Lab Exam 1 Review

What are general senses?

Senses that respond to touch, pressure, pain, heat, cold, stretch, vibration, and changes in body position.

What are the five special senses?

Vision, hearing, equilibrium (balance), smell, and taste.

What are exteroceptors?

Receptors that respond to external stimuli; found near the body surface (skin).

What are interoceptors (visceroreceptors)?

Receptors that respond to stimuli from internal organs, such as stretch and chemical changes.

What are proprioceptors?

Receptors in muscles, tendons, joints, and ligaments that monitor body position and movement.

What are nonencapsulated receptors?

Sensory receptors without a connective tissue capsule.

What do free nerve endings detect?

Pain and temperature.

What do Merkel (tactile) discs detect?

Light touch.

What do hair follicle receptors detect?

Light touch and bending of hair.

What are encapsulated receptors?

Sensory receptors surrounded by a connective tissue capsule.

What do Meissner corpuscles detect?

Light pressure and discriminative touch.

What do bulbous corpuscles detect?

Deep pressure and stretch.

What do Pacinian (lamellar) corpuscles detect?

Deep pressure, vibration, and stretch.

What do muscle spindles detect?

Muscle stretch (proprioception).

What is a sensory transducer?

A receptor that converts a stimulus into a nerve impulse.

What is sensation?

Awareness of a stimulus.

What is perception?

Interpretation of the meaning of a stimulus.

What are the four cutaneous sensations?

Touch, heat, cold, and pain.

Which sensory receptors are the most numerous?

Pain receptors.

What is punctate distribution?

Sensory receptors are clustered in specific locations rather than evenly distributed.

Where are touch receptors most densely clustered?

Hands and face.

What is two-point discrimination?

The ability to distinguish two closely spaced points touching the skin as separate points.

What is the two-point threshold?

The smallest distance at which two points of contact are felt as two separate points.

What does the two-point discrimination test measure?

Tactile sensitivity and receptor density.

How is the two-point threshold determined?

Gradually change the distance until the subject correctly identifies two separate points.

What does a small two-point threshold indicate?

High tactile sensitivity and a high density of sensory receptors.

What does a large two-point threshold indicate?

Lower tactile sensitivity and fewer sensory receptors.

Which body areas have the smallest two-point threshold?

Fingertips, lips, and face.

What is tactile location?

The ability to determine which area of the skin has been touched.

What is sensory adaptation?

A decrease in receptor response when a constant stimulus remains over time.

How is touch receptor adaptation demonstrated?

Place coins on the forearm with eyes closed and note how long the sensation persists.

How is temperature receptor adaptation demonstrated?

Expose the skin to different temperatures and observe how sensation decreases over time.

What is referred pain?

Pain felt in one location but originating from another area of the body.

Examples of referred pain

Heart → left arm/jaw

Pancreas → back

Liver/Gallbladder → shoulder/neck

Sinus → tooth

Throat infection → ear.

What is a stimulus?

A change in the internal or external environment detected by sensory receptors.

what is the blue line?

afferent

What is the redline?

efferent

What is the green line?

interneuron

What is a reflex?

A rapid, predictable, involuntary motor response to a stimulus.

What are the two types of reflexes?

Inborn (intrinsic) reflexes and learned reflexes.

Are reflexes voluntary or involuntary?

Involuntary.

What are autonomic (visceral) reflexes?

Reflexes that are usually not consciously perceived and involve internal organs.

What structures are involved in autonomic reflexes?

Smooth muscle, cardiac muscle, and glands.

What are examples of autonomic reflexes?

Digestion, blood pressure regulation, salivation, sweating, and pupillary reflexes.

What type of reflex is the pupillary reflex?

Autonomic (visceral) reflex.

What are somatic reflexes?

Reflexes involving stimulation of skeletal muscles.

What type of muscle is involved in somatic reflexes?

Skeletal muscle.

What are the two major divisions of the nervous system?

