor neuron with one synapse between them

What do reflexes depend on?

Stimulus or an environmental cue

A receptor that is sensitive to a stimulus, a sensory neuron, a motor neuron, and an effector

What has a receptor that is sensitive to stimulus, a sensory neuron, a motor neuron, and an effector

Integration center and polysynaptic reflex arc

Integration Center Location

Between the sensory and motor neurons

Integration Center's Job

Take information to the brain by ascending tracts to the spinal cord

What happens if reflex tested are too little or overeggarted

Indication of disease in the nervous system

Hyporeflexic

showing less than average response

Hyperreflexic

showing an exaggerated response

What do stretch reflexes determine

Used to determine one's neurological condition or identity conditions such as hypothyroidism. CNS damage = reflexes exaggerated

Hypothyroidism

The reflexes are depressed

Stretch Reflexes

Receptors are in the muscle spindles, stretching muscle cases and increasing action potentials in the sensory neuron and subsequently synapsing with the motor neuron. This illustrates the muscle causing contraction in the muscles that is stretched.

Example of Stretch Reflexes

Paterllar reflex: striking the patellar ligament stretches the quadriceps muscle --> sensory neurons transmit information to the spinal cord --> motor neurons stimulate quadriceps muscle to contract --> extend leg

The triceps branchii reflex tests what nerve

Radial nerve

The biceps branchii reflex tests what nerve

Musculocutaneous nerve

Plantar Response

Extension of the hallux in response to the stroke of the plantar surface of the foot is

Extensor Plantar Response OR Babinski Reflex

Normal for babies of the age 1, but not for adults

Why is the Babinski reflex normal of age of 1

Incomplete myelination of some nerve fibers

What is it called for the result of flexion of the toes in adults

Flexor Plantar Response

Why would the flexor plantar response occur in adults

Due to damage to the phymindal tracts, important in determining spinal damage

General Senses

Touch, pain, and pressure can be felt in many parts of the body

Specific Senses

Sight, smell, and taste are perceived only by specific, localized receptors

True or False: All sense receptors are uniformly distributed throughout the body

False

Punctate Distribution

Uneven distribution of sense receptors, where some areas are clustered with receptors and others are not

Modality

is the type of sensory information being detected, such as touch, pain, temperature, or pressure.

Receptors

Receiving units of the body that respond to stimuli. They transform neural signals, transmitted by sensory nerves and neural tracts, to the somatosensory cortex that interprets the message.

IF ANY LINK IS BROKEN IN SENSORY CHAIN, PERCEPTION OF STIMULUS CANNOT OCCUR

Photoreceptors

Detect light

Thermoreceptors

Located in the skin, detecting change in temperature

Proprioceptor

Detect changes in tension such as those in joints

Nociceptors

Transmit the sensation of pain present as naked nerve endings in areas such as the skin or stomach

Mechanoreceptors

Perceive mechanical stimuli (touch receptors, receptors that determine hearing or equilibrium in the car)

Baroreceptors

Respond to changes in pressure such as blood pressure

Chemoreceptors

Respond to changes in the hemcial envioirment (taste and smell)

Meissner Corpuscles Location

Upper portion of dermis (1 out of the 2 allow for perception of very light touch stimuli)

Merekel Discs location

Located in the upper dermis and lower epidermis (2 out of the 2 allow for perception of very light touch stimuli)

Pacinian (lamellated) Corpuscles

Sense pressure, such as if you lean against a wall or feel a vibration

Tonic Receptors

Pain receptors constantly perceive painful stimuli rather than adapting to it

Phasic Receptors

Touch receptors will adapt to the stimulation created when clothing contacts the body's surface, meaning touch receptors are an example of _____ receptors.