A&P II practical

Irritability

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

Conductivity

The movement of a nerve impulse along the length of the neuron

Thershold voltage

minimum voltage required for nerve conduction

Procaine Hydrochloride

Novocain

Receptor

The structure that receives the stimulus

Afferent (sensory) neuron

The neuron taking the stimulus to the CNS

Integration center

The brain or spinal cord or interneuron

Efferent (motor) neuron

The neuron taking the response from the CNS

Effector

The structure causing an effect

somatic reflex

If the effector is skeletal muscle, the reflex is called a _________.

Visceral; autonomic reflex

If the effector is a gland, smooth muscle, or cardiac muscle, the reflex is called a _________ or __________.

Polysynaptic reflex arc

reflexes involved with many neurons and many synapses

Monosynaptic reflex arc

A reflex that involves just two neurons, a sensory neuron and a motor neuron with one synapse between them

stimulus

Reflexes depend on a _______.

Hyperreflexive

Showing an exaggerated response

Hyporeflexive

Showing less than average response

Normal movement

Movement of an inch or two

Patellar reflex

Example of a stretch reflex

Patellar reflex

Tests the conduction of the femoral nerve

This is a monosynaptic reflex ark

Musculocutaneous nerve

What nerve does the Biceps Brachii reflex test?

radial nerve

What nerve does the triceps Brachii reflex test?

Tibial Nerve

What nerve does the calcaneal tendon reflex test?

Extensor Plantar Response (Babinski Reflex)

The extension of the hallux (big toe) in response to stroking the plantar surface of the foot

Flexor plantar response

Flexion of the toes

Maximum recruitment voltage in nerve conduction

Maximum muscle contraction; all neurons of nerves are stimulated

reflex

Involuntary, predictable responses to stimuli

General senses

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

Specific senses

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

Punctuate distribution

Sense receptors are not uniformly distributed throughout the body, but are absent or are few in number in some parts of the body while densely clustered in others

Receptors

The receiving units of the body that respond to stimuli

Photoreceptors

Detect light

Thermoreceptors

Located in the skin; detect changes in temperature

Proprioreceptors

Detect changes in tension, such as those in joints

Nociceptors

transmit the sensation of pain and are present as naked, nerve endings in areas such as the skin or stomach

Mechanoreceptors

Perceive mechanical stimuli (for example, touch receptors or receptors that determine hearing or equilibrium in the ear)

Baroreceptors

Respond to changes in pressure such as blood pressure

Chemoreceptors

Respond to changes in the chemical environment (for example taste and smell)

Modality

No perception without environmental stimulus or input

light, heat, sound, pressure, and specific chemicals

Pain receptors

sense pain and respond to many environmental stimuli

Meissner Corpuscles and Merkel Discs

Allow for the perception of very light touch stimuli

Pacinian Corpuscles

Sense pressure (like when you lean against a wall or feel a vibration)

Warm and cold receptors

When you are at a comfortable temperature, both of these receptors are firing. If you increase or decrease the skin temperature beyond the perception of these receptors, pain receptors are stimulated.

Tonic receptors

Constantly perceive stimuli

Phasic receptors

Adapt to a stimulus

Referred pain

The perception of pain in one area of the body when the pain is actually somewhere else

An example is the pain felt in the left shoulder and arm when a person is suffering from a heart attack or chest pain

more warm pain receptors

Are there more cold receptors or warm receptors in the skin?

Due to the fact that there are not as many nerve endings on the forearm, it is harder to locate the precise location

In terms of receptor density, describe why it is difficult to find the same location on the forearm when your eyes are closed

proprioceptors

What kind of receptor determines the weight of an object when you pick it up?

Pupil

Opening located in the center of the eye and is surrounded by the colored iris

Sclera

The white of the eye and is covered by a membrane known as the conjunctiva

Protective portion of the eye that is an attachment point for the muscles of the eye and helps maintain the intraocular pressure (pressure inside the eye)

Conjunctiva

The first layer covering the sclera

Composed of epithelial tissue

an important indicator of a number of clinical conditions

Lateral commissure and medial commissure

Where the eyelids join together

Lacrimal Caruncle

Small piece of tissue near the medial commissure

Intraocular pressure

Maintains the shape of the eye and keeps the retina attached to the posterior wall of the eye

Fibrous tunic

the sclera and the cornea form this

Attached to the sclera

Extrinsic muscles

Lacrimal Apparatus

a structure important in the maintenance of the exterior of the eye

Consists of lacrimal gland (located superior and lateral to the eye)

Nasolacrimal duct

lacrimal secretions (tears) bathe and protect the eye and clean dust from its surface and the fluid drains through the ______________ into the nasal cavity.