Central nervous system (CNS) and peripheral nervous system (PNS).

What structures make up the central nervous system (CNS)?

Brain and spinal cord.

What are the two divisions of the peripheral nervous system (PNS)?

Somatic nervous system and autonomic nervous system.

What does the somatic nervous system control?

Skeletal muscles.

What does the autonomic nervous system control?

Smooth muscles, cardiac muscles, and glands.

What are the two divisions of the autonomic nervous system?

Sympathetic nervous system and parasympathetic nervous system.

What is the receptor in a reflex arc?

The site where the stimulus acts.

What does the sensory neuron do in a reflex arc?

It transmits afferent impulses to the CNS.

What does afferent mean?

Information traveling toward the CNS.

What is the integration center?

One or more synapses within the CNS where information is processed.

What does the motor neuron do in a reflex arc?

It conducts efferent impulses from the integration center to an effector organ.

What does efferent mean?

Information traveling away from the CNS.

What is the effector in a reflex arc?

A muscle fiber or gland that responds to efferent impulses.

How does a muscle respond as an effector?

By contracting.

How does a gland respond as an effector?

By secreting.

What are the components of a reflex arc in order?

Receptor → sensory neuron (afferent) → integration center (CNS) → motor neuron (efferent) → effector.

What is the patellar reflex?

A deep tendon reflex caused by stretching the quadriceps muscle, resulting in knee extension.

How is the patellar reflex tested?

Tap the patellar tendon below the patella with a reflex hammer.

What is the expected response of the patellar reflex?

The quadriceps contracts, causing the knee to extend (leg kicks forward).

What muscle is responsible for the patellar reflex response?

The quadriceps muscle.

If the patellar tendon is tapped and the knee does not extend, what response is abnormal?

An absent or reduced patellar reflex.

What is the calcaneal tendon (Achilles) reflex?

A deep tendon reflex that tests ankle plantar flexion through stimulation of the Achilles tendon.

How is the calcaneal tendon (Achilles) reflex tested?

Tap the calcaneal (Achilles) tendon at the back of the ankle.

What is the normal response of the calcaneal tendon (Achilles) reflex?

Plantar flexion of the foot (foot points downward).

What muscles contract during the calcaneal tendon (Achilles) reflex?

Gastrocnemius and soleus muscles.

What is dorsiflexion?

Movement of the foot upward toward the shin.

What is plantar flexion?

Movement of the foot downward away from the shin.

The patient pulls their toes toward their nose. What movement is this?

Dorsiflexion.

The patient points their toes downward like pressing a gas pedal. What movement is this?

Plantar flexion.

What are superficial reflexes?

Reflexes produced by stimulation of the skin surface.

How are superficial reflexes different from deep tendon reflexes?

Superficial reflexes involve skin stimulation; deep tendon reflexes involve muscle stretch.

Give examples of superficial reflexes.

Plantar reflex, corneal reflex, and abdominal reflex.

What is the Babinski test?

A neurological test where the sole of the foot is stroked to assess the plantar reflex.

How is the Babinski test performed?

Stroke the lateral side of the sole of the foot from the heel toward the toes.

What is the normal adult response during the Babinski test?

Toes curl downward (plantar flexion).

What is a positive Babinski sign?

The big toe extends upward and the other toes fan outward.

Is a positive Babinski sign normal in adults?

No. It may indicate a neurological problem.

Is a positive Babinski sign normal in infants?

Yes. It is normal because their nervous system is still developing.

What is a somatic reflex?

A reflex that involves skeletal muscle as the effector.

What type of muscles are involved in somatic reflexes?

Skeletal muscles.

Are patellar and calcaneal tendon reflexes somatic reflexes?

Yes. They cause skeletal muscle contraction.

What is the difference between a somatic reflex and an autonomic reflex?

Somatic reflex → skeletal muscle response

Autonomic reflex → smooth muscle, cardiac muscle, or gland response.