Cornea

The structure of the eye important for bending light rays that strike the eye, allowing us to focus light

Composed of dense connective tissue and is avascular

Anterior chamber

Directly behind the cornea is the ____________, between the cornea and the iris

Posterior chamber

Between the iris and the lens

Anterior and posterior chambers

Filled with aqueous humor, which is produced by the ciliary body

scleral venous sinus (canal of Schlemm)

Aqueous humor is produced each day and this amount is absorbed by the __________________.

Sphincter Pupillae (circular muscles)

of the iris and constricts in bright light which reduces the diameter of the pupil

Pupil

The space enclosed by the iris

Dilator Pupillae (radial muscles)

Constrict in dim light, increasing the diameter of the pupil

Lens

Behind the pupil

Made of a crystal-line protein

Suspensory ligaments

The ciliary muscles in the ciliary body contract and the __________ that attach to the lens loosen, decreasing the pull on the lens which makes the lens more round for focusing on closer images

Vitreous chamber

Behind the lens

Occupies most of the posterior portion or fundus of the eye

Filled with vitreous humor

Vitreous humor

A clear jelly like fluid that maintains the shape of the eyeball

Fibrous tunic

The outermost layer of the eye composed of dense connective tissue

Vascular tunic

Consists of the choroid, the ciliary body, and the iris

The blood vessels found in this layer nourish the eye, and the pigmentation prevents light from scattering and blurring vision

Nervous tunic

The layer closest to the vitreous humor

Consists of the retina

Retina

Prevents light scattering in the eye which can blur vision

Has a inner neural layer that converts light to action potentials

Ganglionic, bipolar, and photoreceptive layers

The retina is composed of three layers

Photoreceptive layer

Composed of rods and cones

Rods

Important for determining the shape of objects and for seeing in dim light

Cones

Involved in color vision and visual acuity (determining fine detail) oh

Macula

At the posterior region of the eye

In the center of this is the fovea centralis

Fovea Centralis

A region where the concentration of cones is greatest

In this area, the cone cells are not covered by the nervous tunic as the cells are in the other parts of the retina

When you focus on an object intently you are directing the image to this

Near point

The minimum distance an object can comfortably be held in focus

Binocular or stereoscopic vision

Allows certain animals to perceive depth, which is vital when judging how far away the next branch is

astigmatism

The cornea or lens is not perfectly smooth

Hyperopia (farsightedness)

If a positive number provides a clear view of the eye

The eyeball is short, and the image is focused posterior to the retina

Myopia (nearsightedness)

If the image is clear with negative number

The eyeball is long and lenses with negative diopters focus the images farther back on the retina

tapetum lucidum

Improves night vision and some animals

Produces the “eye shine” of nocturnal animals

Afterimage

If someone looks at a bright light or object against a dark background, then closes their eyes, they can still see a light object in a dark background.

Negative afterimage

Person sees a dark object against a light background

Rhodospin

the photosensitive pigment of the eye

Composed of retinal and the protein opsin

When light strikes the retina, the purple colored rhodospin splits into its two component parts and becomes pale, a process known as bleaching

Optic disc

Region where the retinal nerve fibers exit from the back of the eye and form the optic nerve

Blind spot

The exit of nerve fibers leaves a small circle at the back of the eye devoid of photoreceptors. This region, the optic disc, is also known as the ____________.

Mechanoreception

Hearing and balance are considered

Wavelength and amplitude

sound is measured in ___________.

Decibels

The amplitude of the weight is measured in units called __________.

Hertz

Frequency is measured in cycles per second or __________.

proprioception

Balance involves receptors in the inner ear, visual cues, and __________.

Static and dynamic balance (kinetic balance)

Two types of balance are sensed by the inner ear:

Static balance

A person can determine their non-moving position, such as standing upright or lying down

Dynamic balance

Motion is detected

Sudden acceleration, abrupt turning, and spinning are examples of this

the tympanic cavity, ear ossicles, and auditory tube

Middle ear contains: